Integration of the functional movement screen into the National Hockey League Combine.

PubMed

Rowan, Chip P; Kuropkat, Christiane; Gumieniak, Robert J; Gledhill, Norman; Jamnik, Veronica K

2015-05-01

The sport of ice hockey requires coordination of complex skills involving musculoskeletal and physiological abilities while simultaneously exposing players to a high risk for injury. The Functional Movement Screen (FMS) was developed to assess fundamental movement patterns that underlie both sport performance and injury risk. The top 111 elite junior hockey players from around the world took part in the 2013 National Hockey League Entry Draft Combine (NHL Combine). The FMS was integrated into the comprehensive medical and physiological fitness evaluations at the request of strength and conditioning coaches with affiliations to NHL teams. The inclusion of the FMS aimed to help develop strategies that could maximize its utility among elite hockey players and to encourage or inform further research in this field. This study evaluated the outcomes of integrating the FMS into the NHL Combine and identified any links to other medical plus physical and physiological fitness assessment outcomes. These potential associations may provide valuable information to identify elements of future training programs that are individualized to athletes' specific needs. The results of the FMS (total score and number of asymmetries identified) were significantly correlated to various body composition measures, aerobic and anaerobic fitness, leg power, timing of recent workouts, and the presence of lingering injury at the time of the NHL Combine. Although statistically significant correlations were observed, the implications of the FMS assessment outcomes remain difficult to quantify until ongoing assessment of FMS patterns, tracking of injuries, and hockey performance are available.

Quantification of Competitive Game Demands of NCAA Division I College Football Players Using Global Positioning Systems.

PubMed

Wellman, Aaron D; Coad, Sam C; Goulet, Grant C; McLellan, Christopher P

2016-01-01

The aim of the present study was to examine the competitive physiological movement demands of National Collegiate Athletic Association (NCAA) Division I college football players using portable global positioning system (GPS) technology during games and to examine positional groups within offensive and defensive teams, to determine if a player's physiological requirements during games are influenced by playing position. Thirty-three NCAA Division I Football Bowl Subdivision football players were monitored using GPS receivers with integrated accelerometers (GPSports) during 12 regular season games throughout the 2014 season. Individual data sets (n = 295) from players were divided into offensive and defensive teams and subsequent position groups. Movement profile characteristics, including total, low-intensity, moderate-intensity, high-intensity, and sprint running distances (m), sprint counts, and acceleration and deceleration efforts, were assessed during games. A one-way ANOVA and post-hoc Bonferroni statistical analysis were used to determine differences in movement profiles between each position group within offensive and defensive teams. For both offensive and defensive teams, significant (p ≤ 0.05) differences exist between positional groups for game physical performance requirements. The results of the present study identified that wide receivers and defensive backs completed significantly (p ≤ 0.05) greater total distance, high-intensity running, sprint distance, and high-intensity acceleration and deceleration efforts than their respective offensive and defensive positional groups. Data from the present study provide novel quantification of position-specific physical demands of college football games and support the use of position-specific training in the preparation of NCAA Division I college football players for competition.

Ball Machine Usage in Tennis: Movement Initiation and Swing Timing While Returning Balls from a Ball Machine and from a Real Server

PubMed Central

Carboch, Jan; Süss, Vladimir; Kocib, Tomas

2014-01-01

Practicing with the use of a ball machine could handicap a player compared to playing against an actual opponent. Recent studies have shown some differences in swing timing and movement coordination, when a player faces a ball projection machine as opposed to a human opponent. We focused on the time of movement initiation and on stroke timing during returning tennis serves (simulated by a ball machine or by a real server). Receivers’ movements were measured on a tennis court. In spite of using a serving ball speed from 90 kph to 135 kph, results showed significant differences in movement initiation and backswing duration between serves received from a ball machine and serves received from a real server. Players had shorter movement initiation when they faced a ball machine. Backswing duration was longer for the group using a ball machine. That demonstrates different movement timing of tennis returns when players face a ball machine. Use of ball machines in tennis practice should be limited as it may disrupt stroke timing. Key points Players have shorter initial move time when they are facing the ball machine. Using the ball machine results in different swing timing and movement coordination. The use of the ball machine should be limited. PMID:24790483

Ball machine usage in tennis: movement initiation and swing timing while returning balls from a ball machine and from a real server.

PubMed

Carboch, Jan; Süss, Vladimir; Kocib, Tomas

2014-05-01

Practicing with the use of a ball machine could handicap a player compared to playing against an actual opponent. Recent studies have shown some differences in swing timing and movement coordination, when a player faces a ball projection machine as opposed to a human opponent. We focused on the time of movement initiation and on stroke timing during returning tennis serves (simulated by a ball machine or by a real server). Receivers' movements were measured on a tennis court. In spite of using a serving ball speed from 90 kph to 135 kph, results showed significant differences in movement initiation and backswing duration between serves received from a ball machine and serves received from a real server. Players had shorter movement initiation when they faced a ball machine. Backswing duration was longer for the group using a ball machine. That demonstrates different movement timing of tennis returns when players face a ball machine. Use of ball machines in tennis practice should be limited as it may disrupt stroke timing. Key pointsPlayers have shorter initial move time when they are facing the ball machine.Using the ball machine results in different swing timing and movement coordination.The use of the ball machine should be limited.

Game movement demands and physical profiles of junior, senior and elite male and female rugby sevens players.

PubMed

Clarke, Anthea C; Anson, Judith M; Pyne, David B

2017-04-01

To inform recruitment, selection, training and testing of male and female rugby sevens players game running movement patterns and physical characteristics were quantified across junior, senior, and elite playing levels. Anthropometric and physical testing (40 m sprint, vertical jump, Yo-Yo IR1) occurred prior to players' national championships or international tournaments (n = 110 players), while game movements were obtained via GPS (n = 499 game files). The game movements of male players were similar across playing levels except for number of impacts >10 g which were 2 to 4-fold higher in elite (25.0 ± 11.2 impacts · game - 1 ; mean ± SD), than junior (6.3 ± 3.5) and senior (11.8 ± 6.6) players. In men, there were fewer substantial correlations between on- and off-field measures which may reflect similar physical attributes across playing levels, and that other (strength, technical or tactical) factors may better differentiate these players. In females, elite players had more favourable on- and off-field performance measures than juniors and seniors, with moderate to strong correlations between on- and off-field variables. Female players should benefit from additional fitness training, while male players need to balance fitness with other technical and tactical factors.

Novel speed test for evaluation of badminton-specific movements.

PubMed

Madsen, Christian M; Karlsen, Anders; Nybo, Lars

2015-05-01

In this study, we developed a novel badminton-specific speed test (BST). The test was designed to mimic match play. The test starts in the center of the court and consists of 5 maximal actions to sensors located in each of the 4 corners of the court. The 20 actions are performed in randomized order as dictated by computer screen shots displayed 1 second after completion of the previous action. We assessed day-to-day variation in elite players, and specificity of the test was evaluated by comparing 30-m sprint performance and time to complete the BST in 20 elite players, 21 skilled players, and 20 age-matched physical active subjects (non-badminton players). Sprint performance was similar across groups, whereas the elite players were significantly (p ≤ 0.05) faster in the BST (total test time: 32.3 ± 1.1 seconds; average: 1.6 seconds per action) than the skilled (34.1 ± 2.0 seconds) and non-badminton players (35.7 ± 1.7 seconds). Day-to-day coefficient of variation (CV) of the BST was 0.7% for the elite players, whereas CV for repeated tests on the same day was 1.7% for elite, 2.6% for skilled, and 2.5% for non-badminton players. On this basis, we suggest that the BST may be valuable for evaluation of short-term maximal movement speed in badminton players. Thus, the BST seems to be sport specific, as it may discriminate between groups (elite, less trained players, and non-badminton players) with similar sprinting performance, and the low test-retest variation may allow for using the BST to evaluate longitudinal changes, for example, training effects or seasonal variations.

Normative data for the Functional Movement Screen in male Gaelic field sports.

PubMed

Fox, Domhnaill; O'Malley, Edwenia; Blake, Catherine

2014-08-01

To determine normative values for the Functional Movement Screen (FMS) in Elite and Sub-Elite male Gaelic Football and Hurling players. A cross sectional study of functional movement in Gaelic games at Elite and Sub-Elite level. Players were video recorded completing the Functional Movement Screen Tool and scored post-test. Comparisons were analysed using Mann-Whitney U tests. Field testing in team gym facility and university biomechanics laboratory. A total of 62 players were tested. This consisted of 41 Hurling, and 21 Gaelic Football players. 30 of these participants were deemed Elite and 32 were deemed Sub-Elite. The mean age of the sample was 22.15 ± 3.02 years. Functional Movement Screen (FMS). The FMS mean score for the sample was 15.56 ± 1.46. The Elite group (15.8 ± 1.58) scored higher than the Sub-Elite group (15.34 ± 1.31) but there was no significant difference between groups. This study provides normative reference values for Gaelic Players. Elite Gaelic Players perform no better than a young, active population in the FMS indicating a potential problem with the FMS as a measure. Copyright © 2013 Elsevier Ltd. All rights reserved.

Positional demands of international rugby union: evaluation of player actions and movements.

PubMed

Quarrie, Kenneth L; Hopkins, Will G; Anthony, Mike J; Gill, Nicholas D

2013-07-01

In rugby union, published analyses of actions and movements of players during matches have been limited to small samples of games at regional or national level. To analyse movements and activities of players in international rugby union matches with a sample size sufficient to clearly delineate positional roles. Observational study. Actions of 763 players were coded from video recordings of 90 international matches played by the New Zealand national team (the All Blacks) from 2004 to 2010. Movements of players were coded for 27 of these matches via a semi-automated player-tracking system. Movements and activities of all players from both teams were coded. Cluster analysis of activities and time-motion variables produced five subgroups of forwards (props, hookers, locks, flankers, Number 8 forwards) and five subgroups of backs (scrum-half, fly-half, midfield backs, wings and fullbacks). Forwards sustained much higher contact loads per match than backs, via scrums, rucks, tackles and mauls. Mean distance covered per match ranged from 5400 to 6300m, with backs generally running further than forwards. There were marked differences between positional groups in the amount of distance covered at various speeds. The amount of play per match varies by position due to differences in rates at which players are substituted. The distance covered by players at relatively fast running speeds (in excess of 5ms(-1)) appears to be higher during international matches than when competing at lower levels of the professional game. The specific match demands for positional groups need to be considered when managing player workloads. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Functional Performance Among Active Female Soccer Players After Unilateral Primary Anterior Cruciate Ligament Reconstruction Compared With Knee-Healthy Controls.

PubMed

Fältström, Anne; Hägglund, Martin; Kvist, Joanna

2017-02-01

Good functional performance with limb symmetry is believed to be important to minimize the risk of injury after a return to pivoting and contact sports after anterior cruciate ligament reconstruction (ACLR). This study aimed to investigate any side-to-side limb differences in functional performance and movement asymmetries in female soccer players with a primary unilateral anterior cruciate ligament (ACL)-reconstructed knee and to compare these players with knee-healthy controls from the same soccer teams. Cross-sectional study; Level of evidence, 3. This study included 77 active female soccer players at a median of 18 months after ACLR (interquartile range [IQR], 14.5 months; range, 7-39 months) and 77 knee-healthy female soccer players. The mean age was 20.1 ± 2.3 years for players with an ACL-reconstructed knee and 19.5 ± 2.2 years for controls. We used a battery of tests to assess postural control (Star Excursion Balance Test) and hop performance (1-legged hop for distance, 5-jump test, and side hop). Movement asymmetries in the lower limbs and trunk were assessed with the drop vertical jump and the tuck jump using 2-dimensional analyses. The reconstructed and uninvolved limbs did not differ in any of the tests. In the 5-jump test, players with an ACL-reconstructed knee performed worse than controls (mean 8.75 ± 1.05 m vs 9.09 ± 0.89 m; P = .034). On the drop vertical jump test, the ACL-reconstructed limb had significantly less knee valgus motion in the frontal plane (median 0.028 m [IQR, 0.049 m] vs 0.045 m [IQR, 0.043 m]; P = .004) and a lower probability of a high knee abduction moment (pKAM) (median 69.2% [IQR, 44.4%] vs 79.8% [IQR, 44.8%]; P = .043) compared with the control players' matched limb (for leg dominance). Results showed that 9% to 49% of players in both groups performed outside recommended guidelines on the different tests. Only 14 players with an ACL-reconstructed knee (18%) and 15 controls (19%) had results that met the recommended guidelines for all 5 tests ( P = .837). The reconstructed and uninvolved limbs did not differ, and players with an ACL-reconstructed knee and controls differed only minimally on the functional performance tests, indicating similar function. It is worth noting that many players with an ACL-reconstructed knee and controls had movement asymmetries and a high pKAM pattern, which have previously been associated with an increased risk for both primary and secondary ACL injury in female athletes.

Movement variability and skill level of various throwing techniques.

PubMed

Wagner, Herbert; Pfusterschmied, Jürgen; Klous, Miriam; von Duvillard, Serge P; Müller, Erich

2012-02-01

In team-handball, skilled athletes are able to adapt to different game situations that may lead to differences in movement variability. Whether movement variability affects the performance of a team-handball throw and is affected by different skill levels or throwing techniques has not yet been demonstrated. Consequently, the aims of the study were to determine differences in performance and movement variability for several throwing techniques in different phases of the throwing movement, and of different skill levels. Twenty-four team-handball players of different skill levels (n=8) performed 30 throws using various throwing techniques. Upper body kinematics was measured via an 8 camera Vicon motion capture system and movement variability was calculated. Results indicated an increase in movement variability in the distal joint movements during the acceleration phase. In addition, there was a decrease in movement variability in highly skilled and skilled players in the standing throw with run-up, which indicated an increase in the ball release speed, which was highest when using this throwing technique. We assert that team-handball players had the ability to compensate an increase in movement variability in the acceleration phase to throw accurately, and skilled players were able to control the movement, although movement variability decreased in the standing throw with run-up. Copyright © 2011 Elsevier B.V. All rights reserved.

The reliability and validity of subjective notational analysis in comparison to global positioning system tracking to assess athlete movement patterns.

PubMed

Doğramac, Sera N; Watsford, Mark L; Murphy, Aron J

2011-03-01

Subjective notational analysis can be used to track players and analyse movement patterns during match-play of team sports such as futsal. The purpose of this study was to establish the validity and reliability of the Event Recorder for subjective notational analysis. A course was designed, replicating ten minutes of futsal match-play movement patterns, where ten participants undertook the course. The course allowed a comparison of data derived from subjective notational analysis, to the known distances of the course, and to GPS data. The study analysed six locomotor activity categories, focusing on total distance covered, total duration of activities and total frequency of activities. The values between the known measurements and the Event Recorder were similar, whereas the majority of significant differences were found between the Event Recorder and GPS values. The reliability of subjective notational analysis was established with all ten participants being analysed on two occasions, as well as analysing five random futsal players twice during match-play. Subjective notational analysis is a valid and reliable method of tracking player movements, and may be a preferred and more effective method than GPS, particularly for indoor sports such as futsal, and field sports where short distances and changes in direction are observed.

RELATIONSHIP OF PRESEASON MOVEMENT SCREENS WITH OVERUSE SYMPTOMS IN COLLEGIATE BASEBALL PLAYERS

PubMed Central

Clifton, Daniel R.; Onate, James A.; Ramsey, Vincent K.; Cromartie, Fred

2017-01-01

Background: The shoulder mobility screen of the Functional Movement Screen™ (FMS™) and the upper extremity patterns of the Selective Functional Movement Assessment (SFMA) assess global, multi-joint movement capabilities in the upper-extremities. Identifying which assessment can most accurately determine if baseball players are at an increased risk of experiencing overuse symptoms in the shoulder or elbow throughout a competitive season may reduce throwing-related injuries requiring medical attention. Purpose: The purpose of this study was to determine if preseason FMS™ or SFMA scores were related to overuse severity scores in the shoulder or elbow during the preseason and competitive season. Study design: Cohort study. Methods: Sixty healthy, male, Division III collegiate baseball players (mean age = 20.1 ± 2.0 years) underwent preseason testing using the FMS™ shoulder mobility screen, and SFMA upper extremity patterns. Their scores were dichotomized into good and bad movement scores, and were compared to weekly questionnaires registering overuse symptoms and pain severity in the shoulder or elbow during the season. Results: Poor FMS™ performance was associated with an increased likelihood of experiencing at least one overuse symptom during the preseason independent of grade and position (adjusted odds ratio [OR] = 5.14, p = 0.03). Poor SFMA performance was associated with an increased likelihood of experiencing at least one overuse symptom during the preseason (adjusted OR = 6.10, p = 0.03) and during the competitive season (adjusted OR = 17.07, p = 0.03) independent of grade and position. Conclusion: FMS™ shoulder mobility and SFMA upper extremity pattern performance were related to the likelihood of experiencing overuse symptoms during a baseball season. Participants with poor FMSTM performances may be more likely to experience at least one overuse symptom in their shoulder or elbow during the preseason. Additionally, individuals with poor SFMA performances may be more likely to report overuse symptoms during the preseason or competitive season. Level of evidence: Level 3 PMID:29158957

Strength Determinants of Jump Height in the Jump Throw Movement in Women Handball Players.

PubMed

McGhie, David; Østerås, Sindre; Ettema, Gertjan; Paulsen, Gøran; Sandbakk, Øyvind

2018-06-08

McGhie, D, Østerås, S, Ettema, G, Paulsen, G, and Sandbakk, Ø. Strength determinants of jump height in the jump throw movement in women handball players. J Strength Cond Res XX(X): 000-000, 2018-The purpose of the study was to improve the understanding of the strength demands of a handball-specific jump through examining the associations between jump height in a jump throw jump (JTJ) and measures of lower-body maximum strength and impulse in handball players. For comparison, whether the associations between jump height and strength differed between the JTJ and the customarily used countermovement jump (CMJ) was also examined. Twenty women handball players from a Norwegian top division club participated in the study. Jump height was measured in the JTJ and in unilateral and bilateral CMJ. Lower-body strength (maximum isometric force, one-repetition maximum [1RM], impulse at ∼60% and ∼35% 1RM) was measured in seated leg press. The associations between jump height and strength were assessed with correlation analyses and t-tests of dependent r's were performed to determine if correlations differed between jump tests. Only impulse at ∼35% 1RM correlated significantly with JTJ height (p < 0.05), whereas all strength measures correlated significantly with CMJ heights (p < 0.001). The associations between jump height and strength were significantly weaker in the JTJ than in both CMJ tests for all strength measures (p = 0.001-0.044) except one. Maximum strength and impulse at ∼60% 1RM did not seem to sufficiently capture the capabilities associated with JTJ height, highlighting the importance of employing tests targeting performance-relevant neuromuscular characteristics when assessing jump-related strength in handball players. Further, CMJ height seemed to represent a wider range of strength capabilities and care should be taken when using it as a proxy for handball-specific movements.

The test-retest reliability and criterion validity of a high-intensity, netball-specific circuit test: The Net-Test.

PubMed

Mungovan, Sean F; Peralta, Paula J; Gass, Gregory C; Scanlan, Aaron T

2018-04-12

To examine the test-retest reliability and criterion validity of a high-intensity, netball-specific fitness test. Repeated measures, within-subject design. Eighteen female netball players competing in an international competition completed a trial of the Net-Test, which consists of 14 timed netball-specific movements. Players also completed a series of netball-relevant criterion fitness tests. Ten players completed an additional Net-Test trial one week later to assess test-retest reliability using intraclass correlation coefficient (ICC), typical error of measurement (TEM), and coefficient of variation (CV). The typical error of estimate expressed as CV and Pearson correlations were calculated between each criterion test and Net-Test performance to assess criterion validity. Five movements during the Net-Test displayed moderate ICC (0.84-0.90) and two movements displayed high ICC (0.91-0.93). Seven movements and heart rate taken during the Net-Test held low CV (<5%) with values ranging from 1.7 to 9.5% across measures. Total time (41.63±2.05s) during the Net-Test possessed low CV and significant (p<0.05) correlations with 10m sprint time (1.98±0.12s; CV=4.4%, r=0.72), 20m sprint time (3.38±0.19s; CV=3.9%, r=0.79), 505 Change-of-Direction time (2.47±0.08s; CV=2.0%, r=0.80); and maximum oxygen uptake (46.59±2.58 mLkg -1 min -1 ; CV=4.5%, r=-0.66). The Net-Test possesses acceptable reliability for the assessment of netball fitness. Further, the high criterion validity for the Net-Test suggests a range of important netball-specific fitness elements are assessed in combination. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Acute motor, neurocognitive and neurophysiological change following concussion injury in Australian amateur football. A prospective multimodal investigation.

PubMed

Pearce, Alan J; Hoy, Kate; Rogers, Mark A; Corp, Daniel T; Davies, Charlotte B; Maller, Jerome J; Fitzgerald, Paul B

2015-09-01

This multimodal study investigated the motor, neurocognitive and neurophysiological responses following a sports related concussion injury in the acute-phase (up to 10 days) in sub-elite Australian football players. Between-group, repeated measures. Over the course of one season (six months), 43 male players from one football club (25.1 ± 4.5 years) were assessed for fine motor dexterity, visuomotor reaction time, implicit learning and attention. Motor cortex excitability and inhibition were assessed using transcranial magnetic stimulation. Of the 43 players, eight suffered concussion injuries, and were compared to 15 non-concussed players (active control) who returned for follow up testing. Post-concussion assessments using the aforementioned tests were carried out at 48 and 96 h, and 10 days. Compared to the non-concussed players, those who suffered concussion showed slowed fine dexterity (P = 0.02), response (P = 0.02) and movement times (P = 0.01) 48 h post-concussion. Similarly, attentional performance was reduced in the concussed group at all time points (48 h: P < 0.01; 96 h: P < 0.01; and 10 days: P = 0.02) post-concussion. TMS revealed significantly increased corticospinal inhibition at 48 (P = 0.04) and 96 h post concussion (P = 0.02) with significant correlations between increased corticospinal inhibition and response (r = 0.48; P < 0.01), movement time (r = 0.42; P = 0.02), and attention performance (r = 0.44; P = 0.01). This study has demonstrated that acutely concussed Australian football players show abnormalities in motor, cognitive and neurophysiological measures with variable rates of recovery. These findings suggest that measuring the recovery of concussed athletes should incorporate a range of testing modalities rather than relying on one area of measurement in determining return to play. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

The inter and intra rater reliability of the Netball Movement Screening Tool.

PubMed

Reid, Duncan A; Vanweerd, Rebecca J; Larmer, Peter J; Kingstone, Rachel

2015-05-01

To establish the inter- and intra-rater reliability of the Netball Movement Screening Tool, for screening adolescent female netball players. Inter- and intra-rater reliability study. Forty secondary school netball players were recruited to take part in the study. Twenty subjects were screened simultaneously and independently by two raters to ascertain inter-rater agreement. Twenty subjects were scored by rater one on two occasions, separated by a week, to ascertain intra-rater agreement. Inter and intra-rater agreement was assessed utilising the two-way mixed inter class correlation coefficient and weighted kappa statistics. No significant demographic differences were found between the inter and intra-rater groups of subjects. Inter class correlation coefficients' demonstrated excellent inter-rater (two-way mixed inter class correlation coefficients 0.84, standard error of measurement 0.25) and intra-rater (two-way mixed inter class correlation coefficients 0.96, standard error of measurement 0.13) reliability for the overall Netball Movement Screening Tool score and substantial-excellent (two-way mixed inter class correlation coefficients 1.0-0.65) inter-rater and substantial-excellent intra-rater (two-way mixed inter class correlation coefficients 0.96-0.79) reliability for the component scores of the Netball Movement Screening Tool. Kappa statistic showed substantial to poor inter-rater (k=0.75-0.32) and intra-rater (k=0.77-0.27) agreement for individual tests of the NMST. The Netball Movement Screening Tool may be a reliable screening tool for adolescent netball players; however the individual test scores have low reliability. The screening tool can be administered reliably by raters with similar levels of training in the tool but variable clinical experience. On-going research needs to be undertaken to ascertain whether the Netball Movement Screening Tool is a valid tool in ascertaining increased injury risk for netball players. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Scapular Resting Position and Gleno-Humeral Movement Dysfunction in Asymptomatic Racquet Players: A Case-Control Study

PubMed Central

Shimpi, Apurv P.; Bhakti, Shah; Roshni, Karnik; Rairikar, Savita A.; Shyam, Ashok; Sancheti, Parag K.

2015-01-01

Background: Racquet sports, especially lawn tennis and badminton have been gaining popularity in Asian countries like India. With this increase in popularity, the injury rate in the sport has also increased. Objectives: The study will help detect the presence of gleno-humeral movement dysfunction and scapular resting position abnormality in asymptomatic racquet players, thus providing basis for screening the players and allow the clinician to determine if the asymmetry is a normal adaptation in the player or an abnormal change associated with injury. Materials and Methods: 46 asymptomatic professional players were divided into a study group of 23 players (16 tennis and 7 badminton) and control group of 23 football players. Assessment of passive gleno-humeral range of motion and distance of spine and inferior angle of scapula from corresponding spinous process were measured bilaterally and between groups. Results: There was statistically significant reduction in range of internal rotation (62.17 ± 8.09), extension (39.78 ± 4.12) and an increase in the external rotation (106.95 ± 7.49) of dominant compared to non-dominant arm of racquet players and a statistically significant decrease in internal rotation (78.69 ± 10.24), extension (44.78 ± 3.19), adduction (37.39 ± 6.54) and an increase in external rotation (102.6 ± 5.19) of dominant arm of racquet players compared to football players. Study also showed statistically significant increase in the spino-scapular distance at the level of inferior angle of scapula (10.23 ± 1.43) on dominant side compared to non-dominant. Conclusions: The dominant side scapula of asymptomatic racquet players showed increased external rotation and elevation as compared to the non-dominant side. Also, reduced shoulder internal rotation, extension and adduction and gain in shoulder external rotation was observed on the dominant side of racquet players when compared to the control group. PMID:26715968

Scapular Resting Position and Gleno-Humeral Movement Dysfunction in Asymptomatic Racquet Players: A Case-Control Study.

PubMed

Shimpi, Apurv P; Bhakti, Shah; Roshni, Karnik; Rairikar, Savita A; Shyam, Ashok; Sancheti, Parag K

2015-12-01

Racquet sports, especially lawn tennis and badminton have been gaining popularity in Asian countries like India. With this increase in popularity, the injury rate in the sport has also increased. The study will help detect the presence of gleno-humeral movement dysfunction and scapular resting position abnormality in asymptomatic racquet players, thus providing basis for screening the players and allow the clinician to determine if the asymmetry is a normal adaptation in the player or an abnormal change associated with injury. 46 asymptomatic professional players were divided into a study group of 23 players (16 tennis and 7 badminton) and control group of 23 football players. Assessment of passive gleno-humeral range of motion and distance of spine and inferior angle of scapula from corresponding spinous process were measured bilaterally and between groups. There was statistically significant reduction in range of internal rotation (62.17 ± 8.09), extension (39.78 ± 4.12) and an increase in the external rotation (106.95 ± 7.49) of dominant compared to non-dominant arm of racquet players and a statistically significant decrease in internal rotation (78.69 ± 10.24), extension (44.78 ± 3.19), adduction (37.39 ± 6.54) and an increase in external rotation (102.6 ± 5.19) of dominant arm of racquet players compared to football players. Study also showed statistically significant increase in the spino-scapular distance at the level of inferior angle of scapula (10.23 ± 1.43) on dominant side compared to non-dominant. The dominant side scapula of asymptomatic racquet players showed increased external rotation and elevation as compared to the non-dominant side. Also, reduced shoulder internal rotation, extension and adduction and gain in shoulder external rotation was observed on the dominant side of racquet players when compared to the control group.

Construct Validity of Accelerometry-Derived Force to Quantify Basketball Movement Patterns.

PubMed

Staunton, Craig; Wundersitz, Daniel; Gordon, Brett; Kingsley, Michael

2017-12-01

This study assessed the construct validity of accelerometry-derived net force to quantify the external demands of basketball movements. Twenty-eight basketballers completed the Yo-Yo intermittent recovery test (Yo-Yo-IR1) and basketball exercise simulation test (BEST). Intensity was quantified using accelerometry-derived average net force (AvF Net ) and PlayerLoad TM per minute (PL/min). Within-player correlations were determined between intensity and running speed during Yo-Yo-IR1. Measured AvF Net was determined for movements during the BEST and predicted AvF Net was calculated using movement speed and correlations from Yo-Yo-IR1. Relationships between AvF Net and running speed during Yo-Yo-IR1 were nearly perfect (r 2 =0.95, 95% CI: 0.94-0.96; p<0.001) and stronger than correlations between running speed and PL/min (r 2 =0.80, 95% CI: 0.73-0.87; p<0.001). Differences between measured and predicted AvF Net were small during jogging and running (<1%), but large for basketball movements including jumping, change-of-direction and shuffling (15%-41%). As hypothesised, AvF Net differed by playing position (11%-16%; p <0.001) and reflected the additional demand upon players with larger body mass and lower movement efficiency. Both sprint speed and AvF Net reduced during the course of the BEST ( p ≤0.013). These findings confirm the construct validity of AvF Net to quantify the external demand of basketball movements. Accelerometry-derived net force has the potential to quantify the external demands of basketballers during training and competition. © Georg Thieme Verlag KG Stuttgart · New York.

Morphological, motor and situation-motor characteristics of elite female handball players according to playing performance and position.

PubMed

Cavala, Marijana; Katić, Ratko

2010-12-01

The aim of the study was to define biomotor characteristics that determine playing performance and position in female handball. A battery of 13 variables consisting of somatotype components (3 variables), basic motor abilities (5 variables) and specific motor abilities (5 variables) were applied in a sample of 52 elite female handball players. Differences in biomotor characteristics according to playing performance and position of female handball players were determined by use of the analysis of variance (ANOVA) and discriminative analysis. Study results showed the high-quality female handball players to predominantly differ from the less successful ones in the specific factor of throw strength and basic dash factor, followed by the specific abilities of movement without and with ball, basic coordination/agility and specific ability of ball manipulation, and a more pronounced mesomorphic component. Results also revealed the wing players to be superior in the speed of movement frequency (psychomotor speed), run (explosive strength) and speed of movement with ball as compared with players at other playing positions. Also, endomorphic component was less pronounced in players at the wing and back player positions as compared with goalkeeper and pivot positions, where endomorphic component was considerably more pronounced.

The development of aerobic and skill assessment in soccer.

PubMed

O'Reilly, John; Wong, Stephen H S

2012-12-01

Methods of assessing soccer players' performance have developed significantly in recent times. The fitness profiles and skill levels of a prospective elite soccer player is a valuable resource for coaches in the process of identifying talent. Traditional means to measure aerobic fitness have centred on the 'aerobic capacity' or '&OV0312;O(2max)' test (also known as the maximal oxygen consumption test) but, over time, this has been shown not to be a sensitive measure for specific aspects of soccer in a match situation. Therefore, numerous soccer-specific simulations have been designed to re-create exercise patterns similar to those experienced during a match. Some of these studies have yet to be validated, while others have been shown to result in a similar physiological load to that encountered during regular match play. Further developments have led to specifically designed intermittent sprint tests, which are used as a sensitive tool to accurately measure the fluctuations in players' ability both between and within soccer seasons. Testing procedures have also been developed that incorporate elements of both skill and physical ability. Soccer-specific field tests have been designed, incorporating skill and dynamic movements, and this opens up the possibility of teams testing the aerobic capacity of their elite players using soccer-specific movements. Valid studies assessing soccer-specific skills in an ecologically sound environment have been quite rare until recently. Some test protocols have been deemed largely irrelevant to soccer match play, while others have had limited impact on scientific literature. More recently, skill tests have been developed and shown to be valid and reliable methods of assessing soccer skill performance. Many new skill tests continue to be developed, and some have been shown to be highly reliable, but further study of these relatively novel concepts is required before a more solid recommendation can be made. Overall, while significant work has been completed to date, there is still a need for further focused investigations, which can more closely assess the physiological demands of an elite soccer player, with a particular emphasis on sport-specific exercises during the execution of soccer skills. In this regard, more reliable and specific performance tests can be designed to more efficiently assess soccer players in the future.

Comparison of global positioning and computer-based tracking systems for measuring player movement distance during Australian football.

PubMed

Edgecomb, S J; Norton, K I

2006-05-01

Sports scientists require a thorough understanding of the energy demands of sports and physical activities so that optimal training strategies and game simulations can be constructed. A range of techniques has been used to both directly assess and estimate the physiological and biochemical changes during competition. A fundamental approach to understanding the contribution of the energy systems in physical activity has involved the use of time-motion studies. A number of tools have been used from simple pen and paper methods, the use of video recordings, to sophisticated electronic tracking devices. Depending on the sport, there may be difficulties in using electronic tracking devices because of concerns of player safety. This paper assesses two methods currently used to measure player movement patterns during competition: (1) global positioning technology (GPS) and (2) a computer-based tracking (CBT) system that relies on a calibrated miniaturised playing field and mechanical movements of the tracker. A range of ways was used to determine the validity and reliability of these methods for tracking Australian footballers for distance covered during games. Comparisons were also made between these methods. The results indicate distances measured using CBT overestimated the actual values (measured with a calibrated trundle wheel) by an average of about 5.8%. The GPS system overestimated the actual values by about 4.8%. Distances measured using CBT in experienced hands were as accurate as the GPS technology. Both systems showed relatively small errors in true distances.

The appropriateness of training exposures for match-play preparation in adolescent schoolboy and academy rugby union players.

PubMed

Phibbs, Padraic J; Jones, Ben; Read, Dale B; Roe, Gregory A B; Darrall-Jones, Joshua; Weakley, Jonathon J S; Rock, Andrew; Till, Kevin

2018-03-01

The aim of this study was to compare the physical and movement demands between training and match-play in schoolboy and academy adolescent rugby union (RU) players. Sixty-one adolescent male RU players (mean ± SD; age 17.0 ± 0.7 years) were recruited from four teams representing school and regional academy standards. Players were categorised into four groups based on playing standard and position: schoolboy forwards (n = 15), schoolboy backs (n = 15), academy forwards (n = 16) and academy backs (n = 15). Global positioning system and accelerometry measures were obtained from training and match-play to assess within-group differences between conditions. Maximum data were analysed from 79 match files across 8 matches (1.3 ± 0.5 matches per participant) and 152 training files across 15 training sessions (2.5 ± 0.5 training sessions per participant). Schoolboy forwards were underprepared for low-intensity activities experienced during match-play, with schoolboy backs underprepared for all movement demands. Academy forwards were exposed to similar physical demands in training to matches, with academy backs similar to or exceeding values for all measured variables. Schoolboy players were underprepared for many key, position-specific aspects of match-play, which could place them at greater risk of injury and hinder performance, unlike academy players who were better prepared.

The Effect of Eight Weeks Plyometric Training on Anaerobic Power, Counter Movement Jumping and Isokinetic Strength in 15-18 Years Basketball Players

ERIC Educational Resources Information Center

Adigüzel, Niyazi Sidki; Günay, Mehmet

2016-01-01

The purpose of this study was to investigate the effect of eight weeks plyometric training on anaerobic power, counter movement jumping and isokinetic strength in 15-18 years aged basketball players. This study was including 30 male Basketball players. The subjects were divided into two groups as: the experimental group (n = 15) and the control…

Preseason Functional Movement Screen Component Tests Predict Severe Contact Injuries in Professional Rugby Union Players.

PubMed

Tee, Jason C; Klingbiel, Jannie F G; Collins, Robert; Lambert, Mike I; Coopoo, Yoga

2016-11-01

Tee, JC, Klingbiel, JFG, Collins, R, Lambert, MI, and Coopoo, Y. Preseason Functional Movement Screen component tests predict severe contact injuries in professional rugby union players. J Strength Cond Res 30(11): 3194-3203, 2016-Rugby union is a collision sport with a relatively high risk of injury. The ability of the Functional Movement Screen (FMS) or its component tests to predict the occurrence of severe (≥28 days) injuries in professional players was assessed. Ninety FMS test observations from 62 players across 4 different time periods were compared with severe injuries sustained during 6 months after FMS testing. Mean composite FMS scores were significantly lower in players who sustained severe injury (injured 13.2 ± 1.5 vs. noninjured 14.5 ± 1.4, Effect Size = 0.83, large) because of differences in in-line lunge (ILL) and active straight leg raise scores (ASLR). Receiver-operated characteristic curves and 2 × 2 contingency tables were used to determine that ASLR (cut-off 2/3) was the injury predictor with the greatest sensitivity (0.96, 95% confidence interval [CI] = 0.79-1.0). Adding the ILL in combination with ASLR (ILL + ASLR) improved the specificity of the injury prediction model (ASLR specificity = 0.29, 95% CI = 0.18-0.43 vs. ASLR + ILL specificity = 0.53, 95% CI = 0.39-0.66, p ≤ 0.05). Further analysis was performed to determine whether FMS tests could predict contact and noncontact injuries. The FMS composite score and various combinations of component tests (deep squat [DS] + ILL, ILL + ASLR, and DS + ILL + ASLR) were all significant predictors of contact injury. The FMS composite score also predicted noncontact injury, but no component test or combination thereof produced a similar result. These findings indicate that low scores on various FMS component tests are risk factors for injury in professional rugby players.

A Critical Interpersonal Distance Switches between Two Coordination Modes in Kendo Matches

PubMed Central

Okumura, Motoki; Kijima, Akifumi; Kadota, Koji; Yokoyama, Keiko; Suzuki, Hiroo; Yamamoto, Yuji

2012-01-01

In many competitive sports, players need to quickly and continuously execute movements that co-adapt to various movements executed by their opponents and physical objects. In a martial art such as kendo, players must be able to skillfully change interpersonal distance in order to win. However, very little information about the task and expertise properties of the maneuvers affecting interpersonal distance is available. This study investigated behavioral dynamics underlying opponent tasks by analyzing changes in interpersonal distance made by expert players in kendo matches. Analysis of preferred interpersonal distances indicated that players tended to step toward and away from their opponents based on two distances. The most preferred distance enabled the players to execute both striking and defensive movements immediately. The relative phase analysis of the velocities at which players executed steps toward and away revealed that players developed anti-phase synchronizations at near distances to maintain safe distances from their opponents. Alternatively, players shifted to in-phase synchronization to approach their opponents from far distances. This abrupt phase-transition phenomenon constitutes a characteristic bifurcation dynamics that regularly and instantaneously occurs between in- and anti-phase synchronizations at a critical interpersonal distance. These dynamics are profoundly affected by the task constraints of kendo and the physical constraints of the players. Thus, the current study identifies the clear behavioral dynamics that emerge in a sport setting. PMID:23284799

Planning abilities and chess: a comparison of chess and non-chess players on the Tower of London task.

PubMed

Unterrainer, J M; Kaller, C P; Halsband, U; Rahm, B

2006-08-01

Playing chess requires problem-solving capacities in order to search through the chess problem space in an effective manner. Chess should thus require planning abilities for calculating many moves ahead. Therefore, we asked whether chess players are better problem solvers than non-chess players in a complex planning task. We compared planning performance between chess ( N=25) and non-chess players ( N=25) using a standard psychometric planning task, the Tower of London (ToL) test. We also assessed fluid intelligence (Raven Test), as well as verbal and visuospatial working memory. As expected, chess players showed better planning performance than non-chess players, an effect most strongly expressed in difficult problems. On the other hand, they showed longer planning and movement execution times, especially for incorrectly solved trials. No differences in fluid intelligence and verbal/visuospatial working memory were found between both groups. These findings indicate that better performance in chess players is associated with disproportionally longer solution times, although it remains to be investigated whether motivational or strategic differences account for this result.

Bring It to the Pitch: Combining Video and Movement Data to Enhance Team Sport Analysis.

PubMed

Stein, Manuel; Janetzko, Halldor; Lamprecht, Andreas; Breitkreutz, Thorsten; Zimmermann, Philipp; Goldlucke, Bastian; Schreck, Tobias; Andrienko, Gennady; Grossniklaus, Michael; Keim, Daniel A

2018-01-01

Analysts in professional team sport regularly perform analysis to gain strategic and tactical insights into player and team behavior. Goals of team sport analysis regularly include identification of weaknesses of opposing teams, or assessing performance and improvement potential of a coached team. Current analysis workflows are typically based on the analysis of team videos. Also, analysts can rely on techniques from Information Visualization, to depict e.g., player or ball trajectories. However, video analysis is typically a time-consuming process, where the analyst needs to memorize and annotate scenes. In contrast, visualization typically relies on an abstract data model, often using abstract visual mappings, and is not directly linked to the observed movement context anymore. We propose a visual analytics system that tightly integrates team sport video recordings with abstract visualization of underlying trajectory data. We apply appropriate computer vision techniques to extract trajectory data from video input. Furthermore, we apply advanced trajectory and movement analysis techniques to derive relevant team sport analytic measures for region, event and player analysis in the case of soccer analysis. Our system seamlessly integrates video and visualization modalities, enabling analysts to draw on the advantages of both analysis forms. Several expert studies conducted with team sport analysts indicate the effectiveness of our integrated approach.

Evaluation of Functional Limitations in Female Soccer Players and Their Relationship with Sports Level – A Cross Sectional Study

PubMed Central

Grygorowicz, Monika; Piontek, Tomasz; Dudzinski, Witold

2013-01-01

The main objective(s) of the study The aim of this study was to analyze: a) abnormalities in the length of lower limb muscles, b) the correctness of movement patterns, and c) the impact of functional limitations of muscles on the correctness of fundamental movement patterns in a group of female soccer players, in relation to their skill level. Materials and Methods 21 female soccer players from Polish Ekstraklasa and 22 players from the 1st Division were tested for lower limb muscle length restrictions and level of fundamental movement skills (with the Fundamental Movement Screen™ test concept by Gray Cook). Chi-square test was used for categorical unrelated variables. Differences between groups in absolute point values were analyzed using the non-parametric Mann-Whitney U test. Statistical significance was set at p<0.05. Results Statistically significant higher number of measurements indicating an abnormal length of rectus femoris was observed in the 1st Division group (p = 0.0433). In the group of Ekstraklasa the authors obtained a significantly higher number of abnormal hamstring test results (p = 0.0006). Ekstraklasa players scored higher in the rotational stability test of the trunk (p = 0.0008), whereas the 1st Division players scored higher in the following tests: deep squat (p = 0.0220), in-line lunge (p = 0.0042) and active straight leg raise (p = 0.0125). The results suggest that there are different functional reasons affecting point values obtained in the FMS™ tests in both analyzed groups. Conclusions The differences in the flexibility of rectus femoris and hamstring muscle observed between female soccer players with different levels of training, may result from a long-term impact of soccer training on the muscle-tendon system and articular structures. Different causes of abnormalities in fundamental movement patterns in both analyzed groups suggest the need for tailoring prevention programs to the level of sport skills represented by the players. PMID:23825579

Performance and Kinematics of Various Throwing Techniques in Team-Handball

PubMed Central

Wagner, Herbert; Pfusterschmied, Jürgen; von Duvillard, Serge P.; Müller, Erich

2011-01-01

In team-handball competition, the players utilize various throwing techniques that differ in the lower body movements (with and without run-up or jump). These different lower body movements influence changes in the upper body movements and thus also affect the performance. A comprehensive analysis of 3D-kinematics of team-handball throws that may explain these differences in performance is lacking. Consequently, the purpose of this study was (1) to compare performance (ball velocity and throwing accuracy) between the jump throw, standing throw with and without run-up, and the pivot throw; (2) to calculate the influence of kinematic parameters to ball velocity; and (3) to determine if these four throwing techniques differ significantly in kinematics. Three-dimensional kinematic data (angles, angular velocities and their timing, ball velocity and velocity of the center of mass) of 14 elite team-handball players were measured using an 8 camera Vicon MX13 motion capture system (Vicon, Oxford, UK), at 250 Hz. Significant difference was found between the four throwing techniques for ball velocity (p < 0. 001), maximal velocity of the center of mass in goal-directed movement (p < 0.001), and 15 additional kinematic variables (p < 0.003). Ball velocity was significant impacted by the run-up and the pelvis and trunk movements. Depending on floor contact (standing vs. jump throws), elite players in the study used two different strategies (lead leg braces the body vs. opposed leg movements during flight) to accelerate the pelvis and trunk to yield differences in ball velocity. However, these players were able to utilize the throwing arm similarly in all four throwing techniques. Key points Elite team-handball players achieved the greatest ball velocity in the standing throw with run-up (100%), followed by the standing throw without run-up (93%), jump throw (92%) and pivot throw (85%). Depending on the floor contact (standing vs. jump throws) the elite players of the study used two different strategies (lead leg braces the body vs. opposed leg movements during flight) to accelerate the pelvis and trunk that caused differences in ball velocity. Elite team-handball players were able to utilize the throwing arm similarly in all four throwing techniques. PMID:24149298

Time-motion analysis of goalball players in attacks: differences of the player positions and the throwing techniques.

PubMed

Monezi, Lucas Antônio; Magalhães, Thiago Pinguelli; Morato, Márcio Pereira; Mercadante, Luciano Allegretti; Furtado, Otávio Luis Piva da Cunha; Misuta, Milton Shoiti

2018-03-26

In this study, we aimed to analyse goalball players time-motion variables (distance covered, time spent, maximum and average velocities) in official goalball match attacks, taking into account the attack phases (preparation and throwing), player position (centres and wings) and throwing techniques (frontal, spin and between the legs). A total of 365 attacks were assessed using a video based method (2D) through manual tracking using the Dvideo system. Inferential non-parametric statistics were applied for comparison of preparation vs. throwing phase, wings vs. centres and, among the throwing techniques, frontal, spin and between the legs. Significant differences were found between the attack preparation versus the throwing phase for all player time-motion variables: distance covered, time spent, maximum player velocity and average player velocity. Wing players performed most of the throws (85%) and covered longer distances than centres (1.65 vs 0.31 m). The between the legs and the spin throwing techniques presented greater values for most of the time-motion variables (distance covered, time spent and maximum player velocity) than did the frontal technique in both attack phases. These findings provide important information regarding players' movement patterns during goalball matches that can be used to plan more effective training.

The physical characteristics of match-play in English schoolboy and academy rugby union.

PubMed

Read, Dale B; Jones, Ben; Phibbs, Padraic J; Roe, Gregory A B; Darrall-Jones, Joshua; Weakley, Jonathon J S; Till, Kevin

2018-03-01

The aim was to compare the physical characteristics of under-18 academy and schoolboy rugby union competition by position (forwards and backs). Using a microsensor unit, match characteristics were recorded in 66 players. Locomotor characteristics were assessed by maximum sprint speed (MSS) and total, walking, jogging, striding and sprinting distances. The slow component (<2 m · s -1 ) of PlayerLoad TM (PL slow ), which is the accumulated accelerations from the three axes of movement, was analysed as a measure of low-speed activity (e.g., rucking). A linear mixed-model was assessed with magnitude-based inferences. Academy forwards and backs almost certainly and very likely covered greater total distance than school forwards and backs. Academy players from both positions were also very likely to cover greater jogging distances. Academy backs were very likely to accumulate greater PL slow and the academy forwards a likely greater sprinting distance than school players in their respective positions. The MSS, total, walking and sprinting distances were greater in backs (likely-almost certainly), while forwards accumulated greater PL slow (almost certainly) and jogging distance (very likely). The results suggest that academy-standard rugby better prepares players to progress to senior competition compared to schoolboy rugby.

Movement and physical demands of school and university rugby union match-play in England

PubMed Central

Read, Dale; Weaving, Daniel; Phibbs, Padraic; Darrall-Jones, Joshua; Roe, Gregory; Weakley, Jonathon; Hendricks, Sharief; Till, Kevin; Jones, Ben

2017-01-01

Background In England, rugby union is a popular sport and is widely played within schools. Despite the large participation numbers, the movement and physical demands of the sport and how they progress by age have not been explored. Method Ninety-six male rugby union players wore microtechnology devices during six rugby union matches within the education pathway to investigate the movement and physical demands of match-play. To quantify the positional differences and progression by age, data were obtained for participants at the under 16 (U16) (n=31 participants), under 18 (U18) (n=34 participants) and university (n=31 participants) levels. Players were further divided in forwards and backs. Data were analysed using magnitude-based inferences. Results For the movement demands, U16 total distance and ‘striding’ was likely higher for forwards than backs, whereas at U18, unclear differences were observed and from university players the inverse was observed (very likely). In all age groups sprint distance was likely to very likely greater for backs than forwards. Forwards had greater physical demands than backs at all age groups. For consecutive age groups, U16 had a likely higher relative distance than U18, and U18 had a likely lower relative distance than university players. Physical demands were similar across age groups for forwards, and greater for backs at older age groups. Conclusion The movement and physical demands of rugby union players participating in schools (U16 and U18), may not be as expected, however, the findings from university players show a similar pattern to the senior game. PMID:28879027

Movement and physical demands of school and university rugby union match-play in England.

PubMed

Read, Dale; Weaving, Daniel; Phibbs, Padraic; Darrall-Jones, Joshua; Roe, Gregory; Weakley, Jonathon; Hendricks, Sharief; Till, Kevin; Jones, Ben

2016-01-01

In England, rugby union is a popular sport and is widely played within schools. Despite the large participation numbers, the movement and physical demands of the sport and how they progress by age have not been explored. Ninety-six male rugby union players wore microtechnology devices during six rugby union matches within the education pathway to investigate the movement and physical demands of match-play. To quantify the positional differences and progression by age, data were obtained for participants at the under 16 (U16) (n=31 participants), under 18 (U18) (n=34 participants) and university (n=31 participants) levels. Players were further divided in forwards and backs. Data were analysed using magnitude-based inferences. For the movement demands, U16 total distance and 'striding' was likely higher for forwards than backs, whereas at U18, unclear differences were observed and from university players the inverse was observed (very likely). In all age groups sprint distance was likely to very likely greater for backs than forwards. Forwards had greater physical demands than backs at all age groups. For consecutive age groups, U16 had a likely higher relative distance than U18, and U18 had a likely lower relative distance than university players. Physical demands were similar across age groups for forwards, and greater for backs at older age groups. The movement and physical demands of rugby union players participating in schools (U16 and U18), may not be as expected, however, the findings from university players show a similar pattern to the senior game.

A Practice Indexes for Improving Facial Movements of Brass Instrument Players

NASA Astrophysics Data System (ADS)

Ito, Kyoko; Hirano, Takeshi; Noto, Kazufumi; Nishida, Shogo; Ohtsuki, Tatsuyuki

Two experimental studies have been conducted in order to propose practice indexes for the improvement of the embouchure of French horn players, two experimental studies have been conducted. In both studies, the same task was performed by advanced and amateur French horn players. The first study investigated the activity, while performing the above-mentioned task, of the 5 facial muscles (levator labii superioris, zygomaticus major, depressor anguli oris, depressor labii inferioris, and risorius muscles) on the right side of the face by surface electromyography, and the facial movement on the left side of the face by attaching two markers above each muscle and using two high-speed cameras simultaneously. The results of the study showed that it is possible for the four markers around the lower lip to practice indexes. The second study evaluated whether the above-mentioned markers are appropriate as practice indexes using a 3-D tracking system and questionnaires. The results showed that both the advanced and the amateur players assessed that the markers were suitable as practice indexes for improving the embouchure. This set of approaches could be useful for selecting practice indexes and developing scientific practice methods not only for the French horn but also for other instruments and other fields.

The Musculoskeletal Readiness Screening Tool-Injury Predictor for United States Military Academy Preparatory Cadets

DTIC Science & Technology

2015-10-30

predictors of ACL injury.25 189 Several studies investigate the effects of faulty movement and injury 190 prediction for the lower extremity. In 2006...at 40% and 39% of the total injuries, respectively.16 In 2012, 83 193 NCAA Division I football players participated in a survey to assess low back...recent study , firefighters performed the FMS™ and firefighter-specific testing. Two 218 of the musculoskeletal movement variables were predictive of

Prediction of shot success for basketball free throws: visual search strategy.

PubMed

Uchida, Yusuke; Mizuguchi, Nobuaki; Honda, Masaaki; Kanosue, Kazuyuki

2014-01-01

In ball games, players have to pay close attention to visual information in order to predict the movements of both the opponents and the ball. Previous studies have indicated that players primarily utilise cues concerning the ball and opponents' body motion. The information acquired must be effective for observing players to select the subsequent action. The present study evaluated the effects of changes in the video replay speed on the spatial visual search strategy and ability to predict free throw success. We compared eye movements made while observing a basketball free throw by novices and experienced basketball players. Correct response rates were close to chance (50%) at all video speeds for the novices. The correct response rate of experienced players was significantly above chance (and significantly above that of the novices) at the normal speed, but was not different from chance at both slow and fast speeds. Experienced players gazed more on the lower part of the player's body when viewing a normal speed video than the novices. The players likely detected critical visual information to predict shot success by properly moving their gaze according to the shooter's movements. This pattern did not change when the video speed was decreased, but changed when it was increased. These findings suggest that temporal information is important for predicting action outcomes and that such outcomes are sensitive to video speed.

Pattern recall skills of talented soccer players: Two new methods applied.

PubMed

van Maarseveen, Mariëtte J J; Oudejans, Raôul R D; Savelsbergh, Geert J P

2015-06-01

In this study we analyzed the pattern recall skills of talented soccer players by means of two innovative methods of analysis and gaze behavior data. Twenty-two young female soccer players watched video clips of 3 vs. 3 small-sided games and, after occlusion, had to reproduce the positions of the players. Recall performance was measured by calculating the spatial error of the recalled player positions at the moment of occlusion and at consecutive 33ms increments. We analyzed player positions relative to each other, by assessing geometric pattern features in terms of angles between players, and we transformed the data into real-world coordinates to exclude the effects of the 2D perspective in the video clips. The results showed that the participants anticipated the movements of the patterns. In real-world coordinates, the more experienced players anticipated the pattern further in advance than the less experienced players and demonstrated a higher search rate, a shorter fixation duration and a higher fixation order. The differences in recall accuracy between the defensive and offensive elements were not consistent across the methods of analysis and, therefore, we propose that perspective effects of the video clip should be taken into account in further research. Copyright © 2015 Elsevier B.V. All rights reserved.

The movement characteristics of English Premiership rugby union players.

PubMed

Cahill, Nicola; Lamb, Kevin; Worsfold, Paul; Headey, Roy; Murray, Stafford

2013-01-01

The purpose of this investigation was to quantify the movement characteristics of elite rugby union players during competitive play and identify whether position-related differences exist. Ninety-eight elite players from eight English Premiership Clubs were tracked using global positioning systems (GPS) during 44 competitive matches throughout the 2010/2011 season. Player positions were defined as: (1) backs or forwards; (2) front, second and back rows, scrum half, inside and outside backs; (3) 15 individual positions (numbers 1-15). Analysis revealed the game is predominantly played at low speeds with little distance covered 'sprinting' by either the backs (50 ± 76 m) or the forwards (37 ± 64 m). The backs travelled greater (P < 0.05) absolute and relative distances than the forwards. The scrum half covered the greatest total distance during a match (7098 ± 778 m) and the front row the least (5158 ± 200 m). The back row covered the greatest distances at 'sprinting' speeds, particularly the number 8 position (77 m). These findings reflect notable differences in the movement characteristics displayed by elite rugby union players in specific positional roles, and reinforce the contemporary view that training programmes for such players ought to be structured with this in mind.

Designing for movement quality in exergames: lessons learned from observing senior citizens playing stepping games.

PubMed

Skjæret, Nina; Nawaz, Ather; Ystmark, Kristine; Dahl, Yngve; Helbostad, Jorunn L; Svanæs, Dag; Vereijken, Beatrix

2015-01-01

Exergames are increasingly used as an exercise intervention to reduce fall risk in elderly. However, few exergames have been designed specifically for elderly, and we lack knowledge about the characteristics of the movements elicited by exergames and thereby about their potential to train functions important for fall risk reduction. This study investigates game elements and older players' movement characteristics during stepping exergames in order to inform exergame design for movement quality in the context of fall preventive exercise. Fourteen senior citizens (mean age 73 years ± 5.7, range 65 - 85) played 3 stepping exergames in a laboratory. Each of the exergames was described with respect to 7 game elements (physical space, sensing hardware technology, game graphics and sound, model of user, avatar/mapping of movements, game mechanism and game narrative). Five movement characteristics (weight shift; variation in step length, speed, and movement direction; visual independency) were scored on a 5-point Likert scale based on video observations of each player and each game. Disagreement between raters was resolved by agreement. Differences in scores for the 3 exergames were analyzed with a multivariate one-way ANOVA. The Mole received the highest sum score and the best score on each of the 5 movement characteristics (all p values <0.0005). LightRace scored the lowest of the 3 exergames on weight shift and variation in movement direction (both p values <0.0005), while DanceDanceRevolution scored lowest on step length variation and visual independency (p < 0.03 and p < 0.0005, respectively), and lower than The Mole on speed variation (p < 0.05). The physical space players used when exergaming and the on-screen representation of the player, affected movement quality positively as indexed by multiple weight shifts and variation in stepping size, direction, and speed. Furthermore, players' movements improved when playing speed-affected game progression and when the game narrative was related to a natural context. Comparing differences in game elements with associated differences in game movement requirements provides valuable insights about how to design for movement quality in exergames. This provided important lessons for the design of exergames for fall-preventive exercise in senior citizens and illustrates the value of including analyses of movement characteristics when designing such exergames. © 2014 S. Karger AG, Basel.

Development of an Agility Test for Badminton Players and Assessment of Its Validity and Test-Retest Reliability.

PubMed

Loureiro, Luiz de França Bahia; de Freitas, Paulo Barbosa

2016-04-01

Badminton requires open and fast actions toward the shuttlecock, but there is no specific agility test for badminton players with specific movements. To develop an agility test that simultaneously assesses perception and motor capacity and examine the test's concurrent and construct validity and its test-retest reliability. The Badcamp agility test consists of running as fast as possible to 6 targets placed on the corners and middle points of a rectangular area (5.6 × 4.2 m) from the start position located in the center of it, following visual stimuli presented in a luminous panel. The authors recruited 43 badminton players (17-32 y old) to evaluate concurrent (with shuttle-run agility test--SRAT) and construct validity and test-retest reliability. Results revealed that Badcamp presents concurrent and construct validity, as its performance is strongly related to SRAT (ρ = 0.83, P < .001), with performance of experts being better than nonexpert players (P < .01). In addition, Badcamp is reliable, as no difference (P = .07) and a high intraclass correlation (ICC = .93) were found in the performance of the players on 2 different occasions. The findings indicate that Badcamp is an effective, valid, and reliable tool to measure agility, allowing coaches and athletic trainers to evaluate players' athletic condition and training effectiveness and possibly detect talented individuals in this sport.

Coordination pattern of baseball pitching among young pitchers of various ages and velocity levels.

PubMed

Chen, Hsiu-Hui; Liu, Chiang; Yang, Wen-Wen

2016-09-01

This study compared the whole-body movement coordination of pitching among 72 baseball players of various ages and velocity levels. Participants were classified as senior, junior, and little according to their age, with each group comprising 24 players. The velocity levels of the high-velocity (the top eight) and low-velocity (the lowest eight) groups were classified according to their pitching velocity. During pitching, the coordinates of 15 markers attached to the major joints of the whole-body movement system were collected for analysis. Sixteen kinematic parameters were calculated to compare the groups and velocity levels. Principal component analysis (PCA) was conducted to quantify the coordination pattern of pitching movement. The results were as follows: (1) five position and two velocity parameters significantly differed among the age groups, and two position and one velocity parameters significantly differed between the high- and low-velocity groups. (2) The coordination patterns of pitching movement could be described using three components, of which the eigenvalues and contents varied according to age and velocity level. In conclusion, the senior and junior players showed greater elbow angular velocity, whereas the little players exhibited a wider shoulder angle only at the beginning of pitching. The players with high velocity exhibited higher trunk and shoulder rotation velocity. The variations among groups found using PCA and kinematics parameter analyses were consistent.

The Physical and Athletic Performance Characteristics of Division I Collegiate Female Soccer Players by Position.

PubMed

Lockie, Robert G; Moreno, Matthew R; Lazar, Adrina; Orjalo, Ashley J; Giuliano, Dominic V; Risso, Fabrice G; Davis, DeShaun L; Crelling, Jeff B; Lockwood, John R; Jalilvand, Farzad

2018-02-01

Lockie, RG, Moreno, MR, Lazar, A, Orjalo, AJ, Giuliano, DV, Risso, FG, Davis, DL, Crelling, JB, Lockwood, JR, and Jalilvand, F. The physical and athletic performance characteristics of Division I collegiate female soccer players by position. J Strength Cond Res 32(2): 334-343, 2018-Playing positions in soccer can exhibit different movement demands during a match, contributing to variations in physical and performance characteristics. National Collegiate Athletic Association (NCAA) soccer features different substitution rules when compared to FIFA-sanctioned matches, which could influence each players' characteristics. Therefore, this study determined the athletic performance characteristics of Division I female soccer players. Twenty-six players (3 goalkeepers; 8 defenders; 10 midfielders; 5 forwards) from the same squad completed assessments of: lower-body power (vertical and standing broad jump); linear (0-5, 0-10, 0-30 meter [m] sprint intervals) and change-of-direction (pro-agility shuttle; arrowhead change-of-direction speed test) speed; and soccer-specific fitness (Yo-Yo Intermittent Recovery Test [YYIRT] levels 1 and 2). Players were split into position groups, and a Kruskal-Wallis H test with post hoc pairwise analyses (p ≤ 0.05) calculated significant between-group differences. There were no differences in age, height, or body mass between the positions. Midfielders had a faster 0-5 m time compared with the defenders (p = 0.017) and the goalkeepers (p = 0.030). The defenders (p = 0.011) and midfielders (p = 0.013) covered a greater YYIRT2 distance compared with the goalkeepers. There were no other significant between-position differences. Overall, Division I collegiate female players from the same squad demonstrated similar characteristics as measured by soccer-specific performance tests, which could allow for flexibility in position assignments. However, a relatively homogenous squad could also indicate commonality in training prescription, particularly regarding acceleration and high-intensity running. Strength and conditioning coaches may have to consider the specific movement demands of individual positions when training these capacities.

How soccer players head the ball: a test of Optic Acceleration Cancellation theory with virtual reality.

PubMed

McLeod, Peter; Reed, Nick; Gilson, Stuart; Glennerster, Andrew

2008-06-01

We measured the movements of soccer players heading a football in a fully immersive virtual reality environment. In mid-flight the ball's trajectory was altered from its normal quasi-parabolic path to a linear one, producing a jump in the rate of change of the angle of elevation of gaze (alpha) from player to ball. One reaction time later the players adjusted their speed so that the rate of change of alpha increased when it had been reduced and reduced it when it had been increased. Since the result of the player's movement was to regain a value of the rate of change close to that before the disturbance, the data suggest that the players have an expectation of, and memory for, the pattern that the rate of change of alpha will follow during the flight. The results support the general claim that players intercepting balls use servo control strategies and are consistent with the particular claim of Optic Acceleration Cancellation theory that the servo strategy is to allow alpha to increase at a steadily decreasing rate.

The coupling between gaze behavior and opponent kinematics during anticipation of badminton shots.

PubMed

Alder, David; Ford, Paul R; Causer, Joe; Williams, A Mark

2014-10-01

We examined links between the kinematics of an opponent's actions and the visual search behaviors of badminton players responding to those actions. A kinematic analysis of international standard badminton players (n = 4) was undertaken as they completed a range of serves. Video of these players serving was used to create a life-size temporal occlusion test to measure anticipation responses. Expert (n = 8) and novice (n = 8) badminton players anticipated serve location while wearing an eye movement registration system. During the execution phase of the opponent's movement, the kinematic analysis showed between-shot differences in distance traveled and peak acceleration at the shoulder, elbow, wrist and racket. Experts were more accurate at responding to the serves compared to novice players. Expert players fixated on the kinematic locations that were most discriminating between serve types more frequently and for a longer duration compared to novice players. Moreover, players were generally more accurate at responding to serves when they fixated vision upon the discriminating arm and racket kinematics. Findings extend previous literature by providing empirical evidence that expert athletes' visual search behaviors and anticipatory responses are inextricably linked to the opponent action being observed. Copyright © 2014 Elsevier B.V. All rights reserved.

Can Functional Movement Assessment Predict Football Head Impact Biomechanics?

PubMed

Ford, Julia M; Campbell, Kody R; Ford, Cassie B; Boyd, Kenneth E; Padua, Darin A; Mihalik, Jason P

2018-06-01

The purposes of this study was to determine functional movement assessments' ability to predict head impact biomechanics in college football players and to determine whether head impact biomechanics could explain preseason to postseason changes in functional movement performance. Participants (N = 44; mass, 109.0 ± 20.8 kg; age, 20.0 ± 1.3 yr) underwent two preseason and postseason functional movement assessment screenings: 1) Fusionetics Movement Efficiency Test and 2) Landing Error Scoring System (LESS). Fusionetics is scored 0 to 100, and participants were categorized into the following movement quality groups as previously published: good (≥75), moderate (50-75), and poor (<50). The LESS is scored 0 to 17, and participants were categorized into the following previously published movement quality groups: good (≤5 errors), moderate (6-7 errors), and poor (>7 errors). The Head Impact Telemetry (HIT) System measured head impact frequency and magnitude (linear acceleration and rotational acceleration). An encoder with six single-axis accelerometers was inserted between the padding of a commercially available Riddell football helmet. We used random intercepts general linear-mixed models to analyze our data. There were no effects of preseason movement assessment group on the two Head Impact Telemetry System impact outcomes: linear acceleration and rotational acceleration. Head impact frequency did not significantly predict preseason to postseason score changes obtained from the Fusionetics (F1,36 = 0.22, P = 0.643, R = 0.006) or the LESS (F1,36 < 0.01, P = 0.988, R < 0.001) assessments. Previous research has demonstrated an association between concussion and musculoskeletal injury, as well as functional movement assessment performance and musculoskeletal injury. The functional movement assessments chosen may not be sensitive enough to detect neurological and neuromuscular differences within the sample and subtle changes after sustaining head impacts.

Specific Shoulder Pathoanatomy in Semiprofessional Water Polo Players

PubMed Central

Klein, Maria; Tarantino, Ignazio; Warschkow, René; Berger, Claus Joachim; Zdravkovic, Vilijam; Jost, Bernhard; Badulescu, Michael

2014-01-01

Background: Shoulders of throwing and swimming athletes are highly stressed joints that often show structural abnormalities on magnetic resonance imaging (MRI). However, while water polo players exhibit a combination of throwing and swimming movements, a specific pattern of pathological findings has not been described. Purpose: To assess specific MRI abnormalities in shoulders of elite water polo players and to compare these findings with a healthy control group. Study Design: Cross-sectional study; Level of evidence, 3. Methods: After performing a power analysis, volunteers were recruited for this study. Both shoulders of 28 semiprofessional water polo players and 15 healthy volunteers were assessed clinically (based on the Constant score) and had bilateral shoulder MRIs. The shoulders were clustered into 3 groups: 28 throwing and 28 nonthrowing shoulders of water polo athletes and 30 shoulders of healthy control subjects. Results: Twenty-eight male water polo players with an average age of 24 years and 15 healthy subjects (30 shoulders) with an average age of 31 years were examined. Compared with controls, significantly more MRI abnormalities in the water polo players' throwing shoulders could be found in the subscapularis, infraspinatus, and posterior labrum (P = .001, P = .024, and P = .041, respectively). Other structures showed no statistical differences between the 3 groups, including the supraspinatus tendon, which had abnormalities in 36% of throwing versus 32% of nonthrowing shoulders and 33% of control shoulders. All throwing shoulders showed abnormal findings in the MRI, but only 8 (29%) were symptomatic. Conclusion: The shoulders of semiprofessional water polo players demonstrated abnormalities in subscapularis and infraspinatus tendons that were not typical abnormalities for swimmers or throwing athletes. Clinical Relevance: The throwing shoulders of water polo players have specific MRI changes. Clinical symptoms do not correlate with the MRI findings. PMID:26535326

Morphological and motor characteristics of Croatian first league female football players.

PubMed

Jelaska, Petra Mandić; Katić, Ratko; Jelaska, Igor

2013-05-01

The aim of this study was to determine the structure of morphological and motor characteristics of Croatian first league female football players and their impact on the estimated quality of the players. According to the goal of the research, a sample consisted of 70 Croatian first league female football players. Participants were measured in 18 tests for assessing morphological characteristics, a set of 12 basic motor abilities tests and a set of 7 tests for assessing football-specific motor abilities. Exploratory factor analysis strategy was applied separately to all measured tests: morphological, basic motor abilities and football specific motor abilities. Factor analysis of morphological tests has shown existence of 3 significant latent dimensions that explain 64% of the total variability. Factors are defined as transverse dimensionality of the skeleton and voluminosity (35%), subcutaneous fat tissue (16%) and longitudinal dimensionality of the skeleton (13%). In the area of basic motor abilities, four factors were extracted. The first factor is responsible for the integration of agility and explosive power of legs, i.e. a factor of movement regulation (agility/lower body explosiveness) (23%), the second one defines muscle tone regulation (15%), the third one defines the frequency of leg movements (12%), while the fourth one is recognized as responsible for the manifestation of basic strength, particularly of basic core strength (19%). Two factors were isolated in the space of football-specific motor abilities: football-specific efficiency (53%) and situational football coordination (27%). Furthermore, by use of factor analysis on extracted latent dimensions (morphological, basic and football specific motor abilities) two higher order factors (explaining 87% of common variability) were extracted. They were named morphological-motor factor (54%) and football-specific motor abilities factor (33%). It is assumed that two extracted higher-order factors fully describe morphological and motor status of first league female football players. Furthermore, the linear regression results in latent space showed that the identified factors are very good predictors of female football players quality (delta = 0.959). In doing so, both specific motor abilities factors and the first factor of basic motor abilities as a factor of general motor efficiency have the greatest impact on player quality, and these factors have been identified as most important predictors of player quality in Croatian women's first league and elite female football players in general. Obtained results provide deep insight into the structure of relations between the morphological, motor and specific motor variables and also indicate the importance of such definition of specific motor abilities. Consequently, results explicitly indicate the necessity of early, continuous, and systematic development of football-specific motor abilities in female football players of high competitive level but also, adjusted, to the younger age categories.

Previously identified patellar tendinopathy risk factors differ between elite and sub-elite volleyball players.

PubMed

Janssen, I; Steele, J R; Munro, B J; Brown, N A T

2015-06-01

Patellar tendinopathy is the most common knee injury incurred in volleyball, with its prevalence in elite athletes more than three times that of their sub-elite counterparts. The purpose of this study was to determine whether patellar tendinopathy risk factors differed between elite and sub-elite male volleyball players. Nine elite and nine sub-elite male volleyball players performed a lateral stop-jump block movement. Maximum vertical jump, training history, muscle extensibility and strength, three-dimensional landing kinematics (250 Hz), along with lower limb neuromuscular activation patterns (1500 Hz), and patellar tendon loading were collected during each trial. Multivariate analyses of variance (P < 0.05) assessed for between-group differences in risk factors or patellar tendon loading. Significant interaction effects were further evaluated using post-hoc univariate analysis of variance tests. Landing kinematics, neuromuscular activation patterns, patellar tendon loading, and most of the previously identified risk factors did not differ between the elite and sub-elite players. However, elite players participated in a higher training volume and had less quadriceps extensibility than sub-elite players. Therefore, high training volume is likely the primary contributor to the injury discrepancy between elite and sub-elite volleyball players. Interventions designed to reduce landing frequency and improve quadriceps extensibility are recommended to reduce patellar tendinopathy prevalence in volleyball players. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Improving the 'how' and 'what' decisions of elite table tennis players.

PubMed

Raab, Markus; Masters, Rich S W; Maxwell, Jonathan P

2005-06-01

Training methods in sport usually focus on improving either technical or tactical aspects of performance, ignoring the fact that successful performance requires the athlete to simultaneously decide what movement to perform and how it should be executed. Young elite table tennis players were trained, in a first phase, to improve their forehand and backhand movements and, in a second phase, to make a tactical switch between forehand and backhand movements. Half of the players took part in behavioral training focusing on how to perform the required movements, whereas half received additional video feedback about their technical and tactical performance (decision training). The results indicate that improvements of how decisions (techniques) and what decisions (tactics) can occur as a consequence of combining technical and tactical training. These results were stable in delayed Post-test analyses of competitive matches. It was concluded that a combination of both technical and tactical training is beneficial to elite table tennis performers, particularly during early seasonal training programs.

Wearable nanosensor system for monitoring mild traumatic brain injuries in football players

NASA Astrophysics Data System (ADS)

Ramasamy, Mouli; Varadan, Vijay K.

2016-04-01

Football players are more to violent impacts and injuries more than any athlete in any other sport. Concussion or mild traumatic brain injuries were one of the lesser known sports injuries until the last decade. With the advent of modern technologies in medical and engineering disciplines, people are now more aware of concussion detection and prevention. These concussions are often overlooked by football players themselves. The cumulative effect of these mild traumatic brain injuries can cause long-term residual brain dysfunctions. The principle of concussion is based the movement of the brain in the neurocranium and viscerocranium. The brain is encapsulated by the cerebrospinal fluid which acts as a protective layer for the brain. This fluid can protect the brain against minor movements, however, any rapid movements of the brain may mitigate the protective capability of the cerebrospinal fluid. In this paper, we propose a wireless health monitoring helmet that addresses the concerns of the current monitoring methods - it is non-invasive for a football player as helmet is not an additional gear, it is efficient in performance as it is equipped with EEG nanosensors and 3D accelerometer, it does not restrict the movement of the user as it wirelessly communicates to the remote monitoring station, requirement of individual monitoring stations are not required for each player as the ZigBee protocol can couple multiple transmitters with one receiver. A helmet was developed and validated according to the above mentioned parameters.

Wireless nanosensors for monitoring concussion of football players

NASA Astrophysics Data System (ADS)

Ramasamy, Mouli; Harbaugh, Robert E.; Varadan, Vijay K.

2015-04-01

Football players are more to violent impacts and injuries more than any athlete in any other sport. Concussion or mild traumatic brain injuries were one of the lesser known sports injuries until the last decade. With the advent of modern technologies in medical and engineering disciplines, people are now more aware of concussion detection and prevention. These concussions are often overlooked by football players themselves. The cumulative effect of these mild traumatic brain injuries can cause long-term residual brain dysfunctions. The principle of concussion is based the movement of the brain in the neurocranium and viscerocranium. The brain is encapsulated by the cerebrospinal fluid which acts as a protective layer for the brain. This fluid can protect the brain against minor movements, however, any rapid movements of the brain may mitigate the protective capability of the cerebrospinal fluid. In this paper, we propose a wireless health monitoring helmet that addresses the concerns of the current monitoring methods - it is non-invasive for a football player as helmet is not an additional gear, it is efficient in performance as it is equipped with EEG nanosensors and 3D accelerometer, it does not restrict the movement of the user as it wirelessly communicates to the remote monitoring station, requirement of individual monitoring stations are not required for each player as the ZigBee protocol can couple multiple transmitters with one receiver. A helmet was developed and validated according to the above mentioned parameters.

Kinetic and Kinematic Analysis for Assessing the Differences in Countermovement Jump Performance in Rugby Players.

PubMed

Floría, Pablo; Gómez-Landero, Luis A; Suárez-Arrones, Luis; Harrison, Andrew J

2016-09-01

Floría, P, Gómez-Landero, LA, Suárez-Arrones, L, and Harrison, AJ. Kinetic and kinematic analysis for assessing the differences in countermovement jump performance in rugby players. J Strength Cond Res 30(9): 2533-2539, 2016-The aim of this study was to ascertain the differences in kinetic and kinematic profiles between better and poorer performers of the vertical jump within a homogeneous group of trained adults. Fifty rugby players were divided into low scoring (LOW) and high scoring (HIGH) groups based on their performance in the vertical jump. The force, velocity, displacement, and rate of force development (RFD)-time curves were analyzed to determine the differences between groups. The analysis of the data showed differences in all the patterns of the ensemble mean curves of the HIGH and LOW groups. During the eccentric phase, the differences in the HIGH group with respect to the LOW group were lower crouch position, higher downward velocity, and higher force and RFD during the braking of the downward movement. During the concentric phase, the HIGH group achieved higher upward velocity, higher force at the end of phase, and a higher position at takeoff. The higher jump performances seem to be related to a more effective stretch-shortening cycle function that is characterized by a deeper and faster countermovement with higher eccentric forces being applied to decelerate the downward movement leading to enhanced force generation during the concentric phase.

Effects of Strength Training Combined with Specific Plyometric exercises on body composition, vertical jump height and lower limb strength development in elite male handball players: a case study.

PubMed

Carvalho, Alberto; Mourão, Paulo; Abade, Eduardo

2014-06-28

The purpose of the present study was to identify the effects of a strength training program combined with specific plyometric exercises on body composition, vertical jump (VJ) height and strength development of lower limbs in elite male handball players. A 12-week program with combined strength and specific plyometric exercises was carried out for 7 weeks. Twelve elite male handball players (age: 21.6 ± 1.73) competing in the Portuguese Major League participated in the study. Besides the anthropometric measurements, several standardized jump tests were applied to assess VJ performance together with the strength development of the lower limbs in an isokinetic setting. No significant changes were found in body circumferences and diameters. Body fat content and fat mass decreased by 16.4 and 15.7% respectively, while lean body mass increased by 2.1%. Despite small significance, there was in fact an increase in squat jump (SJ), counter movement jump (CMJ) and 40 consecutive jumps after the training period (6.1, 3.8 and 6.8%, respectively). After the applied protocol, peak torque increased in lower limb extension and flexion in the majority of the movements assessed at 90ºs-1. Consequently, it is possible to conclude that combining general strength-training with plyometric exercises can not only increase lower limb strength and improve VJ performance but also reduce body fat content.

Effects of Strength Training Combined with Specific Plyometric exercises on body composition, vertical jump height and lower limb strength development in elite male handball players: a case study

PubMed Central

Carvalho, Alberto; Mourão, Paulo; Abade, Eduardo

2014-01-01

The purpose of the present study was to identify the effects of a strength training program combined with specific plyometric exercises on body composition, vertical jump (VJ) height and strength development of lower limbs in elite male handball players. A 12-week program with combined strength and specific plyometric exercises was carried out for 7 weeks. Twelve elite male handball players (age: 21.6 ± 1.73) competing in the Portuguese Major League participated in the study. Besides the anthropometric measurements, several standardized jump tests were applied to assess VJ performance together with the strength development of the lower limbs in an isokinetic setting. No significant changes were found in body circumferences and diameters. Body fat content and fat mass decreased by 16.4 and 15.7% respectively, while lean body mass increased by 2.1%. Despite small significance, there was in fact an increase in squat jump (SJ), counter movement jump (CMJ) and 40 consecutive jumps after the training period (6.1, 3.8 and 6.8%, respectively). After the applied protocol, peak torque increased in lower limb extension and flexion in the majority of the movements assessed at 90ºs-1. Consequently, it is possible to conclude that combining general strength-training with plyometric exercises can not only increase lower limb strength and improve VJ performance but also reduce body fat content. PMID:25114739

Initial Movement and Continuity in Vibrato among High School and University String Players

ERIC Educational Resources Information Center

Geringer, John M.; Allen, Michael L.; MacLeod, Rebecca B.

2005-01-01

The purpose of the present study was to investigate aspects of vibrato performance among high school and university string players. The main questions were to determine whether students consistently initiate vibrato in an upward or downward direction and whether players vibrate continuously when performing slurs. Forty high school and university…

How soccer players head the ball: A test of optic acceleration cancellation theory with virtual reality

PubMed Central

McLeod, Peter; Reed, Nick; Gilson, Stuart; Glennerster, Andrew

2010-01-01

We measured the movements of soccer players heading a football in a fully immersive virtual reality environment. In mid-flight the ball’s trajectory was altered from its normal quasi-parabolic path to a linear one, producing a jump in the rate of change of the angle of elevation of gaze (α) from player to ball. One reation time later the players adjusted their speed so that the rate of change of α increased when it had been reduced and reduced it when it had been increased. Since the result of the player’s movement was to regain a value of the rate of change close to that before the disturbance, the data suggest that the players have an expectation of, and memory for, the pattern that the rate of change of α will follow during the flight. The results support the general claim that players intercepting balls use servo control strategies and are consistent with the particular claim of Optic Acceleration Cancellation theory that the servo strategy is to allow α to increase at a steadily decreasing rate. PMID:18472123

Using budget-friendly methods to analyze sport specific movements

NASA Astrophysics Data System (ADS)

Jackson, Lindsay; Williams, Sarah; Ferrara, Davon

2015-03-01

When breaking down the physics behind sport specific movements, athletes, usually professional, are often assessed in multimillion-dollar laboratories and facilities. Budget-friendly methods, such as video analysis using low-cost cameras, iPhone sensors, or inexpensive force sensors can make this process more accessible to amateur athletes, which in-turn can give insight into injury mechanisms. Here we present a comparison of two methods of determining the forces experienced by a cheerleader during co-education stunting and soccer goalies while side-diving. For the cheerleader, accelerometer measurements were taken by an iPhone 5 and compared to video analysis. The measurements done on the soccer players were taken using FlexiForce force sensors and again compared to video analysis. While these budget-friendly methods could use some refining, they show promise for producing usable measurements for possibly increasing our understanding of injury in amateur players. Furthermore, low-cost physics experiments with sports can foster an active learning environment for students with minimum physics and mathematical background.

CONSISTENCY OF FIELD-BASED MEASURES OF NEUROMUSCULAR CONTROL USING FORCE PLATE DIAGNOSTICS IN ELITE MALE YOUTH SOCCER PLAYERS

PubMed Central

READ, PAUL; OLIVER, JON L.; DE STE CROIX, MARK B.A.; MYER, GREGORY D.; LLOYD, RHODRI S.

2016-01-01

Deficits in neuromuscular control during movement patterns such as landing are suggested pathomechanics that underlie sport-related injury. A common mode of assessment is measurement of landing forces during jumping tasks; however, these measures have been used less frequently in male youth soccer players and reliability data is sparse. The aim of this study was to examine the reliability of a field-based neuromuscular control screening battery using force plate diagnostics in this cohort. Twenty six pre-peak height velocity (PHV) and twenty five post-PHV elite male youth soccer players completed a drop vertical jump (DVJ), single leg 75% horizontal hop and stick (75%HOP) and single leg countermovement jump (SLCMJ). Measures of peak landing vertical ground reaction force (pVGRF), time to stabilisation (TTS), time to pVGRF, and pVGRF asymmetry were recorded. A test, re-test design was used and reliability statistics included: change in mean, intraclass correlation coefficient (ICC) and coefficient of variation (CV). No significant differences in mean score were reported for any of the assessed variables between test sessions. In both groups, pVGRF and asymmetry during the 75%HOP and SLCMJ demonstrated largely acceptable reliability (CV ≤ 10%). Greater variability was evident in DVJ pVGRF and all other assessed variables, across the three protocols (CV range = 13.8 – 49.7%). ICC values ranged from small to large and were generally higher in the post-PHV players. The results of this study suggest that pVGRF and asymmetry can be reliably assessed using a 75%HOP and SLCMJ in this cohort. These measures could be utilized to support a screening battery for elite male youth soccer players and for test re-test comparison. PMID:27075641

The association of visually-assessed quality of movement during jump-landing with ankle dorsiflexion range-of-motion and hip abductor muscle strength among healthy female athletes.

PubMed

Rabin, Alon; Einstein, Ofira; Kozol, Zvi

2018-05-01

To explore the association between ankle dorsiflexion (DF) range of motion (ROM), and hip abductor muscle strength, to visually-assessed quality of movement during jump-landing. Cross-sectional. Gymnasium of participating teams. 37 female volleyball players. Quality of movement in the frontal-plane, sagittal-plane, and overall (both planes) was visually rated as "good/moderate" or "poor". Weight-bearing Ankle DF ROM and hip abductor muscle strength were compared between participants with differing quality of movement. Weight-bearing DF ROM on both sides was decreased among participants with "poor" sagittal-plane quality of movement (dominant side: 50.8° versus 43.6°, P = .02; non-dominant side: 54.6° versus 45.9°, P = .01), as well as among participants with an overall "poor" quality of movement (dominant side: 51.8° versus 44.0°, P < .01; non-dominant side: 56.5° versus 45.1°, P < .01). Weight-bearing ankle DF on the non-dominant side was decreased among participants with a "poor" frontal-plane quality of movement (53.9° versus 46.0°, P = .02). No differences in hip abductor muscle strength were noted between participants with differing quality of movement. Visual assessment of jump-landing can detect differences in quality of movement that are associated with ankle DF ROM. Clinicians observing a poor quality of movement may wish to assess ankle DF ROM. Copyright © 2018 Elsevier Ltd. All rights reserved.

Strength and Power Correlates of Throwing Velocity on Subelite Male Cricket Players.

PubMed

Freeston, Jonathan L; Carter, Thomas; Whitaker, Gary; Nicholls, Owen; Rooney, Kieron B

2016-06-01

Throwing velocity is an important aspect of fielding in cricket to affect run-outs and reduce the opponent's run-scoring opportunities. Although a relationship between strength and/or power and throwing velocity has been well established in baseball, water polo, and European handball, it has not been adequately explored in cricket. Consequently, this study aimed to determine the relationship between measures of strength and/or power and throwing velocity in cricket players. Seventeen male cricket players (mean ± SD; age, 21.1 ± 1.6 years; height, 1.79 ± 0.06 m; weight, 79.8 ± 6.4 kg) from an elite athlete program were tested for maximal throwing velocity from the stretch position and after a 3-meter shuffle. They were also assessed for strength and power using a range of different measures. Throwing velocity from the stretch position (30.5 ± 2.4 m·s) was significantly related to dominant leg lateral-to-medial jump (LMJ) distance (r = 0.71; p < 0.01), dominant shoulder internal rotation (IR) strength (r = 0.55; p ≤ 0.05), and dominant (r = 0.73; p < 0.01) and nondominant (r = 0.54; p ≤ 0.05) medicine ball rotation (MB Rot) throw velocity and medicine ball chest pass (MB CP) distance (r = 0.67; p < 0.01). A nonsignificant trend was observed for vertical jump (VJ) height (p = 0.06), whereas no significant relationships were observed for nondominant LMJ distance (p = 0.97), nondominant shoulder IR strength (p = 0.80), 1 repetition maximum (RM) squat strength (p = 0.57), 1RM bench press strength (p = 0.90), height (p = 0.33), or weight (p = 0.29). Multiple regression analysis revealed that dominant MB Rot and MB CP explained 66% of the variance. The results were similar for velocity after a shuffle step (31.8 ± 2.1 m·s); however, VJ height reached statistical significance (r = 0.51; p ≤ 0.05). The multiple regression was also similar with MB Rot and MB CP explaining 70% of the variance. The cricketers in this study threw with greater velocity than elite junior and subelite senior cricketers but with lower velocities than elite senior cricketers and collegiate level and professional baseball players. This is the first study to demonstrate a link between strength and/or power and throwing velocity in cricket players and highlight the importance of power development as it relates to throwing velocity. Exercises that more closely simulated the speed (body weight jumps and medicine ball throws) or movement pattern (shoulder IR) of overhead throwing were greater predictors of throwing velocity. Strength and conditioning staff should assess and develop power to enhance throwing performance in cricket players. Exercises with greater movement and speed specificity to throwing should be used in preference over exercises that are slower and have less movement specificity to the throwing motion. Cricket players should engage in power training to bridge the gap in performance between them and baseball players.

Effects of Different Post-Activation Potentiation Warm-Ups on Repeated Sprint Ability in Soccer Players from Different Competitive Levels.

PubMed

Sanchez-Sanchez, Javier; Rodriguez, Alejandro; Petisco, Cristina; Ramirez-Campillo, Rodrigo; Martínez, Cristian; Nakamura, Fábio Y

2018-03-01

This study aimed to compare the effects of a traditional warm-up with two post-activation potentiation (PAP) warm-up strategies on the repeated sprint ability (RSA) of soccer players from national (NL) and regional (RL) competitive levels. Sixteen young players (NL, n = 8, age = 20.7 ± 1.4 y, body mass = 68.5 ± 7.0 kg, body height = 177.4 ± 5.2 cm; RL, n = 8, age = 20.8 ± 1.0 y, body mass = 68.7 ± 4.0 kg, body height = 176.6 ± 5.6 cm) were recruited to complete a traditional warm-up (CONTROL), a PAP warm-up incorporating squats with a load (~60% 1RM) that allowed a high speed (1 m/s) of movement and a high number of repetitions (PAP-1), and a PAP warm-up with a load (~90% 1RM) that allowed a moderate speed (0.5 m/s) of movement and a reduced number of repetitions (PAP-0.5). A RSA test (six 20-m sprints with 20 s of recovery) was performed 5 min after the PAP warm-up to assess the effects of the different protocols on the fastest sprint (RSAb) and the mean time of all sprints (RSAm). A meaningful improvement of RSA performance was observed with PAP-0.5, attaining a large effect on NL (RSAb, ES = -1.5; RSAm, ES = -1.3) and only a small effect on RL athletes (RSAb and RSAm, ES = -0.2). Moreover, when each RSA sprint performance was compared between NL and RL players, after PAP-0.5 greater performance for all sprints was observed in the NL players. Therefore, adding a heavy strength-based conditioning exercise during the warm-up prior to a RSA test may induce significant performance improvements in NL, but only small effects in RL players.

Effects of Different Post-Activation Potentiation Warm-Ups on Repeated Sprint Ability in Soccer Players from Different Competitive Levels

PubMed Central

Sanchez-Sanchez, Javier; Rodriguez, Alejandro; Petisco, Cristina; Ramirez-Campillo, Rodrigo; Martínez, Cristian; Nakamura, Fábio Y.

2018-01-01

Abstract This study aimed to compare the effects of a traditional warm-up with two post-activation potentiation (PAP) warm-up strategies on the repeated sprint ability (RSA) of soccer players from national (NL) and regional (RL) competitive levels. Sixteen young players (NL, n = 8, age = 20.7 ± 1.4 y, body mass = 68.5 ± 7.0 kg, body height = 177.4 ± 5.2 cm; RL, n = 8, age = 20.8 ± 1.0 y, body mass = 68.7 ± 4.0 kg, body height = 176.6 ± 5.6 cm) were recruited to complete a traditional warm-up (CONTROL), a PAP warm-up incorporating squats with a load (~60% 1RM) that allowed a high speed (1 m/s) of movement and a high number of repetitions (PAP-1), and a PAP warm-up with a load (~90% 1RM) that allowed a moderate speed (0.5 m/s) of movement and a reduced number of repetitions (PAP-0.5). A RSA test (six 20-m sprints with 20 s of recovery) was performed 5 min after the PAP warm-up to assess the effects of the different protocols on the fastest sprint (RSAb) and the mean time of all sprints (RSAm). A meaningful improvement of RSA performance was observed with PAP-0.5, attaining a large effect on NL (RSAb, ES = -1.5; RSAm, ES = -1.3) and only a small effect on RL athletes (RSAb and RSAm, ES = -0.2). Moreover, when each RSA sprint performance was compared between NL and RL players, after PAP-0.5 greater performance for all sprints was observed in the NL players. Therefore, adding a heavy strength-based conditioning exercise during the warm-up prior to a RSA test may induce significant performance improvements in NL, but only small effects in RL players. PMID:29599871

Consistency of Field-Based Measures of Neuromuscular Control Using Force-Plate Diagnostics in Elite Male Youth Soccer Players.

PubMed

Read, Paul J; Oliver, Jon L; Croix, Mark Ba De Ste; Myer, Gregory D; Lloyd, Rhodri S

2016-12-01

Read, P, Oliver, JL, Croix, MD, Myer, GD, and Lloyd, RS. Consistency of field-based measures of neuromuscular control using force-plate diagnostics in elite male youth soccer players. J Strength Cond Res 30(12): 3304-3311, 2016-Deficits in neuromuscular control during movement patterns such as landing are suggested pathomechanics that underlie sport-related injury. A common mode of assessment is measurement of landing forces during jumping tasks; however, these measures have been used less frequently in male youth soccer players, and reliability data are sparse. The aim of this study was to examine the reliability of a field-based neuromuscular control screening battery using force-plate diagnostics in this cohort. Twenty-six pre-peak height velocity (PHV) and 25 post-PHV elite male youth soccer players completed a drop vertical jump (DVJ), single-leg 75% horizontal hop and stick (75%HOP), and single-leg countermovement jump (SLCMJ). Measures of peak landing vertical ground reaction force (pVGRF), time to stabilization, time to pVGRF, and pVGRF asymmetry were recorded. A test-retest design was used, and reliability statistics included change in mean, intraclass correlation coefficient, and coefficient of variation (CV). No significant differences in mean score were reported for any of the assessed variables between test sessions. In both groups, pVGRF and asymmetry during the 75%HOP and SLCMJ demonstrated largely acceptable reliability (CV ≤ 10%). Greater variability was evident in DVJ pVGRF and all other assessed variables, across the 3 protocols (CV range = 13.8-49.7%). Intraclass correlation coefficient values ranged from small to large and were generally higher in the post-PHV players. The results of this study suggest that pVGRF and asymmetry can be reliably assessed using a 75%HOP and SLCMJ in this cohort. These measures could be used to support a screening battery for elite male youth soccer players and for test-retest comparison.

Fundamentals of Embouchure in Brass Players: Towards a Definition and Clinical Assessment.

PubMed

Woldendorp, Kees H; Boschma, Hans; Boonstra, Anne M; Arendzen, Hans J; Reneman, Michiel F

2016-12-01

Brass players may experience problems producing an optimal sound (or range of sounds) in their instrument. Assessing and treating dysfunctional embouchure requires knowledge of functional embouchure, but peer-reviewed literature on dysfunctional and functional embouchure is scarce. This study aimed to provide a narrative overview of embouchure based on information from different scientific and clinical fields. This should be regarded as a first step in constructing a reliable, valid, and practical multi-item method to assess embouchure for brass players. Literature reviews were conducted concerning: 1) the definition of embouchure, 2) physics and acoustics of embouchure, 3) functioning of embouchure-related structures, and 4) instruments to assess embouchure. Also, embouchure experts (clinicians, scientists, and elite wind players) were consulted for information and discussion. A proposal for a new definition of embouchure, an overview of the relevant physics and acoustics, functions of embouchure-related body structures, and the main methods to measure embouchure in brass playing are presented. Peer-reviewed information about the fundamentals of dysfunctional embouchure is scarce and sometimes contradictory. A new definition for embouchure is proposed: embouchure is the process needed to adjust the amount, pressure, and direction of the air flow (generated by the breath support) as it travels through the mouth cavity and between the lips, by the position and/or movements of the tongue, teeth, jaws, cheeks, and lips, to produce a tone in a wind instrument. An integrative overview is presented which can serve as a transparent foundation for the present understanding of functional and dysfunctional embouchure and for developing an evidence-based multi-item assessment instrument.

Habituation of 10-year-old hockey players to treadmill skating.

PubMed

Lockwood, Kelly L; Frost, Gail

2007-05-01

This study assessed changes in selected physiological and kinematic variables over 6 weeks of treadmill skating in an effort to understand the process of habituation to this novel training modality. Seven male, Atom-A hockey players who were injury-free and had no previous treadmill skating experience participated in the study. Players performed four 1-min skating bouts at progressively increasing speeds, each week, for 6 weeks. One speed (10.5 km/h) was repeated weekly to allow for assessment of the habituation process. Our criteria for habituation were: a decrease in stride rate, heart rate and rating of perceived exertion, and an increase in stride length, trunk angle and vertical movement of the centre of mass, leading to a plateau, over the course of the 6-week study. Significant decreases were seen in stride rate, heart rate and ratings of perceived exertion, and significant increases were found in stride length. Some of these changes were evident after only one week of training and all were present by week 4. After 6 weeks (24 min) of exposure to treadmill skating, all participants displayed a visibly more efficient skating style.

The effect of an early dismissal on player work-rate in a professional soccer match.

PubMed

Carling, Christopher; Bloomfield, Jonathan

2010-01-01

The aim of this study was to examine the effects of an early dismissal (after 5-min play) on work-rate in a professional soccer match. A computerised player tracking system was used to assess the work-rates of seven players who completed the match on a team with 10 players. A minute-by-minute analysis of the remaining 91min following the dismissal was performed for the total distance covered, the distance covered in five categories of movement intensity and the recovery time between high-intensity efforts for each player. The data were calculated for each half and for three equal intervals within each half and profiled against normative data for the same players obtained from the analysis of 15 games in the same season. Following the dismissal, the players covered a greater total distance than normal (p<0.025), particularly in moderate-intensity activities (p<0.01) and had shorter recovery times between high-intensity efforts (p<0.025). In contrast, there was a significant reduction between game halves for total distance covered at both the highest (p<0.025) and lowest running intensities (p<0.01). However, there were no differences in high-intensity activities across the three intervals in the second-half. These findings suggest that in 11 vs. 11, players may not always utilise their full physical potential as this match illustrated an increase in overall work-rate when reduced to 10 players. However, as a team with 10 players is likely to incur higher levels of fatigue, tactical alterations may be necessary and/or players may adopt a pacing strategy to endure the remainder of the match. Copyright (c) 2008 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Fluid and Electrolyte Needs for Training, Competition, and Recovery

DTIC Science & Technology

2011-01-01

begin both training and competition in a state of fluid deficit. Analysis of samples collected from elite football ( soccer ) players before training...surprisingly, samples collected from players before a competitive game revealed that 8 of the 20 outfield players had a urine osmolality in excess of...2007) reported that basketball players attempted fewer shots and were less able to make shots linked with movement (e.g. lay-up) when dehydration had

Effectiveness of a tailored neck training program on neck strength, movement, and fatigue in under-19 male rugby players: a randomized controlled pilot study.

PubMed

Barrett, Matthew D; McLoughlin, Terence F; Gallagher, Kieran R; Gatherer, Don; Parratt, Michael Tr; Perera, Jonathan R; Briggs, Tim Wr

2015-01-01

To investigate the effect of a tailored neck muscle conditioning program on neck muscle strength, neck muscle fatigue, and range of neck movement in 16-18-year-old male rugby players. Thirty-four male rugby players were divided into forward and back playing positions and randomized within these groups. Seventeen players were randomly assigned to each group. The test group was given a tailored 6-week exercise regime based on their baseline measurements to be performed three times a week in addition to their normal training and playing. The control group trained and played as normal. The outcome measures used were cervical spine range of movement, neck strength, and neck muscle fatigability. There were no clinically relevant statistically significant differences between the two groups. Trends identified between the two groups suggest that a tailored neck exercise program increases neck strength, particularly neck extension, and increases resistance to fatigue, as well as influencing right- and left-sided neck muscle balance. A reduction in range of movement was also demonstrated in the test group. There was a great deal of variability in range of movement and strength within this age group. No previously undiagnosed neck conditions were detected, and there were no adverse events reported. This study has shown that neck strength, range of movement, and susceptibility of the neck muscles to fatigue can be influenced using a focused neck training regime. It forms an important basis for a larger, multicenter study to ensure the neck is given due attention in rugby training and receives the same focus of conditioning as other parts of the body.

Detecting Deception in Movement: The Case of the Side-Step in Rugby

PubMed Central

Brault, Sébastien; Bideau, Benoit; Kulpa, Richard; Craig, Cathy M.

2012-01-01

Although coordinated patterns of body movement can be used to communicate action intention, they can also be used to deceive. Often known as deceptive movements, these unpredictable patterns of body movement can give a competitive advantage to an attacker when trying to outwit a defender. In this particular study, we immersed novice and expert rugby players in an interactive virtual rugby environment to understand how the dynamics of deceptive body movement influence a defending player’s decisions about how and when to act. When asked to judge final running direction, expert players who were found to tune into prospective tau-based information specified in the dynamics of ‘honest’ movement signals (Centre of Mass), performed significantly better than novices who tuned into the dynamics of ‘deceptive’ movement signals (upper trunk yaw and out-foot placement) (p<.001). These findings were further corroborated in a second experiment where players were able to move as if to intercept or ‘tackle’ the virtual attacker. An analysis of action responses showed that experts waited significantly longer before initiating movement (p<.001). By waiting longer and picking up more information that would inform about future running direction these experts made significantly fewer errors (p<.05). In this paper we not only present a mathematical model that describes how deception in body-based movement is detected, but we also show how perceptual expertise is manifested in action expertise. We conclude that being able to tune into the ‘honest’ information specifying true running action intention gives a strong competitive advantage. PMID:22701569

Analysis of male volleyball players' motor activities during a top level match.

PubMed

Mroczek, Dariusz; Januszkiewicz, Aleksander; Kawczyński, Adam S; Borysiuk, Zbigniew; Chmura, Jan

2014-08-01

The present study aims to assess motor activity of volleyball players using an original video recording method developed by the authors. Twenty-eight volleyball players taking part in 4 matches of the Polish Volleyball League were examined. The recorded data were analyzed in view of the mean total distance covered by volleyball players on different court positions during a match, set, and rally. The results showed that volleyball players cover the mean total distance of 1221 ± 327 m (mean ± SD) in a 3-set match, and 1757 ± 462 m in a 4-set match. A statistically significant difference (p ≤ 0.005) was found between the distance covered by the middle blockers and setters, defenders, spikers, and libero players in a match and in a set. The study revealed a tendency to lengthen the distance by the players in the final sets, which is indicative of the extended time of individual rallies. The mean distance covered in a single rally amounted to 10.92 ± 0.9 m in 4 matches (between 9.12 and 12.56 m). Considering the limited size of the field of play, volleyball players cover relatively long distances during a match and individual sets, with the shortest distance covered by middle blockers, and the longest by setters. From a practical application point of view, detailed topographic analysis of a player's movements on the court as well as precise data on the time of activity and rest breaks provide the coach with valuable information on the ways of development of arrhythmic, changing and dynamic training loads.

The key to success in elite athletes? Explicit and implicit motor learning in youth elite and non-elite soccer players.

PubMed

Verburgh, L; Scherder, E J A; van Lange, P A M; Oosterlaan, J

2016-09-01

In sports, fast and accurate execution of movements is required. It has been shown that implicitly learned movements might be less vulnerable than explicitly learned movements to stressful and fast changing circumstances that exist at the elite sports level. The present study provides insight in explicit and implicit motor learning in youth soccer players with different expertise levels. Twenty-seven youth elite soccer players and 25 non-elite soccer players (aged 10-12) performed a serial reaction time task (SRTT). In the SRTT, one of the sequences must be learned explicitly, the other was implicitly learned. No main effect of group was found for implicit and explicit learning on mean reaction time (MRT) and accuracy. However, for MRT, an interaction was found between learning condition, learning phase and group. Analyses showed no group effects for the explicit learning condition, but youth elite soccer players showed better learning in the implicit learning condition. In particular, during implicit motor learning youth elite soccer showed faster MRTs in the early learning phase and earlier reached asymptote performance in terms of MRT. Present findings may be important for sports because children with superior implicit learning abilities in early learning phases may be able to learn more (durable) motor skills in a shorter time period as compared to other children.

Eccentric-Overload Training in Team-Sport Functional Performance: Constant Bilateral Vertical Versus Variable Unilateral Multidirectional Movements.

PubMed

Gonzalo-Skok, Oliver; Tous-Fajardo, Julio; Valero-Campo, Carlos; Berzosa, César; Bataller, Ana Vanessa; Arjol-Serrano, José Luis; Moras, Gerard; Mendez-Villanueva, Alberto

2017-08-01

To analyze the effects of 2 different eccentric-overload training (EOT) programs, using a rotational conical pulley, on functional performance in team-sport players. A traditional movement paradigm (ie, squat) including several sets of 1 bilateral and vertical movement was compared with a novel paradigm including a different exercise in each set of unilateral and multi-directional movements. Forty-eight amateur or semiprofessional team-sport players were randomly assigned to an EOT program including either the same bilateral vertical (CBV, n = 24) movement (squat) or different unilateral multidirectional (VUMD, n = 24) movements. Training programs consisted of 6 sets of 1 exercise (CBV) or 1 set of 6 exercises (VUMD) × 6-10 repetitions with 3 min of passive recovery between sets and exercises, biweekly for 8 wk. Functional-performance assessment included several change-of-direction (COD) tests, a 25-m linear-sprint test, unilateral multidirectional jumping tests (ie, lateral, horizontal, and vertical), and a bilateral vertical-jump test. Within-group analysis showed substantial improvements in all tests in both groups, with VUMD showing more robust adaptations in pooled COD tests and lateral/horizontal jumping, whereas the opposite occurred in CBV respecting linear sprinting and vertical jumping. Between-groups analyses showed substantially better results in lateral jumps (ES = 0.21), left-leg horizontal jump (ES = 0.35), and 10-m COD with right leg (ES = 0.42) in VUMD than in CBV. In contrast, left-leg countermovement jump (ES = 0.26) was possibly better in CBV than in VUMD. Eight weeks of EOT induced substantial improvements in functional-performance tests, although the force-vector application may play a key role to develop different and specific functional adaptations.

Effects of special exercise programs on functional movement screen scores and injury prevention in preprofessional young football players.

PubMed

Dinc, Engin; Kilinc, Bekir Eray; Bulat, Muge; Erten, Yunus Turgay; Bayraktar, Bülent

2017-10-01

To increase movement capacity and to reduce injury risk in young soccer players by implementing a special functional exercise program based on functional movement screen (FMS) and correctives. 67 young male athletes 14-19 years of age from a Super League Football Club Academy participated in the study. Functional movement patterns were evaluated with FMS assessment protocol. Deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, trunk stability push-up, and rotatory stability were examined in FMS. Considering the FMS scores the number of intervention and control groups were defined as 24 and 43, respectively. Intervention program was composed of 1 hr twice a week sessions in total of 12 weeks with 4 weeks of mobility, 4 weeks of stability, and 4 weeks of integration exercises. At the end of 12-week intervention and control groups were re-evaluated with FMS protocol. Contact and noncontact sports injuries recorded during one season. In intervention group there was statistically significant difference in increase in total FMS scores ( P <0.01), deep squat ( P ≤0.001), hurdle step ( P <0.05), inline lunge ( P <0.01), and trunk stability push-up ( P <0.01). In control group total FMS, deep squat, and trunk stability push-up scores increased with a statistical difference ( P <0.01, P <0.05, P ≤0.01, respectively). The incidence of noncontact injury in control group was higher than intervention group ( P <0.05). Periodic movement screening and proper corrections with functional training is valuable in order to create better movement capacity to build better physical performance and more effective injury prevention.

Physical Performance in Elite Male and Female Team Handball Players.

PubMed

Wagner, Herbert; Fuchs, Patrick; Fusco, Andrea; Fuchs, Philip; Bell, W Jeffrey; Duvillard, Serge P

2018-06-12

Biological differences between men and women are well known; however, literature-addressing knowledge about the influence of sex to specific and general performance in team handball is almost nonexistent. Consequently, the aim of the study was to assess and compare specific and general physical performance in male and female elite team handball players, to determine if the differences are consequential for general compared to specific physical performance characteristics and the relationship between general and specific physical performance. Twelve male and ten female elite team handball players performed a game based performance test, upper- und lower-body strength and power tests, a sprinting test, and an incremental treadmill-running test. Significant differences (P<.05) between male and female players were found for peak oxygen uptake and total running time during the treadmill test, 30m sprinting time, leg extension strength, trunk and shoulder rotation torque, counter movement jump height as well as offense and defense time, ball velocity and jump height in the game based performance test. An interaction (sex × test) was found for time and oxygen uptake and except shoulder rotation torque and ball velocity in females, we found only a low relationship between specific and general physical performance. The results of the study revealed that male players are heavier, taller, faster, stronger, jump higher and have a better aerobic performance. However, female players performed relatively better in the team handball specific tests compared to the general tests. Our findings also suggest that female players should focus more on strength training.

Effects of Small-Sided Games vs. Interval Training in Aerobic Fitness and Physical Enjoyment in Young Elite Soccer Players

PubMed Central

Martín, Juan; Lerga, Javier; Sánchez, Felipe; Villagra, Federico; Zulueta, Javier J.

2015-01-01

The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 ± 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 ± 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment. PMID:26331623

Understanding of empty container movement: A study on a bottleneck at an off-dock depot

NASA Astrophysics Data System (ADS)

Zain, Rosmaizura Mohd; Rahman, Mohd Nizam Ab; Nopiah, Zulkifli Mohd; Saibani, Nizaroyani

2014-09-01

Port not only function as connections between marine and land transportation but also as core business areas. In a port terminal, available space is limited, but the influx of container is growing. The off-dock depot is one of the key supply chain players that hold empty containers in the inventory. Therefore, this paper aims to identify the main factors of bottlenecks or congestion that hinder the rapid movement of empty containers from the off-dock depot to the customers. Thirty interviews were conducted with individuals who are key players in the container supply chain. The data were analyzed using Atlas.ti software and the analytic hierarchy process to rank the priority factors of bottlenecks. Findings show that several pertinent factors act as barriers to the key players in the container movement in the day-to-day operations. In future studies, strategies to overcome fragmentation in the container supply chain and logistics must be determined.

Computer games and fine motor skills.

PubMed

Borecki, Lukasz; Tolstych, Katarzyna; Pokorski, Mieczyslaw

2013-01-01

The study seeks to determine the influence of computer games on fine motor skills in young adults, an area of incomplete understanding and verification. We hypothesized that computer gaming could have a positive influence on basic motor skills, such as precision, aiming, speed, dexterity, or tremor. We examined 30 habitual game users (F/M - 3/27; age range 20-25 years) of the highly interactive game Counter Strike, in which players impersonate soldiers on a battlefield, and 30 age- and gender-matched subjects who declared never to play games. Selected tests from the Vienna Test System were used to assess fine motor skills and tremor. The results demonstrate that the game users scored appreciably better than the control subjects in all tests employed. In particular, the players did significantly better in the precision of arm-hand movements, as expressed by a lower time of errors, 1.6 ± 0.6 vs. 2.8 ± 0.6 s, a lower error rate, 13.6 ± 0.3 vs. 20.4 ± 2.2, and a shorter total time of performing a task, 14.6 ± 2.9 vs. 32.1 ± 4.5 s in non-players, respectively; p < 0.001 all. The findings demonstrate a positive influence of computer games on psychomotor functioning. We submit that playing computer games may be a useful training tool to increase fine motor skills and movement coordination.

Torque-angle-velocity Relationships and Muscle Performance of Professional and Youth Soccer Players.

PubMed

Mazuquin, B F; Dela Bela, L F; Pelegrinelli, A R M; Dias, J M; Carregaro, R L; Moura, F A; Selfe, J; Richards, J; Brown, L E; Cardoso, J R

2016-11-01

Soccer matches consist of a variety of different activities, including repeated sprints. Time to attain velocity (TTAV), load range (LR) and the torque-angle-velocity relationship (TAV 3D ) represent an important measurement of muscle performance, however there are few related studies. The aim of this study was to compare these outcomes between soccer players of different age category. 17 professional (PRO) and 17 under-17 (U17) soccer players were assessed for concentric knee flexion/extension at 60, 120 and 300°/s. For the extensor muscles, differences were found in favor of the U17 group for TTAV and LR outcomes at 120°/s, however, the PRO group maintained higher torques in both movement directions in comparison to the U17 in TAV 3D evaluation. These results suggest that muscle performance of the PRO group is more efficient than the U17 group. © Georg Thieme Verlag KG Stuttgart · New York.

Combined individual scrummaging kinetics and muscular power predict competitive team scrum success.

PubMed

Green, Andrew; Dafkin, Chloe; Kerr, Samantha; McKinon, Warrick

2017-09-01

Scrummaging is a major component of Rugby Union gameplay. Successful scrummaging is dependent on the coordination of the forward players and the strength of the eight individuals. The study aim was to determine whether individual scrummaging kinetics and other candidate factors associated with scrummaging performance discriminate team scrum performances. Sixteen club-level forwards (stature: 1.80 ± 0.1 m; mass: 99.0 ± 18.2 kg) were initially divided into two scrummaging packs. A total of 10 various scrum permutations were tested, where players were randomly swapped between the two packs. Winning scrums were determined by two observers on opposite sides of the scrum. Fatigue (100 mm visual analogue scale (VAS)) and scrummaging effort (6-20 rating of perceived exertion (RPE)) were assessed following each scrum contest. Individual scrummaging kinetics were acquired through an instrumented scrum ergometer and muscular power indicated through vertical jump heights. Student's t-tests were used to differentiate between winning and losing scrum packs. VAS and RPE were assessed using repeated measures ANOVAs. Winning scrum packs had significantly larger combined force magnitudes (p < .002), regardless of the player contribution calculations. Additionally, winning packs had less individual movement (p = .033) and higher combined vertical jump heights (p < .001) but were not significantly heavier (p = .759) than losing scrum packs. While perceived VAS and RPE values progressively increased (p < .001), no differences in the individual scrum magnitudes were observed between the 1st and 10th scrum (p = .418). The results indicated that the combination of individual forces, variation in movement and factors related to scrummaging performance, such as vertical jump height, were associated with team scrummaging success.

Wearable flex sensor system for multiple badminton player grip identification

NASA Astrophysics Data System (ADS)

Jacob, Alvin; Zakaria, Wan Nurshazwani Wan; Tomari, Mohd Razali Bin Md; Sek, Tee Kian; Suberi, Anis Azwani Muhd

2017-09-01

This paper focuses on the development of a wearable sensor system to identify the different types of badminton grip that is used by a player during training. Badminton movements and strokes are fast and dynamic, where most of the involved movement are difficult to identify with the naked eye. Also, the usage of high processing optometric motion capture system is expensive and causes computational burden. Therefore, this paper suggests the development of a sensorized glove using flex sensor to measure a badminton player's finger flexion angle. The proposed Hand Monitoring Module (HMM) is connected to a personal computer through Bluetooth to enable wireless data transmission. The usability and feasibility of the HMM to identify different grip types were examined through a series of experiments, where the system exhibited 70% detection ability for the five different grip type. The outcome plays a major role in training players to use the proper grips for a badminton stroke to achieve a more powerful and accurate stroke execution.

Selected Cognitive Abilities in Elite Youth Soccer Players

PubMed Central

Baláková, Veronika; Boschek, Petr; Skalíková, Lucie

2015-01-01

The identification of talent in soccer is critical to various programs. Although many research findings have been presented, there have been only a few attempts to assess their validity. The aim of this study was to determine the relationship between talent and achievement variables in the Vienna Test System. The participants were 91 Czech soccer players, representing four youth soccer teams, who were born in the year 2000. These boys were divided into two groups according to their coaches’ assessments using a TALENT questionnaire. A two-factor model (component 1: “kinetic finesse”; component 2: “mental strength”) was designed to interpret the responses of the coaches on the questionnaire. The Vienna Test System was used to determine the level of players’ cognitive abilities. In total, the subjects performed seven tests in the following order: Raven’s Standard Progressive Matrices (SPM), a reaction test (RT), a determination test (DT), a visual pursuit test (LVT), a Corsi Block-Tapping Test (CORSI), a time/movement anticipation test (ZBA), and a peripheral perception test (PP). To analyze the relationship between talent and achievement variables within the Vienna Test System, correlation analyses were performed. The results revealed that the talented group attained significantly better results on only 1 of the 16 variables, which was ZBA2: movement anticipation - deviation of movement median (r = .217, p = .019). A comparison of the two talent components showed that component 1 (“kinetic finesse”) was a more significant factor than component 2 (“mental strength”). Although we observed statistically significant correlations, their actual significance remains questionable; thus, further research is required. PMID:26839627

Physiological characteristics of elite and sub-elite badminton players.

PubMed

Ooi, Cheong Hwa; Tan, Albert; Ahmad, Azwari; Kwong, Kien Weng; Sompong, Ruji; Ghazali, Khairul Aswadi Mohd; Liew, Swee Lee; Chai, Wen Jin; Thompson, Martin William

2009-12-01

The aims of this study were to establish the physical and physiological attributes of elite and sub-elite Malaysian male badminton players and to determine whether these attributes discriminate elite players from sub-elite players. Measurements and tests of basic anthropometry, explosive power, anaerobic recovery capacity, badminton-specific movement agility, maximum strength, and aerobic capacity were conducted on two occasions, separated by at least one day. The elite (n = 12) and sub-elite (n = 12) players' characteristics were, respectively: mean age 24.6 years (s = 3.7) and 20.5 years (s = 0.7); mass 73.2 kg (s = 7.6) and 62.7 kg (s = 4.2); stature 1.76 m (s = 0.07) and 1.71 m (s = 0.05); body fat 12.5% (s = 4.8) and 9.5% (s = 3.4); estimated VO(2max) 56.9 ml . kg(-1) . min(-1) (s = 3.7) and 59.5 ml . kg(-1) . min(-1) (s = 5.2). The elite players had greater maximum absolute strength in one-repetition maximum bench press (P = 0.015) compared with the sub-elite players. There were significant differences in instantaneous lower body power estimated from vertical jump height between the elite and sub-elite groups (P < 0.01). However, there was no significant difference between groups in shuttle run tests and on-court badminton-specific movement agility tests. Our results show that elite Malaysian male badminton players are taller, heavier, and stronger than their sub-elite counterparts. The test battery, however, did not allow us to discriminate between the elite and sub-elite players, suggesting that at the elite level tactical knowledge, technical skills, and psychological readiness could be of greater importance.

Agreement Between Visual Assessment and 2-Dimensional Analysis During Jump Landing Among Healthy Female Athletes.

PubMed

Rabin, Alon; Einstein, Ofira; Kozol, Zvi

2018-04-01

  Altered movement patterns, including increased frontal-plane knee movement and decreased sagittal-plane hip and knee movement, have been associated with several knee disorders. Nevertheless, the ability of clinicians to visually detect such altered movement patterns during high-speed athletic tasks is relatively unknown.   To explore the association between visual assessment and 2-dimensional (2D) analysis of frontal-plane knee movement and sagittal-plane hip and knee movement during a jump-landing task among healthy female athletes.   Cross-sectional study.   Gymnasiums of participating volleyball teams.   A total of 39 healthy female volleyball players (age = 21.0 ± 5.2 years, height = 172.0 ± 8.6 cm, mass = 64.2 ± 7.2 kg) from Divisions I and II of the Israeli Volleyball Association.   Frontal-plane knee movement and sagittal-plane hip and knee movement during jump landing were visually rated as good, moderate, or poor based on previously established criteria. Frontal-plane knee excursion and sagittal-plane hip and knee excursions were measured using free motion-analysis software and compared among athletes with different visual ratings of the corresponding movements.   Participants with different visual ratings of frontal-plane knee movement displayed differences in 2D frontal-plane knee excursion ( P < .01), whereas participants with different visual ratings of sagittal-plane hip and knee movement displayed differences in 2D sagittal-plane hip and knee excursions ( P < .01).   Visual ratings of frontal-plane knee movement and sagittal-plane hip and knee movement were associated with differences in the corresponding 2D hip and knee excursions. Visual rating of these movements may serve as an initial screening tool for detecting altered movement patterns during jump landings.

Bilateral and Unilateral Asymmetries of Isokinetic Strength and Flexibility in Male Young Professional Soccer Players

PubMed Central

Daneshjoo, Abdolhamid; Rahnama, Nader; Mokhtar, Abdul Halim; Yusof, Ashril

2013-01-01

This study investigated bilateral and unilateral asymmetries of strength and flexibility in male young professional soccer players. Thirty-six soccer players (age: 18.9 ± 1.4 years) participated in this study. A Biodex Isokinetic Dynamometer was used to assess the hamstring and quadriceps strength at selected speeds of 60°/s, 180°/s and 300°/s. Hip joint flexibility was measured using a goniometer. No difference was observed in conventional strength ratio, dynamic control ratio and fast/slow speed ratio between the dominant and non-dominant legs (p>0.05). All but one of the players (97.2%) had musculoskeletal abnormality (bilateral imbalance > 10%) in one or more specific muscle groups. The dominant leg had greater hip joint flexibility compared with the non-dominant leg (108.8 ± 10.7° versus 104.6 ± 9.8°, respectively). The findings support the hypothesis that physical performance and movement pattern experienced during soccer playing may negatively change the balance of strength in both legs (bilateral strength balance), but not on the same leg of the young male professional soccer players. The results can be helpful for trainers and coaches to decide whether the players need to improve their balance and strength which in turn may prevent injury. It is suggested that in professional soccer training, quadriceps and hamstrings muscle strength, as well as hip joint flexibility should not be overlooked. PMID:23717354

Balance disorders caused by running and jumping occurring in young basketball players.

PubMed

Struzik, Artur; Zawadzki, Jerzy; Pietraszewski, Bogdan

2015-01-01

Body balance, as one of the coordination abilities,is a desirable variable for basketball players as regards the necessity of efficient responses in constantly changing situations on a basketball court. The aim of this study was to check whether physical activity in the form of running and jumping influences variables characterizing the process of keeping body balance of a basketball player in the standing position. The research was conducted on 11 young basketball players. The measurements were taken with a Kistler force plate. Apart from commonly registered COP displacements, an additional variable describing the process of keeping body balance by a basketball player was ankle joint stiffness on the basis of which an "Index of Balance-Stiffness" (IB-S) was created. Statistically significant differences were obtained for the maximum COP displacements and ankle joint stiffness between measurements of balance in the standing position before and after the employed movement tasks whereas there were no statistically significant differences for the aforementioned variables describing the process of keeping balance between measurements after running and after jumping. The research results indicate that the employed movement activities brought about significant changes in the process of keeping balance of basketball player in the standing position which, after the run performed, remain on a similar level to the series of jumps being performed. The authors attempted to establish an index based on the stiffness which yields a possibility to perceive each basketball player as an individual person in the process of keeping balance.

Movement Demands of Elite U20 International Rugby Union Players

PubMed Central

Drawer, Scott; Eager, Robin; Taylor, Neil; Cook, Christian

2016-01-01

The purpose of this study was to quantify movement demands of elite international age grade (U20) rugby union players during competitive tournament match play. Forty elite professional players from an U20 international performance squad were monitored using 10Hz global positioning systems (GPS) during 15 international tournament matches during the 2014/15 and 2015/16 seasons. Data on distances, velocities, accelerations, decelerations, high metabolic load (HML) distance and efforts, and number of sprints were derived. Data files from players who played over 60 min (n = 161) were separated firstly into Forwards and Backs, and more specifically into six positional groups; FR—Front Row (prop & hooker), SR—Second Row, BR—Back Row (Flankers & No.8), HB—Half Backs (scrum half & outside half), MF—Midfield (centres), B3 –Back Three (wings & full back) for match analysis. Analysis revealed significant differences between forwards and backs positions. Backs scored higher on all variables measured with the exception of number of moderate accelerations, decelerations (no difference). The centres covered the greatest total distance with the front row covering the least (6.51 ± 0.71 vs 4.97 ± 0.75 km, p < 0.001). The front row also covered the least high speed running (HSR) distance compared to the back three (211.6 ± 112.7 vs 728.4 ± 150.2 m, p < 0.001) who covered the most HSR distance, affirming that backs cover greater distances but forwards have greater contact loads. These findings highlight for the first time differences in the movement characteristics of elite age grade rugby union players specific to positional roles. PMID:27055230

Movement Demands of Elite U20 International Rugby Union Players.

PubMed

Cunningham, Daniel; Shearer, David A; Drawer, Scott; Eager, Robin; Taylor, Neil; Cook, Christian; Kilduff, Liam P

2016-01-01

The purpose of this study was to quantify movement demands of elite international age grade (U20) rugby union players during competitive tournament match play. Forty elite professional players from an U20 international performance squad were monitored using 10 Hz global positioning systems (GPS) during 15 international tournament matches during the 2014/15 and 2015/16 seasons. Data on distances, velocities, accelerations, decelerations, high metabolic load (HML) distance and efforts, and number of sprints were derived. Data files from players who played over 60 min (n = 161) were separated firstly into Forwards and Backs, and more specifically into six positional groups; FR--Front Row (prop & hooker), SR--Second Row, BR--Back Row (Flankers & No.8), HB--Half Backs (scrum half & outside half), MF--Midfield (centres), B3--Back Three (wings & full back) for match analysis. Analysis revealed significant differences between forwards and backs positions. Backs scored higher on all variables measured with the exception of number of moderate accelerations, decelerations (no difference). The centres covered the greatest total distance with the front row covering the least (6.51 ± 0.71 vs 4.97 ± 0.75 km, p < 0.001). The front row also covered the least high speed running (HSR) distance compared to the back three (211.6 ± 112.7 vs 728.4 ± 150.2 m, p < 0.001) who covered the most HSR distance, affirming that backs cover greater distances but forwards have greater contact loads. These findings highlight for the first time differences in the movement characteristics of elite age grade rugby union players specific to positional roles.

Longitudinal Study of Repeated Sprint Performance in Youth Soccer Players of Contrasting Skeletal Maturity Status

PubMed Central

Valente-dos-Santos, João; Coelho-e-Silva, Manuel J.; Severino, Vítor; Duarte, João; Martins, Raúl S.; Figueiredo, António J.; Seabra, André T.; Philippaerts, Renaat M.; Cumming, Sean P; Elferink-Gemser, Marije; Malina, Robert M.

2012-01-01

The purpose of the study was to evaluate the developmental changes in performance in a repeated-sprint ability (RSA) test in young soccer players of contrasting maturity status. A total of 83 regional level Portuguese youth soccer players, aged 11-13 years at baseline was assessed annually. Stature, body mass, 7x34.2-m sprint protocol (25-s active recovery), 20-m multi-stage continuous shuttle endurance run and counter-movement jump (CMJ) without the use of the arms were measured. Fat-free mass (FFM) was determined by age and gender-specific formulas. Developmental changes in total sprint time across ages were predicted using multilevel modeling. Corresponding measurements were performed on an independent cross-sectional subsample of 52 youth soccer players 11-17 years to evaluate the predictive model. CA, CA2, maturational status (SA-CA), body size (mass and stature), FFM, aerobic endurance, lower limb explosive strength and annual volume training significantly improved the statistical fit of the RSA multilevel model. In ‘late’ maturing athletes, the best model for predicting change in RSA was expressed by the following equation: 86.54 - 2.87 x CA + 0.05 x CA2 - 0.25 x FFM + 0.15 x body mass + 0.05 x stature - 0.05 x aerobic endurance - 0.09 x lower limb explosive strength - 0.01 x annual volume training. The best fitting models for players who were ‘on time’ and ‘early’ maturing were identical to the best model for late maturing players, less 0.64 seconds and 1.74 seconds, respectively. Multilevel modeling provided performance curves that permitted the prediction of individual RSA performance across adolescent years in regional level soccer players. Key pointsRepeated-sprint ability tests are a valuable sport-specific field test of sprint performance in youth soccer players. Here, the test had reasonable reliability and can be useful to trainers and coaches in the assessment of young athletes and in monitoring changes over time.The total sprint time of youth soccer players advanced in biological maturation improves more, on average, than that of players who are on time (average) and late in maturation. The performance difference between early and late maturing players is consistent after about 13 years of age.Multilevel modeling is a promising statistical technique for analyzing the development of functional capacity in a sport. It has the potential to provide useful information to assist trainers and coaches in evaluating and facilitating the development of individual players. PMID:24149342

Prediction of Lateral Ankle Sprains in Football Players Based on Clinical Tests and Body Mass Index.

PubMed

Gribble, Phillip A; Terada, Masafumi; Beard, Megan Q; Kosik, Kyle B; Lepley, Adam S; McCann, Ryan S; Pietrosimone, Brian G; Thomas, Abbey C

2016-02-01

The lateral ankle sprain (LAS) is the most common injury suffered in sports, especially in football. While suggested in some studies, a predictive role of clinical tests for LAS has not been established. To determine which clinical tests, focused on potentially modifiable factors of movement patterns and body mass index (BMI), could best demonstrate risk of LAS among high school and collegiate football players. Case-control study; Level of evidence, 3. A total of 539 high school and collegiate football players were evaluated during the preseason with the Star Excursion Balance Test (SEBT) and Functional Movement Screen as well as BMI. Results were compared between players who did and did not suffer an LAS during the season. Logistic regression analyses and calculated odds ratios were used to determine which measures predicted risk of LAS. The LAS group performed worse on the SEBT-anterior reaching direction (SEBT-ANT) and had higher BMI as compared with the noninjured group (P < .001). The strongest prediction models corresponded with the SEBT-ANT. Low performance on the SEBT-ANT predicted a risk of LAS in football players. BMI was also significantly higher in football players who sustained an LAS. Identifying clinical tools for successful LAS injury risk prediction will be a critical step toward the creation of effective prevention programs to reduce risk of sustaining an LAS during participation in football. © 2015 The Author(s).

Associations Between Rate of Force Development Metrics and Throwing Velocity in Elite Team Handball Players: a Short Research Report

PubMed Central

Marques, Mário C.; Saavedra, Francisco J.; Abrantes, Catarina; Aidar, Felipe J.

2011-01-01

Performance assessment has become an invaluable component of monitoring participant’s development in distinct sports, yet limited and contradictory data are available in trained subjects. The purpose of this study was to examine the relationship between ball throwing velocity during a 3-step running throw in elite team handball players and selected measures of rate of force development like force, power, velocity, and bar displacement during a concentric only bench press exercise in elite male handball players. Fitteen elite senior male team handball players volunteered to participate. Each volunteer had power and bar velocity measured during a concentric only bench press test with 25, 35, and 45 kg as well as having one-repetition maximum strength determined. Ball throwing velocity was evaluated with a standard 3-step running throw using a radar gun. The results of this study indicated significant associations between ball velocity and time at maximum rate of force development (0, 66; p<0.05) and rate of force development at peak force (0,56; p<0.05) only with 25kg load. The current research indicated that ball velocity was only median associated with maximum rate of force development with light loads. A training regimen designed to improve ball-throwing velocity in elite male team handball players should emphasize bench press movement using light loads. PMID:23487363

Associations between rate of force development metrics and throwing velocity in elite team handball players: a short research report.

PubMed

Marques, Mário C; Saavedra, Francisco J; Abrantes, Catarina; Aidar, Felipe J

2011-09-01

Performance assessment has become an invaluable component of monitoring participant's development in distinct sports, yet limited and contradictory data are available in trained subjects. The purpose of this study was to examine the relationship between ball throwing velocity during a 3-step running throw in elite team handball players and selected measures of rate of force development like force, power, velocity, and bar displacement during a concentric only bench press exercise in elite male handball players. Fitteen elite senior male team handball players volunteered to participate. Each volunteer had power and bar velocity measured during a concentric only bench press test with 25, 35, and 45 kg as well as having one-repetition maximum strength determined. Ball throwing velocity was evaluated with a standard 3-step running throw using a radar gun. The results of this study indicated significant associations between ball velocity and time at maximum rate of force development (0, 66; p<0.05) and rate of force development at peak force (0,56; p<0.05) only with 25kg load. The current research indicated that ball velocity was only median associated with maximum rate of force development with light loads. A training regimen designed to improve ball-throwing velocity in elite male team handball players should emphasize bench press movement using light loads.

Determinants of the half-turn with the ball in sub-elite youth soccer players.

PubMed

Zago, Matteo; Codari, Marina; Grilli, Massimo; Bellistri, Giuseppe; Lovecchio, Nicola; Sforza, Chiarella

2016-06-01

We explored the biomechanics of the 180° change-of-direction with the ball (half-turn) in soccer. We aimed at identifying movement strategies which enhance the players' half-turning performance, by characterising technique kinematics and understanding the structure of biomechanical and anthropometrics variables. Ten Under-13 sub-elite male players were recorded with an optoelectronic motion analyser while performing a 5-m straight dribbling followed by a half-turn with the sole. Joints kinematics differences between faster and slower trials were found in support-side hip rotation, driving-side hip adduction, trunk flexion and rotation, and arms abduction. To unveil the data-set structure, a principal component (PC) analysis and a stepwise linear discriminant analysis were performed using 30 biomechanical parameters and four anthropometric variables for each trial. Seven retained PCs explained 79% of the overall variability, featuring combinations of original variables that help in understanding the factors facilitating fast half-turns: keeping short steps, minimising lateral and forward body movements, and centre-of-mass lowering, even with ample lower limbs ranges of motion (RoM); abducting the upper limbs while limiting trunk flexion and pelvic inclination RoM. Balance and task-constrained exercises may be proposed to improve this technique. Moreover, a quantitative knowledge of the movement structure could give coaches objective insights to better instruct young players.

Optimising technical skills and physical loading in small-sided basketball games.

PubMed

Klusemann, Markus J; Pyne, David B; Foster, Carl; Drinkwater, Eric J

2012-01-01

Differences in physiological, physical, and technical demands of small-sided basketball games related to the number of players, court size, and work-to-rest ratios are not well characterised. A controlled trial was conducted to compare the influence of number of players (2v2/4v4), court size (half/full court) and work-to-rest ratios (4x2.5 min/2x5 min) on the demands of small-sided games. Sixteen elite male and female junior players (aged 15-19 years) completed eight variations of a small-sided game in randomised order over a six-week period. Heart rate responses and rating of perceived exertion (RPE) were measured to assess the physiological load. Movement patterns and technical elements were assessed by video analysis. There were ∼60% more technical elements in 2v2 and ∼20% more in half court games. Heart rate (86 ± 4% & 83 ± 5% of maximum; mean ± SD) and RPE (8 ± 2 & 6 ± 2; scale 1-10) were moderately higher in 2v2 than 4v4 small-sided games, respectively. The 2v2 format elicited substantially more sprints (36 ±12%; mean ±90% confidence limits) and high intensity shuffling (75 ±17%) than 4v4. Full court games required substantially more jogging (9 ±6%) compared to half court games. Fewer players in small-sided basketball games substantially increases the technical, physiological and physical demands.

Role of Gaze Cues in Interpersonal Motor Coordination: Towards Higher Affiliation in Human-Robot Interaction.

PubMed

Khoramshahi, Mahdi; Shukla, Ashwini; Raffard, Stéphane; Bardy, Benoît G; Billard, Aude

2016-01-01

The ability to follow one another's gaze plays an important role in our social cognition; especially when we synchronously perform tasks together. We investigate how gaze cues can improve performance in a simple coordination task (i.e., the mirror game), whereby two players mirror each other's hand motions. In this game, each player is either a leader or follower. To study the effect of gaze in a systematic manner, the leader's role is played by a robotic avatar. We contrast two conditions, in which the avatar provides or not explicit gaze cues that indicate the next location of its hand. Specifically, we investigated (a) whether participants are able to exploit these gaze cues to improve their coordination, (b) how gaze cues affect action prediction and temporal coordination, and (c) whether introducing active gaze behavior for avatars makes them more realistic and human-like (from the user point of view). 43 subjects participated in 8 trials of the mirror game. Each subject performed the game in the two conditions (with and without gaze cues). In this within-subject study, the order of the conditions was randomized across participants, and subjective assessment of the avatar's realism was assessed by administering a post-hoc questionnaire. When gaze cues were provided, a quantitative assessment of synchrony between participants and the avatar revealed a significant improvement in subject reaction-time (RT). This confirms our hypothesis that gaze cues improve the follower's ability to predict the avatar's action. An analysis of the pattern of frequency across the two players' hand movements reveals that the gaze cues improve the overall temporal coordination across the two players. Finally, analysis of the subjective evaluations from the questionnaires reveals that, in the presence of gaze cues, participants found it not only more human-like/realistic, but also easier to interact with the avatar. This work confirms that people can exploit gaze cues to predict another person's movements and to better coordinate their motions with their partners, even when the partner is a computer-animated avatar. Moreover, this study contributes further evidence that implementing biological features, here task-relevant gaze cues, enable the humanoid robotic avatar to appear more human-like, and thus increase the user's sense of affiliation.

Biomechanical Differences of Multidirectional Jump Landings Among Female Basketball and Soccer Players.

PubMed

Taylor, Jeffrey B; Ford, Kevin R; Schmitz, Randy J; Ross, Scott E; Ackerman, Terry A; Shultz, Sandra J

2017-11-01

Taylor, JB, Ford, KR, Schmitz, RJ, Ross, SE, Ackerman, TA, and Shultz, SJ. Biomechanical differences of multidirectional jump landings among female basketball and soccer players. J Strength Cond Res 31(11): 3034-3045, 2017-Anterior cruciate ligament (ACL) injury prevention programs are less successful in basketball than soccer and may be due to distinct movement strategies that these athletes develop from sport-specific training. The purpose of this study was to identify biomechanical differences between female basketball and soccer players during multidirectional jump landings. Lower extremity biomechanics of 89 female athletes who played competitive basketball (n = 40) or soccer (n = 49) at the middle- or high-school level were analyzed with 3-dimensional motion analysis during a drop vertical jump, double- (SAG-DL) and single-leg forward jump (SAG-SL), and double- (FRONT-DL) and single-leg (FRONT-SL) lateral jump. Basketball players landed with either less hip or knee, or both hip and knee excursion during all tasks (p ≤ 0.05) except for the SAGSL task, basketball players landed with greater peak hip flexion angles (p = 0.04). The FRONT-SL task elicited the most distinct sport-specific differences, including decreased hip adduction (p < 0.001) angles, increased hip internal rotation (p = 0.003), and increased relative knee external rotation (p = 0.001) excursions in basketball players. In addition, the FRONT-SL task elicited greater forces in knee abduction (p = 0.003) and lesser forces in hip adduction (p = 0.001) and knee external rotation (p < 0.001) in basketball players. Joint energetics were different during the FRONT-DL task, as basketball players exhibited less sagittal plane energy absorption at the hip (p < 0.001) and greater hip (p < 0.001) and knee (p = 0.001) joint stiffness. Sport-specific movement strategies were identified during all jump landing tasks, such that soccer players exhibited a more protective landing strategy than basketball players, justifying future efforts toward sport-specific ACL injury prevention programs.

The association between fundamental athletic movements and physical fitness in elite junior Australian footballers.

PubMed

Woods, Carl T; McKeown, Ian; Keogh, Justin; Robertson, Sam

2018-02-01

This study investigated the associations between fundamental athletic movement and physical fitness in junior Australian football (AF). Forty-four under 18 players performed a fundamental athletic movement assessment consisting of an overhead squat, double lunge, single leg Romanian deadlift and a push up. Movements were scored on three assessment criterions using a three-point scale. Additionally, participants performed five physical fitness tests commonly used for talent identification in AF. A Spearman's nonparametric correlation matrix was built, with correlation coefficients being visualised using a circularly rendered correlogram. Score on the overhead squat was moderately positively associated with dynamic vertical jump height on left (r s  = 0.40; P ≤ 0.05) and right (r s  = 0.30; P ≤ 0.05) leg take-off, stationary vertical jump (r s  = 0.32; P ≤ 0.05) and negatively associated with 20-m sprint time (r s  = -0.35; P ≤ 0.05). Score on the double lunge (left/right side) was moderately positively associated with the same physical fitness tests as well as score on the multistage fitness test. Results suggest that improvements in physical fitness qualities may occur through concurrent increases in fundamental athletic movement skill, namely the overhead squat and double lunge movements. These findings may assist with the identification and development of talent.

Asymmetry during preseason Functional Movement Screen testing is associated with injury during a junior Australian football season.

PubMed

Chalmers, Samuel; Fuller, Joel T; Debenedictis, Thomas A; Townsley, Samuel; Lynagh, Matthew; Gleeson, Cara; Zacharia, Andrew; Thomson, Stuart; Magarey, Mary

2017-07-01

The Functional Movement Screen (FMS) is a popular screening tool, however, the postulated relationship between prospective injury and FMS scoring remains sparsely explored in adolescent athletes. The aim of the study was to examine the association between pre-season FMS scores and injuries sustained during one regular season competition in elite adolescent Australian football players. Prospective cohort study. 237 elite junior Australian football players completed FMS testing during the late pre-season phase and had their weekly playing status monitored during the regular season. The definition of an injury was 'a trauma which caused a player to miss a competitive match'. The median composite FMS score was 14 (mean=13.5±2.3). An apriori analysis revealed that the presence of ≥1 asymmetrical sub-test was associated with a moderate increase in the risk of injury (hazard ratio=2.2 [1.0-4.8]; relative risk=1.9; p=0.047; sensitivity=78.4%; specificity=41.0%). Notably, post-hoc analysis identified that the presence of ≥2 asymmetrical sub-tests was associated with an even greater increase in risk of prospective injury (hazard ratio=3.7 [1.6-8.6]; relative risk=2.8; p=0.003; sensitivity=66.7%; specificity=78.0%). Achieving a composite score of ≤14 did not substantially increase the risk of prospective injury (hazard ratio=1.1 [0.5-2.1]; p=0.834). Junior Australian football players demonstrating asymmetrical movement during pre-season FMS testing were more likely to sustain an injury during the regular season than players without asymmetry. Findings suggest that the commonly reported composite FMS threshold score of ≤14 was not associated with injury in elite junior AF players. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Reliability of Wearable Inertial Measurement Units to Measure Physical Activity in Team Handball.

PubMed

Luteberget, Live S; Holme, Benjamin R; Spencer, Matt

2018-04-01

To assess the reliability and sensitivity of commercially available inertial measurement units to measure physical activity in team handball. Twenty-two handball players were instrumented with 2 inertial measurement units (OptimEye S5; Catapult Sports, Melbourne, Australia) taped together. They participated in either a laboratory assessment (n = 10) consisting of 7 team handball-specific tasks or field assessment (n = 12) conducted in 12 training sessions. Variables, including PlayerLoad™ and inertial movement analysis (IMA) magnitude and counts, were extracted from the manufacturers' software. IMA counts were divided into intensity bands of low (1.5-2.5 m·s -1 ), medium (2.5-3.5 m·s -1 ), high (>3.5 m·s -1 ), medium/high (>2.5 m·s -1 ), and total (>1.5 m·s -1 ). Reliability between devices and sensitivity was established using coefficient of variation (CV) and smallest worthwhile difference (SWD). Laboratory assessment: IMA magnitude showed a good reliability (CV = 3.1%) in well-controlled tasks. CV increased (4.4-6.7%) in more-complex tasks. Field assessment: Total IMA counts (CV = 1.8% and SWD = 2.5%), PlayerLoad (CV = 0.9% and SWD = 2.1%), and their associated variables (CV = 0.4-1.7%) showed a good reliability, well below the SWD. However, the CV of IMA increased when categorized into intensity bands (2.9-5.6%). The reliability of IMA counts was good when data were displayed as total, high, or medium/high counts. A good reliability for PlayerLoad and associated variables was evident. The CV of the previously mentioned variables was well below the SWD, suggesting that OptimEye's inertial measurement unit and its software are sensitive for use in team handball.

Game-Based Approaches' Pedagogical Principles: Exploring Task Constraints in Youth Soccer.

PubMed

Serra-Olivares, Jaime; González-Víllora, Sixto; García-López, Luis Miguel; Araújo, Duarte

2015-06-27

This study tested the use of two pedagogical principles of Game-based approaches, representation and exaggeration, in the context of game performance of U10 soccer players. Twenty-one players participated in two 3 vs. 3 small-sided games. The first small-sided game was modified by representation. The second small-sided game was modified by enhancing the penetration of the defense tactical problem for invasion games. Decision-making and execution were assessed using the Game Performance Evaluation Tool. No significant differences were observed between games in the number of decision-making units related to keeping possession, nor in those related to penetrating the defense. No significant differences were observed in any execution ability (ball control, passing, dribbling and get free movements). The findings suggested that both games could provide similar degeneracy processes to the players for skill acquisition (specific and contextualized task constraints in which they could develop their game performance and the capability to achieve different outcomes in varying contexts). Probably both games had similar learner-environment dynamics leading players to develop their capabilities for adapting their behaviours to the changing performance situations. More research is necessary, from the ecological dynamics point of view, to determine how we should use small-sided games in Game-based approaches.

Game-Based Approaches’ Pedagogical Principles: Exploring Task Constraints in Youth Soccer

PubMed Central

Serra-Olivares, Jaime; González-Víllora, Sixto; García-López, Luis Miguel; Araújo, Duarte

2015-01-01

This study tested the use of two pedagogical principles of Game-based approaches, representation and exaggeration, in the context of game performance of U10 soccer players. Twenty-one players participated in two 3 vs. 3 small-sided games. The first small-sided game was modified by representation. The second small-sided game was modified by enhancing the penetration of the defense tactical problem for invasion games. Decision-making and execution were assessed using the Game Performance Evaluation Tool. No significant differences were observed between games in the number of decision-making units related to keeping possession, nor in those related to penetrating the defense. No significant differences were observed in any execution ability (ball control, passing, dribbling and get free movements). The findings suggested that both games could provide similar degeneracy processes to the players for skill acquisition (specific and contextualized task constraints in which they could develop their game performance and the capability to achieve different outcomes in varying contexts). Probably both games had similar learner-environment dynamics leading players to develop their capabilities for adapting their behaviours to the changing performance situations. More research is necessary, from the ecological dynamics point of view, to determine how we should use small-sided games in Game-based approaches. PMID:26240668

A Comparison of Selected Kinematic Factors in Male Baseball and Female Fast Pitch Softball Batting.

ERIC Educational Resources Information Center

Spragg, Carolyn; Noble, Larry

Six female intercollegiate varsity softball players and six male intercollegiate varsity baseball players were filmed from overhead while batting a wiffle ball off a batting tee at hip height. Movements of the hips, trunk, upper body segments, and bat were analyzed. Group comparisons indicated that males had higher peak linear and, angular…

Trust My Face: Cognitive Factors of Head Fakes in Sports

ERIC Educational Resources Information Center

Kunde, Wilfried; Skirde, Stefanie; Weigelt, Matthias

2011-01-01

In many competitive sports, players try to deceive their opponents about their behavioral intentions by using specific body movements or postures called fakes. For example, fakes are performed in basketball when a player gazes in one direction but passes or shoots the ball in another direction to avert efficient defense actions. The present study…

Effects of an In-season Plyometric Training Program on Repeated Change of Direction and Sprint Performance in the Junior Soccer Player.

PubMed

Hammami, Mehréz; Negra, Yassine; Aouadi, Ridha; Shephard, Roy J; Chelly, Mohamed Souhaiel

2016-12-01

Hammami, M, Negra, Y, Aouadi, R, Shephard, RJ, and Chelly, MS. Effects of an in-season plyometric training program on repeated change of direction and sprint performance in the junior soccer player. J Strength Cond Res 30(12): 3312-3320, 2016-We aimed to determine the gains in explosive movements of male junior soccer players induced by incorporating an 8-week plyometric training program (PTP) into a standard soccer conditioning regimen 5 months after the beginning of the competitive season. Our hypothesis was that PTP would enhance explosive movements, and thus sprint running, repeated shuttle sprint ability (RSSA), agility and the ability to make repeated changes of direction (RCOD). A group of junior soccer players were randomly divided into 2 groups: an experimental group (E, n = 15, age 15.7 ± 0.2 years) and a control group (C, n = 13, age 15.8 ± 0.2 years). The participants in E and C performed training exercises and matches together, but for an 8-week period in the latter part of the season, the experimental group replaced a part of the normal regimen (the tactical session) by a biweekly course of PTP (hurdle and drop jumps). Two familiarization sessions were held 2 weeks before definitive testing. The ability of the players was assessed by 3 agility tests (a sprint test with 180° turns, a 9-3-6-3-9 m sprint with backward and forward running, and a four 5-m sprint test with turns); 2 repeated sprint tests (RSSA and RCOD); and running times over 5-, 10-, 20-, 30-, and 40-m distances. Participants in E showed gains relative to C in sprint times (p ≤ 0.05 for 5, 10, and 20 m), and 2 of 3 the RCOD parameters (RCOD best, p ≤ 0.001; RCOD total, p ≤ 0.05). However, with the pattern of plyometric training that we adopted, and perhaps because participants were in good initial physical condition, the agility and RSSA test scores remained unchanged. Nevertheless, we conclude that our PTP can be commended to junior soccer players as a means of improving important components of their physical performance.

Influence of field size on the physiological and skill demands of small-sided games in junior and senior rugby league players.

PubMed

Gabbett, Tim J; Abernethy, Bruce; Jenkins, David G

2012-02-01

The purpose of this study was to investigate the effect of changes in field size on the physiological and skill demands of small-sided games in elite junior and senior rugby league players. Sixteen elite senior rugby league players ([mean ± SE] age, 23.6 ± 0.5 years) and 16 elite junior rugby league players ([mean ± SE] age, 17.3 ± 0.3 years) participated in this study. On day 1, 2 teams played an 8-minute small-sided game on a small field (10-m width × 40-m length), whereas the remaining 2 teams played the small-sided game on a larger sized field (40-m width × 70-m length). On day 2, the groups were crossed over. Movement was recorded by a global positioning system unit sampling at 5 Hz. Games were filmed to count the number of possessions and the number and quality of disposals. The games played on a larger field resulted in a greater (p < 0.05) total distance covered, and distances covered in moderate, high, and very-high velocity movement intensities. Senior players covered more distance at moderate, high, and very-high intensities, and less distance at low and very-low intensities during small-sided games than junior players. Although increasing field size had no significant influence (p > 0.05) over the duration of recovery periods for junior players, larger field size significantly reduced (p < 0.05) the amount of short-, moderate-, and long-duration recovery periods in senior players. No significant between-group differences (p > 0.05) were detected for games played on a small or large field for the number or quality of skill involvements. These results suggest that increases in field size serve to increase the physiological demands of small-sided games but have minimal influence over the volume or quality of skill executions in elite rugby league players.

Influence of shoe midsole hardness on plantar pressure distribution in four basketball-related movements.

PubMed

Lam, Wing-Kai; Ng, Wei Xuan; Kong, Pui Wah

2017-01-01

This study examined how shoe midsole hardness influenced plantar pressure in basketball-related movements. Twenty male university basketball players wore customized shoes with hard and soft midsoles (60 and 50 Shore C) to perform four movements: running, maximal forward sprinting, maximal 45° cutting and lay-up. Plantar loading was recorded using an in-shoe pressure measuring system, with peak pressure (PP) and pressure time integral (PTI) extracted from 10 plantar regions. Compared with hard shoes, subjects exhibited lower PP in one or more plantar regions when wearing the soft shoes across all tested movements (Ps < 0.05). Lower PTI was also observed in the hallux for 45° cutting, and the toes and forefoot regions during the first step of lay-up in the soft shoe condition (Ps < 0.05). In conclusion, using a softer midsole in the forefoot region may be a plausible remedy to reduce the high plantar loading experienced by basketball players.

Impact of Fatigue on Positional Movements During Professional Rugby Union Match Play.

PubMed

Tee, Jason C; Lambert, Mike I; Coopoo, Yoga

2017-04-01

In team sports, fatigue is manifested by a self-regulated decrease in movement distance and intensity. There is currently limited information on the effect of fatigue on movement patterns in rugby union match play, particularly for players in different position groups (backs vs forwards). This study investigated the effect of different match periods on movement patterns of professional rugby union players. Global positioning system (GPS) data were collected from 46 professional match participations to determine temporal effects on movement patterns. Total relative distance (m/min) was decreased in the 2nd half for both forwards (-13%, ±8%, ES = very likely large) and backs (-9%, ±7%, ES = very likely large). A larger reduction in high-intensity-running distance in the 2nd half was observed for forwards (-27%, ±16%, ES = very likely medium) than for backs (-10%, ±15%; ES = unclear). Similar patterns were observed for sprint (>6 m/s) frequency (forwards -29%, ±29%, ES = likely small vs backs -13% ±18%, ES = possibly small) and acceleration (>2.75 m/s 2 ) frequency (forwards -27%, ±24%, ES = likely medium vs backs -5%, ±46%, ES = unclear). Analysis of 1st- and 2nd-half quartiles revealed differing pacing strategies for forwards and backs. Forwards display a "slow-positive" pacing strategy, while the pacing strategy of backs is "flat." Forwards suffered progressively greater performance decrements over the course of the match, while backs were able to maintain performance intensity. These findings reflect differing physical demands, notably contact and running loads, of players in different positions.

Leadership in moving human groups.

PubMed

Boos, Margarete; Pritz, Johannes; Lange, Simon; Belz, Michael

2014-04-01

How is movement of individuals coordinated as a group? This is a fundamental question of social behaviour, encompassing phenomena such as bird flocking, fish schooling, and the innumerable activities in human groups that require people to synchronise their actions. We have developed an experimental paradigm, the HoneyComb computer-based multi-client game, to empirically investigate human movement coordination and leadership. Using economic games as a model, we set monetary incentives to motivate players on a virtual playfield to reach goals via players' movements. We asked whether (I) humans coordinate their movements when information is limited to an individual group member's observation of adjacent group member motion, (II) whether an informed group minority can lead an uninformed group majority to the minority's goal, and if so, (III) how this minority exerts its influence. We showed that in a human group--on the basis of movement alone--a minority can successfully lead a majority. Minorities lead successfully when (a) their members choose similar initial steps towards their goal field and (b) they are among the first in the whole group to make a move. Using our approach, we empirically demonstrate that the rules of swarming behaviour apply to humans. Even complex human behaviour, such as leadership and directed group movement, follow simple rules that are based on visual perception of local movement.

The locomotor activity of soccer players based on playing positions during the 2010 World Cup.

PubMed

Soroka, Andrzej

2018-06-01

The aim of this study was to define the locomotor activity of footballer players during the 2010 World Cup and to assess what differences existed among different playing positions. Research was conducted using research material collected from the Castrol Performance Index, a kinematic game analysis system that records player movements during a game by use of semi-automatic cameras. A total of 599 players who participated in the championships were analyzed. The results were evaluated using one-way analysis of variance (ANOVA) and a post-hoc test that calculated the Honestly Significant Difference (HSD) in order to determine which mean values significantly differed among the player positions. It was found that midfielders covered on average the largest distance during a match (10,777.6 m, P<0.001) as well as performing the most locomotor activity at high and sprint intensities (2936.8 m and 108.4 m, respectively). Additionally, midfielders also spent the largest amount of time at performing at a high intensity (10.6%). Strikers also featured high levels of the above parameters; the total length of distance covered with high intensities was found to be on average 2586.7 m, the distance covered at sprint intensity was 105 m. The footballers, playing at the championship level feature excellent locomotor preparation. This fact is undoubtedly supported by the aerobic training of high intensity. Such training allows footballers to extend the distance they cover during the match, increase the intensity of locomotor activities and sprint speed distance.

Increased Inhibition in Non-Primary Motor Areas of String-Instrument Players: A Preliminary Study with Paired-Pulse Transcranial Magnetic Stimulation

PubMed Central

Vaalto, Selja; Julkunen, Petro; Säïsänen, Laura; Könönen, Mervi; Määttä, Sara; Karhu, Jari

2016-01-01

Background: The muscle representations in non-primary motor area (NPMA) are located in the dorsal premotor area (PMd) and in the border region between the premotor area and the supplementary motor area (SMA). Objective: We characterized the plasticity of intracortical inhibitory and excitatory circuits in muscle representations in primary motor cortex (M1) and in NPMA related to acquired fine motor skills. We compared local cortical inhibition and facilitation balance in M1 and in NPMA between control subjects (n = 6) and right-handed string-instrument players (n = 5). Methods: Navigated transcranial magnetic stimulation (TMS) was used to compare motor thresholds (MTs), motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in non-dominant hand muscle representations in M1 and NPMA. Results: String-instrument players showed reduced SICI in M1 in the actively used left hand abductor digiti minimi (ADM) muscle representation at 3 ms inter-stimulus interval (ISI) with a conditioning stimulus (CS) intensity of 80% of MT and increased SICI in NPMA in ADM representation at 2 ms ISI and CS intensity of 50% of MT in comparison with controls. No differences between string-instrument players and controls were found for the SICI in the left hand opponens pollicis (OP) muscle representation, which is a muscle not intensively trained in string-instrument players. Conclusions: These preliminary results indicate that the stronger inhibition in motor representations outside M1 in string-instrument players may be crucial when accurate movements of single muscles must be performed. In contrast, weaker inhibition in M1 in string-instrument players may benefit the performance of fast finger movements. PMID:29765844

Improving fitness of elite handball players: small-sided games vs. high-intensity intermittent training.

PubMed

Iacono, Antonio Dello; Eliakim, Alon; Meckel, Yoav

2015-03-01

The present study was designed to compare the effects of high-intensity intermittent training (HIIT) and small-sided games (SSGs) training on fitness variables of elite handball players. Eighteen highly trained players (mean age ± SD: 25.6 ± 0.5 years) were assigned to either HIIT or SSGs group training protocols twice per week for 8 weeks. The HIIT consisted of 12-24 × 15 seconds of high-intensity runs interspersed by 15 seconds of recovery. The SSGs training consisted of 3 against 3 small-sided handball games. Both training methods were matched for exercise duration and recovery at each training session. Before and after 8-week training, the following fitness variables were assessed-speed: 10- and 20-m sprint time, agility: handball agility specific test (HAST), upper arm strength: 1 repetition maximum (1RM) bench press test, lower limb power: counter-movement jump tests with (CMJarm) and without (CMJ) arm movement, and aerobic fitness (yo-yo intermittent recovery test level 1 [YYIRTL1]). Significant improvement was found in the YYIRTL1 (23.3 and 26.3%, respectively), 10-m sprint (2.3 and 4.1%, respectively) and 20-m sprint (2.1 and 4%, respectively), HAST (1.1 and 2.2%, respectively), 1RM bench press (6.8 and 12.3%, respectively), CMJ (7.4 and 10.8%, respectively), and CMJarm (6.4 and 8.9%, respectively) following training in both groups (p ≤ 0.05 for all). There was a significantly greater improvement in 10- and 20-m sprint, HAST, 1RM, CMJ, and CMJarm following the SSGs training compared with the HIIT (p ≤ 0.05 for all). These results indicated that both HIIT and SSGs are effective training methods for fitness development among elite adult handball players. However, SSGs training may be considered as the preferred training regimen for improving handball-specific fitness variables during the in-season period.

Physical Demands of Representative Match-Play in Adolescent Rugby Union.

PubMed

Read, Dale B; Jones, Ben; Phibbs, Padraic J; Roe, Gregory A B; Darrall-Jones, Joshua D; Weakley, Jonathon J S; Till, Kevin

2017-05-01

Read, DB, Jones, B, Phibbs, PJ, Roe, GAB, Darrall-Jones, J, Weakley, JJS, and Till, K. Physical demands of representative match-play in adolescent rugby union. J Strength Cond Res 31(5): 1290-1296, 2017-The purpose of this study was to quantify the physical demands of representative adolescent rugby union match-play and investigate the difference between playing positions and age groups. Players (n = 112) were classified into 6 groups by playing position (forwards and backs) and age group (U16, U18, and U20). The physical demands were measured using microsensor-based technology and analyzed using magnitude-based inferences to assess practical importance. Backs had a greater relative distance (except U16s) and a greater high-speed running distance per minute than forwards, with the magnitude of difference between the positions becoming larger in older age groups. Forwards had higher values of PlayerLoad (PL) per minute (accumulated accelerations from the 3 axes of movement) and PL slow per minute (accumulated accelerations from the 3 axes of movement where velocity is <2 m·s) than backs at all age groups. Relative distance, low-, and high-speed running per minute all had a trend to be lower in older age groups for both positions. PlayerLoad per minute was greater in U18 than that in U16 and U20 for both positions. PlayerLoad slow per minute was greater for older age groups besides the U18 and U20 comparisons, which were unclear. The contrasts in physical demands experienced by different positions reinforce the need for greater exposure to sprinting and collision-based activity for backs and forwards, respectively. Given PL metrics peak at U18 and locomotor demands seem to be lower in older ages, the demands of representative adolescent rugby union do not seem to be greater at U20 as expected.

Efficiently detecting outlying behavior in video-game players.

PubMed

Kim, Young Bin; Kang, Shin Jin; Lee, Sang Hyeok; Jung, Jang Young; Kam, Hyeong Ryeol; Lee, Jung; Kim, Young Sun; Lee, Joonsoo; Kim, Chang Hun

2015-01-01

In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players' characteristics. These characteristics are captured non-invasively in a general game environment. In this paper, cameras were used to analyze observed data such as facial expressions and player movements. Moreover, multimodal data from the game players (i.e., data regarding adjustments to the volume and the use of the keyboard and mouse) was used to analyze high-dimensional game-player data. A support vector machine was used to efficiently detect outlying behaviors. We verified the effectiveness of the proposed method using games from several genres. The recall rate of the outlying behavior pre-identified by industry experts was approximately 70%. The proposed method can also be used for feedback analysis of various interactive content provided in PC environments.

The influence of tennis court surfaces on player perceptions and biomechanical response.

PubMed

Starbuck, Chelsea; Damm, Loïc; Clarke, James; Carré, Matt; Capel-Davis, Jamie; Miller, Stuart; Stiles, Victoria; Dixon, Sharon

2016-09-01

This study aimed to examine player perceptions and biomechanical responses to tennis surfaces and to evaluate the influence of prior clay court experience. Two groups with different clay experiences (experience group, n = 5 and low-experience group, n = 5) performed a 180° turning movement. Three-dimensional ankle and knee movements (50 Hz), plantar pressure of the turning step (100 Hz) and perception data (visual analogue scale questionnaire) were collected for two tennis courts (acrylic and clay). Greater initial knee flexion (acrylic 20. 8 ± 11.2° and clay 32.5 ± 9.4°) and a more upright position were reported on the clay compared to the acrylic court (P < 0.05). This suggests adaptations to increase player stability on clay. Greater hallux pressures and lower midfoot pressures were observed on the clay court, allowing for sliding whilst providing grip at the forefoot. Players with prior clay court experience exhibited later peak knee flexion compared to those with low experience. All participants perceived the differences in surface properties between courts and thus responded appropriately to these differences. The level of previous clay court experience did not influence players' perceptions of the surfaces; however, those with greater clay court experience may reduce injury risk as a result of reduced loading through later peak knee flexion.

From eye movements to actions: how batsmen hit the ball.

PubMed

Land, M F; McLeod, P

2000-12-01

In cricket, a batsman watches a fast bowler's ball come toward him at a high and unpredictable speed, bouncing off ground of uncertain hardness. Although he views the trajectory for little more than half a second, he can accurately judge where and when the ball will reach him. Batsmen's eye movements monitor the moment when the ball is released, make a predictive saccade to the place where they expect it to hit the ground, wait for it to bounce, and follow its trajectory for 100-200 ms after the bounce. We show how information provided by these fixations may allow precise prediction of the ball's timing and placement. Comparing players with different skill levels, we found that a short latency for the first saccade distinguished good from poor batsmen, and that a cricket player's eye movement strategy contributes to his skill in the game.

PA03.05. Masha taila as a preventive measure in gulpha marma injuries.

PubMed Central

Dhaded, Rajani; Kulkarni, BG

2013-01-01

Purpose: In Basketball game Gulpha Marma injuries are common. Wrong landing causes inflammation & tearing of ligament resulting into sprain. Prevention can be carried out by protective wears like Ankelet,crape bandge which gives temporary recovery. Assessment and evaluation of the application of Masha Taila as a Snehana and Avagaha Sweda as a preventive measure for Gulpha Marma injuries. Method: 30 players with Normal ankle joint (Group A) & 30 players with Ankle sprain (1st degree) of Basketball players (Group B) were taken with age group 13 to 25 yrs. Goniometer to measure Range of motion (R.O.M.), pain analog scale for pain gradation. Result: Group A and B were compared with their control groups. The statistical result for normal dorsiflexion was 0.0007 degree, plantar flexion 0.001 degree, dorsi flexion of ankle sprain players 0.002 degree, plantar flexion 0.03 degree. The measurement of ROM of all players increased by 510 times indicating increased joint flexibility, based on ROM Mash taila proved to be a preventive measure. Pain analog scale for group B players indicated moderate pain at 0 day,reduced by 50% on 15th day and completely reduced on 30th day. Conclusion: “Prevention is better than cure”. As a preventive aspect the application of Masha Taila in normal ankle joint as Snehan & Swedan with warm water increases flexibility of joint and muscle strength. In sprained joint the same Taila application relives pain and regains its movements, this recovery and strength of joints happens because of reduce adhesion & influence the direction of new collage fibres in the healing process. It eliminates toxic accumulation from secondary muscle spasm. These Marma being the vital points must be prevented by applying Snehan & Swedan before starting the game just as warm up.

Increased Complexities in Visual Search Behavior in Skilled Players for a Self-Paced Aiming Task

PubMed Central

Chia, Jingyi S.; Burns, Stephen F.; Barrett, Laura A.; Chow, Jia Y.

2017-01-01

The badminton serve is an important shot for winning a rally in a match. It combines good technique with the ability to accurately integrate visual information from the shuttle, racket, opponent, and intended landing point. Despite its importance and repercussive nature, to date no study has looked at the visual search behaviors during badminton service in the singles discipline. Unlike anticipatory tasks (e.g., shot returns), the serve presents an opportunity to explore the role of visual search behaviors in movement control for self-paced tasks. Accordingly, this study examined skill-related differences in visual behavior during the badminton singles serve. Skilled (n = 12) and less skilled (n = 12) participants performed 30 serves to a live opponent, while real-time eye movements were captured using a mobile gaze registration system. Frame-by-frame analyses of 662 serves were made and the skilled players took a longer preparatory time before serving. Visual behavior of the skilled players was characterized by significantly greater number of fixations on more areas of interest per trial than the less skilled. In addition, the skilled players spent a significantly longer time fixating on the court and net, whereas the less skilled players found the shuttle to be more informative. Quiet eye (QE) duration (indicative of superior sports performance) however, did not differ significantly between groups which has implications on the perceived importance of QE in the badminton serve. Moreover, while visual behavior differed by skill level, considerable individual differences were also observed especially within the skilled players. This augments the need for not just group-level analyses, but individualized analysis for a more accurate representation of visual behavior. Findings from this study thus provide an insight to the possible visual search strategies as players serve in net-barrier games. Moreover, this study highlighted an important aspect of badminton relating to deception and the implications of interpreting visual behavior of players. PMID:28659850

Increased Complexities in Visual Search Behavior in Skilled Players for a Self-Paced Aiming Task.

PubMed

Chia, Jingyi S; Burns, Stephen F; Barrett, Laura A; Chow, Jia Y

2017-01-01

The badminton serve is an important shot for winning a rally in a match. It combines good technique with the ability to accurately integrate visual information from the shuttle, racket, opponent, and intended landing point. Despite its importance and repercussive nature, to date no study has looked at the visual search behaviors during badminton service in the singles discipline. Unlike anticipatory tasks (e.g., shot returns), the serve presents an opportunity to explore the role of visual search behaviors in movement control for self-paced tasks. Accordingly, this study examined skill-related differences in visual behavior during the badminton singles serve. Skilled ( n = 12) and less skilled ( n = 12) participants performed 30 serves to a live opponent, while real-time eye movements were captured using a mobile gaze registration system. Frame-by-frame analyses of 662 serves were made and the skilled players took a longer preparatory time before serving. Visual behavior of the skilled players was characterized by significantly greater number of fixations on more areas of interest per trial than the less skilled. In addition, the skilled players spent a significantly longer time fixating on the court and net, whereas the less skilled players found the shuttle to be more informative. Quiet eye (QE) duration (indicative of superior sports performance) however, did not differ significantly between groups which has implications on the perceived importance of QE in the badminton serve. Moreover, while visual behavior differed by skill level, considerable individual differences were also observed especially within the skilled players. This augments the need for not just group-level analyses, but individualized analysis for a more accurate representation of visual behavior. Findings from this study thus provide an insight to the possible visual search strategies as players serve in net-barrier games. Moreover, this study highlighted an important aspect of badminton relating to deception and the implications of interpreting visual behavior of players.

Anthropometric and performance measures to study talent detection in youth volleyball.

PubMed

Melchiorri, Giovanni; Viero, Valerio; Triossi, Tamara; Annino, Giuseppe; Padua, Elvira; Tancredi, Virginia

2017-12-01

The aim of this work was to study anthropometric and performance measurements in 60 young male volleyball players (YV) and 60 youth not active in the sport (YNA) to assess which of these would be more useful to study the characteristics of potential performers. Eight measures to assess anthropometric characteristics, six performance measures and two tests for joint mobility were used. Also relative age and level of maturation were assessed. The anthropometric variables, relative age and level of maturation measured did not show statistically significant differences between groups. The YV and YNA groups showed differences in the performance measures. YV group was characterized by a better performance of the ability to repeat short sprints, of the upper limbs, abdominal muscles and lower limbs, with a medium effect size (Shuttle Running Test: 0.6; Push-Up: 0.5; Sit-Up: 0.4; counter movement jump: 0.4). These performance variables were very sensitive and specific: the SRT measurement had the best positive likelihood ratio that indicates the utility of the test in identifying type of players (YV and YNA). In talent detection in youth volleyball, in the 11-13 age range, performance variables should be preferred to anthropometric ones.

Neuromuscular Risk Factors for Knee and Ankle Ligament Injuries in Male Youth Soccer Players.

PubMed

Read, Paul J; Oliver, Jon L; De Ste Croix, Mark B A; Myer, Gregory D; Lloyd, Rhodri S

2016-08-01

Injuries reported in male youth soccer players most commonly occur in the lower extremities, and include a high proportion of ligament sprains at the ankle and knee with a lower proportion of overuse injuries. There is currently a paucity of available literature that examines age- and sex-specific injury risk factors for such injuries within youth soccer players. Epidemiological data have reported movements that lead to non-contact ligament injury include running, twisting and turning, over-reaching and landing. Altered neuromuscular control during these actions has been suggested as a key mechanism in females and adult populations; however, data available in male soccer players is sparse. The focus of this article is to review the available literature and elucidate prevalent risk factors pertaining to male youth soccer players which may contribute to their relative risk of injury.

Quantifying movement demands of AFL football using GPS tracking.

PubMed

Wisbey, Ben; Montgomery, Paul G; Pyne, David B; Rattray, Ben

2010-09-01

Global positioning system (GPS) monitoring of movement patterns is widespread in elite football including the Australian Football League (AFL). However documented analysis of this activity is lacking. We quantified the movement patterns of AFL football and differences between nomadic (midfield), forward and defender playing positions, and determined whether the physical demands have increased over a four season period. Selected premiership games were monitored during the 2005 (n=80 game files), 2006 (n=244), 2007 (n=632) and 2008 (n=793) AFL seasons. Players were fitted with a shoulder harness containing a GPS unit. GPS data were downloaded after games and the following measures extracted: total distance (km), time in various speed zones, maximum speed, number of surges, accelerations, longest continuous efforts and a derived exertion index representing playing intensity. In 2008 nomadic players covered per game 3.4% more total distance (km), had 4.8% less playing time (min), a 17% higher exertion index (per min), and 23% more time running >18kmh(-1) than forwards and defenders (all p<0.05). Physical demands were substantially higher in the 2008 season compared with 2005: an 8.4% increase in mean speed, a 14% increase in intensity (exertion index) and a 9.0% decrease in playing time (all p<0.05). Nomadic players in AFL work substantially harder than forwards and defenders in covering more ground and at higher running intensities. Increases in the physical demands of AFL football were evident between 2005 and 2008. The increasing speed of the game has implications for game authorities, players and coaching staff.

Enhancing the control of force in putting by video game training.

PubMed

Fery, Y A; Ponserre, S

2001-10-10

Even if golf video games provide no proprioceptive afferences on actual putting movement, they may give sufficient substitutive visual cues to enhance force control in this skill. It was hypothesized that this usefulness requires, however, two conditions: the video game must provide reliable demonstrations of actual putts, and the user must want to use the game to make progress in actual putting. Accordingly, a video game was selected on the basis of its fidelity to the real-world game. It allowed two different methods of adjusting the virtual player's putting force in order to hole a putt: an analogue method that consisted of focusing on the virtual player's movement and a symbolic method that consisted of focusing on the movement of a gauge on a scale representing the virtual player's putting force. The participants had to use one of these methods with either the intention of making progress in actual putting or in a second condition to simply enjoy the game. Results showed a positive transfer of video playing to actual putting skill for the learning group and also, to a lesser degree, for the enjoyment group; but only when they used the symbolic method. Results are discussed in the context of how vision may convey force cues in sports video games.

Distinct cut task strategy in Australian football players with a history of groin pain.

PubMed

Edwards, Suzi; Brooke, Hiram C; Cook, Jill L

2017-01-01

This study aimed to explore the differences in the magnitude of movement variability and strategies utilized during an unanticipated cut task between players with and without a history of groin pain. Cross-sectional design. Biomechanics laboratory. Male Australian football players with (HISTORY; n = 7) or without (CONTROL; n = 10) a history of groin pain. Three-dimensional ground reaction forces (GRF) and kinematics were recorded during 10 successful trials of an unanticipated cut task, and isokinetic hip adduction and abduction strength. Between-group differences were determined using independent-samples t-tests and the coefficient of variation (CV). Key substantial between-group differences identified were that the HISTORY group displayed decreased knee flexion and hip internal rotation, increased knee internal rotation and T12-L1 right rotation, and higher GRFs during the cut task. They also utilized three invariant systems (ankle, knee and T12-L1 joints), while being connected by a segment (hip and L5-S1 joints) that displayed increased lumbopelvic movement during the cut task, and decreased adductor muscle strength. This identifies the need for clinical management of the lower limb and thoracic segment to improve functional movement patterns in athletes with a history of a groin injury. Copyright © 2016 Elsevier Ltd. All rights reserved.

Muscle damage produced during a simulated badminton match in competitive male players.

PubMed

Abián, Pablo; Del Coso, Juan; Salinero, Juan José; Gallo-Salazar, César; Areces, Francisco; Ruiz-Vicente, Diana; Lara, Beatriz; Soriano, Lidón; Muñoz, Victor; Lorenzo-Capella, Irma; Abián-Vicén, Javier

2016-01-01

The purpose of the study was to assess the occurrence of muscle damage after a simulated badminton match and its influence on physical and haematological parameters. Sixteen competitive male badminton players participated in the study. Before and just after a 45-min simulated badminton match, maximal isometric force and badminton-specific running/movement velocity were measured to assess muscle fatigue. Blood samples were also obtained before and after the match. The badminton match did not affect maximal isometric force or badminton-specific velocity. Blood volume and plasma volume were significantly reduced during the match and consequently haematite, leucocyte, and platelet counts significantly increased. Blood myoglobin and creatine kinase concentrations increased from 26.5 ± 11.6 to 197.3 ± 70.2 µg·L(-1) and from 258.6 ± 192.2 to 466.0 ± 296.5 U·L(-1), respectively. In conclusion, a simulated badminton match modified haematological parameters of whole blood and serum blood that indicate the occurrence of muscle fibre damage. However, the level of muscle damage did not produce decreased muscle performance.

Reliability of Triaxial Accelerometry for Measuring Load in Men's Collegiate Ice Hockey.

PubMed

Van Iterson, Erik H; Fitzgerald, John S; Dietz, Calvin C; Snyder, Eric M; Peterson, Ben J

2017-05-01

Van Iterson, EH, Fitzgerald, JS, Dietz, CC, Snyder, EM, and Peterson, BJ. Reliability of triaxial accelerometry for measuring load in men's collegiate ice hockey. J Strength Cond Res 31(5): 1305-1312, 2017-Wearable microsensor technology incorporating triaxial accelerometry is used to quantify an index of mechanical stress associated with sport-specific movements termed PlayerLoad. The test-retest reliability of PlayerLoad in the environmental setting of ice hockey is unknown. The primary aim of this study was to quantify the test-retest reliability of PlayerLoad in ice hockey players during performance of tasks simulating game conditions. Division I collegiate male ice hockey players (N = 8) wore Catapult Optimeye S5 monitors during repeat performance of 9 ice hockey tasks simulating game conditions. Ordered ice hockey tasks during repeated bouts included acceleration (forward or backward), 60% top-speed, top-speed (forward or backward), repeated shift circuit, ice coasting, slap shot, and bench sitting. Coefficient of variation (CV), intraclass correlation coefficient (ICC), and minimum difference (MD) were used to assess PlayerLoad reliability. Test-retest CVs and ICCs of PlayerLoad were as follows: 8.6% and 0.54 for forward acceleration, 13.8% and 0.78 for backward acceleration, 2.2% and 0.96 for 60% top-speed, 7.5% and 0.79 for forward top-speed, 2.8% and 0.96 for backward top-speed, 26.6% and 0.95 for repeated shift test, 3.9% and 0.68 for slap shot, 3.7% and 0.98 for coasting, and 4.1% and 0.98 for bench sitting, respectively. Raw differences between bouts were not significant for ice hockey tasks (p > 0.05). For each task, between-bout raw differences were lower vs. MD: 0.06 vs. 0.35 (forward acceleration), 0.07 vs. 0.36 (backward acceleration), 0.00 vs. 0.06 (60% top-speed), 0.03 vs. 0.20 (forward top-speed), 0.02 vs. 0.09 (backward top-speed), 0.18 vs. 0.64 (repeated shift test), 0.02 vs. 0.10 (slap shot), 0.00 vs. 0.10 (coasting), and 0.01 vs. 0.11 (bench sitting), respectively. These data suggest that PlayerLoad demonstrates moderate-to-large test-retest reliability in the environmental setting of male Division I collegiate ice hockey. Without previously testing reliability, these data are important as PlayerLoad is routinely quantified in male collegiate ice hockey to assess on ice physical activity.

Biomotor structures in elite female handball players.

PubMed

Katić, Ratko; Cavala, Marijana; Srhoj, Vatromir

2007-09-01

In order to identify biomotor structures in elite female handball players, factor structures of morphological characteristics and basic motor abilities of elite female handball players (N = 53) were determined first, followed by determination of relations between the morphological-motor space factors obtained and the set of criterion variables evaluating situation motor abilities in handball. Factor analysis of 14 morphological measures produced three morphological factors, i.e. factor of absolute voluminosity (mesoendomorph), factor of longitudinal skeleton dimensionality, and factor of transverse hand dimensionality. Factor analysis of 15 motor variables yielded five basic motor dimensions, i.e. factor of agility, factor of jumping explosive strength, factor of throwing explosive strength, factor of movement frequency rate, and factor of running explosive strength (sprint). Four significant canonic correlations, i.e. linear combinations, explained the correlation between the set of eight latent variables of the morphological and basic motor space and five variables of situation motoricity. First canonic linear combination is based on the positive effect of the factors of agility/coordination on the ability of fast movement without ball. Second linear combination is based on the effect of jumping explosive strength and transverse hand dimensionality on ball manipulation, throw precision, and speed of movement with ball. Third linear combination is based on the running explosive strength determination by the speed of movement with ball, whereas fourth combination is determined by throwing and jumping explosive strength, and agility on ball pass. The results obtained were consistent with the model of selection in female handball proposed (Srhoj et al., 2006), showing the speed of movement without ball and the ability of ball manipulation to be the predominant specific abilities, as indicated by the first and second linear combination.

Haptic perception accuracy depending on self-produced movement.

PubMed

Park, Chulwook; Kim, Seonjin

2014-01-01

This study measured whether self-produced movement influences haptic perception ability (experiment 1) as well as the factors associated with levels of influence (experiment 2) in racket sports. For experiment 1, the haptic perception accuracy levels of five male table tennis experts and five male novices were examined under two different conditions (no movement vs. movement). For experiment 2, the haptic afferent subsystems of five male table tennis experts and five male novices were investigated in only the self-produced movement-coupled condition. Inferential statistics (ANOVA, t-test) and custom-made devices (shock & vibration sensor, Qualisys Track Manager) of the data were used to determine the haptic perception accuracy (experiment 1, experiment 2) and its association with expertise. The results of this research show that expert-level players acquire higher accuracy with less variability (racket vibration and angle) than novice-level players, especially in their self-produced movement coupled performances. The important finding from this result is that, in terms of accuracy, the skill-associated differences were enlarged during self-produced movement. To explain the origin of this difference between experts and novices, the functional variability of haptic afferent subsystems can serve as a reference. These two factors (self-produced accuracy and the variability of haptic features) as investigated in this study would be useful criteria for educators in racket sports and suggest a broader hypothesis for further research into the effects of the haptic accuracy related to variability.

A review of vision-based motion analysis in sport.

PubMed

Barris, Sian; Button, Chris

2008-01-01

Efforts at player motion tracking have traditionally involved a range of data collection techniques from live observation to post-event video analysis where player movement patterns are manually recorded and categorized to determine performance effectiveness. Due to the considerable time required to manually collect and analyse such data, research has tended to focus only on small numbers of players within predefined playing areas. Whilst notational analysis is a convenient, practical and typically inexpensive technique, the validity and reliability of the process can vary depending on a number of factors, including how many observers are used, their experience, and the quality of their viewing perspective. Undoubtedly the application of automated tracking technology to team sports has been hampered because of inadequate video and computational facilities available at sports venues. However, the complex nature of movement inherent to many physical activities also represents a significant hurdle to overcome. Athletes tend to exhibit quick and agile movements, with many unpredictable changes in direction and also frequent collisions with other players. Each of these characteristics of player behaviour violate the assumptions of smooth movement on which computer tracking algorithms are typically based. Systems such as TRAKUS, SoccerMan, TRAKPERFORMANCE, Pfinder and Prozone all provide extrinsic feedback information to coaches and athletes. However, commercial tracking systems still require a fair amount of operator intervention to process the data after capture and are often limited by the restricted capture environments that can be used and the necessity for individuals to wear tracking devices. Whilst some online tracking systems alleviate the requirements of manual tracking, to our knowledge a completely automated system suitable for sports performance is not yet commercially available. Automatic motion tracking has been used successfully in other domains outside of elite sport performance, notably for surveillance in the military and security industry where automatic recognition of moving objects is achievable because identification of the objects is not necessary. The current challenge is to obtain appropriate video sequences that can robustly identify and label people over time, in a cluttered environment containing multiple interacting people. This problem is often compounded by the quality of video capture, the relative size and occlusion frequency of people, and also changes in illumination. Potential applications of an automated motion detection system are offered, such as: planning tactics and strategies; measuring team organisation; providing meaningful kinematic feedback; and objective measures of intervention effectiveness in team sports, which could benefit coaches, players, and sports scientists.

Design of a Virtual Player for Joint Improvisation with Humans in the Mirror Game

PubMed Central

Zhai, Chao; Alderisio, Francesco; Tsaneva-Atanasova, Krasimira; di Bernardo, Mario

2016-01-01

Joint improvisation is often observed among humans performing joint action tasks. Exploring the underlying cognitive and neural mechanisms behind the emergence of joint improvisation is an open research challenge. This paper investigates jointly improvised movements between two participants in the mirror game, a paradigmatic joint task example. First, experiments involving movement coordination of different dyads of human players are performed in order to build a human benchmark. No designation of leader and follower is given beforehand. We find that joint improvisation is characterized by the lack of a leader and high levels of movement synchronization. Then, a theoretical model is proposed to capture some features of their interaction, and a set of experiments is carried out to test and validate the model ability to reproduce the experimental observations. Furthermore, the model is used to drive a computer avatar able to successfully improvise joint motion with a human participant in real time. Finally, a convergence analysis of the proposed model is carried out to confirm its ability to reproduce joint movements between the participants. PMID:27123927

Design of a Virtual Player for Joint Improvisation with Humans in the Mirror Game.

PubMed

Zhai, Chao; Alderisio, Francesco; Słowiński, Piotr; Tsaneva-Atanasova, Krasimira; di Bernardo, Mario

2016-01-01

Joint improvisation is often observed among humans performing joint action tasks. Exploring the underlying cognitive and neural mechanisms behind the emergence of joint improvisation is an open research challenge. This paper investigates jointly improvised movements between two participants in the mirror game, a paradigmatic joint task example. First, experiments involving movement coordination of different dyads of human players are performed in order to build a human benchmark. No designation of leader and follower is given beforehand. We find that joint improvisation is characterized by the lack of a leader and high levels of movement synchronization. Then, a theoretical model is proposed to capture some features of their interaction, and a set of experiments is carried out to test and validate the model ability to reproduce the experimental observations. Furthermore, the model is used to drive a computer avatar able to successfully improvise joint motion with a human participant in real time. Finally, a convergence analysis of the proposed model is carried out to confirm its ability to reproduce joint movements between the participants.

Reducing musculoskeletal injury and concussion risk in schoolboy rugby players with a pre-activity movement control exercise programme: a cluster randomised controlled trial

PubMed Central

Hislop, Michael D; Stokes, Keith A; Williams, Sean; McKay, Carly D; England, Mike E; Kemp, Simon P T; Trewartha, Grant

2017-01-01

Background Injury risk in youth rugby has received much attention, highlighting the importance of establishing evidence-based injury reduction strategies. Aim To determine the efficacy of a movement control exercise programme in reducing injuries in youth rugby players and to investigate the effect of programme dose on injury measures. Methods In a cluster-randomised controlled trial, 40 independent schools (118 teams, 3188 players aged 14–18 years) were allocated to receive either the intervention or a reference programme, both of which were to be delivered by school coaches. The intervention comprised balance training, whole-body resistance training, plyometric training, and controlled rehearsal of landing and cutting manoeuvres. Time-loss (>24 hours) injuries arising from school rugby matches were recorded by coaches and medical staff. Results 441 time-loss match injuries (intervention, 233; control, 208) were reported across 15 938 match exposure-hours (intervention, 9083; control, 6855). Intention-to-treat results indicated unclear effects of trial arm on overall match injury incidence (rate ratio (RR)=0.85, 90% confidence limits 0.61 to 1.17), although clear reductions were evident in the intervention arm for concussion incidence (RR=0.71, 0.48 to 1.05). When trial arm comparisons were limited to teams who had completed three or more weekly programme sessions on average, clear reductions in overall match injury incidence (RR=0.28, 0.14 to 0.51) and concussion incidence (RR=0.41, 0.17 to 0.99) were noted in the intervention group. Conclusion A preventive movement control exercise programme can reduce match injury outcomes, including concussion, in schoolboy rugby players when compared with a standardised control exercise programme, although to realise the greatest effects players should complete the programme at least three times per week. PMID:28515056

Reducing musculoskeletal injury and concussion risk in schoolboy rugby players with a pre-activity movement control exercise programme: a cluster randomised controlled trial.

PubMed

Hislop, Michael D; Stokes, Keith A; Williams, Sean; McKay, Carly D; England, Mike E; Kemp, Simon P T; Trewartha, Grant

2017-08-01

Injury risk in youth rugby has received much attention, highlighting the importance of establishing evidence-based injury reduction strategies. To determine the efficacy of a movement control exercise programme in reducing injuries in youth rugby players and to investigate the effect of programme dose on injury measures. In a cluster-randomised controlled trial, 40 independent schools (118 teams, 3188 players aged 14-18 years) were allocated to receive either the intervention or a reference programme, both of which were to be delivered by school coaches. The intervention comprised balance training, whole-body resistance training, plyometric training, and controlled rehearsal of landing and cutting manoeuvres. Time-loss (>24 hours) injuries arising from school rugby matches were recorded by coaches and medical staff. 441 time-loss match injuries (intervention, 233; control, 208) were reported across 15 938 match exposure-hours (intervention, 9083; control, 6855). Intention-to-treat results indicated unclear effects of trial arm on overall match injury incidence (rate ratio (RR)=0.85, 90% confidence limits 0.61 to 1.17), although clear reductions were evident in the intervention arm for concussion incidence (RR=0.71, 0.48 to 1.05). When trial arm comparisons were limited to teams who had completed three or more weekly programme sessions on average, clear reductions in overall match injury incidence (RR=0.28, 0.14 to 0.51) and concussion incidence (RR=0.41, 0.17 to 0.99) were noted in the intervention group. A preventive movement control exercise programme can reduce match injury outcomes, including concussion, in schoolboy rugby players when compared with a standardised control exercise programme, although to realise the greatest effects players should complete the programme at least three times per week. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Physiological and psychophysiological responses to an exer-game training protocol.

PubMed

Bronner, Shaw; Pinsker, Russell; Naik, Rutika; Noah, J Adam

2016-03-01

Exer-games and virtual reality offer alternative opportunities to provide neuro-rehabilitation and exercise that are fun. Our goal was to determine how effective they are in achieving motor learning goals and fitness benefits as players gain experience. We employed a repeated measures design to determine changes in physical exertion and engagement with training. Fourteen healthy adults trained on the XBOX Kinect video game Dance Central using a skill-based protocol to examine changes in energy expenditure (EE), heart rate (HR), METs, limb movement, game proficiency, and player engagement in initial, post-training, and transfer-testing of a full-body dance exer-game. Data were analyzed using repeated measures analysis of variance, p<0.05. Both EE, HR, and METs increased from initial (EE 4.89±1.35, HR 103±18, METs 4.25±0.72) to post-training (EE 5.92±1.25, HR 110±15, METs 5.05±0.75) and were greatest during transfer-testing (EE 6.34±1.35, HR 115±17, METs 5.42±0.88, p≤0.001). Proficiency, measured by game scores, also increased from initial to post-training and transfer-testing (p≤0.002). Limb movement and player engagement remained unchanged. It is important to understand whether player physiological and psychophysiological responses change with continued game-play. Although Dance Central involves whole-body movement, physical exertion remained at moderate levels after training. As exer-game and virtual reality systems move from their initial novelty, research about how players react to continued involvement with a game can guide game developers to maintain a freshness through game progression that preserves the participant's attentional focus, minimizes attrition and maintains a prescribed level of energy exertion. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

The physical demands of Super 14 rugby union.

PubMed

Austin, Damien; Gabbett, Tim; Jenkins, David

2011-05-01

The purpose of the present study was to describe the match-play demands of professional rugby union players competing in Super 14 matches during the 2008 and 2009 seasons. The movements of 20 players from Super 14 rugby union team during the 2008 and 2009 seasons were video recorded. Using time-motion analysis (TMA), five players from four positional groups (front-row forwards, back-row forwards, inside backs and outside backs) were assessed. Players covered between 4218 m and 6389 m during the games. The maximum distances covered in a game by the four groups were: front row forwards (5139 m), back row forwards, (5422 m), inside backs (6389 m) and outside backs (5489 m). The back row forwards spent the greatest amount of time in high-intensity exercise (1190 s), followed by the front row forwards (1015 s), the inside backs (876 s) and the outside backs (570 s). Average distances covered in individual sprint efforts were: front row forwards (16 m), back row forwards (14 m), inside backs (17 m) and outside backs (18 m). Work to rest ratios of 1:4, 1:4, 1:5, and 1:6 were found for the front row and back row forwards, and inside and outside backs respectively. The Super 14 competition during 2008 and 2009, have resulted in an increase in total high-intensity activities, sprint frequency, and work to rest ratios across all playing positions. For players and teams to remain competitive in Super 14 rugby, training (including recovery practices) should reflect these current demands. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Basketball Teams as Strategic Networks

PubMed Central

Fewell, Jennifer H.; Armbruster, Dieter; Ingraham, John; Petersen, Alexander; Waters, James S.

2012-01-01

We asked how team dynamics can be captured in relation to function by considering games in the first round of the NBA 2010 play-offs as networks. Defining players as nodes and ball movements as links, we analyzed the network properties of degree centrality, clustering, entropy and flow centrality across teams and positions, to characterize the game from a network perspective and to determine whether we can assess differences in team offensive strategy by their network properties. The compiled network structure across teams reflected a fundamental attribute of basketball strategy. They primarily showed a centralized ball distribution pattern with the point guard in a leadership role. However, individual play-off teams showed variation in their relative involvement of other players/positions in ball distribution, reflected quantitatively by differences in clustering and degree centrality. We also characterized two potential alternate offensive strategies by associated variation in network structure: (1) whether teams consistently moved the ball towards their shooting specialists, measured as “uphill/downhill” flux, and (2) whether they distributed the ball in a way that reduced predictability, measured as team entropy. These network metrics quantified different aspects of team strategy, with no single metric wholly predictive of success. However, in the context of the 2010 play-offs, the values of clustering (connectedness across players) and network entropy (unpredictability of ball movement) had the most consistent association with team advancement. Our analyses demonstrate the utility of network approaches in quantifying team strategy and show that testable hypotheses can be evaluated using this approach. These analyses also highlight the richness of basketball networks as a dataset for exploring the relationships between network structure and dynamics with team organization and effectiveness. PMID:23139744

Basketball teams as strategic networks.

PubMed

Fewell, Jennifer H; Armbruster, Dieter; Ingraham, John; Petersen, Alexander; Waters, James S

2012-01-01

We asked how team dynamics can be captured in relation to function by considering games in the first round of the NBA 2010 play-offs as networks. Defining players as nodes and ball movements as links, we analyzed the network properties of degree centrality, clustering, entropy and flow centrality across teams and positions, to characterize the game from a network perspective and to determine whether we can assess differences in team offensive strategy by their network properties. The compiled network structure across teams reflected a fundamental attribute of basketball strategy. They primarily showed a centralized ball distribution pattern with the point guard in a leadership role. However, individual play-off teams showed variation in their relative involvement of other players/positions in ball distribution, reflected quantitatively by differences in clustering and degree centrality. We also characterized two potential alternate offensive strategies by associated variation in network structure: (1) whether teams consistently moved the ball towards their shooting specialists, measured as "uphill/downhill" flux, and (2) whether they distributed the ball in a way that reduced predictability, measured as team entropy. These network metrics quantified different aspects of team strategy, with no single metric wholly predictive of success. However, in the context of the 2010 play-offs, the values of clustering (connectedness across players) and network entropy (unpredictability of ball movement) had the most consistent association with team advancement. Our analyses demonstrate the utility of network approaches in quantifying team strategy and show that testable hypotheses can be evaluated using this approach. These analyses also highlight the richness of basketball networks as a dataset for exploring the relationships between network structure and dynamics with team organization and effectiveness.

CUE USAGE IN VOLLEYBALL: A TIME COURSE COMPARISON OF ELITE, INTERMEDIATE AND NOVICE FEMALE PLAYERS

PubMed Central

Vaeyens, R; Zeuwts, L; Philippaerts, R; Lenoir, M

2014-01-01

This study compared visual search strategies in adult female volleyball players of three levels. Video clips of the attack of the opponent team were presented on a large screen and participants reacted to the final pass before the spike. Reaction time, response accuracy and eye movement patterns were measured. Elite players had the highest response accuracy (97.50 ± 3.5%) compared to the intermediate (91.50 ± 4.7%) and novice players (83.50 ± 17.6%; p<0.05). Novices had a remarkably high range of reaction time but no significant differences were found in comparison to the reaction time of elite and intermediate players. In general, the three groups showed similar gaze behaviour with the apparent use of visual pivots at moments of reception and final pass. This confirms the holistic model of image perception for volleyball and suggests that expert players extract more information from parafoveal regions. PMID:25609887

Efficiently detecting outlying behavior in video-game players

PubMed Central

Kim, Young Bin; Kang, Shin Jin; Lee, Sang Hyeok; Jung, Jang Young; Kam, Hyeong Ryeol; Lee, Jung; Kim, Young Sun; Lee, Joonsoo

2015-01-01

In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players’ characteristics. These characteristics are captured non-invasively in a general game environment. In this paper, cameras were used to analyze observed data such as facial expressions and player movements. Moreover, multimodal data from the game players (i.e., data regarding adjustments to the volume and the use of the keyboard and mouse) was used to analyze high-dimensional game-player data. A support vector machine was used to efficiently detect outlying behaviors. We verified the effectiveness of the proposed method using games from several genres. The recall rate of the outlying behavior pre-identified by industry experts was approximately 70%. The proposed method can also be used for feedback analysis of various interactive content provided in PC environments. PMID:26713250

Position-Dependent Cardiovascular Response and Time-Motion Analysis During Training Drills and Friendly Matches in Elite Male Basketball Players.

PubMed

Torres-Ronda, Lorena; Ric, Angel; Llabres-Torres, Ivan; de Las Heras, Bernat; Schelling I Del Alcazar, Xavi

2016-01-01

The purpose of this study was to measure differences in the cardiovascular workload (heart rate [HR]) and time-motion demands between positional groups, during numerous basketball training drills, and compare the results with in-game competition demands. A convenience sample of 14 top-level professional basketball players from the same club (Spanish First Division, ACB) participated in the study. A total of 146 basketball exercises per player (performed over an 8-week period in 32 team training sessions throughout the competitive season) and 7 friendly matches (FM) played during the preparatory phase were analyzed. The results reveal that HRavg and HRpeak were the highest in FM (158 ± 10; 198 ± 9 b · min(-1), respectively). Time-motion analysis showed 1v1 to be the most demanding drill (53 ± 8 and 46 ± 12 movements per minute for full and half court, respectively). During FM, players performed 33 ± 7 movements per minute. Positional differences exist for both HR and time-motion demands, ranging from moderate to very large for all basketball drills compared with FM. Constraints such as number of players, court size, work-to-rest ratios, and coach intervention are key factors influencing cardiovascular responses and time-motion demands during basketball training sessions. These results demonstrate that systematic monitoring of the physical demands and physiological responses during training and competition can inform and potentially improve coaching strategy, basketball-specific training drills, and ultimately, match performance.

Physiological, movement and technical demands of centre-wicket Battlezone, traditional net-based training and one-day cricket matches: a comparative study of sub-elite cricket players.

PubMed

Vickery, Will; Dascombe, Ben; Duffield, Rob

2014-01-01

This study compared physiological, physical and technical demands of Battlezone, traditional cricket training and one-day matches. Data were initially collected from 11 amateur, male cricket players (age: 22.2 ± 3.3 year, height: 1.82 ± 0.06 m body mass: 80.4 ± 9.8 kg) during four Battlezone and four traditional cricket training sessions encompassing different playing positions. Heart rate, blood lactate concentration, rating of perceived exertion and movement patterns of players were measured. Retrospective video analysis was performed to code for technical outcomes. Similar data were collected from 42 amateur, male cricket players (23.5 ± 4.7 year, 1.81 ± 0.07 m, 81.4 ± 11.4 kg) during one-day matches. Significant differences were found between Battlezone, traditional cricket training and one-day matches within each playing position. Specifically, Battlezone invoked the greatest physiological and physical demands from batsmen in comparison to traditional cricket training and one-day matches. However, the greatest technical demand for batsmen was observed during traditional cricket training. In regards to the other playing positions, a greater physiological, physical and technical demand was observed during Battlezone and traditional training than during one-day matches. These results suggest that the use of Battlezone and traditional cricket training provides players with a suitable training stimulus for replicating the physiological, physical and technical demands of one-day cricket.

Activity profiles of the Australian female netball team players during international competition: implications for training practice.

PubMed

Fox, Aaron; Spittle, Michael; Otago, Leonie; Saunders, Natalie

2013-01-01

In elite sport, to remain competitive at the international level, it is critical to understand the game demands on players to ensure sport specific training programmes are designed for optimal athlete preparation and conditioning. In netball, recent research examining the activity patterns of players at the elite level is lacking, with only one study undertaken on this level of competition in the past 30 years. Therefore, the aim of this study was to provide coaches with up to date knowledge of player activity patterns as a basis for the design of optimal sport specific training programmes. The Australian female netball team were analysed using video footage of three international test matches. Player activity was categorised into five movement and eight game-based activities; and further classified as work or rest. Results suggest that differences in the current game exist when compared to the previous analysis. Positional differences were also found with regard to player activity confirming the need for an individualised component of training based on player position.

The Effect of Biological Movement Variability on the Performance of the Golf Swing in High- and Low-Handicapped Players

ERIC Educational Resources Information Center

Bradshaw, Elizabeth J.; Keogh, Justin W. L.; Hume, Patria A.; Maulder, Peter S.; Nortje, Jacques; Marnewick, Michel

2009-01-01

The purpose of this study was to examine the role of neuromotor noise on golf swing performance in high- and low-handicap players. Selected two-dimensional kinematic measures of 20 male golfers (n = 10 per high- or low-handicap group) performing 10 golf swings with a 5-iron club was obtained through video analysis. Neuromotor noise was calculated…

Somatotype-variables related to muscle torque and power output in female volleyball players.

PubMed

Buśko, Krzysztof; Lewandowska, Joanna; Lipińska, Monika; Michalski, Radosław; Pastuszak, Anna

2013-01-01

The purpose of this study was to investigate the relationship between somatotype, muscle torque, maximal power output and height of rise of the body mass centre measured in akimbo counter movement jump (ACMJ), counter movement jump (CMJ) and spike jump (SPJ), and power output measured in maximal cycle ergometer exercise bouts in female volleyball players. Fourteen players participated in the study. Somatotype was determined using the Heath-Carter method. Maximal muscle torque was measured under static conditions. Power output was measured in 5 maximal cycle ergometer exercise bouts, 10 s each, at increasing external loads equal to 2.5, 5.0, 7.5, 10.0 and 12.5% of body weight (BW). All jump trials (ACMJ, SPJ and CMJ) were performed on a force plate. The mean somatotype of volleyball players was: 4.9-3.5-2.5. The value of the sum of muscle torque of the left upper extremities was significantly correlated only with mesomorphic component. Mesomorphic and ectomorphic components correlated significantly with values of maximal power measured during ACMJ and CMJ. Power output measured in maximal cycle ergometer exercise bouts at increasing external loads equal to 2.5, 5.0 and 7.5% of BW was significantly correlated with endomorphy, mesomorphy and ectomorphy.

Neuromuscular Risk Factors for Knee and Ankle Ligament Injuries in Male Youth Soccer Players

PubMed Central

Read, Paul J.; Oliver, Jon L.; De Ste Croix, Mark B. A.; Myer, Gregory D.; Lloyd, Rhodri S.

2017-01-01

Injuries reported in male youth soccer players most commonly occur in the lower extremities, and include a high proportion of ligament sprains at the ankle and knee with a lower proportion of overuse injuries. There is currently a paucity of available literature that examines age- and sex-specific injury risk factors for such injuries within youth soccer players. Epidemiological data have reported movements that lead to non-contact ligament injury include running, twisting and turning, over-reaching and landing. Altered neuromuscular control during these actions has been suggested as a key mechanism in females and adult populations; however, data available in male soccer players is sparse. The focus of this article is to review the available literature and elucidate prevalent risk factors pertaining to male youth soccer players which may contribute to their relative risk of injury. PMID:26856339

Tracking of Ball and Players in Beach Volleyball Videos

PubMed Central

Gomez, Gabriel; Herrera López, Patricia; Link, Daniel; Eskofier, Bjoern

2014-01-01

This paper presents methods for the determination of players' positions and contact time points by tracking the players and the ball in beach volleyball videos. Two player tracking methods are compared, a classical particle filter and a rigid grid integral histogram tracker. Due to mutual occlusion of the players and the camera perspective, results are best for the front players, with 74,6% and 82,6% of correctly tracked frames for the particle method and the integral histogram method, respectively. Results suggest an improved robustness against player confusion between different particle sets when tracking with a rigid grid approach. Faster processing and less player confusions make this method superior to the classical particle filter. Two different ball tracking methods are used that detect ball candidates from movement difference images using a background subtraction algorithm. Ball trajectories are estimated and interpolated from parabolic flight equations. The tracking accuracy of the ball is 54,2% for the trajectory growth method and 42,1% for the Hough line detection method. Tracking results of over 90% from the literature could not be confirmed. Ball contact frames were estimated from parabolic trajectory intersection, resulting in 48,9% of correctly estimated ball contact points. PMID:25426936

Charter School Authorizing: Are States Making the Grade?

ERIC Educational Resources Information Center

Palmer, Louann Bierlein; Gau, Rebecca

2003-01-01

When the charter school movement began in the early 1990's, one key set of players received little attention: the public entities that sponsor or authorize these unconventional schools. A charter is properly understood as a contract between two parties, the school operator and the authorizer. For the charter movement to succeed, both must do their…

The importance of open- and closed-skill agility for team selection of adult male basketball players.

PubMed

Scanlan, A T; Tucker, P S; Dalbo, V J

2015-05-01

Open-skill agility qualities have yet to be described in adult male basketball players. Further, the importance of open- and closed-skill agility for team selection remains unknown. Thus, this study aimed to: 1) describe the open- and closed-skill agility of adult male basketball players; and 2) compare these properties between starting and non-starting players. A cross-sectional between-group design was used. Six starting (playing time: 30.1 ± 8.8 min; age: 30.5 ± 4.8 years; height: 192.1 ± 7.7 cm; body mass: 100.5 ± 15.0 kg; VO(2max): 48.4 ± 6.6 mL∙kg⁻¹∙min⁻¹) and six non-starting (4.3 ± 3.6 min; 21.3 ± 5 years; 185.7 ± 7.4 cm; 94.4 ± 17.9 kg; 50.6 ± 3.9 mL∙kg⁻¹∙min⁻¹) state-level basketball players completed multiple trials for the Change of Direction Speed Test (CODST) and Reactive Agility Test (RAT). No statistically significant between-group differences were evident for CODST movement time (starters: 1.652 ± 0.047 s; non-starters: 1.626 ± 0.040 s, P=0.68), RAT response time (starters: 307.5 ± 100.5 ms; non-starters: 426.5 ± 140.7 ms, P=0.12), and RAT decision-making time (starters: 110.7 ± 11.0 ms; non-starters: 147.3 ± 14.2 ms, P=0.08). However, starters (2.001 ± 0.051 s) possessed significantly (P=0.02) faster RAT total movement times than non-starters (2.182 ± 0.040 s). These data support the utility of perceptual and cognitive components of agility performance in distinguishing starting from non-starting players in basketball. Consequently, basketball coaching and conditioning staff should incorporate sport-specific reactive training drills for all players during the annual conditioning plan.

Physiologically Modulating Videogames or Simulations which Use Motion-Sensing Input Devices

NASA Technical Reports Server (NTRS)

Blanson, Nina Marie (Inventor); Stephens, Chad L. (Inventor); Pope, Alan T. (Inventor)

2017-01-01

New types of controllers allow a player to make inputs to a video game or simulation by moving the entire controller itself or by gesturing or by moving the player's body in whole or in part. This capability is typically accomplished using a wireless input device having accelerometers, gyroscopes, and a camera. The present invention exploits these wireless motion-sensing technologies to modulate the player's movement inputs to the videogame based upon physiological signals. Such biofeedback-modulated video games train valuable mental skills beyond eye-hand coordination. These psychophysiological training technologies enhance personal improvement, not just the diversion, of the user.

Functional Movements in Japanese Mini-Basketball Players

PubMed Central

Kuzuhara, Kenji; Shibata, Masashi; Iguchi, Junta; Uchida, Ryo

2018-01-01

Abstract Functional movement screen (FMS) has been used to establish normative data and determine potential injury risk for young adults and athletes, but there are few data in elementary school-age children. The purpose of this study was to establish fundamental values for the FMS in elementary school-age mini-basketball players. Secondary purposes were to examine relationships between functional movement patterns and age, peak height velocity (PHV), and body mass index (BMI), and to compare functional movement patterns between boys and girls and between individuals with and without a history of injury. The mean composite FMS score was 16.5 ± 2.2 (16.5 ± 2.4 for boys, 16.5 ± 1.7 for girls). The composite FMS score was positively correlated with age (r = .312) and negatively correlated with the BMI (r = − .371). However, the FMS score was not correlated with PHV or with PHV age. The FMS score was not different between boys and girls or between individuals who reported a previous injury and those who did not. However, boys in the mini-basketball teams performed better than girls on the trunk stability push-up and rotary stability tests. Age and the body mass index were significantly associated with better and poorer functional movement, respectively. PMID:29599859

Functional Movements in Japanese Mini-Basketball Players.

PubMed

Kuzuhara, Kenji; Shibata, Masashi; Iguchi, Junta; Uchida, Ryo

2018-03-01

Functional movement screen (FMS) has been used to establish normative data and determine potential injury risk for young adults and athletes, but there are few data in elementary school-age children. The purpose of this study was to establish fundamental values for the FMS in elementary school-age mini-basketball players. Secondary purposes were to examine relationships between functional movement patterns and age, peak height velocity (PHV), and body mass index (BMI), and to compare functional movement patterns between boys and girls and between individuals with and without a history of injury. The mean composite FMS score was 16.5 ± 2.2 (16.5 ± 2.4 for boys, 16.5 ± 1.7 for girls). The composite FMS score was positively correlated with age (r = .312) and negatively correlated with the BMI (r = - .371). However, the FMS score was not correlated with PHV or with PHV age. The FMS score was not different between boys and girls or between individuals who reported a previous injury and those who did not. However, boys in the mini-basketball teams performed better than girls on the trunk stability push-up and rotary stability tests. Age and the body mass index were significantly associated with better and poorer functional movement, respectively.

A Novel Computer-Based Set-Up to Study Movement Coordination in Human Ensembles

PubMed Central

Alderisio, Francesco; Lombardi, Maria; Fiore, Gianfranco; di Bernardo, Mario

2017-01-01

Existing experimental works on movement coordination in human ensembles mostly investigate situations where each subject is connected to all the others through direct visual and auditory coupling, so that unavoidable social interaction affects their coordination level. Here, we present a novel computer-based set-up to study movement coordination in human groups so as to minimize the influence of social interaction among participants and implement different visual pairings between them. In so doing, players can only take into consideration the motion of a designated subset of the others. This allows the evaluation of the exclusive effects on coordination of the structure of interconnections among the players in the group and their own dynamics. In addition, our set-up enables the deployment of virtual computer players to investigate dyadic interaction between a human and a virtual agent, as well as group synchronization in mixed teams of human and virtual agents. We show how this novel set-up can be employed to study coordination both in dyads and in groups over different structures of interconnections, in the presence as well as in the absence of virtual agents acting as followers or leaders. Finally, in order to illustrate the capabilities of the architecture, we describe some preliminary results. The platform is available to any researcher who wishes to unfold the mechanisms underlying group synchronization in human ensembles and shed light on its socio-psychological aspects. PMID:28649217

Physical and Physiological Demands of Experienced Male Basketball Players During a Competitive Game.

PubMed

Puente, Carlos; Abián-Vicén, Javier; Areces, Francisco; López, Roberto; Del Coso, Juan

2017-04-01

Puente, C, Abián-Vicén, J, Areces, F, López, R, and Del Coso, J. Physical and physiological demands of experienced male basketball players during a competitive game. J Strength Cond Res 31(4): 956-962, 2017-The aim of this investigation was to analyze the physical and physiological demands of experienced basketball players during a real and competitive game. Twenty-five well-trained basketball players (8 guards, 8 forwards, and 9 centers) played a competitive game on an outdoor court. Instantaneous running speeds, the number of body impacts above 5 g, and the number of accelerations and decelerations were assessed by means of a 15-Hz global Positioning System accelerometer unit. Individual heart rate was also recorded using heart rate monitors. As a group mean, the basketball players covered 82.6 ± 7.8 m·min during the game with a mean heart rate of 89.8 ± 4.4% of maximal heart rate. Players covered 3 ± 3% of the total distance running at above 18 km·h and performed 0.17 ± 0.13 sprints per minute. The number of body impacts was 8.2 ± 1.8 per minute of play. The running pace of forwards was higher than that of centers (86.8 ± 6.2 vs. 76.6 ± 6.0 m·min; p ≤ 0.05). The maximal speed obtained during the game was significantly higher for guards than that for centers (24.0 ± 1.6 km·h vs. 21.3 ± 1.6 km·h; p ≤ 0.05). Centers performed a lower number of accelerations/decelerations than guards and forwards (p ≤ 0.05). In conclusion, the extraordinary rates of specific movements performed by these experienced basketball players indicate the high physiological demands necessary to be able to compete in this sport. The centers were the basketball players who showed lower physiological demands during a game, whereas there were no differences between guards and forwards. These results can be used by coaches to adapt basketball training programs to the specific demands of each playing position.

Gender-specific activity demands experienced during semiprofessional basketball game play.

PubMed

Scanlan, Aaron T; Dascombe, Ben J; Kidcaff, Andrew P; Peucker, Jessica L; Dalbo, Vincent J

2015-07-01

To compare game activity demands between female and male semiprofessional basketball players. Female (n=12) and male (n=12) semiprofessional basketball players were monitored across 3 competitive games. Time-motion-analysis procedures quantified player activity into predefined movement categories across backcourt (BC) and frontcourt (FC) positions. Activity frequencies, durations, and distances were calculated relative to live playing time (min). Work:rest ratios were also calculated using the video data. Game activity was compared between genders for each playing position and all players. Female players performed at greater running work-rates than male players (45.7±1.4 vs. 42.1±1.7 m/min, P=.05), while male players performed more dribbling than female players (2.5±0.3 vs. 3.0±0.2 s/min; 8.4±0.3 vs. 9.7±0.7 m/min, P=.05). Positional analyses revealed that female BC players performed more low-intensity shuffling (P=.04) and jumping (P=.05), as well as longer (P=.04) jogging durations, than male BC players. Female FC players executed more upper-body activity (P=.03) and larger work:rest ratios (P<.001) than male FC players. No significant gender differences were observed in the overall intermittent demands, distance traveled, high-intensity shuffling activity, and sprinting requirements during game play. These findings indicate that gender-specific running and dribbling differences might exist in semiprofessional basketball. Furthermore, position-specific variations between female and male basketball players should be considered. These data may prove useful in the development of gender-specific conditioning plans relative to playing position in basketball.

Effect of an Arm Swing on Countermovement Vertical Jump Performance in Elite Volleyball Players: FINAL.

PubMed

Vaverka, Frantisek; Jandačka, Daniel; Zahradník, David; Uchytil, Jaroslav; Farana, Roman; Supej, Matej; Vodičar, Janez

2016-12-01

The aim of this study was to determine how elite volleyball players employed the arm swing (AS) to enhance their jump performance. The study assessed how the AS influenced the duration and magnitude of the vertical ground reaction force (VGRF) during the main phases (preparatory, braking and accelerating) of the countermovement vertical jump (CMVJ), the starting position of the body at the beginning of the accelerating phase and the moment when the AS began contributing to increasing the jump height. Eighteen elite volleyball players performed three CMVJs with and without an AS. Kinetics and kinematics data were collected using two Kistler force plates and the C-motion system. The time and force variables were evaluated based on the VGRF, and the position of the body and the trajectory of the arm movement were determined using kinematic analysis. The AS improved the CMVJ by increasing the jump height by 38% relative to jumping without an AS. The AS significantly shortened the braking phase and prolonged the accelerating phase, however, it did not influence the preparatory phase or the overall jump duration. The AS also significantly increased the average force during the accelerating phase as well as the accelerating impulse. The AS upward began at 76% into the overall jump duration. The AS did not influence the body position at the beginning of the accelerating phase. These findings can be used to improve performance of the CMVJ with the AS and in teaching beginning volleyball players proper jumping technique.

Acute fatigue impairs neuromuscular activity of anterior cruciate ligament-agonist muscles in female team handball players.

PubMed

Zebis, M K; Bencke, J; Andersen, L L; Alkjaer, T; Suetta, C; Mortensen, P; Kjaer, M; Aagaard, P

2011-12-01

In sports, like team handball, fatigue has been associated with an increased risk of anterior cruciate ligament (ACL) injury. While effects of fatigue on muscle function are commonly assessed during maximal isometric voluntary contraction (MVC), such measurements may not relate to the muscle function during match play. The purpose of this study was to investigate the effect of muscle fatigue induced by a simulated handball match on neuromuscular strategy during a functional sidecutting movement, associated with the incidence of ACL injury. Fourteen female team handball players were tested for neuromuscular activity [electromyography (EMG)] during a sidecutting maneuver on a force plate, pre and post a simulated handball match. MVC was obtained during maximal isometric quadriceps and hamstring contraction. The simulated handball match consisted of exercises mimicking handball match activity. Whereas the simulated handball match induced a decrease in MVC strength for both the quadriceps and hamstring muscles (P<0.05), a selective decrease in hamstring neuromuscular activity was seen during sidecutting (P<0.05). This study shows impaired ACL-agonist muscle (i.e. hamstring) activity during sidecutting in response to acute fatigue induced by handball match play. Thus, screening procedures should involve functional movements to reveal specific fatigue-induced deficits in ACL-agonist muscle activation during high-risk phases of match play. © 2010 John Wiley & Sons A/S.

Differences in Neuromuscular Strategies Between Landing and Cutting Tasks in Female Basketball and Soccer Athletes

PubMed Central

Cowley, Hanni R; Ford, Kevin R; Myer, Gregory D; Kernozek, Thomas W; Hewett, Timothy E

2006-01-01

Context: High school female athletes are most likely to sustain a serious knee injury during soccer or basketball, 2 sports that often involve a rapid deceleration before a change of direction or while landing from a jump. Objective: To determine if female high school basketball and soccer players show neuromuscular differences during landing and cutting tasks and to examine neuromuscular differences between tasks and between dominant and nondominant sides. Design: A 3-way mixed factorial design investigating the effects of sport (basketball, soccer), task (jumping, cutting), and side (dominant, nondominant). Setting: Laboratory. Patients or Other Participants: Thirty high school female athletes who listed either basketball or soccer as their only sport of participation (basketball: n = 15, age = 15.1 ± 1.7 years, experience = 6.9 ± 2.2 years, height = 165.3 ± 7.9 cm, mass = 61.8 ± 9.3 kg; soccer: n = 15, age = 14.8 ± 0.8 years, experience = 8.8 ± 2.5 years, height = 161.8 ± 4.1 cm, mass = 54.6 ± 7.6 kg). Main Outcome Measure(s): Ground reaction forces, stance time, valgus angles, and valgus moments were assessed during (1) a drop vertical jump with an immediate maximal vertical jump and (2) an immediate side-step cut at a 45° angle. Results: Basketball athletes had greater ground reaction forces (P < .001) and decreased stance time (P < .001) during the drop vertical jump, whereas soccer players had greater ground reaction forces (P <.001) and decreased stance time (P < .001) during the cut. Subjects in both sports had greater valgus angles (initial contact and maximum, P = .02 and P = .012, respectively) during cutting than during the drop vertical jump. Greater valgus moments (P = .006) were noted on the dominant side during cutting. Conclusions: Our subjects demonstrated differences in ground reaction forces and stance times during 2 movements associated with noncontact anterior cruciate ligament injuries. Knee valgus moment and angle were significantly influenced by the type of movement performed. Sport-specific neuromuscular training may be warranted, with basketball players focusing on jumping and landing and soccer players focusing on unanticipated cutting maneuvers. PMID:16619097

Evaluation of Seasonal Changes in Fitness, Anthropometrics, and Body Composition in Collegiate Division Ii Female Soccer Players.

PubMed

Peart, Ashley N; Nicks, Clayton R; Mangum, Michael; Tyo, Brian M

2018-03-22

The purpose of this study was to investigate anthropometrics, body composition, aerobic and anaerobic fitness of collegiate Division II female soccer players throughout a calendar year. Eighteen (20 ± 0.9y) NCAA division II female soccer players from the same team participated in the study. Anthropometrics and body composition variables were assessed in addition to the Counter Movement Jump (CMJ), Wingate Anaerobic Test (WAT), and peak oxygen uptake (VO2peak). Data were collected over five time points: end of competitive seasons (ECS1 and ECS2), beginning of off-season (BOS), end of off-season (EOS), and pre-season (PS). Repeated-measures analysis of variance (ANOVA) were conducted to compare test scores among all five data collection points. Where appropriate, Bonferroni post-hoc tests were used to determine which points were significantly different. Hip circumference (HC) decreased significantly (p < 0.001) from EOS (98.47 ± 6.5 cm) to PS (94.46 ± 6.8 cm). Fat mass (FM) (12.73 ± 5.4 kg) was significantly different in ECS2 compared to BOS and EOS means (p ≤ 0.05) and percentage of body fat (%BF) (20.08 ± 5.44) significantly different in ECS2 compared to ECS1, BOS, and EOS means (p ≤ 0.05), while fat-free mass (FFM) was maintained from ECS1 to ECS2. CMJ, WAT, and VO2peak performance did not significantly change from ECS1 to ECS2. Anthropometrics and body composition results are similar to previous studies measuring Division II to professional female soccer players. CMJ results remained consistent and are comparable to results on Division I female soccer players. Coaches and researchers can use these data to help design and evaluate training programs throughout a calendar year.

Dynamic balance ability in young elite soccer players: implication of isometric strength.

PubMed

Chtara, Moktar; Rouissi, Mehdi; Bragazzi, Nicola L; Owen, Adam L; Haddad, Monoem; Chamari, Karim

2018-04-01

Soccer requires maintaining unilateral balance when executing movement with the contralateral leg. Despite the fact that balance requires standing with maintaining isometric posture with the support leg, currently there is a lack of studies regarding the implication of isometric strength on dynamic balance's performance among young soccer players. Therefore, the aim of this study was to examine the relationship between the Y-Balance Test and 12 lower limbs isometric strength tests. Twenty-six right footed soccer players (mean±SD, age=16.2±1.6 years, height=175±4.2 cm, body mass=68.8±6.1 kg) performed a dynamic balance test (star excursion balance-test with dominant- (DL) and nondominant-legs (NDL). Furthermore, maximal isometric contraction tests of 12 lower limb muscle groups were assessed in DL and NDL. Correlations analysis reported a significant positive relationship between some of isometric strength tests (with DL and NDL) and the Y-Balance Test. Furthermore, stepwise multiple regression analysis showed that maximal isometric strength explained between 21.9% and 49.4% of the variance of the Y-Balance Test. Moreover, maximal isometric strength was dependent upon the reaching angle of the Y-Balance Test and the leg used to support body weight. This study showed a significant implication of maximal isometric strength of the lower limb and the Y-Balance Test. Moreover, the present investigation suggests the implementation of specific lower limb strengthening exercises depending on players' deficit in each reaching direction and leg. This result suggests that further studies should experiment if increasing lower limbs isometric strength could improve dynamic balance ability among young soccer players.

Practice effects on intra-team synergies in football teams.

PubMed

Silva, Pedro; Chung, Dante; Carvalho, Thiago; Cardoso, Tiago; Davids, Keith; Araújo, Duarte; Garganta, Júlio

2016-04-01

Developing synchronised player movements for fluent competitive match play is a common goal for coaches of team games. An ecological dynamics approach advocates that intra-team synchronization is governed by locally created information, which specifies shared affordances responsible for synergy formation. To verify this claim we evaluated coordination tendencies in two newly-formed teams of recreational players during association football practice games, weekly, for fifteen weeks (thirteen matches). We investigated practice effects on two central features of synergies in sports teams - dimensional compression and reciprocal compensation here captured through near in-phase modes of coordination and time delays between coupled players during forward and backwards movements on field while attacking and defending. Results verified that synergies were formed and dissolved rapidly as a result of the dynamic creation of informational properties, perceived as shared affordances among performers. Practising once a week led to small improvements in the readjustment delays between co-positioning team members, enabling faster regulation of coordinated team actions. Mean values of the number of player and team synergies displayed only limited improvements, possibly due to the timescales of practice. No relationship between improvements in dimensional compression and reciprocal compensation were found for number of shots, amount of ball possession and number of ball recoveries made. Findings open up new perspectives for monitoring team coordination processes in sport. Copyright © 2015 Elsevier B.V. All rights reserved.

The geometry of expertise

PubMed Central

Leone, María J.; Fernandez Slezak, Diego; Cecchi, Guillermo A.; Sigman, Mariano

2014-01-01

Theories of expertise based on the acquisition of chunk and templates suggest a differential geometric organization of perception between experts and novices. It is implied that expert representation is less anchored by spatial (Euclidean) proximity and may instead be dictated by the intrinsic relation in the structure and grammar of the specific domain of expertise. Here we set out to examine this hypothesis. We used the domain of chess which has been widely used as a tool to study human expertise. We reasoned that the movement of an opponent piece to a specific square constitutes an external cue and the reaction of the player to this “perturbation” should reveal his internal representation of proximity. We hypothesized that novice players will tend to respond by moving a piece in closer squares than experts. Similarly, but now in terms of object representations, we hypothesized weak players will more likely focus on a specific piece and hence produce sequence of actions repeating movements of the same piece. We capitalized on a large corpus of data obtained from internet chess servers. Results showed that, relative to experts, weaker players tend to (1) produce consecutive moves in proximal board locations, (2) move more often the same piece and (3) reduce the number of remaining pieces more rapidly, most likely to decrease cognitive load and mental effort. These three principles might reflect the effect of expertise on human actions in complex setups. PMID:24550869

Divergent oral cavity motor strategies between healthy elite and dystonic horn players.

PubMed

Iltis, Peter W; Frahm, Jens; Voit, Dirk; Joseph, Arun; Schoonderwaldt, Erwin; Altenmüller, Eckart

2015-01-01

This paper describes the use of real-time magnetic resonance imaging in visualizing and quantifying oral cavity motor strategies employed by 6 healthy, elite horn players and 5 horn players with embouchure dystonia. Serial images with an acquisition time of 33.3 ms were obtained from each performer during execution of an 11-note harmonic series encompassing 2.5 octaves on a magnetic resonance imaging-compatible horn. A customized MATLAB toolkit was employed for the extraction of line profiles from magnetic resonance imaging films allowing comparative analyses between elite and dystonic horn players. The data demonstrate differing motor strategies, particularly in moving from the 6th through 9th harmonics. The elite horn player strategy features elevation and anterior displacement of the tongue during ascending sequences, whereas dystonic players showed significantly less movement. The elite horn players thus narrowed the air channel on higher notes, presumably affording faster airflow for vibration of the lips at higher frequencies. We postulate that failure to employ this strategy by dystonic horn players may require greater tension in the embouchure muscles to compensate for slower air speed. Though this may simply be an expression of or adaptation for dystonia, the possibility that it may be a contributing factor in the development of embouchure dystonia is suggested.

Unintended imitation affects success in a competitive game.

PubMed

Naber, Marnix; Vaziri Pashkam, Maryam; Nakayama, Ken

2013-12-10

Imitation typically occurs in social contexts where people interact and have common goals. Here, we show that people are also highly susceptible to imitate each other in a competitive context. Pairs of players performed a competitive and fast-reaching task (a variant of the arcade whac-a-mole game) in which money could be earned if players hit brief-appearing visual targets on a large touchscreen before their opponents. In three separate experiments, we demonstrate that reaction times and movements were highly correlated within pairs of players. Players affected their success by imitating each other, and imitation depended on the visibility of the opponent's behavior. Imitation persisted, despite the competitive and demanding nature of the game, even if this resulted in lower scores and payoffs and even when there was no need to counteract the opponent's actions.

Activity Profiles in International Women's Team Handball Using PlayerLoad.

PubMed

Wik, Eirik H; Luteberget, Live S; Spencer, Matt

2017-08-01

Team handball matches place diverse physical demands on players, which may result in fatigue and decreased activity levels. However, previous speed-based methods of quantifying player activity may not be sensitive for capturing short-lasting team-handball-specific movements. To examine activity profiles of a women's team handball team and individual player profiles, using inertial measurement units. Match data were obtained from 1 women's national team in 9 international matches (N = 85 individual player samples), using the Catapult OptimEye S5. PlayerLoad/min was used as a measure of intensity in 5- and 10-min periods. Team profiles were presented as relative to the player's match means, and individual profiles were presented as relative to the mean of the 5-min periods with >60% field time. A high initial intensity was observed for team profiles and for players with ≥2 consecutive periods of play. Substantial declines in PlayerLoad/min were observed throughout matches for the team and for players with several consecutive periods of field time. These trends were found for all positional categories. Intensity increased substantially in the final 5 min of the first half for team profiles. Activity levels were substantially lower in the 5 min after a player's most intense period and were partly restored in the subsequent 5-min period. Possible explanations for the observed declines in activity profiles for the team and individual players include fatigue, situational factors, and pacing. However, underlying mechanisms were not accounted for, and these assumptions are therefore based on previous team-sport studies.

Effects of small-sided games on physical conditioning and performance in young soccer players.

PubMed

Katis, Athanasios; Kellis, Eleftherios

2009-01-01

The purpose of this study was to examine, first, the movement actions performed during two different small-sided games and, second, their effects on a series of field endurance and technical tests. Thirty-four young soccer players (age: 13 ± 0.9 yrs; body mass: 62.3 ± 15.1 kg; height: 1.65 ± 0.06 m) participated in the study. Small-sided games included three-a-side (3 versus 3 players) and six-a-side (6 versus 6 players) games consisting of 10 bouts of 4 min duration with 3 min active recovery between bouts. Soccer player performance was evaluated using five field tests: a) 30m sprint, b) throw-in for distance, c) Illinois Agility Test, d) dribbling the ball and e) horizontal jump before, in the middle and after the implementation of both game situations. Heart rate was monitored during the entire testing session. Each game was also filmed to measure soccer movements within the game. The ANOVA analysis indicated that the three-a- side games displayed significantly higher heart rate values compared with the six-a-side games (p < 0.05). The number of short passes, kicks, tackles, dribbles and scoring goals were significantly higher during the three-a-side compared with the six-a-side game condition (p < 0. 05) while players performed more long passes and headed the ball more often during the six-a-side (p < 0.05). After the three-a-side games, there was a significant decline in sprint and agility performance (p < 0.05), while after both game conditions significant alterations in the throw-in and the horizontal jump performance were observed (p < 0.05). The results of the present study indicated that three-a-side games provide higher stimulus for physical conditioning and technical improvement than six-a-side games and their use for training young soccer players is recommended. Key pointsThree-a-side games display higher HR compared with six-a-side games.In the three-a-side games players performed more short passes, kicks, dribbles, tackles and scored more goals compared with the six-a-side games.Impairment in endurance and field test performance was observed mainly after three-a-side games.The use of the three-a-side games to develop physical fitness and technique in young soccer players is recommended.

Difference in plantar pressure between the preferred and non‐preferred feet in four soccer‐related movements

PubMed Central

Wong, Pui‐lam; Chamari, Karim; Chaouachi, Anis; De Wei Mao; Wisløff, Ulrik; Hong, Youlian

2007-01-01

Objective and participants The present study measured the difference in plantar pressure between the preferred and non‐preferred foot in four soccer‐related movements in 15 male university soccer players (mean (SD) age 20.9 (1.3) years, mean (SD) height 173 (4) cm and mean (SD) weight 61.7 (3.6) kg). Design To record plantar pressure distribution, players randomly wore three types of soccer shoes (classical 6‐stud and 12‐stud, and specially designed 12‐stud) embedded with an insole pressure recorder device with 99 sensors, divided into 10 areas for analysis. Plantar pressure was recorded in five successful trials in each of the four soccer‐related movements: running (at 3.3 m/s), sideward cutting, 45° cutting and landing from a vertical jump. Results Plantar pressures of the preferred and non‐preferred foot were different in 115 of 120 comparisons. The overall plantar pressure of the preferred foot was higher than that of the non‐preferred foot. Specifically, in each of the four movements, higher pressure was found in the preferred foot during the take‐off phase, whereas this was found in the non‐preferred foot during the landing phase. This would suggest a tendency of the preferred foot for higher motion force and of the non‐preferred foot for a greater role in body stabilisation. Conclusions The data indicate that the preferred and non‐preferred foot should be treated independently with regard to strength/power training to avoid unnecessary injuries. Different shoes/insoles and different muscular strengthening programmes are thus suggested for each of the soccer player's feet. PMID:17138639

Real-time MRI comparisons of brass players: A methodological pilot study.

PubMed

Iltis, Peter W; Schoonderwaldt, Erwin; Zhang, Shuo; Frahm, Jens; Altenmüller, Eckart

2015-08-01

This paper describes the use of real-time MRI at 30 frames/s in studying motor function within the oropharyngeal cavity of a trumpet, horn, trombone, and tuba player. Using Image J and customized MB-Ruler Pro software, analyses of discrete 33.3 ms snapshots of motion extracted from real-time MRI films obtained during an ascending five note sequence performed on a plastic practice device (B.E.R.P.) revealed inter-instrument differences in oropharyngeal cavity size and tongue conformation when moving from lower to higher notes. Tuba and trombone show a progressive decrease in oropharyngeal area featuring an upward and forward displacement of the tongue. Trumpet showed progressive increases in oropharyngeal area, with the posterior compartment showing the largest change, while horn essentially showed no change. A novel dynamic quantitative analysis method is also described utilizing Matlab. This method employs user-specified line profiles, aligned to the direction of the movement of interest. It takes advantage of time-varying pixel luminescence to derive spatial and temporal gradients. These gradients make possible the acquisition of kinematic data to describe movement in terms of slower position changes (spatial gradient) as well as fast, articulatory movements (temporal gradient). Spatial gradient analysis for the trumpet player demonstrates a progressive raising of the tongue during the ascending five note exercise. Temporal gradient analysis of double-tonguing revealed similarities in range of motion, anti-phase behavior, and frequency across instruments with respect to movements of the tongue tip and back of tongue. The paper concludes by making recommendations for extending these methods to studying musician's dystonia. Copyright © 2015 Elsevier B.V. All rights reserved.

Suitability of FIFA's "The 11" Training Programme for Young Football Players - Impact on Physical Performance.

PubMed

Kilding, Andrew E; Tunstall, Helen; Kuzmic, Dejan

2008-01-01

There is a paucity of evidence regarding the use of injury prevention programmes for preadolescents participating in sport. "The 11 "injury prevention programme was developed by FIFA's medical research centre (F-MARC) to help reduce the risk of injury in football players aged 14 years and over. The aim of this study was to determine the suitability and effectiveness of "The 11 "for younger football players. Twenty-four [12 experimental (EXP), 12 control (CON)] young football players (age 10.4 ± 1.4 yr) participated. The EXP group followed "The 11 "training programme 5 days per week, for 6 weeks, completing all but one of the 10 exercises. Prior to, and after the intervention, both EXP and CON groups performed a battery of football-specific physical tests. Changes in performance scores within each group were compared using independent t-tests (p ≤ 0.05). Feedback was also gathered on the young players' perceptions of "The 11". No injuries occurred during the study in either group. Compliance to the intervention was 72%. Measures of leg power (3 step jump and counter-movement jump) increased significantly (3.4 and 6.0% respectively, p < 0.05). Speed over 20 m improved by 2% (p < 0.05). Most players considered "The 11 "beneficial but not enjoyable in the prescribed format. Given the observed improvements in the physical abilities and the perceived benefits of "The 11", it would appear that a modified version of the programme is appropriate and should be included in the training of young football players, for both physical development and potential injury prevention purposes, as well as to promote fair play. To further engage young football players in such a programme, some modification to "The 11 "should be considered. Key pointsChildren who participate in recreational and competitive sports, especially football, are susceptible to injury.There is a need for the design and assessment of injury prevention programmes for children.The 11 "improves essential physical performance characteristics and has the potential to reduce the risk of injury.It may be prudent to implement a 'child-friendly' version of "The 11", to enhance long-term programme adherence and to ensure progressive physical development of players.

Sports teams as complex adaptive systems: manipulating player numbers shapes behaviours during football small-sided games.

PubMed

Silva, Pedro; Vilar, Luís; Davids, Keith; Araújo, Duarte; Garganta, Júlio

2016-01-01

Small-sided and conditioned games (SSCGs) in sport have been modelled as complex adaptive systems. Research has shown that the relative space per player (RSP) formulated in SSCGs can impact on emergent tactical behaviours. In this study we adopted a systems orientation to analyse how different RSP values, obtained through manipulations of player numbers, influenced four measures of interpersonal coordination observed during performance in SSCGs. For this purpose we calculated positional data (GPS 15 Hz) from ten U-15 football players performing in three SSCGs varying in player numbers (3v3, 4v4 and 5v5). Key measures of SSCG system behaviours included values of (1) players' dispersion, (2) teams' separateness, (3) coupling strength and time delays between participants' emerging movements, respectively. Results showed that values of participants' dispersion increased, but the teams' separateness remained identical across treatments. Coupling strength and time delay also showed consistent values across SSCGs. These results exemplified how complex adaptive systems, like football teams, can harness inherent degeneracy to maintain similar team spatial-temporal relations with opponents through changes in inter-individual coordination modes (i.e., players' dispersion). The results imply that different team behaviours might emerge at different ratios of field dimension/player numbers. Therefore, sport pedagogists should carefully evaluate the effects of changing RSP in SSCGs as a way of promoting increased or decreased pressure on players.

Movement Demands of Elite Under-20s and Senior International Rugby Union Players

PubMed Central

Drawer, Scott; Pollard, Ben; Eager, Robin; Taylor, Neil; Cook, Christian J.

2016-01-01

This study compared the movement demands of elite international Under-20 age grade (U20s) and senior international rugby union players during competitive tournament match play. Forty elite professional players from an U20 and 27 elite professional senior players from international performance squads were monitored using 10Hz global positioning systems (GPS) during 15 (U20s) and 8 (senior) international tournament matches during the 2014 and 2015 seasons. Data on distances, velocities, accelerations, decelerations, high metabolic load (HML) distance and efforts, and number of sprints were derived. Data files from players who played over 60 min (n = 258) were separated firstly into Forwards and Backs, and more specifically into six positional groups; FR–Front Row (prop & hooker), SR–Second Row, BR–Back Row (Flankers & No.8), HB–Half Backs (scrum half & outside half), MF–Midfield (centres), B3 –Back Three (wings & full back) for match analysis. Linear mixed models revealed significant differences between U20 and senior teams in both the forwards and backs. In the forwards the seniors covered greater HML distance (736.4 ± 280.3 vs 701.3 ± 198.7m, p = 0.01) and severe decelerations (2.38 ± 2.2 vs 2.28 ± 1.65, p = 0.05) compared to the U20s, but performed less relative HSR (3.1 ± 1.6 vs 3.2 ± 1.5, p < 0.01), moderate (19.4 ± 10.5 vs 23.6 ± 10.5, p = 0.01) and high accelerations (2.2 ± 1.9 vs 4.3 ± 2.7, p < 0.01) and sprint•min-1 (0.11 ± 0.06 vs 0.11 ± 0.05, p < 0.01). Senior backs covered a greater relative distance (73.3 ± 8.1 vs 69.1 ± 7.6 m•min-1, p < 0.01), greater High Metabolic Load (HML) distance (1138.0 ± 233.5 vs 1060.4 ± 218.1m, p < 0.01), HML efforts (112.7 ± 22.2 vs 98.8 ± 21.7, p < 0.01) and heavy decelerations (9.9 ± 4.3 vs 9.5 ± 4.4, p = 0.04) than the U20s backs. However, the U20s backs performed more relative HSR (7.3 ± 2.1 vs 7.2 ± 2.1, p <0.01) and sprint•min-1 (0.26 ± 0.07 vs 0.25 ± 0.07, p < 0.01). Further investigation highlighted differences between the 6 positional groups of the teams. The positional groups that differed the most on the variables measured were the FR and MF groups, with the U20s FR having higher outputs on HSR, moderate & high accelerations, moderate, high & severe decelerations, HML distance, HML efforts, and sprints•min-1. For the MF group the senior players produced greater values for relative distance covered, HSR, moderate decelerations, HML distance and sprint•min-1. The BR position group was most similar with the only differences seen on heavy accelerations (U20s higher) and moderate decelerations (seniors higher). Findings demonstrate that U20s internationals appear to be an adequate ‘stepping stone’ for preparing players for movement characteristics found senior International rugby, however, the current study highlight for the first time that certain positional groups may require more time to be able to match the movement demands required at a higher playing level than others. Conditioning staff must also bear in mind that the U20s players whilst maintaining or improving match movement capabilities may require to gain substantial mass in some positions to match their senior counterparts. PMID:27824865

Movement Demands of Elite Under-20s and Senior International Rugby Union Players.

PubMed

Cunningham, Daniel J; Shearer, David A; Drawer, Scott; Pollard, Ben; Eager, Robin; Taylor, Neil; Cook, Christian J; Kilduff, Liam P

2016-01-01

This study compared the movement demands of elite international Under-20 age grade (U20s) and senior international rugby union players during competitive tournament match play. Forty elite professional players from an U20 and 27 elite professional senior players from international performance squads were monitored using 10Hz global positioning systems (GPS) during 15 (U20s) and 8 (senior) international tournament matches during the 2014 and 2015 seasons. Data on distances, velocities, accelerations, decelerations, high metabolic load (HML) distance and efforts, and number of sprints were derived. Data files from players who played over 60 min (n = 258) were separated firstly into Forwards and Backs, and more specifically into six positional groups; FR-Front Row (prop & hooker), SR-Second Row, BR-Back Row (Flankers & No.8), HB-Half Backs (scrum half & outside half), MF-Midfield (centres), B3 -Back Three (wings & full back) for match analysis. Linear mixed models revealed significant differences between U20 and senior teams in both the forwards and backs. In the forwards the seniors covered greater HML distance (736.4 ± 280.3 vs 701.3 ± 198.7m, p = 0.01) and severe decelerations (2.38 ± 2.2 vs 2.28 ± 1.65, p = 0.05) compared to the U20s, but performed less relative HSR (3.1 ± 1.6 vs 3.2 ± 1.5, p < 0.01), moderate (19.4 ± 10.5 vs 23.6 ± 10.5, p = 0.01) and high accelerations (2.2 ± 1.9 vs 4.3 ± 2.7, p < 0.01) and sprint•min-1 (0.11 ± 0.06 vs 0.11 ± 0.05, p < 0.01). Senior backs covered a greater relative distance (73.3 ± 8.1 vs 69.1 ± 7.6 m•min-1, p < 0.01), greater High Metabolic Load (HML) distance (1138.0 ± 233.5 vs 1060.4 ± 218.1m, p < 0.01), HML efforts (112.7 ± 22.2 vs 98.8 ± 21.7, p < 0.01) and heavy decelerations (9.9 ± 4.3 vs 9.5 ± 4.4, p = 0.04) than the U20s backs. However, the U20s backs performed more relative HSR (7.3 ± 2.1 vs 7.2 ± 2.1, p <0.01) and sprint•min-1 (0.26 ± 0.07 vs 0.25 ± 0.07, p < 0.01). Further investigation highlighted differences between the 6 positional groups of the teams. The positional groups that differed the most on the variables measured were the FR and MF groups, with the U20s FR having higher outputs on HSR, moderate & high accelerations, moderate, high & severe decelerations, HML distance, HML efforts, and sprints•min-1. For the MF group the senior players produced greater values for relative distance covered, HSR, moderate decelerations, HML distance and sprint•min-1. The BR position group was most similar with the only differences seen on heavy accelerations (U20s higher) and moderate decelerations (seniors higher). Findings demonstrate that U20s internationals appear to be an adequate 'stepping stone' for preparing players for movement characteristics found senior International rugby, however, the current study highlight for the first time that certain positional groups may require more time to be able to match the movement demands required at a higher playing level than others. Conditioning staff must also bear in mind that the U20s players whilst maintaining or improving match movement capabilities may require to gain substantial mass in some positions to match their senior counterparts.

Player Load, Acceleration, and Deceleration During Forty-Five Competitive Matches of Elite Soccer.

PubMed

Dalen, Terje; Ingebrigtsen, Jørgen; Ettema, Gertjan; Hjelde, Geir Havard; Wisløff, Ulrik

2016-02-01

The use of time-motion analysis has advanced our understanding of position-specific work rate profiles and the physical requirements of soccer players. Still, many of the typical soccer activities can be neglected, as these systems only examine activities measured by distance and speed variables. This study used triaxial accelerometer and time-motion analysis to obtain new knowledge about elite soccer players' match load. Furthermore, we determined acceleration/deceleration profiles of elite soccer players and their contribution to the players' match load. The data set includes every domestic home game (n = 45) covering 3 full seasons (2009, 2010, and 2011) for the participating team (Rosenborg FC), and includes 8 central defenders (n = 68), 9 fullbacks (n = 83), 9 central midfielders (n = 70), 7 wide midfielders (n = 39), and 5 attackers (A, n = 50). A novel finding was that accelerations contributed to 7-10% of the total player load for all player positions, whereas decelerations contributed to 5-7%. Furthermore, the results indicate that other activities besides the high-intensity movements contribute significantly to the players' total match workload. Therefore, motion analysis alone may underestimate player load because many high-intensity actions are without a change in location at the pitch or they are classified as low-speed activity according to current standards. This new knowledge may help coaches to better understand the different ways players achieve match load and could be used in developing individualized programs that better meet the "positional physical demands" in elite soccer.

Genetics Home Reference: congenital mirror movement disorder

MedlinePlus

... Accessibility FOIA Viewers & Players U.S. Department of Health & Human Services National Institutes of Health National Library of Medicine Lister Hill National Center for Biomedical Communications 8600 Rockville Pike, Bethesda, MD 20894, USA HONCode ...

Looking to Score: The Dissociation of Goal Influence on Eye Movement and Meta-Attentional Allocation in a Complex Dynamic Natural Scene

PubMed Central

Taya, Shuichiro; Windridge, David; Osman, Magda

2012-01-01

Several studies have reported that task instructions influence eye-movement behavior during static image observation. In contrast, during dynamic scene observation we show that while the specificity of the goal of a task influences observers’ beliefs about where they look, the goal does not in turn influence eye-movement patterns. In our study observers watched short video clips of a single tennis match and were asked to make subjective judgments about the allocation of visual attention to the items presented in the clip (e.g., ball, players, court lines, and umpire). However, before attending to the clips, observers were either told to simply watch clips (non-specific goal), or they were told to watch the clips with a view to judging which of the two tennis players was awarded the point (specific goal). The results of subjective reports suggest that observers believed that they allocated their attention more to goal-related items (e.g. court lines) if they performed the goal-specific task. However, we did not find the effect of goal specificity on major eye-movement parameters (i.e., saccadic amplitudes, inter-saccadic intervals, and gaze coherence). We conclude that the specificity of a task goal can alter observer’s beliefs about their attention allocation strategy, but such task-driven meta-attentional modulation does not necessarily correlate with eye-movement behavior. PMID:22768058

Somatotype variables related to strength and power output in male basketball players.

PubMed

Buśko, Krzysztof; Pastuszak, Anna; Lipińska, Monika; Lipińska, Marta; Gryko, Karol

2017-01-01

The purpose of this study was to investigate the relationship between somatotype, muscular strength, power output measured in maximal cycle ergometer exercise bouts, and maximal power output and height of rise of the body mass centre (jump height) measured in akimbo counter movement jump (ACMJ), counter movement jump (CMJ) and spike jump (SPJ), in male basketball players. Thirteen male basketball players (second division, age 19.4 ± 0.8 years, body height 192.9 ± 5.6 cm, body mass 88.8 ± 8.6 kg, training experience 9.3 ± 0.8 years) participated in the study. Somatotype was determined using the Heath-Carter method. Maximal joint torques were measured under static conditions. Power output was measured in 2 maximal cycle ergometer exercise bouts, 10 seconds each, with increasing external loads equal to 7.5 and 10.0% of the body weight (BW). All jump trials (ACMJ, CMJ and SPJ) were performed on a force plate. The mean somatotype of basketball players amounted to: 2.8-4.2-3.2. The sum of the joint torques for left and right lower extremities (0.613), trunk (0.631) and all six measured muscle groups (0.647) were significantly correlated (p < 0.05) with the mesomorphic component. Endomorphic, mesomorphic and ectomorphic components were correlated insignificantly with values of maximal power and height of jump during ACMJ, CMJ and SPJ trials. The power output measured in maximal cycle ergometer exercise bouts with increasing external loads was significantly correlated (p < 0.05) with mesomorphy and ectomorphy. It can be assumed that basketball players' anthropometric characteristics can influence their level of performance but it is not a decisive factor.

Elite football on artificial turf versus natural grass: movement patterns, technical standards, and player impressions.

PubMed

Andersson, Helena; Ekblom, Björn; Krustrup, Peter

2008-01-15

The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.

Biomotor structures in elite female handball players according to performance.

PubMed

Cavala, Marijana; Rogulj, Nenad; Srhoj, Vatromir; Srhoj, Ljerka; Katić, Ratko

2008-03-01

In order to identify biomotor structures in elite female handball players, factor structures of morphological characteristics and basic motor abilities, and of variables evaluating situation motor abilities of elite female handball players (n = 53) were determined first, followed by determination of differences and relations of the morphological, motor and specific motor space according to handball performance. Factor analysis of 16 morphological measures produced three morphological factors, i.e. factor of absolute voluminosity, i.e. mesoendomorphy, factor of longitudinal skeleton dimensionality, and factor of transverse hand dimensionality. Factor analysis of 15 motor variables yielded five basic motor dimensions, i.e. factor of agility, factor of throwing explosive strength, factor of running explosive strength (sprint), factor of jumping explosive strength and factor of movement frequency rate. Factor analysis of 5 situation motor variables produced two dimensions: factor of specific agility with explosiveness and factor of specific precision with ball manipulation. Analysis of variance yielded greatest differences relative to handball performance in the factor of specific agility and throwing strength, and the factor of basic motoricity that integrates the ability of coordination (agility) with upper extremity throwing explosiveness and lower extremity sprint (30-m sprint) and jumping (standing triple jump). Considering morphological factors, the factor of voluminosity, i.e. mesoendomorphy, which is defined by muscle mass rather than adipose tissue, was found to contribute significantly to the players'performance. Results of regression analysis indicated the handball performance to be predominantly determined by the general specific motor factor based on specific agility and explosiveness, and by the morphological factor based on body mass and volume, i.e. muscle mass. Concerning basic motor abilities, the factor of movement frequency rate, which is associated with the ability of ball manipulation, was observed to predict significantly the handball players' performance.

Anthropometric and physical performance characteristics of top-elite, elite and non-elite youth female team handball players.

PubMed

Moss, Samantha Louise; McWhannell, Nicola; Michalsik, Lars Bojsen; Twist, Craig

2015-01-01

In order to maximise the potential for success, developing nations need to produce superior systems to identify and develop talent, which requires comprehensive and up-to-date values on elite players. This study examined the anthropometric and physical characteristics of youth female team handball players (16.07 ± 1.30 years) in non-elite (n = 47), elite (n = 37) and top-elite players (n = 29). Anthropometric profiling included sum of eight skinfolds, body mass, stature, girths, breadths and somatotype. Performance tests included 20 m sprint, counter-movement jump, throwing velocity, repeated shuttle sprint and jump ability test, and Yo-Yo Intermittent Recovery Test Level 1. Youth top-elite players had greater body mass, lean mass, stature, limb girths and breadths than elite and non-elite players, while only stature and flexed arm were higher in elite compared to non-elite players (all P < 0.05). Sum of skinfolds and waist-to-hip ratio were similar between groups (P > 0.05). Top-elite performed better in most performance tests compared to both elite and non-elite players (P < 0.05), although maximal and repeated 10 m sprints were similar between playing standards (P > 0.05). Elite outperformed non-elite players only in throwing velocity. The findings reveal that non-elite players compare unfavourably to top-elite international European players in many anthropometric and performance characteristics, and differ in a few characteristics compared to elite European club team players. This study is useful for emerging team handball nations in improving talent identification processes.

Split-Step Timing of Professional and Junior Tennis Players

PubMed Central

Leskosek, Bojan; Filipcic, Tjasa

2017-01-01

Abstract The purpose of the study was to determine the timing of a split-step in three categories of tennis players in four groups of strokes. Subjects were divided into three groups: male and female junior, and male professional tennis players. During two tournaments, all matches were recorded with two fixed video cameras. For every stroke, the timing of the split-step between the opponent’s impact point when hitting the ball and the player’s split-step was measured. A two-way analysis of variance (ANOVA) was used to determine the differences between groups of strokes, players and the interaction Player x Stroke Group. A Tukey post-hoc test was employed to determine specific differences. The results revealed differences between players in detecting the opponent’s movement, stroke and ball flight, which were reflected in different split-step timings. Each tennis player has his/her own timing mechanism which they adapt to various game situations. Response times differ significantly depending on the game situation. On average, they are the lowest in the serve, and then gradually rise from the return of the serve to baseline game, reaching the highest values in specific game situations. Players react faster in the first serve than in the second one and in the return of the serve, the response times are lower after the return of the second serve PMID:28210342

Mechanisms of anterior cruciate ligament injuries in elite women's netball: a systematic video analysis.

PubMed

Stuelcken, Max C; Mellifont, Daniel B; Gorman, Adam D; Sayers, Mark G L

2016-08-01

This study involved a systematic video analysis of 16 anterior cruciate ligament (ACL) injuries sustained by elite-level netball players during televised games in order to describe the game situation, the movement patterns involved, the player's behaviour, and a potential injury mechanism. Eight of the ACL injuries were classified as "indirect contact" and eight as "non-contact". Two common scenarios were identified. In Scenario A the player was jumping to receive or intercept a pass and whilst competing for the ball experienced a perturbation in the air. As a result the player's landing was unbalanced with loading occurring predominantly on the knee of the injured side. In Scenario B the player was generally in a good position at ground contact, but then noticeably altered the alignment of the trunk before the landing was completed. This involved rotating and laterally flexing the trunk without altering the alignment of the feet. Apparent knee valgus collapse on the knee of the injured side was observed in 3/6 Scenario A cases and 5/6 Scenario B cases. Players may benefit from landing training programmes that incorporate tasks that use a ball and include decision-making components or require players to learn to cope with being unbalanced.

Countermovement-Jump-Phase Characteristics of Senior and Academy Rugby League Players.

PubMed

McMahon, John J; Murphy, Shannon; Rej, Sophie J E; Comfort, Paul

2017-07-01

Gross measures of countermovement-jump (CMJ) performance are commonly used to track maturational changes in neuromuscular function in rugby league (RL). The purpose of this study was to conduct both a gross and a more detailed temporal-phase analysis of the CMJ performances of senior and academy RL players, to provide greater insight into how neuromuscular function differs between these groups. Twenty senior and 14 academy (under-19) male RL players performed 3 maximal-effort CMJs on a force platform, with forward dynamics subsequently employed to allow gross performance measures and entire kinetic- and kinematic-time curves to be compared between groups. Jump height (JH), reactive strength index modified, concentric displacement, and relative concentric impulse (C-IMP) were the only gross measures that were greater for senior players (d = 0.58-0.91) than for academy players. The relative force- and displacement-time curves were similar between groups, but the relative power- and velocity-time curves were greater (d = 0.59-0.97) for the senior players at 94-96% and 89-100% of the total movement time, respectively. The CMJ distinguished between senior and academy RL players, with seniors demonstrating greater JH through applying a larger C-IMP and thus achieving greater velocity throughout the majority of the concentric phase and at takeoff. Therefore, academy RL players should train to improve triple (ie, ankle, knee, and hip) extension velocity during the CMJ to bring their JH scores in line with those attained by senior players.

Effect of Core Training on Male Handball Players' Throwing Velocity.

PubMed

Manchado, Carmen; García-Ruiz, José; Cortell-Tormo, Juan Manuel; Tortosa-Martínez, Juan

2017-02-01

In handball, throwing velocity is considered to be one of the essential factors in achieving the ultimate aim of scoring a goal. The objective of the present study was to analyze the effect of a core training program on throwing velocity in 30 handball players (age 18.7 ± 3.4 years, body height 179.3 ± 7.0 cm, body mass 78.9 ± 7.7 kg), 16 of whom were in the junior category and 14 of whom were in the senior category. The 30 players were randomly divided into two groups, the control group (n = 15) and the experimental group (n = 15). For a period of ten weeks, both groups attended their regular handball training sessions (four per week), but in addition, the experimental group participated in a program specifically aimed at progressively strengthening the lumbo-pelvic region and consisting of seven exercises performed after the general warm-up in each regular session. Pre- and post-tests were carried out to analyze each player's throwing velocity from different throwing positions and thus assess the effects of this specific training program. Statistically significant differences (p ≤ 0.05) in throwing velocity were observed between the experimental group, which presented a percentage improvement of 4.5%, and the control group, which did not show any improvement. The results seem to indicate that an increase in the strength and stability of the lumbo-pelvic region can contribute to an improvement in the kinetic chain of the specific movement of throwing in handball, thus, increasing throwing velocity.

Eye movement accuracy determines natural interception strategies.

PubMed

Fooken, Jolande; Yeo, Sang-Hoon; Pai, Dinesh K; Spering, Miriam

2016-11-01

Eye movements aid visual perception and guide actions such as reaching or grasping. Most previous work on eye-hand coordination has focused on saccadic eye movements. Here we show that smooth pursuit eye movement accuracy strongly predicts both interception accuracy and the strategy used to intercept a moving object. We developed a naturalistic task in which participants (n = 42 varsity baseball players) intercepted a moving dot (a "2D fly ball") with their index finger in a designated "hit zone." Participants were instructed to track the ball with their eyes, but were only shown its initial launch (100-300 ms). Better smooth pursuit resulted in more accurate interceptions and determined the strategy used for interception, i.e., whether interception was early or late in the hit zone. Even though early and late interceptors showed equally accurate interceptions, they may have relied on distinct tactics: early interceptors used cognitive heuristics, whereas late interceptors' performance was best predicted by pursuit accuracy. Late interception may be beneficial in real-world tasks as it provides more time for decision and adjustment. Supporting this view, baseball players who were more senior were more likely to be late interceptors. Our findings suggest that interception strategies are optimally adapted to the proficiency of the pursuit system.

Knee strength ratios in competitive female athletes

PubMed Central

Murawa, Michal; Mackala, Krzysztof; Dworak, Lechoslaw Bogdan

2018-01-01

Knee strength ratios are related to the movement patterns, sport-specific training and knee injuries in athletes. The purpose of this study was to determine the ratios in the concentric isokinetic strength of the hamstrings and quadriceps and the isometric strength of the knee extensors. In female basketball players (n = 14) and female volleyball players (n = 12) were evaluated: the hamstrings to quadriceps peak torque ratio (H/Q) and side-to-side peak torque ratio (TR) for hamstrings and quadriceps; the ratio of the maximal bilateral strength to the summed maximal unilateral strength (B/U) and side-to-side maximal strength ratio (SR) for knee extensors. For the H/Q values, a 2 × 2 × 3 mixed-factorial analysis of variance and Bonferroni post hoc test were computed. The H/Q values increased from 48.0 (3.9)% at 60°/s to 70.4 (7.9)% at 300°/s. Furthermore, there were significant differences in the H/Q values between 300°/s and 180°/s, 300°/s and 60°/s in basketball and volleyball athletes, and between 180°/s and 60°/s only in basketball athletes (p < .05). Significantly higher H/Q results at 60°/s demonstrated basketball players than volleyball players (p < .05). Differences in the TR and SR mean values ranged from 4.4% to 8.6% and indicated no significant side-to-side strength deficits (p > .05). In both groups, greater isometric strength developed bilaterally was found (B/U > 100%). The findings revealed the magnitude of knee strength ratios in female athletes determined by sport-specific movements in basketball and volleyball. This study highlighted the importance of the bilateral strength deficit and muscular balance between the hamstrings and quadriceps in basketball and volleyball athletes in activities related to their movement patterns and specific training. PMID:29315348

Neural network modelling and dynamical system theory: are they relevant to study the governing dynamics of association football players?

PubMed

Dutt-Mazumder, Aviroop; Button, Chris; Robins, Anthony; Bartlett, Roger

2011-12-01

Recent studies have explored the organization of player movements in team sports using a range of statistical tools. However, the factors that best explain the performance of association football teams remain elusive. Arguably, this is due to the high-dimensional behavioural outputs that illustrate the complex, evolving configurations typical of team games. According to dynamical system analysts, movement patterns in team sports exhibit nonlinear self-organizing features. Nonlinear processing tools (i.e. Artificial Neural Networks; ANNs) are becoming increasingly popular to investigate the coordination of participants in sports competitions. ANNs are well suited to describing high-dimensional data sets with nonlinear attributes, however, limited information concerning the processes required to apply ANNs exists. This review investigates the relative value of various ANN learning approaches used in sports performance analysis of team sports focusing on potential applications for association football. Sixty-two research sources were summarized and reviewed from electronic literature search engines such as SPORTDiscus, Google Scholar, IEEE Xplore, Scirus, ScienceDirect and Elsevier. Typical ANN learning algorithms can be adapted to perform pattern recognition and pattern classification. Particularly, dimensionality reduction by a Kohonen feature map (KFM) can compress chaotic high-dimensional datasets into low-dimensional relevant information. Such information would be useful for developing effective training drills that should enhance self-organizing coordination among players. We conclude that ANN-based qualitative analysis is a promising approach to understand the dynamical attributes of association football players.

Neuromuscular Taping Application in Counter Movement Jump: Biomechanical Insight in a Group of Healthy Basketball Players.

PubMed

Marcolin, Giuseppe; Buriani, Alessandro; Giacomelli, Andrea; Blow, David; Grigoletto, Davide; Gesi, Marco

2017-06-24

Kinesiologic elastic tape is widely used for both clinical and sport applications although its efficacy in enhancing agonistic performance is still controversial. Aim of the study was to verify in a group of healthy basketball players whether a neuromuscular taping application (NMT) on ankle and knee joints could affect the kinematic and the kinetic parameters of the jump, either by enhancing or inhibiting the functional performance. Fourteen healthy male basketball players without any ongoing pathologies at upper limbs, lower limbs and trunk volunteered in the study. They randomly performed 2 sets of 5 counter movement jumps (CMJ) with and without application of Kinesiologic tape. The best 3 jumps of each set were considered for the analysis. The Kinematics parameters analyzed were: knees maximal flexion and ankles maximal dorsiflexion during the push off phase, jump height and take off velocity. Vertical ground reaction force and maximal power expressed in the push off phase of the jump were also investigated. The NMT application in both knees and ankles showed no statistically significant differences in the kinematic and kinetic parameters and did not interfere with the CMJ performance. Bilateral NMT application in the group of healthy male basketball players did not change kinematics and kinetics jump parameters, thus suggesting that its routine use should have no negative effect on functional performance. Similarly, the combined application of the tape on both knees and ankles did not affect in either way jump performance.

Neuromuscular Taping Application in Counter Movement Jump: Biomechanical Insight in a Group of Healthy Basketball Players

PubMed Central

Marcolin, Giuseppe; Buriani, Alessandro; Giacomelli, Andrea; Blow, David; Grigoletto, Davide; Gesi, Marco

2017-01-01

Kinesiologic elastic tape is widely used for both clinical and sport applications although its efficacy in enhancing agonistic performance is still controversial. Aim of the study was to verify in a group of healthy basketball players whether a neuromuscular taping application (NMT) on ankle and knee joints could affect the kinematic and the kinetic parameters of the jump, either by enhancing or inhibiting the functional performance. Fourteen healthy male basketball players without any ongoing pathologies at upper limbs, lower limbs and trunk volunteered in the study. They randomly performed 2 sets of 5 counter movement jumps (CMJ) with and without application of Kinesiologic tape. The best 3 jumps of each set were considered for the analysis. The Kinematics parameters analyzed were: knees maximal flexion and ankles maximal dorsiflexion during the push off phase, jump height and take off velocity. Vertical ground reaction force and maximal power expressed in the push off phase of the jump were also investigated. The NMT application in both knees and ankles showed no statistically significant differences in the kinematic and kinetic parameters and did not interfere with the CMJ performance. Bilateral NMT application in the group of healthy male basketball players did not change kinematics and kinetics jump parameters, thus suggesting that its routine use should have no negative effect on functional performance. Similarly, the combined application of the tape on both knees and ankles did not affect in either way jump performance. PMID:28713536

Suitability of FIFA’s “The 11” Training Programme for Young Football Players – Impact on Physical Performance

PubMed Central

Kilding, Andrew E; Tunstall, Helen; Kuzmic, Dejan

2008-01-01

There is a paucity of evidence regarding the use of injury prevention programmes for preadolescents participating in sport. “The 11 ”injury prevention programme was developed by FIFA’s medical research centre (F-MARC) to help reduce the risk of injury in football players aged 14 years and over. The aim of this study was to determine the suitability and effectiveness of “The 11 ”for younger football players. Twenty-four [12 experimental (EXP), 12 control (CON)] young football players (age 10.4 ± 1.4 yr) participated. The EXP group followed “The 11 ”training programme 5 days per week, for 6 weeks, completing all but one of the 10 exercises. Prior to, and after the intervention, both EXP and CON groups performed a battery of football-specific physical tests. Changes in performance scores within each group were compared using independent t-tests (p ≤ 0.05). Feedback was also gathered on the young players’ perceptions of “The 11”. No injuries occurred during the study in either group. Compliance to the intervention was 72%. Measures of leg power (3 step jump and counter-movement jump) increased significantly (3.4 and 6.0% respectively, p < 0.05). Speed over 20 m improved by 2% (p < 0.05). Most players considered “The 11 ”beneficial but not enjoyable in the prescribed format. Given the observed improvements in the physical abilities and the perceived benefits of “The 11”, it would appear that a modified version of the programme is appropriate and should be included in the training of young football players, for both physical development and potential injury prevention purposes, as well as to promote fair play. To further engage young football players in such a programme, some modification to “The 11 ”should be considered. Key pointsChildren who participate in recreational and competitive sports, especially football, are susceptible to injury.There is a need for the design and assessment of injury prevention programmes for children.The 11 ”improves essential physical performance characteristics and has the potential to reduce the risk of injury.It may be prudent to implement a ‘child-friendly’ version of “The 11”, to enhance long-term programme adherence and to ensure progressive physical development of players. PMID:24149898

The effect of low back pain on trunk muscle size/function and hip strength in elite football (soccer) players.

PubMed

Hides, Julie A; Oostenbroek, Tim; Franettovich Smith, Melinda M; Mendis, M Dilani

2016-12-01

Low back pain (LBP) is a common problem in football (soccer) players. The effect of LBP on the trunk and hip muscles in this group is unknown. The relationship between LBP and trunk muscle size and function in football players across the preseason was examined. A secondary aim was to assess hip muscle strength. Twenty-five elite soccer players participated in the study, with assessments conducted on 23 players at both the start and end of the preseason. LBP was assessed with questionnaires and ultrasound imaging was used to assess size and function of trunk muscles at the start and end of preseason. Dynamometry was used to assess hip muscle strength at the start of the preseason. At the start of the preseason, 28% of players reported the presence of LBP and this was associated with reduced size of the multifidus, increased contraction of the transversus abdominis and multifidus muscles. LBP decreased across the preseason, and size of the multifidus muscle improved over the preseason. Ability to contract the abdominal and multifidus muscles did not alter across the preseason. Asymmetry in hip adductor and abductor muscle strength was found between players with and without LBP. Identifying modifiable factors in players with LBP may allow development of more targeted preseason rehabilitation programmes.

The fastest field sport in the world: A case report on 3-dimensional printed hurling gloves to help prevent injury.

PubMed

Harte, Daniel; Paterson, Abby

2017-10-28

Case series. Hand injuries are the most common injury observed in hurling although compliance in wearing protective gloves is reportedly low. To devise a glove that offers comfort, protection and freedom of movement, using the bespoke capabilities of 3-dimensional (3D) printing. Each player's "catching" hand was imaged using a 3D scanner to produce a bespoke glove that they later trialed and provided feedback. Nine players provided feedback. On average, the players favorably rated the glove for the protection offered. The average response on comfort was poor, and no players reported that glove aided performance during play. This feasibility study explores the versatility of 3D printing as a potential avenue to improve player compliance in wearing protective sportswear. Feedback will help refine glove design for future prototypes. Hurling is the primary focus in this study, but knowledge gains should be transferable to other sports that have a high incidence of hand injury. 4. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Strong correlation of maximal squat strength with sprint performance and vertical jump height in elite soccer players

PubMed Central

Wisloff, U; Castagna, C; Helgerud, J; Jones, R; Hoff, J

2004-01-01

Background: A high level of strength is inherent in elite soccer play, but the relation between maximal strength and sprint and jumping performance has not been studied thoroughly. Objective: To determine whether maximal strength correlates with sprint and vertical jump height in elite male soccer players. Methods: Seventeen international male soccer players (mean (SD) age 25.8 (2.9) years, height 177.3 (4.1) cm, weight 76.5 (7.6) kg, and maximal oxygen uptake 65.7 (4.3) ml/kg/min) were tested for maximal strength in half squats and sprinting ability (0–30 m and 10 m shuttle run sprint) and vertical jumping height. Result: There was a strong correlation between maximal strength in half squats and sprint performance and jumping height. Conclusions: Maximal strength in half squats determines sprint performance and jumping height in high level soccer players. High squat strength did not imply reduced maximal oxygen consumption. Elite soccer players should focus on maximal strength training, with emphasis on maximal mobilisation of concentric movements, which may improve their sprinting and jumping performance. PMID:15155427

Differences in Physical Capacity Between Junior and Senior Australian Footballers.

PubMed

Kelly, Stephen J; Watsford, Mark L; Austin, Damien J; Spurrs, Rob W; Pine, Matthew J; Rennie, Michael J

2017-11-01

Kelly, SJ, Watsford, ML, Austin, DJ, Spurrs, RW, Pine, MJ, and Rennie, MJ. Differences in physical capacity between junior and senior Australian footballers. J Strength Cond Res 31(11): 3059-3066, 2017-The purpose of this study was to profile and compare anthropometric and physical capacities within elite junior and senior Australian football (AF) players of various chronological ages and stages of athletic development. Seventy-nine players, including junior and senior AF players from one professional club, were profiled using 11 assessments. Junior players were divided into 2 groups based on chronological age (under 16 and 18 years) and senior players according to years since drafted to a professional AF team (1-2 years, 3-7 years, and 8+ years). Parametric data were assessed using a 1-way analysis of variance (ANOVA), whereas nonparametric data were assessed using a Kruskal-Wallis ANOVA. The magnitude difference between players was measured using the Hopkins' effect size (ES). Significant differences were evident between under-16 players and all senior player groups for anthropometric (p = 0.001-0.019/ES = 1.25-2.13), absolute strength (p = 0.001-0.01/ES = 1.82-4.46), and relative strength (p = 0.001-0.027/ES = 0.84-3.55). The under-18 players displayed significantly lower absolute strength (p = 0.001-0.012/ES = 1.82-3.79) and relative strength (p = 0.001-0.027/ES = 0.85-4.00) compared with the 3-7 and 8+ players. Significant differences were evident between the under-16 players and senior player groups for explosive jumping and throwing tests (p = 0.001-0.017/ES = 1.03-2.99). Minimal differences were evident between all player groups for running assessments; however, the under-16 players were significantly slower compared with the 8+ players for the 3-km time trial (p < 0.02/ES = 1.31), whereas both junior player groups covered significantly less distance during the Yo-Yo IR2 (p < 0.02/ES = 1.19 and 1.60). Results of this study display a significant deficit in strength between junior and senior AF players.

Formative Evaluation of a Massively Multi-Player Persistent (MMP) Environment for Asymmetric Warfare Exercises

DTIC Science & Technology

2008-04-01

Initiative acknowledges the dearth of published research on Massively Multiplayer Online Games ((MMOGs), which are based on MMP technology) for...wanting help during the emergency, protesting insufficient aid being delivered in time, escalating to violence , including sniper attacks and attempted... multiplayer environment. The movement control systems were rated "moderately easy" to learn, and ease of movement after learning to use the controls was rated

Games for Social Change: Review of the Potential for Multi Player Online Gaming to Facilitate the Emergence and Growth of Progressive Movements for Social Change within Youth and Community Work

ERIC Educational Resources Information Center

Keating, Paul

2016-01-01

Building on the use of the internet and social media as sites for activism, this paper highlights the emergence of political activism and collective protest in the online gaming environment. Referencing social movement theory and the rapidly evolving capacity of multiplayer online games to facilitate the development of strong group identities and…

Event-based image recognition applied in tennis training assistance

NASA Astrophysics Data System (ADS)

Wawrzyniak, Zbigniew M.; Kowalski, Adam

2016-09-01

This paper presents a concept of a real-time system for individual tennis training assistance. The system is supposed to provide user (player) with information on his strokes accuracy as well as other training quality parameters such as velocity and rotation of the ball during its flight. The method is based on image processing methods equipped with developed explorative analysis of the events and their description by parameters of the movement. There has been presented the concept for further deployment to create a complete system that could assist tennis player during individual training.

Physiologically Modulating Videogames or Simulations which use Motion-Sensing Input Devices

NASA Technical Reports Server (NTRS)

Pope, Alan T. (Inventor); Stephens, Chad L. (Inventor); Blanson, Nina Marie (Inventor)

2014-01-01

New types of controllers allow players to make inputs to a video game or simulation by moving the entire controller itself. This capability is typically accomplished using a wireless input device having accelerometers, gyroscopes, and an infrared LED tracking camera. The present invention exploits these wireless motion-sensing technologies to modulate the player's movement inputs to the videogame based upon physiological signals. Such biofeedback-modulated video games train valuable mental skills beyond eye-hand coordination. These psychophysiological training technologies enhance personal improvement, not just the diversion, of the user.

Competing with lower level opponents decreases intra-team movement synchronization and time-motion demands during pre-season soccer matches.

PubMed

Folgado, Hugo; Duarte, Ricardo; Fernandes, Orlando; Sampaio, Jaime

2014-01-01

This study aimed to quantify the time-motion demands and intra-team movement synchronization during the pre-season matches of a professional soccer team according to the opposition level. Positional data from 20 players were captured during the first half of six pre-season matches of a Portuguese first league team. Time-motion demands were measured by the total distance covered and distance covered at different speed categories. Intra-team coordination was measured by calculating the relative phase of all pairs of outfield players. Afterwards, the percentage of time spent in the -30° to 30° bin (near-in-phase mode of coordination) was calculated for each dyad as a measure of space-time movement synchronization. Movement synchronization data were analyzed for the whole team, according to each dyad average speed and by groups of similar dyadic synchronization tendencies. Then, these data were compared according to the opponent team level (first league; second league; amateurs). Time-motion demands showed no differences in total distance covered per opposition levels, while matches opposing teams of superior level revealed more distance covered at very high intensity. Competing against superior level teams implied more time in synchronized behavior for the overall displacements and displacements at higher intensities. These findings suggest that playing against higher-level opponents (1st league teams) increased time-motion demands at high intensities in tandem with intra-team movement synchronization tendencies.

Football boot insoles and sensitivity to extent of ankle inversion movement.

PubMed

Waddington, G; Adams, R

2003-04-01

The capacity of the plantar sole of the foot to convey information about foot position is reduced by conventional smooth boot insoles, compared with barefoot surface contact. To test the hypothesis that movement discrimination may be restored by inserting textured replacement insoles, achieved by changing footwear conditions and measuring the accuracy of judgments of the extent of ankle inversion movement. An automated testing device, the ankle movement extent discrimination apparatus (AMEDA), developed to assess active ankle function in weight bearing without a balance demand, was used to test the effects of sole inserts in soccer boots. Seventeen elite soccer players, the members of the 2000 Australian Women's soccer squad (34 ankles), took part in the study. Subjects were randomly allocated to start testing in: bare feet, their own football boots, own football boot and replacement insole, and on the left or right side. Subjects underwent six 50 trial blocks, in which they completed all footwear conditions. The sole inserts were cut to size for each foot from textured rubber "finger profile" sheeting. Movement discrimination scores were significantly worse when subjects wore their football boots and socks, compared with barefoot data collected at the same time. The substitution of textured insoles for conventional smooth insoles in the football boots was found to restore movement discrimination to barefoot levels. The lower active movement discrimination scores of athletes when wearing football boots with smooth insoles suggest that the insole is one aspect of football boot and sport shoe design that could be modified to provide the sensory feedback needed for accurate foot positioning.

Management of chronic recurrent osteitis pubis/pubic bone stress in a Premier League footballer: Evaluating the evidence base and application of a nine-point management strategy.

PubMed

McAleer, Stephen S; Gille, Justus; Bark, Stefan; Riepenhof, Helge

2015-08-01

The aim of this paper was to use a clinical example to describe a treatment strategy for the management of recurrent chronic groin pain and evaluate the evidence of the interventions. A professional footballer presented with chronic recurrent OP/PBS. The injury was managed successfully with a nine-point programme - 1. Acute pharmacological management. 2. Tone reduction of over-active structures. 3. Improved ROM at hips, pelvis and thorax. 4. Adductor strength. 5. Functional movement assessment. 6. Core stability. 7. Lumbo-pelvic control. 8. Gym-based strengthening. 9. Field-based conditioning/rehabilitation. The evidence for these interventions is reviewed. The player returned to full training and match play within 41 and 50 days, respectively, and experienced no recurrence of his symptoms in follow up at 13 months. This case report displays a nine-point conservative management strategy for OP/PBS, with non-time dependent clinical objective markers as the progression criteria in a Premier League football player. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biomechanical symmetry in elite rugby union players during dynamic tasks: an investigation using discrete and continuous data analysis techniques.

PubMed

Marshall, Brendan; Franklyn-Miller, Andrew; Moran, Kieran; King, Enda; Richter, Chris; Gore, Shane; Strike, Siobhán; Falvey, Éanna

2015-01-01

While measures of asymmetry may provide a means of identifying individuals predisposed to injury, normative asymmetry values for challenging sport specific movements in elite athletes are currently lacking in the literature. In addition, previous studies have typically investigated symmetry using discrete point analyses alone. This study examined biomechanical symmetry in elite rugby union players using both discrete point and continuous data analysis techniques. Twenty elite injury free international rugby union players (mean ± SD: age 20.4 ± 1.0 years; height 1.86 ± 0.08 m; mass 98.4 ± 9.9 kg) underwent biomechanical assessment. A single leg drop landing, a single leg hurdle hop, and a running cut were analysed. Peak joint angles and moments were examined in the discrete point analysis while analysis of characterising phases (ACP) techniques were used to examine the continuous data. Dominant side was compared to non-dominant side using dependent t-tests for normally distributed data or Wilcoxon signed-rank test for non-normally distributed data. The significance level was set at α = 0.05. The majority of variables were found to be symmetrical with a total of 57/60 variables displaying symmetry in the discrete point analysis and 55/60 in the ACP. The five variables that were found to be asymmetrical were hip abductor moment in the drop landing (p = 0.02), pelvis lift/drop in the drop landing (p = 0.04) and hurdle hop (p = 0.02), ankle internal rotation moment in the cut (p = 0.04) and ankle dorsiflexion angle also in the cut (p = 0.01). The ACP identified two additional asymmetries not identified in the discrete point analysis. Elite injury free rugby union players tended to exhibit bi-lateral symmetry across a range of biomechanical variables in a drop landing, hurdle hop and cut. This study provides useful normative values for inter-limb symmetry in these movement tests. When examining symmetry it is recommended to incorporate continuous data analysis techniques rather than a discrete point analysis alone; a discrete point analysis was unable to detect two of the five asymmetries identified.

The effect of model uncertainty on cooperation in sensorimotor interactions

PubMed Central

Grau-Moya, J.; Hez, E.; Pezzulo, G.; Braun, D. A.

2013-01-01

Decision-makers have been shown to rely on probabilistic models for perception and action. However, these models can be incorrect or partially wrong in which case the decision-maker has to cope with model uncertainty. Model uncertainty has recently also been shown to be an important determinant of sensorimotor behaviour in humans that can lead to risk-sensitive deviations from Bayes optimal behaviour towards worst-case or best-case outcomes. Here, we investigate the effect of model uncertainty on cooperation in sensorimotor interactions similar to the stag-hunt game, where players develop models about the other player and decide between a pay-off-dominant cooperative solution and a risk-dominant, non-cooperative solution. In simulations, we show that players who allow for optimistic deviations from their opponent model are much more likely to converge to cooperative outcomes. We also implemented this agent model in a virtual reality environment, and let human subjects play against a virtual player. In this game, subjects' pay-offs were experienced as forces opposing their movements. During the experiment, we manipulated the risk sensitivity of the computer player and observed human responses. We found not only that humans adaptively changed their level of cooperation depending on the risk sensitivity of the computer player but also that their initial play exhibited characteristic risk-sensitive biases. Our results suggest that model uncertainty is an important determinant of cooperation in two-player sensorimotor interactions. PMID:23945266

Physiological and skill demands of 'on-side' and 'off-side' games.

PubMed

Gabbett, Tim J; Jenkins, David G; Abernethy, Bruce

2010-11-01

This study investigated the physiological and skill demands of 'on-side' and 'off-side' games in elite rugby league players. Sixteen male rugby league players participated in 'on-side' and 'off-side' games. Both small-sided games were played in a 40- × 40-m playing area. The 'off-side' game permitted players to have 3 'plays' while in possession of the ball. Players were permitted to pass backward or forward (to an 'off-side' player). The 'on-side' game also permitted players to have 3 'plays' while in possession of the ball. However, players were only permitted to pass backward to players in an 'on-side' position. Heart rate and movement patterns (via global positioning system) were recorded continuously throughout both games. Data were collected on the distance covered, number of high-acceleration and velocity efforts, and recovery between efforts. Video footage was also taken to track the performance of the players. Post hoc inspection of the footage was undertaken to count the number of possessions and the number and quality of disposals. In comparison to 'on-side' games, 'off-side' games had a greater number of involvements ("touches"), passes, and effective passes. However, the cognitive demands of 'on-side' games were greater than 'off-side' games. 'Off-side' games resulted in a greater total distance covered, greater distance covered in mild and moderate accelerations, and greater distance covered in low, moderate, and high-velocity efforts. There were also a greater number of short duration recovery periods between efforts in 'off-side' games. The results of this study demonstrate that 'off-side' games provide greater physiological and skill demands than 'on-side' games. 'Off-side' games may provide a practical alternative to 'on-side' games for the development of skill and fitness in elite rugby league players.

A biomechanical investigation of right-forward lunging step among badminton players.

PubMed

Mei, Qichang; Gu, Yaodong; Fu, Fengqin; Fernandez, Justin

2017-03-01

This study presents the kinematics and plantar pressure characteristics of eight elite national-level badminton athletes and eight recreational college-level badminton players while performing a right-forward lunge movement in a laboratory-simulated badminton court. The hypothesis was that recreational players would be significantly different from elite players in kinematics and plantar pressure measures. Vicon ® motion capture and Novel ® insole plantar pressure measurement were simultaneously taken to record the lower extremity kinematics and foot loading during stance. Recreational players showed significantly higher peak pressure in the lateral forefoot (P = 0.002) and force time integral in the lateral forefoot (P = 0.013) and other toes (P = 0.005). Elite athletes showed higher peak pressure in the medial forefoot (P = 0.003), hallux (P = 0.037) and force time integral in the medial forefoot (P = 0.009). The difference in landing techniques for the lunge step between elite athletes and recreational players was observed with peak ankle eversion (-38.2°±2.4° for athletes and -11.1°±3.9° for players, P = 0.015); smaller knee range of motion in the coronal and transverse planes, with differences in peak knee adduction (28.9°±6.8° for athletes and 15.7°±6.2° for players, P = 0.031); peak knee internal rotation (20.3°±1.3° for athletes and 11.8°±3.2° for players, P = 0.029) and peak hip flexion (77.3°±4.1° for athletes and 91.3°±9.3° for players, P = 0.037).

The Prevalence of Injuries in Professional Turkish Soccer Players

ERIC Educational Resources Information Center

Yamaner, Faruk; Gumusdag, Hayrettin; Kartal, Alparslan; Gumus, M.; Gullu, A.; Imamoglu, O.

2011-01-01

Study aim: To assess the prevalence and anatomical sites of injuries in professional soccer players in one game season. Material and methods: A cohort of 510 professional male soccer players consisting of 48 goalkeepers, 194 defence players, 189 mid-field players and 79 forward players of the 1st and 2nd Turkish Professional Soccer Leagues in…

The mechanisms and boundary conditions of the Einstellung effect in chess: evidence from eye movements.

PubMed

Sheridan, Heather; Reingold, Eyal M

2013-01-01

In a wide range of problem-solving settings, the presence of a familiar solution can block the discovery of better solutions (i.e., the Einstellung effect). To investigate this effect, we monitored the eye movements of expert and novice chess players while they solved chess problems that contained a familiar move (i.e., the Einstellung move), as well as an optimal move that was located in a different region of the board. When the Einstellung move was an advantageous (but suboptimal) move, both the expert and novice chess players who chose the Einstellung move continued to look at this move throughout the trial, whereas the subset of expert players who chose the optimal move were able to gradually disengage their attention from the Einstellung move. However, when the Einstellung move was a blunder, all of the experts and the majority of the novices were able to avoid selecting the Einstellung move, and both the experts and novices gradually disengaged their attention from the Einstellung move. These findings shed light on the boundary conditions of the Einstellung effect, and provide convergent evidence for Bilalić, McLeod, & Gobet (2008)'s conclusion that the Einstellung effect operates by biasing attention towards problem features that are associated with the familiar solution rather than the optimal solution.

Increased plantar force and impulse in American football players with high arch compared to normal arch

PubMed Central

Carson, Daniel W.; Myer, Gregory D.; Hewett, Timothy E.; Heidt, Robert S.; Ford, Kevin R.

2014-01-01

Background Risk of overuse injury among athletes is high due in part to repeated loading of the lower extremities. Compared to individuals with normal arch (NA) structure, those with high (HA) or low arch (LA) may be at increased risk of specific overuse injuries, including stress fractures. A high medial longitudinal arch may result in decreased shock absorbing properties due to increased rigidity in foot mechanics. While the effect of arch structure on dynamic function has been examined in straight line walking and running, the relationship between the two during multi-directional movements remains unstudied. Objective The purpose of this study was to determine if differences in plantar loading in football players occur during both walking and pivoting movements. Method Plantar loading was examined in 9 regions of the foot for 26 participants (16 NA, 10 HA). Results High arch athletes demonstrated increased maximum force in the lateral rear foot and medial forefoot, and force time integral in the medial forefoot while walking. HA athletes also demonstrated increased maximum force in the medial rear foot and medial and central forefoot during rapid pivoting. Conclusions The current findings demonstrate that loading patterns differ between football players with high and normal arch structure, which could possibly influence injury risk in this population. PMID:23141809

Comparing performance and kinematics of throwing with a circular and whip-like wind up by experienced handball players.

PubMed

van den Tillaar, R; Zondag, A; Cabri, J

2013-12-01

The aim of this study was to compare the performance (throwing velocity of the ball) and kinematics of overarm throwing with the circular and whip-like wind up in elite handball players. Twenty-two elite handball players (11 men and 11 women) conducted both types of throws. The ball release velocity, maximal ball acceleration, maximal velocity of the end points of the five segments and maximal angles, angles at ball release and maximal angular velocities of the 11 joint movements and their timing during the throw were analyzed. Significantly higher ball release velocities (21.9 m/s vs 20.6 m/s) were reached together with higher maximal linear velocities of the end points of all segments and longer throwing time with the circular wind up than with the whip-like wind up. Furthermore, it seems that the timing and amount of maximal angular pelvis rotation was the main contributor to the difference in the maximal ball release velocity between the two wind ups. The findings support the observation that overarm throwing with the circular wind up results in higher ball releases but also a longer throwing movement in comparison to whip-like wind up throws. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Can Perceptuo-Motor Skills Assessment Outcomes in Young Table Tennis Players (7-11 years) Predict Future Competition Participation and Performance? An Observational Prospective Study.

PubMed

Faber, Irene R; Elferink-Gemser, Marije T; Faber, Niels R; Oosterveld, Frits G J; Nijhuis-Van der Sanden, Maria W G

2016-01-01

Forecasting future performance in youth table tennis players based on current performance is complex due to, among other things, differences between youth players in growth, development, maturity, context and table tennis experience. Talent development programmes might benefit from an assessment of underlying perceptuo-motor skills for table tennis, which is hypothesized to determine the players' potential concerning the perceptuo-motor domain. The Dutch perceptuo-motor skills assessment intends to measure the perceptuo-motor potential for table tennis in youth players by assessing the underlying skills crucial for developing technical and tactical qualities. Untrained perceptuo-motor tasks are used as these are suggested to represent a player's future potential better than specific sport skills themselves as the latter depend on exposure to the sport itself. This study evaluated the value of the perceptuo-motor skills assessment for a talent developmental programme by evaluating its predictive validity for competition participation and performance in 48 young table tennis players (7-11 years). Players were tested on their perceptuo-motor skills once during a regional talent day, and the subsequent competition results were recorded half-yearly over a period of 2.5 years. Logistic regression analysis showed that test scores did not predict future competition participation (p >0.05). Yet, the Generalized Estimating Equations analysis, including the test items 'aiming at target', 'throwing a ball', and 'eye-hand coordination' in the best fitting model, revealed that the outcomes of the perceptuo-motor skills assessment were significant predictors for future competition results (R2 = 51%). Since the test age influences the perceptuo-motor skills assessment's outcome, another multivariable model was proposed including test age as a covariate (R2 = 53%). This evaluation demonstrates promising prospects for the perceptuo-motor skills assessment to be included in a talent development programme. Future studies are needed to clarify the predictive value in a larger sample of youth competition players over a longer period in time.

Relationships between the yo-yo intermittent recovery test and anaerobic performance tests in adolescent handball players.

PubMed

Hermassi, Souhail; Aouadi, Ridha; Khalifa, Riadh; van den Tillaar, Roland; Shephard, Roy J; Chelly, Mohamed Souhaiel

2015-03-29

The aim of the present study was to investigate relationships between a performance index derived from the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) and other measures of physical performance and skill in handball players. The other measures considered included peak muscular power of the lower limbs (Wpeak), jumping ability (squat and counter-movement jumps (SJ, CMJ), a handball skill test and the average sprinting velocities over the first step (VS) and the first 5 m (V5m). Test scores for 25 male national-level adolescent players (age: 17.2 ± 0.7 years) averaged 4.83 ± 0.34 m·s(-1) (maximal velocity reached at the Yo-Yo IR1); 917 ± 105 Watt, 12.7 ± 3 W·kg(-1) (Wpeak); 3.41 ± 0.5 m·s(-1) and 6.03 ± 0.6 m·s(-1) (sprint velocities for Vs and V5m respectively) and 10.3 ± 1 s (handball skill test). Yo-Yo IR1 test scores showed statistically significant correlations with all of the variables examined: Wpeak (W and W·kg(-1)) r = 0.80 and 0.65, respectively, p≤0.001); sprinting velocities (r = 0.73 and 0.71 for VS and V5m respectively; p≤0.001); jumping performance (SJ: r = 0.60, p≤0.001; CMJ: r= 0.66, p≤0.001) and the handball skill test (r = 0.71; p≤0.001). We concluded that the Yo-Yo test score showed a sufficient correlation with other potential means of assessing handball players, and that intra-individual changes of Yo-Yo IR1 score could provide a useful composite index of the response to training or rehabilitation, although correlations lack sufficient precision to help in players' selection.

Difference in Functional Performance on the Upper-Quarter Y-Balance Test Between High School Baseball Players and Wrestlers.

PubMed

Myers, Heather; Poletti, Mary; Butler, Robert J

2017-05-01

The Upper Quarter Y-Balance Test (YBT-UQ) is a unique movement test where individuals perform at the limits of their stability, requiring the coordination of balance, proprioception, range of motion, and stabilization. It is not yet clear if performance on the YBT-UQ differs between sports with dissimilar emphasis on upper-extremity performance. To compare performance on the YBT-UQ between wrestlers, whose sport requires some degree of closed-chain activity, and baseball players, whose sport is primarily open kinetic chain in nature. Cross-sectional. High school preparticipation physical assessment. 24 healthy high school male wrestlers (mean age 16.12 ± 1.24 y) and 24 healthy high school male baseball players (mean age 15.79 ± 1.25 y). All subjects performed the YBT-UQ, which requires reaching in 3 directions while maintaining a push-up position. The variables of interest include the maximum reach in each direction, as well as the composite score. In addition, asymmetries between limbs for each reach direction were compared. Wrestlers performed significantly better than baseball players in the medial direction, inferolateral direction, and in composite scores. In the medial direction, wrestlers exhibited greater scores (P < .01) on both left and right limbs, 10.5 ± 10.2%LL and 9.95 ± 10.2%LL, respectively. Significant differences (P < .01) were also observed in the inferolateral direction, with a difference of 11.3 ± 12.0%LL on the left and 8.7 ± 11.0%LL on the right. Composite scores were higher (P < .01) for the wrestlers, with a difference of 7.0% on the left and 7.1% on the right. This study suggests that wrestlers perform better on the YBT-UQ than baseball players. The findings may suggest sport-specific normative data for the YBT-UQ in high school athletes.

Relationships between maximal strength of lower limb, anthropometric characteristics and fundamental explosive performance in handball players.

PubMed

Hermassi, Souhail; Chelly, Mohamed Souhaiel; Wagner, Herbert; Fieseler, Georg; Schulze, Stephan; Delank, Karl-Stefan; Shephard, Roy J; Schwesig, René

2018-02-14

 The purpose of this study was to examine relationships between lower body muscular strength, anthropometric characteristics and several measures of explosive performance in elite team-handball players.  22 male elite team-handball players (age: 19.1 ± 1.7 years) were studied during the competitive season. Standard anthropometric and body composition measures included body mass index, lower limb and thigh muscle volume, and body fat percentage. Maximal leg strength was determined by a one-repetition maximum (1-RM) half back-squat. Vertical jump performance was assessed using a squat jump (SJ) and a counter movement jump (CMJ). Repeated shuttle-sprint ability (RSA) was tested by 6 (2 × 15 m) shuttle sprints with 20 s of active recovery intervals. The best time in a single shuttle sprint (30m; RSA best ), fastest total time (RSA TT ) and RSA test performance decrement (RSA dec ) were recorded. Agility was measured using a modified T-half test (MAT). Throwing velocities of jump shooting and 3-step throwing were recorded by digital video camera.  The explained variance of 1-RM half-back-squats ranged from 0.2 % (RSA% Fatigue Index) to 70.1 % (CMJ). Four out of 8 variables (RSA Best Time, CMJ, SJ, throwing velocity of jump shoot) demonstrated an r 2  > 0.5. Jump performances seemed closely related to 1-RM half-back-squats. Furthermore, 1-RM half-back-squats were positively correlated with leg and thigh muscle volumes (r = 0.652, r = 0.768).  The anthropometric characteristics and some physical performance tests are closely related to the maximal strength performance of handball players. Coaches should focus on maximal strength training programs for the lower limbs when seeking improvements in the throwing velocity and jump performance of handball players. © Georg Thieme Verlag KG Stuttgart · New York.

Social network analysis of cattle movement in Kampong Cham, Kampong Speu and Takeo, Cambodia.

PubMed

Poolkhet, C; Kasemsuwan, S; Seng, S; Keartha, C; Sokmao, C; Shin, M; Kalpravidh, W; Hinrichs, J

2016-07-01

The aim of this study is to provide insight the network of cattle movement in Kampong Cham, Kampong Speu and Takeo, Cambodia. A cross-sectional study was carried out from July 2014 to August 2014, using questionnaires. It was implemented with 435 interviewees (24.4%, 24.6% and 51.0% from Kampong Cham, Kampong Speu and Takeo, respectively) using one-step snowball sampling. The findings suggest that the key players in all three provinces are producers who raise their cattle as backyard animals. In all three provinces the key players in spreading disease are probably the middlemen, collectors, brokers or traders. The network of cattle movement is presented as a strong component of varying size in each location. In this network we found three cut-points in both Kampong Cham and Kampong Speu. The network in each province indicates a random pattern of node distribution. The results of our study are useful to relevant authorities and researchers to understand the spread of infectious diseases into different areas. The middlemen, collectors, brokers and traders need to be controlled as first priority in order to reduce the magnitude of the spread of disease. Copyright © 2016 Elsevier B.V. All rights reserved.

The science of badminton: game characteristics, anthropometry, physiology, visual fitness and biomechanics.

PubMed

Phomsoupha, Michael; Laffaye, Guillaume

2015-04-01

Badminton is a racket sport for two or four people, with a temporal structure characterized by actions of short duration and high intensity. This sport has five events: men's and women's singles, men's and women's doubles, and mixed doubles, each requiring specific preparation in terms of technique, control and physical fitness. Badminton is one of the most popular sports in the world, with 200 million adherents. The decision to include badminton in the 1992 Olympics Game increased participation in the game. This review focuses on the game characteristics, anthropometry, physiology, visual attributes and biomechanics of badminton. Players are generally tall and lean, with an ectomesomorphic body type suited to the high physiological demands of a match. Indeed, a typical match characteristic is a rally time of 7 s and a resting time of 15 s, with an effective playing time of 31%. This sport is highly demanding, with an average heart rate (HR) of over 90% of the player's maximal HR. The intermittent actions during a game are demanding on both the aerobic and anaerobic systems: 60-70% on the aerobic system and approximately 30% on the anaerobic system, with greater demand on the alactic metabolism with respect to the lactic anaerobic metabolism. The shuttlecock has an atypical trajectory, and the players perform specific movements such as lunging and jumping, and powerful strokes using a specific pattern of movement. Lastly, badminton players are visually fit, picking up accurate visual information in a short time. Knowledge of badminton can help to improve coaching and badminton skills.

Speed and agility of 12- and 14-year-old elite male basketball players.

PubMed

Jakovljevic, Sasa T; Karalejic, Milivoje S; Pajic, Zoran B; Macura, Marija M; Erculj, Frane F

2012-09-01

The aims of this study were (a) to identify and compare the speed and agility of 12- and 14-year-old elite male basketball players and (b) to investigate relations between speed and agility for both age groups of basketball players, to help coaches to improve their work. Sixty-four players aged 12 (M = 11.98 years, SD = 0.311) and 54 players aged 14 (M = 14.092 years, SD = 0.275) were tested. Three agility tests: agility t-test, zigzag agility drill, and agility run 4 × 15 m and 3 speed tests: 20-m run, 30-m run, and 50-m run were applied. Fourteen-year-old players achieved significantly better results in all speed and agility tests compared with 12-year-old players. The correlation coefficient (r = 0.81, p = 0.001) showed that 12-year-old players have the same ability in the 30- and 50-m runs. The other correlation coefficient (r = 0.59, p = 0.001) indicated that 20- and 30-m runs had inherently different qualities. The correlation coefficients between agility tests were <0.71, and therefore, each test in this group represents a specific task. In 14-year-old players, the correlation coefficients between the speed test results were <0.71. In contrast, the correlation coefficients between the agility tests were >0.71, which means that all the 3 tests represent the same quality. During the speed training of 12-year-old players, it is advisable to focus on shorter running distances, up to 30 m. During the agility training of the same players, it is useful to apply exercises with various complexities. In speed training of the 14-year-old players, the 30- and 50-m runs should be applied, and agility training should include more specific basketball movements and activities.

Match analysis and player characteristics in rugby sevens.

PubMed

Ross, Alex; Gill, Nicholas; Cronin, John

2014-03-01

Rugby sevens is a contact sport contested by two teams of seven players who compete over two 7-min halves, most frequently played in a tournament style. The IRB Sevens World Series is thought of as the preeminent rugby sevens competition in the world and has grown in competitiveness from its inception in 2000. The decision to include rugby sevens in the 2016 Olympics is likely to increase the global profile and participation in the game. Many rugby sevens players concurrently compete in 15-a-side rugby union as backs and loose forwards; however, a continued increase in the popularity of rugby sevens will likely see the emergence of the specialist rugby sevens player. Often thought of as the abbreviated version of rugby union, rugby sevens is played under nearly identical laws and on the same field dimensions as the 15-man code. However, research has shown the movement demands of rugby sevens and rugby union are dissimilar, with rugby sevens players spending a larger proportion of the game running at high intensity (≥ 5 m s(-1)). Given the dissimilarity in match demands in conjunction with differences in the competition structure between the codes, it appears the considerable depth of literature specific to performance in rugby union may be of little value for the preparation of rugby sevens players. Investigations of the physical characteristics of rugby sevens players show backs are lighter and shorter than forwards, while players across all positions possess a lean body composition. International rugby sevens players have similar speed characteristics to rugby union backs across distances of 10-30 m; however, rugby sevens players appear to have superior intermittent aerobic endurance. Despite being of likely importance, little is known of the strength and power characteristics of rugby sevens players. Research into the speed and aerobic endurance characteristics of rugby sevens players has not distinguished between backs and forwards and, as such, it is unclear whether differences exist between the position groups.

Comparison of In-Season-Specific Resistance vs. A Regular Throwing Training Program on Throwing Velocity, Anthropometry, and Power Performance in Elite Handball Players.

PubMed

Hermassi, Souhail; van den Tillaar, Roland; Khlifa, Riadh; Chelly, Mohamed Souhaiel; Chamari, Karim

2015-08-01

The purpose of this study was to compare the effect of a specific resistance training program (throwing movement with a medicine ball) with that of regular training (throwing with regular balls) on ball velocity, anthropometry, maximal upper-body strength, and power. Thirty-four elite male team handball players (age: 18 ± 0.5 years, body mass: 80.6 ± 5.5 kg, height: 1.80 ± 5.1 m, body fat: 13.4 ± 0.6%) were randomly assigned to 1 of the 3 groups: control (n = 10), resistance training group (n = 12), or regular throwing training group (n = 12). Over the 8-week in season, the athletes performed 3 times per week according to an assigned training program alongside their normal team handball training. One repetition maximum (1RM) bench press and 1RM pullover scores assessed maximal arm strength. Anthropometry was assessed by body mass, fat percentage, and muscle volumes of upper body. Handball throwing velocity was measured by a standing throw, a throw with run, and a jump throw. Power was measured by measuring total distance thrown by a 3-kg medicine ball overhead throw. Throwing ball velocity, maximal strength, power, and muscle volume increases for the specific resistance training group after the 8 weeks of training, whereas only maximal strength, muscle volume and power and in the jump throw increases were found for the regular throwing training group. No significant changes for the control group were found. The current findings suggest that elite male handball players can improve ball velocity, anthropometrics, maximal upper-body strength, and power during the competition season by implementing a medicine ball throwing program.

Enhancing the learning of sport skills through external-focus feedback.

PubMed

Wulf, Gabriele; McConnel, Nathan; Gärtner, Matthias; Schwarz, Andreas

2002-06-01

The authors examined how the effectiveness of feedback for the learning of complex motor skills is affected by the focus of attention it induces. The feedback referred specifically either to body movements (internal focus) or to movement effects (external focus). In Experiment 1, groups of novices and advanced volleyball players (N = 48) practiced "tennis" serves under internal-focus or external-focus feedback conditions in a 2 (expertise) x 2 (feedback type) design. Type of feedback did not differentially affect movement quality, but external-focus feedback resulted in greater accuracy of the serves than internal-focus feedback during both practice and retention, independent of the level of expertise. In Experiment 2, the effects of relative feedback frequency as a function of attentional focus were examined. A 2 (feedback frequency: 100% vs. 33%) x 2 (feedback type) design was used. Experienced soccer players (N = 52) were required to shoot lofted passes at a target. External-focus feedback resulted in greater accuracy than internal-focus feedback did. In addition, reduced feedback frequency was beneficial under internal-focus feedback conditions, whereas 100% and 33% feedback were equally effective under external-focus conditions. The results demonstrate the effectiveness of effect-related, as opposed to movement-related, feedback and also suggest that there is a need to revise current views regarding the role of feedback for motor learning.

Player Monitoring in Indoor Team Sports: Concurrent Validity of Inertial Measurement Units to Quantify Average and Peak Acceleration Values

PubMed Central

Roell, Mareike; Roecker, Kai; Gehring, Dominic; Mahler, Hubert; Gollhofer, Albert

2018-01-01

The increasing interest in assessing physical demands in team sports has led to the development of multiple sports related monitoring systems. Due to technical limitations, these systems primarily could be applied to outdoor sports, whereas an equivalent indoor locomotion analysis is not established yet. Technological development of inertial measurement units (IMU) broadens the possibilities for player monitoring and enables the quantification of locomotor movements in indoor environments. The aim of the current study was to validate an IMU measuring by determining average and peak human acceleration under indoor conditions in team sport specific movements. Data of a single wearable tracking device including an IMU (Optimeye S5, Catapult Sports, Melbourne, Australia) were compared to the results of a 3D motion analysis (MA) system (Vicon Motion Systems, Oxford, UK) during selected standardized movement simulations in an indoor laboratory (n = 56). A low-pass filtering method for gravity correction (LF) and two sensor fusion algorithms for orientation estimation [Complementary Filter (CF), Kalman-Filter (KF)] were implemented and compared with MA system data. Significant differences (p < 0.05) were found between LF and MA data but not between sensor fusion algorithms and MA. Higher precision and lower relative errors were found for CF (RMSE = 0.05; CV = 2.6%) and KF (RMSE = 0.15; CV = 3.8%) both compared to the LF method (RMSE = 1.14; CV = 47.6%) regarding the magnitude of the resulting vector and strongly emphasize the implementation of orientation estimation to accurately describe human acceleration. Comparing both sensor fusion algorithms, CF revealed slightly lower errors than KF and additionally provided valuable information about positive and negative acceleration values in all three movement planes with moderate to good validity (CV = 3.9 – 17.8%). Compared to x- and y-axis superior results were found for the z-axis. These findings demonstrate that IMU-based wearable tracking devices can successfully be applied for athlete monitoring in indoor team sports and provide potential to accurately quantify accelerations and decelerations in all three orthogonal axes with acceptable validity. An increase in accuracy taking magnetometers in account should be specifically pursued by future research. PMID:29535641

Considerations in the Diagnosis and Accelerated Return to Sport of a Professional Basketball Player With a Triceps Surae Injury: A Case Report.

PubMed

Anloague, Philip A; Strack, Donald S

2018-05-01

Study Design Case report. Background Acute injuries of the triceps surae and Achilles tendon are common in sports. Rupture of the plantaris tendon can be challenging to diagnose. There is limited evidence detailing the diagnosis, rehabilitation, and accelerated return to sport of elite professional basketball players who have sustained calf injuries. Case Description A 25-year-old male professional basketball player sustained an injury to his calf during a professional basketball game. This case report details the presumptive diagnosis, graduated progression of intervention, and return to play of a professional athlete with a likely isolated plantaris tendon tear. Outcomes The patient returned to postseason competition 10 days post injury. Objective measures were tracked throughout rehabilitation and compared to baseline assessments. Before returning to play, the athlete showed improvements beyond the minimal clinically important difference for calf girth (2 cm) and numeric pain-rating scale score (4 points, 0-10 scale). Functional testing was conducted that included the Y Balance Test lower quarter and the Functional Movement Screen, with results that exceeded or returned the athlete to preseason levels. Discussion This report details the case of a professional basketball player who returned to competitive play in an accelerated time frame following injury to his calf. Diagnosing a plantaris tendon rupture can be challenging, and anatomical variations of this muscle should be considered. It was demonstrated in this case that physical therapy rehabilitation was helpful in making a treatment-based clinical diagnosis when imaging was unclear. Level of Evidence Therapy, level 5. J Orthop Sports Phys Ther 2018;48(5):388-397. Epub 6 Apr 2018. doi:10.2519/jospt.2018.7192.

Nonoperative Management, Rehabilitation, and Functional and Clinical Progression of Osteitis Pubis/Pubic Bone Stress in Professional Soccer Players: A Case Series.

PubMed

McAleer, Stephen S; Lippie, Ed; Norman, Darcy; Riepenhof, Helge

2017-09-01

Study Design Case series. Background Pubic bone stress (PBS) is a common acute or chronic response of the pelvis in sports where sprinting, kicking, twisting, and cutting are the dominant movements. There are few nonoperative rehabilitation strategies for the condition reported in the literature, and the outcome of conservative treatment has not been documented. Case Description Five professional and academy soccer players complaining of pubic symphysis pain, confirmed as PBS on magnetic resonance imaging and objective assessment, were treated with a nonoperative rehabilitation program that featured functional and clinical objective markers as progression criteria. Interventions in the acute phase included pharmacological and physical therapeutic modalities to reduce pain initially. Rehabilitation management focused on improving range of motion at the hips and thorax, adductor strengthening, trunk and lumbopelvic stability, gym-based strength training, and field-based rehabilitation and conditioning. Clinical follow-up was performed at least 8 months following return to play. Outcomes All players demonstrated reduced or resolved pain, increased adductor squeeze strength, and return to pain-free training and match play. Return-to-training time averaged 40.6 days (range, 30-60 days) and return to play averaged 49.4 days (range, 38-72 days) within the 5 players. At final follow-up (mean, 29.6 months; range, 16-33 months), there had been no recurrences. Discussion This report of 5 cases suggests that a nonoperative protocol, using clinical and functional progression criteria, may be successful in rehabilitating athletes with PBS for return to sport within 11 weeks. Level of Evidence Therapy, level 4. J Orthop Sports Phys Ther 2017;47(9):683-690. Epub 3 Aug 2017. doi:10.2519/jospt.2017.7314.

Detecting method of subjects' 3D positions and experimental advanced camera control system

NASA Astrophysics Data System (ADS)

Kato, Daiichiro; Abe, Kazuo; Ishikawa, Akio; Yamada, Mitsuho; Suzuki, Takahito; Kuwashima, Shigesumi

1997-04-01

Steady progress is being made in the development of an intelligent robot camera capable of automatically shooting pictures with a powerful sense of reality or tracking objects whose shooting requires advanced techniques. Currently, only experienced broadcasting cameramen can provide these pictures.TO develop an intelligent robot camera with these abilities, we need to clearly understand how a broadcasting cameraman assesses his shooting situation and how his camera is moved during shooting. We use a real- time analyzer to study a cameraman's work and his gaze movements at studios and during sports broadcasts. This time, we have developed a detecting method of subjects' 3D positions and an experimental camera control system to help us further understand the movements required for an intelligent robot camera. The features are as follows: (1) Two sensor cameras shoot a moving subject and detect colors, producing its 3D coordinates. (2) Capable of driving a camera based on camera movement data obtained by a real-time analyzer. 'Moving shoot' is the name we have given to the object position detection technology on which this system is based. We used it in a soccer game, producing computer graphics showing how players moved. These results will also be reported.

An Expressive Bodily Movement Repertoire for Marimba Performance, Revealed through Observers' Laban Effort-Shape Analyses, and Allied Musical Features: Two Case Studies

PubMed Central

Broughton, Mary C.; Davidson, Jane W.

2016-01-01

Musicians' expressive bodily movements can influence observers' perception of performance. Furthermore, individual differences in observers' music and motor expertise can shape how they perceive and respond to music performance. However, few studies have investigated the bodily movements that different observers of music performance perceive as expressive, in order to understand how they might relate to the music being produced, and the particular instrument type. In this paper, we focus on marimba performance through two case studies—one solo and one collaborative context. This study aims to investigate the existence of a core repertoire of marimba performance expressive bodily movements, identify key music-related features associated with the core repertoire, and explore how observers' perception of expressive bodily movements might vary according to individual differences in their music and motor expertise. Of the six professional musicians who observed and analyzed the marimba performances, three were percussionists and experienced marimba players. Following training, observers implemented the Laban effort-shape movement analysis system to analyze marimba players' bodily movements that they perceived as expressive in audio-visual recordings of performance. Observations that were agreed by all participants as being the same type of action at the same location in the performance recording were examined in each case study, then across the two studies. A small repertoire of bodily movements emerged that the observers perceived as being expressive. Movements were primarily allied to elements of the music structure, technique, and expressive interpretation, however, these elements appeared to be interactive. A type of body sway movement and more localized sound generating actions were perceived as expressive. These movements co-occurred and also appeared separately. Individual participant data revealed slightly more variety in the types and locations of actions observed, with judges revealing preferences for observing particular types of expressive bodily movements. The particular expressive bodily movements that are produced and perceived in marimba performance appear to be shaped by music-related and sound generating features, musical context, and observer music and motor expertise. With an understanding of bodily movements that are generated and perceived as expressive, embodied music performance training programs might be developed to enhance expressive performer-audience communication. PMID:27630585

An Expressive Bodily Movement Repertoire for Marimba Performance, Revealed through Observers' Laban Effort-Shape Analyses, and Allied Musical Features: Two Case Studies.

PubMed

Broughton, Mary C; Davidson, Jane W

2016-01-01

Musicians' expressive bodily movements can influence observers' perception of performance. Furthermore, individual differences in observers' music and motor expertise can shape how they perceive and respond to music performance. However, few studies have investigated the bodily movements that different observers of music performance perceive as expressive, in order to understand how they might relate to the music being produced, and the particular instrument type. In this paper, we focus on marimba performance through two case studies-one solo and one collaborative context. This study aims to investigate the existence of a core repertoire of marimba performance expressive bodily movements, identify key music-related features associated with the core repertoire, and explore how observers' perception of expressive bodily movements might vary according to individual differences in their music and motor expertise. Of the six professional musicians who observed and analyzed the marimba performances, three were percussionists and experienced marimba players. Following training, observers implemented the Laban effort-shape movement analysis system to analyze marimba players' bodily movements that they perceived as expressive in audio-visual recordings of performance. Observations that were agreed by all participants as being the same type of action at the same location in the performance recording were examined in each case study, then across the two studies. A small repertoire of bodily movements emerged that the observers perceived as being expressive. Movements were primarily allied to elements of the music structure, technique, and expressive interpretation, however, these elements appeared to be interactive. A type of body sway movement and more localized sound generating actions were perceived as expressive. These movements co-occurred and also appeared separately. Individual participant data revealed slightly more variety in the types and locations of actions observed, with judges revealing preferences for observing particular types of expressive bodily movements. The particular expressive bodily movements that are produced and perceived in marimba performance appear to be shaped by music-related and sound generating features, musical context, and observer music and motor expertise. With an understanding of bodily movements that are generated and perceived as expressive, embodied music performance training programs might be developed to enhance expressive performer-audience communication.

The Youth Throwing Score: Validating Injury Assessment in Young Baseball Players.

PubMed

Ahmad, Christopher S; Padaki, Ajay S; Noticewala, Manish S; Makhni, Eric C; Popkin, Charles A

2017-02-01

Epidemic levels of shoulder and elbow injuries have been reported recently in youth and adolescent baseball players. Despite the concerning frequency of these injuries, no instrument has been validated to assess upper extremity injury in this patient population. Purpose/Hypothesis: The purpose of this study was to validate an upper extremity assessment tool specifically designed for young baseball players. We hypothesized that this tool will be both reliable and valid. Cohort study (diagnosis); Level of evidence, 2. The Youth Throwing Score (YTS) was constructed by an interdisciplinary team of providers and coaches as a tool to assess upper extremity injury in youth and adolescent baseball players (age range, 10-18 years). The psychometric properties of the test were then determined. A total of 223 players completed the final survey. The players' mean age was 14.3 ± 2.7 years. Pilot analysis showed that none of the 14 questions received a mean athlete importance rating less than 3 of 5, and the final survey read at a Flesch-Kincaid level of 4.1, which is appropriate for patients aged 9 years and older. The players self-assigned their injury status, resulting in a mean instrument score of 59.7 ± 8.4 for the 148 players "playing without pain," 42.0 ± 11.5 for the 60 players "playing with pain," and 40.4 ± 10.5 for the 15 players "not playing due to pain." Players playing without pain scored significantly higher than those playing with pain and those not playing due to pain ( P < .001). Psychometric analysis showed a test-retest intraclass correlation coefficient of 0.90 and a Cronbach alpha intra-item reliability coefficient of 0.93, indicating excellent reliability and internal consistency. Pearson correlation coefficients of 0.65, 0.62, and 0.31 were calculated between the YTS and the Pediatric Outcomes Data Collection Instrument sports/physical functioning module, the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow score, and the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, respectively. Injured players scored a mean of 9.4 points higher after treatment ( P < .001), and players who improved in their self-assigned pain categorization scored 16.5 points higher ( P < .001). The YTS is the first valid and reliable instrument for assessing young baseball players' upper extremity health.

Anthropometric characteristics and motor skills in talent selection and development in indoor soccer.

PubMed

Ré, Alessandro H Nicolai; Corrêa, Umberto César; Böhme, Maria Tereza S

2010-06-01

Kick performance, anthropometric characteristics, slalom, and linear running were assessed in 49 (24 elite, 25 nonelite) postpubertal indoor soccer players in order to (a) verify whether anthropometric characteristics and physical and technical capacities can distinguish players of different competitive levels, (b) compare the kicking kinematics of these groups, with and without a defined target, and (c) compare results on the assessments and coaches' subjective rankings of the players. Thigh circumference and specific technical capacities differentiated the players by level of play; cluster analysis correctly classified 77.5% of the players. The correlation between players' standardized measures and the coaches' rankings was 0.29. Anthropometric characteristics and physical capacities do not necessarily differentiate players at post-pubertal stages and should not be overvalued during early development. Considering the coaches' rankings, performance measures outside the specific game conditions may not be useful in identification of talented players.

Adaptive Alterations in Shoulder Range of Motion and Strength in Young Tennis Players

PubMed Central

Gillet, Benoit; Begon, Mickaël; Sevrez, Violaine; Berger-Vachon, Christian; Rogowski, Isabelle

2017-01-01

Context: Playing tennis requires unilateral and intensive movement of the upper limb, which may lead to functional adaptations of the shoulder and an increased injury risk. Identifying which athletes will be future elite tennis players starts at 5 to 6 years of age. Therefore, highly skilled players practice intensively in their childhood. However, whether these functional changes occur during the prepubertal years has not been established. Objectives: To assess changes in glenohumeral-joint–rotation range of motion and strength of the shoulder-complex muscles in prepubertal elite tennis players. Design: Cross-sectional study. Setting: Tennis training sports facilities. Patients or Other Participants: Sixty-seven male tennis players (age range = 7–13 years) selected by a regional tennis center of excellence were divided into 3 biological age groups relative to their predicted age at peak height velocity: greater than 4 (n = 26; age = 8.7 ± 0.7 years, height = 132.4 ± 12.9 cm, mass = 27.8 ± 3.8 kg), 3 to 4 (n = 21; age = 10.3 ± 0.6 years, height = 144.9 ± 5.7 cm, mass = 34.7 ± 4.0 kg), and 2 (n = 20; age = 12.8 ± 1.4 years, height = 158.5 ± 8.7 cm, mass = 43.0 ± 8.2 kg) years before their age at peak height velocity. Main Outcome Measures(s): We measured the internal- and external-rotation ranges of motion of the glenohumeral joint using a goniometer and calculated the total arc of motion. Maximal isometric strength of 8 shoulder muscles was measured using a handheld dynamometer. Strength values were normalized to body weight and used to calculate 4 agonist-to-antagonist strength ratios. Results: The total arc of motion of the glenohumeral joint decreased gradually with biological age (P ≤ .01) due to the decrease in internal-rotation range of motion (P < .001). Absolute strength increased gradually with biological age (P < .001), but the relative strengths and ratios remained similar. Conclusions: Functional adaptations of the shoulder seen in adolescent and adult tennis players were observed in healthy prepubertal players. This knowledge could help clinicians and coaches more effectively monitor shoulder adaptations to tennis practice during the prepubertal years. PMID:28145740

Dynamics of tactical behaviour in association football when manipulating players' space of interaction.

PubMed

Ric, Angel; Torrents, Carlota; Gonçalves, Bruno; Torres-Ronda, Lorena; Sampaio, Jaime; Hristovski, Robert

2017-01-01

The analysis of positional data in association football allows the spatial distribution of players during matches to be described in order to improve the understanding of tactical-related constraints on the behavioural dynamics of players. The aim of this study was to identify how players' spatial restrictions affected the exploratory tactical behaviour and constrained the perceptual-motor workspace of players in possession of the ball, as well as inter-player passing interactions. Nineteen professional outfield male players were divided into two teams of 10 and 9 players, respectively. The game was played under three spatial constraints: a) players were not allowed to move out of their allocated zones, except for the player in possession of the ball; b) players were allowed to move to an adjacent zone, and; c) non-specific spatial constraints. Positional data was captured using a 5 Hz interpolated GPS tracking system and used to define the configuration states of players for each second in time. The configuration state comprised 37 categories derived from tactical actions, distance from the nearest opponent, distance from the target and movement speed. Notational analysis of players in possession of the ball allowed the mean time of ball possession and the probabilities of passing the ball between players to be calculated. The results revealed that the players' long-term exploratory behaviour decreased and their short-term exploration increased when restricting their space of interaction. Relaxing players' positional constraints seemed to increase the speed of ball flow dynamics. Allowing players to move to an adjacent sub-area increased the probabilities of interaction with the full-back during play build-up. The instability of the coordinative state defined by being free from opponents when players had the ball possession was an invariant feature under all three task constraints. By allowing players to move to adjacent sub-areas, the coordinative state became highly unstable when the distance from the target decreased. Ball location relative to the scoring zone and interpersonal distance constitute key environmental information that constrains the players' coordinative behaviour. Based on our results, dynamic overlap is presented as a good option to capture tactical performance. Moreover, the selected collective (i.e. relational) variables would allow coaches to identify the effects of training drills on teams and players' behaviour. More research is needed considering these type variables to understand how the manipulation of constraints induce a more stable or flexible dynamical structure of tactical behaviour.

Effects of Peer-Assessed Feedback, Goal Setting and a Group Contingency on Performance and Learning by 10-12-Year-Old Academy Soccer Players

ERIC Educational Resources Information Center

Holt, Josh E.; Kinchin, Gary; Clarke, Gill

2012-01-01

Background: Coaches developing young talent in team sports must maximise practice and learning of essential game skills and accurately and continuously assess the performance and potential of each player. Relative age effects highlight an erroneous process of initial and on-going player assessment, based largely on subjective opinions of game…

Effect of Leg Dominance on The Center-of-Mass Kinematics During an Inside-of-the-Foot Kick in Amateur Soccer Players.

PubMed

Zago, Matteo; Motta, Andrea Francesco; Mapelli, Andrea; Annoni, Isabella; Galvani, Christel; Sforza, Chiarella

2014-09-29

Soccer kicking kinematics has received wide interest in literature. However, while the instep-kick has been broadly studied, only few researchers investigated the inside-of-the-foot kick, which is one of the most frequently performed techniques during games. In particular, little knowledge is available about differences in kinematics when kicking with the preferred and non-preferred leg. A motion analysis system recorded the three-dimensional coordinates of reflective markers placed upon the body of nine amateur soccer players (23.0 ± 2.1 years, BMI 22.2 ± 2.6 kg/m2), who performed 30 pass-kicks each, 15 with the preferred and 15 with the non-preferred leg. We investigated skill kinematics while maintaining a perspective on the complete picture of movement, looking for laterality related differences. The main focus was laid on: anatomical angles, contribution of upper limbs in kick biomechanics, kinematics of the body Center of Mass (CoM), which describes the whole body movement and is related to balance and stability. When kicking with the preferred leg, CoM displacement during the ground-support phase was 13% higher (p<0.001), normalized CoM height was 1.3% lower (p<0.001) and CoM velocity 10% higher (p<0.01); foot and shank velocities were about 5% higher (p<0.01); arms were more abducted (p<0.01); shoulders were rotated more towards the target (p<0.01, 6° mean orientation difference). We concluded that differences in motor control between preferred and non-preferred leg kicks exist, particularly in the movement velocity and upper body kinematics. Coaches can use these results to provide effective instructions to players in the learning process, moving their focus on kicking speed and upper body behavior.

The efficacy of a movement control exercise programme to reduce injuries in youth rugby: a cluster randomised controlled trial

PubMed Central

Hislop, M D; Stokes, K A; Williams, S; McKay, C D; England, M; Kemp, S P T

2016-01-01

Background Injuries to youth rugby players have become an increasingly prominent health concern, highlighting the importance of developing and implementing appropriate preventive strategies. A growing body of evidence from other youth sports has demonstrated the efficacy of targeted exercise regimens to reduce injury risk. However, studies have yet to investigate the effect of such interventions in youth contact sport populations like rugby union. Objective To determine the efficacy of an evidence-based movement control exercise programme compared with a sham exercise programme to reduce injury risk in youth rugby players. Exercise programme compliance between trial arms and the effect of coach attitudes on compliance will also be evaluated. Setting School rugby coaches in England will be the target of the researcher intervention, with the effects of the injury prevention programmes being measured in male youth players aged 14–18 years in school rugby programmes over the 2015–2016 school winter term. Methods A cluster-randomised controlled trial with schools randomly allocated to either a movement control exercise programme or a sham exercise programme, both of which are coach-delivered. Injury measures will derive from field-based injury surveillance, with match and training exposure and compliance recorded. A questionnaire will be used to evaluate coach attitudes, knowledge, beliefs and behaviours both prior to and on the conclusion of the study period. Outcome measures Summary injury measures (incidence, severity and burden) will be compared between trial arms, as will the influence of coach attitudes on compliance and injury burden. Additionally, changes in these outcomes through using the exercise programmes will be evaluated. Trial registration number ISRTCNN13422001. PMID:27900148

Performance on the Functional Movement Screen Is Related to Hop Performance But Not to Hip and Knee Strength in Collegiate Football Players.

PubMed

Willigenburg, Nienke; Hewett, Timothy E

2017-03-01

To define the relationship between Functional Movement Screen (FMS) scores and hop performance, hip strength, and knee strength in collegiate football players. Cross-sectional cohort. Freshmen of a Division I collegiate American football team (n = 59). The athletes performed the FMS, and also a variety of hop tests, isokinetic knee strength, and isometric hip strength tasks. We recorded total FMS score, peak strength, and hop performance, and we calculated asymmetries between legs on the different tasks. Spearman correlation coefficients quantified the relationships between these measures, and χ analyses compared the number of athletes with asymmetries on the different tasks. We observed significant correlations (r = 0.38-0.56, P ≤ 0.02) between FMS scores and hop distance but not between FMS scores and hip or knee strength (all P ≥ 0.21). The amount of asymmetry on the FMS test was significantly correlated to the amount of asymmetry on the timed 6-m hop (r = 0.44, P < 0.01) but not to hip or knee strength asymmetries between limbs (all P ≥ 0.34). Functional Movement Screen score was positively correlated to hop distance, and limb asymmetry in FMS tasks was correlated to limb asymmetry in 6-m hop time in football players. No significant correlations were observed between FMS score and hip and knee strength or between FMS asymmetry and asymmetries in hip and knee strength between limbs. These results indicate that a simple hop for distance test may be a time-efficient and cost-efficient alternative to FMS testing in athletes and that functional asymmetries between limbs do not coincide with strength asymmetries.

Movement Demands and Running Intensities of Semi-Professional Rugby League Players during A 9’s Tournament: A Case Study

PubMed Central

Inglis, Paul; Bird, Stephen P.

2017-01-01

The objective of the study was to describe the movement demands and running intensities of semi-professional rugby league players during a rugby league 9’s (RL9’s) tournament. Six semi-professional rugby league players competed in a RL9’s tournament over a two-day period comprising of six games. Movement demands and running intensities were recorded using Global Positioning System (GPS) devices providing data on distance and speeds. Data is presented as mean (95% Confidence Intervals) with changes (≥ 75%) likely to exceed the smallest worthwhile change (0.2) considered practically important. Outside backs performed significantly (p < 0.05) more relative VHSR (3.9 m [3.5-4.3] vs 2.4 m [2.1-2.8]) absolute (97.7 m [81.3-114.1] vs 22.6m [15.8-29.3]) and relative (5.0 m·min-1 [4.2-5.9] vs 1.2 m·min-1 [0.8-1.6]) sprint distance than the forwards. Outside backs also performed significantly (p < 0.05) more absolute (97.7 m [81.3-114.1] vs 43.9 m [27.2-60.7]) and relative (5.0 m·min-1 [4.2-5.9] vs 2.3 m·min-1 [1.4-3.2]) sprint distance than the adjustables. Moderate (0.6 – 1.2) to very large (> 2.0) decreases in performance variables were observed over the two days. The biggest magnitude of change over the two days was seen with very large decreases in relative HSR (- 2.10) and sprint (- 2.14) distance. Between playing groups, the outside backs had the biggest decrease in running intensity with a very large (- 2.32) significant (p < 0.05) decrease in VHSR on day 2 (3.3 m·min-1 [2.5 – 4.1]) compared to day 1 (4.9 m·min-1 [4.4 – 5.4]). Running intensities are decreased during an intensified RL9’s tournament in semi-professional rugby league players. The observed decreases in running performances between playing groups are in agreement with previous research and may support the use of individualized player monitoring and recovery management during a RL9’s tournament-style competition. Key points Running intensities are decreased during an intensified rugby league 9’s tournament in semi-professional rugby league players. Forwards and backs performed significantly less high-intensity sprint efforts on day two than day one of the tournament. Appropriate planning and implementation of recovery strategies between games may reduce the potential effects of residual fatigue. PMID:28344447

The incidence and distribution of stress fractures in elite tennis players

PubMed Central

Maquirriain, J; Ghisi, J P

2006-01-01

Background Modern professional tennis involves powerful movements repeatedly subjecting the musculoskeletal system to heavy mechanical load. Thus tennis players are exposed to high risk of overuse injuries including stress fractures. Objective To determine the incidence and distribution of stress fractures in elite tennis players. Study design Retrospective cohort study. Methods The cohort study population consisted of 139 elite players (mean (SD) age, 20.0 (5.0) years; 48 female, 91 male). Stress fractures were identified and confirmed radiologically from medical records during a two year period. Injuries were analysed according to age, sex, site, severity, delay in diagnosis, and time needed to return to sports. Results 15 players sustained 18 stress fractures, corresponding to an overall case incidence of 12.9% (95% confidence interval (CI), 8.1 to 20.0). The tarsal navicular was most affected (n = 5; 27%), followed by the pars interarticularis (n = 3; 16%), the metatarsals (n = 3; 16%), the tibia (n = 2; 11%) and the lunate (n = 2; 11%). Magnetic resonance imaging showed a greater incidence of “high grade” lesions (94.4%). Stress fracture incidence was significantly higher in juniors (20.3% (95% CI, 11.4 to 33.2)) than in professional players (7.5% (2.8 to 15.6)) (p = 0.045). Conclusions There was a high absolute risk (12.9%) of stress fractures in elite tennis players over a two year period. Junior players were at highest risk. The lesions are a major cause of disruption both of training and of competition. Risk factors should therefore be identified and prevention emphasised. PMID:16632579

Parasocial interaction with my avatar: effects of interdependent self-construal and the mediating role of self-presence in an avatar-based console game, Wii.

PubMed

Jin, Seung-A Annie; Park, Namkee

2009-12-01

The "self" concept has grown increasingly important in interactive media environments. This study investigated self-related processes in an avatar-based game console, Wii. A key feature of the Wii is its motion-sensing capability that empowers players to manipulate and interact with items on-screen via movement. The present study examined the effects of video game players' self-construal on parasocial interaction with their avatars and feelings of self-presence. In this study, parasocial interaction was operationally defined as the extent of game players' interpersonal involvement with their avatar and the extent to which game players perceive themselves as interacting with the avatar. Self-presence was defined as the degree to which video game players feel as if their avatar on the screen were their real self. Based on an experiment, the study discovered that game players with high interdependent self-construal showed closer parasocial interaction and higher level of self-presence than those with low interdependent self-construal. Results also showed that self-presence mediated the effects of interdependent self-construal on the parasocial relationship with game players' avatars. Thus, the study discovered an important individual difference factor, interdependent self-construal, affecting the degree to which people form a parasocial relationship with their virtual self that is visually manifested in the form of an avatar. In addition, the present study added empirical evidence about the mediating role played by self-presence in avatar-based video games.

[Isokinetic profile of knee flexors and extensors in a population of rugby players].

PubMed

Larrat, E; Kemoun, G; Carette, P; Teffaha, D; Dugue, B

2007-06-01

We aimed to assess the isokinetic profile of the flexor and extensor muscles of the knee within a population of rugby players. This was a descriptive study. The rugby players underwent bilateral isokinetic assessment of knee flexion and extension on a CON-TREX MJ isokinetic dynamometer functioning at four angular frequencies - 90, 120, 180 and 240 degrees/s - in a concentric manner. The isokinetic parameters were peak torque, mean power, and mean work in relation to weight and femoral bicep: quadriceps ratio. The population included 16 "Federal 1" (semi-professional) rugby players with mean age 25 years (range 20-33 years). The players were divided into two groups: "forward" players (props, hookers, second line, third line) and "back" players (scrum, inside, center, wing, tail). The values of the isokinetic parameters did not reveal use of a preferred limb. Consequently, peak torque and mean power were higher in forward players than back players, whereas back players showed a higher relative power throughout the isokinetic test. Among rugby players, forward and back players showed differences in several isokinetic parameters. Accurate knowledge of the equilibrium between the knee's effector muscles is important for stability of the joint, to not only minimize articular accidents but also pinpoint force imbalances, thereby preventing muscular lesions during the sports season.

Collision count in rugby union: A comparison of micro-technology and video analysis methods.

PubMed

Reardon, Cillian; Tobin, Daniel P; Tierney, Peter; Delahunt, Eamonn

2017-10-01

The aim of our study was to determine if there is a role for manipulation of g force thresholds acquired via micro-technology for accurately detecting collisions in rugby union. In total, 36 players were recruited from an elite Guinness Pro12 rugby union team. Player movement profiles and collisions were acquired via individual global positioning system (GPS) micro-technology units. Players were assigned to a sub-category of positions in order to determine positional collision demands. The coding of collisions by micro-technology at g force thresholds between 2 and 5.5 g (0.5 g increments) was compared with collision coding by an expert video analyst using Bland-Altman assessments. The most appropriate g force threshold (smallest mean difference compared with video analyst coding) was lower for all forwards positions (2.5 g) than for all backs positions (3.5 g). The Bland-Altman 95% limits of agreement indicated that there may be a substantial over- or underestimation of collisions coded via GPS micro-technology when using expert video analyst coding as the reference comparator. The manipulation of the g force thresholds applied to data acquired by GPS micro-technology units based on incremental thresholds of 0.5 g does not provide a reliable tool for the accurate coding of collisions in rugby union. Future research should aim to investigate smaller g force threshold increments and determine the events that cause coding of false positives.

Making neurorehabilitation fun: Multiplayer training via damping forces balancing differences in skill levels.

PubMed

Baur, Kilian; Wolf, Peter; Riener, Robert; Duarte, Jaime E

2017-07-01

Multiplayer environments are thought to increase the training intensity in robot-aided rehabilitation therapy after stroke. We developed a haptic-based environment to investigate the dynamics of two-player training performing time-constrained reaching movements using the ARMin rehabilitation robot. We implemented a challenge level adaptation algorithm that controlled a virtual damping coefficient to reach a desired success rate. We tested the algorithm's effectiveness in regulating the success rate during game play in a simulation with computer-controlled players, in a feasibility study with six unimpaired players, and in a single session with one stroke patient. The algorithm demonstrated its capacity to adjust the damping coefficient to reach three levels of success rate (low [50%], moderate [70%], and high [90%]) during singleplayer and multiplayer training. For the patient - tested in single-player mode at the moderate success rate only - the algorithm showed also promising behavior. Results of the feasibility study showed that to increase the player's willingness to play at a more challenging task condition, the effect of the challenge level adaptation - regardless of being played in single player or multiplayer mode - might be more important than the provision of multiplayer setting alone. Furthermore, the multiplayer setting tends to be a motivating and encouraging therapy component. Based on these results we will optimize and expand the multiplayer training platform and further investigate multiplayer settings in stroke therapy.

Causes of anterior cruciate ligament injuries.

PubMed

Ristić, Vladimir; Ninković, Srdan; Harhaji, Vladimir; Milankov, Miroslav

2010-01-01

In order to prevent anterior cruciate ligament injuries it is necessary to define risk factors and to analyze the most frequent causes of injuries--that being the aim of this study. The study sample consisted of 451 surgically treated patients, including 400 sportsmen (65% of them being active and 35% recreational sportsmen), 29% female and 71% male; of whom 90% were younger than 35. Sports injuries, as the most frequent cause of anterior cruciate ligament injuries, were recorded in 88% of patients (non-contact ones in 78% and contact ones in 22%), injuries occurring in everyday activities in 11% and in traffic in 1%. Among sportsmen, reconstruction of the anterior cruciate ligament was most frequently performed in football players (48%), then in handball players (22%), basketball players (13%), volleyball players (8%), martial arts fighters (4%). However, the injury incidence was the highest among the active basketball players (1 injured among 91 active players). Type of footwear, warming up before the activity, genetic predisposition and everyday therapy did not have a significant influence on getting injured. Anterior cruciate ligament injuries happened three times more often during matches, in the middle and at the end of a match and training session (79%), at landing after the jump or when changing direction of movement (75%) without a contact with other competitors, on dry surfaces (79%), among not so well prepared sportsmen.

Chess players' eye movements reveal rapid recognition of complex visual patterns: Evidence from a chess-related visual search task.

PubMed

Sheridan, Heather; Reingold, Eyal M

2017-03-01

To explore the perceptual component of chess expertise, we monitored the eye movements of expert and novice chess players during a chess-related visual search task that tested anecdotal reports that a key differentiator of chess skill is the ability to visualize the complex moves of the knight piece. Specifically, chess players viewed an array of four minimized chessboards, and they rapidly searched for the target board that allowed a knight piece to reach a target square in three moves. On each trial, there was only one target board (i.e., the "Yes" board), and for the remaining "lure" boards, the knight's path was blocked on either the first move (the "Easy No" board) or the second move (i.e., "the Difficult No" board). As evidence that chess experts can rapidly differentiate complex chess-related visual patterns, the experts (but not the novices) showed longer first-fixation durations on the "Yes" board relative to the "Difficult No" board. Moreover, as hypothesized, the task strongly differentiated chess skill: Reaction times were more than four times faster for the experts relative to novices, and reaction times were correlated with within-group measures of expertise (i.e., official chess ratings, number of hours of practice). These results indicate that a key component of chess expertise is the ability to rapidly recognize complex visual patterns.

Defining the Process of a Cardiovascular Risk Assessment Program: Lessons Learnt From Cardiac Assessment of Elite Soccer Players in the United Kingdom.

PubMed

Speers, Christopher; Seth, Ajai Narain; Patel, Kiran Chhaganbhai; Rakhit, Dhrubo Jyoti; Gillett, Mark James

2017-12-14

Retrospectively analyze the cardiac assessment process for elite soccer players, and provide team physicians with a systematic guide to managing longitudinal cardiac risk. Descriptive Epidemiology Study. Cardiac assessments incorporating clinical examination, 12-lead ECG, echocardiography, and health questionnaire. Soccer players at 5 professional clubs in England, the United Kingdom. Data was retrospectively collected, inspected, and analyzed to determine their clinical management and subsequent follow-up. Over 2 years, 265 soccer players, aged 13 to 37 years with 66% of white European ethnicity, were included in the cohort. Eleven percent had "not-normal" assessments, of these assessments, 83% were considered gray screens, falling into three broad categories: structural cardiac features (including valvular abnormalities), functional cardiac features, and electrocardiogram changes. After cardiology consultation, all assessments were grouped into low, enhanced and high-risk categories for ongoing longitudinal risk management. Overall clear-cut pathology was identified in 2%. Cardiovascular assessment is a vital tool in identifying athletes at risk of sudden cardiac death to mitigate their risk through surveillance, intervention, or participation restriction. The decision whether a player is fit to play or not requires a robust risk assessment followed by input from a multidisciplinary team that includes both the team physician and cardiologist. This educational article proposes a clinical management pathway to aid clinicians with this process. Sudden cardiac death is the important medical cause of death during exercise. The team physician should assume responsibility for the management of the longitudinal risk of their players' cardiac assessments in conjunction with sports cardiologist.

Assessment of Cardiovascular Risk in Collegiate Football Players and Nonathletes

ERIC Educational Resources Information Center

Dobrosielski, Devon A.; Rosenbaum, Daryl; Wooster, Benjamin M.; Merrill, Michael; Swanson, John; Moore, J. Brian; Brubaker, Peter H.

2010-01-01

Collegiate American football players may be at risk for cardiovascular disease. Objective: To compare cardiovascular disease risk factors and cardiovascular structure and function parameters of football players, stratified by position, to a group of sedentary, nonathletes. Participants: Twenty-six collegiate football players and 13 nonathletes…

Comparison of posture among adolescent male volleyball players and non-athletes

PubMed Central

2014-01-01

Due to high training loads and frequently repeated unilateral exercises, several types of sports training can have an impact on the process of posture development in young athletes. The objective of the study was to assess and compare the postures of adolescent male volleyball players and their non-training peers. The study group comprised 104 volleyball players while the control group consisted of 114 non-training individuals aged 14-16 years. Body posture was assessed by the Moiré method. The volleyball players were significantly taller, and had greater body weight and fat-free mass. The analysis of posture relative to symmetry in the frontal and transverse planes did not show any significant differences between the volleyball players and non-athletes. Postural asymmetries were observed in both the volleyball players and the control participants. Lumbar lordosis was significantly less defined in the volleyball players compared to non-training individuals while no difference was observed in thoracic kyphosis. All athletes demonstrated a loss of lumbar lordosis and an increase in thoracic kyphosis. Significant differences in anteroposterior curvature of the spine between the volleyball players and the non-athletes might be associated with both training and body height. Considering the asymmetric spine overloads which frequently occur in sports training, meticulous posture assessment in young athletes seems well justified. PMID:25729154

How does knee pain affect trunk and knee motion during badminton forehand lunges?

PubMed

Huang, Ming-Tung; Lee, Hsing-Hsan; Lin, Cheng-Feng; Tsai, Yi-Ju; Liao, Jen-Chieh

2014-01-01

Badminton requires extensive lower extremity movement and a precise coordination of the upper extremity and trunk movements. Accordingly, this study investigated motions of the trunk and the knee, control of dynamic stability and muscle activation patterns of individuals with and without knee pain. Seventeen participants with chronic knee pain and 17 healthy participants participated in the study and performed forehand forward and backward diagonal lunges. This study showed that those with knee pain exhibited smaller knee motions in frontal and horizontal planes during forward lunge but greater knee motions in sagittal plane during backward lunge. By contrast, in both tasks, the injured group showed a smaller value on the activation level of the paraspinal muscles in pre-impact phase, hip-shoulder separation angle, trunk forward inclination range and peak centre of mass (COM) velocity. Badminton players with knee pain adopt a more conservative movement pattern of the knee to minimise recurrence of knee pain. The healthy group exhibit better weight-shifting ability due to a greater control of the trunk and knee muscles. Training programmes for badminton players with knee pain should be designed to improve both the neuromuscular control and muscle strength of the core muscles and the knee extensor with focus on the backward lunge motion.

Do force-time and power-time measures in a loaded jump squat differentiate between speed performance and playing level in elite and elite junior rugby union players?

PubMed

Hansen, Keir T; Cronin, John B; Pickering, Stuart L; Douglas, Lee

2011-09-01

The purpose of this study was to investigate the discriminative ability of rebound jump squat force-time and power-time measures in differentiating speed performance and competition level in elite and elite junior rugby union players. Forty professional rugby union players performed 3 rebound jump squats with an external load of 40 kg from which a number of force-time and power-time variables were acquired and analyzed. Additionally, players performed 3 sprints over 30 m with timing gates at 5, 10, and 30 m. Significant differences (p < 0.05) between the fastest 20 and slowest 20 athletes, and elite (n = 25) and elite junior (n = 15) players in speed and force-time and power-time variables were determined using independent sample t-tests. The fastest and slowest sprinters over 10 m differed in peak power (PP) expressed relative to body weight. Over 30 m, there were significant differences in peak velocity and relative PP and rate of power development. There was no significant difference in speed over any distance between elite and elite junior rugby union players; however, a number of force and power variables including peak force, PP, force at 100 milliseconds from minimum force, and force and impulse 200 milliseconds from minimum force were significantly (p < 0.05) different between playing levels. Although only power values expressed relative to body weight were able to differentiate speed performance, both absolute and relative force and power values differentiated playing levels in professional rugby union players. For speed development in rugby union players, training strategies should aim to optimize the athlete's power to weight ratio, and lower body resistance training should focus on movement velocity. For player development to transition elite junior players to elite status, adding lean mass is likely to be most beneficial.

A survey of “mental hardiness” and “mental toughness” in professional male football players

PubMed Central

2014-01-01

Background It is not uncommon for chiropractors to be associated with sports teams for injury prevention, treatment, or performance enhancement. There is increasing acceptance of the importance of sports psychology in the overall management of athletes. Recent findings indicate mental hardiness can be determined reliably using specific self-assessment questionnaires. This study set out to investigate the hardiness scores of professional footballers and examine the correlation between two questionnaires. It also included a mental hardiness rating of players by two coaches, and examined differences in hardiness and mental toughness between national and international players. Methods Two self-assessment questionnaires (modified Sports Mental Toughness Questionnaire [SMTQ-M] and Psychological Performance Inventory [PPI-A]) were completed by 20 male professional footballers. Two coaches, independently rated each player. A percentage score from each questionnaire was awarded each player and an average score was calculated ({SMTQ-M % + PPI-A %} ÷ 2). The PPI-A and SMTQ-M scores obtained for each player were analysed for correlation with Pearson’s correlation coefficient. Cohen’s kappa inter-reliability coefficient was used to determine agreement between coaches, and between the players’ hardiness scores and coaches’ ratings. The independent t-test was used to examine differences between national and international players. Results The players’ scores obtained from PPI-A and SMTQ-M correlated well (r = 0.709, p < 0.001). The coaches ratings showed significant, weak to moderate agreement (Cohen's kappa = 0.33). No significant agreement was found between player self-assessments and coaches’ ratings. The average ({SMTQ-M % + PPI-A %} ÷ 2) mean score was 77% (SD = 7.98) with international players scoring 7.4% (p = 0.04) higher than non-international players. Conclusions The questionnaires (SMTQ-M and PPI-A) correlated well in their outcome scores. These findings suggest that coaches moderately agree when assessing the level of mental hardiness of football players. There was no agreement between player self-assessment and ratings by coaches. Footballers who play or had played for national teams achieved slightly higher mental hardiness scores. Either questionnaire can offer the clinician a cost-effective, valuable measure of an individual’s psychological attributes, which could be relevant within the wider context of bio-psycho-social model of care. PMID:24735867

Neuromechanical evidence of improved neuromuscular control around knee joint in volleyball players.

PubMed

Masci, Ilaria; Vannozzi, Giuseppe; Gizzi, Leonardo; Bellotti, Pasquale; Felici, Francesco

2010-02-01

The aim of the present work was to verify that skilled volleyball players present specific adaptations in both neuromuscular control and movement biomechanics, showing an improved neuromuscular control around the knee joint than in non-jumper athletes. Seven male volleyball players and seven male non-jumper athletes were recruited for this study. The following tests were performed in a random order: single countermovement jump (CMJ), single squat jump. At the end of the series, subjects performed a repetitive CMJ test. Electromyographic signals were recorded from vastus lateralis and biceps femoris muscles on both sides. Ground reaction forces and moments were measured with a force plate. Volleyball athletes performed better in all tests and were more resistant to fatigue than non-jumper athletes. Furthermore, volleyball athletes showed a reduced co-activation of knee flexor/extensor muscles. The present results seem to stand for a neural adaptation of the motor control scheme to training.

The volleyball athlete's shoulder: biomechanical adaptations and injury associations.

PubMed

Challoumas, Dimitrios; Stavrou, Antonio; Dimitrakakis, Georgios

2017-06-01

In volleyball, the dominant shoulder of the athlete undergoes biomechanical and morphological adaptations; however, definitive conclusions about their exact nature, aetiology, purpose and associations with shoulder injury have not been reached. We present a systematic review of the existing literature describing biomechanical adaptations in the dominant shoulders of volleyball players and factors that may predispose to shoulder pain/injury. A thorough literature search via Medline, EMBASE and SCOPUS was conducted for original studies of volleyball players and 15 eligible articles were identified. Assessment of study quality was performed using the STROBE statement. The reviewed literature supports the existence of a glenohumeral internal rotation deficit (GIRD) and a possible (and less pronounced) external rotation gain in the dominant vs. the non-dominant shoulder of volleyball athletes. Unlike other overhead sports, the GIRD in volleyball athletes appears to be anatomical as a response to the repetitive overhead movements and not to be associated with shoulder pain/injury. Additionally, the dominant shoulder exhibits muscular imbalance, which appears to be a significant risk factor for shoulder pain. Strengthening of the external rotators should be used alongside shoulder stretching and joint mobilisations, core strengthening and optimisation of spike technique as part of injury management and prevention programmes.

Motor Function in Former Professional Football Players with History of Multiple Concussions.

PubMed

Tarazi, Apameh; Tator, Charles H; Wennberg, Richard; Ebraheem, Ahmed; Green, Robin E A; Collela, Brenda; Saverino, Christina; Khodadadi, Mozghan; Misquitta, Karen; Tartaglia, Maria Carmela

2018-04-15

The objective of this study was to assess the incidence of motor impairment in former professional Canadian Football League (ex-CFL) players with multiple concussions. We investigated motor symptoms and signs in 45 ex-CFL players with multiple concussions and 25 age- and education-matched healthy controls with no history of concussion. Neurological assessment included items from the SCAT3 (Sport Concussion Assessment Tool 3) and the Unified Parkinson's Disease Rating Scale part III (UPDRS-Part III). A performance-based measurement of manual motor function was undertaken using the Grooved Pegboard test. Cognition was measured with patient-reported outcomes for memory, executive and behavioral symptoms as well as performance-based measures of memory and executive function. Symptoms of anxiety and depression were measured using the Personality Assessment Inventory. There was no significant difference between the ex-CFL players and controls on the UPDRS-Part III scores, and neither group reported clinically significant motor complaints. Ex-CFL players did not perform differently from control subjects on the Grooved Pegboard test. In contrast, with regard to cognitive and mood testing, players were more symptomatic: The ex-CFL players reported significantly more memory (77.8% vs. 16%, respectively, p < 0.001), executive (53.3% vs. 8%, respectively, p < 0.001), and behavioral symptoms (66.7% vs. 20%, respectively, p < 0.001). No significant differences were found when comparing ex-CFL players and controls in performance on memory and executive tests. In summary, in a group of retired CFL players who self-reported declines in memory, executive and behavioral symptoms, no motor symptoms were reported and no motor signs were detected.

A dynamical system perspective to understanding badminton singles game play.

PubMed

Chow, Jia Yi; Seifert, Ludovic; Hérault, Romain; Chia, Shannon Jing Yi; Lee, Miriam Chang Yi

2014-02-01

By altering the task constraints of cooperative and competitive game contexts in badminton, insights can be obtained from a dynamical systems perspective to investigate the underlying processes that results in either a gradual shift or transition of playing patterns. Positional data of three pairs of skilled female badminton players (average age 20.5±1.38years) were captured and analyzed. Local correlation coefficient, which provides information on the relationship of players' displacement data, between each pair of players was computed for angle and distance from base position. Speed scalar product was in turn established from speed vectors of the players. The results revealed two patterns of playing behaviors (i.e., in-phase and anti-phase patterns) for movement displacement. Anti-phase relation was the dominant coupling pattern for speed scalar relationships among the pairs of players. Speed scalar product, as a collective variable, was different between cooperative and competitive plays with a greater variability in amplitude seen in competitive plays leading to a winning point. The findings from this study provide evidence for increasing stroke variability to perturb existing stable patterns of play and highlights the potential for speed scalar product to be a collective variable to distinguish different patterns of play (e.g., cooperative and competitive). Copyright © 2013 Elsevier B.V. All rights reserved.

Jump Landing Characteristics Predict Lower Extremity Injuries in Indoor Team Sports.

PubMed

van der Does, H T D; Brink, M S; Benjaminse, A; Visscher, C; Lemmink, K A P M

2016-03-01

The aim of this study is to investigate the predictive value of landing stability and technique to gain insight into risk factors for ankle and knee injuries in indoor team sport players. Seventy-five male and female basketball, volleyball or korfball players were screened by measuring landing stability after a single-leg jump landing and landing technique during a repeated counter movement jump by detailed 3-dimensional kinematics and kinetics. During the season 11 acute ankle injuries were reported along with 6 acute and 7 overuse knee injuries by the teams' physical therapist. Logistic regression analysis showed less landing stability in the forward and diagonal jump direction (OR 1.01-1.10, p≤0.05) in players who sustained an acute ankle injury. Furthermore landing technique with a greater ankle dorsiflexion moment increased the risk for acute ankle injury (OR 2.16, p≤0.05). A smaller knee flexion moment and greater vertical ground reaction force increased the risk of an overuse knee injury (OR 0.29 and 1.13 respectively, p≤0.05). Less one-legged landing stability and suboptimal landing technique were shown in players sustaining an acute ankle and overuse knee injury compared to healthy players. Determining both landing stability and technique may further guide injury prevention programs. © Georg Thieme Verlag KG Stuttgart · New York.

Exploring Team Passing Networks and Player Movement Dynamics in Youth Association Football

PubMed Central

Coutinho, Diogo; Santos, Sara; Lago-Penas, Carlos; Jiménez, Sergio; Sampaio, Jaime

2017-01-01

Understanding how youth football players base their game interactions may constitute a solid criterion for fine-tuning the training process and, ultimately, to achieve better individual and team performances during competition. The present study aims to explore how passing networks and positioning variables can be linked to the match outcome in youth elite association football. The participants included 44 male elite players from under-15 and under-17 age groups. A passing network approach within positioning-derived variables was computed to identify the contributions of individual players for the overall team behaviour outcome during a simulated match. Results suggested that lower team passing dependency for a given player (expressed by lower betweenness network centrality scores) and high intra-team well-connected passing relations (expressed by higher closeness network centrality scores) were related to better outcomes. The correlation between the dyads’ positioning regularity and the passing density showed a most likely higher correlation in under-15 (moderate effect), indicating a possible more dependence of the ball position rather than in the under-17 teams (small/unclear effects). Overall, this study emphasizes the potential of coupling notational analyses with spatial-temporal relations to produce a more functional and holistic understanding of teams’ sports performance. Also, the social network analysis allowed to reveal novel key determinants of collective performance. PMID:28141823

Specific physiological and biomechanical performance in elite, sub-elite and in non-elite male team handball players.

PubMed

Wagner, Herbert; Fuchs, Philip X; von Duvillard, Serge P

2018-01-01

Team handball is a dynamic sport game that is played professionally in numerous countries. However, knowledge about training and competition is based mostly on practical experience due to limited scientific studies. Consequently, the aims of our study were to compare specific physiological and biomechanical performance in elite, sub-elite and in non-elite male team handball players. Thirty-six elite, sub-elite and non-elite male team handball players performed a game based performance test, upper-body and lower-body strength tests, 30-m sprint test, counter movement jump test and an incremental treadmill running test. Significant differences (P<0.05) were found for the peak oxygen uptake, heart rate, offense and defense time, jump height and ball velocity during the jump throw in the game based performance test, maximal oxygen uptake in the incremental treadmill running test as well as in maximal leg strength and leg explosive strength in the isometric strength test. Elite male players have an enhanced specific agility, a better throwing performance, a higher team handball specific oxygen uptake and higher leg strength compared to sub-elite and non-elite players. Based on these results we recommend that training in team handball should focus on game based training methods to improve performance in specific agility, endurance and technique.

Coordination and variability in the elite female tennis serve.

PubMed

Whiteside, David; Elliott, Bruce Clifford; Lay, Brendan; Reid, Machar

2015-01-01

Enhancing the understanding of coordination and variability in the tennis serve may be of interest to coaches as they work with players to improve performance. The current study examined coordinated joint rotations and variability in the lower limbs, trunk, serving arm and ball location in the elite female tennis serve. Pre-pubescent, pubescent and adult players performed maximal effort flat serves while a 22-camera 500 Hz motion analysis system captured three-dimensional body kinematics. Coordinated joint rotations in the lower limbs and trunk appeared most consistent at the time players left the ground, suggesting that they coordinate the proximal elements of the kinematic chain to ensure that they leave the ground at a consistent time, in a consistent posture. Variability in the two degrees of freedom at the elbow became significantly greater closer to impact in adults, possibly illustrating the mechanical adjustments (compensation) these players employed to manage the changing impact location from serve to serve. Despite the variable ball toss, the temporal composition of the serve was highly consistent and supports previous assertions that players use the location of the ball to regulate their movement. Future work should consider these associations in other populations, while coaches may use the current findings to improve female serve performance.

Performance enhancement among adolescent players after 10 weeks of pitching training with appropriate baseball weights.

PubMed

Yang, Wen-Wen; Liu, Ya-Chen; Lu, Lee-Chang; Chang, Hsiao-Yun; Chou, Paul Pei-Hsi; Liu, Chiang

2013-12-01

Compared with regulation-weight baseballs, lightweight baseballs generate lower torque on the shoulder and elbow joints without altering the pitching movement and timing. This study investigates the throwing accuracy, throwing velocity, arm swing velocity, and maximum shoulder external rotation (MSER) of adolescent players after 10 weeks of pitching training with appropriate lightweight baseballs. We assigned 24 adolescent players to a lightweight baseball group (group L) and a regulation-weight baseball group (group R) based on their pretraining throwing velocity. Both groups received pitching training 3 times per week for 10 weeks with 4.4- and 5-oz baseballs. The players' throwing accuracy, throwing velocity, arm swing velocity, and MSER were measured from 10 maximum efforts throws using a regulation-weight baseball before and after undergoing the pitching training. The results showed that the players in group L significantly increased their throwing velocity and arm swing velocity (p < 0.05) after 10 weeks of pitching training with the 4.4-oz baseball, whereas group R did not (p > 0.05). Furthermore, the percentage change in the throwing velocity and arm swing velocity of group L was significantly superior to that of group R (p < 0.05). Thus, we concluded that the 10 weeks of pitching training with an appropriate lightweight baseball substantially enhanced the arm swing velocity and throwing velocity of the adolescent baseball players. These findings suggest that using a lightweight baseball, which can reduce the risk of injury without altering pitching patterns, has positive training effects on players in the rapid physical growth and technique development stage.

Spatial distribution of surface EMG on trapezius and lumbar muscles of violin and cello players in single note playing.

PubMed

Afsharipour, Babak; Petracca, Francesco; Gasparini, Mauro; Merletti, Roberto

2016-12-01

Musicians activate their muscles in different patterns, depending on their posture, the instrument being played, and their experience level. Bipolar surface electrodes have been used in the past to monitor such activity, but this method is highly sensitive to the location of the electrode pair. In this work, the spatial distribution of surface EMG (sEMG) of the right trapezius and right and left erector spinae muscles were studied in 16 violin players and 11 cello players. Musicians played their instrument one string at a time in sitting position with/without backrest support. A 64 sEMG electrode (16×4) grid, 10mm inter-electrode distance (IED), was placed over the middle and lower trapezius (MT and LT) of the bowing arm. Two 16×2 electrode grids (IED=10mm) were placed on the left and right erector spinae muscles. Subjects played each of the four strings of the instrument either in large (1bow/s) or detaché tip/tail (8bows/s) bowing in two sessions (two days). In each of two days, measurements were repeated after half an hour of exercise to see the effect of exercise on the muscle activity and signal stability. A "muscle activity index" (MAI) was defined as the spatial average of the segmented active region of the RMS map. Spatial maps were automatically segmented using the watershed algorithm and thresholding. Results showed that, for violin players, sliding the bow upward from the tip toward the tail results in a higher MAI for the trapezius muscle than a downward bow. On the contrary, in cello players, higher MAI is produced in the tail to tip movement. For both instruments, an increasing MAI in the trapezius was observed as the string position became increasingly lateral, from string 1 (most medial) toward string 4 (most lateral). Half an hour of performance did not cause significant differences between the signal quality and the MAI values measured before and after the exercise. The MAI of the left and right erector spinae was smaller in the case of backrest support, especially for violin players. Back muscles of violin and cello players were activated asymmetrically, specifically in fast movements (detaché tip/tail). These findings demonstrate the sensitivity and stability of the technique and justify more extensive investigation following this proof of concept. Copyright © 2016 Elsevier Ltd. All rights reserved.

Executive Functions Predict the Success of Top-Soccer Players

PubMed Central

Vestberg, Torbjörn; Gustafson, Roland; Maurex, Liselotte; Ingvar, Martin; Petrovic, Predrag

2012-01-01

While the importance of physical abilities and motor coordination is non-contested in sport, more focus has recently been turned toward cognitive processes important for different sports. However, this line of studies has often investigated sport-specific cognitive traits, while few studies have focused on general cognitive traits. We explored if measures of general executive functions can predict the success of a soccer player. The present study used standardized neuropsychological assessment tools assessing players' general executive functions including on-line multi-processing such as creativity, response inhibition, and cognitive flexibility. In a first cross-sectional part of the study we compared the results between High Division players (HD), Lower Division players (LD) and a standardized norm group. The result shows that both HD and LD players had significantly better measures of executive functions in comparison to the norm group for both men and women. Moreover, the HD players outperformed the LD players in these tests. In the second prospective part of the study, a partial correlation test showed a significant correlation between the result from the executive test and the numbers of goals and assists the players had scored two seasons later. The results from this study strongly suggest that results in cognitive function tests predict the success of ball sport players. PMID:22496850

Dynamics of tactical behaviour in association football when manipulating players' space of interaction

PubMed Central

Torrents, Carlota; Gonçalves, Bruno; Torres-Ronda, Lorena; Sampaio, Jaime; Hristovski, Robert

2017-01-01

The analysis of positional data in association football allows the spatial distribution of players during matches to be described in order to improve the understanding of tactical-related constraints on the behavioural dynamics of players. The aim of this study was to identify how players’ spatial restrictions affected the exploratory tactical behaviour and constrained the perceptual-motor workspace of players in possession of the ball, as well as inter-player passing interactions. Nineteen professional outfield male players were divided into two teams of 10 and 9 players, respectively. The game was played under three spatial constraints: a) players were not allowed to move out of their allocated zones, except for the player in possession of the ball; b) players were allowed to move to an adjacent zone, and; c) non-specific spatial constraints. Positional data was captured using a 5 Hz interpolated GPS tracking system and used to define the configuration states of players for each second in time. The configuration state comprised 37 categories derived from tactical actions, distance from the nearest opponent, distance from the target and movement speed. Notational analysis of players in possession of the ball allowed the mean time of ball possession and the probabilities of passing the ball between players to be calculated. The results revealed that the players’ long-term exploratory behaviour decreased and their short-term exploration increased when restricting their space of interaction. Relaxing players’ positional constraints seemed to increase the speed of ball flow dynamics. Allowing players to move to an adjacent sub-area increased the probabilities of interaction with the full-back during play build-up. The instability of the coordinative state defined by being free from opponents when players had the ball possession was an invariant feature under all three task constraints. By allowing players to move to adjacent sub-areas, the coordinative state became highly unstable when the distance from the target decreased. Ball location relative to the scoring zone and interpersonal distance constitute key environmental information that constrains the players’ coordinative behaviour. Based on our results, dynamic overlap is presented as a good option to capture tactical performance. Moreover, the selected collective (i.e. relational) variables would allow coaches to identify the effects of training drills on teams and players’ behaviour. More research is needed considering these type variables to understand how the manipulation of constraints induce a more stable or flexible dynamical structure of tactical behaviour. PMID:28708868

Technical player profiles related to the physical fitness of young female volleyball players predict team performance.

PubMed

Dávila-Romero, C; Hernández-Mocholí, M A; García-Hermoso, A

2015-03-01

This study is divided into three sequential stages: identification of fitness and game performance profiles (individual player performance), an assessment of the relationship between these profiles, and an assessment of the relationship between individual player profiles and team performance during play (in championship performance). The overall study sample comprised 525 (19 teams) female volleyball players aged 12-16 years and a subsample (N.=43) used to examine study aims one and two was selected from overall sample. Anthropometric, fitness and individual player performance (actual game) data were collected in the subsample. These data were analyzed through clustering methods, ANOVA and independence chi-square test. Then, we investigated whether the proportion of players with the highest individual player performance profile might predict a team's results in the championship. Cluster analysis identified three volleyball fitness profiles (high, medium, and low) and two individual player performance profiles (high and low). The results showed a relationship between both types of profile (fitness and individual player performance). Then, linear regression revealed a moderate relationship between the number of players with a high volleyball fitness profile and a team's results in the championship (R2=0.23). The current study findings may enable coaches and trainers to manage training programs more efficiently in order to obtain tailor-made training, identify volleyball-specific physical fitness training requirements and reach better results during competitions.

Synchrony in Joint Action Is Directed by Each Participant’s Motor Control System

PubMed Central

Noy, Lior; Weiser, Netta; Friedman, Jason

2017-01-01

In this work, we ask how the probability of achieving synchrony in joint action is affected by the choice of motion parameters of each individual. We use the mirror game paradigm to study how changes in leader’s motion parameters, specifically frequency and peak velocity, affect the probability of entering the state of co-confidence (CC) motion: a dyadic state of synchronized, smooth and co-predictive motions. In order to systematically study this question, we used a one-person version of the mirror game, where the participant mirrored piece-wise rhythmic movements produced by a computer on a graphics tablet. We systematically varied the frequency and peak velocity of the movements to determine how these parameters affect the likelihood of synchronized joint action. To assess synchrony in the mirror game we used the previously developed marker of co-confident (CC) motions: smooth, jitter-less and synchronized motions indicative of co-predicative control. We found that when mirroring movements with low frequencies (i.e., long duration movements), the participants never showed CC, and as the frequency of the stimuli increased, the probability of observing CC also increased. This finding is discussed in the framework of motor control studies showing an upper limit on the duration of smooth motion. We confirmed the relationship between motion parameters and the probability to perform CC with three sets of data of open-ended two-player mirror games. These findings demonstrate that when performing movements together, there are optimal movement frequencies to use in order to maximize the possibility of entering a state of synchronized joint action. It also shows that the ability to perform synchronized joint action is constrained by the properties of our motor control systems. PMID:28443047

Physiological Profile and Activity Pattern of Minor Gaelic Football Players.

PubMed

Cullen, Bryan D; Roantree, Mark T; McCarren, Andrew L; Kelly, David T; OʼConnor, Paul L; Hughes, Sarah M; Daly, Pat G; Moyna, Niall M

2017-07-01

Cullen, BD, Roantree, M, McCarren, A, Kelly, DT, O'Connor, PL, Hughes, SM, Daly, PG, and Moyna1, NM. Physiological profile and activity pattern of minor Gaelic football players. J Strength Cond Res 31(7): 1811-1820, 2017-The purpose of this study was to evaluate the physiological profile and activity pattern in club- and county-level under-18 (U-18) Gaelic football players relative to playing position. Participants (n = 85) were analyzed during 17 official 15-a-side matches using global positioning system technology (SPI Pro X II; GPSports Systems, Canberra, Australia) and heart rate (HR) telemetry. During the second part of this study, 63 participants underwent an incremental treadmill test to assess their maximal oxygen uptake (V[Combining Dot Above]o2max) and peak HR (HRmax). Players covered a mean distance of 5,774 ± 737 m during a full 60-minute match. The mean %HRmax and %V[Combining Dot Above]O2max observed during the match play were 81.6 ± 4.3% and 70.1 ± 7.75%, respectively. The playing level had no effect on the distance covered, player movement patterns, or %HRmax observed during match play. Midfield players covered significantly greater distance than defenders (p = 0.033). Playing position had no effect on %HRmax or the frequency of sprinting or high-intensity running during match play. The frequency of jogging, cruise running, striding (p = 0.000), and walking (p = 0.003) was greater in the midfield position than in the forward position. Time had a significant effect (F(1,39) = 33.512, p-value = 0.000, and (Equation is included in full-text article.)= 0.462) on distance covered and %HRmax, both of which showed a reduction between playing periods. Gaelic football is predominantly characterized by low-to-moderate intensity activity interspersed with periods of high-intensity running. The information provided may be used as a framework for coaches in the design and prescription of training strategies. Positional specific training may be warranted given the comparatively greater demands observed in the midfield playing position. Replicating the demands of match play in training may reduce the decline in distance covered and %HRmax observed during the second half of match play.

The physical demands of elite English rugby union.

PubMed

Roberts, Simon P; Trewartha, Grant; Higgitt, Rob J; El-Abd, Joe; Stokes, Keith A

2008-06-01

The aim of this study was to assess the physical demands of elite English rugby union match-play. Player movements were captured by five distributed video cameras and then reconstructed on a two-dimensional plane representing the pitch. Movements based on speeds were categorized as standing, walking, jogging, and medium-intensity running (low-intensity activity), and high-intensity running, sprinting, and static exertion (scrummaging, rucking, mauling, and tackling) (high-intensity activity). Position groups were defined as forwards (tight and loose) and backs (inside and outside). Backs travelled more total distance than forwards (6127 m, s=724 vs. 5581 m, s=692; P<0.05) and greater distances in walking (2351 m, s=287 vs. 1928 m, s=2342; P<0.001) and high-intensity running (448 m, s=149 vs. 298 m, s=107; P<0.05). Forwards performed more high-intensity activity than backs (9:09 min:s, s=1:39 vs. 3:04 min:s, s=1:01; P<0.001), which was attributable to more time spent in static exertion (7:56 min:s, s=1:56 vs. 1:18 min:s, s=0:30; P<0.001), although backs spent more time in high-intensity running (0:52 min:s, s=0:19 vs. 1:19 min:s, s=0:26; P=0.004). Players travelled a greater distance in the first 10 min compared with 50-60 and 70-80 min, but there was no difference in the amount of high-intensity activity performed during consecutive 10-min periods during match-play. These results show the differing physical demands between forwards and backs with no evident deterioration in high-intensity activity performed during match-play.

Effects of a 6-week junior tennis conditioning program on service velocity.

PubMed

Fernandez-Fernandez, Jaime; Ellenbecker, Todd; Sanz-Rivas, David; Ulbricht, Alexander; Ferrautia, Alexander

2013-01-01

This study examined the effects of a 6-week strength-training program on serve velocity in youth tennis players. Thirty competitive healthy and nationally ranked male junior tennis players (13 years of age) were randomly and equally divided into control and training groups. The training group performed 3 sessions (60-70 min) weekly for 6 weeks, comprising core strength, elastic resistance and medicine ball exercises. Both groups (control and training) also performed a supervised stretching routine at the end of each training session, during the 6 week intervention. Service velocity, service accuracy and shoulder internal/external rotation were assessed initially and at the end of the 6-week conditioning program for both, control and training groups. There was a significant improvement in the serve velocity for the training group (p = 0. 0001) after the intervention, whereas in the control group there were no differences between pre and post-tests (p = 0.29). Serve accuracy was not affected in the training group (p = 0.10), nor in the control group (p = 0.15). Shoulder internal/external rotation ROM significantly improved in both groups, training (p = 0.001) and control (p = 0.0001). The present results showed that a short- term training program for young tennis players, using minimum equipment and effort, can result in improved tennis performance (i.e., serve velocity) and a reduction in the risk of a possible overuse injury, reflected by an improvement in shoulder external/internal range of motion. Key PointsA short-term training program for young tennis players, using minimum equipment and effort, can result in improved tennis performance and a reduction in the risk of a possible overuse injury, reflected by an improvement in shoulder external/internal range of motionA combination of core stabilization, elastic resistance exercises, and upper body plyometric exercises (i.e., medicine ball throws), focussing on the primary muscle groups and stabilizers involved in tennis specific movement patterns, could be appropriate for development tennis playersStretching exercises are recommended in the cool-down phase following matches or training sessions.

Effects of A 6-Week Junior Tennis Conditioning Program on Service Velocity

PubMed Central

Fernandez-Fernandez, Jaime; Ellenbecker, Todd; Sanz-Rivas, david; Ulbricht, Alexander; Ferrautia, lexander

2013-01-01

This study examined the effects of a 6-week strength-training program on serve velocity in youth tennis players. Thirty competitive healthy and nationally ranked male junior tennis players (13 years of age) were randomly and equally divided into control and training groups. The training group performed 3 sessions (60-70 min) weekly for 6 weeks, comprising core strength, elastic resistance and medicine ball exercises. Both groups (control and training) also performed a supervised stretching routine at the end of each training session, during the 6 week intervention. Service velocity, service accuracy and shoulder internal/external rotation were assessed initially and at the end of the 6-week conditioning program for both, control and training groups. There was a significant improvement in the serve velocity for the training group (p = 0. 0001) after the intervention, whereas in the control group there were no differences between pre and post-tests (p = 0.29). Serve accuracy was not affected in the training group (p = 0.10), nor in the control group (p = 0.15). Shoulder internal/external rotation ROM significantly improved in both groups, training (p = 0.001) and control (p = 0.0001). The present results showed that a short- term training program for young tennis players, using minimum equipment and effort, can result in improved tennis performance (i.e., serve velocity) and a reduction in the risk of a possible overuse injury, reflected by an improvement in shoulder external/internal range of motion. Key Points A short-term training program for young tennis players, using minimum equipment and effort, can result in improved tennis performance and a reduction in the risk of a possible overuse injury, reflected by an improvement in shoulder external/internal range of motion A combination of core stabilization, elastic resistance exercises, and upper body plyometric exercises (i.e., medicine ball throws), focussing on the primary muscle groups and stabilizers involved in tennis specific movement patterns, could be appropriate for development tennis players Stretching exercises are recommended in the cool-down phase following matches or training sessions. PMID:24149801

Comparison of anthropometry, upper-body strength, and lower-body power characteristics in different levels of Australian football players.

PubMed

Bilsborough, Johann C; Greenway, Kate G; Opar, David A; Livingstone, Steuart G; Cordy, Justin T; Bird, Stephen R; Coutts, Aaron J

2015-03-01

The aim of this study was to compare the anthropometry, upper-body strength, and lower-body power characteristics in elite junior, sub-elite senior, and elite senior Australian Football (AF) players. Nineteen experienced elite senior (≥4 years Australian Football League [AFL] experience), 27 inexperienced elite senior (<4 years AFL experience), 22 sub-elite senior, and 21 elite junior AF players were assessed for anthropometric profile (fat-free soft tissue mass [FFSTM], fat mass, and bone mineral content) with dual-energy x-ray absorptiometry, upper-body strength (bench press and bench pull), and lower-body power (countermovement jump [CMJ] and squat jump with 20 kg). A 1-way analysis of variance assessed differences between the playing levels in these measures, whereas relationships between anthropometry and performance were assessed with Pearson's correlation. The elite senior and sub-elite senior players were older and heavier than the elite junior players (p ≤ 0.05). Both elite playing groups had greater total FFSTM than both the sub-elite and junior elite players; however, there were only appendicular FFSTM differences between the junior elite and elite senior players (p < 0.001). The elite senior playing groups were stronger and had greater CMJ performance than the lower level players. Both whole-body and regional FFSTM were correlated with bench press (r = 0.43-0.64), bench pull (r = 0.58-0.73), and jump squat performance measures (r = 0.33-0.55). Australian Football players' FFSTM are different between playing levels, which are likely because of training and partly explain the observed differences in performance between playing levels highlighting the importance of optimizing FFSTM in young players.

Prevalence of posterior elbow problems in Japanese high school baseball players.

PubMed

Kida, Yoshikazu; Morihara, Toru; Furukawa, Ryuhei; Sukenari, Tsuyoshi; Kotoura, Yoshihiro; Yoshioka, Naoki; Hojo, Tatsuya; Oda, Ryo; Arai, Yuji; Sawada, Koshiro; Fujiwara, Hiroyoshi; Kubo, Toshikazu

2016-09-01

Various posterior elbow problems cause posterior elbow pain among baseball players. We aimed to determine the prevalence and diagnoses associated with posterior elbow problems and post-treatment recovery time for returning to sports in Japanese high school baseball players when treated in the off-season. A total of 576 Japanese high school baseball players who participated in baseball skill training camp during the off-season were enrolled in the study. The elbow of each player's throwing arm was assessed by use of a questionnaire and physical examination. Players with abnormal results were advised to visit the hospital. Players who visited the hospital were initially treated conservatively and underwent surgery if necessary. Retrospectively, players with positive physical examination results associated with posterior elbow pain, defined as olecranon tenderness and/or a positive elbow extension impingement test, were selected. Information about their position, elbow pain, physical examination results, diagnosis, treatment, and recovery time before returning to playing sports was assessed. Olecranon tenderness and/or positive elbow extension impingement test results were found in 76 players (13.2%). Of these, 33 agreed to visit the hospital for further diagnostic imaging and 25 players (75.8%) were diagnosed with posteromedial elbow impingement. By the next spring, 87.9% of players returned to sport, and 100% of players returned to sport before the next summer. The average recovery period was 77 ± 47 days. Physical examinations related to posterior elbow injuries were positive in 13.2% of high school baseball players. The most common diagnosis for posterior elbow pain was posteromedial elbow impingement. All players returned to competitive sports activity levels within 77 ± 47 days. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Relationship Between Motor Variability, Accuracy, and Ball Speed in the Tennis Serve

PubMed Central

Antúnez, Ruperto Menayo; Hernández, Francisco Javier Moreno; García, Juan Pedro Fuentes; Vaíllo, Raúl Reina; Arroyo, Jesús Sebastián Damas

2012-01-01

The main objective of this study was to analyze the motor variability in the performance of the tennis serve and its relationship to performance outcome. Seventeen male tennis players took part in the research, and they performed 20 serves. Linear and non-linear variability during the hand movement was measured by 3D Motion Tracking. Ball speed was recorded with a sports radar gun and the ball bounces were video recorded to calculate accuracy. The results showed a relationship between the amount of variability and its non-linear structure found in performance of movement and the outcome of the serve. The study also found that movement predictability correlates with performance. An increase in the amount of movement variability could affect the tennis serve performance in a negative way by reducing speed and accuracy of the ball. PMID:23486998

Three-dimensional kinematics of the lower limbs during forward ice hockey skating.

PubMed

Upjohn, Tegan; Turcotte, René; Pearsall, David J; Loh, Jonathan

2008-05-01

The objectives of the study were to describe lower limb kinematics in three dimensions during the forward skating stride in hockey players and to contrast skating techniques between low- and high-calibre skaters. Participant motions were recorded with four synchronized digital video cameras while wearing reflective marker triads on the thighs, shanks, and skates. Participants skated on a specialized treadmill with a polyethylene slat bed at a self-selected speed for 1 min. Each participant completed three 1-min skating trials separated by 5 min of rest. Joint and limb segment angles were calculated within the local (anatomical) and global reference planes. Similar gross movement patterns and stride rates were observed; however, high-calibre participants showed a greater range and rate of joint motion in both the sagittal and frontal planes, contributing to greater stride length for high-calibre players. Furthermore, consequent postural differences led to greater lateral excursion during the power stroke in high-calibre skaters. In conclusion, specific kinematic differences in both joint and limb segment angle movement patterns were observed between low- and high-calibre skaters.

Effect of core stability training on throwing velocity in female handball players.

PubMed

Saeterbakken, Atle H; van den Tillaar, Roland; Seiler, Stephen

2011-03-01

The purpose was to study the effect of a sling exercise training (SET)-based core stability program on maximal throwing velocity among female handball players. Twenty-four female high-school handball players (16.6 ± 0.3 years, 63 ± 6 kg, and 169 ± 7 cm) participated and were initially divided into a SET training group (n = 14) and a control group (CON, n = 10). Both groups performed their regular handball training for 6 weeks. In addition, twice a week, the SET group performed a progressive core stability-training program consisting of 6 unstable closed kinetic chain exercises. Maximal throwing velocity was measured before and after the training period using photocells. Maximal throwing velocity significantly increased 4.9% from 17.9 ± 0.5 to 18.8 ± 0.4 m·s in the SET group after the training period (p < 0.01), but was unchanged in the control group (17.1 ± 0.4 vs. 16.9 ± 0.4 m·s). These results suggest that core stability training using unstable, closed kinetic chain movements can significantly improve maximal throwing velocity. A stronger and more stable lumbopelvic-hip complex may contribute to higher rotational velocity in multisegmental movements. Strength coaches can incorporate exercises exposing the joints for destabilization force during training in closed kinetic chain exercises. This may encourage an effective neuromuscular pattern and increase force production and can improve a highly specific performance task such as throwing.

Australian Football League concussion guidelines: what do community players think?

PubMed

White, Peta E; Donaldson, Alex; Sullivan, S John; Newton, Joshua; Finch, Caroline F

2016-01-01

Preventing concussion in sport is a global challenge. To assess community-level adult male Australian Football players' views on following the Australian Football League's (AFL) concussion guidelines. 3 focus groups, each comprising 6 players from 1 regional league, were conducted until saturation of issues raised. Discussions followed a semistructured script and were audio-recorded and transcribed verbatim. Thematic analysis was conducted by 2 coders independently. Identified advantages of the guidelines included highlighting the seriousness of concussion; changing the culture around playing with concussion and shifting return-to-play decision responsibility from players to others. Disadvantages included players being removed from play unnecessarily; removal of players' rights to decide if they are fit to play and players changing their behaviours to avoid being removed from play. Identified facilitators to guideline use included local league enforcement; broad information dissemination and impartial medically trained staff to assess concussion. Identified barriers to guideline use included players' desire to play at all costs; external pressure that encouraged players to return to play prematurely; and inconvenience and cost. Players generally understand that the AFL concussion guidelines protect their long-term welfare. However, their desire to play at all costs and help their team win is a common barrier to reporting concussion and adhering to guidelines. Leagues should take a lead role by mandating and enforcing the use of the guidelines and educating coaches, game day medical providers and players. The return-to-play component of the guidelines is complex and needs further consideration in the context of community sport.

Relationships Between the Yo-Yo Intermittent Recovery Test and Anaerobic Performance Tests in Adolescent Handball Players

PubMed Central

Hermassi, Souhail; Aouadi, Ridha; Khalifa, Riadh; van den Tillaar, Roland; Shephard, Roy J.; Chelly, Mohamed Souhaiel

2015-01-01

The aim of the present study was to investigate relationships between a performance index derived from the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) and other measures of physical performance and skill in handball players. The other measures considered included peak muscular power of the lower limbs (Wpeak), jumping ability (squat and counter-movement jumps (SJ, CMJ), a handball skill test and the average sprinting velocities over the first step (VS) and the first 5 m (V5m). Test scores for 25 male national-level adolescent players (age: 17.2 ± 0.7 years) averaged 4.83 ± 0.34 m·s−1 (maximal velocity reached at the Yo-Yo IR1); 917 ± 105 Watt, 12.7 ± 3 W·kg−1 (Wpeak); 3.41 ± 0.5 m·s−1 and 6.03 ± 0.6 m·s−1 (sprint velocities for Vs and V5m respectively) and 10.3 ± 1 s (handball skill test). Yo-Yo IR1 test scores showed statistically significant correlations with all of the variables examined: Wpeak (W and W·kg−1) r = 0.80 and 0.65, respectively, p≤0.001); sprinting velocities (r = 0.73 and 0.71 for VS and V5m respectively; p≤0.001); jumping performance (SJ: r = 0.60, p≤0.001; CMJ: r= 0.66, p≤0.001) and the handball skill test (r = 0.71; p≤0.001). We concluded that the Yo-Yo test score showed a sufficient correlation with other potential means of assessing handball players, and that intra-individual changes of Yo-Yo IR1 score could provide a useful composite index of the response to training or rehabilitation, although correlations lack sufficient precision to help in players’ selection. PMID:25964822

Measured and perceived indices of fluid balance in professional athletes. The use and impact of hydration assessment strategies.

PubMed

Love, T D; Baker, D F; Healey, P; Black, K E

2018-04-01

To determine athletes perceived and measured indices of fluid balance during training and the influence of hydration strategy use on these parameters. Thirty-three professional rugby union players completed a 120 minute training session in hot conditions (35°C, 40% relative humidity). Pre-training hydration status, sweat loss, fluid intake and changes in body mass (BM) were obtained. The use of hydration assessment techniques and players perceptions of fluid intake and sweat loss were obtained via a questionnaire. The majority of players (78%) used urine colour to determine pre-training hydration status but the use of hydration assessment techniques did not influence pre-training hydration status (1.025 ± 0.005 vs. 1.023 ± 0.013 g . ml -1 , P = .811). Players underestimated sweat loss (73 ± 17%) to a greater extent than fluid intake (37 ± 28%) which resulted in players perceiving they were in positive fluid balance (0.5 ± 0.8% BM) rather than the measured negative fluid balance (-1.0 ± 0.7% BM). Forty-eight percent of players used hydration monitoring strategies during exercise but no player used changes in BM to help guide fluid replacement. Players have difficulty perceiving fluid intake and sweat loss during training. However, the use of hydration monitoring techniques did not affect fluid balance before or during training.

Tactical expertise assessment in youth football using representative tasks.

PubMed

Serra-Olivares, Jaime; Clemente, Filipe Manuel; González-Víllora, Sixto

2016-01-01

Specific football drills improve the development of technical/tactical and physical variables in players. Based on this principle, in recent years it has been possible to observe in daily training a growing volume of small-sided and conditioned games. These games are smaller and modified forms of formal games that augment players' perception of specific tactics. Despite this approach, the assessment of players' knowledge and tactical execution has not been well documented, due mainly to the difficulty in measuring tactical behavior. For that reason, this study aims to provide a narrative review about the tactical assessment of football training by using representative tasks to measure the tactical expertise of youth football players during small-sided and conditioned games. This study gives an overview of the ecological approach to training and the principles used for representative task design, providing relevant contribution and direction for future research into the assessment of tactical expertise in youth football.

On the complexity of classical guitar playing: functional adaptations to task constraints.

PubMed

Heijink, Hank; Meulenbroek, Ruud G J

2002-12-01

The authors performed a behavioral study of the complexity of left-hand finger movements in classical guitar playing. Six professional guitarists played movement sequences in a fixed tempo. Left-hand finger movements were recorded in 3 dimensions, and the guitar sound was recorded synchronously. Assuming that performers prefer to avoid extreme joint angles when moving, the authors hypothesized 3 complexity factors. The results showed differential effects of the complexity factors on the performance measures and on participants' judgments of complexity. The results demonstrated that keeping the joints in the middle of their range is an important principle in guitar playing, and players exploit the available tolerance in timing and placement of the left-hand fingers to control the acoustic output variability.

Increasing motivation in robot-aided arm rehabilitation with competitive and cooperative gameplay

PubMed Central

2014-01-01

Background Several strategies have been proposed to improve patient motivation and exercise intensity during robot-aided stroke rehabilitation. One relatively unexplored possibility is two-player gameplay, allowing subjects to compete or cooperate with each other to achieve a common goal. In order to explore the potential of such games, we designed a two-player game played using two ARMin arm rehabilitation robots. Methods The game was an air-hockey task displayed on a computer monitor and controlled using shoulder movements in the ARMin robot. Three game modes were tested: single-player (competing against computer), competitive (competing against human), and cooperative (cooperating with human against computer). All modes were played by 30 unimpaired subjects and 8 impaired chronic stroke subjects. The subjects filled out the Intrinsic Motivation Inventory questionnaire after each game mode, as well as a final questionnaire about game preferences and their personality. Results Nearly all unimpaired subjects preferred playing the two-player game modes to the single-player one, as they enjoyed talking and interacting with another person. However, there were two distinct player groups: one liked the competitive mode but not the cooperative mode while the other liked the cooperative but not the competitive mode. Unimpaired subjects who liked the competitive mode also put significantly more effort into it than into the other modes. Results from impaired subjects were similar, with even impaired subjects over 60 years old enjoying competitive gameplay. The subjects’ personalities roughly predicted which mode they would prefer, which was especially evident in a poorly-matched impaired pair that preferred the single-player mode. Conclusions Results indicate great potential for two-player rehabilitation games, in the form of greater enjoyment as well as potentially more intensive exercise compared to single-player games. However, the right game type needs to be chosen for each subject depending on skill and personality, along with selecting an appropriate co-player. Further studies with patients that are currently enrolled in rehabilitation programs are recommended, and the subjective measures used in our study should be augmented with objective measures such as electromyography. PMID:24739255

Increasing motivation in robot-aided arm rehabilitation with competitive and cooperative gameplay.

PubMed

Novak, Domen; Nagle, Aniket; Keller, Urs; Riener, Robert

2014-04-16

Several strategies have been proposed to improve patient motivation and exercise intensity during robot-aided stroke rehabilitation. One relatively unexplored possibility is two-player gameplay, allowing subjects to compete or cooperate with each other to achieve a common goal. In order to explore the potential of such games, we designed a two-player game played using two ARMin arm rehabilitation robots. The game was an air-hockey task displayed on a computer monitor and controlled using shoulder movements in the ARMin robot. Three game modes were tested: single-player (competing against computer), competitive (competing against human), and cooperative (cooperating with human against computer). All modes were played by 30 unimpaired subjects and 8 impaired chronic stroke subjects. The subjects filled out the Intrinsic Motivation Inventory questionnaire after each game mode, as well as a final questionnaire about game preferences and their personality. Nearly all unimpaired subjects preferred playing the two-player game modes to the single-player one, as they enjoyed talking and interacting with another person. However, there were two distinct player groups: one liked the competitive mode but not the cooperative mode while the other liked the cooperative but not the competitive mode. Unimpaired subjects who liked the competitive mode also put significantly more effort into it than into the other modes. Results from impaired subjects were similar, with even impaired subjects over 60 years old enjoying competitive gameplay. The subjects' personalities roughly predicted which mode they would prefer, which was especially evident in a poorly-matched impaired pair that preferred the single-player mode. Results indicate great potential for two-player rehabilitation games, in the form of greater enjoyment as well as potentially more intensive exercise compared to single-player games. However, the right game type needs to be chosen for each subject depending on skill and personality, along with selecting an appropriate co-player. Further studies with patients that are currently enrolled in rehabilitation programs are recommended, and the subjective measures used in our study should be augmented with objective measures such as electromyography.

Comparison of Ball-And-Racket Impact Force in Two-Handed Backhand Stroke Stances for Different-Skill-Level Tennis Players.

PubMed

Lo, Kuo-Cheng; Hsieh, Yung-Chun

2016-06-01

This study compared the kinetic roles of the upper extremities in racket impact force generation between the open stance (OS) and square stance (SS) for tennis players with different skill levels in two-handed backhand strokes. Twelve male tennis players were divided into an advanced group (AG) (L3-L2 skill level) and intermediate group (IG) (L7-L6 skill level), and their data were used in a three-dimensional kinetic analysis. Their motions were captured using 21 reflective markers attached to anatomic landmarks for two-handed backhand stroke motion data collection. During the acceleration phase, significant differences were not observed between both stances, but they were observed between the groups with different skill levels for the force of the upper extremities (p = 0.027). The joint forces were significantly lower in the AG than in the IG. Players performing the SS had significantly larger pronation and supination of the wrist joint moment than those in the OS (p = 0.032) during the acceleration phase, irrespective of the playing level. Higher internal rotation moment after impact was observed at each joint, particularly among young intermediate tennis players, regardless of their stance. The AG demonstrated a higher joint force and moment at every joint compared with the IG at impact. Moreover, the AG demonstrated superior stroke efficiency and effectively reduced joint moment after impact and sports injury. Key pointsAdvanced players, regardless of open stance or square stance, have larger joint force and moment at each joint before ball impact resulting in better stroke efficiency and reduced chance of injury.Intermediate players, regardless of stance, have higher internal rotation moment at each joint instead of larger joint force as compared to advanced players before ball impact. The higher internal rotation moment will induce higher joint impact force which makes the player injury-prone.Young intermediate tennis players may want to avoid excessive follow-through movement after ball impact to prevent injury in their early career.

Influence of Pokémon Go on physical activity levels of university players: a cross-sectional study.

PubMed

Wong, Fiona Y

2017-02-22

The prevalence of overweight is increasing and the effectiveness of various weight management and exercise programs varied. An augmented reality smartphone game, Pokémon Go, appears to increase activity levels of players. This study assessed the players and ex-players' frequencies and durations of staying outdoors, and walking/jogging before and during the time they played Pokémon Go, evaluated the physical activity levels of players, ex-players and non-players, and investigated the potential factors which determined their play statuses. Students in a university answered an online-questionnaire survey. The IPAQ-short form was incorporated to measure vigorous-intensity activities, moderate-intensity activities and walking. Chi square tests were used to compare frequencies and durations of staying outdoors and walking/jogging, health discomforts and physical activity levels between players, ex-players and non-players. Wilcoxon signed ranks tests were performed to assess the changes prior to and during the time when the players and ex-players played Pokémon Go. Logistic regression analyses were performed to assess factors contributing to playing, quitting or not playing Pokémon Go. 644 university students answered the questionnaire. Compared with the ex-players, the players were significantly more frequent to stay outdoors when playing Pokémon Go (P < 0.001), walk/jog to a location to catch Pokémon, to Pokéstops or Gyms (P < 0.005), as well as walking/jogging to hatch eggs (P < 0.001). Players who never or rarely walked/jogged before spent a mean of 108.19 ± 158.21 min/week to walk/jog in order to play the game which is equivalent to burning 357 kcal/week for a 60-kg person walking a moderate pace. Compared with the non-players, players were more likely to be aged 18-25 years [OR (95% CI) 3.28 (1.28-8.40), P = 0.013], never [OR (95% CI) 10.51 (1.12-98.57), P = 0.039] or rarely [OR (95% CI) 4.00 (1.95-8.23), P < 0.001] stayed outdoors and rarely walked/jogged prior to playing the game [OR (95% CI) 3.88 (1.86-8.05), P < 0.001]. However, there was no significant difference in physical activity levels between the three groups (P = 0.573). Players who used to be sedentary benefited the most from Pokémon Go. The game can be used as a starting point for sedentary people to begin an active lifestyle. The impact of Pokémon Go on physical activity can provide insights to public health workers in using novel strategies in health promotion.

Sensitivity of monthly heart rate and psychometric measures for monitoring physical performance in highly trained young handball players.

PubMed

Buchheit, M

2015-05-01

The aim of the present study was to examine whether monthly resting heart rate (HR), HR variability (HRV) and psychometric measures can be used to monitor changes in physical performance in highly-trained adolescent handball players. Data were collected in 37 adolescent players (training 10±2.1 h.wk(-1)) on 11 occasions from September to May during the in-season period, and included an estimation of training status (resting HR and HRV, the profile of mood state (POMS) questionnaire), and 3 physical performance tests (a 10-m sprint, a counter movement jump and a graded aerobic intermittent test, 30-15 Intermittent Fitness Test). The sensitivity of HR and psychometric measures to changes in physical performance was poor (< 20%), irrespective of the training status markers and the performance measures. The specificity was however strong (> 75%), irrespective of the markers and the performance measures. Finally, the difference in physical performance between players with better vs. worse estimated training status were all almost certainly trivial. The present results highlight the limitation of monthly measures of resting HR, HRV and perceived mood and fatigue for predicting in-season changes in physical performance in highly-trained adolescent handball players. This suggests that more frequent monitoring might be required, and/or that other markers might need to be considered. © Georg Thieme Verlag KG Stuttgart · New York.

Use of the King-Devick test for sideline concussion screening in junior rugby league.

PubMed

King, D; Hume, P; Gissane, C; Clark, T

2015-10-15

To determine whether the King-Devick (K-D) test used as a sideline test in junior rugby league players over 12 matches in a domestic competition season could identify witnessed and incidentally identified episodes of concussion. A prospective observational cohort study of a club level junior rugby league team (n=19) during the 2014 New Zealand competition season involved every player completing two pre-competition season baseline trials of the K-D test. Players removed from match participation, or who reported any signs or symptoms of concussion were assessed on the sideline with the K-D test and referred for further medical assessment. Players with a pre- to post-match K-D test difference >3s were referred for physician evaluation. The baseline test-retest reliability of the K-D test was high (rs=0.86; p<0.0001). Seven concussions were medically identified in six players who recorded pre- to post-match K-D test times greater than 3s (mean change of 7.4s). Post-season testing of players demonstrated improvement of K-D time scores consistent with learning effects of using the K-D test (67.7s vs. 62.2s). Although no witnessed concussions occurred during rugby play, six players recorded pre- to post-match changes with a mean delay of 4s resulting in seven concussions being subsequently confirmed post-match by health practitioners. All players were medically managed for a return to sports participation. The K-D test was quickly and easily administered making it a practical sideline tool as part of the continuum of concussion assessment tools for junior rugby league players. Copyright © 2015 Elsevier B.V. All rights reserved.

The Development and Evaluation of an Online Formative Assessment upon Single-Player Game in E-Learning Environment

ERIC Educational Resources Information Center

Tsai, Fu-Hsing

2013-01-01

This study developed a game-based formative assessment, called tic-tac-toe quiz for single-player version (TRIS-Q-SP), in an energy education e-learning system. This assessment game combined tic-tac-toe with online assessment, and revised the rule of tic-tac-toe for stimulating students to use online formative assessment actively. Additionally, to…

"Don't worry, it's just poker!"--experience, self-rumination and self-reflection as determinants of decision-making in on-line poker.

PubMed

Palomäki, Jussi; Laakasuo, Michael; Salmela, Mikko

2013-09-01

On-line poker is a game of chance and skill. The construct of poker playing skill has both a technical (game strategy-related) and an emotional (emotion regulation-related) aspect. A correlational on-line study (N = 354) was conducted to assess differences in technical skills and emotional characteristics related to poker playing style between experienced and inexperienced poker players. Results suggest that, with respect to emotional characteristics, experienced poker players engage in less self-rumination and more self-reflection, as compared to inexperienced players. Experienced poker players are also able to make better decisions, by mathematical standards, in a poker decision-making environment, as assessed by two fictitious on-line poker decision-making scenarios. Furthermore, this study provides supportive evidence that experienced poker players conceptualize the construct of "luck" differently from inexperienced players. A new poker playing experience scale (PES) for accurately measuring poker playing experience is presented in this paper.

Left-handed skeletally mature baseball players have smaller humeral retroversion in the throwing arm than right-handed players.

PubMed

Takenaga, Tetsuya; Goto, Hideyuki; Sugimoto, Katsumasa; Tsuchiya, Atsushi; Fukuyoshi, Masaki; Nakagawa, Hiroki; Nozaki, Masahiro; Takeuchi, Satoshi; Otsuka, Takanobu

2017-12-01

It is known that the humeral retroversion of baseball players is greater in the throwing arm than in the nonthrowing arm. An investigation measuring dry bone specimens also showed that the right humerus had greater retroversion than the left. Considering these facts, it was hypothesized that humeral retroversion would differ between right- and left-handed players. This study aimed to compare the bilateral humeral retroversion between right- and left-handed skeletally mature baseball players. We investigated 260 (196 right-handed and 64 left-handed) male baseball players who belonged to a college or amateur team. Bilateral humeral retroversion was assessed using an ultrasound-assisted technique (humeral torsion angle [HTA]) as described by previous studies. Analysis of covariance, adjusted for handedness and baseball position, assessed the effect of throwing arm dominance on HTA. In comparison of the throwing arm, HTA was significantly smaller in left-handed (left humerus) than in right-handed (right humerus) players (77° vs. 81°; P < .001). In comparison of the nonthrowing arm, HTA was significantly greater in left-handed (right humerus) than in right-handed (left humerus) players (73° vs. 69°; P < .001). The mean side-to-side difference of HTA was significantly smaller in left-handed than in right-handed players (3° vs. 12°; P < .001). Humeral retroversion of left-handed skeletally mature baseball players was significantly smaller in the throwing arm, greater in the nonthrowing arm, and smaller in side-to-side differences than that of right-handed players. These findings may be key to understanding some of the biomechanical differences between right- and left-handed baseball players. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Differences in the bioenergetic potential of athletes participating in team sports.

PubMed

Malacko, Julijan; Doder, Dragan; Djurdjević, Slavisa; Savić, Biljana; Doder, Radoslava

2013-07-01

In modern training technology, assessment of aerobic bioenergetic potential in athletes is commonly performed by standard laboratory procedures to determine basic or specific functional abilities for specific sport activity or discipline. The aim of study was to assess the aerobic bioenergetic potential of athletes participating in basketball, football and handball. The study included 87 athletes (29 basketball players, 29 football players, and 29 handball players) aged 21-24. Evaluation of the aerobic bioenergetic potential of athletes participating in basketball, football and handball was performed followed by both univariate (ANOVA) and multivariate (MANOVA) statistical methods to determine differences among the athletes in relative (VO2 mL/kg/min) and absolute oxygen consumption (VO2 L/min). Statistically significant differences between absolute and relative oxygen consumption were found in basketball players (Mb), football players (Mf), and handball players (Mh) (MANOVA, p = 0.00). ANOVA also revealed significant differences in relative oxygen consumption (VO2 mL/kg/min) (p = 0.00). The football players (55.32 mL/kg/min) had the highest relative oxygen consumption, followed by the handball players (51.84 mL/kg/min) and basketball players (47.00 mL/kg/min). The highest absolute oxygen consumption was recorded in the basketball players (4.47 L/min), followed by the handball players (4.40 L/min) and footballers (4.16 L/min). Statistically significant differences in the aerobic bioenergetic potential, expressed by the relative oxygen consumption were found among atletes participating in different team sports. It can be assumed that the player from the sports in which it is necessary to cross greater distance in total during the match have a greater need for aerobic capacity.

Set as an instance of a real-world visual-cognitive task.

PubMed

Nyamsuren, Enkhbold; Taatgen, Niels A

2013-01-01

Complex problem solving is often an integration of perceptual processing and deliberate planning. But what balances these two processes, and how do novices differ from experts? We investigate the interplay between these two in the game of SET. This article investigates how people combine bottom-up visual processes and top-down planning to succeed in this game. Using combinatorial and mixed-effect regression analysis of eye-movement protocols and a cognitive model of a human player, we show that SET players deploy both bottom-up and top-down processes in parallel to accomplish the same task. The combination of competition and cooperation of both types of processes is a major factor of success in the game. Finally, we explore strategies players use during the game. Our findings suggest that within-trial strategy shifts can occur without the need of explicit meta-cognitive control, but rather implicitly as a result of evolving memory activations. Copyright © 2012 Cognitive Science Society, Inc.

Draft-camp predictors of subsequent career success in the Australian Football League.

PubMed

Burgess, Darren; Naughton, Geraldine; Hopkins, Will

2012-11-01

The National Draft Camp results are generally considered to be important for informing talent scouts about the physical performance capacities of talented young Australian Rules Football (AFL) players. The purpose of this project was to determine magnitude of associations between five year career success in the AFL and physical draft camp tests, final draft selection order and previous match physical performance. Physical testing data of 99 players from the National Under 18 (U 18) competition were retrospectively analysed across 2002 and 2003 National Draft Camps. Physical match data was collected on these players and links with subsequent early career success (AFL games played) were explored. TrakPerformance Software was used to quantify the movement of 92 players during competitive games of the National U 18 Championships. Linear modelling using results from draft camp data involving 95 U 18 players, along with final draft selection order, was used to predict five year career success in senior AFL. Multiple U 18 match variables demonstrated large associations (sprints/min=43% more games, % sprint=43% more games) with five year career success in AFL. Final draft order and single variable predictors had moderate associations with career success. Neither U 18 matches nor draft camp testing was predictive of injuries incurring over the five years. Variability in senior AFL career success had a large association with a combination of match physical variables and draft test results. The objective data available should be considered in the selection of prospective player success. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Distinct eye movement patterns enhance dynamic visual acuity.

PubMed

Palidis, Dimitrios J; Wyder-Hodge, Pearson A; Fooken, Jolande; Spering, Miriam

2017-01-01

Dynamic visual acuity (DVA) is the ability to resolve fine spatial detail in dynamic objects during head fixation, or in static objects during head or body rotation. This ability is important for many activities such as ball sports, and a close relation has been shown between DVA and sports expertise. DVA tasks involve eye movements, yet, it is unclear which aspects of eye movements contribute to successful performance. Here we examined the relation between DVA and the kinematics of smooth pursuit and saccadic eye movements in a cohort of 23 varsity baseball players. In a computerized dynamic-object DVA test, observers reported the location of the gap in a small Landolt-C ring moving at various speeds while eye movements were recorded. Smooth pursuit kinematics-eye latency, acceleration, velocity gain, position error-and the direction and amplitude of saccadic eye movements were linked to perceptual performance. Results reveal that distinct eye movement patterns-minimizing eye position error, tracking smoothly, and inhibiting reverse saccades-were related to dynamic visual acuity. The close link between eye movement quality and DVA performance has important implications for the development of perceptual training programs to improve DVA.

Distinct eye movement patterns enhance dynamic visual acuity

PubMed Central

Palidis, Dimitrios J.; Wyder-Hodge, Pearson A.; Fooken, Jolande; Spering, Miriam

2017-01-01

Dynamic visual acuity (DVA) is the ability to resolve fine spatial detail in dynamic objects during head fixation, or in static objects during head or body rotation. This ability is important for many activities such as ball sports, and a close relation has been shown between DVA and sports expertise. DVA tasks involve eye movements, yet, it is unclear which aspects of eye movements contribute to successful performance. Here we examined the relation between DVA and the kinematics of smooth pursuit and saccadic eye movements in a cohort of 23 varsity baseball players. In a computerized dynamic-object DVA test, observers reported the location of the gap in a small Landolt-C ring moving at various speeds while eye movements were recorded. Smooth pursuit kinematics—eye latency, acceleration, velocity gain, position error—and the direction and amplitude of saccadic eye movements were linked to perceptual performance. Results reveal that distinct eye movement patterns—minimizing eye position error, tracking smoothly, and inhibiting reverse saccades—were related to dynamic visual acuity. The close link between eye movement quality and DVA performance has important implications for the development of perceptual training programs to improve DVA. PMID:28187157

Conducting Expressively: Navigating Seven Misconceptions That Inhibit Meaningful Connection to Ensemble and Sound

ERIC Educational Resources Information Center

Snyder, Courtney

2016-01-01

When expressivity (ignited by imagination) is incorporated into the learning process for both the conductor (teacher) and player (student), the qualities of movement, communication, instruction, and ensemble sound all change for the better, often with less work. Expressive conducting allows the conductor to feel more connected to the music and the…

Integration of Active Video Games in Extracurricular Activity at Schools

ERIC Educational Resources Information Center

Lee, Jung Eun; Huang, Charles; Pope, Zachary; Gao, Zan

2015-01-01

Active video games require players to be physically active. Dance Dance Revolution (DDR) is an interactive dancing game that requires fast-foot movement coordinated with energetic music and visuals. The Wii and Xbox Kinect games have also become good active video games for the promotion of physical activity participation. These games are much more…

Are professional handball players at risk for developing a glenohumeral internal rotation deficit in their dominant arm?

PubMed

Seabra, Pedro; Van Eck, Carola F; Sá, Márcia; Torres, João

2017-05-01

Overhead athletes, such as baseball players, have been shown to have adaptive changes in the shoulder range of motion (ROM) of their dominant arm. Professional handball players are a unique subtype of overhead athletes with very different demands from baseball players. The aim of this study was to determine if professional handball players demonstrate differences in shoulder ROM between their dominant and non-dominant arm and try to relate them with new variables. Fifty professional male handball players were included and completed a questionnaire regarding age at which they started to play, number of hours they practice a week, field position and arm dominance. ROM measurements were performed including forward flexion (FF), external rotation with the shoulder in abduction (ABER) and with adducted arm (ADER) and internal rotation with shoulder in abduction (IR). Statistical analysis was performed to determine differences in ROM between the dominant and non-dominant shoulder and if there is a relationship between these differences and shoulder load or field position. The dominant arm showed decreased internal rotation (47 vs. 56 degrees, p < 0.001) and increased external rotation both with the arm abducted (99 vs. 88 degrees, p < 0.001) and at the side (62 vs 57 degrees, p = 0.001). This was not correlated with shoulder load for any movement (FF, p = 0.980; ABER, p = 0.741; ADER, p = 0.803; IR, p = 0.085) but was dependent on field position with first line players showing the highest internal rotation deficit (13 degrees vs. 6-7 degrees in the other field positions, p = 0.013). This study showed that professional male handball players with a first line position have a significant risk for developing a glenohumeral internal rotation deficit, similar to the phenomenon seen in baseball pitchers.

Comparison of the Physical and Technical Demands of Cricket Players During Training and Match-Play.

PubMed

Vickery, Will; Duffield, Rob; Crowther, Rian; Beakley, David; Blanch, Peter; Dascombe, Ben J

2018-03-01

Vickery, W, Duffield, R, Crowther, R, Beakley, D, Blanch, P, and Dascombe, BJ. Comparison of the physical and technical demands of cricket players during training and match-play. J Strength Cond Res 32(3): 821-829, 2018-This study aimed to determine which training method (net-based sessions or center-wicket simulations) currently used in national level and U19 male players cricket provided a more physical and technical match-specific training response. The heart rate, rating of perceived exertion, and movement patterns of 42 male cricket players were measured across the various training and match formats. Video analysis was coded retrospectively to quantify technical loads based on the cricket skills performed. Magnitude-based inferences were based on the standardization of effect and presented with ±90% confidence intervals. Regardless of playing position, differences in physiological demands between training modes and match-play were unclear, with the exception of higher heart rates in fielders during traditional net sessions (mean heart rate: d = -2.7 [-4.7 to -0.7]; 75% of maximum heart rate: d = -1.7 [-3.2 to -0.2]). Typically, the movement demands of center-wicket simulations were similar or greater than match-play, which was most evident in the distance traveled at a high intensity within each playing position (batsmen: d = 6.4 [3.7-9.2]; medium-fast bowlers: d = 1.71 [0.1-3.3]; spin bowlers: d = 6.5 [0.01-13.0]; fielders: d = 0.8 [-0.2 to 1.7]). The technical demands of traditional net cricket training exceeded that of a typical match for each playing position. Specifically, fast bowlers delivered a greater number of balls during net-bowling compared with a match (d = -2.2 [-3.6 to 0.9]). In conclusion, center-wicket simulations more closely matched the physical demands of a One-Day match within batsmen and spin bowlers, whereas traditional cricket training often exceeded match-specific demands.

The World (of Warcraft) through the eyes of an expert.

PubMed

Marzouki, Yousri; Dusaucy, Valériane; Chanceaux, Myriam; Mathôt, Sebastiaan

2017-01-01

Negative correlations between pupil size and the tendency to look at salient locations were found in recent studies (e.g., Mathôt et al., 2015). It is hypothesized that this negative correlation might be explained by the mental effort put by participants in the task that leads in return to pupil dilation. Here we present an exploratory study on the effect of expertise on eye-movement behavior. Because there is no available standard tool to evaluate WoW players' expertise, we built an off-game questionnaire testing players' knowledge about WoW and acquired skills through completed raids, highest rated battlegrounds, Skill Points, etc. Experts ( N  = 4) and novices ( N  = 4) in the massively multiplayer online role-playing game World of Warcraft (WoW) viewed 24 designed video segments from the game that differ in regards with their content (i.e, informative locations) and visual complexity (i.e, salient locations). Consistent with previous studies, we found a negative correlation between pupil size and the tendency to look at salient locations (experts, r  =  - .17, p  < .0001, and novices, r  =  - .09, p  < .0001). This correlation has been interpreted in terms of mental effort: People are inherently biased to look at salient locations (sharp corners, bright lights, etc.), but are able (i.e., experts) to overcome this bias if they invest sufficient mental effort. Crucially, we observed that this correlation was stronger for expert WoW players than novice players ( Z  =  - 3.3, p  = .0011). This suggests that experts learned to improve control over eye-movement behavior by guiding their eyes towards informative, but potentially low-salient areas of the screen. These findings may contribute to our understanding of what makes an expert an expert.

Dissecting the links between cerebellum and dystonia.

PubMed

Malone, Ailish; Manto, Mario; Hass, Chris

2014-12-01

Dystonia is a common movement disorder characterized by sustained muscle contractions. These contractions generate twisting and repetitive movements or typical abnormal postures, often exacerbated by voluntary movement. Dystonia can affect almost all the voluntary muscles. For several decades, the discussion on the pathogenesis has been focused on basal ganglia circuits, especially striatal networks. So far, although dystonia has been observed in some forms of ataxia such as dominant ataxias, the link between the cerebellum and dystonia has remained unclear. Recent human studies and experimental data mainly in rodents show that the cerebellum circuitry could also be a key player in the pathogenesis of some forms of dystonia. In particular, studies based on behavioral adaptation paradigm shed light on the links between dystonia and cerebellum. The spectrum of movement disorders in which the cerebellum is implicated is continuously expanding, and manipulation of cerebellar circuits might even emerge as a candidate therapy in the coming years.

Exploring children's movement characteristics during virtual reality video game play.

PubMed

Levac, Danielle; Pierrynowski, Michael R; Canestraro, Melissa; Gurr, Lindsay; Leonard, Laurean; Neeley, Christyann

2010-12-01

There is increasing interest in the use of commercially-available virtual reality video gaming systems within pediatric rehabilitation, yet little is known about the movement characteristics of game play. This study describes quantity and quality of movement during Nintendo Wii and Wii Fit game play, explores differences in these movement characteristics between games and between novice and experienced players, and investigates whether motivation to succeed at the game impacts movement characteristics. Thirty-eight children (aged 7-12) with and without previous game experience played Wii (boxing and tennis) and Wii Fit (ski slalom and soccer heading) games. Force plate data provided center of pressure displacement (quantity) and processed pelvis motion indicated smoothness of pelvic movement (quality). Children rated their motivation to succeed at each game. Movement quantity and quality differed between games (p<.001). Children with previous experience playing Wii Fit games demonstrated greater movement quantity during Wii Fit game play (p<.001); quality of movement did not differ between groups. Motivation to succeed did not influence the relationship between experience and outcomes. Findings enhance clinical understanding of this technology and inform the development of research questions to explore its potential to improve movement skills in children with motor impairments. Copyright © 2010 Elsevier B.V. All rights reserved.

Space occupation near the basket shapes collective behaviours in youth basketball.

PubMed

Esteves, Pedro T; Silva, Pedro; Vilar, Luís; Travassos, Bruno; Duarte, Ricardo; Arede, Jorge; Sampaio, Jaime

2016-08-01

This study aimed to analyse how youth basketball players explored numerical overloads during shot attempts by measuring their space occupation across specific court areas. Four process-tracing variables measured how the number of attackers (NA), number of defenders (ND), interpersonal distance between attacker and the closest defender (ID) and distance between attacker and the basket (DBkt) impacted on the performance outcome (converted shot; missed shot; ball possession lost). Ten competitive games involving 13 U14 teams were video recorded and players' displacements were digitised. The associations between performance outcomes and the process-tracing measures were assessed using standardised mean differences and a cross-correlation function. A multinomial logistic regression was used to calculate the odds ratio (OR) for each of the three possible outcomes. Results revealed that when shot attempts occurred at larger ID and at smaller DBkt, the possibilities to obtain a converted shot increased. The numerical overload of defenders near the scoring target was predominantly associated with offensive success. Also, the possibility of attackers to lead the spatial relation of movements with the defenders, near the scoring target, appeared as a prominent strategy to succeed. In sum, basketball teams that exhibit potential to adapt their collective behaviours to local changes in the environment might be closer to achieving successful outcomes.

Fluctuations in Activity Demands Across Game Quarters in Professional and Semiprofessional Male Basketball.

PubMed

Scanlan, Aaron T; Tucker, Patrick S; Dascombe, Ben J; Berkelmans, Daniel M; Hiskens, Matthew I; Dalbo, Vincent J

2015-11-01

Examination of activity demands and stoppage durations across game periods provides useful insight concerning fatigue, tactical strategies, and playing pace in team sports such as basketball. Therefore, the aims of this study were to quantify and compare game activity fluctuations across quarters in professional and semiprofessional basketball players. Video-based time-motion analyses were conducted across multiple games. Frequencies, total durations (in seconds), total distances (in meters), and mean velocities (in meters per second) were calculated for low-intensity movement (≤3 m·s), high-intensity movement (>3 m·s), shuffling, and dribbling activity. Frequencies were determined for jumping and upper-body activity; stoppage durations were also calculated. Separate repeated-measures analysis of variance and Cohen's d were used to identify significant differences and quantify the effect sizes between game quarters for all outcome measures, respectively. Pearson correlation analyses were performed to determine the relationship between stoppage duration and all activity measures. The results showed significantly (p ≤ 0.05) reduced dribbling (3.09 ± 0.03 m·s vs. 2.81 ± 0.01 m·s) and total (2.22 ± 0.04 m·s vs. 2.09 ± 0.03 m·s) activity velocities during the third compared with the first quarter in professional players. Furthermore, effect size analyses showed greater decreases in high-intensity (professional: d = 1.7-5.4; semiprofessional: d = 0.3-1.7), shuffling (professional: d = 2.3-3.2; semiprofessional: d = 1.4-2.1), and total (professional: d = 1.0-4.9; semiprofessional: d = 0.3-0.8) activity and increases in dribbling (professional: d = 1.4-4.7; semiprofessional: d = 2.5-2.8) with game progression in professional players. In semiprofessional players, stoppage duration was significantly (p ≤ 0.05) related to various low-intensity (R = 0.64-0.72), high-intensity (R = 0.65-0.72), and total (R = 0.63-0.73) activity measures. Although not directly measured, the observed game activity fluctuations were likely because of a combination of physiological (e.g., muscle glycogen depletion, dehydration), tactical (e.g., ball control, game pace), and game-related (e.g., time-outs, player fouls) factors. Basketball coaches can use the provided data to (a) develop more precise training plans and management strategies, (b) elevate semiprofessional player performance closer to the professional level, and (c) incorporate tactical strategies to maximize the benefits of stoppages.

Magnetic Resonance Imaging Findings in the Symptomatic Hips of Younger Retired National Football League Players.

PubMed

Domb, Benjamin G; Jackson, Timothy J; Carter, Christopher C; Jester, Jon R; Finch, Nathan A; Stake, Christine E

2014-07-01

American football players have an increased level of risk for hip injuries because of the high level of contact, biomechanical load, and anatomic strain placed on the hip joint. Many injuries are attributed to soft tissue injury rather than intra-articular lesions. However, because of improved imaging and increased knowledge, physicians are attributing unexplained hip pain to intra-articular lesions with increasing frequency. To assess the prevalence of pathologic intra-articular hip lesions in a younger, retired National Football League (NFL) player cohort evaluated for persistent hip pain. Case series; Level of evidence, 4. A retrospective chart review was performed of magnetic resonance imaging (MRI) on retired NFL players evaluated at an orthopaedic clinic for persistent hip pain. All MRIs were performed at the same location and reviewed by the same independent radiologist. The study included 62 hips; MRI was used to evaluate 27 hips, and MRI arthrogram was used to evaluate 35 hips. Images were assessed for labral tears, chondral lesions, ligamentum teres (LT) tears, bone cysts, osteophytes, loose bodies, trochanteric bursitis, and alpha angle. Player demographics, including position and seasons played, were recorded. From February 2011 to December 2012, a total of 50 retired players from the NFL (average age, 33 years; range, 27-39 years) received impairment evaluations assessing all symptomatic joints. Thirty-eight (76%) players had hip complaints and underwent a dedicated hip MRI. Twenty-four players (63%) had bilateral hip pain, for a total of 62 hips evaluated. There were 55 (89%) labral tears, 61 (98%) chondral lesions, and 50 (81%) partial or complete LT tears identified on MRI. Additional findings included 3 (5%) hips with osteophytes, 9 (14.5%) with subchondral bone cysts, and 3 (5%) with paralabral cysts. None of the players were found to have trochanteric bursitis or loose bodies. Fifty-eight of 62 alpha angles could be measured, for a mean of 59° (range, 39°-77°). The majority of players were defensive players (63%), while the remainder were offensive players (34%) and 1 special teams player. Position breakdown was as follows: 29% were defensive backs, 16% played the defensive line, 18% were linebackers, 13% were fullbacks, 11% were wide receivers, 5% played the offensive line, and the remaining 8% were kickers, running backs, and quarterbacks. This study demonstrated a high incidence of intra-articular pathologic lesions of the hip in a younger cohort of retired NFL players. The majority of players had bilateral hip pain. The most common finding was chondral lesions, followed by labral tears. Future research is needed to further elucidate incidence and treatment outcomes using prospective studies examining active and retired players with hip-related injuries. © 2014 The Author(s).

A protocol for the health and fitness assessment of NBA players.

PubMed

Scheller, A; Rask, B

1993-04-01

The assessment of the health and fitness of elite basketball players should be a multidisciplinary process. We have described an organized, efficient, and comprehensive protocol for preseason physical evaluations that could be used at the university as well as professional level.

Standardisation of role players for the Clinical Skills Assessment of the MRCGP.

PubMed

Russell, David; Simpson, Robin; Rendel, Sue

2011-05-01

This paper describes the processes used to prepare the role players who simulate the 'patients' in the MRCGP Clinical Skills Assessment (CSA) examination, one of the licensing qualifications for GPs completing their training. Because it is such a high-stakes exam, the CSA must be seen to be fair and trustworthy, and such attributes could be compromised by inadequate role player performance. On a CSA examination day, three role players simulate the same 'patient' simultaneously on three different exam floors, each playing the same case up to 26 times on the day, and these 'patients' must present in a consistent and reliable manner to ensure that all candidates face the same test situation. The paper describes the initial selection and training of the actors, how they are prepared on the day of the exam itself, and the quality assurance processes designed to ensure that the exam has excellent role players performing as the simulated 'patients'.

A comparison of take-off dynamics during three different spikes, block and counter-movement jump in female volleyball players.

PubMed

Kabacinski, Jaroslae; Dworak, Lecholslaw B; Murawa, Michal; Ostarello, John; Rzepnicka, Agata; Maczynski, Jacek

2016-12-01

The purpose of the study was to compare the take-off dynamics in counter-movement jump (CMJ), volleyball block and spikes. Twelve professional female players, representing the highest volleyball league in Poland, participated in the laboratory tests. A force platform was used to record ground reaction force (GRF) during take-off phase in CMJ test, block from a run-up and spikes: front row attack, slide attack, back row attack. Vertical (v) GRF (peak: Rmax and integral mean: ), impulse of vGRF (J) and mechanical power (peak: Pmax and integral mean:

) were analyzed. Significant differences (P<0.05) of values of the dynamic parameters (Rmax, , J, Pmax, and

) were found between CMJ, block from a run-up and three different technique spikes. The highest values were recorded during take-off in the back row attack: peak vGRF (2.93±0.05 BW), integral mean vGRF (1.90±0.08 BW), impulse of vGRF (354±40 Ns), peak power (5320±918 W) and integral mean power (3604±683 W). Peak power (2608±217 W) and integral mean power (1417±94 W) were determined in CMJ test to evaluate the force-velocity capabilities of the players. In terms of GRF and the mechanical power, high level of dynamics in take-off influences positively the jumping height and significantly increases the effectiveness of attacks during spike of the ball over the block of the opponent.

Anthropometric and physical characteristics allow differentiation of young female volleyball players according to playing position and level of expertise

PubMed Central

Milić, M; Grgantov, Z; Chamari, K; Bianco, A; Padulo, J

2016-01-01

The aim of our study was to determine the differences in some anthropometric and physical performance variables of young Croatian female volleyball players (aged 13 to 15) in relation to playing position (i.e., independent variable) and performance level within each position (i.e., independent variable). Players were categorized according to playing position (i.e., role) as middle blockers (n=28), opposite hitters (n=41), passer-hitters (n=54), setters (n=30), and liberos (n=28). Within each position, players were divided into a more successful group and a less successful group according to team ranking in the latest regional championship and player quality within the team. Height and body mass, somatotype by the Heath-Carter method, and four tests of lower body power, speed, agility and upper body power (i.e., dependent variables) were assessed. Players in different positions differed significantly in height and all three somatotype components, but no significant differences were found in body mass, body mass index or measured physical performance variables. Players of different performance level differed significantly in both anthropometric and physical performance variables. Generally, middle blockers were taller, more ectomorphic, less mesomorphic and endomorphic, whereas liberos were shorter, less ectomorphic, more mesomorphic and endomorphic than players in other positions. More successful players in all positions had a lower body mass index, were less mesomorphic and endomorphic, and more ectomorphic than less successful players. Furthermore, more successful players showed better lower body power, speed, agility and upper body power. The results of this study can potentially provide coaches with useful indications about the use of somatotype selection and physical performance assessment for talent identification and development. PMID:28416892

A prospective cohort study identifying risk factors for shoulder injuries in adolescent elite handball players: the Karolinska Handball Study (KHAST) study protocol.

PubMed

Asker, Martin; Waldén, Markus; Källberg, Henrik; Holm, Lena W; Skillgate, Eva

2017-11-22

Handball is a physical contact sport that includes frequent overhead throwing, and this combination leads to a high rate of shoulder injuries. Several factors have been associated with shoulder injuries in overhead athletes, but strong scientific evidence is lacking for most suggested risk factors. We therefore designed the Karolinska Handball Study (KHAST) with the aim to identify risk factors for shoulder injuries in adolescent male and female elite handball players studying at handball-profiled secondary schools in Sweden. Secondary objectives are to investigate whether shoulder function changes during the competition season and whether the physical profile of the players changes during their time in secondary school. Players aged 15 to 19 years were included during the pre-season period of the 2014-2015 and the 2015-2016 seasons. At inclusion, players signed informed consent and filled in a questionnaire regarding playing position, playing level, previous handball experience, history of shoulder problems and athletic identity. Players also completed a detailed test battery at baseline evaluating the shoulder, neck and trunk. Players were then prospectively monitored weekly during the 2014-2015 and/or 2015-2016 competitive seasons regarding injuries and training/match workload. Results from the annual routine physical tests in the secondary school curriculum including bench press, deep squat, hand grip strength, clean lifts, squat jumps, counter movement jumps, <30 m sprints, chins, dips and Cooper's test will be collected until the end of the competitive season 2017-2018. The primary outcome is the incidence of shoulder injuries and shoulder problems. The secondary outcome is the prevalence of shoulder injuries and shoulder problems. Shoulder problems are frequent among handball players and a reduction of these injuries is therefore warranted. However, in order to introduce appropriate preventive measures, a detailed understanding of the underlying risk factors is needed. Our study has a high potential to identify important risk factors for shoulder injuries in adolescent elite handball players owing to a large study sample, a high response rate, data collection during consecutive seasons, and recording of potential confounding factors.

Can Perceptuo-Motor Skills Assessment Outcomes in Young Table Tennis Players (7–11 years) Predict Future Competition Participation and Performance? An Observational Prospective Study

PubMed Central

2016-01-01

Forecasting future performance in youth table tennis players based on current performance is complex due to, among other things, differences between youth players in growth, development, maturity, context and table tennis experience. Talent development programmes might benefit from an assessment of underlying perceptuo-motor skills for table tennis, which is hypothesized to determine the players’ potential concerning the perceptuo-motor domain. The Dutch perceptuo-motor skills assessment intends to measure the perceptuo-motor potential for table tennis in youth players by assessing the underlying skills crucial for developing technical and tactical qualities. Untrained perceptuo-motor tasks are used as these are suggested to represent a player’s future potential better than specific sport skills themselves as the latter depend on exposure to the sport itself. This study evaluated the value of the perceptuo-motor skills assessment for a talent developmental programme by evaluating its predictive validity for competition participation and performance in 48 young table tennis players (7–11 years). Players were tested on their perceptuo-motor skills once during a regional talent day, and the subsequent competition results were recorded half-yearly over a period of 2.5 years. Logistic regression analysis showed that test scores did not predict future competition participation (p >0.05). Yet, the Generalized Estimating Equations analysis, including the test items ‘aiming at target’, ‘throwing a ball’, and ‘eye-hand coordination’ in the best fitting model, revealed that the outcomes of the perceptuo-motor skills assessment were significant predictors for future competition results (R2 = 51%). Since the test age influences the perceptuo-motor skills assessment’s outcome, another multivariable model was proposed including test age as a covariate (R2 = 53%). This evaluation demonstrates promising prospects for the perceptuo-motor skills assessment to be included in a talent development programme. Future studies are needed to clarify the predictive value in a larger sample of youth competition players over a longer period in time. PMID:26863212

ULTRASONOGRAPHIC ASSESSMENT OF NECK MUSCULAR SIZE AND RANGE OF MOTION IN RUGBY PLAYERS.

PubMed

Hemelryck, Walter; Calistri, Josselin; Papadopoulou, Virginie; Theunissen, Sigrid; Dugardeyn, Christian; Balestra, Costantino

2018-02-01

World Rugby Union laws are constantly evolving towards stringent injury-prevention, particularly for contested scrums, since front row players are most at risk of cervical spine injuries. Recently, some countries have also introduced tailored training programs and minimum performance requirements for playing in the front row. Nevertheless, these approaches lack an objective assessment of each cervical muscle that would provide protective support. Since front row players are the most at risk for cervical spine injuries due to the specific type of contact during scrums, the purpose of this study was to ascertain whether significant differences exist in neck muscle size and range of motion between front row players and players of other positions, across playing categories. Cross-sectional controlled laboratory study. 129 sub-elite male subjects from various first-team squads of Belgian Rugby clubs were recruited. Subjects were grouped according to age: Junior (J) < 19 years old, Senior (S) 19 to 35 years old and Veteran (V) > 35 years old; as well as playing position: Front row players (J = 10, S = 12, V = 11 subjects), (Rest of the) pack (J = 12, S = 12, V = 10), backs (J = 10, S = 11, V = 11). An age-matched control group of non-rugby players was also recruited (J = 10, S = 10, V = 10).For each subject, the total neck circumference (NC) and the cervical range of motion (CROM) were measured. In addition, the thickness of the trapezius (T), splenius capitis (SCa), semispinalis capitis (SCb), semispinalis cervicis (SPC), sternocleidomastoid muscles (SCOM), and the total thickness of all four structures (TT), were measured using ultrasonography. In each age category, compared to controls, rugby players were found to have decreased CROM, an increase in neck circumference (NC), and increased total thickness (TT), trapezius (T), semispinalis capitis (SCb) and sternocleidomastoid muscles (SCOM) sizes. For junior players, the thickness of the semispinalis cervicis (SPC) was also increased compared to controls. The CROM was decreased in front row players compared to pack and back players for all age categories; Front row seniors also showed an increase in trapezius (T), splenius capitis (SCa), semispinalis capitis (SCb) and total thickness (TT), compared to back players. In regard of the differences in cervical values found between player positions, the implementation of both range of motion and echography muscle thickness assessments could serve to create an additional measurement for all front row players, that could complement current pre-participation screening used by rugby federations by objectively monitoring muscular size and motion amplitude around the cervical spine.

The Effect of a Novel Movement Strategy in Decreasing ACL Risk Factors in Female Adolescent Soccer Players: A Randomized Controlled Trial

PubMed Central

Celebrini, Richard G.; Eng, Janice J.; Miller, William C.; Ekegren, Christina L.; Johnston, James D.; Depew, Thomas A.; MacIntyre, Donna L.

2015-01-01

Objective To determine the effect of a novel movement strategy incorporated within a soccer warm-up on biomechanical risk factors for ACL injury during three sport-specific movement tasks. Design Single-blind, randomized controlled clinical trial. Setting Laboratory setting. Participants 20 top-tier female teenage soccer players. Interventions Subjects were randomized to the Core Position and Control movement strategy (Core-PAC) warm-up or standard warm-up which took place prior to their regular soccer practice over a 6-week period. The Core-PAC focuses on getting the centre of mass closer to the plant foot or base of support. Main Outcome Measures Peak knee flexion angle and abduction moments during a side-hop (SH), side-cut (SC) and unanticipated side-cut (USC) task after the 6-weeks with (intervention group only) and without a reminder to use the Core-PAC strategy. Results The Core-PAC group increased peak flexion angles during the SH task (Mean difference = 6.2°, 95% CI: 1.9–10.5°, effect size = 1.01, P = 0.034) after the 6-week warm-up program without a reminder. In addition, the Core-PAC group demonstrated increased knee flexion angles for the side-cut (Mean difference = 8.5°, 95% CI: 4.8–12.2°, ES = 2.02, P = 0.001) and side-hop (Mean difference = 10.0°, 95% CI: 5.7–14.3°, ES = 1.66, P = 0.001) task after a reminder. No changes in abduction moments were found. Conclusions The results of this study suggest that the Core-PAC may be one method of modifying high-risk soccer-specific movements and can be implemented within a practical, team-based soccer warm-up. The results should be interpreted with caution due to the small sample size. PMID:24184850

The effect of laryngoscope handle size on possible endotracheal intubation success in university football, ice hockey, and soccer players.

PubMed

Delaney, J Scott; Al-Kashmiri, Ammar; Baylis, Penny-Jane; Aljufaili, Mahmood; Correa, José A

2012-07-01

To assess the effectiveness of a standard long-handle laryngoscope and a short-handle laryngoscope on ease of possible intubation in football, ice hockey, and soccer players. Prospective crossover study. University Sport Medicine Clinic. Sixty-two university varsity football (62 males), 45 ice hockey (26 males and 19 females), and 39 soccer players (20 males, 19 females). Athletes were assessed for different airway and physical characteristics. Three different physicians then assessed the use of laryngoscopes of different handle sizes in supine athletes who were wearing protective equipment while in-line cervical spine immobilization was maintained. The ease of passage of a laryngoscope blade into the posterior oropharynx of a supine athlete was assessed using both a standard long-handle and a short-handle laryngoscope. Use of a short-handle laryngoscope was easier for all physicians in all sports as compared with a standard-sized laryngoscope. Passage of a laryngoscope blade into the posterior oropharynx of a supine athlete was easiest in soccer players and most difficult in football and ice hockey players for both sizes of laryngoscope. Interference from chest or shoulder pads was a common cause for difficulty in passing the laryngoscope blade into the posterior oropharynx for football and ice hockey players. In the rare instances that an endotracheal intubation is to be attempted on an unconscious athlete, a short-handle laryngoscope may provide the best chance for successful intubation.

An evaluation of wheelchair basketball players' nutritional status and nutritional knowledge levels.

PubMed

Eskici, Günay; Ersoy, Gülgün

2016-03-01

This study aimed to assess the nutritional status of women paralympic athletes and their nutritional knowledge. Twenty two players of National Wheelchair Women Basketball Team (15-38 years) participated in this study and answered a questionnaire (76 questions) Players were at sport camp during the assessment where their body weight is measured regularly by the team coach. The waist, hip size and the height of the players who are able to stand have been used for the assessment, while the knee height of the players who are not able to stand have been measured for the study. SPSS 15.0 and BEBIS (Nutritional Data System) have been used for statistical assessment. The average age and sport years as a player of the participants are; respectively; 25.5±7.2 years and 3.9±2.8 years. The average daily energy consumption is 2867.8±523.6 kcal/day. The average proportion of energy, converted from carbohydrate, protein, fat are been calculated as, respectively; 42.7% (5.3±1.5 g/kg/day), 13.3% (1.6±0.3 g/kg/day), 44% (2.5±0.8 g/kg/day). It is also found that Vitamin B1, folic acid, magnesium, iron and fiber have not been consumed enough. The questions about sport nutrition have been mostly answered incorrectly. Athletes have inadequate food consumption and nutrition information. The athletes have to be educated more about nutrition and they should have nutritional counseling support.

Saccades and memory: baseline associations of the King-Devick and SCAT2 SAC tests in professional ice hockey players.

PubMed

Galetta, Matthew S; Galetta, Kristin M; McCrossin, Jim; Wilson, James A; Moster, Stephen; Galetta, Steven L; Balcer, Laura J; Dorshimer, Gary W; Master, Christina L

2013-05-15

The Sports Concussion Assessment Tool 2 (SCAT2) and King-Devick (K-D) tests have both been proposed as sideline tools to detect sports-related concussion. We performed an exploratory analysis to determine the relation of SCAT2 components, particularly the Standardized Assessment of Concussion (SAC), to K-D test scores in a professional ice hockey team cohort during pre-season baseline testing. We also examined changes in scores for two athletes who developed concussion and had rinkside testing. A modified SCAT2 (no balance testing) and the K-D test, a brief measure of rapid number naming, were administered to 27 members of a professional ice hockey team during the 2011-2012 pre-season. Athletes with concussion also underwent rinkside testing. Lower (worse) scores for the SCAT2 SAC Immediate Memory Score and the overall SAC score were associated with greater (worse) times required to complete the K-D test at baseline. On average, for every 1-point reduction in SAC Immediate Memory Score, we found a corresponding increase (worsening) of K-D time score of 7.3s (95% CI 4.9, 9.7, p<0.001, R(2)=0.62, linear regression, accounting for age). For the overall SAC score, 1-point reductions were associated with K-D score worsening of 2.2s (95% CI 0.6, 3.8, p=0.01, R(2)=0.25, linear regression). In two players tested rinkside immediately following concussion, K-D test scores worsened from baseline by 4.2 and 6.4s. These athletes had no differences found for SCAT2 SAC components, but reported symptoms of concussion. In this study of professional athletes, scores for the K-D test, a measure for which saccadic (fast) eye movements are required for the task of rapid number naming, were associated with reductions in Immediate Memory at a pre-season baseline. Both working memory and saccadic eye movements share closely related anatomical structures, including the dorsolateral prefrontal cortex (DLPFC). A composite of brief rapid sideline tests, including SAC and K-D (and balance testing for non-ice hockey sports), is likely to provide an effective clinical tool to assess the athlete with suspected concussion. Copyright © 2013 Elsevier B.V. All rights reserved.

Acute effects of static and dynamic stretching on jump performance after 15 min of reconditioning shooting phase in basketball players.

PubMed

Annino, Giuseppe; Ruscello, Bruno; Lebone, Pietro; Palazzo, Francesco; Lombardo, Mauro; Padua, Elvira; Verdecchia, Luca; Tancredi, Virginia; Iellamo, Ferdinando

2017-04-01

The aim of this study was to assess the effects of static (SS) and dynamic stretching (DS) on vertical jump performance executed before, immediately after and at the end of the shooting phase (i.e., 15 min later), as to simulate the actual conditions preceding a match, in professional basketball players. Ten elite basketball players (age: 29±6.73 years, height: 194.67±7.75 cm, weight: 91±8.17 kg and BMI 23.8±7.91 kg.m-2) participated to the study. SS and DS protocols were administered during the first training session of the week, 48 hours after the championship match. Stretching protocols consisted in ~7 minutes of general warm-up phase followed by ~8 minutes of SS and DS, performed with a cross-over design., and ~15 minutes of a specific warm-up shooting phase (SP). Vertical jump tests consisted in counter movement jump (CMJ) and CMJ with arm swings (CMJas) and were performed immediately after the end of each stretching phase (preS, postS, postSP). A significant decrease (P=0.05; η2partial=0.29) in jumping tests height occurred in CMJas, when performed after the SS (i.e., PostS). However, no significant differences in jumping performances, occurred after the general warm phase and the specific warm-up shooting phase, between the two stretching protocols. These results would indicate that, overall, stretching routines either dynamic or static, performed before a basketball match are transient and affect only marginally leg muscles performance. Stretching routines, particularly the dynamic ones, may be useful to maintain muscle performance before a competition, provided that this latter begins shortly after.

Gaze Stabilization Test Asymmetry Score as an Indicator of Previous Concussion in a Cohort of Collegiate Football Players.

PubMed

Honaker, Julie A; Criter, Robin E; Patterson, Jessie N; Jones, Sherri M

2015-07-01

Vestibular dysfunction may lead to decreased visual acuity with head movements, which may impede athletic performance and result in injury. The purpose of this study was to test the hypothesis that athletes with history of concussion would have differences in gaze stabilization test (GST) as compared with those without a history of concussion. Cross-sectional, descriptive. University Athletic Medicine Facility. Fifteen collegiate football players with a history of concussion, 25 collegiate football players without a history of concussion. Participants completed the dizziness handicap inventory (DHI), static visual acuity, perception time test, active yaw plane GST, stability evaluation test (SET), and a bedside oculomotor examination. Independent samples t test was used to compare GST, SET, and DHI scores per group, with Bonferroni-adjusted alpha at P < 0.01. Receiver operating characteristic curve analysis and area under the curve (AUC) were used to assess the clinical performance of the GST and SET. Athletes with previous concussion had a larger GST asymmetry score [mean (M) = 12.40, SD = 9.09] than those without concussion (M = 4.92, SD = 4.67; t (18.70) = -2.955, P = 0.008, 95% CI, -12.79 to -2.18, d = -1.37). Clinical performance of the GST (AUC = 0.77) was better than the SET (AUC = 0.61). Results suggest peripheral vestibular or vestibular-visual interaction deficits in collegiate athletes with a history of concussion. The results support further research on the use of GST for sport-related concussion evaluation and monitoring. Inclusion of objective vestibular tests in the concussion protocol may reveal the presence of peripheral vestibular or visual-vestibular deficits. Therefore, the GST may add an important perspective on the effects of concussion.

Visuo-oculomotor skills related to the visual demands of sporting environments.

PubMed

Ceyte, Hadrien; Lion, Alexis; Caudron, Sébastien; Perrin, Philippe; Gauchard, Gérome C

2017-01-01

The aim of this study was to assess the visuo-oculomotor skills of gaze orientation in selected sport activities relative to visual demands of the sporting environment. Both temporal and spatial demands of the sporting environment were investigated: The latency and accuracy of horizontal saccades and the gain of the horizontal smooth pursuit of the sporting environment were investigated in 16 fencers, 19 tennis players, 12 gymnasts, 9 swimmers and 18 sedentary participants. For the saccade test, two sequences were tested: In the fixed sequence, participants knew in advance the time interval between each target, as well as the direction and the amplitude of its reappearance; in the Freyss sequence however, the spatial changes of the target (direction and amplitude) were known in advance by participants but the time interval between each target was unknown. For the smooth-pursuit test, participants were instructed to smoothly track a target moving in a predictable sinusoidal, horizontal way without corrective ocular saccades, nor via anticipation or head movements. The results showed no significant differences between specificities of selected sporting activities via the saccade latency (although shorter than in non-athletes), contrary to saccade accuracy and the gain of smooth pursuit. Higher saccade accuracy was observed overall in fencers compared to non-athletes and all other sportsmen with the exception of tennis players. In the smooth-pursuit task, only tennis players presented a significantly higher gain compared to non-athletes and gymnasts. These sport-specific characteristics of the visuo-oculomotor skills are discussed with regard to the different cognitive skills such as attentional allocation and cue utilization ability as well as with regard to the difference in motor preparation.

Preparation time influences ankle and knee joint control during dynamic change of direction movements.

PubMed

Fuerst, Patrick; Gollhofer, Albert; Gehring, Dominic

2017-04-01

The influence of preparation time on ankle joint biomechanics during highly dynamic movements is largely unknown. The aim of this study was to evaluate the impact of limited preparation time on ankle joint loading during highly dynamic run-and-cut movements. Thirteen male basketball players performed 45°-sidestep-cutting and 180°-turning manoeuvres in reaction to light signals which appeared during the approach run. Both movements were executed under (1) an easy condition, in which the light signal appeared very early, (2) a medium condition and (3) a hard condition with very little time to prepare the movements. Maximum ankle inversion angles, moments and velocities during ground contact, as well as EMG signals of three lower extremity muscles, were analysed. In 180°-turning movements, reduced preparation time led to significantly increased maximum ankle inversion velocities. Muscular activation levels, however, did not change. Increased inversion velocities, without accompanying changes in muscular activation, may have the potential to destabilise the ankle joint when less preparation time is available. This may result in a higher injury risk during turning movements and should therefore be considered in ankle injury research and the aetiology of ankle sprains.

Ad libitum fluid intake does not prevent dehydration in suboptimally hydrated young soccer players during a training session of a summer camp.

PubMed

Arnaoutis, Giannis; Kavouras, Stavros A; Kotsis, Yiannis P; Tsekouras, Yiannis E; Makrillos, Michalis; Bardis, Costas N

2013-06-01

There is a lack of studies concerning hydration status of young athletes exercising in the heat. To assess preexercise hydration status in young soccer players during a summer sports camp and to evaluate body- water balance after soccer training sessions. Initial hydration status was assessed in 107 young male soccer players (age 11-16 yr) during the 2nd day of the camp. Seventy-two athletes agreed to be monitored during 2 more training sessions (3rd and 5th days of the camp) to calculate dehydration via changes in body weight, while water drinking was allowed ad libitum. Hydration status was assessed via urine specific gravity (USG), urine color, and changes in total body weight. Mean environmental temperature and humidity were 27.2 ± 2 °C and 57% ± 9%, respectively. According to USG values, 95 of 107 of the players were hypohydrated (USG ≥ 1.020) before practice. The prevalence of dehydration observed was maintained on both days, with 95.8% and 97.2% of the players being dehydrated after the training sessions on the 3rd and 5th days, respectively. Despite fluid availability, 54 of the 66 (81.8%) dehydrated players reduced their body weight (-0.35 ± 0.04 kg) as a response to training, while 74.6% (47 out of the 63) further reduced their body weight (-0.22 ± 0.03 kg) after training on the 5th day. Approximately 90% of the young soccer players who began exercising under warm weather conditions were hypohydrated, while drinking ad libitum during practice did not prevent further dehydration in already dehydrated players.

Players Off the Field. How Jim Delany and Roy Kramer Took over Big-Time College Sports.

ERIC Educational Resources Information Center

Suggs, Welch

2000-01-01

Traces the history of the college football bowl system and describes the movement toward replacing the bowl game system with a national championship playoff system. Focuses on the roles of J. Delany, commission of the Big Ten Conference and R. Kramer, commissioner of the Southeastern Conference, in perpetuating the current college football bowl…

Top-Level Players' Visual Control of Interceptive Actions: Bootsma and Van Wieringen (1990) 20 Years Later

ERIC Educational Resources Information Center

Bootsma, Reinoud J.; Fernandez, Laure; Morice, Antoine H. P.; Montagne, Gilles

2010-01-01

Using a two-step approach, Van Soest et al. (2010) recently questioned the pertinence of the conclusions drawn by Bootsma and Van Wieringen (1990) with respect to the visual regulation of an exemplary rapid interceptive action: the attacking forehand drive in table tennis. In the first step, they experimentally compared the movement behaviors of…

U.S. Indian Policy, 1865-1890: As Illuminated through the Lives of Charles A. Eastman and Elaine Goodale Eastman

ERIC Educational Resources Information Center

Eick, Gretchen Cassel

2008-01-01

This article lays out U.S. Indian policy in the Great Plains during the twenty-five years after the Civil War by examining chronologically specific "players" that shaped and reshaped that policy: the U.S. Army, the President and Interior Department, Congress, religious organizations, whites in the Indian reform movement, settlers surging…

Expertise and the spatio-temporal characteristics of anticipatory information pick-up from complex movement patterns.

PubMed

Müller, Sean; Abernethy, Bruce; Eid, Michael; McBean, Rohan; Rose, Matthew

2010-01-01

Groups of high- (n = 14), intermediate- (n = 12), and low-skilled (n = 15) cricket batsmen participated in two experiments to examine expertise-related differences in anticipatory information pick-up that combined temporal and spatial occlusion methodologies. In experiment 1 participants were shown video displays of a bowler delivering one of three different types of delivery with the display manipulated so that only selected local features of the bowler's movement pattern (bowling hand, bowling hand and arm, trunk, lower body, or whole body) were visible and then only for specific time periods prior to ball release. Only the highly-skilled players were able to produce better-than-chance predictions of ball type and then only under a limited set of display conditions. Information from bowling hand and arm cues was particularly critical although continuous visibility of these cues was apparently not essential for information pick-up. In experiment 2 the order in which particular features were made visible throughout the bowler's movement pattern was varied in an attempt to find the sequence of cues that was most favourable for effective information pick-up. The necessity in this experiment to switch vision between different features eliminated the highly-skilled players' capability to anticipate. Expert anticipation is dependent on sensitivity to information arising from a select set of local cues, and forced attentional switches between different cues negate effective information pick-up and, with it, the expert advantage.

The relationship between movement speed and duration during soccer matches.

PubMed

Roecker, Kai; Mahler, Hubert; Heyde, Christian; Röll, Mareike; Gollhofer, Albert

2017-01-01

The relationship between the time duration of movement (t(dur)) and related maximum possible power output has been studied and modeled under many conditions. Inspired by the so-called power profiles known for discontinuous endurance sports like cycling, and the critical power concept of Monod and Scherrer, the aim of this study was to evaluate the numerical characteristics of the function between maximum horizontal movement velocity (HSpeed) and t(dur) in soccer. To evaluate this relationship, GPS data from 38 healthy soccer players and 82 game participations (≥30 min active playtime) were used to select maximum HSpeed for 21 distinct t(dur) values (between 0.3 s and 2,700 s) based on moving medians with an incremental t(dur) window-size. As a result, the relationship between HSpeed and Log(t(dur)) appeared reproducibly as a sigmoidal decay function, and could be fitted to a five-parameter equation with upper and lower asymptotes, and an inflection point, power and decrease rate. Thus, the first three parameters described individual characteristics if evaluated using mixed-model analysis. This study shows for the first time the general numerical relationship between t(dur) and HSpeed in soccer games. In contrast to former descriptions that have evaluated speed against power, HSpeed against t(dur) always yields a sigmoidal shape with a new upper asymptote. The evaluated curve fit potentially describes the maximum moving speed of individual players during the game, and allows for concise interpretations of the functional state of team sports athletes.

The relationship between movement speed and duration during soccer matches

PubMed Central

Mahler, Hubert; Heyde, Christian; Röll, Mareike; Gollhofer, Albert

2017-01-01

The relationship between the time duration of movement (t(dur)) and related maximum possible power output has been studied and modeled under many conditions. Inspired by the so-called power profiles known for discontinuous endurance sports like cycling, and the critical power concept of Monod and Scherrer, the aim of this study was to evaluate the numerical characteristics of the function between maximum horizontal movement velocity (HSpeed) and t(dur) in soccer. To evaluate this relationship, GPS data from 38 healthy soccer players and 82 game participations (≥30 min active playtime) were used to select maximum HSpeed for 21 distinct t(dur) values (between 0.3 s and 2,700 s) based on moving medians with an incremental t(dur) window-size. As a result, the relationship between HSpeed and Log(t(dur)) appeared reproducibly as a sigmoidal decay function, and could be fitted to a five-parameter equation with upper and lower asymptotes, and an inflection point, power and decrease rate. Thus, the first three parameters described individual characteristics if evaluated using mixed-model analysis. This study shows for the first time the general numerical relationship between t(dur) and HSpeed in soccer games. In contrast to former descriptions that have evaluated speed against power, HSpeed against t(dur) always yields a sigmoidal shape with a new upper asymptote. The evaluated curve fit potentially describes the maximum moving speed of individual players during the game, and allows for concise interpretations of the functional state of team sports athletes. PMID:28742832

Effect of a gluteal activation warm-up on explosive exercise performance.

PubMed

Parr, Matt; Price, Phil Db; Cleather, Daniel J

2017-01-01

To evaluate the effect of a gluteal activation warm-up on the performance of an explosive exercise (the high hang pull (HHP)). Seventeen professional rugby union players performed one set of three HHPs (with 80% of their one repetition maximum load) following both a control and activation warm-up. Peak electrical activity of the gluteus maximus and medius was quantified using electromyography (EMG). In addition, the kinematics and kinetics of nine players was also recorded using force plate and motion capture technology. These data were analysed using a previously described musculoskeletal model of the right lower limb in order to provide estimates of the muscular force expressed during the movement. The mean peak EMG activity of the gluteus maximus was significantly lower following the activation warm-up as compared with the control (p<0.05, effect size d=0.30). There were no significant differences in the mean peak estimated forces in gluteus maximus and medius, the quadriceps or hamstrings (p=0.053), although there was a trend towards increased force in gluteus maximus and hamstrings following the activation warm-up. There were no differences between the ground reaction forces following the two warm-ups. This study suggests that a gluteal activation warm-up may facilitate recruitment of the gluteal musculature by potentiating the glutes in such a way that a smaller neural drive evokes the same or greater force production during movement. This could in turn potentially improve movement quality.

An evaluation of end-point trajectory planning during skilled kicking.

PubMed

Ford, Paul; Hodges, Nicola J; Mark Williams, A

2009-01-01

There is evidence that actions are planned by anticipation of their external effects, with the strength of this effect being dependent on the amount of prior practice. In Experiment 1, skilled soccer players performed a kicking task under four conditions: planning in terms of an external action effect (i.e., ball trajectory) or in terms of body movements, either with or without visual error feedback. When feedback was withheld, a ball focus resulted in more accurate outcomes than a body focus. When visual feedback was allowed, there was no difference between these two conditions. In Experiment 2, both skilled and novice soccer players were tested with the addition of a control condition and in the absence of visual feedback. For both groups there was evidence that a ball focus was more beneficial for performance than a body focus, particularly in terms of movement kinematics where correlations across the joints were generally higher for body rather than ball planning. Most skilled participants reported that ball planning felt more normal than body planning. These experiments provide some evidence that actions are planned in terms of their external action effects, supporting the common-coding hypothesis of action planning.

Effects of short-term two weeks low intensity plyometrics combined with dynamic stretching training in improving vertical jump height and agility on trained basketball players.

PubMed

Ramachandran, Selvam; Pradhan, Binita

2014-01-01

Sport specific training in basketball players should focus on vertical jump height and agility in consistent with demands of the sport. Since plyometrics training improves vertical jump height and agility, it can be useful training strategy to improve the performance of basketball players. A convenience sample of thirty professional basketball players were recruited. Following pre-intervention assessment, interventions using plyometrics training and dynamic stretching protocol was administered on the basketball players. The outcome measures were assessed before the intervention and at the end of first and second week. Statistically significant improvements in vertical jump height (31.68 ± 11.64 to 37.57 ± 16.74; P < 0.012) and agility (16.75 ± 2.49 to 16.51 ± 2.80; P <0.00) were observed between pretest--posttest measures and no changes in muscle girth and isometric muscle strength. The study concludes that short term two weeks plyometrics training combined with dynamic stretching as a useful sport specific training strategy to improve vertical jump height and agility on trained basketball players.

Examining Player Anger in World of Warcraft

NASA Astrophysics Data System (ADS)

Barnett, Jane; Coulson, Mark; Foreman, Nigel

This questionnaire study of the sources of anger in World of Warcraft applies classical quantitative measurement scale construction to a new problem, generating a host of questionnaire items that could find use in future studies, and identifying four major categories of events that cause negative effect among players. First, 33 players provided examples of in-game scenarios that had made them angry, and their responses were culled to create a 93-item battery rated by hundreds of player respondents in terms of anger intensity and anger frequency. An iterative process of factor analysis and scale reliability assessment led to a 28-item instrument measuring four anger-provoking factors: Raids/Instances, Griefers, Perceived Time Wasting, and Anti-social Players. These anger-causing scenarios were then illustrated by concrete examples from player and researcher experiences in World of Warcraft. One striking finding is that players become angry at other players' negative behavior, regardless of whether that behavior was intended to harm.

Glial activation in the collagenase model of nociception associated with osteoarthritis.

PubMed

Adães, Sara; Almeida, Lígia; Potes, Catarina S; Ferreira, Ana Rita; Castro-Lopes, José M; Ferreira-Gomes, Joana; Neto, Fani L

2017-01-01

Background Experimental osteoarthritis entails neuropathic-like changes in dorsal root ganglia (DRG) neurons. Since glial activation has emerged as a key player in nociception, being reported in numerous models of neuropathic pain, we aimed at evaluating if glial cell activation may also occur in the DRG and spinal cord of rats with osteoarthritis induced by intra-articular injection of collagenase. Methods Osteoarthritis was induced by two injections, separated by three days, of 500 U of type II collagenase into the knee joint of rats. Movement-induced nociception was evaluated by the Knee-Bend and CatWalk tests during the following six weeks. Glial fibrillary acidic protein (GFAP) expression in satellite glial cells of the DRG was assessed by immunofluorescence and Western Blot analysis; the pattern of GFAP and activating transcription factor-3 (ATF-3) expression was also compared through double immunofluorescence analysis. GFAP expression in astrocytes and IBA-1 expression in microglia of the L3-L5 spinal cord segments was assessed by immunohistochemistry and Western Blot analysis. The effect of the intrathecal administration of fluorocitrate, an inhibitor of glial activation, on movement-induced nociception was evaluated six weeks after the first collagenase injection. Results GFAP expression in satellite glial cells of collagenase-injected animals was significantly increased six weeks after osteoarthritis induction. Double immunofluorescence showed GFAP upregulation in satellite glial cells surrounding ATF-3-positive neurons. In the spinal cord of collagenase-injected animals, an ipsilateral upregulation of GFAP and IBA-1 was also observed. The inhibition of glial activation with fluorocitrate decreased movement- and loading-induced nociception. Conclusion Collagenase-induced knee osteoarthritis leads to the development of nociception associated with movement of the affected joint and to the activation of glial cells in both the DRG and the spinal cord. Inhibition of glial cell activation by fluorocitrate decreases these osteoarthritis-associated nociceptive behaviours. These results suggest that glial cell activation may play a role in the development of chronic pain in this experimental model of osteoarthritis.

Throwing velocity and kinematics in elite male water polo players.

PubMed

Melchiorri, G; Padua, E; Padulo, J; D'Ottavio, S; Campagna, S; Bonifazi, M

2011-12-01

Fifty-three members of the Italian Men Water Polo Team were filmed using two synchronized cameras, while they were shooting a goal. Considering the differences in body mass, height, training strategies and the technical-tactical features of the players, the aims of this study were to employ video-analysis techniques in order to investigate selected kinematic parameters in water polo throwing, and to provide comprehensive quantitative information on the throwing movement in relation to the different team player positions. Video analysis was used to estimate the elbow angle at release, the shoulder angle at follow through, the back and head height at ball release, trunk rotation angle and ball velocity at release. Ball release velocities ranged from 21.0 to 29.8 m/s (average value 25.3±1.4 m/s), for field players. Goal keepers show the lowest team values (average 21.7±0.3 m/s). Similar to previous study results, ball release was typically reached just prior to the elbow approaching full extension (151.6±3.6°), and the follow through shoulder angle was 143±5.9°. No significant statistical difference was recorded between injured and non-injured athletes. No positive association was demonstrated between physical characteristics (body mass and height) and ball velocity.

Changes in practice task constraints shape decision-making behaviours of team games players.

PubMed

Correia, Vanda; Araújo, Duarte; Duarte, Ricardo; Travassos, Bruno; Passos, Pedro; Davids, Keith

2012-05-01

This study examined the effects of manipulating relative positioning between defenders (initial distance apart) on emergent decision-making and actions in a 1 vs. 2 rugby union performance sub-phase. Twelve experienced youth players performed 80 trials of a 1 (attacker) vs. 2 (defenders) practice task in which the starting distance between defenders was systematically decreased. Movement displacement trajectories of participants were video recorded to obtain 2D positional data. The independent variable was the starting distance between defenders and dependent variables were: (i) performance outcome (try or tackle), (ii) mean speed of all players during performance, and (iii), time between the first crossover and the end of the trial. Repeated measures ANOVA was used to compare the effects of different starting distances on performance. Shorter starting distances between defenders were associated with a higher frequency of effective tackle outcomes, lower mean speeds of all participants, and a greater time period between the first crossover and the end of the trial. Decision-making behaviours emerged as a function of changes in participants' spatial location during performance. This observation supports the importance of manipulating key spatial-temporal variables in designing representative practice task constraints that induce functional player-environment interactions in team sports training. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of plyometric training on soccer players

PubMed Central

Wang, Ying-Chun; Zhang, Na

2016-01-01

Plyometric training (PT) is a technique used to increase strength and explosiveness. It consists of physical exercises in which muscles exert maximum force at short intervals to increase dynamic performances. In such a training, muscles undergo a rapid elongation followed by an immediate shortening (stretch-shortening contraction), utilizing the elastic energy stored during the stretching phase. There is consensus on the fact that when used, PT contributes to improvement in vertical jump performance, acceleration, leg strength, muscular power, increase of joint awareness and overall sport-specific skills. Consequently, PT which was primarily used by martial artists, sprinters and high jumpers to improve performances has gained in popularity and has been used by athletes in all types of sports. However, although PT has been shown to increase performance variables in many sports, little scientific information is currently available to determine whether PT actually enhances skill performance in soccer players, considering that soccer is an extremely demanding sport. Soccer players require dynamic muscular performance for fighting at all levels of training status, including rapid movements such as acceleration and deceleration of the body, change of direction, vertical and horizontal jumps, endurance, speed as well as power for kicking and tackling. In this review we discussed the effects of PT on soccer players by considering gender and age categories. PMID:27446242

Aerobic conditioning for team sport athletes.

PubMed

Stone, Nicholas M; Kilding, Andrew E

2009-01-01

Team sport athletes require a high level of aerobic fitness in order to generate and maintain power output during repeated high-intensity efforts and to recover. Research to date suggests that these components can be increased by regularly performing aerobic conditioning. Traditional aerobic conditioning, with minimal changes of direction and no skill component, has been demonstrated to effectively increase aerobic function within a 4- to 10-week period in team sport players. More importantly, traditional aerobic conditioning methods have been shown to increase team sport performance substantially. Many team sports require the upkeep of both aerobic fitness and sport-specific skills during a lengthy competitive season. Classic team sport trainings have been shown to evoke marginal increases/decreases in aerobic fitness. In recent years, aerobic conditioning methods have been designed to allow adequate intensities to be achieved to induce improvements in aerobic fitness whilst incorporating movement-specific and skill-specific tasks, e.g. small-sided games and dribbling circuits. Such 'sport-specific' conditioning methods have been demonstrated to promote increases in aerobic fitness, though careful consideration of player skill levels, current fitness, player numbers, field dimensions, game rules and availability of player encouragement is required. Whilst different conditioning methods appear equivalent in their ability to improve fitness, whether sport-specific conditioning is superior to other methods at improving actual game performance statistics requires further research.

Cognitive distortions, anxiety, and depression among regular and pathological gambling online poker players.

PubMed

Barrault, Servane; Varescon, Isabelle

2013-03-01

The aims were to assess cognitive distortions and psychological distress (anxiety and depression) among online poker players of different levels of gambling intensity (non-pathological gamblers [NPG], problem gamblers [PbG], and pathological gamblers [PG]), and to examine the relationship between these variables and gambling pathology. Overall, 245 regular online poker players recruited on an Internet forum completed online self-report scales assessing pathological gambling (South Oaks Gambling Screen [SOGS]), psychological distress (Hospital Anxiety and Depression Scale [HADS]) and cognitive distortions (Gambling-Related Cognition Scale). Based on their SOGS scores, poker players were ranked into three groups: NPG (n=146), PbG (n=55), and PG (n=44). All poker players appeared to be more anxious than depressive. PG exhibited higher levels of depression and anxiety than did PbG and NPG. Cognitive distortions also significantly discriminated PG from PbG and NPG. A regression model showed that the perceived inability to stop gambling, the illusion of control, depression (HADS D), and anxiety were good predictors for pathological gambling among poker players. Our results suggest that cognitive distortions play an important role in the development and maintenance of gambling pathology. This study also underlines the role of anxiety and depression in pathological gambling among poker players. It seems relevant to take these elements into account in the research, prevention, and treatment of pathological gambling poker players.

Pelvic Rotation and Lower Extremity Motion with Two Different Front Foot Directions in the Tennis Backhand Groundstroke

PubMed Central

Iwamoto, Sayumi; Fukubayashi, Toru; Hume, Patria

2013-01-01

When a tennis player steps forward to hit a backhand groundstroke in closed stance, modifying the direction of the front foot relative to the net may reduce the risk of ankle injury and increase performance. This study evaluated the relationship between pelvic rotation and lower extremity movement during the backhand groundstroke when players stepped with toes parallel to the net (Level) or with toes pointed towards the net (Net). High school competitive tennis players (eleven males and seven females, 16.8 ± 0.8 years, all right- handed) performed tennis court tests comprising five maximum speed directional runs to the court intersection line to hit an imaginary ball with forehand or backhand swings. The final backhand groundstroke for each player at the backcourt baseline was analyzed. Pelvic rotation and lower extremity motion were quantified using 3D video analysis from frontal and sagittal plane camera views reconstructed to 3D using DLT methods. Plantar flexion of ankle and supination of the front foot were displayed for both Net and Level groups during the late phase of the front foot step. The timings of the peak pelvis rotational velocity and peak pelvis rotational acceleration showed different pattern for Net and Level groups. The peak timing of the pelvis rotational velocity of the Level group occurred during the late phase of the step, suggesting an increase in the risk of inversion ankle sprain and a decrease in stroke power compared to the Net group. Key Points Regarding the movement of the forefoot, the Net group and the Level group showed a pattern of supination-pronation-supination during the front stepping foot contact phase (FSFCP). However, the Level group showed only supination of various degrees during FSFCP. For the Net group, the maximum angular velocity of pelvis occurred in the early phase of FSFCP before impact; however, for the Level group, the maximum angular velocity of pelvis occurred in the latter phase of FSFCP after impact. The Level group players showed a potentially higher risk of inversion ankle sprain during the latter stage of FSFCP as pelvic rotation reached maximum angular velocity. The Net group may have a more effective kinetic chain during backhand groundstrokes, which ultimately enhances performance. PMID:24149814

Free-Weight Augmentation With Elastic Bands Improves Bench Press Kinematics in Professional Rugby Players.

PubMed

García-López, David; Hernández-Sánchez, Sonsoles; Martín, Esperanza; Marín, Pedro J; Zarzosa, Fernando; Herrero, Azael J

2016-09-01

García-López, D, Hernández-Sánchez, S, Martín, E, Marín, PJ, Zarzosa, F, and Herrero, AJ. Free-weight augmentation with elastic bands improves bench press kinematics in professional rugby players. J Strength Cond Res 30(9): 2493-2499, 2016-This study aimed to investigate the effects of combining elastic bands to free weight resistance (EB + FWR) on the acceleration-deceleration and velocity profiles of the bench press in professional rugby players and recreationally trained subjects. Sixteen male subjects (8 rugby players and 8 recreationally trained subjects) were randomly assigned to complete 2 experimental conditions in a crossover fashion: EB + FWR and FWR. In both conditions, subjects performed 1 bench press set to volitional exhaustion with a load equivalent to the 85% of 1 repetition maximum (1RM). In the EB + FWR condition, the contribution of elastic resistance was approximately 20% of the selected load (85% 1RM). Results indicate that EB + FWR condition increased significantly the range of concentric movement in which the barbell is accelerated. This increase was significantly higher in rugby players (35%) in comparison with recreationally trained subjects (13%). Maximal velocity was also increased in EB + FWR (17%), when compared with FWR condition. These results suggest that when combined with variable resistance (i.e., EB), the external resistance seems to be more evenly distributed over the full range of motion, decreasing the need for dramatic deceleration at the end of the concentric phase. The present data also indicate that the kinematic benefits of an EB + FWR approach seems to be more prominent in athletes from modalities in which high level of strength and power are required (i.e., rugby players).

[Suffering pain in segment lumbar spine and occurrence of weak links of biokinematics chain in kayakers and rowers].

PubMed

Wójcik, Małgorzata; Siatkowski, Idzi

2011-01-01

Spine pain is a serious clinical problem of physically active people and sportplayers . The pain may have different nature, related to different segments of the spine. Its intensity and frequency may impair the functionality of man. Most back pain is connected with the lumbo-sacral and cervical part of a spine. MAIN AIM: The hypothesis was: 1) That there were not any weak links of biokinematics chain. 2) Pain feeling in young players in the lumbar spine (LBP). The aim of this study was to determine in which direction and location the most weak links would occur in biokinematics chain and whether it was correlated with gender. In addition, it was examined whether a correlation between the weak links' presence in the lumbar spine and the occurrence of LBP existed and if it was connected with gender of the player. This study involved 40 players from Walcz School Sports Championships, including the twenty kayakers (8 women and 12 men), 13 canoeists and 7 rowers. The average age of players was 16.00 +/- 0.99, mean of training years was 4.92 +/- 2.20. Low threshold Performance Matrix tests were used for assessing the presence of weak links. Through analysis and identification of performed movement the weakest links in the biokinetics chain were found. Numeric scale was used for the evaluation of lumbar pain (LBP). The results were statistically analyzed. The main characteristics of statistical and graphical presentations were performed for the received values of weak links. The hypothesis of variances equality was verified, and all the hypotheses mentioned above were also verified using ANOVA analysis of variations and Tukey test for low threshold of weak links. 1) The presence of weak links of biokinematics chain was found in all players especially in the lumbar spine, the presence is not associated with gender. Most weak links in the lumbar part occurred in the direction of rotation. 2) There is a correlation of the weak links of the lumbar spine and LBP, but it is not connected with gender. 3) The relationship between pain suffering in the lumbar spine (LBP) and the number of weak links of biokinematics chain was defined.

Training Effects of the FIFA 11+ Kids on Physical Performance in Youth Football Players: A Randomized Control Trial.

PubMed

Pomares-Noguera, Carlos; Ayala, Francisco; Robles-Palazón, Francisco Javier; Alomoto-Burneo, Juan F; López-Valenciano, Alejandro; Elvira, José L L; Hernández-Sánchez, Sergio; De Ste Croix, Mark

2018-01-01

To analyze the training effects of the FIFA 11+ kids on several parameters of physical performance in male youth football players. Twenty-three youth players were randomized within each team into two groups (control vs. intervention). The intervention group performed the FIFA 11+ kids programme 2 times a week for 4 weeks; the control groups completed their normal warm-up routines. Thirteen physical performance measures {range of motion (hip, knee, and ankle joints), dynamic postural control (measured throughout the Y balance test), 20 m sprint time, slalom dribble with a ball, agility, vertical jumping height [counter movement jump (CMJ) and drop jump (DJ)], horizontal jump distance, accuracy when volleying a ball [measured throughout the Wall Volley test]} were assessed. All physical performance parameters were compared via magnitude-based inference analysis. Significant between-group differences in favor of the FIFA 11+ players were found for dynamic postural control {anterior [mean and 90% confidence intervals (CI) = 1 cm, from -1.6 to 3.5 cm] and posteromedial (mean and 90% CI = 5.1 cm, from -1.8 to 12 cm) and posterolateral (mean and 90% CI = 4.8 cm, from 0.6 to 9.0 cm) distances}, agility run (mean and 90% CI = 0.5 s, from -0.9 to 0 s), vertical jump height [CMJ (mean and 90% CI = 3.1 cm, from 0.2 to 6.1 cm) and DJ (mean and 90% CI = 1.7 cm, from -0.5 to 3.9 cm)], and horizontal jump distance (mean and 90% CI = 2.5 cm, from -8 to 15 cm). The control groups showed better performance in 20 m sprint time (mean and 90% CI = -0.05 s, from -0.11 to 0.07) and wall volley tests (mean and 90% CI = 0.2, from -0.2 to 0.6) compared to the intervention group. The main findings of this study suggest that just 4 weeks of implementation of the FIFA 11+ kids produces improved physical performance compared with traditional warm-up routines in youth soccer players.

Perceptions of wellness to monitor adaptive responses to training and competition in elite Australian football.

PubMed

Gastin, Paul B; Meyer, Denny; Robinson, Dean

2013-09-01

Perceptions of wellness are often used by athletes and coaches to assess adaptive responses to training. The purpose of this research was to describe how players were coping with the demands of elite level Australian football over a competitive season using subjective ratings of physical and psychological wellness and to assess the ecological validity of such a monitoring approach. Twenty-seven players completed ratings for 9 items (fatigue, general muscle, hamstring, quadriceps, pain/stiffness, power, sleep quality, stress, well-being). Players subjectively rated each item as they arrived at the training or competition venue on a 1-5 visual analog scale, with 1 representing the positive end of the continuum. A total of 2,583 questionnaires were analyzed from completions on 183 days throughout the season (92 ± 24 per player, 103 ± 20 per week; mean ± SD). Descriptive statistics and multilevel modelling were used to understand how player ratings of wellness varied over the season and during the week leading into game day and whether selected player characteristics moderated these relationships. Results indicated that subjective ratings of physical and psychological wellness were sensitive to weekly training manipulations (i.e., improve steadily throughout the week to a game day low, p < 0.001), to periods of unloading during the season (i.e., a week of no competition, p < 0.05) and to individual player characteristics (e.g., muscle strain after a game was poorer in players with high maximum speed, p < 0.01). It is concluded that self-reported player ratings of wellness provide a useful tool for coaches and practitioners to monitor player responses to the rigorous demands of training, competition, and life as a professional athlete.

Roles of Social Movement Organizations for Securing Workers' Safety in Korea: A Case Study of Abolition of the 30-Minute Delivery Guarantee Program in Pizza Delivery Service.

PubMed

Park, Ji-Eun; Kim, Myoung-Hee

2016-07-01

Many restaurants in Korea maintain quick-delivery service programs to satisfy customers. This service allows delivery workers limited time to deliver, which frequently put them in danger. Most of the workers are young, work part-time, and are rarely organized into trade unions. In this article, through a case study of the social movement to abolish the 30-minute delivery guarantee program of pizza companies in Korea, we argue that social movements involving social movement organizations (SMOs) and individual citizens could serve as a means to rectify this problem. We show how the SMOs developed and expanded the movement using a framing perspective and how the general public became involved through social media. Data was collected via online searching. Interview scripts from key players of SMOs and unofficial documents they provided were also reviewed. Three SMOs primarily led the movement, successfully forming a frame that emphasized social responsibility. SMOs also utilized social media to link their standing frame with unmobilized citizens and to expand the movement. We identified contributing factors and limitations of the movement and drew lessons that could be applied to other sectors where workers are in vulnerable positions. © The Author(s) 2016.

Assessing video games to improve driving skills: a literature review and observational study.

PubMed

Sue, Damian; Ray, Pradeep; Talaei-Khoei, Amir; Jonnagaddala, Jitendra; Vichitvanichphong, Suchada

2014-08-07

For individuals, especially older adults, playing video games is a promising tool for improving their driving skills. The ease of use, wide availability, and interactivity of gaming consoles make them an attractive simulation tool. The objective of this study was to look at the feasibility and effects of installing video game consoles in the homes of individuals looking to improve their driving skills. A systematic literature review was conducted to assess the effect of playing video games on improving driving skills. An observatory study was performed to evaluate the feasibility of using an Xbox 360 Kinect console for improving driving skills. Twenty-nine articles, which discuss the implementation of video games in improving driving skills were found in literature. On our study, it was found the Xbox 360 with Kinect is capable of improving physical and mental activities. Xbox Video games were introduced to engage players in physical, visual and cognitive activities including endurance, postural sway, reaction time, eyesight, eye movement, attention and concentration, difficulties with orientation, and semantic fluency. However, manual dexterity, visuo-spatial perception and binocular vision could not be addressed by these games. It was observed that Xbox Kinect (by incorporating Kinect sensor facilities) combines physical, visual and cognitive engagement of players. These results were consistent with those from the literature review. From the research that has been carried out, we can conclude that video game consoles are a viable solution for improving user's physical and mental state. In future we propose to carry a thorough evaluation of the effects of video games on driving skills in elderly people.

Influence of Number of Contact Efforts on Running Performance During Game-Based Activities.

PubMed

Johnston, Rich D; Gabbett, Tim J; Jenkins, David G

2015-09-01

To determine the influence the number of contact efforts during a single bout has on running intensity during game-based activities and assess relationships between physical qualities and distances covered in each game. Eighteen semiprofessional rugby league players (age 23.6 ± 2.8 y) competed in 3 off-side small-sided games (2 × 10-min halves) with a contact bout performed every 2 min. The rules of each game were identical except for the number of contact efforts performed in each bout. Players performed 1, 2, or 3 × 5-s wrestles in the single-, double-, and triple-contact game, respectively. The movement demands (including distance covered and intensity of exercise) in each game were monitored using global positioning system units. Bench-press and back-squat 1-repetition maximum and the 30-15 Intermittent Fitness Test (30-15IFT) assessed muscle strength and high-intensity-running ability, respectively. There was little change in distance covered during the single-contact game (ES = -0.16 to -0.61), whereas there were larger reductions in the double- (ES = -0.52 to -0.81) and triple-contact (ES = -0.50 to -1.15) games. Significant relationships (P < .05) were observed between 30-15IFT and high-speed running during the single- (r = .72) and double- (r = .75), but not triple-contact (r = .20) game. There is little change in running intensity when only single contacts are performed each bout; however, when multiple contacts are performed, greater reductions in running intensity result. In addition, high-intensity-running ability is only associated with running performance when contact demands are low.

The colour of a football outfit affects visibility and team success.

PubMed

Olde Rikkert, Joris; Haes, Vincent De; Barsingerhorn, Annemiek D; Theelen, Thomas; Olde Rikkert, Marcel G M

2015-01-01

We investigated the impact of the colour of football outfits on localising football players and on the results of football matches. Two studies were conducted: an experimental study examining the effects of outfit colour on the assessment of the positions of computer-animated football players in a video set-up (study 1) and a retrospective study on professional football clubs' performances dependent on their outfit colours (study 2). The studies were conducted with 18 human volunteers aged 15-18 years (study 1) and league results from 10 professional European football teams over 17 years (1995-2013) (study 2). We analysed the number of correct assessments of the positions of virtual football players with different outfit colours (study 1) and analysed the relationship between match results and outfits' colours (study 2). Study 1 showed that the position of players wearing white outfits was better assessed in 5.2% of the trials compared to players wearing green outfits (P = 0.007). Study 2 showed that Manchester City conceded less goals against in away games in highly visible kits (r = 0.62; P = 0.024), while Newcastle United conceded less goals and won more points while playing in kits associated with low visibility (r = 0.63; P = 0.007; r = 0.50; P = 0.040, respectively). We conclude that the colour of football outfits affects evaluations of football players' positions on the field, with white tricots resulting in the best location assessment. The outfit colour may indirectly influence football match results, warranting more attention to the home and away shirts by team managers and football scientists.

ULTRASONOGRAPHIC ASSESSMENT OF NECK MUSCULAR SIZE AND RANGE OF MOTION IN RUGBY PLAYERS

PubMed Central

Calistri, Josselin; Papadopoulou, Virginie; Theunissen, Sigrid; Dugardeyn, Christian; Balestra, Costantino

2018-01-01

Background World Rugby Union laws are constantly evolving towards stringent injury-prevention, particularly for contested scrums, since front row players are most at risk of cervical spine injuries. Recently, some countries have also introduced tailored training programs and minimum performance requirements for playing in the front row. Nevertheless, these approaches lack an objective assessment of each cervical muscle that would provide protective support. Objective Since front row players are the most at risk for cervical spine injuries due to the specific type of contact during scrums, the purpose of this study was to ascertain whether significant differences exist in neck muscle size and range of motion between front row players and players of other positions, across playing categories. Study Design Cross-sectional controlled laboratory study Methods 129 sub-elite male subjects from various first-team squads of Belgian Rugby clubs were recruited. Subjects were grouped according to age: Junior (J) < 19 years old, Senior (S) 19 to 35 years old and Veteran (V) > 35 years old; as well as playing position: Front row players (J = 10, S = 12, V = 11 subjects), (Rest of the) pack (J = 12, S = 12, V = 10), backs (J = 10, S = 11, V = 11). An age-matched control group of non-rugby players was also recruited (J = 10, S = 10, V = 10). For each subject, the total neck circumference (NC) and the cervical range of motion (CROM) were measured. In addition, the thickness of the trapezius (T), splenius capitis (SCa), semispinalis capitis (SCb), semispinalis cervicis (SPC), sternocleidomastoid muscles (SCOM), and the total thickness of all four structures (TT), were measured using ultrasonography. Results In each age category, compared to controls, rugby players were found to have decreased CROM, an increase in neck circumference (NC), and increased total thickness (TT), trapezius (T), semispinalis capitis (SCb) and sternocleidomastoid muscles (SCOM) sizes. For junior players, the thickness of the semispinalis cervicis (SPC) was also increased compared to controls. The CROM was decreased in front row players compared to pack and back players for all age categories; Front row seniors also showed an increase in trapezius (T), splenius capitis (SCa), semispinalis capitis (SCb) and total thickness (TT), compared to back players. Conclusion In regard of the differences in cervical values found between player positions, the implementation of both range of motion and echography muscle thickness assessments could serve to create an additional measurement for all front row players, that could complement current pre-participation screening used by rugby federations by objectively monitoring muscular size and motion amplitude around the cervical spine. PMID:29484239

Performance Assessment in Serious Games: Compensating for the Effects of Randomness

ERIC Educational Resources Information Center

Westera, Wim

2016-01-01

This paper is about performance assessment in serious games. We conceive serious gaming as a process of player-lead decision taking. Starting from combinatorics and item-response theory we provide an analytical model that makes explicit to what extent observed player performances (decisions) are blurred by chance processes (guessing behaviors). We…

Factors influencing tackle injuries in rugby union football

PubMed Central

Garraway, W. M.; Lee, A. J.; Macleod, D. A.; Telfer, J. W.; Deary, I. J.; Murray, G. D.

1999-01-01

OBJECTIVES: To assess the influence of selected aspects of lifestyle, personality, and other player related factors on injuries in the tackle. To describe the detailed circumstances in which these tackles occurred. METHODS: A prospective case-control study was undertaken in which the tackling and tackled players ("the cases") involved in a tackle injury were each matched with "control" players who held the same respective playing positions in the opposing teams. A total of 964 rugby matches involving 71 senior clubs drawn from all districts of the Scottish Rugby Union (SRU) were observed by nominated linkmen who administered self report questionnaires to the players identified as cases and controls. Information on lifestyle habits, match preparation, training, and coaching experience was obtained. A validated battery of psychological tests assessed players' trait anger and responses to anger and hostility. The circumstances of the tackles in which injury occurred were recorded by experienced SRU coaching staff in interviews with involved players after the match. RESULTS: A total of 71 tackle injury episodes with correct matching of cases and controls were studied. The following player related factors did not contribute significantly to tackle injuries: alcohol consumption before the match, feeling "below par" through minor illness, the extent of match preparation, previous coaching, or practising tackling. Injured and non- injured players in the tackle did not differ in their disposition toward, or expression of, anger or hostility. Some 85% of tackling players who were injured were three quarters, and 52% of injuries occurred when the tackle came in behind the tackled player or within his peripheral vision. Either the tackling or tackled player was sprinting or running in all of these injury episodes. One third of injuries occurred in differential speed tackles--that is, when one player was travelling much faster than the other at impact. The player with the lower momentum was injured in 80% of these cases. Forceful or crunching tackles resulting in injury mostly occurred head on or within the tackled player's side vision. CONCLUSIONS: Attention should be focused on high speed tackles going in behind the tackled player's line of vision. Comparative information on the circumstances of the vast majority of tackles in which no injury occurs is required before any changes are considered to reduce injuries in the tackle. 


 PMID:10027056

Multiple player tracking in sports video: a dual-mode two-way bayesian inference approach with progressive observation modeling.

PubMed

Xing, Junliang; Ai, Haizhou; Liu, Liwei; Lao, Shihong

2011-06-01

Multiple object tracking (MOT) is a very challenging task yet of fundamental importance for many practical applications. In this paper, we focus on the problem of tracking multiple players in sports video which is even more difficult due to the abrupt movements of players and their complex interactions. To handle the difficulties in this problem, we present a new MOT algorithm which contributes both in the observation modeling level and in the tracking strategy level. For the observation modeling, we develop a progressive observation modeling process that is able to provide strong tracking observations and greatly facilitate the tracking task. For the tracking strategy, we propose a dual-mode two-way Bayesian inference approach which dynamically switches between an offline general model and an online dedicated model to deal with single isolated object tracking and multiple occluded object tracking integrally by forward filtering and backward smoothing. Extensive experiments on different kinds of sports videos, including football, basketball, as well as hockey, demonstrate the effectiveness and efficiency of the proposed method.

Performance nutrition guidelines for international rugby sevens tournaments.

PubMed

Dziedzic, Christine E; Higham, Dean G

2014-06-01

Rugby sevens is an abbreviated version of rugby union, played by teams of seven players over 7-min halves. International competitions are usually played in a tournament format. While shorter in duration, the movement demands of rugby sevens per min of match time are greater than rugby union, resulting in an accentuated load on players. This load can be repeated up to six times over a typical 2- or 3-day competition period. The potential cumulative effect of inadequate carbohydrate, protein and/or fluid intake over the course of a tournament is the greatest nutrition-related concern for players. Nutritional strategies before and during competition are suggested to replenish substrate stores, maintain fluid balance and promote recovery between matches. The use of ergogenic aids known to enhance intermittent, high-intensity activity and/or the execution of motor skills may be advantageous to rugby sevens performance and is discussed. This review provides a best-practice model of nutritional support for international rugby sevens competition based on our current understanding of the sport combined with pragmatic guidelines and considerations for the practitioner.

ARC-2010-AD10-0106-015

NASA Image and Video Library

2010-06-07

Stephen Beitashour, a professional soccer player from the San Jose Earthquakes, was asked to demonstrate kicking the ball for his student audience. With the increased globalization of soccer, more young people are playing the sport and developing motor skills to compete effectively. To enhance their skills, students in the United States and Canada recently were given the opportunity to discuss with a NASA scientist the aerodynamics of the newly designed soccer ball. To help student soccer players better understand the movement of the ball, NASA scientists at the Fluid Mechanics Laboratory at NASA’s Ames Research Center, Moffett Field, Calif., recently tested the performance of the Jabulani design, and compared it to the 2006 design. Included in this study was Rabi Mehta who had done previous tests on tennis and cricket balls in wind tunnels.

The effect of biological movement variability on the performance of the golf swing in high- and low-handicapped players.

PubMed

Bradshaw, Elizabeth J; Keogh, Justin W L; Hume, Patria A; Maulder, Peter S; Nortje, Jacques; Marnewick, Michel

2009-06-01

The purpose of this study was to examine the role of neuromotor noise on golf swing performance in high- and low-handicap players. Selected two-dimensional kinematic measures of 20 male golfers (n=10 per high- or low-handicap group) performing 10 golf swings with a 5-iron club was obtained through video analysis. Neuromotor noise was calculated by deducting the standard error of the measurement from the coefficient of variation obtained from intra-individual analysis. Statistical methods included linear regression analysis and one-way analysis of variance using SPSS. Absolute invariance in the key technical positions (e.g., at the top of the backswing) of the golf swing appears to be a more favorable technique for skilled performance.

Ulnar nerve entrapment in a French horn player.

PubMed

Hoppmann, R A

1997-10-01

Nerve entrapment syndromes are frequent among musicians. Because of the demands on the musculoskeletal system and the great agility needed to per-form, musicians often present with vague complaints early in the course of entrapment, which makes the diagnosis a challenge for the clinician. Presented here is such a case of ulnar nerve entrapment at the left elbow of a French horn player. This case points out some of the difficulties in establishing a diagnosis of nerve entrapment in musicians. It also supports the theory that prolonged elbow flexion and repetitive finger movement contribute to the development of ulnar entrapment at the elbow. Although surgery is not required for most of the musculoskeletal problems of musicians, release of an entrapped nerve refractory to conservative therapy may be career-saving for the musician.

The Efficacy of Exergames Played Proximally and over the Internet on Cognitive Functioning for Online Physical Education

ERIC Educational Resources Information Center

Kooiman, Brian J.; Sheehan, Dwayne P.

2014-01-01

Exergames (active video games that require kinesthetic movement) played in proximity to other players or against a gaming machine have been linked to positive increases in cognitive functioning. This study tested to see if remote exergame play over the Internet had an impact similar to exergames that are played in proximity. The study shows that…

Grassroots Activists and the Three Branches of Government: "Key Players in the Civil Rights Movement"

ERIC Educational Resources Information Center

Brown, Elizabeth; Silvestri, Linda

2014-01-01

In order to understand the complex workings of the three branches of American government, young citizens need early exposure in the elementary years to hands-on lessons that include real life examples and opportunities for students to apply what they have learned. To that end, the authors designed a five-day, inquiry-based unit for fourth grade…

Futsal World Cup: Differences Created by Winning, Losing and Drawing Variables in Scored Goals and Offensive Variations

ERIC Educational Resources Information Center

Balyan, Melih; Vural, Faik

2018-01-01

Futsal, which can be defined as a new sports branch compared to football, has some shortcomings in comparison with football as well according to the studies carried out. Studies have rather focused on the movement characteristics of futsal players during the game and the physiological effects of games. On the other hand, there are only a limited…

Effects of prophylactic knee bracing on knee joint kinetics and kinematics during netball specific movements.

PubMed

Sinclair, Jonathan K; Vincent, Hayley; Richards, Jim D

2017-01-01

To investigate the effects of a prophylactic knee brace on knee joint kinetics and kinematics during netball specific movements. Repeated measures. Laboratory. Twenty university first team level female netball players. Participants performed three movements, run, cut and vertical jump under two conditions (brace and no-brace). 3-D knee joint kinetics and kinematics were measured using an eight-camera motion analysis system. Knee joint kinetics and kinematics were examined using 2 × 3 repeated measures ANOVA whilst the subjective ratings of comfort and stability were investigated using chi-squared tests. The results showed no differences (p > 0.05) in knee joint kinetics. However the internal/external rotation range of motion was significantly (p < 0.05) reduced when wearing the brace in all movements. The subjective ratings of stability revealed that netballers felt that the knee brace improved knee stability in all movements. Further study is required to determine whether reductions in transverse plane knee range of motion serve to attenuate the risk from injury in netballers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessing worst case scenarios in movement demands derived from global positioning systems during international rugby union matches: Rolling averages versus fixed length epochs.

PubMed

Cunningham, Daniel J; Shearer, David A; Carter, Neil; Drawer, Scott; Pollard, Ben; Bennett, Mark; Eager, Robin; Cook, Christian J; Farrell, John; Russell, Mark; Kilduff, Liam P

2018-01-01

The assessment of competitive movement demands in team sports has traditionally relied upon global positioning system (GPS) analyses presented as fixed-time epochs (e.g., 5-40 min). More recently, presenting game data as a rolling average has become prevalent due to concerns over a loss of sampling resolution associated with the windowing of data over fixed periods. Accordingly, this study compared rolling average (ROLL) and fixed-time (FIXED) epochs for quantifying the peak movement demands of international rugby union match-play as a function of playing position. Elite players from three different squads (n = 119) were monitored using 10 Hz GPS during 36 matches played in the 2014-2017 seasons. Players categorised broadly as forwards and backs, and then by positional sub-group (FR: front row, SR: second row, BR: back row, HB: half back, MF: midfield, B3: back three) were monitored during match-play for peak values of high-speed running (>5 m·s-1; HSR) and relative distance covered (m·min-1) over 60-300 s using two types of sample-epoch (ROLL, FIXED). Irrespective of the method used, as the epoch length increased, values for the intensity of running actions decreased (e.g., For the backs using the ROLL method, distance covered decreased from 177.4 ± 20.6 m·min-1 in the 60 s epoch to 107.5 ± 13.3 m·min-1 for the 300 s epoch). For the team as a whole, and irrespective of position, estimates of fixed effects indicated significant between-method differences across all time-points for both relative distance covered and HSR. Movement demands were underestimated consistently by FIXED versus ROLL with differences being most pronounced using 60 s epochs (95% CI HSR: -6.05 to -4.70 m·min-1, 95% CI distance: -18.45 to -16.43 m·min-1). For all HSR time epochs except one, all backs groups increased more (p < 0.01) from FIXED to ROLL than the forward groups. Linear mixed modelling of ROLL data highlighted that for HSR (except 60 s epoch), SR was the only group not significantly different to FR. For relative distance covered all other position groups were greater than the FR (p < 0.05). The FIXED method underestimated both relative distance (~11%) and HSR values (up to ~20%) compared to the ROLL method. These differences were exaggerated for the HSR variable in the backs position who covered the greatest HSR distance; highlighting important consideration for those implementing the FIXED method of analysis. The data provides coaches with a worst-case scenario reference on the running demands required for periods of 60-300 s in length. This information offers novel insight into game demands and can be used to inform the design of training games to increase specificity of preparation for the most demanding phases of matches.

When 'just doing it' is not enough: assessing the fidelity of player performance of an injury prevention exercise program.

PubMed

Fortington, Lauren V; Donaldson, Alex; Lathlean, Tim; Young, Warren B; Gabbe, Belinda J; Lloyd, David; Finch, Caroline F

2015-05-01

To obtain benefits from sports injury prevention programs, players are instructed to perform the exercises as prescribed. We developed an observational checklist to measure the quality of exercise performance by players participating in FootyFirst, a coach-led, exercise-based, lower-limb injury prevention program in community Australian Football (AF). Observational. The essential performance criteria for each FootyFirst exercise were described in terms of the technique, volume and intensity required to perform each exercise. An observational checklist was developed to evaluate each criterion through direct visual observation of players at training. The checklist was trialled by two independent raters who observed the same 70 players completing the exercises at eight clubs. Agreement between observers was assessed by Kappa-statistics. Exercise fidelity was defined as the proportion of observed players who performed all aspects of their exercises correctly. The raters agreed on 61/70 observations (87%) (Kappa=0.72, 95% CI: 0.55; 0.89). Of the observations with agreed ratings, 41 (67%) players were judged as performing the exercises as prescribed. The observational checklist demonstrated high inter-rater reliability. Many players observed did not perform the exercises as prescribed, raising concern as to whether they would be receiving anticipated program benefits. Where quality of exercise performance is important, evaluation and reporting of program fidelity should include direct observations of participants. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

A study of the effectiveness of MP3 players to support family carers of people living with dementia at home.

PubMed

Lewis, Virginia; Bauer, Michael; Winbolt, Margaret; Chenco, Carol; Hanley, Francine

2015-03-01

Music can be therapeutic to people with dementia; however, little is known about its effect on the family carers. This project aimed to (1) assess the effects of MP3 player use by a person with dementia on caregivers' mental health and wellbeing, including their self-care and health-promoting behavior and (2) determine whether MP3 player use increases caregivers' self-reported capacity to cope with their role. A pre-post quantitative and qualitative design was used. Carers completed a survey prior to commencing and four weeks after using the player. The survey included validated measures to assess the level of stress and coping among carers. Carers also kept a diary of the way they used the MP3 player. Half of the carers were interviewed about their experiences at the end of the study. Of 59 people who started using the MP3 player, 51 carers completed the four-week study period and surveys. Use of the MP3 player significantly decreased psychological distress, significantly improved the mental health and wellbeing of carers, significantly increased caregiver self-efficacy to manage symptoms of dementia, and was reported to provide valued respite from the high level of vigilance required for caring for a person with dementia. An MP3 player loaded with music can be a low cost and relatively simple and effective additional strategy to support families caring for people with dementia in the community.

Protective equipment use among female rugby players.

PubMed

Comstock, R Dawn; Fields, Sarah K; Knox, Christy L

2005-07-01

Our objective was to assess the prevalence of protective equipment use and the motivation for using protective equipment among a sample of US female rugby players. We surveyed a convenience sample of 234 current US female rugby players from 14 teams participating in a US women's rugby tournament, obtaining self-reported demographic, rugby exposure, and protective equipment use information. Mouthguards were the most commonly used piece of protective equipment: 90.8% of players reported having always worn a mouthguard while playing or practicing rugby within their most recent 3 months of play. Fewer than 15% of players reported having always worn other types of protective equipment. Equipment use varied by playing position. Whereas over 80% of players in all other positions always wore a mouthguard, 66.7% of scrum halves reported always wearing one. Both backs and forwards reported wearing shoulder pads, but only forwards reported always wearing padded headgear. Mouthguards, padded headgear, and shoulder pads were worn "to prevent injury," whereas ankle braces, neoprene sleeves, and athletic tape on joints were worn "to protect a current/recent injury." This is the first study of female rugby players to assess the prevalence of protective equipment use by playing position and the motivation for using protective equipment. With the exception of mouthguards, US female rugby players infrequently use protective equipment. Protective equipment use varies by playing position. Some types of protective equipment appear to be used as primary prevention mechanisms, whereas others are used as secondary or tertiary prevention mechanisms.

Knee movement patterns of injured and uninjured adolescent basketball players when landing from a jump: A case-control study

PubMed Central

Louw, Quinette; Grimmer, Karen; Vaughan, Christopher

2006-01-01

Background A common knee injury mechanism sustained during basketball is landing badly from a jump. Landing is a complex task and requires good coordination, dynamic muscle control and flexibility. For adolescents whose coordination and motor control has not fully matured, landing badly from a jump can present a significant risk for injury. There is currently limited biomechanical information regarding the lower limb kinetics of adolescents when jumping, specifically regarding jump kinematics comparing injured with uninjured adolescents. This study reports on an investigation of biomechanical differences in landing patterns of uninjured and injured adolescent basketball players. Methods A matched case-control study design was employed. Twenty-two basketball players aged 14–16 years participated in the study: eleven previously knee-injured and eleven uninjured players matched with cases for age, gender, weight, height and years of play, and playing for the same club. Six high-speed, three-dimensional Vicon 370 cameras (120 Hz), Vicon biomechanical software and SAS Version 8 software were employed to analyse landing patterns when subjects performed a "jump shot". Linear correlations determined functional relationships between the biomechanical performance of lower limb joints, and paired t-tests determined differences between the normalised peak biomechanical parameters. Results The average peak vertical ground reaction forces between the cases and controls were similar. The average peak ground reaction forces between the cases and controls were moderately correlated (r = -0.47). The control (uninjured) players had significantly greater hip and knee flexion angles and significantly greater eccentric activity on landing than the uninjured cases (p < 0.01). Conclusion The findings of the study indicate that players with a history of knee injuries had biomechanically compromised landing techniques when compared with uninjured players matched for gender, age and club. Descriptions (norms) of expected levels of knee control, proprioceptive acuity and eccentric strength relative to landing from a jump, at different ages and physical developmental stages, would assist clinicians and coaches to identify players with inappropriate knee performance comparable to their age or developmental stage. PMID:16522210

Water and salt balance in young male football players in training during the holy month of Ramadan.

PubMed

Shirreffs, Susan M; Maughan, Ronald J

2008-12-01

The aim of this study was to assess water and salt balance in young football players in training during Ramadan. Measurements were made in 92 young male football players before and during the month of Ramadan. Fifty-five participants were observing Ramadan fasting, while the other 37 participants were eating and drinking without restriction. In week 3 of Ramadan, water and salt balance measures were made during a training session of 60-70 min duration that was performed at an ambient temperature of 25-28 degrees C and relative humidity of 50-53%. Body mass was recorded before and after training. Fluid intake was assessed in non-fasting players by weighing drink bottles before and after training, and the volume of any urine output was recorded. Sweat composition was estimated from absorbent patches applied to four skin sites for the duration of training. Mean sweat loss of players amounted to 1.41 litres (s = 0.36) in fasting players and 1.61 litres (s = 0.51) in non-fasting players (P = 0.038). Mean fluid intake during training in non-fasting players was 1.92 litres (s = 0.66). Sweat sodium concentration was 20 mmol . l(-1) (s = 8) in fasting players and 17 mmol . l(-1) (s = 7) in non-fasting players, and total sweat sodium loss during training was 0.67 g (s = 0.41) and 0.65 g (s = 0.37) [corresponding to a salt loss of 1.7 g (s = 1.1) and 1.7 g (s = 0.9)] respectively, with no difference between fasting and non-fasting players. Sweat sodium loss was not related to estimated dietary sodium intake (r = -0.07). These descriptive data show large individual variations in all measured parameters with relatively little difference in sweat parameters between fasting and non-fasting individuals.

Intrinsic risk factors of noncontact ankle sprains in soccer: a prospective study on 100 professional players.

PubMed

Fousekis, Konstantinos; Tsepis, Elias; Vagenas, George

2012-08-01

Ankle sprain is an extremely common injury in soccer players. Despite extensive research, the intrinsic cause of this injury under noncontact conditions remains unclear. To identify intrinsic risk factors for noncontact ankle sprains in professional soccer players. Cohort study; Level of evidence, 2 One hundred professional soccer players were assessed in the preseason for potential risk factors of noncontact ankle sprains. The assessment included (A) ankle joint asymmetries (right-left) in isokinetic muscle strength, flexibility, proprioception, and stability; (B) somatometric asymmetries; (C) previous injuries; and (D) lateral dominance traits. Noncontact ankle sprains were prospectively recorded and diagnosed for a full competition period (10 months). Seventeen of the players sustained at least 1 noncontact ankle sprain. Logistic regression revealed that players with (A) eccentric isokinetic ankle flexion strength asymmetries (odds ratio [OR] = 8.88; 95% confidence interval [CI], 1.95-40.36, P = .005), (B) increased body mass index (OR = 8.16; 95% CI, 1.42-46.63, P = .018), and (C) increased body weight (OR = 5.72; 95% CI, 1.37-23.95, P = .017 ) each had a significantly higher risk of a noncontact ankle sprain. A trend for younger players (OR = 0.28; 95% CI, 0.061-1.24, P = .092) and for players with ankle laxity asymmetries (OR = 3.38; 95% CI, 0.82-14.00, P = .093) to be at greater risk for ankle sprain was also apparent to the limit of statistical significance (.05 < P < .10). Functional strength asymmetries of the ankle flexors and increased body mass index and body weight raise the propensity for ankle sprains in professional soccer players. Age and asymmetries in ankle laxity are potential factors worth revisiting, as there was an indication for younger players and players with ankle instability to be at higher risk for ankle injury. Proper preseason evaluation may improve prevention strategies for this type of injury in soccer.

Upper-body kinematics in team-handball throw, tennis serve, and volleyball spike.

PubMed

Wagner, H; Pfusterschmied, J; Tilp, M; Landlinger, J; von Duvillard, S P; Müller, E

2014-04-01

Overarm movements are essential skills in many different sport games; however, the adaptations to different sports are not well understood. The aim of the study was to analyze upper-body kinematics in the team-handball throw, tennis serve, and volleyball spike, and to calculate differences in the proximal-to-distal sequencing and joint movements. Three-dimensional kinematic data were analyzed via the Vicon motion capturing system. The subjects (elite players) were instructed to perform a team-handball jump throw, tennis serve, and volleyball spike with a maximal ball velocity and to hit a specific target. Significant differences (P < 0.05) between the three overarm movements were found in 17 of 24 variables. The order of the proximal-to-distal sequencing was equal in the three analyzed overarm movements. Equal order of the proximal-to-distal sequencing and similar angles in the acceleration phase suggest there is a general motor pattern in overarm movements. However, overarm movements appear to be modifiable in situations such as for throwing or hitting a ball with or without a racket, and due to differences at takeoff (with one or two legs). © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Multivariate analyses of individual variation in soccer skill as a tool for talent identification and development: utilising evolutionary theory in sports science.

PubMed

Wilson, Robbie S; James, Rob S; David, Gwendolyn; Hermann, Ecki; Morgan, Oliver J; Niehaus, Amanda C; Hunter, Andrew; Thake, Doug; Smith, Michelle D

2016-11-01

The development of a comprehensive protocol for quantifying soccer-specific skill could markedly improve both talent identification and development. Surprisingly, most protocols for talent identification in soccer still focus on the more generic athletic attributes of team sports, such as speed, strength, agility and endurance, rather than on a player's technical skills. We used a multivariate methodology borrowed from evolutionary analyses of adaptation to develop our quantitative assessment of individual soccer-specific skill. We tested the performance of 40 individual academy-level players in eight different soccer-specific tasks across an age range of 13-18 years old. We first quantified the repeatability of each skill performance then explored the effects of age on soccer-specific skill, correlations between each of the pairs of skill tasks independent of age, and finally developed an individual metric of overall skill performance that could be easily used by coaches. All of our measured traits were highly repeatable when assessed over a short period and we found that an individual's overall skill - as well as their performance in their best task - was strongly positively correlated with age. Most importantly, our study established a simple but comprehensive methodology for assessing skill performance in soccer players, thus allowing coaches to rapidly assess the relative abilities of their players, identify promising youths and work on eliminating skill deficits in players.

Effects of heavy episodic drinking on physical performance in club level rugby union players.

PubMed

Prentice, Christopher; Stannard, Stephen R; Barnes, Matthew J

2015-05-01

This study investigated the effects of acute alcohol consumption, in a natural setting, on exercise performance in the 2 days after the drinking episode. Additionally, alcohol related behaviours of this group of rugby players were identified. Prospective cohort study. Nineteen male club rugby players volunteered for this study. Measures of counter movement jump, maximal lower body strength, repeated sprint ability and hydration were made 2 days before and in the 2 days following heavy episodic alcohol consumption. Participants completed a questionnaire at each time point so that alcohol consumption and sleep hours from the previous 24 h period could be quantified. Additionally, participants completed the Alcohol Use Disorders Test (AUDIT) prior to completing baseline measures of performance. Reported alcohol consumption ranged from 6 to >20 standard drinks (mean category scale score=11-19 standard drinks). A significant decrease in sleep hours (p=0.01) was reported after the drinking episode with participants reporting 1-3 h for the night. A significant reduction (-1.8±1.5 cm) in counter movement jump (p<0.01) the morning after the drinking episode was observed; no other measures were altered at any time point compared to baseline (p>0.05). AUDIT scores for this group (18.2±4.3) indicate regular alcohol consumption at a hazardous level. Heavy episodic alcohol use, and associated reduced sleep hours, results in a reduction in lower body power output but not other measures of anaerobic performance the morning after a drinking session. Full recovery from this behaviour is achieved by 2 days post drinking episode. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Ice Hockey Players Using a Weighted Implement when Training on the Ice: A Randomized Control Trial

ERIC Educational Resources Information Center

Stark, Timothy W.; Tvoric, Bojan; Walker, Bruce; Noonan, Dom; Sibla, Janeene

2009-01-01

The purpose of this study was to investigate the potential for improving hockey players' performance using a weighted implement on the ice. Forty-eight players were tested using a grip strength dynamometer. They also were assessed on their abilities to stick-handle. The participants were randomly placed into a control or research group. The…

Test-retest reliability and agreement of the SPI-Questionnaire to detect symptoms of digital ischemia in elite volleyball players.

PubMed

van de Pol, Daan; Zacharian, Tigran; Maas, Mario; Kuijer, P Paul F M

2017-06-01

The Shoulder posterior circumflex humeral artery Pathology and digital Ischemia - questionnaire (SPI-Q) has been developed to enable periodic surveillance of elite volleyball players, who are at risk for digital ischemia. Prior to implementation, assessing reliability is mandatory. Therefore, the test-retest reliability and agreement of the SPI-Q were evaluated among the population at risk. A questionnaire survey was performed with a 2-week interval among 65 elite male volleyball players assessing symptoms of cold, pale and blue digits in the dominant hand during or after practice or competition using a 4-point Likert scale (never, sometimes, often and always). Kappa (κ) and percentage of agreement (POA) were calculated for individual symptoms, and to distinguish symptomatic and asymptomatic players. For the individual symptoms, κ ranged from "poor" (0.25) to "good" (0.63), and POA ranged from "moderate" (78%) to "good" (97%). To classify symptomatic players, the SPI-Q showed "good" reliability (κ = 0.83; 95%CI 0.69-0.97) and "good" agreement (POA = 92%). The current study has proven the SPI-Q to be reliable for detecting elite male indoor volleyball players with symptoms of digital ischemia.

Prevalence of tinea pedis in professional and college soccer players versus non-athletes.

PubMed

Pickup, Tiffany L; Adams, Brian B

2007-01-01

To assess and compare the prevalence of tinea pedis among professional soccer players, college soccer players, and non-athletes. We sought to assess the prevalence of various risk factors and their association with tinea pedis among these different groups. Survey study. United States. Members of a United Soccer League (USL) professional team (N = 16), male (N = 16) and female (N = 14) NCAA soccer teams at a local college, and male (N = 15) and female (N = 15) non-athletes from a local medical school. All participants anonymously answered questions on their risk factors for tinea pedis and underwent physical and mycological examinations. Clinical exam, potassium hydroxide solution (KOH), and culture. Tinea pedis infected 69% professional soccer players (11 of 16) compared with 69% of male college soccer players (11 of 16) and 43% of female college soccer players (6 of 14), whereas non-athletes demonstrated significantly less tinea pedis (P < 0.001), including 20% of male non-athletes (3 of 15) and 0% of female non-athletes (0 of 15). These results indicate a need for improved primary prevention of tinea pedis among athletes. A preventive program involving education and coach participation is needed to target these individuals.

New Zealand rugby health study: motor cortex excitability in retired elite and community level rugby players.

PubMed

Lewis, Gwyn N; Hume, Patria A; Stavric, Verna; Brown, Scott R; Taylor, Denise

2017-01-13

Rugby union is a high contact sport in which players frequently experience brain injuries. Acute brain injury is associated with altered corticomotor function. However, it is uncertain if long-term exposure to rugby is associated with any alterations in corticomotor function. The aim of the study was to assess measures of corticomotor excitability and inhibition in retired rugby players in comparison to retired non-contact sport players. The design was a cross-sectional study with three groups of retired athletes: elite rugby (n=23), community level rugby (n=28) and non-contact sport control (n=22). Assessments of corticomotor excitability were made using transcranial magnetic stimulation. Resting motor threshold was significantly higher and long-interval intracortical inhibition was greater in the elite rugby group compared to the control group. Participants in the two rugby groups had sustained significantly more concussions than the control group. We provide some evidence of altered corticomotor excitation and inhibition in retired elite rugby players in comparison to retired non-contact sport players. Given the absence of findings in the community rugby group, who had experienced a similar number of concussions, the association with previous brain injury is unclear.

The cervical spine of professional front-row rugby players: correlation between degenerative changes and symptoms.

PubMed

Hogan, B A; Hogan, N A; Vos, P M; Eustace, S J; Kenny, P J

2010-06-01

Injuries to the cervical spine (C-spine) are among the most serious in rugby and are well documented. Front-row players are particularly at risk due to repetitive high-intensity collisions in the scrum. This study evaluates degenerative changes of the C-spine and associated symptomatology in front-row rugby players. C-spine radiographs from 14 professional rugby players and controls were compared. Players averaged 23 years of playing competitive rugby. Two consultant radiologists performed a blind review of radiographs evaluating degeneration of disc spaces and apophyseal joints. Clinical status was assessed using a modified AAOS/NASS/COSS cervical spine outcomes questionnaire. Front-row rugby players exhibited significant radiographic evidence of C-spine degenerative changes compared to the non-rugby playing controls (P < 0.005). Despite these findings the rugby players did not exhibit increased symptoms. This highlights the radiologic degenerative changes of the C-spine of front-row rugby players. However, these changes do not manifest themselves clinically or affect activities of daily living.

Decreased shoulder function and pain common in recreational badminton players.

PubMed

Fahlström, M; Söderman, K

2007-06-01

The aim of this study was to describe the prevalence and consequences of painful conditions in the shoulder region in recreational badminton players. A questionnaire study was performed on 99 players, of whom 57 were also assessed with Constant score. Previous or present pain in the dominant shoulder was reported by 52% of the players. Sixteen percent of the players had on-going shoulder pain associated with badminton play. A majority of these players reported that their training habits were affected by the pain. Total Constant score was lower in the painful shoulders. Furthermore, range of active pain-free shoulder abduction was decreased. However, isometric shoulder strength test showed no differences when compared with pain-free shoulders. Even though the pain caused functional problems, the players were still playing with on-going symptoms. The diagnoses were mostly unknown, although history and clinical tests indicate problems resembling subacromial impingement.

Comparison of shuttle and straight repeated-sprint ability tests and their relationship to anthropometrics and explosive muscular performance of lower limb in elite handball players.

PubMed

Hermassi, Souhail; Schwesig, René; Wollny, Rainer; Fieseler, Georg; van den Tillaar, Roland; Fernandez-Fernandez, Jaime; Shephard, Roy J; Chelly, Mohamed S

2017-06-21

This study assessed inter-relationships between shuttle and straight repeated-sprint ability tests and the relationship of each measure to anthropometric and explosive lower limb performance data in elite handball players. Twenty-two elite male handball players (18.9 ± 0.2 years; body mass: 83.3 ± 1.1 kg, height: 1.79 ± 2.30 m, body fat: 12.8 ± 0.2%) completed tests that included a lower limb force-velocity test of peak power (Wpeak), jumping ability (squat and counter-movement jumps; SJ, CMJ), 1 repetition maximum (1-RM) half back squat, average sprint velocity over 5 m (V-5 m), peak velocity between 25-30 m (Vmax), and Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), and anthropometric determinations of cross-sectional areas and muscle volumes for leg and thigh muscles. Data were compared with performance on 2 repeated sprint tests; the straight test [6 × 30 m (RSA30)] and the intermittent test [6 x (2 x 15 m) shuttle sprints (RSA15)]. V-5 m; 1-RM; and thigh and leg muscle cross-sectional areas and volumes showed relevant relationships to the shuttle RSA test (r2≥0.5). The Yo-Yo IR1 explained the largest percentage of variance in RSA15 total time (60%), and V-5 m also explained 56% of the variance in RSA15 total time. RSA15% fatigue was only related to 1-RM (explained variance: 58%), and the RSA30 test showed no useful correlations with any of the investigated predictors. Multiple-regression analyses using all physical tests explained 91% of the variance in RSA15 total time (p<0.001). The volume of the leg muscles seems important to power production and repeated sprints over distances of 15 m or less. RSA15 is related to muscular power, maximal strength, speed and endurance performance; however, the straight repeated sprint ability test is not, and thus does not seem relevant for the testing of handball players.

Kinematic Analysis of Line-Out Throwing in Elite International Rugby Union

PubMed Central

Sayers, Mark G.L.

2011-01-01

The rugby union line-out is a key aspect of game play and involves players from both teams contesting for the ball after it has been thrown in from the side line. Successful lines-out throws require the ball to be delivered accurately to the hands of a jumping and/or lifted team mate (approximately 3-3.5 m off the ground) over distances of between 5- 18 m. Previous research has suggested considerable inter and intra-individual differences in the throwing techniques of international level players. Accordingly, this project investigated the interrelationships between accuracy and the line-out throwing characteristics of three elite international rugby players, and then analyzed whether these changed for throws over increasing length. Three-dimensional (3D) data were developed from video footage (50 Hz) of three elite international subjects for 30 throws over three distances (6 m, 10 m, and 15 m). Results showed notable differences between subjects in many variables at each of the key throw phases. However, several variables such as the degree of trunk flexion at the end of the backswing and at ball release, coupled with elbow flexion angle at ball release remained constant as throw length increased. All subjects exhibited high levels of consistency in movement patterns across all throw lengths. Findings indicated that these high performance line-out throwers shared several common characteristics that will provide useful guides in the development of training programs. Key points A key aspect of this research was the assessment of throwing accuracy using a functional throwing task that mimicked normal performance. Although individual differences in throwing technique occurred, several technical aspects of the throw were common to each of these elite international players. Subjects tended to be extremely consistent in the way they positioned the ball at the end of the backswing, and had very consistent elbow (flexion) and shoulder (flexion and abduction) angles at both the end of the backswing and at ball release. In addition, throwers kept the trunk close to upright during the throw with minimal trunk flexion or extension regardless of throw distance. To throw for longer distances participants tended to increase the involvement of the legs. PMID:24150632

Sensorimotor Control of the Shoulder in Professional Volleyball Players with Isolated Infraspinatus Muscle Atrophy.

PubMed

Contemori, Samuele; Biscarini, Andrea; Botti, Fabio Massimo; Busti, Daniele; Panichi, Roberto; Pettorossi, Vito Enrico

2017-06-12

Isolated infraspinatus muscle atrophy (IIMA) only affects the hitting shoulder of overhead-activity athletes, and is caused by suprascapular nerve neuropathy. No study has assessed the static and dynamic stability of the shoulder in overhead professional athletes with IIMA to reveal possible shoulder sensorimotor alterations. To assess the shoulder static stability, dynamic stability, and strength in professional volleyball players with IIMA and in healthy control players. Cross-sectional study. Research laboratory. Twenty-four male professional volleyball players (12 players with diagnosed IIMA and 12 healthy players) recruited from local volleyball teams. Static stability was evaluated with two independent force platforms and dynamic stability was assessed with the "Upper Quarter Y Balance Test". The static stability assessment was conducted in different support (single hand and both hand) and vision (open and closed eyes) conditions. Data from each test were analyzed with ANOVA and paired t-test models, to highlight statistical differences within and between groups. In addition to reduced abduction and external rotation strength, athletes with IIMA consistently demonstrated significant less static (P < 0.001) and dynamic stability (P < 0,001), compared with the contralateral shoulder and with healthy athletes. Closed eyes condition significantly enhanced the static stability deficit of the shoulder with IIMA (P = 0.039 and P = 0.034 for both hand and single hand support, respectively), but had no effect in healthy contralateral and healthy players' shoulders. This study highlights an impairment of the sensorimotor control system of the shoulder with IIMA, which likely results from both proprioceptive and strength deficits. This condition could yield subtle alteration in the functional use of the shoulder and predispose it to acute or overuse injuries. The results of this study may help athletic trainers and physical/physiotherapists to prevent shoulder injuries and create specific proprioceptive and neuromuscular training programs.

Differences in game reading between selected and non-selected youth soccer players.

PubMed

Den Hartigh, Ruud J R; Van Der Steen, Steffie; Hakvoort, Bas; Frencken, Wouter G P; Lemmink, Koen A P M

2018-02-01

Applying an established theory of cognitive development-Skill Theory-the current study compares the game-reading skills of youth players selected for a soccer school of a professional soccer club (n = 49) and their non-selected peers (n = 38). Participants described the actions taking place in videos of soccer game plays, and their verbalisations were coded using Skill Theory. Compared to the non-selected players, the selected players generally demonstrated higher levels of complexity in their game-reading, and structured the information of game elements-primarily the player, teammate and field-at higher complexity levels. These results demonstrate how Skill Theory can be used to assess, and distinguish game-reading of youth players with different expertise, a skill important for soccer, but also for other sports.

"White men can't jump." But can they throw? Social perception in European basketball.

PubMed

Furley, P; Dicks, M

2014-10-01

In the present article, we investigate the influence of sociocultural stereotypes on the impression formation of basketball players and coaches. In Experiment 1 (n = 32), participants were shown a picture of a black or white basketball player prior to observation of a point-light video of a player executing a basketball free throw. The participant was informed that the player depicted in the picture was executing the free throw. Results indicated that ethnicity of the target player significantly influenced participant evaluations, demonstrating specific stereotypes about black and white basketball players when evaluating performance. In Experiment 2 (n = 30), results derived from the Implicit Association Test indicated that black players are implicitly associated with athletic player attributes. The results are in line with social schema theory and demonstrate that - similar to findings that have been reported in the United States - a subpopulation of German basketball players and coaches hold specific stereotypes about the abilities of black and white basketball athletes. These stereotypes bias impression formation when coaches and players make assessments of basketball performance. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The contribution of situational probability information to anticipatory skill.

PubMed

Farrow, Damian; Reid, Machar

2012-07-01

To determine the contribution of situational probability information to the anticipatory responses of skilled tennis players representative of two different stages of development. Participants were required to predict the location of tennis serves presented to them on a plasma touchscreen from the perspective of the receiver. Serves were sequenced into a series of games and sets with a score presented before each point, typical of a game of tennis. The game score was manipulated to provide advance probability information. The location of the serve for the first point of each game was always directed to the same location. A total of 12 service games consisting of 96 points were presented with interest in whether players would detect the relationship between the game score and resultant serve location. A 2×12 (age×service game) ANOVA with repeated measures on the second factor revealed a significant age by service game interaction for response time (F₁₁,₂₉₇=3.86, p<0.05, η(p)²=.12). The older players picked up the occurrence of the first point service pattern after the ninth service game whereas the younger, players did not. There were no significant response accuracy differences between the groups in relation to the first point. The findings highlight the important role of situational probability information, in addition to movement kinematics, for successful anticipatory performance and suggest that the pick-up of such information is not utilised by younger players. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of Environmental Context on Physiological Response During Team Handball Small Sided Games.

PubMed

Bělka, Jan; Hulka, Karel; Machová, Iva; Šafář, Michal; Weisser, Radim; Bellar, David M; Hoover, Donald L; Judge, Lawrence W

2017-01-01

This study examined the distance covered and physiological effects of altering the number of players during small-sided games (SSG) in team handball. Twelve professional female handball players [24.6±3.7 years, 172±6.2 cm, 68.2 ± 9.9kg, 22.7 ± 2 kg/m 2 ] participated in this study. The SSG were played, first with five on each side (SSG 5), then four (SSG 4), then three (SSG 3). Each game was four minutes long, followed by three minutes of rest. The distance covered and time spent in four speed zones (based on player movement speed) were selected for analysis: Zone 1 (0-1.4 m/s), Zone 2 (1.5-3.4 m/s), Zone 3 (3.5-5.2 m/s), and Zone 4 (>5.2 m/s). Statistically significant differences were found in Zone 2, between conditions SSG 3 and SSG 4 (p=.049,ω 2 = .32). The highest average heart rate (HR) occurred during SSG 3. Average HR between SSG 3 (89.7 % HRmax) and SSG 5 (87.8 % HRmax) (p= .04, ω2= .26) were also significantly different. Participant HR response between the speed zones was not statistically significant. HR response was negatively correlated with the number of players within the SSG condition. Statistically significant results were found for RPE between SSG 3 and the other two SSG conditions (SSG 4, p = .01, and SSG 5, p = .00). These results indicate that changing the number of SSG players can be used to manipulate the physiological response during handball training.

Effects of Environmental Context on Physiological Response During Team Handball Small Sided Games

PubMed Central

BĚLKA, JAN; HULKA, KAREL; MACHOVÁ, IVA; ŠAFÁŘ, MICHAL; WEISSER, RADIM; BELLAR, DAVID M.; HOOVER, DONALD L; JUDGE, LAWRENCE W.

2017-01-01

This study examined the distance covered and physiological effects of altering the number of players during small-sided games (SSG) in team handball. Twelve professional female handball players [24.6±3.7 years, 172±6.2 cm, 68.2 ± 9.9kg, 22.7 ± 2 kg/m2] participated in this study. The SSG were played, first with five on each side (SSG 5), then four (SSG 4), then three (SSG 3). Each game was four minutes long, followed by three minutes of rest. The distance covered and time spent in four speed zones (based on player movement speed) were selected for analysis: Zone 1 (0–1.4 m/s), Zone 2 (1.5–3.4 m/s), Zone 3 (3.5–5.2 m/s), and Zone 4 (>5.2 m/s). Statistically significant differences were found in Zone 2, between conditions SSG 3 and SSG 4 (p=.049,ω2= .32). The highest average heart rate (HR) occurred during SSG 3. Average HR between SSG 3 (89.7 % HRmax) and SSG 5 (87.8 % HRmax) (p= .04, ω2= .26) were also significantly different. Participant HR response between the speed zones was not statistically significant. HR response was negatively correlated with the number of players within the SSG condition. Statistically significant results were found for RPE between SSG 3 and the other two SSG conditions (SSG 4, p = .01, and SSG 5, p = .00). These results indicate that changing the number of SSG players can be used to manipulate the physiological response during handball training. PMID:29399252

Play in adult bonobos (Pan paniscus): modality and potential meaning.

PubMed

Palagi, Elisabetta; Paoli, Tommaso

2007-10-01

The aim of this study was to thoroughly investigate social play and its modalities among adult bonobos. We evaluated how play intensity varies according to the sex-class combination of the playmates and we also performed an analysis on social locomotor-rotational movements (L-R play) and contact interactions (C play). Rough and gentle play sessions were performed with comparable frequencies by male-female and female-female adult dyads, with play signals unlikely when the playmates strongly differed in age and in rank position. L-R play rates did not differ according to the sex-combination of the players; in contrast, C play sessions were particularly frequent among females. Play faces (play signals) were significantly higher during C play than L-R play sessions, thus suggesting that playmates assess reciprocally yet safely their relationships by using facial displays to avoid any kind of misunderstanding. Play was positively correlated with grooming and contact sitting interactions, suggesting that it may be used as a social enhancer. Finally, we found no correlation between both play contexts (L-R and C play) and age, size and rank differences of the players. In conclusion, we suggest that bonobos with their egalitarian society, peculiar social structure, and playful tendency represent an attractive testing subject to examine empirically many emerging hypotheses on adult play behavior. (c) 2007 Wiley-Liss, Inc.

The New Zealand rugby injury and performance project. III. Anthropometric and physical performance characteristics of players.

PubMed Central

Quarrie, K L; Handcock, P; Waller, A E; Chalmers, D J; Toomey, M J; Wilson, B D

1995-01-01

OBJECTIVE: To investigate the anthropometric and physical performance characteristics of New Zealand rugby players of different ages and both sexes. METHODS: 356 rugby players (264 male, 92 female) took part in the study during a single season. Playing grade ranged from schoolboys and schoolgirls to senior men and women. Assessment of height, weight, neck circumference, and somatotype was performed before the competitive rugby season. A battery of six physical performance assessments was completed after the anthropometry. Analysis of variance was used to examine differences in these variables between field positions and grades. RESULTS: Significant differences between forwards and backs on anthropometric and physical performance variables were apparent at all grades assessed. In terms of anthropometric characteristics, forwards of a given grade were generally taller, possessed greater body mass, and were more endomorphic and less ectomorphic than backs of the same grade. The backs tended to perform better on physical performance measures than forwards, being more aerobically fit, faster, more agile, and possessing a higher degree of muscular endurance. Differences in anthropometry and physical performance attributes were also apparent between players from the various grades. The players at higher levels were generally larger, and performed better on tests of physical performance than the players at lower levels. These differences were found in both sexes. CONCLUSIONS: The greater body mass of the forwards allows them to obtain greater momentum than the backs when sprinting. The ability to obtain greater momentum is important in the body contact phases of the game. Forwards may compromise their aerobic fitness and speed to some extent in order to maintain a high body mass. The anthropometric and physical performance characteristics of players appear to reflect the demands placed on them by the sport. PMID:8808542

The association between hip and groin injuries in the elite junior football years and injuries sustained during elite senior competition.

PubMed

Gabbe, B J; Bailey, M; Cook, J L; Makdissi, M; Scase, E; Ames, N; Wood, T; McNeil, J J; Orchard, J W

2010-09-01

To establish the relationship between the history of hip and groin injuries in elite junior football players prior to elite club recruitment and the incidence of hip and groin injuries during their elite career. Retrospective cohort study. Analysis of existing data. 500 Australian Football League (AFL) players drafted from 1999 to 2006 with complete draft medical assessment data. Previous history of hip/groin injury, anthropometric and demographic information. The number of hip/groin injuries resulting in > or =1 missed AFL game. Data for 500 players were available for analysis. 86 (17%) players reported a hip/groin injury in their junior football years. 159 (32%) players sustained a hip/groin injury in the AFL. Players who reported a previous hip or groin injury at the draft medical assessment demonstrated a rate of hip/groin injury in the AFL >6 times higher (IRR 6.24, 95% CI 4.43 to 8.77) than players without a pre-AFL hip or groin injury history. This study demonstrated that a hip or groin injury sustained during junior football years is a significant predictor of missed game time at the elite level due to hip/groin injury. The elite junior football period should be targeted for research to investigate and identify modifiable risk factors for the development of hip/groin injuries.

The role of physiology in the development of golf performance.

PubMed

Smith, Mark F

2010-08-01

The attainment of consistent high performance in golf requires effective physical conditioning that is carefully designed and monitored in accordance with the on-course demands the player will encounter. Appreciating the role that physiology plays in the attainment of consistent performance, and how a player's physicality can inhibit performance progression, supports the notion that the application of physiology is fundamental for any player wishing to excel in golf. With cardiorespiratory, metabolic, hormonal, musculoskeletal and nutritional demands acting on the golfer within and between rounds, effective physical screening of a player will ensure physiological and anatomical deficiencies that may influence performance are highlighted. The application of appropriate golf-specific assessment methods will ensure that physical attributes that have a direct effect on golf performance can be measured reliably and accurately. With the physical development of golf performance being achieved through a process of conditioning with the purpose of inducing changes in structural and metabolic functions, training must focus on foundation whole-body fitness and golf-specific functional strength and flexibility activities. For long-term player improvement to be effective, comprehensive monitoring will ensure the player reaches an optimal physical state at predetermined times in the competitive season. Through continual assessment of a player's physical attributes, training effectiveness and suitability, and the associated adaptive responses, key physical factors that may impact most on performance success can be determined.

A new physical performance classification system for elite handball players: cluster analysis

PubMed Central

Chirosa, Ignacio J.; Robinson, Joseph E.; van der Tillaar, Roland; Chirosa, Luis J.; Martín, Isidoro Martínez

2016-01-01

Abstract The aim of the present study was to identify different cluster groups of handball players according to their physical performance level assessed in a series of physical assessments, which could then be used to design a training program based on individual strengths and weaknesses, and to determine which of these variables best identified elite performance in a group of under-19 [U19] national level handball players. Players of the U19 National Handball team (n=16) performed a set of tests to determine: 10 m (ST10) and 20 m (ST20) sprint time, ball release velocity (BRv), countermovement jump (CMJ) height and squat jump (SJ) height. All players also performed an incremental-load bench press test to determine the 1 repetition maximum (1RMest), the load corresponding to maximum mean power (LoadMP), the mean propulsive phase power at LoadMP (PMPPMP) and the peak power at LoadMP (PPEAKMP). Cluster analyses of the test results generated four groupings of players. The variables best able to discriminate physical performance were BRv, ST20, 1RMest, PPEAKMP and PMPPMP. These variables could help coaches identify talent or monitor the physical performance of athletes in their team. Each cluster of players has a particular weakness related to physical performance and therefore, the cluster results can be applied to a specific training programmed based on individual needs. PMID:28149376

Effects of public posting, goal setting, and oral feedback on the skills of female soccer players.

PubMed

Brobst, Brandilea; Ward, Phillip

2002-01-01

We evaluated the effects of public posting, goal setting, and oral feedback on the skills of 3 female high school soccer players during practice scrimmages. The dependent variables were the percentage of appropriate responses when the player (a) kept and maintained possession of the ball, (b) moved to an open position during a game restart (e.g., goal or corner kick), and (c) moved to an open position after passing the ball. We also assessed the extent to which changes in practice performances generalized to games. A social validity questionnaire was completed by both players and coaches to assess the acceptability of the intervention's goals, procedures, and outcomes. Results indicate that the intervention was effective in improving performances during practice scrimmages but produced limited generalization to game settings.

Effects of public posting, goal setting, and oral feedback on the skills of female soccer players.

PubMed Central

Brobst, Brandilea; Ward, Phillip

2002-01-01

We evaluated the effects of public posting, goal setting, and oral feedback on the skills of 3 female high school soccer players during practice scrimmages. The dependent variables were the percentage of appropriate responses when the player (a) kept and maintained possession of the ball, (b) moved to an open position during a game restart (e.g., goal or corner kick), and (c) moved to an open position after passing the ball. We also assessed the extent to which changes in practice performances generalized to games. A social validity questionnaire was completed by both players and coaches to assess the acceptability of the intervention's goals, procedures, and outcomes. Results indicate that the intervention was effective in improving performances during practice scrimmages but produced limited generalization to game settings. PMID:12365738

Gender as a variable in the assessment of final year degree-level communication skills.

PubMed

Wiskin, Connie M D; Allan, Teresa F; Skelton, John R

2004-02-01

To investigate possible bias due to gender combination of students, role players and examiners in a high-stakes assessment. Valid oral interactive contextualized examinations (VOICEs) is a long-station OSCE-style exam in general practice (GP). At the time of writing it consisted of 65% of the student's final GP mark. In the VOICE, students undertake six tasks--four vivas and two role-plays. "Patient" roles are taken by professional role players who work regularly on the undergraduate curriculum. During the role-play, the student's clinical competence is assessed by an observing GP examiner. The communication skills marks are awarded by the role player and the examiner together, by negotiation. Data have been recorded detailing the role player's initial marks, the examiner's initial marks and their final (awarded) agreed marks for 1024 consultations. 512 final year medical students, 28 role players and 48 examiners. There were no inclusion or exclusion criteria. All those present on exam day became part of the data. There was a significant relationship between gender and performance for some, but not all, stations. Correlations for multiple comparisons removed the significance. Female students perform better across the board than male students. While not always significant, this did affect grading. There was no significant association between the genders of role players and examiners with the question choices. There has been a significant worsening of male results since 1999. Differences exist in the way that pairs of mixed or single genders score students.

Preseason Strength Assessment of the Rotator Muscles and Shoulder Injury in Handball Players.

PubMed

Forthomme, Bénédicte; Croisier, Jean-Louis; Delvaux, François; Kaux, Jean-François; Crielaard, Jean-Michel; Gleizes-Cervera, Sophie

2018-02-01

  Few researchers have identified intrinsic risk factors for shoulder injury in team handball players by analyzing measurements of maximal isokinetic rotator muscle strength.   To identify possible intrinsic risk factors for shoulder injury by analyzing measurements of maximal isokinetic rotator muscle strength.   Cross-sectional study.   Male team handball senior divisions (the highest level) in France and Belgium.   A total of 108 male high-level handball players (age = 24 ± 4 years, height = 189 ± 6 cm, mass = 87 ± 11 kg) were enrolled.   All players completed a preseason questionnaire and performed a bilateral isokinetic assessment of the shoulder rotator muscles. On a monthly questionnaire, players reported any shoulder injury that they sustained during the season.   On the preseason questionnaire, 51 of 108 (47%) participants reported a history of dominant-shoulder injury. A total of 106 participants completed the in-season questionnaire, with 22% (n = 23) reporting a shoulder injury on their dominant side during the subsequent season. Fourteen percent (n = 15) sustained microtraumatic injuries, and 8% (n = 8) described a traumatic injury. Backcourt players had a 3.5-times increased risk of injury during the new season compared with players in other positions. Among the isokinetic results, no risk factor for further injury was identified in handball players with microtraumatic injuries. For traumatic injuries, the concentric maximal strength developed by the internal rotators at high speed (240°/s) in the dominant shoulder was a protective factor against the risk of further injury.   These results can potentially identify intrinsic risk factors for shoulder injury and may be used to determine potential interventions for reducing this risk in handball players.

Analysis of Injury Incidences in Male Professional Adult and Elite Youth Soccer Players: A Systematic Review.

PubMed

Pfirrmann, Daniel; Herbst, Mark; Ingelfinger, Patrick; Simon, Perikles; Tug, Suzan

2016-05-01

The incidence of injury for elite youth and professional adult soccer players is an important concern, but the risk factors for these groups are different. To summarize and compare the injury incidences and injury characteristics of male professional adult and elite youth soccer players. We searched MEDLINE and Web of Science using the search terms elite, international, European, soccer, football, injury, injuries, epidemiology, incidence, prevalence, not female, not American football, and not rugby. We also used the search terms professional for studies on professional adult soccer players and high-level, soccer academy, youth, adolescent, and young for studies on elite youth soccer players. Eligible studies were published in English, had a prospective cohort design, and had a minimum study period of 6 months. To ensure that injury data were assessed in relationship to the athlete's individual exposure, we included only studies that reported on injuries and documented exposure volume. Two independent reviewers applied the selection criteria and assessed the quality of the studies. A total of 676 studies were retrieved from the literature search. Eighteen articles met the inclusion criteria: 6 for elite youth and 12 for professional adult soccer players. Injury rates were higher for matches than for training for both youth and adult players. Youth players had a higher incidence of training injuries than professionals. Efforts must be made to reduce the overall injury rate in matches. Therefore, preventive interventions, such as adequately enforcing rules and focusing on fair play, must be analyzed and developed to reduce match-related injury incidences. Reducing training injuries should be a particular focus for youth soccer players.

Comparison of physical performance among Brazilian elite soccer players of different age-categories.

PubMed

Kobal, Ronaldo; Loturco, Irineu; Gil, Saulo; Cal Abad, Cesar C; Cuniyochi, Rogério; Barroso, Renato; Tricoli, Valmor

2016-04-01

The purpose of this study was to compare the physical performance (i.e., strength, power, speed and endurance) between Brazilian elite soccer players from different categories of the same club: professionals (PRO), under-20 (U-20), and under-17 (U-17). Seventy-one soccer players from three categories (PRO=24; U-20=21 and U-17=26) were assessed at the beginning of pre-season. Before the tests, they were familiarized with all experimental procedures. Squat jump (SJ), countermovement jump (CMJ), sprint (10 m/20 m), maximum dynamic strength (1RM), and Yo-Yo intermittent recovery tests level 1 were performed in three non-consecutive sessions. No significant differences were found between the categories for sprint times. The PRO players presented higher outcomes in the 1RM, SJ, CMJ, and Yo-Yo tests than the U-20 and U-17 players (P≤0.05). No significant differences were found between the U-20 and U-17 players in 1RM, and SJ/CMJ heights. The U-20 presented superior performance than the U-17 in the Yo-Yo test (P≤0.05). The findings indicated that PRO performed better than younger players in all assessments, except for the sprint tests. This may have been possible due to the differences in training experience, technical expertise and individual levels of strength/power. However, the absence of differences between the U-20 and U-17 groups highlighted the necessity of developing specific training strategies in order to improve the physical capacities of younger players, throughout the maturation process. Moreover, due to the importance of sprinting in soccer, it is strongly recommended that fitness coaches develop more effective strategies to improve speed ability in professional players.

Analysis of Injury Incidences in Male Professional Adult and Elite Youth Soccer Players: A Systematic Review

PubMed Central

Pfirrmann, Daniel; Herbst, Mark; Ingelfinger, Patrick; Simon, Perikles; Tug, Suzan

2016-01-01

Context:  The incidence of injury for elite youth and professional adult soccer players is an important concern, but the risk factors for these groups are different. Objective:  To summarize and compare the injury incidences and injury characteristics of male professional adult and elite youth soccer players. Data Sources:  We searched MEDLINE and Web of Science using the search terms elite, international, European, soccer, football, injury, injuries, epidemiology, incidence, prevalence, not female, not American football, and not rugby. We also used the search terms professional for studies on professional adult soccer players and high-level, soccer academy, youth, adolescent, and young for studies on elite youth soccer players. Study Selection:  Eligible studies were published in English, had a prospective cohort design, and had a minimum study period of 6 months. To ensure that injury data were assessed in relationship to the athlete's individual exposure, we included only studies that reported on injuries and documented exposure volume. Data Extraction:  Two independent reviewers applied the selection criteria and assessed the quality of the studies. Data Synthesis:  A total of 676 studies were retrieved from the literature search. Eighteen articles met the inclusion criteria: 6 for elite youth and 12 for professional adult soccer players. Conclusions:  Injury rates were higher for matches than for training for both youth and adult players. Youth players had a higher incidence of training injuries than professionals. Efforts must be made to reduce the overall injury rate in matches. Therefore, preventive interventions, such as adequately enforcing rules and focusing on fair play, must be analyzed and developed to reduce match-related injury incidences. Reducing training injuries should be a particular focus for youth soccer players. PMID:27244125

Effects of Six Weeks of Medicine Ball Training on Throwing Velocity, Throwing Precision, and Isokinetic Strength of Shoulder Rotators in Female Handball Players.

PubMed

Raeder, Christian; Fernandez-Fernandez, Jaime; Ferrauti, Alexander

2015-07-01

The aim of this study was to investigate the effects of 6 weeks of medicine ball training (MBT) on throwing velocity, throwing precision, and isokinetic strength of shoulder rotators in competitive female handball players. Twenty-eight players (mean ± SD; age: 20.8 ± 3.3 years, height: 170.5 ± 5.6 cm, body mass: 65.2 ± 8.0 kg) were randomly assigned to an MBT group (TG; n = 15) and a control group (CG; n = 13). TG performed a supervised MBT program, 3 times a week for a total of 6 weeks, focusing on handball-specific movement patterns. Both groups, TG and CG, also conducted a supervised shoulder injury prevention program with elastic tubes, as part of the warm-up, finishing with regular handball throws. Results showed a significant group × time interaction in throwing velocity (p < 0.001) with the TG posttest results being significantly higher compared with CG (d = 2.1), and also a significant main time effect (p < 0.001), with an increase in throwing velocity of 14% (d = 3.0) and 3.7% (d = 0.3) for both TG and CG, respectively. Throwing precision did not significantly differ between groups and time points. Isokinetic strength measures revealed a significant group × time interaction (p ≤ 0.05) with the TG posttest results being significantly higher compared with CG (d = 0.9) and also a significant main time effect (p < 0.01) with an increase of 15% (d = 0.9) in concentric shoulder internal rotation at 180°·s⁻¹ in the dominant arm in TG, whereas no significant changes occurred in CG. The present results indicate that 6 weeks of MBT elicit significant improvements in functional performance (i.e., throwing velocity) in female handball players, whereas throwing precision remained unaffected. Medicine ball training exercises seem to be a useful and inexpensive strength training strategy in enhancing functional performance by closely mimicking sport-specific movement activities.

Increased distance of shooting on basketball jump shot.

PubMed

Okazaki, Victor Hugo Alves; Rodacki, André Luiz Félix

2012-01-01

The present study analyzed the effect of increased distance on basketball jump shot outcome and performance. Ten male expert basketball players were filmed and a number of kinematic variables analyzed during jump shot that were performed from three conditions to represent close, intermediate and far distances (2.8, 4.6, and 6.4m, respectively). Shot accuracy decreased from 59% (close) to 37% (far), in function of the task constraints (p < 0.05). Ball release height decreased (p < 0.05) from 2.46 m (close) to 2.38m (intermediate) and to 2.33m (long). Release angle also decreased (p < 0.05) when shot was performed from close (78.92°) in comparison to intermediate distances (65.60°). While, ball release velocity increased (p < 0.05) from 4.39 m/s (close) to 5.75 m·s(-1) (intermediate) to 6.89 m·s(-1) (far). These changes in ball release height, angle and velocity, related to movement performance adaptations were suggested as the main factors that influence jump shot accuracy when distance is augmented. Key pointsThe increased distance leads to greater spatial con-straint over shot movement that demands an adapta-tion of the movement for the regulation of the accu-racy and the impulse generation to release the ball.The reduction in balls release height and release angle, in addition to the increase in balls release ve-locity, were suggested as the main factors that de-creased shot accuracy with the distance increased.Players should look for release angles of shooting that provide an optimal balls release velocity to im-prove accuracy.

Reported concussion incidence in youth community Rugby Union and parental assessment of post head injury cognitive recovery using the King-Devick test.

PubMed

Silver, David; Brown, Nicola; Gissane, Conor

2018-05-15

To assess the frequency of reported head injuries in youth community Rugby Union and determine whether the King-Devick (K-D) test could be used by parents as a means to chart cognitive recovery following head injury. A prospective cohort study of 489 junior players (U9-U18) conducted at a community level Rugby Union club over four seasons. All players undertook a baseline K-D test at the start of each season. Players identified with suspected concussion performed the K-D test post injury and results were compared to their most recent baseline assessment. Parent/Guardians of the player then oversaw repeated daily testing until baseline scores were surpassed. 49 players were sent for assessment after suspected head injury. 46 parents oversaw daily repeated K-D testing (93.8% engagement). The median reduction in K-D test performance speed post-injury from baseline was 7.32 s (IQR 2.46 - 7.98). A median of 5.1 days/tests were taken for players to surpass baseline performance. No correlation was found between initial post-injury test and cognitive recovery time. 38 head injuries were reported from match play with an incidence rate of 12.7 per 1000 match hours (95% CI 9.2-17.5). The K-D test is a practical tool for baseline, post injury and parentally supervised repeated testing within youth community Rugby Union. Incidence of reported head injuries following match play is higher than previously reported. Parental engagement was high. Post-Injury K-D test performance should not be used as a means to predict symptom recovery. Copyright © 2018 Elsevier B.V. All rights reserved.

Physique and Performance of Young Wheelchair Basketball Players in Relation with Classification

PubMed Central

Zancanaro, Carlo

2015-01-01

The relationships among physical characteristics, performance, and functional ability classification of younger wheelchair basketball players have been barely investigated to date. The purpose of this work was to assess anthropometry, body composition, and performance in sport-specific field tests in a national sample of Italian younger wheelchair basketball players as well as to evaluate the association of these variables with the players’ functional ability classification and game-related statistics. Several anthropometric measurements were obtained for 52 out of 91 eligible players nationwide. Performance was assessed in seven sport-specific field tests (5m sprint, 20m sprint with ball, suicide, maximal pass, pass for accuracy, spot shot and lay-ups) and game-related statistics (free-throw points scored per match, two- and three-point field-goals scored per match, and their sum). Association between variables, and predictivity was assessed by correlation and regression analysis, respectively. Players were grouped into four Classes of increasing functional ability (A-D). One-way ANOVA with Bonferroni’s correction for multiple comparisons was used to assess differences between Classes. Sitting height and functional ability Class especially correlated with performance outcomes, but wheelchair basketball experience and skinfolds did not. Game-related statistics and sport-specific field-test scores all showed significant correlation with each other. Upper arm circumference and/or maximal pass and lay-ups test scores were able to explain 42 to 59% of variance in game-related statistics (P<0.001). A clear difference in performance was only found for functional ability Class A and D. Conclusion: In younger wheelchair basketball players, sitting height positively contributes to performance. The maximal pass and lay-ups test should be carefully considered in younger wheelchair basketball training plans. Functional ability Class reflects to a limited extent the actual differences in performance. PMID:26606681

Comparison of tensiomyographic neuromuscular characteristics between muscles of the dominant and non-dominant lower extremity in male soccer players.

PubMed

Alvarez-Diaz, Pedro; Alentorn-Geli, Eduard; Ramon, Silvia; Marin, Miguel; Steinbacher, Gilbert; Rius, Marta; Seijas, Roberto; Ballester, Jordi; Cugat, Ramon

2016-07-01

Tensiomyography (TMG) has been used to assess neuromuscular characteristics of muscles of the lower extremity in soccer players. However, the effects of lower extremity dominance on TMG characteristics in this population have not been reported to date. The purpose of this study was to compare the TMG neuromuscular characteristics between the dominant and non-dominant lower extremity in male soccer players. Thirty-eight consecutive healthy male soccer players underwent resting TMG assessment of vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), semitendinosus (ST), biceps femoris (BF), gastrocnemius medialis (GM), and gastrocnemius lateralis (GL) in both lower extremities. The maximal displacement, delay time, contraction time, sustained time, and half-relaxation time were obtained and compared between both sides. There were no significant differences in the vast majority of the TMG parameters between both lower extremities. The dominant side demonstrated higher VM contraction time (p = 0.008), RF sustained time (p = 0.009), RF half-relaxation time (p = 0.01), and BF sustained time (p = 0.04), but lower VL contraction time (p = 0.03) and VL delay time (p = 0.02) compared to the non-dominant side. In general, TMG-assessed neuromuscular characteristics of the VM, VL, RF, ST, BF, GM, and GL were not affected by lower extremity dominance in male soccer players. Therefore, there is no need to assess both sides when using TMG to monitor the response to training or muscles at risk of injury in soccer players unless there is a specific reason. Prognostic study, Level II.

The usefulness and reliability of fitness testing protocols for ice hockey players: a literature review.

PubMed

Nightingale, Steven C; Miller, Stuart; Turner, Anthony

2013-06-01

Ice hockey, like most sports, uses fitness testing to assess athletes. This study reviews the current commonly used fitness testing protocols for ice hockey players, discussing their predictive values and reliability. It also discusses a range of less commonly used measures and limitations in current testing protocols. The article concludes with a proposed testing program suitable for ice hockey players.

Speech recovery and language plasticity can be facilitated by Sensori-Motor Fusion training in chronic non-fluent aphasia. A case report study.

PubMed

Haldin, Célise; Acher, Audrey; Kauffmann, Louise; Hueber, Thomas; Cousin, Emilie; Badin, Pierre; Perrier, Pascal; Fabre, Diandra; Perennou, Dominic; Detante, Olivier; Jaillard, Assia; Lœvenbruck, Hélène; Baciu, Monica

2017-11-17

The rehabilitation of speech disorders benefits from providing visual information which may improve speech motor plans in patients. We tested the proof of concept of a rehabilitation method (Sensori-Motor Fusion, SMF; Ultraspeech player) in one post-stroke patient presenting chronic non-fluent aphasia. SMF allows visualisation by the patient of target tongue and lips movements using high-speed ultrasound and video imaging. This can improve the patient's awareness of his/her own lingual and labial movements, which can, in turn, improve the representation of articulatory movements and increase the ability to coordinate and combine articulatory gestures. The auditory and oro-sensory feedback received by the patient as a result of his/her own pronunciation can be integrated with the target articulatory movements they watch. Thus, this method is founded on sensorimotor integration during speech. The SMF effect on this patient was assessed through qualitative comparison of language scores and quantitative analysis of acoustic parameters measured in a speech production task, before and after rehabilitation. We also investigated cerebral patterns of language reorganisation for rhyme detection and syllable repetition, to evaluate the influence of SMF on phonological-phonetic processes. Our results showed that SMF had a beneficial effect on this patient who qualitatively improved in naming, reading, word repetition and rhyme judgment tasks. Quantitative measurements of acoustic parameters indicate that the patient's production of vowels and syllables also improved. Compared with pre-SMF, the fMRI data in the post-SMF session revealed the activation of cerebral regions related to articulatory, auditory and somatosensory processes, which were expected to be recruited by SMF. We discuss neurocognitive and linguistic mechanisms which may explain speech improvement after SMF, as well as the advantages of using this speech rehabilitation method.

Identifying the processes underpinning anticipation and decision-making in a dynamic time-constrained task.

PubMed

Roca, André; Ford, Paul R; McRobert, Allistair P; Mark Williams, A

2011-08-01

A novel, representative task was used to examine skill-based differences in the perceptual and cognitive processes underlying performance on a dynamic, externally paced task. Skilled and less skilled soccer players were required to move and interact with life-size, action sequences involving 11 versus 11 soccer situations filmed from the perspective of a central defender in soccer. The ability of participants to anticipate the intentions of their opponents and to make decisions about how they should respond was measured across two separate experiments. In Experiment 1, visual search behaviors were examined using an eye-movement registration system. In Experiment 2, retrospective verbal reports of thinking were gathered from a new sample of skilled and less skilled participants. Skilled participants were more accurate than less skilled participants at anticipating the intentions of opponents and in deciding on an appropriate course of action. The skilled players employed a search strategy involving more fixations of shorter duration in a different sequential order and toward more disparate and informative locations in the display when compared with the less skilled counterparts. The skilled players generated a greater number of verbal report statements with a higher proportion of evaluation, prediction, and planning statements than the less skilled players, suggesting they employed more complex domain-specific memory representations to solve the task. Theoretical, methodological, and practical implications are discussed.

Muscle injuries of the lower extremity: a comparison between young and old male elite soccer players.

PubMed

Svensson, Kjell; Alricsson, Marie; Karnebäck, Gustav; Magounakis, Theo; Werner, Suzanne

2016-07-01

The aim of this study was to make a comparison between players in two age groups in an elite male soccer team regarding injury localisation within the muscle-tendon unit, injury size and muscle group in terms of muscle injuries of the lower extremity. Cohort study based on data collected from a Swedish elite male soccer team during the seasons 2007-2012. In total, 145 muscle injuries were included. Injury localisation to the tendon or muscle, the size of haematoma and the affected muscle group were assessed using ultrasound. Age comparison was made between younger players (≤23 years) and older players (>23 years). No difference regarding injury localisation to either the tendon or the muscle, or the size of haematoma between the two age groups was found. However, the older group of players suffered a significantly higher number of injuries to the triceps surae than the younger players (p = 0.012). In a Swedish team of male soccer players at elite level, there was no difference between players 23 years or younger and players older than 23 years, in terms of injury distribution to muscles or tendons. Players older than 23 years sustained more injuries to triceps surae when compared with players 23 years or younger. The clinical relevance is to pay attention to muscle function of triceps surae in older players and to screen those players who may need an injury prevention programme. II.

A Model for Comparing Game Theory and Artificial Intelligence Decision Making Processes

DTIC Science & Technology

1989-12-01

I V. Re-visions to PALANTIR Program .. .. .... .... .... ..... 20 4.1 Rewritten in the C Programming Lanigiiage...The PALANTIR , created by Capt Robert Palmer, had two uses: to train per- sonnel on the use of satellites and to provide insight into the movements...zero-sum game theory approach to reach decisions (11:23). This approach is discussed further in Chapter 2. 2 Although PALANTIR used game theory players

Who Networks? The Social Psychology of Virtual Communities

DTIC Science & Technology

2004-06-01

virtual life: the open side - characterized by communities of interest, civil society movements, virtual “states,” and 4 online gaming communities...network of people hailing from Sicily. Sometimes the offline/ online similari- ties mesh even more, as when a gaming society in a small Swedish town...Commercially owned and regulated graphics-based Massively Multi- Player Gaming Communities (EverQuest, The Matrix Online ®, etc.) • UseNET

A Weighted Kappa Coefficient for Three Observers as a Measure for Reliability of Expert Ratings on Characteristics in Handball Throwing Patterns

ERIC Educational Resources Information Center

Schorer, Jorg; Weiss, Christel

2007-01-01

Many methods for the identification of key variables in movement patterns have the problem that direct transferability back to coaches or players is not easy; this is because the variables used are not presented in the language of most sport participants. Using a research strategy--from the coaches back to the coaches--proposed by Roth (1996),…

The effect of ankle bracing on knee kinetics and kinematics during volleyball-specific tasks.

PubMed

West, T; Ng, L; Campbell, A

2014-12-01

The purpose of this study was to examine the effects of ankle bracing on knee kinetics and kinematics during volleyball tasks. Fifteen healthy, elite, female volleyball players performed a series of straight-line and lateral volleyball tasks with no brace and when wearing an ankle brace. A 14-camera Vicon motion analysis system and AMTI force plate were used to capture the kinetic and kinematic data. Knee range of motion, peak knee anterior-posterior and medial-lateral shear forces, and peak ground reaction forces that occurred between initial contact with the force plate and toe off were compared using paired sample t-tests between the braced and non-braced conditions (P < 0.05). The results revealed no significant effect of bracing on knee kinematics or ground reaction forces during any task or on knee kinetics during the straight-line movement volleyball tasks. However, ankle bracing was demonstrated to reduce knee lateral shear forces during all of the lateral movement volleyball tasks. Wearing the Active Ankle T2 brace will not impact knee joint range of motion and may in fact reduce shear loading to the knee joint in volleyball players. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of forefoot bending stiffness of badminton shoes on agility, comfort perception and lower leg kinematics during typical badminton movements.

PubMed

Park, Sang-Kyoon; Lam, Wing-Kai; Yoon, Sukhoon; Lee, Ki-Kwang; Ryu, Jiseon

2017-09-01

This study investigated whether an increase in the forefoot bending stiffness of a badminton shoe would positively affect agility, comfort and biomechanical variables during badminton-specific movements. Three shoe conditions with identical shoe upper and sole designs with different bending stiffness (Flexible, Regular and Stiff) were used. Elite male badminton players completed an agility test on a standard badminton court involving consecutive lunges in six directions, a comfort test performed by a pair of participants conducting a game-like practice trial and a biomechanics test involving a random assignment of consecutive right forward lunges. No significant differences were found in agility time and biomechanical variables among the three shoes. The players wearing the shoe with a flexible forefoot outsole demonstrated a decreased perception of comfort in the forefoot cushion compared to regular and stiffer conditions during the comfort test (p < 0.05). The results suggested that the modification of forefoot bending stiffness would influence individual perception of comfort but would not influence performance and lower extremity kinematics during the tested badminton-specific tasks. It was concluded that an optimisation of forefoot structure and materials in badminton shoes should consider the individual's perception to maximise footwear comfort in performance.

Cavum Septum Pellucidum in Retired American Pro-Football Players.

PubMed

Gardner, Raquel C; Hess, Christopher P; Brus-Ramer, Marcel; Possin, Katherine L; Cohn-Sheehy, Brendan I; Kramer, Joel H; Berger, Mitchel S; Yaffe, Kristine; Miller, Bruce; Rabinovici, Gil D

2016-01-01

Previous studies report that cavum septum pellucidum (CSP) is frequent among athletes with a history of repeated traumatic brain injury (TBI), such as boxers. Few studies of CSP in athletes, however, have assessed detailed features of the septum pellucidum in a case-control fashion. This is important because prevalence of CSP in the general population varies widely (2% to 85%) between studies. Further, rates of CSP among American pro-football players have not been described previously. We sought to characterize MRI features of the septum pellucidum in a series of retired pro-football players with a history of repeated concussive/subconcussive head traumas compared with controls. We retrospectively assessed retired American pro-football players presenting to our memory clinic with cognitive/behavioral symptoms in whom structural MRI was available with slice thickness ≤2 mm (n=17). Each player was matched to a memory clinic control patient with no history of TBI. Scans were interpreted by raters blinded to clinical information and TBI/football history, who measured CSP grade (0-absent, 1-equivocal, 2-mild, 3-moderate, 4-severe) and length according to a standard protocol. Sixteen of 17 (94%) players had a CSP graded ≥2 compared with 3 of 17 (18%) controls. CSP was significantly higher grade (p<0.001) and longer in players than controls (mean length±standard deviation: 10.6 mm±5.4 vs. 1.1 mm±1.3, p<0.001). Among patients presenting to a memory clinic, long high-grade CSP was more frequent in retired pro-football players compared with patients without a history of TBI.

Assessing Cognitive Performance in Badminton Players: A Reproducibility and Validity Study.

PubMed

van de Water, Tanja; Huijgen, Barbara; Faber, Irene; Elferink-Gemser, Marije

2017-01-01

Fast reaction and good inhibitory control are associated with elite sports performance. To evaluate the reproducibility and validity of a newly developed Badminton Reaction Inhibition Test (BRIT), fifteen elite (25 ± 4 years) and nine non-elite (24 ± 4 years) Dutch male badminton players participated in the study. The BRIT measured four components: domain-general reaction time, badminton-specific reaction time, domain-general inhibitory control and badminton-specific inhibitory control. Five participants were retested within three weeks on the badminton-specific components. Reproducibility was acceptable for badminton-specific reaction time (ICC = 0.626, CV = 6%) and for badminton-specific inhibitory control (ICC = 0.317, CV = 13%). Good construct validity was shown for badminton-specific reaction time discriminating between elite and non-elite players (F = 6.650, p < 0.05). Elite players did not outscore non-elite players on domain-general reaction time nor on both components of inhibitory control (p > 0.05). Concurrent validity for domain-general reaction time was good, as it was associated with a national ranking for elite (p = 0.70, p < 0.01) and non-elite (p = 0.70, p < 0.05) players. No relationship was found between the national ranking and badminton-specific reaction time, nor both components of inhibitory control (p > 0.05). In conclusion, reproducibility and validity of inhibitory control assessment was not confirmed, however, the BRIT appears a reproducible and valid measure of reaction time in badminton players. Reaction time measured with the BRIT may provide input for training programs aiming to improve badminton players' performance.

Encouraging junior community netball players to learn correct safe landing technique.

PubMed

White, Peta E; Ullah, Shahid; Donaldson, Alex; Otago, Leonie; Saunders, Natalie; Romiti, Maria; Finch, Caroline F

2012-01-01

Behavioural factors and beliefs are important determinants of the adoption of sports injury interventions. This study aimed to understand behavioural factors associated with junior community netball players' intentions to learn correct landing technique during coach-led training sessions, proposed as a means of reducing their risk of lower limb injury. Cross-sectional survey. 287 female players from 58 junior netball teams in the 2007/2008-summer competition completed a 13-item questionnaire developed from the Theory of Planned Behaviour (TPB). This assessed players' attitudes (four items), subjective norms (four), perceived behavioural control (four) and intentions (one) around the safety behaviour of learning correct landing technique at netball training. All items were rated on a seven-point bipolar scale. Cluster-adjusted logistic regression was used to assess which TPB constructs were most associated with strong intentions. Players had positive intentions and attitudes towards learning safe landing technique and perceived positive social pressure from significant others. They also perceived themselves to have considerable control over engaging (or not) in this behaviour. Players' attitudes (p<0.001) and subjective norms (p<0.001), but not perceived behavioural control (p=0.49), were associated with strong intentions to learn correct landing technique at training. Injury prevention implementation strategies aimed at maximising junior players' participation in correct landing training programs should emphasise the benefits of learning correct landing technique (i.e. change attitudes) and involve significant others and role models whom junior players admire (i.e. capitalise on social norms) in the promotion of such programs. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Australian Football League concussion guidelines: what do community players think?

PubMed Central

White, Peta E; Donaldson, Alex; Sullivan, S John; Newton, Joshua

2016-01-01

Background Preventing concussion in sport is a global challenge. To assess community-level adult male Australian Football players’ views on following the Australian Football League's (AFL) concussion guidelines. Methods 3 focus groups, each comprising 6 players from 1 regional league, were conducted until saturation of issues raised. Discussions followed a semistructured script and were audio-recorded and transcribed verbatim. Thematic analysis was conducted by 2 coders independently. Results Identified advantages of the guidelines included highlighting the seriousness of concussion; changing the culture around playing with concussion and shifting return-to-play decision responsibility from players to others. Disadvantages included players being removed from play unnecessarily; removal of players’ rights to decide if they are fit to play and players changing their behaviours to avoid being removed from play. Identified facilitators to guideline use included local league enforcement; broad information dissemination and impartial medically trained staff to assess concussion. Identified barriers to guideline use included players’ desire to play at all costs; external pressure that encouraged players to return to play prematurely; and inconvenience and cost. Conclusions Players generally understand that the AFL concussion guidelines protect their long-term welfare. However, their desire to play at all costs and help their team win is a common barrier to reporting concussion and adhering to guidelines. Leagues should take a lead role by mandating and enforcing the use of the guidelines and educating coaches, game day medical providers and players. The return-to-play component of the guidelines is complex and needs further consideration in the context of community sport. PMID:28890801

Would you like to play together? Adults' attachment and the mirror game.

PubMed

Feniger-Schaal, Rinat; Noy, Lior; Hart, Yuval; Koren-Karie, Nina; Mayo, Avraham E; Alon, Uri

2016-01-01

Why is it easy for some people to play together and difficult for others? In this interdisciplinary pilot study, we looked at dyadic interaction in motion as a paradigm to explore the expression of attachment in adulthood. We used a device that gives simple, quantitative and automated indicators for the quality of interaction while playing the mirror game. Forty-seven participants played the mirror game with the same gender-matched expert players. In addition, participants were interviewed on the Adult Attachment Interview to assess their quality of attachment. Using high resolution kinematic measures, we found that secure attachment was correlated with high complexity of the game and low synchrony compared to insecure attachment. The findings suggest that security of attachment is related to a more exploratory and less rigid game than insecure-dismissing attachment. These preliminary findings imply that high resolution analysis of simple movement interaction could carry information about attachment behavior.

Neuroimaging of cognitive dysfunction and depression in aging retired National Football League players: a cross-sectional study.

PubMed

Hart, John; Kraut, Michael A; Womack, Kyle B; Strain, Jeremy; Didehbani, Nyaz; Bartz, Elizabeth; Conover, Heather; Mansinghani, Sethesh; Lu, Hanzhang; Cullum, C Munro

2013-03-01

OBJECTIVES To assess cognitive impairment and depression in aging former professional football (National Football League [NFL]) players and to identify neuroimaging correlates of these dysfunctions. DESIGN We compared former NFL players with cognitive impairment and depression, cognitively normal retired players who were not depressed, and matched healthy control subjects. SETTING Research center in the North Texas region of the United States. PATIENTS Cross-sectional sample of former NFL players with and without a history of concussion recruited from the North Texas region and age-, education-, and IQ-matched controls. Thirty-four retired NFL players (mean age, 61.8 years) underwent neurological and neuropsychological assessment. A subset of 26 players also underwent detailed neuroimaging; imaging data in this subset were compared with imaging data acquired in 26 healthy matched controls. MAIN OUTCOME MEASURES Neuropsychological measures, clinical diagnoses of depression, neuroimaging mea-sures of white matter pathology, and a measure of cerebral blood flow. RESULTS Of the 34 former NFL players, 20 were cognitively normal. Four were diagnosed as having a fixed cognitive deficit; 8, mild cognitive impairment; 2, dementia; and 8, depression. Of the subgroup in whom neuroimaging data were acquired, cognitively impaired participants showed the greatest deficits on tests of naming, word finding, and visual/verbal episodic memory. We found significant differences in white matter abnormalities in cognitively impaired and depressed retired players compared with their respective controls. Regional blood flow differences in the cognitively impaired group (left temporal pole, inferior parietal lobule, and superior temporal gyrus) corresponded to regions associated with impaired neurocognitive performance (problems with memory, naming, and word finding). CONCLUSIONS Cognitive deficits and depression appear to be more common in aging former NFL players compared with healthy controls. These deficits are correlated with white matter abnormalities and changes in regional cerebral blood flow.

Kinanthropometric and performance characteristics of elite and non-elite female softball players.

PubMed

Singh, S; Singh, M; Rathi, B

2013-12-01

The purpose of the present study was to compare the kinanthropometric and performance characteristics of elite and non-elite female softball players. A total forty elite and non-elite level female softball players were selected from the different colleges affiliated to the Guru Nanak Dev University, Amritsar, for the present study. The height of subjects was measured by using the standard anthropometric rod. Weight was measured with portable weighing machine. Widths and diameters of body parts were measured by using digital caliper. Girths and lengths were taken with steel tape. Skinfold thickness measurements were taken using the Slimguide skinfold caliper. All subjects were also assessed for performance tests i.e. vertical jump, 50m sprint, medicine ball throw, 10×4m shuttle run and reaction time. Independent samples t-test reveals that elite female softball players were significantly taller (P<0.05) than the non- elite players. The elite female softball players also had significantly greater biacromial (P<0.05), bi- illiocristal (P<0.05) and bicondylar femur (P<0.05) diameters and forearm circumference (P<0.05) as compared to non-elite female softball players. The non-elite female softball players were found to have significantly greater thigh circumference (P<0.05), triceps (P<0.05) and subscapular (P<0.05) skinfold thicknesses than the elite female softball players. The non-elite players were also found to have significantly higher percentage body fat (P<0.05) than the elite players. In performance tests, the elite players were found to have significantly better reaction time (P<0.05), speed (P<0.05) and agility (P<0.05) as compared to non-elite female softball players. The elite female softball players had significantly greater kinanthropometric characteristics, body composition and performance characteristics than the non-elite female softball players.

Kicking Performance in Young U9 to U20 Soccer Players: Assessment of Velocity and Accuracy Simultaneously

ERIC Educational Resources Information Center

Vieira, Luiz H. P.; Cunha, Sérgio A.; Moraes, Renato; Barbieri, Fabio A.; Aquino, Rodrigo; Oliveira, Lucas de P.; Navarro, Martina; Bedo, Bruno L. S.; Santiago, Paulo R. P.

2018-01-01

Purpose: The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. Method: Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to measure (300 Hz) ball velocity (V[subscript ball]), foot velocity (V[subscript foot]),…

A Model for Predicting Cognitive and Emotional Health from Structural and Functional Neurocircuitry Following Traumatic Brain Injury

DTIC Science & Technology

2016-10-01

players : the NCAA Concussion Study . JAMA, 2003. 290(19): p. 2556-63. 3. Bogdanova, Y. and M. Verfaellie, Cognitive sequelae of blast-induced traumatic...football players : the NCAA concussion study , JAMA 290 (2003) 2556–2563. [22] L.C. Morey, Personality Assessment Inventory, Psychological Assessment...assessment. This study will address this problem by collecting measures of white matter integrity and concomitant neuropsychological status at five time points

The effect of a novel movement strategy in decreasing ACL risk factors in female adolescent soccer players

PubMed Central

Celebrini, Richard G.; Eng, Janice J.; Miller, William C.; Ekegren, Christina L.; Johnston, James D.; MacIntyre, Donna L.

2015-01-01

There is a need to investigate the effect of specific movement strategies in reducing biomechanical risk factors for ACL injury in young female athletes. The purpose of this study was 1) to determine the feasibility of implementing a novel movement strategy (Core-PAC) into a team warm-up prior to soccer training based on subject compliance and integration of the Core-PAC into the warm-up and 2) to determine whether the Core-PAC would improve peak knee flexion angles and peak abduction moments at the knee during a side-cut (SC) and an unanticipated side-cut (USC) prior to kicking a soccer ball, and a side-hop (SH) task after immediate instruction and after a four-week training program. A convenience sample of ten 14–16 year old female soccer players were instructed in the Core-PAC immediately after baseline testing and during a training program consisting of a 20-minute warm-up, two-times per week. The Core-PAC was understood and accepted by the subjects and incorporated into their warm-up activities with good compliance. After the immediate instruction, there were significant increases in peak knee flexion angles of a mean 6.4° during the SC (p = 0.001), 3.5° during the USC (p = 0.007), and 5.8° during the SH (p < 0.001) tasks. Peak knee abduction moments decreased by a mean of 0.25 Nm/kg during the SC (p < 0.03), 0.17 Nm/kg during the USC (p = 0.05), and 0.27 Nm/kg during the SH (p = 0.04) tasks. After the 4-week training program, some individuals showed improvement. The results of this study suggest that the Core-PAC may be one method of modifying high-risk movements for ACL injury such as side-cutting and single-leg landing. PMID:22210470

Dynamic knee stability and ballistic knee movement after ACL reconstruction: an application on instep soccer kick.

PubMed

Cordeiro, Nuno; Cortes, Nelson; Fernandes, Orlando; Diniz, Ana; Pezarat-Correia, Pedro

2015-04-01

The instep soccer kick is a pre-programmed ballistic movement with a typical agonist-antagonist coordination pattern. The coordination pattern of the kick can provide insight into deficient neuromuscular control. The purpose of this study was to investigate knee kinematics and hamstrings/quadriceps coordination pattern during the knee ballistic extension phase of the instep kick in soccer players after anterior cruciate ligament reconstruction (ACL reconstruction). Seventeen players from the Portuguese Soccer League participated in this study. Eight ACL-reconstructed athletes (experimental group) and 9 healthy individuals (control group) performed three instep kicks. Knee kinematics (flexion and extension angles at football contact and maximum velocity instants) were calculated during the kicks. Rectus femoris (RF), vastus lateralis, vastus medialis, biceps femoralis, and semitendinosus muscle activations were quantified during the knee extension phase. The ACL-reconstructed group had significantly lower knee extension angle (-1.2 ± 1.6, p < 0.021) and increased variability (1.1 ± 1.2, p < 0.012) when compared with the control group. Within the EMG variables, the RF had a significantly greater activity in the ACL-reconstructed group than in the control group (79.9 ± 27.7 % MVC vs. 49.2 ± 20.8 % MVC, respectively, p < 0.034). No other statistically significant differences were found. The findings of this study demonstrate that changes in ACL-reconstructed individuals were observed on knee extension angle and RF muscle activation while performing an instep kick. These findings are in accordance with the knee stability recovery process after ACL reconstruction. No differences were observed in the ballistic control movement pattern between normal and ACL-reconstructed subjects. Performing open kinetic chain exercises using ballistic movements can be beneficial when recovering from ACL reconstruction. The exercises should focus on achieving multi-joint coordination and full knee extension (range of motion). III.

Relationship between achievement goal orientations and the perceived purposes of playing rugby union for professional and amateur players.

PubMed

Treasure, D C; Carpenter, P J; Power, K T

2000-08-01

The recent professionalization of rugby union makes it an excellent achievement context in which to examine the relationship between achievement goal orientations and the perceived purposes of sport as a function of competitive standard. During the 1996-97 season, 73 professional and 106 amateur rugby players in England completed a series of questionnaires assessing their achievement goal orientations, beliefs about the purposes of rugby and demographic information. The results of a canonical correlation analysis revealed a conceptually coherent relationship between achievement goal orientations and purposes of rugby. Specifically, a high ego/moderate task orientation was positively related to fitness, aggression and financial remuneration as significant purposes of rugby. Professional players scored higher on those purposes of rugby related to aggression, financial remuneration and fitness, but lower on sportspersonship than amateur players. Professional players also reported higher task and ego goal orientations than amateur players. The findings are discussed in terms of the differences in lifestyle and motivation of professional and amateur rugby union players.

Locomotor performance in highly-trained young soccer players: does body size always matter?

PubMed

Buchheit, M; Mendez-Villanueva, A; Mayer, N; Jullien, H; Marles, A; Bosquet, L; Maille, P; Morin, J-B; Cazorla, G; Lambert, P

2014-06-01

To examine the effects of body size on locomotor performance, 807 15-year-old French and 64 Qatari soccer players participated in the present study. They performed a 40-m sprint and an incremental running test to assess maximal sprinting (MSS) and aerobic speeds, respectively. French players were advanced in maturity, taller, heavier, faster and fitter than their Qatari counterparts (e.g., Cohen's d=+1.3 and + 0.5 for body mass and MSS). However, when adjusted for body mass (BM), Qatari players had possibly greater MSS than French players (d=+0.2). A relative age effect was observed within both countries, with the players born in the first quarter of the year being taller, heavier and faster that those born during the fourth quarter (e.g., d=+0.2 for MSS in French players). When directly adjusted for BM, these MSS differences remained (d=+0.2). Finally, in both countries, players selected in National teams were taller, heavier, faster and fitter than their non-selected counterparts (e.g., d=+0.6 for MSS in French players), even after adjustments for body size (d=+0.5). Differences in locomotor performances between players with different phenotypes are likely mediated by differences in body size. However, when considering more homogeneous player groups, body dimensions are unlikely to substantially explain the superior locomotor performances of older and/or international players. © Georg Thieme Verlag KG Stuttgart · New York.

Longitudinal development of match-running performance in elite male youth soccer players.

PubMed

Saward, C; Morris, J G; Nevill, M E; Nevill, A M; Sunderland, C

2016-08-01

This study longitudinally examined age-related changes in the match-running performance of retained and released elite youth soccer players aged 8-18 years. The effect of playing position on age-related changes was also considered. Across three seasons, 263 elite youth soccer players were assessed in 1-29 competitive matches (988 player-matches). For each player-match, total distance and distances covered at age group-specific speed zones (low-speed, high-speed, sprinting) were calculated using 1 Hz or 5 Hz GPS. Mixed modeling predicted that match-running performance developed nonlinearly, with age-related changes best described with quadratic age terms. Modeling predicted that playing position significantly modified age-related changes (P < 0.05) and retained players covered significantly more low-speed distance compared with released players (P < 0.05), by 75 ± 71 m/h (mean ± 95% CI; effect size ± 95% CI: 0.35 ± 0.34). Model intercepts randomly varied, indicating differences between players in match-running performance unexplained by age, playing position or status. These findings may assist experts in developing training programs specific to the match play demands of players of different ages and playing positions. Although retained players covered more low-speed distance than released players, further study of the actions comprising low-speed distance during match play is warranted to better understand factors differentiating retained and released players. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Assessing Video Games to Improve Driving Skills: A Literature Review and Observational Study

PubMed Central

Sue, Damian; Vichitvanichphong, Suchada

2014-01-01

Background For individuals, especially older adults, playing video games is a promising tool for improving their driving skills. The ease of use, wide availability, and interactivity of gaming consoles make them an attractive simulation tool. Objective The objective of this study was to look at the feasibility and effects of installing video game consoles in the homes of individuals looking to improve their driving skills. Methods A systematic literature review was conducted to assess the effect of playing video games on improving driving skills. An observatory study was performed to evaluate the feasibility of using an Xbox 360 Kinect console for improving driving skills. Results Twenty–nine articles, which discuss the implementation of video games in improving driving skills were found in literature. On our study, it was found the Xbox 360 with Kinect is capable of improving physical and mental activities. Xbox Video games were introduced to engage players in physical, visual and cognitive activities including endurance, postural sway, reaction time, eyesight, eye movement, attention and concentration, difficulties with orientation, and semantic fluency. However, manual dexterity, visuo-spatial perception and binocular vision could not be addressed by these games. It was observed that Xbox Kinect (by incorporating Kinect sensor facilities) combines physical, visual and cognitive engagement of players. These results were consistent with those from the literature review. Conclusions From the research that has been carried out, we can conclude that video game consoles are a viable solution for improving user’s physical and mental state. In future we propose to carry a thorough evaluation of the effects of video games on driving skills in elderly people. PMID:25654355

Risk assessment in professional football: an examination of accidents and incidents in the 1994 World Cup finals.

PubMed Central

Hawkins, R D; Fuller, C W

1996-01-01

OBJECTIVE: To assess the risks to footballers' health and safety during competitive international matches, with identification of the most common causes of injury. METHODS: Videos of 44 of the 52 matches played during the 1994 World Cup finals staged in the USA were analysed. During each match, several relevant variables were recorded, including the number of fouls, injuries, treatments, times of incidents, identity of players treated or injured, and the injury mechanism. Additional information on players' injuries was obtained from the extensive media coverage of the event. RESULTS: Only 29% of injuries resulted from foul play, whereas 71% of injuries to players occurred where no foul play was adjudged by the referee to have taken place (P < 0.01). Defenders were found to be proportionately subjected to a greater risk of injury than other players (P < 0.05). Fifteen per cent of all injuries were judged to be at least moderate, resulting in the player missing at least one match. Frequency of moderate injury was 1026 injuries per 100,000 hours played. CONCLUSIONS: The major causes of injuries during international football matches were not found to be associated with foul play, as judged by the referees. However, in those cases where injuries occurred without a foul being committed, almost 50% involved player to player contact. This gives some cause for concern and is worth further investigation. Images Figure 2 PMID:8799605

Does well maintained graft provide consistent return to play after medial ulnar collateral ligament reconstruction of the elbow joint in elite baseball players?

PubMed

Park, Jin-Young; Oh, Kyung-Soo; Bahng, Seung-Chul; Chung, Seok-Won; Choi, Jin-Ho

2014-06-01

Several studies have reported the clinical outcomes of medial ulnar collateral ligament (MUCL) reconstruction of the elbow joint in throwing athletes, including the rate of return to sports. However, little has been known about the imaging outcomes after MUCL reconstruction. The aim of this study is to report the clinical and imaging outcomes after MUCL reconstruction using figure of eight fashion in the elite and professional baseball players. This study included 17 baseball players, who underwent MUCL reconstruction between July 2007 and May 2010. The average follow-up period was 48.6 months. Imaging assessment consisted of preoperative plain and stress radiographs, magnetic resonance imaging, and postoperative serial ultrasonography. The clinical assessments were composed of visual analogue scale (VAS) for pain, range of motion, and the Conway scale. The mean VAS score was 6.4 (range, 3 to 8) preoperatively and 2.2 (range, 0 to 4) postoperatively (p < 0.05). There were nine players (53%) classified as excellent who returned to sports at the same or higher level compared to preinjury. Serial ultrasonography revealed well-maintained grafts at 3 and 12 months in all of the players. Five out of 17 players showed decreased echogenecity in the common flexor tendon at 3 months, which was considered as remaining tissue swelling and resolved completely at 12 months. All grafts are well-maintained until 12-months based on the ultrasonographic findings, although only 53% of the players returned to preinjury level.

Shoulder pain among high-level volleyball players and preseason features.

PubMed

Forthomme, Benedicte; Wieczorek, Valerie; Frisch, Anne; Crielaard, Jean-Michel; Croisier, Jean-Louis

2013-10-01

The main goal of this prospective study was to identify the most significant intrinsic risk factors for shoulder pain by measuring strength developed by shoulder rotators and by carrying out various morphostatic assessments. Sixty-six players (mean ± SD age = 24 ± 5 yr) were recruited from nine volleyball teams from the first and second divisions (34 men and 32 women) to participate in the study. Before the start of the volleyball season, all the participants completed a preseason questionnaire and underwent both a bilateral isokinetic evaluation of the shoulders and morphostatic measurements. During the subsequent 6 months of the competition period, the players reported through a weekly questionnaire any shoulder pain experienced. During the ongoing season, 23% (15 of 66 players) of the volleyball players experienced dominant shoulder pain. Interestingly, participants who reported a history of dominant shoulder pain were found to have nine times higher risk of suffering further pain in their dominant shoulder. The eccentric maximal strength developed by the internal and external rotators was found to represent a protective factor in the volleyball players (respective odds ratios = 0.946, P = 0.01 and 0.94, P = 0.05). No risk factors were found among the shoulder morphostatic measurements. In our study, the evaluation of shoulder rotator muscle strength through isokinetic assessment, especially eccentric mode, appeared to be the most contributing parameter to identify risk factors for shoulder pain. This evaluation should allow to better identify players at risk.

Offensive tactical thinking level of wheelchair basketball players in Arab countries.

PubMed

Hindawi, Omar S; Orabi, Samira; Al Arjan, Jafar; Judge, Lawrence W; Cottingham, Michael; Bellar, David Michael

2013-01-01

The purpose of this study was to assess the appropriateness of offensive tactical decision-making of Arab basketball players, and to determine if there are differences in the appropriateness of offensive tactical decision-making within the various disability classifications of Arab basketball players. A twenty-question survey was formulated to assess decision-making in offensive tactical situations in wheelchair basketball players. Participants in the present study were 108 athletes from 10 Arab national teams participating in wheelchair basketball. The mean offensive tactical thinking level of wheelchair basketball players in the 20 different situations in the Arab countries ranged between 1.38-2.84, and the standard deviations for these 20 means ranged from 0.41 to 0.90. The total mean of all tactical situations was 2.33, which is moderate thinking level. The influence of the disability classification on the offensive tactical thinking of wheelchair basketball players was addressed by examining the data via a one-way ANOVA. The ANOVA revealed no significant differences among disability classifications/categories in tactical thinking (F(3, 104)=1.12, p=0.34). This study represents the first attempt to identify why Arab nations have not consistently qualified for the Paralympics or World Championships. These findings indicate that the moderate offensive tactical thinking level of wheelchair basketball players on Arab national teams may be part of the reason that performances of these teams have not been as strong as they would like.

The assessment of airway maneuvers and interventions in university Canadian football, ice hockey, and soccer players.

PubMed

Delaney, J Scott; Al-Kashmiri, Ammar; Baylis, Penny-Jane; Troutman, Tracy; Aljufaili, Mahmood; Correa, José A

2011-01-01

Managing an airway in an unconscious athlete is a lifesaving skill that may be made more difficult by the recent changes in protective equipment. Different airway maneuvers and techniques may be required to help ventilate an unconscious athlete who is wearing full protective equipment. To assess the effectiveness of different airway maneuvers with football, ice hockey, and soccer players wearing full protective equipment. Crossover study. University sports medicine clinic. A total of 146 university varsity athletes, consisting of 62 football, 45 ice hockey, and 39 soccer players. Athletes were assessed for different airway and physical characteristics. Three investigators then evaluated the effectiveness of different bag-valve-mask (BVM) ventilation techniques in supine athletes who were wearing protective equipment while inline cervical spine immobilization was maintained. The effectiveness of 1-person BVM ventilation (1-BVM), 2-person BVM ventilation (2-BVM), and inline immobilization and ventilation (IIV) was judged by each investigator for each athlete using a 4-point rating scale. All forms of ventilation were least difficult in soccer players and most difficult in football players. When compared with 1-BVM, both 2-BVM and IIV were deemed more effective by all investigators for all athletes. Interference from the helmet and stabilizer were common reasons for difficult ventilation in football and ice hockey players. Sports medicine professionals should practice and be comfortable with different ventilation techniques for athletes wearing full equipment. The use of a new ventilation technique, termed inline immobilization and ventilation, may be beneficial, especially when the number of responders is limited.

The Importance of Parents' Behavior in their Children's Enjoyment and Amotivation in Sports.

PubMed

Sánchez-Miguel, Pedro A; Leo, Francisco M; Sánchez-Oliva, David; Amado, Diana; García-Calvo, Tomás

2013-03-01

The main aim of the research was to examine the relationship between motivational orientations and parents' behavior with regard to the players' motivational orientation, motivational climate, enjoyment and amotivation. The sample comprised 723 athletes (M = 12.37, SD = 1.48) and 723 parents (M = 46.46, SD = 2.56). Players were male and female who belonged to federative basketball, handball, football and volleyball teams. Parents and athletes completed questionnaires that assessed motivational orientations, parents' involvement in the practice as well as enjoyment and motivation in the sport. Results showed a positive relationship between parents' support of the sport and players' enjoyment and a negative relationship with players' amotivation. Moreover, in players who perceived more pressure from their parents, there was a positive association with amotivation and a negative one with enjoyment. Lastly, it was emphasized that appropriate parental participation can promote an increase of players' enjoyment of and motivation for sport.

Does shoe heel design influence ground reaction forces and knee moments during maximum lunges in elite and intermediate badminton players?

PubMed

Lam, Wing-Kai; Ryue, Jaejin; Lee, Ki-Kwang; Park, Sang-Kyoon; Cheung, Jason Tak-Man; Ryu, Jiseon

2017-01-01

Lunge is one frequently executed movement in badminton and involves a unique sagittal footstrike angle of more than 40 degrees at initial ground contact compared with other manoeuvres. This study examined if the shoe heel curvature design of a badminton shoe would influence shoe-ground kinematics, ground reaction forces, and knee moments during lunge. Eleven elite and fifteen intermediate players performed five left-forward maximum lunge trials with Rounded Heel Shoe (RHS), Flattened Heel Shoe (FHS), and Standard Heel Shoes (SHS). Shoe-ground kinematics, ground reaction forces, and knee moments were measured by using synchronized force platform and motion analysis system. A 2 (Group) x 3 (Shoe) ANOVA with repeated measures was performed to determine the effects of different shoes and different playing levels, as well as the interaction of two factors on all variables. Shoe effect indicated that players demonstrated lower maximum vertical loading rate in RHS than the other two shoes (P < 0.05). Group effect revealed that elite players exhibited larger footstrike angle, faster approaching speed, lower peak horizontal force and horizontal loading rates but higher vertical loading rates and larger peak knee flexion and extension moments (P < 0.05). Analysis of Interactions of Group x Shoe for maximum and mean vertical loading rates (P < 0.05) indicated that elite players exhibited lower left maximum and mean vertical loading rates in RHS compared to FHS (P < 0.01), while the intermediate group did not show any Shoe effect on vertical loading rates. These findings indicate that shoe heel curvature would play some role in altering ground reaction force impact during badminton lunge. The differences in impact loads and knee moments between elite and intermediate players may be useful in optimizing footwear design and training strategy to minimize the potential risks for impact related injuries in badminton.

Variability of Metabolic Power Data in Elite Soccer Players During Pre-Season Matches

PubMed Central

Hoppe, Matthias Wilhelm; Baumgart, Christian; Slomka, Mirko; Polglaze, Ted; Freiwald, Jürgen

2017-01-01

Abstract This study aimed to determine the within-subject variability of GPS-derived metabolic power data in elite soccer players across several pre-season matches and compare the variability of high metabolic power, velocity, acceleration and deceleration running. Additionally, differences in metabolic power data among playing positions and relationships with various physical abilities were also investigated. Metabolic power data from 12 outfield starting players competing in the German Bundesliga were collected during five pre-season matches using GPS-technology (10 Hz). The players were also tested for speed, agility, power and intermittent endurance. Variability of global metabolic power data such as energy expenditure (CV = 2.2-7.0%) was lower than that for high-intensity including time ≥20 W·kg-1 (CV = 14.0-26.2%). Variability of high metabolic power (≥20 W·kg-1; CV = 14.1 ± 3.5%) was comparable to that of high velocity (≥15.5 km·h-1; CV = 17.0 ± 6.2%), acceleration (≥3 m·s-2; CV = 11.1 ± 5.1%) and deceleration running (≤-3 m·s-2; CV = 11.9 ± 4.5%) (p > 0.05, ES < 0.2). Defenders had a largely higher overall energy expenditure than midfielders and attackers (p < 0.01, ES > 0.6). Overall energy expenditure and cost were largely to very largely correlated with 5 m speed and 22 m agility sprint time and counter movement jump height (r = -0.70-0.69, p < 0.05). The detected variability indicates that global GPS-derived metabolic power data in elite soccer players from a single preseason match should be preferably used for practical applications. Contrary, high-intensity indicators should be interpreted cautiously and repeated match observations are recommended to establish meaningful high-intensity profiles of the players. Differences among playing positions and relationships with explosive physical abilities indicate that metabolic power analyses can provide new insights into the mechanics and energetics of soccer. PMID:28828094

Variability of Metabolic Power Data in Elite Soccer Players During Pre-Season Matches.

PubMed

Hoppe, Matthias Wilhelm; Baumgart, Christian; Slomka, Mirko; Polglaze, Ted; Freiwald, Jürgen

2017-09-01

This study aimed to determine the within-subject variability of GPS-derived metabolic power data in elite soccer players across several pre-season matches and compare the variability of high metabolic power, velocity, acceleration and deceleration running. Additionally, differences in metabolic power data among playing positions and relationships with various physical abilities were also investigated. Metabolic power data from 12 outfield starting players competing in the German Bundesliga were collected during five pre-season matches using GPS-technology (10 Hz). The players were also tested for speed, agility, power and intermittent endurance. Variability of global metabolic power data such as energy expenditure (CV = 2.2-7.0%) was lower than that for high-intensity including time ≥20 W·kg -1 (CV = 14.0-26.2%). Variability of high metabolic power (≥20 W·kg -1 ; CV = 14.1 ± 3.5%) was comparable to that of high velocity (≥15.5 km·h -1 ; CV = 17.0 ± 6.2%), acceleration (≥3 m·s -2 ; CV = 11.1 ± 5.1%) and deceleration running (≤-3 m·s -2 ; CV = 11.9 ± 4.5%) (p > 0.05, ES < 0.2). Defenders had a largely higher overall energy expenditure than midfielders and attackers (p < 0.01, ES > 0.6). Overall energy expenditure and cost were largely to very largely correlated with 5 m speed and 22 m agility sprint time and counter movement jump height (r = -0.70-0.69, p < 0.05). The detected variability indicates that global GPS-derived metabolic power data in elite soccer players from a single preseason match should be preferably used for practical applications. Contrary, high-intensity indicators should be interpreted cautiously and repeated match observations are recommended to establish meaningful high-intensity profiles of the players. Differences among playing positions and relationships with explosive physical abilities indicate that metabolic power analyses can provide new insights into the mechanics and energetics of soccer.

Does shoe heel design influence ground reaction forces and knee moments during maximum lunges in elite and intermediate badminton players?

PubMed Central

Cheung, Jason Tak-Man; Ryu, Jiseon

2017-01-01

Background Lunge is one frequently executed movement in badminton and involves a unique sagittal footstrike angle of more than 40 degrees at initial ground contact compared with other manoeuvres. This study examined if the shoe heel curvature design of a badminton shoe would influence shoe-ground kinematics, ground reaction forces, and knee moments during lunge. Methods Eleven elite and fifteen intermediate players performed five left-forward maximum lunge trials with Rounded Heel Shoe (RHS), Flattened Heel Shoe (FHS), and Standard Heel Shoes (SHS). Shoe-ground kinematics, ground reaction forces, and knee moments were measured by using synchronized force platform and motion analysis system. A 2 (Group) x 3 (Shoe) ANOVA with repeated measures was performed to determine the effects of different shoes and different playing levels, as well as the interaction of two factors on all variables. Results Shoe effect indicated that players demonstrated lower maximum vertical loading rate in RHS than the other two shoes (P < 0.05). Group effect revealed that elite players exhibited larger footstrike angle, faster approaching speed, lower peak horizontal force and horizontal loading rates but higher vertical loading rates and larger peak knee flexion and extension moments (P < 0.05). Analysis of Interactions of Group x Shoe for maximum and mean vertical loading rates (P < 0.05) indicated that elite players exhibited lower left maximum and mean vertical loading rates in RHS compared to FHS (P < 0.01), while the intermediate group did not show any Shoe effect on vertical loading rates. Conclusions These findings indicate that shoe heel curvature would play some role in altering ground reaction force impact during badminton lunge. The differences in impact loads and knee moments between elite and intermediate players may be useful in optimizing footwear design and training strategy to minimize the potential risks for impact related injuries in badminton. PMID:28334016

Validation of an inertial measurement unit for the measurement of jump count and height.

PubMed

MacDonald, Kerry; Bahr, Roald; Baltich, Jennifer; Whittaker, Jackie L; Meeuwisse, Willem H

2017-05-01

To validate the use of an inertial measurement unit (IMU) for the collection of total jump count and assess the validity of an IMU for the measurement of jump height against 3-D motion analysis. Cross sectional validation study. 3D motion-capture laboratory and field based settings. Thirteen elite adolescent volleyball players. Participants performed structured drills, played a 4 set volleyball match and performed twelve counter movement jumps. Jump counts from structured drills and match play were validated against visual count from recorded video. Jump height during the counter movement jumps was validated against concurrent 3-D motion-capture data. The IMU device captured more total jumps (1032) than visual inspection (977) during match play. During structured practice, device jump count sensitivity was strong (96.8%) while specificity was perfect (100%). The IMU underestimated jump height compared to 3D motion-capture with mean differences for maximal and submaximal jumps of 2.5 cm (95%CI: 1.3 to 3.8) and 4.1 cm (3.1-5.1), respectively. The IMU offers a valid measuring tool for jump count. Although the IMU underestimates maximal and submaximal jump height, our findings demonstrate its practical utility for field-based measurement of jump load. Copyright © 2016 Elsevier Ltd. All rights reserved.

MRI findings in soccer players with long-standing adductor-related groin pain and asymptomatic controls.

PubMed

Branci, Sonia; Thorborg, Kristian; Bech, Birthe Højlund; Boesen, Mikael; Nielsen, Michael Bachmann; Hölmich, Per

2015-05-01

Soccer players are commonly affected by long-standing adductor-related groin pain (ARGP), but the clinical significance of MRI findings in these athletes is largely unknown. Our aims were (1) to evaluate whether MRI findings are associated with long-standing ARGP in soccer players, (2) to assess MRI findings in asymptomatic soccer players and non-soccer playing controls. This cross-sectional study included 28 male soccer players with long-standing ARGP, 17 male asymptomatic soccer players and 20 male asymptomatic non-soccer playing athletes of matching age and athletic exposure. Participants underwent identical standardised and reliable clinical examination, and MRI scans (3 T) of the pelvis performed by a blinded observer. Images were consensus rated by three blinded radiologists according to a standardised MRI evaluation protocol. The associations between clinical adductor-related findings and pathological MRI findings were investigated with χ(2) statistics and OR. Central disc protrusion (p=0.027) and higher grades of pubic bone marrow oedema (BMO; p=0.027) were significantly more present in symptomatic players than asymptomatic players. However, up to 71% of asymptomatic soccer players displayed different positive MRI findings, and asymptomatic soccer players had significantly higher odds (OR ranging from 6.3 to 13.3) for BMO, adductor tendinopathy and degenerative changes than non-soccer players. ARGP in soccer players was associated with central disc protrusion and higher grades of pubic BMO. Moreover, positive MRI findings were significantly more frequent in soccer players compared with non-soccer players irrespective of symptoms, suggesting that these MRI changes may be associated with soccer play itself rather than clinical symptoms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Evaluation of the Effect of Core Training on the Leap Power and Motor Characteristics of the 14-16 Years Old Female Volleyball Players

ERIC Educational Resources Information Center

Bilici, Ömer Faruk; Selçuk, Muzaffer

2018-01-01

In this study, it was aimed to assess the effects of core training on the vertical jump strength and some motor characteristics of 14-16 aged female volleyball players. Thirty-four female athletes playing volleyball in Van province participated in the study voluntarily. The average age of volleyball players is 15.47, the weight average is 53.66 kg…

Critical evaluation of a badminton-specific endurance test.

PubMed

Fuchs, Michael; Faude, Oliver; Wegmann, Melissa; Meyer, Tim

2014-03-01

To overcome the limitations of traditional 1-dimensional fitness tests in analyzing physiological properties of badminton players, a badminton-specific endurance test (BST) was created. This study aimed at analyzing the influence of various fitness dimensions on BST performance. 18 internationally competing male German badminton players (22.4 ± 3.2 y, 79.2 ± 7.7 kg, 1.84 ± 0.06 m, world-ranking position [WRP] 21-501) completed a straight-sprint test, a change-of-direction speed test, various jump tests (countermovement jump, drop jump, standing long jump), a multistage running test (MST), and the BST. During this on-court field test players have to respond to a computerized sign indicating direction and speed of badminton-specific movements by moving into the corresponding corners. Significant correlations were found between performance in MST and BST (individual anaerobic threshold [IAT], r = .63, P = .005; maximum velocity [Vmax], r = .60, P = .009). A negative correlation (r = -.59, P = .014) was observed between IAT in BST and drop-jump contact time. No further associations between performance indices could be detected. Apart from a small portion explained by MST results (IAT, R2 = .40; Vmax, R2 = .36), the majority of BST performance cannot be explained by the determined physiological correlates. Moreover, it was impossible to predict the WRP of a player on the basis of BST results (r = -.15, P = .55). Neither discipline-specific performance nor basic physiological properties were appropriately reflected by a BST in elite badminton players. This does not substantiate its validity for regular use as a testing tool. However, it may be useful for monitoring on-court training sessions.

Influence of prior knowledge of exercise duration on pacing strategies during game-based activities.

PubMed

Gabbett, Tim J; Walker, Ben; Walker, Shane

2015-04-01

To investigate the influence of prior knowledge of exercise duration on the pacing strategies employed during game-based activities. Twelve semiprofessional team-sport athletes (mean ± SD age 22.8 ± 2.1 y) participated in this study. Players performed 3 small-sided games in random order. In one condition (Control), players were informed that they would play the small-sided game for 12 min and then completed the 12-min game. In a 2nd condition (Deception), players were told that they would play the small-sided game for 6 minutes, but after completing the 6-min game, they were asked to complete another 6 min. In a 3rd condition (Unknown), players were not told how long they would be required to play the small-sided game, but the activity was terminated after 12 min. Movement was recorded using a GPS unit sampling at 10 Hz. Post hoc inspection of video footage was undertaken to count the number of possessions and the number and quality of disposals. Higher initial intensities were observed in the Deception (130.6 ± 3.3 m/min) and Unknown (129.3 ± 2.4 m/min) conditions than the Control condition (123.3 ± 3.4 m/min). Greater amounts of high-speed running occurred during the initial phases of the Deception condition, and more low-speed activity occurred during the Unknown condition. A moderately greater number of total skill involvements occurred in the Unknown condition than the Control condition. These findings suggest that during game-based activities, players alter their pacing strategy based on the anticipated endpoint of the exercise bout.

Effects of emphasising opposition and cooperation on collective movement behaviour during football small-sided games.

PubMed

Gonçalves, B; Marcelino, R; Torres-Ronda, L; Torrents, C; Sampaio, J

2016-07-01

Optimizing collective behaviour helps to increase performance in mutual tasks. In team sports settings, the small-sided games (SSG) have been used as key context tools to stress out the players' awareness about their in-game required behaviours. Research has mostly described these behaviours when confronting teams have the same number of players, disregarding the frequent situations of low and high inequality. This study compared the players' positioning dynamics when manipulating the number of opponents and teammates during professional and amateur football SSG. The participants played 4v3, 4v5 and 4v7 games, where one team was confronted with low-superiority, low- and high-inferiority situations, and their opponents with low-, medium- and high-cooperation situations. Positional data were used to calculate effective playing space and distances from each player to team centroid, opponent team centroid and nearest opponent. Outcomes suggested that increasing the number of opponents in professional teams resulted in moderate/large decrease in approximate entropy (ApEn) values to both distance to team and opponent team centroid (i.e., the variables present higher regularity/predictability pattern). In low-cooperation game scenarios, the ApEn in amateurs' tactical variables presented a moderate/large increase. The professional teams presented an increase in the distance to nearest opponent with the increase of the cooperation level. Increasing the number of opponents was effective to overemphasise the need to use local information in the positioning decision-making process from professionals. Conversely, amateur still rely on external informational feedback. Increasing the cooperation promoted more regularity in spatial organisation in amateurs and emphasise their players' local perceptions.

The match-to-match variation of match-running in elite female soccer.

PubMed

Trewin, Joshua; Meylan, César; Varley, Matthew C; Cronin, John

2018-02-01

The purpose of this study was to examine the match-to-match variation of match-running in elite female soccer players utilising GPS, using full-match and rolling period analyses. Longitudinal study. Elite female soccer players (n=45) from the same national team were observed during 55 international fixtures across 5 years (2012-2016). Data was analysed using a custom built MS Excel spreadsheet as full-matches and using a rolling 5-min analysis period, for all players who played 90-min matches (files=172). Variation was examined using co-efficient of variation and 90% confidence limits, calculated following log transformation. Total distance per minute exhibited the smallest variation when both the full-match and peak 5-min running periods were examined (CV=6.8-7.2%). Sprint-efforts were the most variable during a full-match (CV=53%), whilst high-speed running per minute exhibited the greatest variation in the post-peak 5-min period (CV=143%). Peak running periods were observed as slightly more variable than full-match analyses, with the post-peak period very-highly variable. Variability of accelerations (CV=17%) and Player Load (CV=14%) was lower than that of high-speed actions. Positional differences were also present, with centre backs exhibiting the greatest variation in high-speed movements (CV=41-65%). Practitioners and researchers should account for within player variability when examining match performances. Identification of peak running periods should be used to assist worst case scenarios. Whilst micro-sensor technology should be further examined as to its viable use within match-analyses. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Age-Related, Sport-Specific Adaptions of the Shoulder Girdle in Elite Adolescent Tennis Players

PubMed Central

Cools, Ann M.; Palmans, Tanneke; Johansson, Fredrik R.

2014-01-01

Context: Tennis requires repetitive overhead movements that can lead to upper extremity injury. The scapula and the shoulder play a vital role in injury-free playing. Scapular dysfunction and glenohumeral changes in strength and range of motion (ROM) have been associated with shoulder injury in the overhead athlete. Objective: To compare scapular position and strength and shoulder ROM and strength between Swedish elite tennis players of 3 age categories (<14, 14–16, and >16 years). Design: Cross-sectional study. Setting: Tennis training sports facilities. Patients or Other Participants: Fifty-nine adolescent Swedish elite tennis players (ages 10–20 years) selected based on their national ranking. Main Outcome Measure(s): We used a clinical screening protocol with a digital inclinometer and a handheld dynamometer to measure scapular upward rotation at several angles of arm elevation, isometric scapular muscle strength, glenohumeral ROM, and isometric rotator cuff strength. Results: Players older than 16 years showed less scapular upward rotation on the dominant side at 90° and 180° (P < .05). Although all absolute scapular muscle strength values increased with age, there was no change in the body-weight–normalized strength of the middle (P = .9) and lower (P = .81) trapezius or serratus anterior (P = .17). Glenohumeral internal-rotation ROM and total ROM tended to decrease, but this finding was not statistically significant (P = .052 and P = .06, respectively). Whereas normalized internal-rotator strength increased from 14 to 16 years to older than 16 years (P = .009), normalized external-rotator and supraspinatus strength remained unchanged. Conclusions: Age-related changes in shoulder and scapular strength and ROM were apparent in elite adolescent tennis players. Future authors should examine the association of these adaptations with performance data and injury incidence. PMID:25098662

Age-related, sport-specific adaptions of the shoulder girdle in elite adolescent tennis players.

PubMed

Cools, Ann M; Palmans, Tanneke; Johansson, Fredrik R

2014-01-01

Tennis requires repetitive overhead movements that can lead to upper extremity injury. The scapula and the shoulder play a vital role in injury-free playing. Scapular dysfunction and glenohumeral changes in strength and range of motion (ROM) have been associated with shoulder injury in the overhead athlete. To compare scapular position and strength and shoulder ROM and strength between Swedish elite tennis players of 3 age categories (<14, 14-16, and >16 years). Cross-sectional study. Tennis training sports facilities. Fifty-nine adolescent Swedish elite tennis players (ages 10-20 years) selected based on their national ranking. We used a clinical screening protocol with a digital inclinometer and a handheld dynamometer to measure scapular upward rotation at several angles of arm elevation, isometric scapular muscle strength, glenohumeral ROM, and isometric rotator cuff strength. Players older than 16 years showed less scapular upward rotation on the dominant side at 90° and 180° (P < .05). Although all absolute scapular muscle strength values increased with age, there was no change in the body-weight-normalized strength of the middle (P = .9) and lower (P = .81) trapezius or serratus anterior (P = .17). Glenohumeral internal-rotation ROM and total ROM tended to decrease, but this finding was not statistically significant (P = .052 and P = .06, respectively). Whereas normalized internal-rotator strength increased from 14 to 16 years to older than 16 years (P = .009), normalized external-rotator and supraspinatus strength remained unchanged. Age-related changes in shoulder and scapular strength and ROM were apparent in elite adolescent tennis players. Future authors should examine the association of these adaptations with performance data and injury incidence.

Predicting performance and injury resilience from movement quality and fitness scores in a basketball team over 2 years.

PubMed

McGill, Stuart M; Andersen, Jordan T; Horne, Arthur D

2012-07-01

The purpose of this study was to see if specific tests of fitness and movement quality could predict injury resilience and performance in a team of basketball players over 2 years (2 playing seasons). It was hypothesized that, in a basketball population, movement and fitness scores would predict performance scores and that movement and fitness scores would predict injury resilience. A basketball team from a major American university (N = 14) served as the test population in this longitudinal trial. Variables linked to fitness, movement ability, speed, strength, and agility were measured together with some National Basketball Association (NBA) combine tests. Dependent variables of performance indicators (such as games and minutes played, points scored, assists, rebounds, steal, and blocks) and injury reports were tracked for the subsequent 2 years. Results showed that better performance was linked with having a stiffer torso, more mobile hips, weaker left grip strength, and a longer standing long jump, to name a few. Of the 3 NBA combine tests administered here, only a faster lane agility time had significant links with performance. Some movement qualities and torso endurance were not linked. No patterns with injury emerged. These observations have implications for preseason testing and subsequent training programs in an attempt to reduce future injury and enhance playing performance.

Depression, Anxiety, and Alcohol Use in Elite Rugby League Players Over a Competitive Season.

PubMed

Du Preez, Etienne J; Graham, Kenneth S; Gan, Thomas Y; Moses, Bassam; Ball, Chris; Kuah, Donald E

2017-11-01

To assess the prevalence of symptoms of depression, anxiety, and rates of alcohol misuse in elite rugby league players in Australasia. A cross-sectional, epidemiological study with repeated measures. Surveys were conducted during the 2015 preseason and in-season. Four hundred four elite rugby league players participated preseason and 278 players in-season. Symptoms of depression were measured using the Patient Health Questionnaire-9 scale, symptoms of generalized anxiety disorder (GAD) with the GAD-7 scale, and the Alcohol Use Disorders Identification Test Consumption scale was used to assess hazardous alcohol use. The overall prevalence of depression was 12.6% preseason and 10.1% in-season. Generalized anxiety disorder had a prevalence of 14.6% and 10.1% for these 2 periods. Overall, 68.6% of players had hazardous levels of alcohol use preseason, and 62.8% in-season. There was no significant difference for any of the main outcomes between the periods. Players with a history of mental illnesses had 5.62 greater odds (95% confidence interval [CI], 2.62-12.04) of depression than those without during preseason, and 22.08 greater odds (95% CI, 7.77-62.71) in-season. Players reporting ≥3 previous concussions had 2.02 greater odds (95% CI, 1.07-3.82) of depression than those reporting ≤2 in the preseason sample. Rugby league players have a lower prevalence of depression compared with studies of the general population and other athletes, but a higher prevalence of GAD, and high rates of alcohol misuse. Clubs may consider implementing regular screening for these conditions. Further prospective research to determine causality of independent factors is required.

Visual and skill effects on soccer passing performance, kinematics, and outcome estimations

PubMed Central

Basevitch, Itay; Tenenbaum, Gershon; Land, William M.; Ward, Paul

2015-01-01

The role of visual information and action representations in executing a motor task was examined from a mental representations approach. High-skill (n = 20) and low-skill (n = 20) soccer players performed a passing task to two targets at distances of 9.14 and 18.29 m, under three visual conditions: normal, occluded, and distorted vision (i.e., +4.0 corrective lenses, a visual acuity of approximately 6/75) without knowledge of results. Following each pass, participants estimated the relative horizontal distance from the target as the ball crossed the target plane. Kinematic data during each pass were also recorded for the shorter distance. Results revealed that performance on the motor task decreased as a function of visual information and task complexity (i.e., distance from target) regardless of skill level. High-skill players performed significantly better than low-skill players on both the actual passing and estimation tasks, at each target distance and visual condition. In addition, kinematic data indicated that high-skill participants were more consistent and had different kinematic movement patterns than low-skill participants. Findings contribute to the understanding of the underlying mechanisms required for successful performance in a self-paced, discrete and closed motor task. PMID:25784886

Skating start propulsion: three-dimensional kinematic analysis of elite male and female ice hockey players.

PubMed

Shell, Jaymee R; Robbins, Shawn M K; Dixon, Philippe C; Renaud, Philippe J; Turcotte, René A; Wu, Tom; Pearsall, David J

2017-09-01

The forward skating start is a fundamental skill for male and female ice hockey players. However, performance differences by athlete's sex cannot be fully explained by physiological variables; hence, other factors such as skating technique warrant examination. Therefore, the purpose of this study was to evaluate the body movement kinematics of ice hockey skating starts between elite male and female ice hockey participants. Male (n = 9) and female (n = 10) elite ice hockey players performed five forward skating start accelerations. An 18-camera motion capture system placed on the arena ice surface captured full-body kinematics during the first seven skating start steps within 15 meters. Males' maximum skating speeds were greater than females. Skating technique sex differences were noted: in particular, females presented ~10° lower hip abduction throughout skating stance as well as ~10° greater knee extension at initial ice stance contact, conspicuously followed by a brief cessation in knee extension at the moment of ice contact, not evident in male skaters. Further study is warranted to explain why these skating technique differences exist in relation to factors such as differences in training, equipment, performance level, and anthropometrics.

ACTN3 genotypes of Rugby Union players: distribution, power output and body composition.

PubMed

Bell, W; Colley, J P; Evans, W D; Darlington, S E; Cooper, S-M

2012-01-01

To identify the distribution and explore the relationship between ACTN3 genotypes and power and body composition phenotypes. Case control and association studies were employed using a homogeneous group of players (n = 102) and a control group (n = 110). Power-related phenotypes were measured using the counter movement jump (CMJ) and body composition phenotypes by dual-energy X-ray absorptiometry (DXA). Statistics used were Pearson's chi-square, ANCOVA, coefficients of correlation and independent t-tests. Genotyping was carried out using polymerase chain reaction followed by enzymatic Ddel digestion. Genotype proportions of players were compared with controls (p = 0.07). No significant genotype differences occurred between forwards or backs (p = 0.822) or within-forwards (p = 0.882) or within-backs (p = 0.07). Relative force and velocity were significantly larger in backs, power significantly greater in forwards; in body composition, all phenotypes were significantly greater in forwards than backs. Correlations between phenotypes were greater for the RX genotype (p = 0.05-0.01). Relationships between ACTN3 genotypes and power or body composition-related phenotypes were not significant. As fat increased, power-related phenotypes decreased. As body composition increased, power-related phenotypes increased.

Epidemiology, Treatment, and Prevention of Lumbar Spine Injuries in Major League Baseball Players.

PubMed

Camp, Christopher L; Conti, Matthew S; Sgroi, Terrance; Cammisa, Frank P; Dines, Joshua S

2016-01-01

In recent years, increased attention has been paid to injuries occurring in Major League Baseball (MLB) players. Although most of the current orthopedic literature regarding baseball injuries pertains to the shoulder and elbow, lumbar spine injuries are another common reason for time out of play. Back and core injuries may represent as many as 12% of all injuries that result in time out of play from MLB. This high rate of injury is likely related to the critical role that the spine plays in every major baseball-related movement. Linking the upper extremities to the hips and lower extremities, a healthy, strong, and stable spine and core is a prerequisite for performance in all levels of baseball. It has been well documented that baseball players with poor spinal control and stabilization are at increased risk for future injury. Common etiologies of lumbar injuries include stress fractures, muscle injury, annular tears with or without disc herniation, facet joint pain, sacroiliac joint pain, and stenosis. This review discusses the epidemiology of spinal injuries in baseball. Special attention is paid to the role of the spine in baseball-related activities, common injuries, tips for making the correct diagnosis, treatment options, outcomes, rehabilitation, and injury prevention.

Effects of neuromuscular joint facilitation on baseball pitching velocity and electromechanical reaction times of the teres major of young amateur baseball players.

PubMed

Wu, Peng; Huo, Ming; Maruyama, Hitoshi

2013-11-01

[Purpose] The aim of this study was to investigate the changes of baseball pitching velocity and electromechanical reaction times (EMG-RT) of the teres major of young amateur baseball players after neuromuscular joint facilitation (NJF) treatment. [Subjects] The subjects were 18 healthy males who were divided into two groups: a NJF group and a control group. The NJF group consisted of 10 subjects, and the control group consisted of 8 subjects. [Methods] Participants in the NJF group received NJF treatment. The baseball pitching velocity, the EMG-RT, the premotor time (PMT), and the motor time (MT) during shoulder internal rotation movement were measured before and after 8 weeks of exercise. [Results] There were no significant differences among the results of the control group. In the NJF group, there were significant differences in baseball pitching velocity, EMG-RT and MT after NJF treatment. [Conclusion] NJF intervention shortens not only EMG-RT but also MT, which implies that NJF is effective for motor processes. Since the baseball pitching velocity increased, NJF may be recommended for the improvement of the performance of baseball players.

Ultrasound assessment of the posterior circumflex humeral artery in elite volleyball players: Aneurysm prevalence, anatomy, branching pattern and vessel characteristics.

PubMed

van de Pol, Daan; Maas, Mario; Terpstra, Aart; Pannekoek-Hekman, Marja; Alaeikhanehshir, Sena; Kuijer, P Paul F M; Planken, R Nils

2017-03-01

To determine the prevalence of posterior circumflex humeral artery (PCHA) aneurysms and vessel characteristics of the PCHA and deep brachial artery (DBA) in elite volleyball players. Two-hundred and eighty players underwent standardized ultrasound assessment of the dominant arm by a vascular technologist. Assessment included determination of PCHA aneurysms (defined as segmental vessel dilatation ≥150 %), PCHA and DBA anatomy, branching pattern, vessel course and diameter. The PCHA and DBA were identified in 100 % and 93 % (260/280) of cases, respectively. The prevalence of PCHA aneurysms was 4.6 % (13/280). All aneurysms were detected in proximal PCHA originating from the axillary artery (AA). The PCHA originated from the AA in 81 % of cases (228/280), and showed a curved course dorsally towards the humeral head in 93 % (211/228). The DBA originated from the AA in 73 % of cases (190/260), and showed a straight course parallel to the AA in 93 % (177/190). PCHA aneurysm prevalence in elite volleyball players is high and associated with a specific branching type: a PCHA that originates from the axillary artery. Radiologists should have a high index of suspicion for this vascular overuse injury. For the first time vessel characteristics and reference values are described to facilitate ultrasound assessment. • Prevalence of PCHA aneurysms is 4.6 % among elite volleyball players. • All aneurysms are in proximal PCHA that originates directly from AA. • Vessel characteristics and reference values are described to facilitate US assessment. • Mean PCHA and DBA diameters can be used as reference values. • Radiologists need a high index of suspicion for this vascular overuse injury.

Morphological, Physiological and Skating Performance Profiles of Male Age-Group Elite Ice Hockey Players.

PubMed

Allisse, Maxime; Sercia, Pierre; Comtois, Alain-Steve; Leone, Mario

2017-09-01

The purpose of this study was to describe the evolution of morphological, physiological and skating performance profiles of elite age-group ice hockey players based on repeated measures spread over one season. In addition, the results of fitness tests and training programs performed in off-ice conditions and their relationship with skating performance were analyzed. Eighteen high level age-group ice hockey players (13.1 ± 0.6 years) were assessed off and on-ice at the beginning and at the end of the hockey season. A third evaluation was also conducted at the beginning of the following hockey season. The players were taller, heavier, and showed bone breadths and muscle girths above the reference population of the same age. Muscular variables improved significantly during and between the two hockey seasons (p < 0.05). However, maximal aerobic power improved only during the off-season. All skating performance tests exhibited significant enhancements during the hockey season, but not during the off-season where some degradation was observed. Finally, weak observed variances (generally <20% of the explained variance) between physiological variables measured off-ice and on-ice skating performance tests indicated important gaps, both in the choice of the off-ice assessment tools as well as in training methods conventionally used. The reflection on the best way to assess and train hockey players certainly deserves to be continued.

Morphological, Physiological and Skating Performance Profiles of Male Age-Group Elite Ice Hockey Players

PubMed Central

Allisse, Maxime; Sercia, Pierre; Comtois, Alain-Steve; Leone, Mario

2017-01-01

Abstract The purpose of this study was to describe the evolution of morphological, physiological and skating performance profiles of elite age-group ice hockey players based on repeated measures spread over one season. In addition, the results of fitness tests and training programs performed in off-ice conditions and their relationship with skating performance were analyzed. Eighteen high level age-group ice hockey players (13.1 ± 0.6 years) were assessed off and on-ice at the beginning and at the end of the hockey season. A third evaluation was also conducted at the beginning of the following hockey season. The players were taller, heavier, and showed bone breadths and muscle girths above the reference population of the same age. Muscular variables improved significantly during and between the two hockey seasons (p < 0.05). However, maximal aerobic power improved only during the off-season. All skating performance tests exhibited significant enhancements during the hockey season, but not during the off-season where some degradation was observed. Finally, weak observed variances (generally <20% of the explained variance) between physiological variables measured off-ice and on-ice skating performance tests indicated important gaps, both in the choice of the off-ice assessment tools as well as in training methods conventionally used. The reflection on the best way to assess and train hockey players certainly deserves to be continued. PMID:28828080

Smartkuber: A Serious Game for Cognitive Health Screening of Elderly Players.

PubMed

Boletsis, Costas; McCallum, Simon

2016-08-01

The goal of this study was to design and develop a serious game for cognitive health screening of the elderly, namely Smartkuber, and evaluate its construct, criteria (concurrent and predictive), and content validity, assessing its relationship with the Montreal Cognitive Assessment (MoCA) test. Furthermore, the study aims to evaluate the elderly players' game experience with Smartkuber. Thirteen older adults were enrolled in the study. The game was designed and developed by a multidisciplinary team. The study follows a mixed methodological approach, utilizing the In-Game Experience Questionnaire to assess the players' game experience and a correlational study, to examine the relationship between the Smartkuber and MoCA scores. The learning effect is also examined by comparing the mean game scores of the first and last game sessions of each player (Delta scores). All 13 participants (mean age: 68.69, SD: 7.24) successfully completed the study. Smartkuber demonstrated high concurrent validity with the MoCA test (r = 0.81, P = 0.001) and satisfying levels of predictive and content validity. The Delta scores showed no statistically significant differences in scoring, thus indicating no learning effects during the Smartkuber game sessions. The study shows that Smartkuber is a promising tool for cognitive health screening, providing an entertaining and motivating gaming experience to elderly players. Limitations of the study and future directions are discussed.

The development and validation of a golf swing and putt skill assessment for children.

PubMed

Barnett, Lisa M; Hardy, Louise L; Brian, Ali S; Robertson, Sam

2015-03-01

The aim was to describe development of a process-oriented instrument designed to assess the golf swing and putt stroke, and to assess the instrument's discriminative validity in terms of age and reliability (intra-rater and re-test). A Delphi consultation (with golf industry professionals and researchers in movement skill assessment) was used to develop an assessment for each skill based on existing skill assessment protocols. Each skill had six components to be marked as present/absent. Individual scores were based on the number of performance components successfully demonstrated over two trials for each skill (potential score range 0 to 24). Children (n = 43) aged 6-10 years (M = 7.8 years, SD = 1.3) were assessed in both skills live in the field by one rater at Time 1(T1). A subset of children (n = 28) had consent for assessments to be videoed. Six weeks later 19 children were reassessed, five days apart (T2, T3). An ANOVA assessed discriminative validity i.e. whether skill competence at T1 differed by age (6 years, 7/8 years and 9/10 years). Intraclass correlations (ICC) assessed intra-rater reliability between the live and video assessment at T1 and test-retest reliability (between T2 and T3). Paired t-tests assessed any systematic differences between live and video assessments (T1) and between T2 and T3. Older children were more skilled (F (2, 40) = 11.18, p < 0.001). The live assessment reflected the video assessment (ICC = 0.79, 95% CI 0.59, 0.90) and scores did not differ between live and video assessments. Test retest reliability was acceptable (ICC = 0.60, 95% CI 0.23, 0.82), although the mean score was slightly higher at retest. This instrument could be used reliably by golf coaches and physical education teachers as part of systematic early player assessment and feedback. Key pointsGolf is becoming an increasingly popular sport among young children, however there is no standard protocol available to assess and identify skill deficits, mastery level, and talent identification in beginner young golf players.Process rather than product oriented outcomes better identify areas of skill deficit in young children.The proposed swing and putt instrument can reliably identify skill deficits in children of elementary school age who are new to golf and can be used by a range of stakeholders including golf coaches, generalist sport coaches and physical education teachers.

The Development and Validation of a Golf Swing and Putt Skill Assessment for Children

PubMed Central

Barnett, Lisa M.; Hardy, Louise L.; Brian, Ali S.; Robertson, Sam

2015-01-01

The aim was to describe development of a process-oriented instrument designed to assess the golf swing and putt stroke, and to assess the instrument’s discriminative validity in terms of age and reliability (intra-rater and re-test). A Delphi consultation (with golf industry professionals and researchers in movement skill assessment) was used to develop an assessment for each skill based on existing skill assessment protocols. Each skill had six components to be marked as present/absent. Individual scores were based on the number of performance components successfully demonstrated over two trials for each skill (potential score range 0 to 24). Children (n = 43) aged 6-10 years (M = 7.8 years, SD = 1.3) were assessed in both skills live in the field by one rater at Time 1(T1). A subset of children (n = 28) had consent for assessments to be videoed. Six weeks later 19 children were reassessed, five days apart (T2, T3). An ANOVA assessed discriminative validity i.e. whether skill competence at T1 differed by age (6 years, 7/8 years and 9/10 years). Intraclass correlations (ICC) assessed intra-rater reliability between the live and video assessment at T1 and test-retest reliability (between T2 and T3). Paired t-tests assessed any systematic differences between live and video assessments (T1) and between T2 and T3. Older children were more skilled (F (2, 40) = 11.18, p < 0.001). The live assessment reflected the video assessment (ICC = 0.79, 95% CI 0.59, 0.90) and scores did not differ between live and video assessments. Test retest reliability was acceptable (ICC = 0.60, 95% CI 0.23, 0.82), although the mean score was slightly higher at retest. This instrument could be used reliably by golf coaches and physical education teachers as part of systematic early player assessment and feedback. Key points Golf is becoming an increasingly popular sport among young children, however there is no standard protocol available to assess and identify skill deficits, mastery level, and talent identification in beginner young golf players. Process rather than product oriented outcomes better identify areas of skill deficit in young children. The proposed swing and putt instrument can reliably identify skill deficits in children of elementary school age who are new to golf and can be used by a range of stakeholders including golf coaches, generalist sport coaches and physical education teachers. PMID:25729302

Locomotion characteristics and match-induced impairments in physical performance in male elite team handball players.

PubMed

Michalsik, L B; Aagaard, P; Madsen, K

2013-07-01

The purpose of this study was to determine the physical demands and match-induced impairments in physical performance in male elite Team Handball (TH) players in relation to playing position. Male elite TH field players were closely observed during 6 competitive seasons. Each player (wing players: WP, pivots: PV, backcourt players: BP) was evaluated during match-play using video recording and subsequently performing locomotion match analysis. A total distance of 3 627±568 m (group means±SD) was covered per match with a total effective playing time (TPT) of 53:51±5:52 min:s, while full-time players covered 3 945±538 m. The mean speed was 6.40±1.01 km · h - 1. High-intensity running constituted only 1.7±0.9% of TPT per match corresponding to 7.9±4.9% of the total distance covered. An average of 1 482.4±312.6 activity changes per player (n=82) with 53.2±14.1 high-intensity runs were observed per match. Total distance covered was greater in BP (3 765±532 m) and WP (3 641±501 m) than PV (3 295±495 m) (p<0.05), and WP performed more high-intensity running (10.9±5.7% of total distance covered) than PV (8.5±4.3%, p<0.05) and BP (6.2±3.2%, p<0.01). The amount of high-intensity running was lower (p<0.05) in the second (130.4±38.4 m) than in the first half (155.3±47.6 m) corresponding to a decrease of 16.2%.In conclusion, modern male elite TH is a complex team sport that comprises several types of movement categories, which during match-play place moderate-to-high demands on intermittent endurance running capacity and where the amount of high-intensity running may be high during brief periods of the match. Signs of fatigue-related changes were observed in terms of temporary impaired physical performance, since the amount of high-intensity running was reduced in the second half. Notably, physical demands differed between playing positions, with WP demonstrating a more intensive activity pattern than BP and PV, respectively. © Georg Thieme Verlag KG Stuttgart · New York.

Absolute and Relative Training Load and Its Relation to Fatigue in Football

PubMed Central

Zurutuza, Unai; Castellano, Julen; Echeazarra, Ibon; Casamichana, David

2017-01-01

The aim of the study was to assess the relationship of external and internal training load (TL) indicators with the objective and subjective fatigue experienced by 15 semi-professional football players, over eight complete weeks of the competition period in the 2015–2016 season, which covered microcycles from 34th to 41st. The maximum heart rate (HRmax) and maximum speed (Vmax) of all the players were previously measured in specific tests. The TL was monitored via questionnaires on rating of perceived exertion (RPE), pulsometers and GPS devices, registering the variables: total distance (TD), player load 2D (PL2D), TD at >80% of the Vmax (TD80), TD in deceleration at < -2 m⋅sec-2 (TDD <-2), TD in acceleration >2 m⋅sec-2 (TDA >2), Edwards (ED), time spent at between 50 and 80% (50–80% HRmax), 80–90% (80–90% HRmax), and >90% of the HRmax (>90% HRmax), and RPE both respiratory/thoracic (RPEres) and leg/muscular (RPEmus). All the variables were analyzed taking into account both the absolute values accumulated over the week and the normalized values in relation to individual mean competition values. Neuromuscular fatigue was measured objectively using the countermovement jump test and subjectively via the Total Quality Recovery (TQR) scale questionnaire. Analytical correlation techniques were later applied within the general linear model. There is a correlation between the fatigue experienced by the player, assessed objectively and subjectively, and the load accumulated over the week, this being assessed in absolute and relative terms. Specifically, the load relative to competition correlated with the physical variables TD (-0.279), PL2D (-0.272), TDD < -2 (-0.294), TDA >2 (-0.309), and sRPEmus (-0.287). The variables related to heart rate produced a higher correlation with TQR. There is a correlation between objectively and subjectively assessed fatigue and the accumulated TL of a player over the week, with a higher sensitivity being shown when compared to the values related to the demands of competition. Monitoring load and assessing fatigue, we are closer to knowing what the prescription of an adequate dose of training should be in order for a player to be as fresh as possible and in top condition for a match. Normalizing training demands with respect to competition could be an appropriate strategy for individualizing player TL. PMID:28634456

Blocking landing techniques in volleyball and the possible association with anterior cruciate ligament injury.

PubMed

Zahradnik, David; Jandacka, Daniel; Holcapek, Michal; Farana, Roman; Uchytil, Jaroslav; Hamill, Joseph

2018-04-01

The number and type of landings performed after blocking during volleyball matches has been related to the potential risk of ACL injury. The aim of the present study was to determine whether gender affects the frequency of specific blocking landing techniques with potential risk of ACL injury from the perspective of foot contact and subsequent movement after the block used by volleyball players during competitive matches. Three matches involving four female volleyball teams (fourteen sets) and three matches involving four male volleyball teams (thirteen sets) in the Czech Republic were analyzed for this study. A Pearson chi-square test of independence was used to detect the relationship between gender and different blocking techniques. The results of the present study showed that gender affected single-leg landings with subsequent movement in lateral direction and double-leg landings. Although the total number of landings was lower for male athletes than for female athletes, a larger portion of male athletes demonstrated single leg landings with a subsequent movement than female athletes. Single leg landings with a subsequent movement have a higher potential risk of ACL injury.

Exploring patterns of movement suspension in pedestrian mobility.

PubMed

Orellana, Daniel; Wachowicz, Monica

2011-01-01

One of the main tasks in analyzing pedestrian movement is to detect places where pedestrians stop, as those places usually are associated with specific human activities, and they can allow us to understand pedestrian movement behavior. Very few approaches have been proposed to detect the locations of stops in positioning data sets, and they often are based on selecting the location of candidate stops as well as potential spatial and temporal thresholds according to different application requirements. However, these approaches are not suitable for analyzing the slow movement of pedestrians where the inaccuracy of a nondifferential global positioning system commonly used for movement tracking is so significant that it can hinder the selection of adequate thresholds. In this article, we propose an exploratory statistical approach to detect patterns of movement suspension using a local indicator of spatial association (LISA) in a vector space representation. Two different positioning data sets are used to evaluate our approach in terms of exploring movement suspension patterns that can be related to different landscapes: players of an urban outdoor mobile game and visitors of a natural park. The results of both experiments show that patterns of movement suspension were located at places such as checkpoints in the game and different attractions and facilities in the park. Based on these results, we conclude that using LISA is a reliable approach for exploring movement suspension patterns that represent the places where the movement of pedestrians is temporally suspended by physical restrictions (e.g., checkpoints of a mobile game and the route choosing points of a park).

Effects of weather anomalies on the intellectual performance: Chess mistakes of the world top-ranked players

NASA Astrophysics Data System (ADS)

Mika, J.; Verőci, Zs.; Fülöp, A.; Hirsch, T.; Dúll, A.

2009-04-01

Weather disturbances like fronts, influence human biorhythm, our biological balance becomes manipulated, and adaptation mechanisms are impaired. Our working hypothesis is that even the best chess players of the world are not exceptions from this rule. As their movements on the chess board, as well as the best possible ones, if they missed to make, are already assessed by computers objectively, we can use this game as a model of intellectual performance. By the date of the Abstract edition, 580 wrong chess moves were selected with the threshold of over 1/3 peasant to be lost. I.e. this is the minimum difference between the assessment of the positions after the best possible and the really performed move. (Obviously, all moves both sides in ca. the same number of games were checked, i.e. over 35,000 moves were assessed.) For assessing the moves, the most popular database is MegaDatabase 2006 (ChessBase- Hamburg), Chess Informant Expert from Chess Informant Beograd and the program ChessBase 9.0 together with the engines Fritz 10, Rybka 2.3, Junior 10. First of all the World Chess Champions, Karpov, Kasparov, Kramnik and Anand were examined played in the traditional big chess tournaments, category 19th and more (average rating more the 2701 Elo-points). We further selected the games by the top-ranked players of the world between 2005 and 2008. This selection is explained by the likely fact that they make the less wrong moves for simply the lack of chess understanding, moreover, as full professionals, they allow the minimum of non-weather disturbing circumstances (e.g. imperfect sleeping before the game, etc.). Their moves were selected as (i) very wrong move with more than 3.0 differences, (i.e. unforced loss of a knight, or a bishop, (ii) very weak move with an assessment of 1.0-3.0, (i.e. unforced loss between one peasant and one bishop/knight) and (iii) weak move with less than 1.0 assessment of the passed chance, or unforced loss of less than one peasant. These new data on mental behavior are statistically compared to a common set of diurnal meteorological parameters, including various near-surface and lower troposphere temperature values, sea-level pressures, relative topographies, precipitation amount and existence (duration) and wind speed. The data and the aerologic fields are retrieved from the ECMWF ERA-40 (until 2002) and ECMWF operational analysis (after 2002) for the date and site of the individual mistakes. According to our preliminary results, the wrong moves fall to the lower or higher than average parts of the diurnal mean temperature distribution. Even if we should be careful because of the well known bi-modal distribution of the temperature (if not performing any seasonal correction), but, even after considering these differences the best players make more frequent mistakes in case of higher or lower than normal temperature situations. Another preliminary experience is that decreasing tendency of the RT850/500 hPa relative topography also indicates increase of wrong and very wrong moves. After performing this analysis, the result will be compared to the better known empirical paradigms of medical meteorology and experimental psychology.

Return to Training and Playing After Acute Lisfranc Injuries in Elite Professional Soccer and Rugby Players.

PubMed

Deol, Rupinderbir Singh; Roche, Andrew; Calder, James D F

2016-01-01

Lisfranc joint injuries are increasingly recognized in elite soccer and rugby players. Currently, no evidence-based guidelines exist on time frames for return to training and competition after surgical treatment. To assess the time to return to training and playing after Lisfranc joint injuries. Case series; Level of evidence, 4. A consecutive series of 17 professional soccer and rugby players in the English Premier/Championship leagues was assessed using prospectively collected data. All were isolated injuries sustained during training or competitive matches. Each player had clinical and radiological evidence of an unstable Lisfranc injury and required surgical treatment. A standardized postoperative regimen was used. The minimum follow-up time was 2 years. Clinical and radiological follow-up was obtained in all 17 players. Seven players had primarily ligamentous injuries, and 10 had bony injuries. The time from injury to fixation ranged from 8 to 31 days, and hardware was removed at 16 weeks postoperatively. One athlete retired after a ligamentous injury; the remaining 16 players returned to training and full competition. Excluding the retired player, the mean time to return to training was 20.1 weeks (range, 18-24 weeks) and to full competition was 25.3 weeks (range, 21-31 weeks). There was a significant difference between the mean time to return to competition for rugby (27.8 weeks) and soccer players (24.1 weeks; P = .02) and for ligamentous (22.5 weeks) compared with bony injuries (26.9 weeks; P = .003). Three patients suffered deep peroneal nerve sensation loss, from which 1 patient did not fully recover. Return to competitive elite-level soccer and rugby is possible after surgically treated Lisfranc injuries. Return to training can take up to 24 weeks and return to playing up to 31 weeks, with bony injuries taking longer. © 2015 The Author(s).

Tanner-Whitehouse Skeletal Ages in Male Youth Soccer Players: TW2 or TW3?

PubMed

Malina, Robert M; Coelho-E-Silva, Manuel J; Figueiredo, António J; Philippaerts, Renaat M; Hirose, Norikazu; Peña Reyes, Maria Eugenia; Gilli, Giulio; Benso, Andrea; Vaeyens, Roel; Deprez, Dieter; Guglielmo, Luiz F; Buranarugsa, Rojapon

2018-04-01

The Tanner-Whitehouse radius-ulna-short bone protocol (TW2 RUS) for the assessment of skeletal age (SA) is widely used to estimate the biological (skeletal) maturity status of children and adolescents. The scale for converting TW RUS ratings to an SA has been revised (TW3 RUS) and has implications for studies of youth athletes in age-group sports. The aim of this study was to compare TW2 and TW3 RUS SAs in an international sample of male youth soccer players and to compare distributions of players by maturity status defined by each SA protocol. SA assessments with the TW RUS method were collated for 1831 male soccer players aged 11-17 years from eight countries. RUS scores were converted to TW2 and TW3 SAs using the appropriate tables. SAs were related to chronological age (CA) in individual athletes and compared by CA groups. The difference of SA minus CA with TW2 SA and with TW3 SA was used to classify players as late, average, or early maturing with each method. Concordance of maturity classifications was evaluated with Cohen's Kappa coefficients. For the same RUS score, TW3 SAs were systematically and substantially reduced compared with TW2 SAs; mean differences by CA group ranged from - 0.97 to - 1.16 years. Kappa coefficients indicated at best fair concordance of TW2 and TW3 maturity classifications. Across the age range, 42% of players classified as average with TW2 SA were classified as late with TW3 SA, and 64% of players classified as early with TW2 SA were classified as average with TW3 SA. TW3 SAs were systematically lower than corresponding TW2 SAs in male youth soccer players. The differences between scales have major implications for the classification of players by maturity status, which is central to some talent development programs.

Activity profiles in U17, U20 and senior women's Brazilian National soccer teams during international competitions: Are there meaningful differences?

PubMed

Ramos, Guilherme P; Nakamura, Fábio Y; Penna, Eduardo M; Wilke, Carolina Franco; Pereira, Lucas A; Loturco, Irineu; Capelli, Luciano; Mahseredjian, Fábio; Silami-Garcia, Emerson; Coimbra, Cândido C

2017-07-31

The aim of this study was to compare locomotor activity profiles of Brazilian top-class female soccer players competing at distinct age brackets (U17, U20, and Senior). External match load of 14 U17, 14 U20, and 17 Senior female soccer players competing in 6-7 full official international matches were assessed using global positioning systems (GPS). Total distance covered, distance covered in high intensity (HID:15.6-20 kmh), distance covered in sprints (sprint:>20 kmh), number of accelerations (Acc)>1 ms, decelerations (Dec) >-1 ms, and Player Load generally increased across the age brackets (U17

Maximal Sprinting Speed of Elite Soccer Players During Training and Matches.

PubMed

Djaoui, Leo; Chamari, Karim; Owen, Adam L; Dellal, Alexandre

2017-06-01

The aim of the present study was to compare (a) the maximal sprinting speed (MSS) attained by soccer players during matches (MSSmatch) according to their level of play (professional first French division vs. elite amateur fourth French division) and the playing positions and (b) the MSS attained by professional soccer players during 14 different types of small-sided games (SSG, MSSSSG) and match-play. All players monitored through the study performed a 40-m sprint test to assess individual MSS (MSStest) and compare it to the training and match activity, with the calculation of the percentage of MSStest (%MSStest) reached. No differences were found according to the level of play; however, positional wide players achieved a higher MSSmatch, %MSStest, and MSSSSG than central players (both defenders and midfielders) during matches and SSG. MSSmatch were higher than all MSSSSG, and MSSSSG were positively correlated with the area of the pitch (0.45, p < 0.001), its length (0.53, p < 0.001), and the number of players involved (0.38, p < 0.001). The closer SSG was to match situation in terms of rules, the higher the MSSSSG. Wide players reached higher MSS in match and SSG than central players, confirming the relevance of using SSG close to match situation to specifically prepare elite players to the maximal running speed demand of the match.

Encouraging spontaneous synchronisation with D-Jogger, an adaptive music player that aligns movement and music.

PubMed

Moens, Bart; Muller, Chris; van Noorden, Leon; Franěk, Marek; Celie, Bert; Boone, Jan; Bourgois, Jan; Leman, Marc

2014-01-01

In this study we explore how music can entrain human walkers to synchronise to the musical beat without being instructed to do so. For this, we use an interactive music player, called D-Jogger, that senses the user's walking tempo and phase. D-Jogger aligns the music by manipulating the timing difference between beats and footfalls. Experiments are reported that led to the development and optimisation of four alignment strategies. The first strategy matched the music's tempo continuously to the runner's pace. The second strategy matched the music's tempo at the beginning of a song to the runner's pace, keeping the tempo constant for the remainder of the song. The third alignment starts a song in perfect phase synchrony and continues to adjust the tempo to match the runner's pace. The fourth and last strategy additionally adjusts the phase of the music so each beat matches a footfall. The first two strategies resulted in a minor increase of steps in phase synchrony with the main beat when compared to a random playlist, the last two strategies resulted in a strong increase in synchronised steps. These results may be explained in terms of phase-error correction mechanisms and motor prediction schemes. Finding the phase-lock is difficult due to fluctuations in the interaction, whereas strategies that automatically align the phase between movement and music solve the problem of finding the phase-locking. Moreover, the data show that once the phase-lock is found, alignment can be easily maintained, suggesting that less entrainment effort is needed to keep the phase-lock, than to find the phase-lock. The different alignment strategies of D-Jogger can be applied in different domains such as sports, physical rehabilitation and assistive technologies for movement performance.

Encouraging Spontaneous Synchronisation with D-Jogger, an Adaptive Music Player That Aligns Movement and Music

PubMed Central

Moens, Bart; Muller, Chris; van Noorden, Leon; Franěk, Marek; Celie, Bert; Boone, Jan; Bourgois, Jan; Leman, Marc

2014-01-01

In this study we explore how music can entrain human walkers to synchronise to the musical beat without being instructed to do so. For this, we use an interactive music player, called D-Jogger, that senses the user's walking tempo and phase. D-Jogger aligns the music by manipulating the timing difference between beats and footfalls. Experiments are reported that led to the development and optimisation of four alignment strategies. The first strategy matched the music's tempo continuously to the runner's pace. The second strategy matched the music's tempo at the beginning of a song to the runner's pace, keeping the tempo constant for the remainder of the song. The third alignment starts a song in perfect phase synchrony and continues to adjust the tempo to match the runner's pace. The fourth and last strategy additionally adjusts the phase of the music so each beat matches a footfall. The first two strategies resulted in a minor increase of steps in phase synchrony with the main beat when compared to a random playlist, the last two strategies resulted in a strong increase in synchronised steps. These results may be explained in terms of phase-error correction mechanisms and motor prediction schemes. Finding the phase-lock is difficult due to fluctuations in the interaction, whereas strategies that automatically align the phase between movement and music solve the problem of finding the phase-locking. Moreover, the data show that once the phase-lock is found, alignment can be easily maintained, suggesting that less entrainment effort is needed to keep the phase-lock, than to find the phase-lock. The different alignment strategies of D-Jogger can be applied in different domains such as sports, physical rehabilitation and assistive technologies for movement performance. PMID:25489742

Determination of Strength Exercise Intensities Based on the Load-Power-Velocity Relationship

PubMed Central

Jandačka, Daniel; Beremlijski, Petr

2011-01-01

The velocity of movement and applied load affect the production of mechanical power output and subsequently the extent of the adaptation stimulus in strength exercises. We do not know of any known function describing the relationship of power and velocity and load in the bench press exercise. The objective of the study is to find a function modeling of the relationship of relative velocity, relative load and mechanical power output for the bench press exercise and to determine the intensity zones of the exercise for specifically focused strength training of soccer players. Fifteen highly trained soccer players at the start of a competition period were studied. The subjects of study performed bench presses with the load of 0, 10, 30, 50, 70 and 90% of the predetermined one repetition maximum with maximum possible speed of movement. The mean measured power and velocity for each load (kg) were used to develop a multiple linear regression function which describes the quadratic relationship between the ratio of power (W) to maximum power (W) and the ratios of the load (kg) to one repetition maximum (kg) and the velocity (m•s−1) to maximal velocity (m•s−1). The quadratic function of two variables that modeled the searched relationship explained 74% of measured values in the acceleration phase and 75% of measured values from the entire extent of the positive power movement in the lift. The optimal load for reaching maximum power output suitable for the dynamics effort strength training was 40% of one repetition maximum, while the optimal mean velocity would be 75% of maximal velocity. Moreover, four zones: maximum power, maximum velocity, velocity-power and strength-power were determined on the basis of the regression function. PMID:23486484

Determination of strength exercise intensities based on the load-power-velocity relationship.

PubMed

Jandačka, Daniel; Beremlijski, Petr

2011-06-01

The velocity of movement and applied load affect the production of mechanical power output and subsequently the extent of the adaptation stimulus in strength exercises. We do not know of any known function describing the relationship of power and velocity and load in the bench press exercise. The objective of the study is to find a function modeling of the relationship of relative velocity, relative load and mechanical power output for the bench press exercise and to determine the intensity zones of the exercise for specifically focused strength training of soccer players. Fifteen highly trained soccer players at the start of a competition period were studied. The subjects of study performed bench presses with the load of 0, 10, 30, 50, 70 and 90% of the predetermined one repetition maximum with maximum possible speed of movement. The mean measured power and velocity for each load (kg) were used to develop a multiple linear regression function which describes the quadratic relationship between the ratio of power (W) to maximum power (W) and the ratios of the load (kg) to one repetition maximum (kg) and the velocity (m•s(-1)) to maximal velocity (m•s(-1)). The quadratic function of two variables that modeled the searched relationship explained 74% of measured values in the acceleration phase and 75% of measured values from the entire extent of the positive power movement in the lift. The optimal load for reaching maximum power output suitable for the dynamics effort strength training was 40% of one repetition maximum, while the optimal mean velocity would be 75% of maximal velocity. Moreover, four zones: maximum power, maximum velocity, velocity-power and strength-power were determined on the basis of the regression function.

Effect of Concussion on Performance of National Football League Players.

PubMed

Reams, Nicole; Hayward, Rodney A; Kutcher, Jeffrey S; Burke, James F

2017-09-01

Lingering neurologic injury after concussion may expose athletes to increased risk if return to play is premature. The authors explored whether on-field performance after concussion is a marker of lingering neurologic injury. Retrospective cohort study on 1882 skill-position players who played in the National Football League (NFL) during 2007-2010. Players with concussion based on the weekly injury report were compared with players with other head and neck injuries (controls) on measures of on-field performance using Football Outsiders' calculation of defense-adjusted yards above replacement (DYAR), a measure of a player's contribution controlling for game context. Changes in performance, relative to a player's baseline level of performance, were estimated before and after injury using fixed-effects models. The study included 140 concussed players and 57 controls. Players with concussion performed no better or worse than their baseline on return to play. However, a decline in DYAR relative to their prior performance was noted 2 wk and 1 wk before appearing on the injury report. Concussed players performed slightly better than controls in situations where they returned to play the same week as appearing on the injury report. On return, concussed NFL players performed at their baseline level of performance, suggesting that players have recovered from concussion. Decline in performance noted 2 wk and 1 wk before appearing on the injury report may suggest that concussion diagnosis was delayed or that concussion can be a multihit phenomenon. Athletic performance may be a novel tool for assessing concussion injury and recovery.

Anthropometric and performance comparisons in professional baseball players.

PubMed

Hoffman, Jay R; Vazquez, Jose; Pichardo, Napoleon; Tenenbaum, Gershon

2009-11-01

This study compared anthropometric and performance variables in professional baseball players and examined the relationship between these variables and baseball-specific performance (i.e., home runs, total bases, slugging percentage, and stolen bases). During a 2-year period, 343 professional baseball players were assessed for height, weight, body composition, grip strength, vertical jump power, 10-yard sprint speed, and agility. Subject population consisted of players on the rosters of one of the minor league affiliates (Rookie, A, AA, AAA) or major league team (MLB). All testing occurred at the beginning of spring training. Players in Rookie and A were significantly (p < 0.05) leaner than players in MLB and AAA. These same players had significantly lower lean body mass than seen in MLB, AAA, and AA players. Greater grip strength (p < 0.05) was seen in MLB and AAA than in Rookie and A. Players in MLB were also faster (p < 0.05) than players in AA, A, and Rookie. Vertical jump power measures were greater (p < 0.05) in MLB than AA, A, and Rookie. Regression analysis revealed that performance measures accounted for 25-31% of the variance in baseball-specific power performance. Anthropometric measures failed to add any additional explanation to the variance in these baseball-specific performance variables. Results indicated that both anthropometric and performance variables differed between players of different levels of competition in professional baseball. Agility, speed, and lower-body power appeared to provide the greatest predictive power of baseball-specific performance.

Cervical joint position sense in rugby players versus non-rugby players.

PubMed

Pinsault, Nicolas; Anxionnaz, Marion; Vuillerme, Nicolas

2010-05-01

To determine whether cervical joint position sense is modified by intensive rugby practice. A group-comparison study. University Medical Bioengineering Laboratory. Twenty young elite rugby players (10 forwards and 10 backs) and 10 young non-rugby elite sports players. Participants were asked to perform the cervicocephalic relocation test (CRT) to the neutral head position (NHP) that is, to reposition their head on their trunk, as accurately as possible, after full active left and right cervical rotation. Rugby players were asked to perform the CRT to NHP before and after a training session. Absolute and variable errors were used to assess accuracy and consistency of the repositioning for the three groups of Forwards, Backs and Non-rugby players, respectively. The 2 groups of Forwards and Backs exhibited higher absolute and variable errors than the group of Non-rugby players. No difference was found between the two groups of Forwards and Backs and no difference was found between Before and After the training session. The cervical joint position sense of young elite rugby players is altered compared to that of non-rugby players. Furthermore, Forwards and Backs demonstrated comparable repositioning errors before and after a specific training session, suggesting that cervical proprioceptive alteration is mainly due to tackling and not the scrum.

Copenhagen five-second squeeze: a valid indicator of sports-related hip and groin function.

PubMed

Thorborg, K; Branci, S; Nielsen, M P; Langelund, M T; Hölmich, P

2017-04-01

No simple clinical measure exits to evaluate groin pain and its severity in athletes. The aim was to investigate the validity, reliability and responsiveness of a five-second hip-adduction squeeze test for football players designed to assess sports-related hip and groin function, pain and severity. Construct validity was assessed in 667 subelite male football players with a mean age (±SD) of 24±4 in the beginning of the season. Responsiveness and reliability were evaluated during the season in 52 and 10 players, respectively. Players answered the Copenhagen Hip and Groin Outcome Score (HAGOS) and performed the Copenhagen five-second squeeze assessed on a Numerical Pain Rating Scale (NRS) ranging from 0 to 10. As hypothesised higher pain scores during the Copenhagen five-second squeeze correlated significantly (Spearman's rho=-0.61, p<0.01) with a lesser HAGOS (Sport) Score. The change scores in the Copenhagen five-second squeeze also correlated significantly (Spearman's rho=-0.51, p<0.01), with HAGOS (Sport) change scores in the responsiveness analysis, and test-retest reliability (concordance correlation coefficient) was 0.90. Moreover, significant (p<0.01) between-group differences existed for HAGOS (Sport) Scores in players reporting groin pain intensity at one of the 3 different pain levels: NRS (0-2), NRS (3-5) and NRS (6-10). The NRS (6-10) group had the lowest median (IQR) HAGOS (Sport) Score of 47 (31-61). The Copenhagen five-second squeeze is a valid indicator of sports-related hip and groin function in football players. Players reporting groin pain intensity as 6 of 10 or more in the Copenhagen five-second squeeze experience substantially impaired sports-related hip and groin function. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

The Prevalence of Selected Intrinsic Risk Factors for Ankle Sprain Among Elite Football and Basketball Players

PubMed Central

Halabchi, Farzin; Angoorani, Hooman; Mirshahi, Maryam; Pourgharib Shahi, Mohammad Hosein; Mansournia, Mohammad Ali

2016-01-01

Background Lateral ankle sprains (LAS) are among the most common sports- related injuries and the reinjury rate is very high. Objectives This study aimed to evaluate the prevalence of some intrinsic risk factors among professional football and basketball players with or without history of acute or recurrent ankle sprain. Patients and Methods One hundred and six professional football and basketball players who were referred for pre-participation examinations were recruited in this study. Prepared checklist was completed for each participant. Athletes were asked for any history of previous ankle sprain and the severity (based of self-description of signs and symptoms by the athlete), level and number of injuries in the last two years. All players were assessed for measures of foot posture index- 6, foot length and width, Beighton generalized joint laxity score, anterior drawer and talar tilt tests, star excursion and single leg balance tests and goniometric assessment of ankle plantarflexion, ankle dorsiflexion and first metatarsophalangeal dorsiflexion. Results Forty eight basketball players (45.3%) and 58 football players (54.7%) with mean (SD) age of 19.8 (4.5) years participated. About 58.5% and 14.2% of athletes had a history of ankle sprain and recurrent sprain in at least one extremity, respectively. Sprains were more prevalent in basketball players and in dominant leg. There was no significant difference in assessed risk factors between athletes with and without history of ankle sprain, except for positive single leg balance test which was more prevalent in athletes with history of ankle sprain and also for positive talar tilt test and decreased ankle plantarflexion range of motion in acute and recurrent injury of left ankle. Conclusions Some intrinsic risk factors including lateral ankle ligaments laxity, balance and ankle plantarflexion seem to be related to acute or recurrent LAS in athletes. Further research is needed to reveal the role of different arthrokinematics following lateral ankle sprain. PMID:27826402

Effect of proprioception training on knee joint position sense in female team handball players.

PubMed

Pánics, G; Tállay, A; Pavlik, A; Berkes, I

2008-06-01

A number of studies have shown that proprioception training can reduce the risk of injuries in pivoting sports, but the mechanism is not clearly understood. To determine the contributing effects of propioception on knee joint position sense among team handball players. Prospective cohort study. Two professional female handball teams were followed prospectively for the 2005-6 season. 20 players in the intervention team followed a prescribed proprioceptive training programme while 19 players in the control team did not have a specific propioceptive training programme. The coaches recorded all exposures of the individual players. The location and nature of injuries were recorded. Joint position sense (JPS) was measured by a goniometer on both knees in three angle intervals, testing each angle five times. Assessments were performed before and after the season by the same examiner for both teams. In the intervention team a third assessment was also performed during the season. Complete data were obtained for 15 subjects in the intervention team and 16 in the control team. Absolute error score, error of variation score and SEM were calculated and the results of the intervention and control teams were compared. The proprioception sensory function of the players in the intervention team was significantly improved between the assessments made at the start and the end of the season (mean (SD) absolute error 9.78-8.21 degrees (7.19-6.08 degrees ) vs 3.61-4.04 degrees (3.71-3.20 degrees ), p<0.05). No improvement was seen in the sensory function in the control team between the start and the end of the season (mean (SD) absolute error 6.31-6.22 degrees (6.12-3.59 degrees ) vs 6.13-6.69 degrees (7.46-6.49 degrees ), p>0.05). This is the first study to show that proprioception training improves the joint position sense in elite female handball players. This may explain the effect of neuromuscular training in reducing the injury rate.

Reliability and Validity of a Submaximal Warm-up Test for Monitoring Training Status in Professional Soccer Players.

PubMed

Rabbani, Alireza; Kargarfard, Mehdi; Twist, Craig

2018-02-01

Rabbani, A, Kargarfard, M, and Twist, C. Reliability and validity of a submaximal warm-up test for monitoring training status in professional soccer players. J Strength Cond Res 32(2): 326-333, 2018-Two studies were conducted to assess the reliability and validity of a submaximal warm-up test (SWT) in professional soccer players. For the reliability study, 12 male players performed an SWT over 3 trials, with 1 week between trials. For the validity study, 14 players of the same team performed an SWT and a 30-15 intermittent fitness test (30-15IFT) 7 days apart. Week-to-week reliability in selected heart rate (HR) responses (exercise heart rate [HRex], heart rate recovery [HRR] expressed as the number of beats recovered within 1 minute [HRR60s], and HRR expressed as the mean HR during 1 minute [HRpost1]) was determined using the intraclass correlation coefficient (ICC) and typical error of measurement expressed as coefficient of variation (CV). The relationships between HR measures derived from the SWT and the maximal speed reached at the 30-15IFT (VIFT) were used to assess validity. The range for ICC and CV values was 0.83-0.95 and 1.4-7.0% in all HR measures, respectively, with the HRex as the most reliable HR measure of the SWT. Inverse large (r = -0.50 and 90% confidence limits [CLs] [-0.78 to -0.06]) and very large (r = -0.76 and CL, -0.90 to -0.45) relationships were observed between HRex and HRpost1 with VIFT in relative (expressed as the % of maximal HR) measures, respectively. The SWT is a reliable and valid submaximal test to monitor high-intensity intermittent running fitness in professional soccer players. In addition, the test's short duration (5 minutes) and simplicity mean that it can be used regularly to assess training status in high-level soccer players.

Assessing personal talent determinants in young racquet sport players: a systematic review.

PubMed

Faber, Irene R; Bustin, Paul M J; Oosterveld, Frits G J; Elferink-Gemser, Marije T; Nijhuis-Van der Sanden, Maria W G

2016-01-01

Since junior performances have little predictive value for future success, other solutions are sought to assess a young player's potential. The objectives of this systematic review are (1) to provide an overview of instruments measuring personal talent determinants of young players in racquet sports, and (2) to evaluate these instruments regarding their validity for talent development. Electronic searches were conducted in PubMed, PsychINFO, Web of Knowledge, ScienceDirect and SPORTDiscus (1990 to 31 March 2014). Search terms represented tennis, table tennis, badminton and squash, the concept of talent, methods of testing and children. Thirty articles with information regarding over 100 instruments were included. Validity evaluation showed that instruments focusing on intellectual and perceptual abilities, and coordinative skills discriminate elite from non-elite players and/or are related to current performance, but their predictive validity is not confirmed. There is moderate evidence that the assessments of mental and goal management skills predict future performance. Data on instruments measuring physical characteristics prohibit a conclusion due to conflicting findings. This systematic review yielded an ambiguous end point. The lack of longitudinal studies precludes verification of the instrument's capacity to forecast future performance. Future research should focus on instruments assessing multidimensional talent determinants and their predictive value in longitudinal designs.

Talent identification and selection in elite youth football: An Australian context.

PubMed

O'Connor, Donna; Larkin, Paul; Mark Williams, A

2016-10-01

We identified the perceptual-cognitive skills and player history variables that differentiate players selected or not selected into an elite youth football (i.e. soccer) programme in Australia. A sample of elite youth male football players (n = 127) completed an adapted participation history questionnaire and video-based assessments of perceptual-cognitive skills. Following data collection, 22 of these players were offered a full-time scholarship for enrolment at an elite player residential programme. Participants selected for the scholarship programme recorded superior performance on the combined perceptual-cognitive skills tests compared to the non-selected group. There were no significant between group differences on the player history variables. Stepwise discriminant function analysis identified four predictor variables that resulted in the best categorization of selected and non-selected players (i.e. recent match-play performance, region, number of other sports participated, combined perceptual-cognitive performance). The effectiveness of the discriminant function is reflected by 93.7% of players being correctly classified, with the four variables accounting for 57.6% of the variance. Our discriminating model for selection may provide a greater understanding of the factors that influence elite youth talent selection and identification.

Monitoring Elite Soccer Players' External Loads Using Real-Time Data.

PubMed

Barrett, Steve

2017-11-01

To assess the validity of measuring locomotor activities and PlayerLoad using real-time (RT) data collection during soccer training. Twenty-nine English soccer players participated. Each player wore the same MEMS device (Micromechanical Electrical Systems; S5, Optimeye; CatapultSports, Melbourne, Australia) during 21 training sessions (N = 331 data sets) in the 2015-16 and 2016-17 seasons. An RT receiver (TRX; Catapultsports, Melbourne, Australia) was used to collect the locomotor activities and PlayerLoad data in RT and compared with the postevent downloaded (PED) data. PlayerLoad and locomotor activities (total distance covered; total high-speed running distance covered, >5.5#x00A0;m/s; total sprinting distance covered, >7 m/s; maximum velocity) were analyzed. Correlations were near perfect for all variables analyzed (r = .98-1.00), with a varied level of noise between RT and PED also (0.3-9.7% coefficient of variation). Locomotor activities and PlayerLoad can use both RT and PED concurrently to quantify a player's physical output during a training session. Caution should be taken with higher-velocity-based locomotor activities during RT compared to PED.

Training strategy of explosive strength in young female volleyball players.

PubMed

Pereira, Ana; Costa, Aldo M; Santos, Patricia; Figueiredo, Teresa; João, Paulo Vicente

2015-01-01

The aim of this study was to examine the effect of an 8-week combined jump and ball throwing training program in the performance of upper and lower extremities among young female volleyball players of the high school. A total of 20 young female volleyball players playing at Scholar Sport in High School at the district level were divided in two groups: the experimental group (n=10; 14.0±0.0 years; 1.6±0.1 m; 52.0±7.0 kg and 20.7±2.4% body mass) and the control group (n=10; 13.8±0.4 years, 1.6±0.1 m; 53.5±4.7 kg and 20.3±1.7% body mass). The experimental group received additional plyometric and ball throwing exercises besides their normal volleyball practice. The control group underwent only their regular session of training. Strength performance in the experimental group significantly improved (medicine ball and volleyball ball throwing: P=0.00; and counter movement jump: P=0.05), with the improvement ranging from 5.3% to 20.1%. No significant changes in strength performance were observed in the control group (P>0.05). The 8-week combined jump and ball throwing training can significantly improve muscular performance in young female volleyball players. These findings may be useful for all physical education teachers and volleyball coaches. Copyright © 2015 Lithuanian University of Health Sciences. Production and hosting by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Assessing worst case scenarios in movement demands derived from global positioning systems during international rugby union matches: Rolling averages versus fixed length epochs

PubMed Central

Cunningham, Daniel J.; Shearer, David A.; Carter, Neil; Drawer, Scott; Pollard, Ben; Bennett, Mark; Eager, Robin; Cook, Christian J.; Farrell, John; Russell, Mark

2018-01-01

The assessment of competitive movement demands in team sports has traditionally relied upon global positioning system (GPS) analyses presented as fixed-time epochs (e.g., 5–40 min). More recently, presenting game data as a rolling average has become prevalent due to concerns over a loss of sampling resolution associated with the windowing of data over fixed periods. Accordingly, this study compared rolling average (ROLL) and fixed-time (FIXED) epochs for quantifying the peak movement demands of international rugby union match-play as a function of playing position. Elite players from three different squads (n = 119) were monitored using 10 Hz GPS during 36 matches played in the 2014–2017 seasons. Players categorised broadly as forwards and backs, and then by positional sub-group (FR: front row, SR: second row, BR: back row, HB: half back, MF: midfield, B3: back three) were monitored during match-play for peak values of high-speed running (>5 m·s-1; HSR) and relative distance covered (m·min-1) over 60–300 s using two types of sample-epoch (ROLL, FIXED). Irrespective of the method used, as the epoch length increased, values for the intensity of running actions decreased (e.g., For the backs using the ROLL method, distance covered decreased from 177.4 ± 20.6 m·min-1 in the 60 s epoch to 107.5 ± 13.3 m·min-1 for the 300 s epoch). For the team as a whole, and irrespective of position, estimates of fixed effects indicated significant between-method differences across all time-points for both relative distance covered and HSR. Movement demands were underestimated consistently by FIXED versus ROLL with differences being most pronounced using 60 s epochs (95% CI HSR: -6.05 to -4.70 m·min-1, 95% CI distance: -18.45 to -16.43 m·min-1). For all HSR time epochs except one, all backs groups increased more (p < 0.01) from FIXED to ROLL than the forward groups. Linear mixed modelling of ROLL data highlighted that for HSR (except 60 s epoch), SR was the only group not significantly different to FR. For relative distance covered all other position groups were greater than the FR (p < 0.05). The FIXED method underestimated both relative distance (~11%) and HSR values (up to ~20%) compared to the ROLL method. These differences were exaggerated for the HSR variable in the backs position who covered the greatest HSR distance; highlighting important consideration for those implementing the FIXED method of analysis. The data provides coaches with a worst-case scenario reference on the running demands required for periods of 60–300 s in length. This information offers novel insight into game demands and can be used to inform the design of training games to increase specificity of preparation for the most demanding phases of matches. PMID:29621279

Soccer-Specific Warm-Up and Lower Extremity Injury Rates in Collegiate Male Soccer Players

PubMed Central

Grooms, Dustin R.; Palmer, Thomas; Onate, James A.; Myer, Gregory D.; Grindstaff, Terry

2013-01-01

Context: A number of comprehensive injury-prevention programs have demonstrated injury risk-reduction effects but have had limited adoption across athletic settings. This may be due to program noncompliance, minimal exercise supervision, lack of exercise progression, and sport specificity. A soccer-specific program described as the F-MARC 11+ was developed by an expert group in association with the Federation Internationale de Football Association (FIFA) Medical Assessment and Research Centre (F-MARC) to require minimal equipment and implementation as part of regular soccer training. The F-MARC 11+ has been shown to reduce injury risk in youth female soccer players but has not been evaluated in an American male collegiate population. Objective: To investigate the effects of a soccer-specific warm-up program (F-MARC 11+) on lower extremity injury incidence in male collegiate soccer players. Design: Cohort study. Setting: One American collegiate soccer team followed for 2 seasons. Patients or Other Participants: Forty-one male collegiate athletes aged 18–25 years. Intervention(s): The F-MARC 11+ program is a comprehensive warm-up program targeting muscular strength, body kinesthetic awareness, and neuromuscular control during static and dynamic movements. Training sessions and program progression were monitored by a certified athletic trainer. Main Outcome Measure(s): Lower extremity injury risk and time lost to lower extremity injury. Results: The injury rate in the referent season was 8.1 injuries per 1000 exposures with 291 days lost and 2.2 injuries per 1000 exposures and 52 days lost in the intervention season. The intervention season had reductions in the relative risk (RR) of lower extremity injury of 72% (RR = 0.28, 95% confidence interval = 0.09, 0.85) and time lost to lower extremity injury (P < .01). Conclusions: This F-MARC 11+ program reduced overall risk and severity of lower extremity injury compared with controls in collegiate-aged male soccer athletes. PMID:23848519

A comparison of the technique of the football quarterback pass between high school and university athletes.

PubMed

Toffan, Adam; Alexander, Marion J L; Peeler, Jason

2017-07-28

The purpose of the study was to compare the most effective joint movements, segment velocities and body positions to perform the fastest and most accurate pass of high school and university football quarterbacks. Secondary purposes were to develop a quarterback throwing test to assess skill level, to determine which kinematic variables were different between high school and university athletes as well as to determine which variables were significant predictors of quarterback throwing test performance. Ten high school and ten university athletes were filmed for the study, performing nine passes at a target and two passes for maximum distance. Thirty variables were measured using Dartfish Team Pro 4.5.2 video analysis system, and Microsoft Excel was used for statistical analysis. University athletes scored slightly higher than the high school athletes on the throwing test, however this result was not statistically significant. Correlation analysis and forward stepwise multiple regression analysis was performed on both the high school players and the university players in order to determine which variables were significant predictors of throwing test score. Ball velocity was determined to have the strongest predictive effect on throwing test score (r = 0.900) for the high school athletes, however, position of the back foot at release was also determined to be important (r = 0.661) for the university group. Several significant differences in throwing technique between groups were noted during the pass, however, body position at release showed the greatest differences between the two groups. High school players could benefit from more complete weight transfer and decreased throw time to increase throwing test score. University athletes could benefit from increased throw time and greater range of motion in external shoulder rotation and trunk rotation to increase their throwing test score. Coaches and practitioners will be able to use the findings of this research to help improve these and related throwing variables in their high school and university quarterbacks.

Validity, Reliability, and Sensitivity of a Volleyball Intermittent Endurance Test.

PubMed

Rodríguez-Marroyo, Jose A; Medina-Carrillo, Javier; García-López, Juan; Morante, Juan C; Villa, José G; Foster, Carl

2017-03-01

To analyze the concurrent and construct validity of a volleyball intermittent endurance test (VIET). The VIET's test-retest reliability and sensitivity to assess seasonal changes was also studied. During the preseason, 71 volleyball players of different competitive levels took part in this study. All performed the VIET and a graded treadmill test with gas-exchange measurement (GXT). Thirty-one of the players performed an additional VIET to analyze the test-retest reliability. To test the VIET's sensitivity, 28 players repeated the VIET and GXT at the end of their season. Significant (P < .001) relationships between VIET distance and maximal oxygen uptake (r = .74) and GXT maximal speed (r = .78) were observed. There were no significant differences between the VIET performance test and retest (1542.1 ± 338.1 vs 1567.1 ± 358.2 m). Significant (P < .001) relationships and intraclass correlation coefficient (ICC) were found (r = .95, ICC = .96) for VIET performance. VIET performance increased significantly (P < .001) with player performance level and was sensitive to fitness changes across the season (1458.8 ± 343.5 vs 1581.1 ± 334.0 m, P < .01). The VIET may be considered a valid, reliable, and sensitive test to assess the aerobic endurance in volleyball players.

Unilateral jumps in different directions: a novel assessment of soccer-associated power?

PubMed

Murtagh, Conall F; Vanrenterghem, Jos; O'Boyle, Andrew; Morgans, Ryland; Drust, Barry; Erskine, Robert M

2017-11-01

We aimed to determine whether countermovement jumps (CMJs; unilateral and bilateral) performed in different directions assessed independent lower-limb power qualities, and if unilateral CMJs would better differentiate between elite and non-elite soccer players than the bilateral vertical (BV) CMJ. Elite (n=23; age, 18.1±1.0years) and non-elite (n=20; age, 22.3±2.7years) soccer players performed three BV, unilateral vertical (UV), unilateral horizontal-forward (UH) and unilateral medial (UM) CMJs. Jump performance (height and projectile range), kinetic and kinematic variables from ground reaction forces, and peak activation levels of the vastus lateralis and biceps femoris (BF) muscles from surface electromyography, were compared between jumps and groups of players. Peak vertical power (V-power) was greater in BV (220.2±30.1W/kg) compared to UV (144.1±16.2W/kg), which was greater than UH (86.7±18.3W/kg) and UM (85.5±13.5W/kg) (all, p<0.05) but there was no difference between UH and UM (p=1.000). Peak BF EMG was greater in UH compared to all other CMJs (p≤0.001). V-power was greater in elite than non-elite for all CMJs (p≤0.032) except for BV (p=0.197). Elite achieved greater UH projectile range than non-elite (51.6±15.4 vs. 40.4±10.4cm, p=0.009). We have shown that UH, UV and UM CMJs assess distinct lower-limb muscular power capabilities in soccer players. Furthermore, as elite players outperformed non-elite players during unilateral but not BV CMJs, unilateral CMJs in different directions should be included in soccer-specific muscular power assessment and talent identification protocols, rather than the BV CMJ. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

The Diet Quality of Competitive Adolescent Male Rugby Union Players with Energy Balance Estimated Using Different Physical Activity Coefficients

PubMed Central

Burrows, Tracy; Harries, Simon K.; Williams, Rebecca L.; Lum, Cheryl; Callister, Robin

2016-01-01

Objectives: The aims of the current study were to comprehensively assess the dietary intakes and diet quality of a sample of Australian competitive adolescent rugby union players and compare these intakes with National and Sports Dietitians Association (SDA) Recommendations for adolescent athletes. A secondary aim investigated applying different physical activity level (PAL) coefficients to determine total energy expenditure (TEE) in order to more effectively evaluate the adequacy of energy intakes. Design: Cross-sectional. Methods: Anthropometrics and dietary intakes were assessed in 25 competitive adolescent male rugby union players (14 to 18 years old). Diet was assessed using the validated Australian Eating Survey (AES) food frequency questionnaire and diet quality was assessed through the Australian Recommended Food Score. Results: The median dietary intakes of participants met national recommendations for percent energy (% E) from carbohydrate, protein and total fat, but not carbohydrate intake when evaluated as g/day as proposed in SDA guidelines. Median intakes of fibre and micronutrients including calcium and iron also met national recommendations. Overall diet quality was classified as ‘good’ with a median diet quality score of 34 (out of a possible 73); however, there was a lack of variety within key food groups including carbohydrates and proteins. Non-core food consumption exceeded recommended levels at 38% of the daily total energy intake, with substantial contributions from takeaway foods and sweetened beverages. A PAL coefficient of 1.2–1.4 was found to best balance the energy intakes of these players in their pre-season. Conclusions: Adolescent rugby players met the percent energy recommendations for macronutrients and attained an overall ‘good’ diet quality score. However, it was identified that when compared to specific recommendations for athletes, carbohydrate intakes were below recommendations and these players in their pre-season reported high consumption of non-core foods, particularly sugar sweetened drinks and low intakes of vegetables. PMID:27618089

The Diet Quality of Competitive Adolescent Male Rugby Union Players with Energy Balance Estimated Using Different Physical Activity Coefficients.

PubMed

Burrows, Tracy; Harries, Simon K; Williams, Rebecca L; Lum, Cheryl; Callister, Robin

2016-09-07

The aims of the current study were to comprehensively assess the dietary intakes and diet quality of a sample of Australian competitive adolescent rugby union players and compare these intakes with National and Sports Dietitians Association (SDA) Recommendations for adolescent athletes. A secondary aim investigated applying different physical activity level (PAL) coefficients to determine total energy expenditure (TEE) in order to more effectively evaluate the adequacy of energy intakes. Cross-sectional. Anthropometrics and dietary intakes were assessed in 25 competitive adolescent male rugby union players (14 to 18 years old). Diet was assessed using the validated Australian Eating Survey (AES) food frequency questionnaire and diet quality was assessed through the Australian Recommended Food Score. The median dietary intakes of participants met national recommendations for percent energy (% E) from carbohydrate, protein and total fat, but not carbohydrate intake when evaluated as g/day as proposed in SDA guidelines. Median intakes of fibre and micronutrients including calcium and iron also met national recommendations. Overall diet quality was classified as 'good' with a median diet quality score of 34 (out of a possible 73); however, there was a lack of variety within key food groups including carbohydrates and proteins. Non-core food consumption exceeded recommended levels at 38% of the daily total energy intake, with substantial contributions from takeaway foods and sweetened beverages. A PAL coefficient of 1.2-1.4 was found to best balance the energy intakes of these players in their pre-season. Adolescent rugby players met the percent energy recommendations for macronutrients and attained an overall 'good' diet quality score. However, it was identified that when compared to specific recommendations for athletes, carbohydrate intakes were below recommendations and these players in their pre-season reported high consumption of non-core foods, particularly sugar sweetened drinks and low intakes of vegetables.

Human Pacman: A Mobile Augmented Reality Entertainment System Based on Physical, Social, and Ubiquitous Computing

NASA Astrophysics Data System (ADS)

Cheok, Adrian David

This chapter details the Human Pacman system to illuminate entertainment computing which ventures to embed the natural physical world seamlessly with a fantasy virtual playground by capitalizing on infrastructure provided by mobile computing, wireless LAN, and ubiquitous computing. With Human Pacman, we have a physical role-playing computer fantasy together with real human-social and mobile-gaming that emphasizes on collaboration and competition between players in a wide outdoor physical area that allows natural wide-area human-physical movements. Pacmen and Ghosts are now real human players in the real world experiencing mixed computer graphics fantasy-reality provided by using the wearable computers on them. Virtual cookies and actual tangible physical objects are incorporated into the game play to provide novel experiences of seamless transitions between the real and virtual worlds. This is an example of a new form of gaming that anchors on physicality, mobility, social interaction, and ubiquitous computing.

Effect of progressive resistance exercise with neuromuscular joint facilitation on the dynamic balance performance of junior soccer players.

PubMed

Wang, Hongzhao; Huo, Ming; Guan, Peipei; Onoda, Ko; Chen, Di; Huang, Qiuchen; Maruyama, Hitoshi

2015-11-01

[Purpose] The aim of this study was to investigate the change in dynamic balance performance of junior soccer players after progressive resistance treatment with neuromuscular joint facilitation (NJF). [Subjects] The subjects were 14 healthy males who were divided into two groups, namely the NJF and control groups. The NJF group consisted of 8 subjects, and the control group consisted of 6 subjects. [Methods] The participants in the NJF group received NJF progressive resistance treatment. Dynamic balance performance was measured before and after 3 weeks of exercise. [Results] Significant improvement in dynamic balance performance was observed both in the NJF and control groups. In the NJF group, dynamic balance performance was significantly increased compared with that in the control group. [Conclusion] The NJF intervention shortened movement time, which implies that NJF is effective for dynamic balance performance.

Comparison of plantar pressure distribution between three different shoes and three common movements in futsal.

PubMed

Teymouri, Meghdad; Halabchi, Farzin; Mirshahi, Maryam; Mansournia, Mohammad Ali; Mousavi Ahranjani, Ali; Sadeghi, Amir

2017-01-01

Analysis of in-shoe pressure distribution during sport-specific movements may provide a clue to improve shoe design and prevent injuries. This study compared the mean and the peak pressures over the whole foot and ten separate areas of the foot, wearing different shoes during specific movements. Nine male adult recreational futsal players performed three trials of three sport-specific movements (shuffle, sprint and penalty kick), while they were wearing three brands of futsal shoes (Adidas, Lotto and Tiger). Plantar pressures on dominant feet were collected using the F-SCAN system. Peak and mean pressures for whole foot and each separate area were extracted. For statistical analysis, the mean differences in outcome variables between different shoes and movements were estimated using random-effects regression model using STATA ver.10. In the average calculation of the three movements, the peak pressure on the whole foot in Adidas shoe was less than Lotto [8.8% (CI95%: 4.1-13.6%)] and Tiger shoes [11.8% (CI95%:7-16.7%)], (P<0.001). Also, the recorded peak pressure on the whole foot in penalty kick was 61.1% (CI95%: 56.3-65.9%) and 57.6% (CI95%: 52.8-62.3%) less than Shuffle and Sprint tests, respectively (P<0.001). Areas with the highest peak pressure during all 3 movements were not different between all shoes. This area was medial forefoot in cases of shuffle and sprint movements and medial heel in case of penalty kick.