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Sample records for adolescent volleyball players

  1. 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

  2. Menstrual cycle disorders in female volleyball players.

    PubMed

    Wodarska, M; Witkoś, J; Drosdzol-Cop, A; Dąbrowska, J; Dąbrowska-Galas, M; Hartman, M; Plinta, R; Skrzypulec-Plinta, V

    2013-07-01

    The aim of this study was to examine the relation between increased physical activity and menstrual disorders in adolescent female volleyball players. The study was conducted on 210 Polish female volleyball players, aged 13-17 years, the authorship questionnaire was used. The results of the study showed that irregular menstruation occurred in 19% of girls, spotting between menstrual periods in 27% and heavy menstruation was reported in 33% of girls. Out of all volleyball female players participating in the study, 94 girls (45%) declared absence of menstrual periods after regular cycles. Statistical analysis showed that the more training hours per week, the bigger probability of the occurrence of irregular menstruation. It was concluded that the number of hours of volleyball training per week affects regularity of menstrual cycles in female volleyball players. The absence of menstruation might be caused by the duration of training per week or years of training.

  3. Eating behaviors, nutritional status, and menstrual function in elite female adolescent volleyball players.

    PubMed

    Beals, Katherine A

    2002-09-01

    Nutritional status, eating behaviors and menstrual function was examined in 23 nationally ranked female adolescent volleyball players using a health/weight/ dieting/menstrual history questionnaire, the Eating Disorder Inventory (EDI), and the Body Shape Questionnaire (BSQ). Nutrient and energy intakes (El) and energy expenditure (EE) were determined by 3-d weighed food records and activity logs. Iron (Fe), vitamins C, B12, and Folate status were assessed using serum and whole blood. Mean El (2248 +/- 414 kcal/d) was less than EE (2815 +/- 306 kcal/d). Mean carbohydrate (5.4 +/-1.0g/kg/d) and protein (1.1+/-0.3g/kg/d) intakes were below recommended levels for highly active women. Mean intakes for folate, Fe, Ca, Mg, and Zn were less than the respective RDAs/DRIs and almost 50% of the athletes were consuming less than the RDAs/DRIs for the B-complex vitamins and vitamin C. Three athletes presented with Fe deficiency anemia (Hb <12 mg/dL), while marginal vitamin B12 status (<200 pg/ml) and vitamin C status (<28 mmol/L) were found in 1 and 4 athletes, respectively. Approximately 1/2 of the athletes reported actively "dieting". Mean BSQ and EDI subscales scores were within the normal ranges; yet, elevated scores on these scales were reported by 26% and 35% of athletes, respectively. Past or present amenorrhea was reported by 17% of the athletes and 13% and 48%, reported past or present oligomenorrhea and "irregular" menstrual cycles, respectively. These results indicate that elite adolescent volleyball players are at risk for menstrual dysfunction and have energy and nutrient intakes that place them at risk for nutritional deficiencies and compromised performance.

  4. Training increases anabolic response and reduces inflammatory response to a single practice in elite male adolescent volleyball players.

    PubMed

    Nemet, Dan; Portal, Shawn; Zadik, Zvi; Pilz-Burstein, Rutie; Adler-Portal, Dana; Meckel, Yoav; Eliakim, Alon

    2012-01-01

    We examined the effect of training on hormonal and inflammatory response to a single volleyball practice in elite adolescent players. Fourteen male, elite, national team-level, Israeli volleyball players (age, 16.3±1.1 years, Tanner stage 4-5) participated in the study. Blood samples were collected before and immediately after a typical 60-min volleyball practice, before and after 7 weeks of training during the initial phases of the volleyball season. Hormonal measurements included the anabolic hormones growth hormone (GH), insulin-like growth factor 1 (IGF-1), IGF-binding protein 3, and testosterone; the catabolic hormone cortisol; the pro-inflammatory markers interleukin (IL) 6, and the anti-inflammatory marker IL-1 receptor antagonist. Training led to a significant improvement of both anaerobic and aerobic properties. Before the training intervention, the typical volleyball practice was associated with a significant increase of GH and testosterone and also with a significant increase of IL-6. Training resulted in a significantly greater GH response (ΔGH, 2.5±2.4 vs. 4.7±3.0 ng/mL, before and after training, respectively; p<0.02) and reduced IL-6 response (ΔIL-6, 2.0±1.6 vs. 0.6±0.7 pg/mL, before and after training, respectively; p<0.01) to the same relative intensity volleyball practice. The results suggest that, along with the improvement of anaerobic and aerobic characteristics, training leads to a greater anabolic and reduced inflammatory response to exercise.

  5. Body mass index and body fat percentage are associated with decreased physical fitness in adolescent and adult female volleyball players

    PubMed Central

    Nikolaidis, Pantelis Theo

    2013-01-01

    Background: The objectives of this study were to examine (a) the prevalence of overweight/obesity, and (b) the relationship between body mass index (BMI), body fat percentage (BF) and physical fitness in adolescent and adult female volleyball players. Materials and Methods: Adolescent (n = 102, aged 15.2 ± 2.0 year) and adult (n = 57, 25.9 ± 5.0 year) players were examined for anthropometric characteristics and body composition, and performed the physical working capacity in heart rate 170 min-1 test, a force-velocity test, the Wingate anaerobic test (WAnT), sit-and-reach test (SAR), handgrip strength test (HST) and countermovement vertical jump (CVJ). Results: Based on international BMI cut-off points, 27.5% (n = 28) of adolescent and 12.3% (n = 7) of adult participants were classified as overweight, with the prevalence of overweight being higher in girls than in women (χ2 = 4.90, P = 0.027). BMI was correlated with BF in both age groups (r = 0.72, P < 0.001 in girls; r = 0.75, P < 0.001 in women). Normal participants had superior certain physical and physiological characteristics than those who were overweight. For instance, normal girls and women had higher mean power during WAnT than their overweight counterparts (P = 0.003 and P = 0.009 respectively). Except for flexibility, BMI and BF were inversely related with physical fitness (e.g., BMI vs. HST r = -0.39, P < 0.001 in girls; BF vs. CVJ r = -0.45, P < 0.001 in women). Conclusion: The findings confirmed the negative effect of overweight and fatness on selected parameters of physical fitness. The prevalence of overweight in adolescent volleyball players was higher than in general population, which was a novel finding, suggesting that proper exercise interventions should be developed to target the excess of body mass in youth volleyball clubs. PMID:23900100

  6. The Effect of Specific Sling Exercises on the Functional Movement Screen Score in Adolescent Volleyball Players: A Preliminary Study

    PubMed Central

    Saulicz, Edward; Myśliwiec, Andrzej; Wójtowicz, Monika; Wolny, Tomasz

    2016-01-01

    Abstract The existing data indicate that the result of the Functional Movement Screen (FMS) test influences the likelihood of subsequent injury in professional athletes. Therefore, exercises increasing test scores of the FMS may be useful at various stages of sports activity. This study evaluated the effects of the NEURAC sling exercises method on the FMS test score in teenage volleyball players. The study was conducted on 15 volleyball players aged 14 years. The FMS test was performed three times interspersed with a two-month interval. Between the first and the second assessment, neither additional treatment nor training was applied, while between the second and the third assessment, the participants performed stabilisation exercises based on the NEURAC method. Training was carried out twice a week, for eight weeks. The analysis showed that between the first and the second measurement, no significant differences occurred. The use of specific sling exercises caused a significant improvement in FMS results (p ≤ 0.01) between the first and the third, as well as the second and the third measurement. The applied stabilisation exercises based on the NEURAC method positively influenced the FMS test result in male subjects practicing volleyball. Performance of such exercises also resulted in more than 90% of the subjects having a total FMS test score ≥ 17, which may be important in the prevention of injuries. The preliminary results indicate that this type of exercise should be included in a teenage volleyball training routine. PMID:28031760

  7. Strength Asymmetry of the Shoulders in Elite Volleyball Players

    PubMed Central

    Hadzic, Vedran; Sattler, Tine; Veselko, Matjaž; Markovic, Goran; Dervisevic, Edvin

    2014-01-01

    Context: Volleyball players are reported to have shoulder strength imbalances. Previous authors have primarily investigated small samples of male players at a single skill level, without considering playing position, and with inconsistent findings. Objective: To evaluate shoulder strength asymmetry and a history of shoulder injury in a large sample of professional volleyball players of both sexes across different playing positions and skill levels. Design: Descriptive laboratory study. Patients or Other Participants: A sample of 183 volleyball players (99 men, 84 women). Main Outcome Measure(s): We assessed shoulder internal-rotator and external-rotator concentric strength at 60°/s using an isokinetic dynamometer and dominant-nondominant differences in shoulder strength and strength ratios using repeated-measures analyses of variance. Peak torque was normalized for body mass and external-rotation/internal-rotation concentric strength. Results: Internal-rotation strength was asymmetric in favor of the dominant side in both sexes, regardless of previous shoulder injury status. Male volleyball players had a lower shoulder strength ratio on the dominant side, regardless of previous shoulder injury status. However, this finding was valid only when hand dominance was taken into account. Female volleyball players playing at a higher level (ie, first versus second division) were 3.43 times more likely to have an abnormal strength ratio. Playing position was not associated with an abnormal shoulder strength ratio or strength asymmetry. Conclusions: In male volleyball players, the external-rotation/internal-rotation strength ratio of the dominant shoulder was lower, regardless of playing position, skill level, or a previous shoulder injury. In female players, the ratio was less only in those at a higher skill level. Although speculative, these findings generally suggest that female volleyball players could have a lower risk of developing shoulder-related problems than male

  8. Somatotype, size and body composition of competitive female volleyball players.

    PubMed

    Malousaris, Grigoris G; Bergeles, Nikolaos K; Barzouka, Karolina G; Bayios, Ioannis A; Nassis, George P; Koskolou, Maria D

    2008-06-01

    The aim of this study was to describe the morphological characteristics of competitive female volleyball players. For this purpose, body weight and height, breadths and girths as well as skinfold thickness at various body sites were assessed in 163 elite female volleyball players (age: 23.8+/-4.7 years, years of playing: 11.5+/-4.2, hours of training per week: 11.9+/-2.9, means+/-S.D.). Seventy-nine of these players were from the A1 division and the rest from the A2 division of the Greek National League. Two-way ANOVA was used to compare the differences in these characteristics between competition level and playing position. Body height ranged from 161cm to 194cm, and the mean value (177.1+/-6.5cm) was not inferior to that of international players of similar calibre. Adiposity of these players (sum of 5 skinfolds: 51.8+/-10.2mm, percent body fat: 23.4+/-2.8) was higher than that reported in other studies in which, however, different methodology was used. Volleyball athletes of this study were mainly balanced endomorphs (3.4-2.7-2.9). The A1 division players were taller and slightly leaner with greater fat-free mass than their A2 counterparts. Significant differences were found among athletes of different playing positions which are interpreted by their varying roles and physical demands during a volleyball game. The volleyball players who play as opposites were the only subgroup of players differing between divisions; the A2 opposites had more body fat than A1 opposites. These data could be added in the international literature related to the anthropometric characteristics of competitive female volleyball players.

  9. Identification af explosive power factors as predictors of player quality in young female volleyball players.

    PubMed

    Grgantov, Zoran; Milić, Mirjana; Katić, Ratko

    2013-05-01

    With the purpose of determining the factor structure of explosive power, as well as the influence of each factor on situational efficiency, 56 young female volleyball players were tested using 14 tests for assessing nonspecific and specific explosive power. By factor analysis, 4 significant factors were isolated which explained the total of over 80% of the common variability in young female volleyball players. The first factor was defined as volleyball-specific jumping, the second factor as nonspecific jumping and sprinting, the third factor as throwing explosive power, while the fourth factor was interpreted as volleyball-specific throwing and spiking speed from the ground. Results obtained by regression analysis in the latent space of explosive power indicate that the identified factors are good predictors of player quality in young female volleyball players. The fourth factor defined as throwing and spiking speed from the ground had the largest influence on player quality, followed by volleyball-specific jumping and nonspecific jumping and sprinting, and to a much lesser extent, by throwing explosive power The results obtained in this age group bring to the fore the ability of spiking and serving a ball of high speed, which hinders the opponents from playing those balls in serve reception and field defence. This ability, combined with a high standing vertical jump reach and spike approach vertical jump reach (which is the basis of the 1st varimax factor) enables successful performance of all volleyball elements by which points are won in complex 1 (spike) and complex 2 (serve and block). Even though the 2nd factor (nonspecific jumping and sprinting) has a slightly smaller impact on situational efficiency in young players, this ability provides preconditions i.e. preparation for successful realisation of all volleyball elements, so greater attention must be paid to perfecting it in young female volleyball players.

  10. Long-term training adaptations in elite male volleyball players.

    PubMed

    Sheppard, Jeremy M; Newton, Robert U

    2012-08-01

    Several investigations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite-level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear. The purpose of this investigation was to examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players. Fourteen national team volleyball players (age, 23.0 ± 4.1 years; height, 1.98 ± 0.07 m; weight, 91.7 ± 7.9 kg) began and completed this study. Participants had all played international matches (representing Australia) before the examination time period and continued to do so during the international season. Anthropometry (stature, mass, and sum of 7 skinfolds), vertical jump measures (countermovement vertical jump; depth jump from 0.35 m, DJ; spike jump, SPJ, all including arm swing), and lower-body power (jump squat at body mass, and jump squat + 50% body weight, JS50) measures were tested before and at the conclusion of the investigation period. Significant (p < 0.05) improvements were observed in sum of 7 skinfolds, DJ, SPJ, and JS50 performance, with large magnitude changes (d > 0.70) in the sum of 7 skinfolds reduction, SPJ, and leg extensor power. This study has demonstrated that elite male volleyball players can improve leanness and power, which contribute to improvements in vertical jump.

  11. Tales of the Unexpected: Coping among Female Collegiate Volleyball Players

    ERIC Educational Resources Information Center

    Holt, Nicholas L.; Berg, Kylie-Joy; Tamminen, Katherine A.

    2007-01-01

    The purpose of this study was to examine patterns of appraisal, coping, and coping effectiveness in sport. Ten players from a collegiate female volleyball team were interviewed on two occasions, first in the week before a provincial final playoff tournament and in the week following the tournament. Data were transcribed verbatim and subjected to…

  12. VALIDITY OF THE STANDING SPIKE TEST AS A MONITORING PROTOCOL FOR FEMALE VOLLEYBALL PLAYERS

    PubMed Central

    Valadés, D.

    2012-01-01

    The purpose of this paper was: a) to provide reference values for the standing spike test for female volleyball players and b) to study whether the standing spike test is valid for assessing the theoretical differences between female volleyball players. The sample included 83 players from the first nine teams of the Spanish women's first volleyball division (52 Spanish players and 31 from other nationalities). The variables studied were the ball speed of the standing spike test, the age of the players, the player's role (outside hitter, opposite, middle-blocker, libero, or setter), height, and nationality of the players (Spanish or foreign). The results demonstrate the ranges for the standing spike among female performance volleyball players (70-82 km · h−1). The differences regarding nationality, player role, height, and age seem to indicate that the test is a valid instrument for monitoring the performance of female volleyball players. PMID:24868119

  13. Training reduces catabolic and inflammatory response to a single practice in female volleyball players.

    PubMed

    Eliakim, Alon; Portal, Shawn; Zadik, Zvi; Meckel, Yoav; Nemet, Dan

    2013-11-01

    We examined the effect of training on hormonal and inflammatory response to a single volleyball practice in elite adolescent players. Thirteen female, national team level, Israeli volleyball players (age 16.0 ± 1.4 years, Tanner stage 4-5) participated in the study. Blood samples were collected before and immediately after a typical 60 minutes of volleyball practice, before and after 7 weeks of training during the initial phase of the season. Training involved tactic and technical drills (20% of time), power and speed drills (25% of time), interval sessions (25% of time), endurance-type training (15% of time), and resistance training (15% of time). To achieve greater training responses, the study was performed during the early phase (first 7 weeks) of the volleyball season. Hormonal measurements included the anabolic hormones growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF-binding protein-3, the catabolic hormone cortisol, the proinflammatory marker interleukin-6 (IL-6), and the anti-inflammatory marker IL-1 receptor antagonist. Training led to a significant improvement of vertical jump, anaerobic properties (peak and mean power by the Wingate Anaerobic Test), and predicted VO2max (by the 20-m shuttle run). Volleyball practice, both before and after the training intervention, was associated with a significant increase of serum lactate, GH, and IL-6. Training resulted in a significantly reduced cortisol response ([INCREMENT]cortisol: 4.2 ± 13.7 vs. -4.4 ± 12.3 ng · ml, before and after training, respectively; p < 0.02), and IL-6 response ([INCREMENT]IL-6: 1.3 ± 1.0 vs. 0.3 ± 0.4 pg · ml, before and after training, respectively; p < 0.01) to the same relative intensity volleyball practice. The results suggest that along with the improvement of power and anaerobic and aerobic characteristics, training reduces the catabolic and inflammatory response to exercise.

  14. Physical and physiological attributes of female volleyball players--a review.

    PubMed

    Lidor, Ronnie; Ziv, Gal

    2010-07-01

    The main objective of this article was to review a series of studies (n = 31) on physical attributes, physiological attributes, and on-court performances of female volleyball players. Empirical and practical knowledge emerging from studies on training-related issues in volleyball, such as body mass, fat-free mass, aerobic profile, strength, and agility and speed, should be integrated and applied when planning annual training programs for volleyball players. Based on our review, it was found that (a) players of a higher skill level are taller, somewhat heavier, and have higher vertical jump values than players of a lower level; (b) the aerobic profile of female volleyball players is similar to that of female basketball players; (c) ballistic resistance training can increase vertical jump values in female volleyball players; and (d) preseason conditioning should be conducted to prevent fatigue and reduced performance at the beginning of the season. Among the research concerns discussed in the article are that there is a lack data for on-court performance and time-motion analysis in female volleyball players and that more experimental/manipulative studies are needed to examine the effectiveness of different training programs on physiological attributes of female volleyball players. Two practical implications are suggested for volleyball and strength and conditioning coaches: (a) functional and nonfunctional overreaching should be carefully monitored when planning strength and conditioning programs, and (b) volleyball programs should include ballistic-type training.

  15. Lower Limb Neuromuscular Asymmetry in Volleyball and Basketball Players

    PubMed Central

    Fort-Vanmeerhaeghe, Azahara; Gual, Gabriel; Romero-Rodriguez, Daniel; Unnitha, Viswanath

    2016-01-01

    Abstract The primary objective of the present study was to evaluate the agreement between the dominant leg (DL) (determined subjectively) and the stronger leg (SL) (determined via a functional test) in a group of basketball and volleyball players. The secondary objective was to calculate lower limb neuromuscular asymmetry when comparing the DL vs the non-dominant leg (NDL) and the SL vs the weaker (WL) leg in the whole group and when differentiating by sex. Seventy-nine male and female volleyball and basketball players (age: 23.7 ± 4.5 years) performed three single-leg vertical countermovement jumps (SLVCJ) on a contact mat. Vertical jump height and an inter-limb asymmetry index (ASI) were determined. Only 32 (40%) of the subjects had a concordance between the perception of their dominant leg and the limb reaching the highest jump height. Using the DL as the discriminating variable, significant (p<0.05) inter-limb differences were found in the total group of players. When comparing between sexes, significant differences (p<0.05) arose in the female group only. With regard to the WL vs. the SL, significant (p<0.05) differences were noted in the whole group and when stratified into males and females. The mean ASI ranged from 9.31% (males) to 12.84% (females) and from 10.49% (males) to 14.26% (females), when comparing the DL vs. the NDL and the SL vs. the WL, respectively. Subjective expression of leg dominance cannot be used as a predictor of limb jump performance. Vertical jump asymmetry of 10-15% exists and this can be considered as a reference value for male and female basketball and volleyball players. PMID:28149351

  16. Tracking of ball and players in beach volleyball videos.

    PubMed

    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.

  17. 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

  18. Overload and neovascularization of shoulder tendons in volleyball players

    PubMed Central

    2012-01-01

    Background In overhead sports like volleyball, the onset of a rotator cuff tendinopathy due to functional overload is a common observation. An angiofibroblastic etiopathogenesis has been hypothesized, whereby a greater anaerobic metabolism occurs in critical zones of the tendon with a lower degree of vascularization; this would induce collagen and extracellular matrix degradation, that could then trigger a compensatory neovascularization response. We performed a clinical observational study of 80 elite volleyball players, monitoring the perfusion values of the supraspinatus tendons by oximetry. Results No statistically significant differences were found between the oximetry data and age, sex or years of sports activity, nor when comparing the right and left arm or the dominant and non-dominant arm. A statistically significant difference was found for the dominant arm values in relation to the competitive role, higher values being obtained in outside hitters (62.7%) than middle hitters (53.7%) (p = 0.01), opposite hitters (55.5%) (p = 0.02) and libero players (54.4%) (p = 0.008), whereas there were no differences in setters (56.2%) (p > 0.05). Conclusions The different tendon vascularization values found in players with different roles in the team may be attributed to a response to the specific biomechanical demands posed by the different overhead throwing roles. PMID:22853746

  19. Anthropometric and physiological characteristics of junior elite volleyball players

    PubMed Central

    Duncan, M J; Woodfield, L; al‐Nakeeb, Y

    2006-01-01

    Objectives To investigate the anthropometric and physiological characteristics of junior elite volleyball players. Method Twenty five national level volleyball players (mean (SD) age 17.5 (0.5) years) were assessed on a number of physiological and anthropometric variables. Somatotype was assessed using the Heath‐Carter method, body composition (% body fat, % muscle mass) was assessed using surface anthropometry, leg strength was assessed using a leg and back dynamometer, low back and hamstring flexibility was assessed using the sit and reach test, and the vertical jump was used as a measure of lower body power. Maximal oxygen uptake was predicted using the 20 m multistage fitness test. Results Setters were more ectomorphic (p<0.05) and less mesomorphic (p<0.01) than centres. Mean (SD) of somatotype (endomorphy, mesomorphy, ectomorphy) for setters and centres was 2.6 (0.9), 1.9 (1.1), 5.3 (1.2) and 2.2 (0.8), 3.9 (1.1), 3.6 (0.7) respectively. Hitters had significantly greater low back and hamstring flexibility than opposites. Mean (SD) for sit and reach was 19.3 (8.3) cm for opposites and 37 (10.7) cm for hitters. There were no other significant differences in physiological and anthropometric variables across playing positions (all p>0.05). Conclusion Setters tend to be endomorphic ectomorphs, hitters and opposites tend to be balanced ectomorphs, whereas centres tend to be ectomorphic mesomorphs. These results indicate the need for sports scientists and conditioning professionals to take the body type of volleyball players into account when designing individualised position specific training programmes. PMID:16799112

  20. Relations of competitive state anxiety and efficacy of young volleyball players.

    PubMed

    Milavić, Boris; Jurko, Damir; Grgantov, Zoran

    2013-05-01

    With the aim of validating the Competitive State Anxiety Inventory on a population of young Croatian volleyball players, 286 examinees, 106 male and 180 female volleyball players (average age of 16.09+/-1.83), filled out the CSAI-2, constructed by Martens, Vealey, Burton, Bump and Smith (1990)1. Given the fact that all scales of the Competitive State Anxiety Inventory have good homogeneity, reliability and sensitivity, it can be concluded that they represent high-quality measuring instruments for measuring psychological characteristics of young volleyball players. Young male and female volleyball players generally have a moderate level of self-confidence, and their cognitive anxiety is more prominent that somatic anxiety. In order to determine the age and gender differences in somatic and cognitive anxiety and self-confidence, parametric analysis of differences was performed and coefficients of the independent samples t-test were calculated. By analysis of differences according to age, it has been established that female junior players, in relation to female youth players, express a significantly lower level of somatic and cognitive anxiety and a significantly higher level of self-confidence. As opposed to female players, male youth and junior players do not differ in any of the analysed variables. By analysis of differences according to gender, it has been established that male youth players have a significantly higher level of self-confidence in comparison to female youth players. No significant differences were found in the level of competitive anxiety and self-confidence by analysis of variance between different player roles. No significant differences were found by discriminant analysis in somatic and cognitive anxiety, and self-confidence of female volleyball players of different situational efficacy. The group of least efficient male volleyball players is characterized by a very low level of self-confidence, while the most efficient group of volleyball

  1. Risk factors for patellar tendinopathy in basketball and volleyball players: a cross-sectional study.

    PubMed

    van der Worp, H; van Ark, M; Zwerver, J; van den Akker-Scheek, I

    2012-12-01

    Patellar tendinopathy (PT) has a multifactorial etiology, and many possible risk factors have been described in the literature. The findings are conflicting, though, and most research has been conducted on elite athletes. The aim of the current study is to determine the risk factors for PT in a large representative sample of basketball and volleyball players. Separate risk factors for men and women, basketball and volleyball players, and athletes with unilateral and bilateral PT were identified. All basketball and volleyball players between ages 18 and 35 from the Dutch Basketball Association and the Dutch Volleyball Association were invited to complete an online questionnaire on knee complaints and risk factors for PT. The logistic regression analyses included 2224 subjects. The risk factors for PT were age, playing at the national level, being male and playing volleyball (compared with playing basketball). The risk factors for men and women were comparable. Among volleyball players, outside hitters and middle blockers/hitters had an increased risk compared with setters. For basketball players, no risk factors could be identified. No differences in the risk factors were found between athletes with unilateral and bilateral PT. These findings should be taken into account for prevention and rehabilitation purposes.

  2. 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.

  3. Field test for mechanical efficiency evaluation in matching volleyball players.

    PubMed

    Laconi, P; Melis, F; Crisafulli, A; Sollai, R; Lai, C; Concu, A

    1998-01-01

    Field tests were performed in 10 volleyball (VB) players (4 females and 6 males) in order to obtain an index of mechanical work efficiency (mu' = Wmec/Woxy) while athletes played a game. Wmec was the mechanical work output, obtained by means of home made video image analysis software, by summing potential, kinetic translational and kinetic rotational energies of running and jumping athletes. Woxy was the oxidative energy consumption obtained from O2 consumption (VO2) by a telemetry device (Cosmed K2) that also gave values of pulmonary ventilation (VE) and heart rate (HR). VB were studied at rest before a game (R), during attacking phases (A) and during defensive phases (D). At R were found: VE = 11 +/- 1 l x min(-1), HR = 78 +/- 7b x min(-1), VO2 = 3.71 +/- 1.1 ml x kg(-1) x min(-1), Woxy = 75.1 +/- 22.3 J x kg(-1) x min(-1). During A all variables increased: VE = 49 +/- 6l x min(-1), HR = 149 +/- 15 b x min(-1), VO2 = 23.1 +/- 3.3ml x kg(-1) x min(-1), Woxy = 482.8 +/- 69.0 J x kg(-1) x min(-1), and Wmec 275.5 +/- 57.0 J x kg(-1) x min(-1) with mu'=0.57 +/- 0.09. In D HR (-9%), VE, VO2 and Woxy (-18%) were reduced when compared to A, decreasing mu' to 0.21 +/- 0.05. On the other hand mu' was found higher than 0.25 during A indicating an anaerobic contribution to energy expenditure; in D the mu' lower than 0.25 indicated a restoration of anaerobic energy sources. It might be proposed that a greater difference in mu' values between A and D also means a higher anaerobic energy contribution to the volleyball game.

  4. 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.

  5. Self-reported symptoms and risk factors for digital ischaemia among international world-class beach volleyball players.

    PubMed

    Van De Pol, Daan; Alaeikhanehshir, Sena; Maas, Mario; Kuijer, P Paul F M

    2016-01-01

    The prevalence of ischaemia-related symptoms is remarkably high among elite indoor volleyball players. Since the exposure to sport-specific demands may be higher in beach volleyball compared to indoor volleyball, the aim of this study was to assess the prevalence of ischaemia-related symptoms and associated risk factors among world-class beach volleyball players. Therefore, a questionnaire survey was performed among beach volleyball players active during the 2013 Grand Slam Beach Volleyball in the Netherlands. In total, 60 of the 128 beach volleyball players (47%) participated: 26 males and 34 females from 17 countries. The self-reported prevalence of cold or blue or pale digits in the dominant hand during or immediately after practice or competition was 38% (n = 23). Two risk factors were independently associated with symptoms of blue or pale digits: more than 14 years playing volleyball (odds ratio (OR) 4.42, 90% confidence interval (90% CI) 1.30-15.07) and sex (female) (OR 4.62, 90% CI 1.15-18.57). In conclusion, the prevalence of symptoms associated with digital ischaemia is high among international world-class beach volleyball players. Female sex and the length of the volleyball career were independently associated with an increased risk of ischaemia-related symptoms. The high prevalence of these seemingly innocuous symptoms and possible associated risk factors warrant regular monitoring since early detection can potentially prevent thromboembolic complications and irreversible tissue damage.

  6. Does the adolescent patellar tendon respond to 5 days of cumulative load during a volleyball tournament?

    PubMed

    van Ark, M; Docking, S I; van den Akker-Scheek, I; Rudavsky, A; Rio, E; Zwerver, J; Cook, J L

    2016-02-01

    Patellar tendinopathy (jumper's knee) has a high prevalence in jumping athletes. Excessive load on the patellar tendon through high volumes of training and competition is an important risk factor. Structural changes in the tendon are related to a higher risk of developing patellar tendinopathy. The critical tendon load that affects tendon structure is unknown. The aim of this study was to investigate patellar tendon structure on each day of a 5-day volleyball tournament in an adolescent population (16-18 years). The right patellar tendon of 41 players in the Australian Volleyball Schools Cup was scanned with ultrasound tissue characterization (UTC) on every day of the tournament (Monday to Friday). UTC can quantify structure of a tendon into four echo types based on the stability of the echo pattern. Generalized estimating equations (GEE) were used to test for change of echo type I and II over the tournament days. Participants played between eight and nine matches during the tournament. GEE analysis showed no significant change of echo type percentages of echo type I (Wald chi-square = 4.603, d.f. = 4, P = 0.331) and echo type II (Wald chi-square = 6.070, d.f. = 4, P = 0.194) over time. This study shows that patellar tendon structure of 16-18-year-old volleyball players is not affected during 5 days of cumulative loading during a volleyball tournament.

  7. Physiologic performance test differences in female volleyball athletes by competition level and player position.

    PubMed

    Schaal, Monique; Ransdell, Lynda B; Simonson, Shawn R; Gao, Yong

    2013-07-01

    The purpose of this study was to examine physiologic performance test differences by competition level (high school and Division-I collegiate athletes) and player position (hitter, setter, defensive specialist) in 4 volleyball-related tests. A secondary purpose was to establish whether a 150-yd shuttle could be used as a field test to assess anaerobic capacity. Female participants from 4 varsity high school volleyball teams (n = 27) and 2 Division-I collegiate volleyball teams (n = 26) were recruited for the study. Participants completed 4 performance-based field tests (vertical jump, agility T-test, and 150- and 300-yd shuttle runs) after completing a standardized dynamic warm-up. A 2-way multivariate analysis of variance with Bonferroni post hoc adjustments (when appropriate) and effect sizes were used for the analyses. The most important findings of this study were that (a) college volleyball athletes were older, heavier, and taller than high school athletes; (b) high school athletes had performance deficiencies in vertical jump/lower-body power, agility, and anaerobic fitness; (c) lower-body power was the only statistically significant difference in the performance test measures by player position; and (d) the correlation between the 150- and 300-yd shuttle was moderate (r = 0.488). Female high school volleyball players may enhance their ability to play collegiate volleyball by improving their vertical jump, lower-body power, agility, and anaerobic fitness. Furthermore, all player positions should emphasize lower-body power conditioning. These physical test scores provide baseline performance scores that should help strength and conditioning coaches create programs that will address deficits in female volleyball player performance, especially as they transition from high school to college.

  8. Anthropometric, body composition and somatotype characteristics of elite female volleyball players from the highest Spanish league.

    PubMed

    Martín-Matillas, Miguel; Valadés, David; Hernández-Hernández, Elena; Olea-Serrano, Fátima; Sjöström, Michael; Delgado-Fernández, Manuel; Ortega, Francisco B

    2014-01-01

    This study aimed to describe morphological characteristics of elite female volleyball players from the highest Spanish league, with special focus on differences by performance level and playing positions. Nearly all female players playing in the highest Spanish volleyball league during season 2003/2004 participated in this study (N=148 elite players, 92% of the total). Anthropometric, body composition and somatotype parameters according to performance and playing positions were analysed. The players' characteristics were as follows; body mass 72.3 ± 8.4 kg; stature 179.8 ± 7.1 cm; body fat 24.0 ± 3.1% and skeletal muscle mass 27.3 ± 2.9 kg. Mean somatotype was 3.1 ± 0.7; 3.4 ± 0.9; 3.1 ± 0.9 characterised as central with a tendency to balanced mesomorph. Top level players (whose teams were better classified in the team performance ranking) were taller, had higher skeletal muscle mass and ectomorphy, and had a lower level of adiposity markers, compared with lower level players. Players selected for their respective National teams (individual performance) were taller, heavier, had higher muscle mass and lower endomorphy than non-selected players. Differences according to playing positions were found. This study provides a complete set of reference data on anthropometry, body composition and somatotype of elite female volleyball players. Morphological differences have been identified according to performance level and playing position.

  9. Physical fitness qualities of professional volleyball players: determination of positional differences.

    PubMed

    Marques, Mário C; van den Tillaar, Roland; Gabbett, Tim J; Reis, Victor M; González-Badillo, Juan J

    2009-07-01

    The purpose of this study was to investigate the anthropometric and strength characteristics of elite male volleyball athletes and to determine if differences exist in these characteristics according to playing position. A group of 35 professional male team volleyball players (mean +/- SD age: 26.6 +/- 3.1 years) participated in the study. Players were categorized according to playing position and role: middle blockers (n = 9), opposite hitters (n = 6), outside hitters (n = 10), setters (n = 6), and liberos (n = 4). Height, body mass, muscular strength (4 repetition maximum bench press and 4 repetition maximum parallel squat tests), and muscular power (overhead medicine ball throw, countermovement jump) were assessed. Significant differences (p < 0.05) were found among the 5 positional categories. The results indicated that the middle blockers and opposite hitters were the tallest and heaviest players, whereas the libero players were the lightest. Differences were also found in bench press maximal strength, with the middle blockers and opposite players significantly stronger (p < 0.05) than the setters and liberos. The setter positional group had significantly poorer (p < 0.05) parallel squat performances than the outside hitter and opposite hitter groups. No other significant differences (p > 0.05) were found among groups for the strength and power parameters. These results demonstrate that significant anthropometric and strength differences exist among playing positions in elite male volleyball players. In addition, these findings provide normative data for elite male volleyball players competing in specific individual playing positions. From a practical perspective, sport scientists and conditioning professionals should take the strength and anthropometric characteristics of volleyball players into account when designing individualized position-specific training programs.

  10. 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

  11. High Prevalence of Disc Degeneration and Spondylolysis in the Lumbar Spine of Professional Beach Volleyball Players

    PubMed Central

    Külling, Fabrice A.; Florianz, Hannes; Reepschläger, Bastian; Gasser, Johann; Jost, Bernhard; Lajtai, Georg

    2014-01-01

    Background: Beach volleyball is an intensive sport with high impact on the lumbar spine. Low back pain (LBP) is frequent among elite players. Increased prevalence of pathological changes on magnetic resonance imaging (MRI) in the lumbar spine of elite athletes has been reported. Hypothesis: There is an increased prevalence of disc degeneration and spondylolysis in the MRI of the lumbar spine of professional beach volleyball players. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-nine fully competitive professional male volleyball players (mean age, 28 years) completed outcomes questionnaires and underwent a complete clinical examination and an MRI of their lumbar spine. Results: Whereas 86% of players suffered from LBP during their career, the incidence of LBP in the last 4 weeks was 35%. Pain rated using a visual analog scale (VAS) averaged 3 points (range, 0-8). Twenty-three of 29 players (79%) had at least 1 degenerated disc of Pfirrmann grade ≥3. The most affected spinal levels were L4-5 in 14 (48%) and L5-S1 in 15 players (52%); both levels were involved in 5 players (17%). Six of 29 (21%) players showed a spondylolysis grade 4 according to the Hollenburg classification; there was evidence of spondylolisthesis in 2 players. There was no significant correlation between LBP and MRI abnormalities. Conclusion: In the lumbar spine MRI of professional beach volleyball players, the prevalence of disc degeneration is 79%. Spondylolysis (21%) is up to 3 times higher compared with the normal population. Abnormal MRI findings did not correlate with LBP, thus MRIs have to be interpreted with caution. PMID:26535316

  12. Relations of attachment styles and group cohesion in premier league female volleyball players.

    PubMed

    Tiryaki, M Sefik; Cepikkurt, Fatma

    2007-02-01

    The relations of attachment styles with group cohesion were monitored for premier league female volleyball teams. 74 volleyball players from 8 teams responded to the Relationship Scales Questionnaire and Group Environment Questionnaire. Pearson correlations indicated significant association of attachment styles with group cohesion. Specifically, a significant negative correlation was found between female volleyball players' individual attraction to the group-social subscale and fearful attachment style. In addition, there was a significant positive correlation for scores on the group integration-social and secure and preoccupied attachment subscales and a significant negative correlation for scores on the group integration-task subscale and preoccupied attachment style. In conclusion, attachment styles might be considered important in predicting group cohesion

  13. Comparison of Total Antioxidant Capacity Oxidative Stress and Blood Lipoprotein Parameters in Volleyball Players and Sedentary

    ERIC Educational Resources Information Center

    Gokhan, Ismail

    2013-01-01

    This study aims to measure, then compare sedentary blood lipoproteins, oxidant- antioxidant state and oxidative stress index in volleyball players. The experimental group of the research consists of regularly practising 20 boys between the ages of 12 and 17, and the control group comprises 32 children practising no particular sports branch, 12 of…

  14. Role of Uniforms in the Body Image of Female College Volleyball Players

    ERIC Educational Resources Information Center

    Steinfeldt, Jesse A.; Zakrajsek, Rebecca A.; Bodey, Kimberly J.; Middendorf, Katharine G.; Martin, Scott B.

    2013-01-01

    Female student athletes often desire a muscular body to be successful in sport, but this body type does not conform to traditional cultural norms of femininity. In this study, the authors qualitatively examined the experiences of female intercollegiate volleyball players to better understand their beliefs about their bodies--both as athletes and…

  15. Rehabilitation protocol for patellar tendinopathy applied among 16- to 19-year old volleyball players.

    PubMed

    Biernat, Ryszard; Trzaskoma, Zbigniew; Trzaskoma, Lukasz; Czaprowski, Dariusz

    2014-01-01

    The aim of the study was to investigate the efficacy of rehabilitation protocol applied during competitive period for the treatment of patellar tendinopathy. A total of 28 male volleyball players were divided into two groups. Fifteen from experimental group (E) and 13 from control group (C) fulfilled the same tests 3 times: before the training program started (first measurement), after 12 weeks (second measurement) and after 24 weeks (third measurement). The above-mentioned protocol included the following: USG imagining with color Doppler function, clinical testing, pain intensity evaluation with VISA-P questionnaire, leg muscle strength and power and jumping ability measurements. The key element of the rehabilitation program was eccentric squat on decline board with additional unstable surface. The essential factor of the protocol was a set of preventive functional exercises, with focus on eccentric exercises of hamstrings. Patellar tendinopathy was observed in 18% of the tested young volleyball players. Implementation of the presented rehabilitation protocol with eccentric squat on decline board applied during sports season lowered the pain level of the young volleyball players. Presented rehabilitation protocol applied without interrupting the competitive period among young volleyball players together with functional exercises could be an effective method for the treatment of patellar tendinopathy.

  16. [Injured players candidates for professional volleyball team: sign them up or not?].

    PubMed

    Tsur, Atzmon

    2012-02-01

    Competitive volleyball teams master six basic skills: serve, pass, set, attack, block and dig. Each of these skills comprises a number of specific techniques, considered standard practice in high-level volleyball. Five professional volleyball players were candidates to join a first division team in Israel. Their medical dossier presented previous injuries that occurred during their sport's activity. Two of the players had a suprascapular nerve injury, one had a lesion in the hamstrings, another one had an operated ankle sprain and the fifth one had an operated anterior cruciate ligament (ACL) tear in both knees and a mallet fifth finger. The team physician had to make the decision as to whether they are able to continue playing volleyball at a high level, taking into consideration the different skills necessary in this sport. Players having suprascapular nerve injury might have difficulties to hit the serve, to hit and to block the ball. Those with unstable knee or ankle take a risk white landing. Lesions in the hamstrings cause local pain during jumping to attack or to block the ball and a mallet finger will disturb the player when attempting to set the ball, to handle it in attack or to block.

  17. Correspondence between training load executed by volleyball players and the one observed by coaches.

    PubMed

    Rodríguez-Marroyo, Jose A; Medina, Javier; García-López, Juan; García-Tormo, José V; Foster, Carl

    2014-06-01

    The main aim of this study was to compare the training load (TL) executed by volleyball players with that observed by coaches. Second, we analyzed the influence of the coaches' experience in the estimated TL. Twelve female volleyball players and 4 male coaches participated in this study. During a period of 15 weeks, physical (PT) and technical-tactical training sessions and matches were monitored. In each session, the session rating of perceived exertion (sRPE) was recorded to analyze the players' exercise intensity and TL(RP)E. Coaches were present in all sessions and rated their estimate of sRPE at the same time as the players to calculate the coaches' TL(RPE). Both players' and coaches' mean sRPE (4.0 ± 1.1, 3.7 ± 1.1, and 3.8 ± 1.0 in players and expert and beginning coaches, respectively) and TLRPE (380.1 ± 106.8, 358.3 ± 110.5, and 359.7 ± 108.0 in players and expert and beginning coaches, respectively) were similar. However, a higher (p < 0.01) sRPE and TL(RPE) were observed in the players during PT. In general, the weekly TL(RPE) variation over the course of this study was similar in players and coaches. The players' sRPE and TL(RPE) were correlated (p < 0.01) with expert and beginner coaches' RPE (r = 0.70 and 0.72, respectively) and TL(RPE) (r = 0.75 and 0.76, respectively). In conclusion, the present findings show the correspondence between players' and coaches' sRPE and TL(RPE) regardless of their experience. Hence, coaches' TL(RPE) could be a useful and practical method to monitor and control the TL and other derived parameters in an easy way during volleyball.

  18. Enhancing physical performance in male volleyball players with a caffeine-containing energy drink.

    PubMed

    Del Coso, Juan; Pérez-López, Alberto; Abian-Vicen, Javier; Salinero, Juan Jose; Lara, Beatriz; Valadés, David

    2014-11-01

    There are no scientific data about the effects of caffeine intake on volleyball performance. The aim of this study was to investigate the effect of a caffeine-containing energy drink to enhance physical performance in male volleyball players. A double-blind, placebo-controlled, randomized experimental design was used. In 2 different sessions separated by 1 wk, 15 college volleyball players ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed volleyball-specific tests: standing spike test, maximal squat jump (SJ), maximal countermovement jump (CMJ), 15-s rebound jump test (15RJ), and agility T-test. Later, a simulated volleyball match was played and recorded. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased ball velocity in the spike test (73 ± 9 vs 75 ± 10 km/h, P < .05) and the mean jump height in SJ (31.1 ± 4.3 vs 32.7 ± 4.2 cm, P < .05), CMJ (35.9 ± 4.6 vs 37.7 ± 4.4 cm, P < .05), and 15RJ (29.0 ± 4.0 vs 30.5 ± 4.6 cm, P < .05). The time to complete the agility test was significantly reduced with the caffeinated energy drink (10.8 ± 0.7 vs 10.3 ± 0.4 s, P < .05). In addition, players performed successful volleyball actions more frequently (24.6% ± 14.3% vs 34.3% ± 16.5%, P < .05) with the ingestion of the caffeinated energy drink than with the placebo drink during the simulated game. A caffeine-containing energy drink, with a dose equivalent to 3 mg of caffeine per kg body mass, might be an effective ergogenic aid to improve physical performance and accuracy in male volleyball players.

  19. Risk factors associated with self-reported symptoms of digital ischemia in elite male volleyball players in the Netherlands.

    PubMed

    van de Pol, D; Kuijer, P P F M; Langenhorst, T; Maas, M

    2014-08-01

    One in every four elite male volleyball players in the Netherlands reported blue or pale digits in the dominant hand. Little is known about risk factors. To assess whether personal-, sports-, and work-related risk factors are associated with these symptoms in these volleyball players, a survey was performed among elite male volleyball players in the Dutch national top league and in the Dutch beach volleyball team. The questionnaire assessed the presence of symptoms and risk factors. Binary logistic regression was performed to calculate odds ratios (ORs). A total of 99 of the 107 athletes participated - a response rate of 93%. Two sports-related risk factors were associated with symptoms of blue or pale digits: 18-30 years playing volleyball [OR = 6.70; 95% confidence interval (CI) 1.12-29.54] and often/always performing weight training to increase dominant limb strength (OR = 2.70; 95% CI 1.05-6.92). No significant other sports-, personal-, or work-related risk factors were found. Playing volleyball for more than 17 years and often/always performing weight training to increase dominant limb strength were independently associated with an increased risk on ischemia-related complaints of the dominant hand in elite male volleyball players.

  20. Relationships Between Anaerobic Performance, Field Tests and Game Performance of Sitting Volleyball Players.

    PubMed

    Marszalek, Jolanta; Molik, Bartosz; Gomez, Miguel Angel; Skučas, Kęstutis; Lencse-Mucha, Judit; Rekowski, Witold; Pokvytyte, Vaida; Rutkowska, Izabela; Kaźmierska-Kowalewska, Kalina

    2015-11-22

    The aim of this study was to evaluate relationships between anaerobic performance, field tests, game performance and anthropometric variables of sitting volleyball players. Twenty elite Polish sitting volleyball players were tested using the 30 s Wingate Anaerobic Test for arm crank ergometer and participated in six physical field tests. Heights in position to block and to spike, as well as arm reach were measured. Players were observed during the game on the court in terms of effectiveness of the serve, block, attack, receive and defense. Pearson analysis and the Spearman's rank correlation coefficient were used. The strongest correlations were found between the chest pass test and mean power and peak power (r=.846; p=.001 and r=.708; p=.0005, respectively), and also between the T-test and peak power (r= -.718; p=.001). Mean power correlated with the 3 m test (r= -.540; p=.014), the 5 m test (r= -.592; p=.006), and the T-test (r= -.582; p=.007). Peak power correlated with the 3 m test (r= -.632; p=.003), the 5 m test (r= -.613; p=.004), speed & agility (r= -.552; p=.012) and speed & endurance (r=-.546; p=.013). Significant correlations were observed between anthropometric parameters and anaerobic performance variables (p≤.001), and also between anthropometric parameters and field tests (p≤.05). Game performance and physical fitness of sitting volleyball players depended on their anthropometric variables: reach of arms, the position to block and to spike. The chest pass test could be used as a non-laboratory field test of anaerobic performance of sitting volleyball players.

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

    PubMed Central

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

    2016-01-01

    Abstract 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. PMID:28149409

  2. 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.

  3. Vertical jump performance of professional male and female volleyball players: effects of playing position and competition level.

    PubMed

    Sattler, Tine; Hadžić, Vedran; Dervišević, Edvin; Markovic, Goran

    2015-06-01

    Vertical jump (VJ) performance is an important element for successful volleyball practice. The aims of the study were (a) to explore the overall VJ performance of elite volleyball players of both sexes, (b) to explore the differences in VJ performance among different competition levels and different playing positions, and (c) to evaluate the sex-related differences in the role of the arm swing and 3-step approach with arm swing on the jump height. We assessed the VJ capacity in 253 volleyball players (113 males and 140 females) from Slovenian first and second Volleyball Division. The height of squat jump (SJ), countermovement jump, block jump, and attack jump was tested using an Optojump system. We observed significant differences (p ≤ 0.05) in VJ height between different levels of play that were most pronounced in the SJ. Position-related differences in VJ performance were observed in male players between receivers and setters (p ≤ 0.05), whereas in females, VJ performance across different playing positions seems equal. Finally, we found that male players significantly better use the arm swing during VJ than females (p ≤ 0.05), whereas the use of eccentric part of the jump and approach before the spike to improve VJ performance seem to be equally mastered activity in both sexes. These results could assist coaches in the development of jumping performance in volleyball players. Furthermore, presented normative data for jump heights of elite male and female volleyball players could be useful in selection and profiling of young volleyball players.

  4. Anthropometric, Physical, and Age Differences by the Player Position and the Performance Level in Volleyball

    PubMed Central

    Palao, José M.; Manzanares, Policarpo; Valadés, David

    2014-01-01

    The purpose of this paper was to study the ranges in height, weight, age, spike reach, and block reach of volleyball players in relation to the player position and the level of their respective teams in peak performance. The analysed sample included 1454 male and 1452 female players who participated in the volleyball competitions of the Olympic Games and World Championships in the 2000–2012 period. A descriptive, correlational, and longitudinal design was used. The variables studied were: the player position, body height, weight, body mass index, spike reach, block reach, age, and team level. The results show differences between body height, spike and block reaches, and the age of the players by their position. These differences are related to the needs of the different positions with regard to the actions they execute. Middle-blockers, outside-hitters, and opposites have the characteristics that are most suitable for blocking and spiking, and the setters and liberos appear to have characteristics conducive to setting and receiving as well as digging, respectively. The differences found in the studied variables with regard to the playing position are related to players’ needs regarding the actions they perform. Player’s age was a variable that differentiated first teams at this level of competition for males, and physical capacities (body height, weight, spike reach, and block reach) were variables that differentiated first teams at this level of competition for females. PMID:25713683

  5. Data-Based Interval Hitting Program for Female College Volleyball Players

    PubMed Central

    Hurd, Wendy; Hunter-Giordano, Airelle; Axe, Michael; Snyder-Mackler, Lynn

    2009-01-01

    Context: Interval sports programs are a critical rehabilitation element when preparing the injured athlete for a return to preinjury activities. There is currently no published interval hitting program to guide a return to unrestricted play for the volleyball athlete. Therefore, data-based, position-specific overhead hitting programs that control for intensity, time, and number of ball strikes were developed for female college volleyball players. Evidence Acquisition: Records from a single Division I varsity women’s volleyball team were examined for all matches during 7 consecutive years of team play. Data were collected for number of hitting and service attempts per game for each position and the number of games per match. Results: Per game, middle hitters averaged 4.51 attacks and 2.77 service attempts; right-side hitters, 3.58 attacks and 1.26 service attempts; outside hitters, 6.37 attacks and 3.44 service attempts; and setters and defensive specialists, 0.17 attacks and 1.78 service attempts. Conclusion: The interval hitting program can provide rehabilitation specialists with a data-based approach that may facilitate a return to play and minimize the risk of reinjury for volleyball athletes. PMID:23015917

  6. Physical, physiological and performance differences between Canadian national team and universiade volleyball players.

    PubMed

    Smith, D J; Roberts, D; Watson, B

    1992-04-01

    Volleyball has been described as an 'interval' sport with both anaerobic and aerobic components. At the higher skill levels, technical performance may be limited by physical characteristics as well as physical fitness, and performance characteristics such as speed and vertical jump. This investigation compared teams at the two uppermost levels of men's volleyball in Canada for differences in physical, physiological and performance characteristics. The subjects were members of the national (n = 15) and universiade teams (n = 24). The parameters examined included percent body fat, maximal oxygen uptake (VO2 max), anaerobic power, bench press, 20-m sprint time and vertical jumping ability. The only significant difference in physical characteristics between the two teams was in age. Despite similarities in standing and reach height, the national team players had significantly higher block (3.27 vs 3.21 m) and spike (3.43 vs 3.39 m) jumps. An evaluation of anaerobic power measures produced similar power outputs during a modified Wingate test, yet the national team members had higher scores (P less than 0.05) for spike and block jump differences as well as 20-m sprint time. The large aerobic component of elite volleyball play was supported by the high VO2 max value recorded for the national team players (56.7 vs 50.3 ml kg-1 min-1). The results suggest that either years of specific physical conditioning and playing or the selection of individuals for the national team who possess more desirable characteristics as a consequence of genetic endowment, plays a significant role in the preparation of international calibre volleyball players.

  7. Effect of creatine supplementation on jumping performance in elite volleyball players.

    PubMed

    Lamontagne-Lacasse, Martin; Nadon, Raymond; Goulet E, D B

    2011-12-01

    Jump height is a critical aspect of volleyball players' blocking and attacking performance. Although previous studies demonstrated that creatine monohydrate supplementation (CrMS) improves jumping performance, none have yet evaluated its effect among volleyball players with proficient jumping skills. We examined the effect of 4 wk of CrMS on 1 RM spike jump (SJ) and repeated block jump (BJ) performance among 12 elite males of the Sherbrooke University volleyball team. Using a parallel, randomized, double-blind protocol, participants were supplemented with a placebo or creatine solution for 28 d, at a dose of 20 g/d in days 1-4, 10 g/d on days 5-6, and 5 g/d on days 7-28. Pre- and postsupplementation, subjects performed the 1 RM SJ test, followed by the repeated BJ test (10 series of 10 BJs; 3 s interval between jumps; 2 min recovery between series). Due to injuries (N = 2) and outlier data (N = 2), results are reported for eight subjects. Following supplementation, both groups improved SJ and repeated BJ performance. The change in performance during the 1 RM SJ test and over the first two repeated BJ series was unclear between groups. For series 3-6 and 7-10, respectively, CrMS further improved repeated BJ performance by 2.8% (likely beneficial change) and 1.9% (possibly beneficial change), compared with the placebo. Percent repeated BJ decline in performance across the 10 series did not differ between groups pre- and postsupplementation. In conclusion, CrMS likely improved repeated BJ height capability without influencing the magnitude of muscular fatigue in these elite, university-level volleyball players.

  8. Relationships Among Two Repeated Activity Tests and Aerobic Fitness of Volleyball Players.

    PubMed

    Meckel, Yoav; May-Rom, Moran; Ekshtien, Aya; Eisenstein, Tamir; Nemet, Dan; Eliakim, Alon

    2015-08-01

    The purpose of the study was to determine performance indices of a repeated sprint test (RST) and to examine their relationships with performance indices of a repeated jump test (RJT) and with aerobic fitness among trained volleyball players. Sixteen male volleyball players performed RST (6 × 30 m sprints), RJT (6 sets of 6 consecutive jumps), and an aerobic power test (20-m Shuttle Run Test). Performance indices for the RST and the RJT were (a) the ideal 30-m run time (IS), the total run time (TS) of the 6 sprints, and the performance decrement (PD) during the test and (b) the ideal jump height (IJ), the total jump height (TJ) of all the jumps, and the PD during the test, respectively. No significant correlations were found between performance indices of the RST and RJT. Significant correlations were found between PD, IS, and TS in the RST protocol and predicted peak V[Combining Dot Above]O2 (r = -0.60, -0.75, -0.77, respectively). No significant correlations were found between performance indices of the RJT (IJ, TJ, and PD) and peak V[Combining Dot Above]O2. The findings suggest that a selection of repeated activity test protocols should acknowledge the specific technique used in the sport, and that a distinct RJT, rather than the classic RST, is more appropriate for assessing the anaerobic capabilities of volleyball players. The findings also suggest that aerobic fitness plays only a minor role in performance maintenance throughout characteristic repeated jumping activity of a volleyball game.

  9. The effects of 6 weeks of preseason skill-based conditioning on physical performance in male volleyball players.

    PubMed

    Trajković, Nebojša; Milanović, Zoran; Sporis, Goran; Milić, Vladan; Stanković, Ratko

    2012-06-01

    The purpose of this study was to determine the changes in physical performance after a 6-week skill-based conditioning training program in male competitive volleyball players. Sixteen male volleyball players (mean ± SD: age 22.3 ± 3.7 years, body height 190.7 ± 4.2 cm, and body mass 78.4 ± 4.5 kg) participated in this study. The players were tested for sprinting (5- and 10-m sprint), agility, and jumping performance (the vertical-jump test, the spike-jump test, and the standing broad jump [SBJ]). Compared with pretraining, there was a significant improvement in the 5- and 10-m speed. There were no significant differences between pretraining and posttraining for lower-body muscular power (vertical-jump height, spike-jump height, and SBJ) and agility. Based on our results, it could be concluded that a preseason skill-based conditioning program does not offer a sufficient stimulus for volleyball players. Therefore, a general conditioning and hypertrophy training along with specific volleyball conditioning is necessary in the preseason period for the development of the lower-body strength, agility and speed performance in volleyball players.

  10. Effects of sleep deprivation on cardiorespiratory functions of the runners and volleyball players during rest and exercise.

    PubMed

    Azboy, O; Kaygisiz, Z

    2009-03-01

    The effect of sleep deprivation on male runners (age 18.1 +/- 0.35) and volleyball players (age 17.8 +/- 0.36) has not been investigated. Therefore, we studied the possible effect of sleep deprivation in the sportsmen. The athletes performed spirometric tests at rest and then incremental exercise test on ergometer following one night sleep and one night (25-30 h) sleeplessness. Several standard measurements of spirometric function showed no significant change following sleep loss. Sleep loss raised resting oxygen uptake (VO2) in the runners and resting carbon dioxide production (VCO2) in both the runners and the volleyball players (p < 0.05). However, it left heart rate (HR), respiratory quotient (R), minute ventilation (VE) and arterial oxygen saturation (SaO2) unchanged at rest in both groups. Sleep loss decreased time to exhaustion in the volleyball players (p < 0.01). In the runners and the volleyball players, sleep loss did not alter exercise values of HR, VO2, VCO2, R and SaO2, but it reduced exercise VE (p < 0.05). We suggest that one night sleep deprivation may reduce exercise performance by decreasing exercise VE and time to exhaustion. We also indicate that sleep loss may decrease more the performance of volleyball players than that of runners.

  11. A training program to improve neuromuscular indices in female high school volleyball players.

    PubMed

    Noyes, Frank R; Barber-Westin, Sue D; Smith, Stephanie T; Campbell, Thomas

    2011-08-01

    The purpose of this study was to determine if a sports-specific training program could improve neuromuscular indices in female high school volleyball players. We combined components from a previously published knee ligament injury prevention intervention program for jump and strength training with additional exercises and drills to improve speed, agility, overall strength, and aerobic conditioning. We hypothesized that this sports-specific training program would lead to significant improvements in neuromuscular indices in high school female volleyball players. Thirty-four athletes (age 14.5 years ± 1.0) participated in the supervised 6-week program, 3 d·wk(-1) for approximately 90-120 minutes per session. The program was conducted on the school's volleyball court and weight room facilities. The athletes underwent a video drop-jump test, multistage fitness test, vertical jump test, and sit-up test before and after training. A significant increase was found in the mean VO2max score (p < 0.001), where 73% of the athletes improved this score. A significant improvement was found in the sit-up test (p = 0.03) and in the vertical jump test (p = 0.05), where 68% of the athletes increased their scores. In the drop-jump video test, significant increases were found in both the mean absolute knee separation distance (p = 0.002) and in the mean normalized knee separation distance (p = 0.04), indicating improved lower limb alignment on landing. No athlete sustained an injury or developed an overuse syndrome during training. This program significantly improved lower limb alignment on a drop-jump test, abdominal strength, estimated maximal aerobic power, and vertical jump height and may be implemented in high school female volleyball programs.

  12. 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.

  13. Changes in skill and physical fitness following training in talent-identified volleyball players.

    PubMed

    Gabbett, Tim; Georgieff, Boris; Anderson, Steve; Cotton, Brad; Savovic, Darko; Nicholson, Lee

    2006-02-01

    This study investigated the effect of a skill-based training program on measurements of skill and physical fitness in talent-identified volleyball players. Twenty-six talented junior volleyball players (mean +/- SE age, 15.5 +/- 0.2 years) participated in an 8-week skill-based training program that included 3 skill-based court sessions per week. Skills sessions were designed to develop passing, setting, serving, spiking, and blocking technique and accuracy as well as game tactics and positioning skills. Coaches used a combination of technical and instructional coaching, coupled with skill-based games to facilitate learning. Subjects performed measurements of skill (passing, setting, serving, and spiking technique and accuracy), standard anthropometry (height, standing-reach height, body mass, and sum of 7 skinfolds), lower-body muscular power (vertical jump, spike jump), upper-body muscular power (overhead medicine-ball throw), speed (5- and 10-m sprint), agility (T-test), and maximal aerobic power (multistage fitness test) before and after training. Training induced significant (p < 0.05) improvements in spiking, setting, and passing accuracy and spiking and passing technique. Compared with pretraining, there were significant (p < 0.05) improvements in 5- and 10-m speed and agility. There were no significant differences between pretraining and posttraining for body mass, skinfold thickness, lower-body muscular power, upper-body muscular power, and maximal aerobic power. These findings demonstrate that skill-based volleyball training improves spiking, setting, and passing accuracy and spiking and passing technique, but has little effect on the physiological and anthropometric characteristics of players.

  14. Thoracic Outlet Syndrome in a Volleyball Player Due to Nonunion of the First Rib Fracture.

    PubMed

    Puttmann, Kathleen T; Satiani, Bhagwan; Vaccaro, Patrick

    2016-11-01

    Fracture of the first rib with ensuing callus formation is a rare cause of thoracic outlet syndrome. We report a case of a 17-year-old female volleyball player who presented with months of chronic arm pain. Radiographic imaging demonstrated nonunion fracture of the first rib. Physical therapy had been unsuccessful in relieving the pain, and surgical management was performed with resection of the first rib through a transaxillary approach with complete resolution of symptoms. Inflammation surrounding such fractures may destroy tissue planes, making dissection more technically difficult.

  15. Shoulder position sense in volleyball players with infraspinatus atrophy secondary to suprascapular nerve neuropathy.

    PubMed

    Contemori, Samuele; Biscarini, Andrea

    2017-03-29

    Isolated infraspinatus atrophy (IIA) is a common condition among overhead-activity athletes, which affects the hitting shoulder and is caused by suprascapular nerve injury. Since the suprascapular nerve is a mixed nerve, such damage could lead to reduced afferent proprioceptive information and impaired shoulder sensorimotor control. This study aims to evaluate the proprioception of the shoulder with IIA, through the assessment of shoulder position sense. The shoulder position sense was assessed in 24 professional volleyball players (12 players with IIA, and 12 healthy players) with a blind dynamic shoulder repositioning test (all participants were blindfolded during the test). Three functional glenohumeral movements were tested: abduction, forward flexion, and a combination of abduction and external rotation. In all three tested movements, the affected shoulder of players with isolated infraspinatus atrophy showed significantly higher hand position error than the healthy contralateral (P<10(-3) , for all movements) and the healthy control group hitting shoulder (P<10(-3) , for abduction and flexion; P=0.02, for combined movement of abduction and external rotation). The study highlights a reduced sense of position of the hitting shoulder in professional volleyball players with IIA secondary to suprascapular nerve palsy. The higher hand position error of the pathologic shoulder suggests an impairment of the shoulder sensorimotor control system, which likely results from reduced afferent proprioceptive information. Deficient afferent proprioceptive information may result in poor accuracy in descending motor commands and impairment of the shoulder neuromuscular function, leading to reduced shoulder functional stability and increased risk of injury. This article is protected by copyright. All rights reserved.

  16. Analysis of the relationship between the amount of training and cognitive expertise. A study of young volleyball players.

    PubMed

    Gil, Alexander; Moreno, M Perla; Moreno, Alberto; García-González, Luís; Claver, Fernando; Del Villar, Fernando

    2013-03-01

    The main goal of this research was to analyze the relationship between the amount of practice accumulated in training and the level of cognitive expertise achieved by volleyball players who are still in training. Another goal was to determine the number of training hours per week needed to improve knowledge significantly. The study's sample was composed of 520 volleyball players between the ages of 12 and 16 years. The independent variable was the amount of training, defined as the number of weekly hours that the volleyball player devoted to training. The dependent variable was cognitive expertise, measured by declarative knowledge and procedural knowledge. A univariate analysis of variance was done to examine the relationship between the number of weekly hours and the declarative and procedural knowledge reached by volleyball players in the athletic formation training stages. Statistical significance was set at p < 0.05. There were significant differences in knowledge according to the number of weekly training hours (p < 0.001). These results confirm that there is a relationship between the quantity of practice and the development of cognitive expertise. It is recommended that young players dedicate at least 4 hours weekly to training to achieve a significant improvement in cognitive expertise.

  17. A descriptive epidemiological study of shoulder injury in top level English male volleyball players.

    PubMed

    Wang, H K; Cochrane, T

    2001-02-01

    The aims of this study were to estimate the prevalence and incidence of shoulder sports injuries, to discover the main shoulder injury, and to survey outcome of treatment or injuries in top level male volleyball athletes. Furthermore, the actions which most commonly cause injuries and the differences of physical characteristics between injured and healthy players were also investigated. Fifty-nine English Volleyball Federation division one athletes were recruited in the 1997/98 and 1998/99 seasons. All subjects completed two different questionnaires; a First recruitment and monthly Follow-up questionnaire throughout the period in question. Twenty-seven of the fifty-nine athletes had a history of shoulder sports injury, with a total of 29 injuries reported. The results of the First recruitment showed that overuse type injuries (19/29) were the main shoulder injuries. Cuff muscle tendinitis was predominant in these injuries (14/29). Furthermore, spiking was the major action during which a shoulder injury (23/29) first occurred. In the follow-up phase the incidences of shoulder chronic injury (or pain), re-injury, and new injury in these twenty-seven players were 3.0, 9.3 and 1.0 injuries/1,000 hours of exposure respectively. The mean duration of chronic injury or pain was 2.3 +/- 1.3 (+/- SD) months. The distribution of history of regular training, between injured and healthy subject groups, was significantly different (p = 0.008). This study has identified rotator cuff muscle/tendon injuries or involved lesions as the main shoulder injuries in top level English male volleyball athletes. These injuries result in prolonged shoulder pain symptoms.

  18. Analysis of Setting Efficacy in Young Male and Female Volleyball Players

    PubMed Central

    Domínguez, Alberto Moreno; Fernández-Echeverría, Carmen; Rabaz, Fernando Claver; Arroyo, M. Perla Moreno

    2016-01-01

    Abstract The main objective of this study was to analyse the variables that predicted setting efficacy in complex I (KI) in volleyball, in formative categories and depending on gender. The study sample was comprised of 5842 game actions carried out by the 16 male category and the 18 female category teams that participated in the Under-16 Spanish Championship. The dependent variable was setting efficacy. The independent variables were grouped into: serve variables (a serve zone, the type of serve, striking technique, an in-game role of the server and serve direction), reception variables (a reception zone, a receiver player and reception efficacy) and setting variables (a setter‘s position, a setting zone, the type of a set, setting technique, a set’s area and tempo of a set). Multinomial logistic regression showed that the best predictive variables of setting efficacy, both in female and male categories, were reception efficacy, setting technique and tempo of a set. In the male category, the jump serve was the greatest predictor of setting efficacy, while in the female category, it was the set’s area. Therefore, in the male category, it was not only the preceding action that affected setting efficacy, but also the serve. On the contrary, in the female category, only variables of the action itself and of the previous action, reception, affected setting efficacy. The results obtained in the present study should be taken into account in the training process of both male and female volleyball players in formative stages. PMID:28149423

  19. A Psychometric Evaluation of the Group Environment Questionnaire in a Sample of Elite and Regional Level Greek Volleyball Players

    ERIC Educational Resources Information Center

    Ntoumanis, Nikos; Aggelonidis, Yannis

    2004-01-01

    The purpose of this study was to examine the psychometric properties of the Group Environment Questionnaire (GEQ) adapted to the Greek language. The sample consisted of 586 male and female volleyball players of elite and regional level status. Data were analysed from three time points of a competitive season. For each time point, seven competing…

  20. High-Intensity Training Improves Exercise Performance in Elite Women Volleyball Players During a Competitive Season.

    PubMed

    Purkhús, Elisabeth; Krustrup, Peter; Mohr, Magni

    2016-11-01

    Purkhús, E, Krustrup, P, and Mohr, M. High-intensity training improves exercise performance in elite women volleyball players during a competitive season. J Strength Cond Res 30(11): 3066-3072, 2016-Elite women volleyball players (n = 25; mean ± SD: age, 19 ± 5 years; height, 171 ± 7 cm; weight, 63 ± 10 kg) volunteered to participate in the study. They were randomized into a high-intensity training (HIT; n = 13) group and a control (CON; n = 12) group. In addition to the normal team training and games, HIT performed 6-10 × 30-seconds all-out running intervals separated by 3-minute recovery periods 3 times per week during a 4-week in-season period whereas CON only completed the team training sessions and games. Preintervention and postintervention, all players completed the arrowhead agility test (AAT), a repeated sprint test (RST; 5 × 30 meters separated by 25 seconds of recovery), and the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) followed by a-10 minute rest period and the Yo-Yo IR1 test. Mean running distance during HIT in week 1 was 152 ± 4 m and increased (p ≤ 0.05) by 4.6% (159 ± 3 m) in week 4. The AAT performance improved (p ≤ 0.05) by 2.3% (18.87 ± 0.97-18.44 ± 1.06 seconds) and RST by 4.3% postintervention in the HIT group only. Baseline RST fatigue index was 7.0 ± 2.9 and 6.2 ± 5.0% in HIT and CON, respectively, but was lowered (p ≤ 0.05) to 2.7 ± 3.0% posttraining in HIT and remained unaltered in CON (5.5 ± 5.0%). In HIT, Yo-Yo IR2 and Yo-Yo IR1 performance improved by 12.6 and 18.3% postintervention, respectively, with greater (p ≤ 0.05) Yo-yo IR1 change scores than in CON. In conclusion, additional high-intensity in-season training performed as interval running improved agility, repeated sprint ability, and high-intensity intermittent exercise performance in elite women volleyball players.

  1. ACTN3 R577X polymorphism does not influence explosive leg muscle power in elite volleyball players.

    PubMed

    Ruiz, J R; Fernández del Valle, M; Verde, Z; Díez-Vega, I; Santiago, C; Yvert, T; Rodríguez-Romo, G; Gómez-Gallego, F; Molina, J J; Lucia, A

    2011-12-01

    We examined the association of R577X polymorphism (rs1815739) in the α-actinin-3 (ACTN3) gene with "explosive" leg muscle power performance in a group of male and female elite volleyball players (n=66, 31 men, 35 women) and in a group of non-athletic male and female young adults (n=334, 243 men, 91 women). We assessed power performance by means of the vertical squat and counter-movement jump tests. We also determined whether the genotypic frequencies of the ACTN3 R577X genotypes differed between groups. We did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in both groups, regardless of gender (all P>0.05). Genotype frequencies were similar between volleyball and control groups (P=0.095). Moreover, we did not find an association between the ACTN3 R577X polymorphism and the likelihood of being an elite volleyball player using the dominant (RR vs RX+XX) and the recessive model (RR+RX vs XX). In summary, these findings suggest that the ACTN3 R577X polymorphism does not influence explosive leg muscle power in elite volleyball players.

  2. Response time, visual search strategy, and anticipatory skills in volleyball players.

    PubMed

    Piras, Alessandro; Lobietti, Roberto; Squatrito, Salvatore

    2014-01-01

    This paper aimed at comparing expert and novice volleyball players in a visuomotor task using realistic stimuli. Videos of a volleyball setter performing offensive action were presented to participants, while their eye movements were recorded by a head-mounted video based eye tracker. Participants were asked to foresee the direction (forward or backward) of the setter's toss by pressing one of two keys. Key-press response time, response accuracy, and gaze behaviour were measured from the first frame showing the setter's hand-ball contact to the button pressed by the participants. Experts were faster and more accurate in predicting the direction of the setting than novices, showing accurate predictions when they used a search strategy involving fewer fixations of longer duration, as well as spending less time in fixating all display areas from which they extract critical information for the judgment. These results are consistent with the view that superior performance in experts is due to their ability to efficiently encode domain-specific information that is relevant to the task.

  3. Response Time, Visual Search Strategy, and Anticipatory Skills in Volleyball Players

    PubMed Central

    Lobietti, Roberto

    2014-01-01

    This paper aimed at comparing expert and novice volleyball players in a visuomotor task using realistic stimuli. Videos of a volleyball setter performing offensive action were presented to participants, while their eye movements were recorded by a head-mounted video based eye tracker. Participants were asked to foresee the direction (forward or backward) of the setter's toss by pressing one of two keys. Key-press response time, response accuracy, and gaze behaviour were measured from the first frame showing the setter's hand-ball contact to the button pressed by the participants. Experts were faster and more accurate in predicting the direction of the setting than novices, showing accurate predictions when they used a search strategy involving fewer fixations of longer duration, as well as spending less time in fixating all display areas from which they extract critical information for the judgment. These results are consistent with the view that superior performance in experts is due to their ability to efficiently encode domain-specific information that is relevant to the task. PMID:24876946

  4. Reliability and Validity of EN-TreeM Dynamometer for Measurement of Shoulder Rotator Strength in Volleyball Players

    PubMed Central

    Kaleem; Moiz, Jamal Ali; Iqbal, Mohd; Verma, Shalini

    2016-01-01

    Introduction Volleyball involves repeated forceful arm actions that produce a high incidence of shoulder injury. Shoulder rotator strength ratio is an important predictor of the likelihood of shoulder injury, especially, secondary shoulder impingement and instability. Therefore, assessment of muscle strength of external and internal rotators of shoulder is imperative to establish the profiles of shoulder rotator performance, strength ratios, and shoulder mobility of volleyball players. Aim To establish reliability and validity of EN-TreeM dynamometer for the measurement of shoulder rotators strength in volleyball players. Materials and Methods Thirty male volleyball players aged 18-24 years, mean height 1.7m, weight 69.8 Kg and BMI 23.1 participated in the study. They performed 1RM (one repetition maximum) estimation protocols using EN-TreeM dynamometer and free weights for shoulder rotators, to investigate its concurrent validity. A retest using the same protocol was performed 48 hours later to assess test-retest reliability of the EN-TreeM dynamometer. Results The results yielded excellent test-retest reliability (ICC0.96) and internal consistency (Cronbach’s alpha0.98) for both internal and external rotators. The concurrent validity was established using Pearson correlation coefficient (internal rotator r=0.45, p=0.01;External rotator r=0.38, p=0.03). Conclusion The findings establish the reliability and concurrent validity of EN-TreeM dynamometer for the quantification of shoulder rotators strength. Based on these findings in volleyball players, EN-TreeM dynamometer can be used with confidence as an instrument for assessing muscle performance (strength). Additionally, it may also be used for monitoring changes due to rehabilitation interventions in shoulder injuries. PMID:27134986

  5. Passion and coping: relationships with changes in burnout and goal attainment in collegiate volleyball players.

    PubMed

    Schellenberg, Benjamin J I; Gaudreau, Patrick; Crocker, Peter R E

    2013-06-01

    This study examined the relationship between harmonious and obsessive passion and coping, and assessed whether coping mediated the relationship between passion types and changes in burnout and goal attainment. College- and university-level volleyball players (N = 421) completed measures of passion, coping, burnout, and goal attainment at the start and end of a season. Results of structural equation modeling, using a true latent change approach, supported a model whereby types of passion were indirectly related to changes in burnout and goal attainment via coping. Harmonious passion was positively related to task-oriented coping which, in turn, was positively associated with change in goal attainment. Obsessive passion was positively associated with disengagement-oriented coping which, in turn, was positively and negatively associated with changes in burnout and goal attainment, respectively. This study identifies coping as a reason why passionate athletes may experience changes in burnout and goal attainment over the course of a season.

  6. Physical and temporal characteristics of under 19, under 21 and senior male beach volleyball players.

    PubMed

    Medeiros, Alexandre; Marcelino, Rui; Mesquita, Isabel; Palao, José Manuel

    2014-09-01

    This study aimed to assess the effects of age groups and players' role (blocker vs. defender specialist) in beach volleyball in relation to physical and temporal variables, considering quality of opposition. 1101 rallies from Under 19 (U19), 933 rallies from Under 21 (U21), and 1480 rallies from senior (senior) (Men's Swatch World Championships, 2010-2011) were observed using video match analysis. Cluster analysis was used to set teams' competitive levels and establish quality of opposition as "balanced", "moderate balanced" and "unbalanced" games. The analyzed variables were: temporal (duration of set, total rest time, total work time, duration of rallies, rest time between rallies) and physical (number of jumps and number of hits done by defenders and blockers) characteristics. A one-way ANOVA, independent samples t-test and multinomial logistic regression were performed to analyze the variables studied. The analysis of temporal and physical characteristics showed differences considering age group, player's role and quality of opposition. The duration of set, total rest time, and number of jumps done by defenders significantly increased from the U19 to senior category. Multinomial logistic regression showed that in: a) balanced games, rest time between rallies was higher in seniors than in U19 or U21; number of jumps done by defenders was higher in seniors than in U19) and U21; b) moderate balanced games, number of jumps done by defenders was higher in seniors than in U21 and number of jumps done by blockers was smaller in U19 than U21 or seniors; c) unbalanced games, no significant findings were shown. This study suggests differences in players' performances according to age group and players' role in different qualities of opposition. The article provides reference values that can be useful to guide training and create scenarios that resemble a competition, taking into account physical and temporal characteristics. Key PointsPlayer roles, quality of opposition

  7. The effect of assisted jumping on vertical jump height in high-performance volleyball players.

    PubMed

    Sheppard, Jeremy M; Dingley, Andrew A; Janssen, Ina; Spratford, Wayne; Chapman, Dale W; Newton, Robert U

    2011-01-01

    Assisted jumping may be useful in training higher concentric movement speed in jumping, thereby potentially increasing the jumping abilities of athletes. The purpose of this study was to evaluate the effects of assisted jump training on counter-movement vertical jump (CMVJ) and spike jump (SPJ) ability in a group of elite male volleyball players. Seven junior national team volleyball players (18.0±1.0 yrs, 200.4±6.7 cm, and 84.0±7.2 kg) participated in this within-subjects cross-over counter-balanced training study. Assisted training involved 3 sessions per week of CMVJ training with 10 kg of assistance, applied through use of a bungee system, whilst normal jump training involved equated volume of unassisted counter-movement vertical jumps. Training periods were 5 weeks duration, with a 3-week wash-out separating them. Prior to and at the conclusion of each training period jump testing for CMVJ and SPJ height was conducted. Assisted jump training resulted in gains of 2.7±0.7 cm (p<0.01, ES=0.21) and 4.6±2.6 cm (p<0.01, ES=0.32) for the CMVJ and SPJ respectively, whilst normal jump training did not result in significant gains for either CMVJ or SPJ (p=0.09 and p=0.51 respectively). The changes associated with normal jump training and assisted jump training revealed significant differences in both CMVJ and SPJ (p=<0.03) in favour of the assisted jump condition, with large effect (CMVJ, ES=1.22; SPJ, ES=1.31). Assisted jumping may promote the leg extensor musculature to undergo a more rapid rate of shortening, and chronic exposure appears to improve jumping ability.

  8. Generalized Joint Laxity and Ligament Injuries in High School–Aged Female Volleyball Players in Japan

    PubMed Central

    Sueyoshi, Ted; Emoto, Gen; Yuasa, Tomoki

    2016-01-01

    Background: Generalized joint laxity has been linked to ligamentous injuries such as anterior cruciate ligament tear and ankle sprain. Purpose/Hypothesis: The purpose of this study was to investigate generalized joint laxity and incidence of ligament injuries in high school–aged female volleyball players. It was hypothesized that volleyball players with a past history of sprains would have increased generalized joint laxity compared with those without any history and that athletes with multiple sprains would demonstrate with a higher generalized joint laxity score than those who had only 1 sprain. Study Design: Case-control study; Level of evidence, 3. Methods: Forty-seven subjects were tested for generalized joint laxity using the Beighton and Horan Joint Mobility Index (BHJMI). They were categorized into 2 groups based on the presence of past ligament injury: injury group (IG) and noninjury group (NG). The IG group was further divided into 2 groups based on whether they had a single ligamentous injury (IGS) or multiple injuries (IGM) in the past to study whether there was any difference in scores between the subgroups. The collected data were analyzed statistically with 1-way analysis of variance. Results: Subjects in the IG group scored significantly higher on the BHJMI than those in the NG group. The mean score for the IG group was 2.40 ± 1.42, as opposed to 1.24 ± 1.09 for the NG group (P = .006). Eleven subjects in the IG group had suffered multiple injuries or recurrent injuries (IGM) and scored significantly higher than the remaining 19 individuals in the IG group, who had only sustained a single injury (IGS). The mean BHJMI scores were 3.18 ± 1.47 and 1.95 ± 1.22 for IGM and IGS, respectively (P = .02). Conclusion: Female athletes with a high generalized joint laxity score may be more prone to ligament injury and potentially to recurrent ligament injuries. PMID:27761474

  9. Acute Consumption of an Energy Drink Does Not Improve Physical Performance of Female Volleyball Players.

    PubMed

    Fernández-Campos, Catalina; Dengo, Ana L; Moncada-Jiménez, José

    2015-06-01

    To determine the acute effect of an energy drink (ED) on physical performance of professional female volleyball players. 19 females (age= 22.3 ± 4.9 yr.; height= 171.8 ± 9.4 cm; weight= 65.2 ± 10.1 kg) participated in a randomized, crossover, double-blind study to measure grip strength, vertical jump and anaerobic power in 3 different sessions (ED, placebo [PL] or no beverage [CTL]). For each session, participants arrived in a fasted state, consumed a standardized breakfast meal, and 1 hr later completed the 3 baseline performance tests without having ingested the beverage. After completing the premeasurements, the athletes drank 6 ml/kg of body weight of the ED or PL and in the CTL condition no beverage was consumed. Posttest measurements were taken 30 min after the ingestion of liquids. A 3 × 2 repeated-measures ANOVA revealed no significant within-session and measurement time interactions for each performance test. Regardless of the measurement time, right hand grip strength was significantly higher in the ED condition (34.6 ± 0.9 kg) compared with PL (33.4 ± 1.1 kg) and CTL (33.6 ± 1.0 kg) (p < 0.05). Regardless of the beverage ingested, averaged right hand grip strength, taking into account all 3 testing conditions, increased from pre to posttesting (Pre = 33.8 ± 0.9 kg vs. Post = 33.9 ± 1.0 kg; p = 0.029), as did the averaged fatigue index, obtained from the anaerobic power test (Pre = 65.9± 2.2% vs. Post = 68.7± 2.0%; p= 0.049). The acute ingestion of an ED did not improve physical performance of professional Costa Rican female volleyball players.

  10. Anatomical glenohumeral internal rotation deficit and symmetric rotational strength in male and female young beach volleyball players.

    PubMed

    Saccol, Michele Forgiarini; Almeida, Gabriel Peixoto Leão; de Souza, Vivian Lima

    2016-08-01

    Beach volleyball is a sport with a high demand of shoulder structures that may lead to adaptations in range of motion (ROM) and strength like in other overhead sports. Despite of these possible alterations, no study evaluated the shoulder adaptations in young beach volleyball athletes. The aim of this study was to compare the bilateral ROM and rotation strength in the shoulders of young beach volleyball players. Goniometric passive shoulder ROM of motion and isometric rotational strength were evaluated in 19 male and 14 female asymptomatic athletes. External and internal ROM, total rotation motion, glenohumeral internal rotation deficit (GIRD), external rotation and internal rotation strength, bilateral deficits and external rotation to internal rotation ratio were measured. The statistical analysis included paired Student's t-test and analysis of variance with repeated measures. Significantly lower dominant GIRD was found in both groups (p<0.05), but only 6 athletes presented pathological GIRD. For strength variables, no significant differences for external or internal rotation were evident. Young beach volleyball athletes present symmetric rotational strength and shoulder ROM rotational adaptations that can be considered as anatomical. These results indicate that young practitioners of beach volleyball are subject to moderate adaptations compared to those reported for other overhead sports.

  11. Injury risk is low among world-class volleyball players: 4-year data from the FIVB Injury Surveillance System

    PubMed Central

    Bere, Tone; Kruczynski, Jacek; Veintimilla, Nadège; Hamu, Yuichiro; Bahr, Roald

    2015-01-01

    Background Little is known about the rate and pattern of injuries in international volleyball competition. Objective To describe the risk and pattern of injuries among world-class players based on data from the The International Volleyball Federation (FIVB) Injury Surveillance System (ISS) (junior and senior, male and female). Methods The FIVB ISS is based on prospective registration of injuries by team medical staff during all major FIVB tournaments (World Championships, World Cup, World Grand Prix, World League, Olympic Games). This paper is based on 4-year data (September 2010 to November 2014) obtained through the FIVB ISS during 32 major FIVB events (23 senior and 9 junior). Results The incidence of time-loss injuries during match play was 3.8/1000 player hours (95% CI 3.0 to 4.5); this was greater for senior players than for junior players (relative risk: 2.04, 1.29 to 3.21), while there was no difference between males and females (1.04, 0.70 to 1.55). Across all age and sex groups, the ankle was the most commonly injured body part (25.9%), followed by the knee (15.2%), fingers/thumb (10.7%) and lower back (8.9%). Injury incidence was greater for centre players and lower for liberos than for other player functions; injury patterns also differed between player functions. Conclusions Volleyball is a very safe sport, even at the highest levels of play. Preventive measures should focus on acute ankle and finger sprains, and overuse injuries in the knee, lower back and shoulder. PMID:26194501

  12. Examining correlates of game-to-game variation in volleyball players' achievement goal pursuit and underlying autonomous and controlling reasons.

    PubMed

    Vansteenkiste, Maarten; Mouratidis, Athanasios; Van Riet, Thomas; Lens, Willy

    2014-04-01

    In the current study we aimed to examine the antecedents and outcomes associated with the variability in competitive volleyball players' (N = 67; Mage = 19.45; SD = 5.13) situational achievement goal pursuit and its underlying autonomous and controlling reasons. Players were followed during six consecutive games and data were analyzed through multilevel modeling. Players' dominant contextual goal pursuit reported at the onset of the study related to their situational (i.e., game-specific) goal pursuit. Further, variation in game-to-game mastery-approach goal pursuit, as compared with the pursuit of other achievement goals, related to variation in prosocial behavior. Finally, autonomous reasons underlying situational mastery-approach goal pursuit related positively to games-specific prosocial behavior, enjoyment, and performance satisfaction. The discussion emphasizes the necessity to study players' game-to-game motivational dynamics and the reasons underlying players' achievement goal pursuit.

  13. Reactive Strength Index Modified Is a Valid Measure of Explosiveness in Collegiate Female Volleyball Players.

    PubMed

    Kipp, Kristof; Kiely, Michael T; Geiser, Christopher F

    2016-05-01

    The purpose of this study was to investigate the validity of the reactive strength index modified (RSImod) as a measure of lower body explosiveness. Fifteen female, National Collegiate Athletic Association Division I volleyball players performed vertical countermovement jumps (CMJs) while standing on a force plate. Each player performed 3 CMJs. The vertical ground reaction forces collected during each jump were used to calculate jump height, time to take-off, time to peak force, peak force, peak rate of force development, and peak power; the latter 3 variables were all normalized to body mass. Reactive strength index modified was calculated as the ratio between jump height and time to take-off. All variables, except for jump height, were then entered a factor analysis, which reduced the input data into 2 factors: a force factor and a speed factor. Although RSImod loaded more strongly onto the force factor, further analysis showed that RSImod loaded positively onto both force and speed factors. Visual analysis of the Cartesian coordinates also showed that RSImod loaded into the quadrant of greater force and speed abilities. These results indicate that the construct of RSImod, as derived from CMJ force-time data, captures a combination of speed-force factors that can be interpreted as lower body explosiveness during the CMJ. Reactive strength index modified therefore seems to be a valid measure to study lower body explosiveness.

  14. Influence of dorsiflexion shoes on neuromuscular fatigue of the plantar flexors after combined tapping-jumping exercises in volleyball players.

    PubMed

    Lapole, Thomas; Ahmaidi, Said; Gaillien, Benjamin; Leprêtre, Pierre-Marie

    2013-07-01

    Dorsiflexion shoes could be useful to increase jumping performance. The aim of the present study was to investigate the impact of wearing shoes inducing moderate dorsiflexion (2°) on neuromuscular fatigue induced by volleyball exercises involving multiple stretch-shortening cycles. Squat jump (SJ) and countermovement jump (CMJ) performance, and plantar flexors isometric voluntary and evoked contractile properties were assessed in 10 unfamiliarized trained volleyball players before and after a 10-minute intensive combined tapping-jumping volleyball exercise performed, in blinded randomized conditions, with neutral (0°) or moderate dorsiflexion (2°). No significant difference was observed on SJ performance in neutral and moderate dorsiflexion conditions. However, CMJ height was initially lower with 2° dorsiflexion compared with 0° (p < 0.05). Height in CMJ was increased after exercise with 2° dorsiflexion shoes and remained unchanged in neutral 0° condition. Combined tapping-jumping volleyball exercise also induced a significant decrease in maximal voluntary contraction (p < 0.001), peak-twitch torque (p = 0.009), contraction time (p < 0.001) and twitch relaxation rate (p = 0.001) values without any significant difference between neutral and dorsiflexion conditions. Voluntary activation level (p = 0.014) and rate of force development (p = 0.05) were also decreased in both conditions. In conclusion, acute moderate dorsiflexion had no effect on jumping performance and neuromuscular fatigue in unfamiliarized trained subjects and altered the elastic energy store in plyometric condition (CMJ). Future studies are necessary to investigate the chronic effect of moderate dorsiflexion on jumping performance and neuromuscular fatigue in trained volleyball players.

  15. Physical and Temporal Characteristics of Under 19, Under 21 and Senior Male Beach Volleyball Players

    PubMed Central

    Medeiros, Alexandre; Marcelino, Rui; Mesquita, Isabel; Palao, José Manuel

    2014-01-01

    This study aimed to assess the effects of age groups and players’ role (blocker vs. defender specialist) in beach volleyball in relation to physical and temporal variables, considering quality of opposition. 1101 rallies from Under 19 (U19), 933 rallies from Under 21 (U21), and 1480 rallies from senior (senior) (Men’s Swatch World Championships, 2010-2011) were observed using video match analysis. Cluster analysis was used to set teams’ competitive levels and establish quality of opposition as “balanced”, “moderate balanced” and “unbalanced” games. The analyzed variables were: temporal (duration of set, total rest time, total work time, duration of rallies, rest time between rallies) and physical (number of jumps and number of hits done by defenders and blockers) characteristics. A one-way ANOVA, independent samples t-test and multinomial logistic regression were performed to analyze the variables studied. The analysis of temporal and physical characteristics showed differences considering age group, player’s role and quality of opposition. The duration of set, total rest time, and number of jumps done by defenders significantly increased from the U19 to senior category. Multinomial logistic regression showed that in: a) balanced games, rest time between rallies was higher in seniors than in U19 or U21; number of jumps done by defenders was higher in seniors than in U19) and U21; b) moderate balanced games, number of jumps done by defenders was higher in seniors than in U21 and number of jumps done by blockers was smaller in U19 than U21 or seniors; c) unbalanced games, no significant findings were shown. This study suggests differences in players’ performances according to age group and players’ role in different qualities of opposition. The article provides reference values that can be useful to guide training and create scenarios that resemble a competition, taking into account physical and temporal characteristics. Key Points Player

  16. Using a practical approach for determining the most effective stretching strategy in female college division I volleyball players.

    PubMed

    Kruse, Nicholas T; Barr, Marcus W; Gilders, Roger M; Kushnick, Michael R; Rana, Sharon R

    2013-11-01

    The purpose of this investigation was to quantify the effects that a practical bout of static stretching (SS) and dynamic stretching (DS) has on maximal countermovement jump (CMJ) height across a time spectrum of 25 minutes in National Collegiate Athletic Association Division I varsity volleyball players. Eleven female varsity volleyball players (mean ± SD; age 20.00 ± 1.55 years; height 1.78 ± 0.08 m; mass 74.55 ± 12.18 kg) volunteered for this investigation. Three days of randomized experimental testing (SS, DS, control) were completed. The SS protocol consisted of stretching 7 muscle groups. The DS protocol consisted of the volleyball team's actual DS routine of equal duration (30 seconds) to SS. Poststretch performance measures of CMJ were determined at 1, 5, 15, and 25 minutes poststretch. Countermovement jump had an acute significant trial-by-time interaction, indicating that DS was found to produce significantly higher scores than the SS and control session at 1 and 5 minutes poststretch, but not at 15 and 25 minutes poststretch. Additionally, there was a timing interaction within trials where SS scores were significantly lower at 1 minute poststretch compared with 5 and 25 minutes poststretch, and DS scores were significantly higher at 1 and 5 minutes poststretch compared with 15 and 25 minutes poststretch. Athletes engaging in competitive power sports should continue to utilize their DS routine but may need to do so within 5 minutes before activity.

  17. Perceived verbal aggressiveness of coaches in volleyball and basketball: a preliminary study.

    PubMed

    Bekiari, Alexandra; Digelidis, Nikolaos; Sakelariou, Kimon

    2006-10-01

    This study examined verbal aggressiveness of coaches as perceived by their athletes, 108 senior athletes (57 boys and 51 girls) ages 15-19 years. Participants were basketball players (56 athletes) and volleyball players (52 athletes) who completed questionnaires. The scale of verbal aggressiveness showed high internal consistency. A two-way analysis of variance, conducted using sex and sport as independent variables to examine interactions, yielded significant differences between adolescent volleyball and basketball athletes. Volleyball athletes had lower scores on the Verbal Aggressiveness Scale than basketball players. Research with larger samples and other sports is recommended.

  18. Utility of Genetic Testing in Elite Volleyball Players with Aortic Root Dilation.

    PubMed

    Herrick, Nicole; Davis, Christopher; Vargas, Lisa; Dietz, Hal; Grossfeld, Paul

    2017-02-25

    Basketball and volleyball attract individuals with a characteristic biophysical profile, mimicking features of Marfan Syndrome (MFS). Consequently, identification of these abnormalities can be lifesaving.

  19. Analysis of the Response Speed of Musculature of the Knee in Professional Male and Female Volleyball Players

    PubMed Central

    Rodríguez-Ruiz, D.; Diez-Vega, I.; Rodríguez-Matoso, D.; Fernandez-del-Valle, M.; Sagastume, R.; Molina, J. J.

    2014-01-01

    The aim of this study was to evaluate the normalized response speed (Vrn) of the knee musculature (flexor and extensor) in high competitive level volleyball players using tensiomyography (TMG) and to analyze the muscular response of the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), and biceps femoris (BF) in accordance with the specific position they play in their teams. One hundred and sixty-six players (83 women and 83 men) were evaluated. They belonged to eight teams in the Spanish women's superleague and eight in the Spanish men's superleague. The use of Vrn allows avoiding possible sample imbalances due to anatomical and functional differences and demands. We found differences between Vrn in each of the muscles responsible for extension (VM, RF, and VL) and flexion (BF) regardless of the sex. Normalized response speed differences seem to be larger in setters, liberos and outside players compared to middle blockers and larger in males when compared to females. These results of Vrn might respond to the differences in the physical and technical demands of each specific position, showing an improved balance response of the knee extensor and flexor musculature in male professional volleyball players. PMID:25003109

  20. Analysis of the response speed of musculature of the knee in professional male and female volleyball players.

    PubMed

    Rodríguez-Ruiz, D; Diez-Vega, I; Rodríguez-Matoso, D; Fernandez-del-Valle, M; Sagastume, R; Molina, J J

    2014-01-01

    The aim of this study was to evaluate the normalized response speed (Vrn) of the knee musculature (flexor and extensor) in high competitive level volleyball players using tensiomyography (TMG) and to analyze the muscular response of the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), and biceps femoris (BF) in accordance with the specific position they play in their teams. One hundred and sixty-six players (83 women and 83 men) were evaluated. They belonged to eight teams in the Spanish women's superleague and eight in the Spanish men's superleague. The use of Vrn allows avoiding possible sample imbalances due to anatomical and functional differences and demands. We found differences between Vrn in each of the muscles responsible for extension (VM, RF, and VL) and flexion (BF) regardless of the sex. Normalized response speed differences seem to be larger in setters, liberos and outside players compared to middle blockers and larger in males when compared to females. These results of Vrn might respond to the differences in the physical and technical demands of each specific position, showing an improved balance response of the knee extensor and flexor musculature in male professional volleyball players.

  1. An Intervention Based on Video Feedback and Questioning to Improve Tactical Knowledge in Expert Female Volleyball Players.

    PubMed

    Moreno, M Perla; Moreno, Alberto; García-González, Luis; Ureña, Aurelio; Hernández, César; Del Villar, Fernando

    2016-06-01

    This study applied an intervention program, based on video feedback and questioning, to expert female volleyball players to improve their tactical knowledge. The sample consisted of eight female attackers (26 ± 2.6 years old) from the Spanish National Volleyball Team, who were divided into an experimental group (n = 4) and a control group (n = 4). The video feedback and questioning program applied in the study was developed over eight reflective sessions and consisted of three phases: viewing of the selected actions, self-analysis and reflection by the attacker, and joint player-coach analysis. The attackers were videotaped in an actual game and four clips (situations) of each of the attackers were chosen for each reflective session. Two of the clips showed a correct action by the attacker, and two showed an incorrect decision. Tactical knowledge was measured by problem representation with a verbal protocol. The members of the experimental group showed adaptations in long-term memory, significantly improving their tactical knowledge. With respect to conceptual content, there was an increase in the total number of conditions verbalized by the players; with respect to conceptual sophistication, there was an increase in the indication of appropriate conditions with two or more details; and finally, with respect to conceptual structure, there was an increase in the use of double or triple conceptual structures. The intervention program, based on video feedback and questioning, in addition to on-court training sessions of expert volleyball players, appears to improve the athletes' tactical knowledge.

  2. Training volume and body composition as risk factors for developing jumper's knee among young elite volleyball players.

    PubMed

    Visnes, H; Bahr, R

    2013-10-01

    Training volume and body composition have been suggested as risk factors for jumper's knee among athletic youth, but research is lacking. The aim of this 4-year prospective cohort study was to examine the relationship between training and competition load, body composition, and risk for developing jumper's knee. Participants are elite volleyball players, aged 16-18 years. Training and competition load was recorded continuously and body composition semiannually. Jumper's knee was diagnosed on a standardized clinical examination. We recruited 141 healthy students (69 males and 72 females), and 28 developed jumper's knee (22 boys and six girls). In a multivariate analyses, boys had three to four times higher risk compared with girls. Volleyball training had an odds ratio (OR) 1.72 (1.18-2.53) for every extra hour trained, and match exposure was the strongest sports-related predictor for developing jumper's knee with an OR of 3.88 (1.80-8.40) for every extra set played per week. We did not detect any significant differences between the groups in body composition at the time of inclusion or in the change of body composition during the study period. Conclusion, male gender, a high volume of volleyball training and match exposure were risk factors for developing jumper's knee.

  3. Dominant vs. non-dominant shoulder morphology in volleyball players and associations with shoulder pain and spike speed.

    PubMed

    Challoumas, Dimitrios; Artemiou, Andreas; Dimitrakakis, Georgios

    2017-01-01

    The aims of our study were to compare the dominant (DOM) and non-dominant (NDOM) shoulders of high-level volleyball athletes and identify possible associations of shoulder adaptations with spike speed (SS) and shoulder pathology. A total of 22 male volleyball players from two teams participating in the first division of the Cypriot championship underwent clinical shoulder tests and simple measurements around their shoulder girdle joints bilaterally. SS was measured with the use of a sports speed radar. Compared with the NDOM side, the DOM scapula was more lateralised, the DOM dorsal capsule demonstrated greater laxity, the DOM dorsal muscles stretching ability was compromised, and the DOM pectoralis muscle was more lengthened. Players with present or past DOM shoulder pain demonstrated greater laxity in their DOM dorsal capsule, tightening of their DOM inferior capsule, and lower SS compared with those without shoulder pain. Dorsal capsule measurements bilaterally were significant predictors of SS. None of the shoulder measurements was associated with team roles or infraspinatus atrophy, while scapular lateralisation was more pronounced with increasing years of experience, and scapular antetilting was greater with increasing age. Adaptations of the DOM shoulder may be linked to pathology and performance. We describe simple shoulder measurements that may have the potential to predict chronic shoulder injury and become part of injury prevention programmes. Detailed biomechanical and large prospective studies are warranted to assess the validity of our findings and reach more definitive conclusions.

  4. Neovascularisation and pain in jumper's knee: a prospective clinical and sonographic study in elite junior volleyball players

    PubMed Central

    Gisslen, K; Alfredson, H; Peers, K

    2005-01-01

    Background: The nature of tendon neovascularisation associated with pain over time has not been studied. Objective: To prospectively study the patellar tendons in elite junior volleyball players. Methods: The patellar tendons in all students at the Swedish National Centre for high school volleyball were evaluated clinically and by ultrasonography (US) and Power Doppler (PD) sonography. Results: Altogether 120 patellar tendons were followed for 7 months. At inclusion, jumper's knee was diagnosed clinically in 17 patellar tendons. There were structural changes on US in 14 tendons, in 13 of which PD sonography showed neovascularisation. There were 70 clinically normal tendons with normal US and PD sonography, 24 clinically normal tendons with abnormal US but normal PD sonography, and nine clinically normal tendons with abnormal US and neovascularisation on PD sonography. At 7 month follow up, jumper's knee was diagnosed clinically and by US in 19 patellar tendons, in 17 of which there was neovascularisation. Three of nine clinically normal tendons with structural changes and neovascularisation at inclusion developed jumper's knee. Two of 24 tendons clinically normal at inclusion, with abnormal US but normal PD sonography, developed jumper's knee with abnormal US and neovascularisation on PD sonography. A total of 20 clinically normal tendons with normal US and PD sonography at inclusion developed structural tendon changes and 12 of these also developed neovascularisation. Conclusions: The clinical diagnosis of jumper's knee is most often associated with neovascularisation in the area with structural tendon changes. The finding of neovessels might indicate a deterioration of the condition. PMID:15976162

  5. Sensitivity of Physiological and Psychological Markers to Training Load Intensification in Volleyball Players

    PubMed Central

    Freitas, Victor H.; Nakamura, Fabio Y.; Miloski, Bernardo; Samulski, Dietmar; Bara-Filho, Mauricio G.

    2014-01-01

    The aim of this study was to test the sensitivity of; performance in the countermovement vertical Jump (CMJ); the Recovery and Stress Questionnaire for Athletes (RESTQ-Sport); the Total Quality Recovery Scale (TQR) and the creatine kinase (CK) to the deliberate intensification of volleyball training loads. For this purpose 8 athletes underwent a training period (FP) of 11 days of deliberate training load (TL) intensification followed by a second period (SP) of 14 days of reduction of loads (IT group). A further 8 athletes continued training with normal TL (NT group). Both groups were tested before the FP (baseline), after the FP and after the SP. The TL evaluated using the session rating of perceived exertion method (session-RPE) was higher after the FP compared to the SP, and higher in the IT group, compared to the NT group. The CMJ did not change in either group (p > 0.05). In the IT group, the RESTQ-Sport was altered after the FP compared to both the baseline and the SP (p < 0.05), while no change was observed in the NT group. In the IT group, the CK increased and the TQR decreased after the FP compared to both the baseline and after the SP and were higher and lower, respectively, than the NT group (p < 0.05). The results suggest that performance in the CMJ is not a sensitive variable to the fatigue caused by intensification of training loads during a pre-competitive period in volleyball, whereas CK, TQR and RESTQ-Sport were shown to be sensitive measures. Key Points The RESTQ-Sport and the TQR scales were sensitive to deliberate intensification of training loads during the pre-competitive period in volleyball athletes; The CK can be used to complement this monitoring; The CMJ performance was not sensitive to deliberate intensification of training loads in volleyball athletes. PMID:25177184

  6. Changes in strength and power qualities over two years in volleyball players transitioning from junior to senior national team.

    PubMed

    Sheppard, Jeremy M; Nolan, Emily; Newton, Robert U

    2012-01-01

    The purpose of this investigation was to examine the changes in performance indicators as they relate to strength and speed-strength development, over 2 years in a group of volleyball players who successfully transitioned from age group (U21) to senior national team in that time period. Sixteen male subjects (age: 18.5 ± 1.5 years, height: 2.00 ± 0.06 m, and weight: 88.4 ± 7.7 kg) participated in this 2-year longitudinal study. During the 24-month period of this investigation, all the subjects gained professional European contracts and also debuted with at least 1 senior national team match. These included, at a minimum, not only international friendly matches but also senior continental championships, World Championships, and the World Cup. Testing included 1 repetition maximum (1RM) and 3RM for the clean and squat, a maximum effort counter movement vertical jump (CMVJ), depth jump from a 0.35-m box (DJ), spike jump (with approach) (SPJ), and lower body speed-strength assessment with a body weight and body weight + 50% load. Large magnitude increases were observed for CMVJ, DJ, and SPJ over the 2-year period (d = 0.80, 0.82, and 0.94, respectively, p < 0.001). Unloaded (body weight) and loaded jump-squat performance also exhibited large improvements for all measured parameters, with very large increases in jump height in the unloaded (d = 1.21, p = 0.002) and loaded jump squat (d = 1.346, p < 0.001). Very large magnitude changes in 1RM Clean and 3RM Squat (d = 1.56 and 2.21, respectively, p < 0.001) were observed over the 2-year investigation period, and a large increase (d = 1.18, p < 0.001) in the lean mass ratio (mass/sum skinfolds). To progress from junior representation to senior national team, volleyball players must increase their CMVJ and SPJ. This is best accomplished through increasing lean mass, reducing fat mass, improving strength and speed strength, and developing high levels of stretch-load tolerance in stretch-shorten cycle activity.

  7. Differentiating Experts' Anticipatory Skills in Beach Volleyball

    ERIC Educational Resources Information Center

    Canal-Bruland, Rouwen; Mooren, Merel; Savelsbergh, Geert J. P.

    2011-01-01

    In this study, we examined how perceptual-motor expertise and watching experience contribute to anticipating the outcome of opponents' attacking actions in beach volleyball. To this end, we invited 8 expert beach volleyball players, 8 expert coaches, 8 expert referees, and 8 control participants with no beach volleyball experience to watch videos…

  8. Acute effects of Yo-Yo intermittent recovery test level 1 (Yo-YoIR1) on hemorheological parameters in female volleyball players.

    PubMed

    Kilic-Toprak, Emine; Yapici, Ayşegül; Kilic-Erkek, Ozgen; Koklu, Yusuf; Tekin, Volkan; Alemdaroglu, Utku; Bor-Kucukatay, Melek

    2015-07-16

    In the present study, we investigated possible alterations in red blood cell (RBC) deformability, plasma and whole blood viscosities (WBV) and hematological parameters in response to Yo-Yo intermittent recovery test level 1 (Yo-YoIR1) which is currently used to assess endurance performance, in female volleyball players. Eight volleyball player volunteers from Pamukkale University (mean age19,9 ± 2,2 years; mean body height 177.5 ± 1.99 cm; mean body mass index 21.66 ± 0.64 kg/m2) participated to the study. Blood samples were collected before and immediately after test. Red blood cell (RBC) deformability was determined by ektacytometer, plasma and whole blood viscosities (WBV) by a cone-plate rotational viscometer. Hematological parameters were determined using an electronic hematology analyzer. The Yo-YoIR1 applied, induced acute increments in WBV at native hematocrit (Hct) measured at a shear rate of 150 s-1 and 375 s-1, RBC deformability and WBC count. The results of the current study indicate that, the Yo-Yo IR1 test used to determine physical capacity of the player, by resulting in increments in RBC deformability contributes blood flow and thus, athletic performance of the individual.

  9. Modifying spike jump landing biomechanics in female adolescent volleyball athletes using video and verbal feedback.

    PubMed

    Parsons, Joanne L; Alexander, Marion J L

    2012-04-01

    Landing awkwardly from a jump is a common mechanism of injury for the anterior cruciate ligament (ACL) of the knee. Augmented feedback, such as verbal or visual instruction, has been shown to cause an immediate, positive change in landing biomechanics in a laboratory setting. No data exist on the longer term effects of feedback on jump landing biomechanics in a sports-specific setting. The purpose of this study was to explore whether providing video and verbal feedback to adolescent (12-14 years old) female volleyball athletes would improve their landing technique. Trunk and lower extremity kinematic variables were measured in 19 participants before a feedback session was provided to the intervention group (IG). Follow-up kinematic measurements of the IG were taken immediately postintervention, and again after 2 and 4 weeks. Two-way repeated measures analysis of variance (ANOVA) was used to compare the IG with a control group (CG), who received no feedback. The IG (n = 10) demonstrated increased maximal hip and trunk flexion compared with the CG (n = 9) at week 4 (p ≤ 0.05). One-way repeated measures ANOVA was used to determine if changes were evident within the IG over time. Ankle dorsiflexion, right knee and hip flexion, and trunk flexion changed significantly (p ≤ 0.05) over the 4-week period. Augmented feedback appeared to produce a positive change in landing biomechanics in adolescent female volleyball athletes performing a sports-specific skill. Courtside video and verbal feedback may present a relatively simple, cost-effective method of introducing one component of a comprehensive ACL injury prevention program at a young age.

  10. The Effect of Submaximal Exercise Preceded by Single Whole-Body Cryotherapy on the Markers of Oxidative Stress and Inflammation in Blood of Volleyball Players

    PubMed Central

    Mila-Kierzenkowska, Celestyna; Szpinda, Michał; Augustyńska, Beata; Woźniak, Bartosz

    2013-01-01

    The aim of the study was to determine the effect of single whole-body cryotherapy (WBC) session applied prior to submaximal exercise on the activity of antioxidant enzymes, the concentration of lipid peroxidation products, total oxidative status, and the level of cytokines in blood of volleyball players. The study group consisted of 18 male professional volleyball players, who were subjected to extremely cold air (−130°C) prior to exercise performed on cycloergometer. Blood samples were taken five times: before WBC, after WBC procedure, after exercise preceded by cryotherapy (WBC exercise), and before and after exercise without WBC (control exercise). The activity of catalase statistically significantly increased after control exercise. Moreover, the activity of catalase and superoxide dismutase was lower after WBC exercise than after control exercise (P < 0.001). After WBC exercise, the level of IL-6 and IL-1β was also lower (P < 0.001) than after control exercise. The obtained results may suggest that cryotherapy prior to exercise may have some antioxidant and anti-inflammatory properties. The relations between the level of studied oxidative stress and inflammatory markers may testify to the contribution of reactive oxygen species in cytokines release into the blood system in response to exercise and WBC. PMID:24489985

  11. Comparison of whole-body vibration exercise and plyometric exercise to improve isokinetic muscular strength, jumping performance and balance of female volleyball players

    PubMed Central

    Kim, Yong-Youn; Park, Si-Eun

    2016-01-01

    [Purpose] The purpose of this study was to assess the effect of whole-body vibration exercise and plyometric exercise on female volleyball players. [Subjects and Methods] Subjects were randomly allocated to two exercise groups (whole-body vibration exercise group and plyometric exercise group). The exercise was conducted three times each week for 8 weeks. Isokinetic muscular strength, jumping performance, and balance were measured before starting the exercise and after finishing the 8 weeks of exercise. [Results] Measurements of isokinetic muscular strength revealed that the whole-body vibration exercise group showed significant increase after the exercise. However, the plyometric exercise group had no significant increase in lumbar flexion, extension, and knee flexion. Measurements of vertical jumping revealed that, the whole-body vibration exercise group had no significant increase after the exercise. However, the plyometric exercise group showed significant increase. Measurements of balance revealed that, the whole-body vibration exercise group showed significant increase. However, the plyometric exercise group showed no significant increase. [Conclusion] Although both whole-body vibration and plyometric exercises are effective intervention methods, the two methods have different effects on the improvement of isokinetic muscular strength, jumping performance, and balance of female volleyball players. PMID:27942136

  12. Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players

    PubMed Central

    Young, M; Cook, J; Purdam, C; Kiss, Z; Alfredson, H

    2005-01-01

    Background: Conservative treatment of patellar tendinopathy has been minimally investigated. Effective validated treatment protocols are required. Methods: This was a prospective randomised controlled trial of 17 elite volleyball players with clinically diagnosed and imaging confirmed patellar tendinopathy. Participants were randomly assigned to one of two treatment groups: a decline group and a step group. The decline group were required to perform single leg squats on a 25° decline board, exercising into tendon pain and progressing their exercises with load. The step group performed single leg squats on a 10 cm step, exercising without tendon pain and progressing their exercises with speed then load. All participants completed a 12 week intervention programme during their preseason. Outcome measures used were the Victorian Institute of Sport Assessment (VISA) score for knee function and 100 mm visual analogue scale (VAS) for tendon pain with activity. Measures were taken throughout the intervention period and at 12 months. Results: Both groups had improved significantly from baseline at 12 weeks and 12 months. Analysis of the likelihood of a 20 point improvement in VISA score at 12 months revealed a greater likelihood of clinical improvements in the decline group than the step group. VAS scores at 12 months did not differ between the groups. Conclusions: Both exercise protocols improved pain and sporting function in volleyball players over 12 months. This study indicates that the decline squat protocol offers greater clinical gains during a rehabilitation programme for patellar tendinopathy in athletes who continue to train and play with pain. PMID:15665207

  13. The impact of physically demanding work of basketball and volleyball players on the risk for patellar tendinopathy and on work limitations.

    PubMed

    van der Worp, H; Zwerver, J; Kuijer, P P F M; Frings-Dresen, M H W; van den Akker-Scheek, I

    2011-01-01

    Patellar tendinopathy is a common injury in jumping athletes. Little is known about work-related etiological factors for patellar tendinopathy and related work limitations. The aim of this study was to identify work-related etiological factors for patellar tendinopathy and to determine the relation between patellar tendinopathy and work limitations. Basketball and volleyball players between 18 and 35 years were invited to complete an online-questionnaire concerning knee complaints, etiological risk factors for patellar tendinopathy and related work limitations. A total of 1505 subjects were included in the analysis. Risk factors for patellar tendinopathy were gender and heavy physically demanding work. The odds for having patellar tendinopathy were significantly higher for heavy physically demanding occupations compared to mentally demanding occupations. 30% of subjects with patellar tendinopathy with a physically demanding job reported to be impaired in their work and 17% reported to be less productive. Basketball and volleyball players with heavy physically demanding work seem to have an increased risk for developing patellar tendinopathy. This finding has important clinical relevance in the treatment of this injury. Working activities should be adjusted in order to reduce the total load on the patellar tendon and help prevention and recovery.

  14. Postural Variables in Girls Practicing Volleyball

    ERIC Educational Resources Information Center

    Grabara, Malgorzata; Hadzik, Andrzej

    2009-01-01

    Study aim: To assess body posture of young female volleyball players in relation to their untrained mates. Material and methods: A group of 42 volleyball players and another of 43 untrained girls, all aged 13-16 years were studied with respect to their body posture indices by using computer posturography. Spinal angles and curvatures were…

  15. Landing Techniques in Beach Volleyball

    PubMed Central

    Tilp, Markus; Rindler, Michael

    2013-01-01

    The aims of the present study were to establish a detailed and representative record of landing techniques (two-, left-, and right-footed landings) in professional beach volleyball and compare the data with those of indoor volleyball. Beach volleyball data was retrieved from videos taken at FIVB World Tour tournaments. Landing techniques were compared in the different beach and indoor volleyball skills serve, set, attack, and block with regard to sex, playing technique, and court position. Significant differences were observed between men and women in landings following block actions (χ2(2) = 18.19, p < 0.01) but not following serve, set, and attack actions. Following blocking, men landed more often on one foot than women. Further differences in landings following serve and attack with regard to playing technique and position were mainly observed in men. The comparison with landing techniques in indoor volleyball revealed overall differences both in men (χ2(2) = 161.4, p < 0.01) and women (χ2(2) = 84.91, p < 0.01). Beach volleyball players land more often on both feet than indoor volleyball players. Besides the softer surface in beach volleyball, and therefore resulting lower loads, these results might be another reason for fewer injuries and overuse conditions compared to indoor volleyball. Key Points About 1/3 of all jumping actions in beach volleyball result in a landing on one foot. Especially following block situations men land on one foot more often than women. Landing techniques are related to different techniques and positions. Landings on one foot are less common in beach volleyball than indoor volleyball. This could be a reason for fewer injuries and overuse conditions. PMID:24149150

  16. Effect of cold water immersion performed on successive days on physical performance, muscle damage, and inflammatory, hormonal, and oxidative stress markers in volleyball players.

    PubMed

    de Freitas, Victor H; Ramos, Solange P; Bara-Filho, Maurício G; Freitas, Daniel G S; Coimbra, Danilo R; Cecchini, Rubens; Guarnier, Flávia A; Nakamura, Fábio Y

    2017-03-08

    The aim of this study was to investigate the effects of daily cold water immersion (CWI) on physical performance, muscle damage, and inflammatory, hormonal, and oxidative stress markers in volleyball. Six players were submitted to CWI and six players to a placebo, during 5 training days. Thigh circumference, squat jump, and agility were measured on the 1, 3 and 6 days. On the 1 and 6 days, blood and saliva were collected for analysis of oxidative stress, muscle damage, and inflammatory and hormonal levels. Muscle soreness and countermovement jump were quantified daily. The physical performance comparisons did not present differences and the only between group comparison with a large effect size (ES = -1.39) was in Δ% between day 1 and day 2 for CMJ. DOMS and creatine kinase increased in both groups and the ES of between group comparisons of Δ% between moments were not more than moderate. Thigh circumference increased only in the placebo group (P = 0.04) and the ES of the between group comparisons of Δ% between moments was large (1.53). No differences were found in oxidative stress, or inflammatory markers. Cortisol decreased only in the CWI-group (P < 0.05) and the ES of the between group comparisons of Δ% between moments of the testosterone/cortisol ratio (- 1.94) and IGF-1 (- 1.34) were large. Despite the positive effects of daily CWI on muscle edema and hormonal status, the limited effects of CWI on performance, muscle damage, inflammation markers, and ROS mediators signal the unimportance of the daily practice of this recovery method in volleyball players.

  17. Iron supplementation prevents a decline in iron stores and enhances strength performance in elite female volleyball players during the competitive season.

    PubMed

    Mielgo-Ayuso, Juan; Zourdos, Michael C; Calleja-González, Julio; Urdampilleta, Aritz; Ostojic, Sergej

    2015-06-01

    The primary aim of this study was to examine the effects of 11 weeks of iron supplementation on hematological and strength markers in elite female volleyball players. Twenty-two volleyball players (aged 27.0 ± 5.6 years) from 2 Spanish First National League teams participated and were counterbalanced into 1 of 2 groups based upon iron status: (i) control group (CG, n = 11); or (ii) iron treatment group (ITG, n = 11), which received 325 mg/day of ferrous sulphate daily. Subjects performed their team's regimen of training or match play every day. Both groups were tested for hematological and strength levels at 2 points: (i) baseline (T0, before preseason) and (ii) 11 weeks later (T11, post-testing). Hematological parameters were serum iron (sFe), serum ferritin (FER), transferrin saturation index (TSI), and hemoglobin (Hb); strength assessments were bench press, military press, half-squat, power clean, clean and jerk, and pull-over. CG experienced a significant decrease (p < 0.05) for sFe (T0, 112.7 ± 31.5; T11, 69.0 ± 20.5 μg·dL(-1); -33.9%), FER (T0, 60.2 ± 28.6; T11, 38.2 ± 16.4 ng·mL(-1); -34.6%), TSI (T0, 29.4% ± 9.5%; T11, 17.4% ± 5.1%; -35.3%), and Hb (T0, 14.1 ± 1.0; T11, 13.0 ± 0.8 g·L(-1); -7.44%); however, ITG experienced no changes (p > 0.05). Consequently, in ITG all hematological parameters were significantly greater (p < 0.05) than CG at T11. There was greater (p < 0.05) percent increase in the clean and jerk (CG: +5.1% ± 20.9 vs. ITG: +29.0% ± 21.3%), power clean (CG: -5.8% ± 30.3% vs. ITG: +44.6% ± 56.6%), and total mean strength (CG: +10.9% ± 3.2% vs. ITG: +26.2% ± 3.6%) in ITG. Our findings suggest that oral iron supplementation prevents iron loss and enhances strength in female volleyball players during the competitive season.

  18. Sagittal Spinal Morphology in Highly Trained Adolescent Tennis Players

    PubMed Central

    Muyor, José M.; Sánchez-Sánchez, Estefanía; Sanz-Rivas, David; López-Miñarro, Pedro A.

    2013-01-01

    Sports with a predominance of forward-bending and extension postures have been associated with alterations in the sagittal spinal curvatures and greater risk of spinal injury. Because, the tennis players adopt these postures, the aims of this study were: 1) to describe spinal curvatures and pelvic tilt in male and female highly trained adolescent tennis players during relaxed standing posture and with thoracic spine corrected (in prone lying on the floor); and 2) to determine the frequency of thoracic hyperkyphosis and lumbar hypo/hyper lordosis in these postures. Forty adolescent tennis players (24 male and 16 female) aged 13-18 years, participated voluntarily in this study. The Spinal Mouse system was used to measure sagittal spinal curvatures and pelvic tilt. The mean values in the relaxed standing posture were 43.83° ± 7.87° (thoracic kyphosis), - 27.58° ± 7.01° (lumbar lordosis), and 13.38° ± 5.57° (pelvic tilt) for male tennis players, respectively; and 36.13° ± 6.69° (thoracic kyphosis), - 32.69° ± 5.06° (lumbar lordosis), 20.94° ± 5.36° (pelvic tilt) for female tennis players (p < 0.05 between genders in all spinal parameters). The male and female tennis players showed a frequency of 62.5% and 93.8% (p = 0.032) for neutral thoracic kyphosis, and 83.3% and 93.8% (p = 0.062) in neutral lumbar lordosis, respectively. In conclusion, due to the high percentage of neutral spinal curvatures in both male and female tennis players, to practice tennis in these levels does not alter sagittal spinal morphology in the relaxed standing posture in adolescent highly trained tennis players. Key Points This study evaluated thoracic and lumbar spinal curvatures and pelvic tilt during several postures in young highly trained tennis players. Female tennis players showed statistically significant greater anterior pelvic tilt, lumbar lordosis and lower thoracic kyphosis than male tennis players. The high percentage of neutral thoracic kyphosis and lumbar

  19. Kinesiology Taping does not Modify Electromyographic Activity or Muscle Flexibility of Quadriceps Femoris Muscle: A Randomized, Placebo-Controlled Pilot Study in Healthy Volleyball Players

    PubMed Central

    Halski, Tomasz; Dymarek, Robert; Ptaszkowski, Kuba; Słupska, Lucyna; Rajfur, Katarzyna; Rajfur, Joanna; Pasternok, Małgorzata; Smykla, Agnieszka; Taradaj, Jakub

    2015-01-01

    Background Kinesiology taping (KT) is a popular method of supporting professional athletes during sports activities, traumatic injury prevention, and physiotherapeutic procedures after a wide range of musculoskeletal injuries. The effectiveness of KT in muscle strength and motor units recruitment is still uncertain. The objective of this study was to assess the effect of KT on surface electromyographic (sEMG) activity and muscle flexibility of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) muscles in healthy volleyball players. Material/Methods Twenty-two healthy volleyball players (8 men and 14 women) were included in the study and randomly assigned to 2 comparative groups: “kinesiology taping” (KT; n=12; age: 22.30±1.88 years; BMI: 22.19±4.00 kg/m2) in which KT application over the RF muscle was used, and “placebo taping” (PT; n=10; age: 21.50±2.07 years; BMI: 22.74±2.67 kg/m2) in which adhesive nonelastic tape over the same muscle was used. All subjects were analyzed for resting sEMG activity of the VL and VM muscles, resting and functional sEMG activity of RF muscle, and muscle flexibility of RF muscle. Results No significant differences in muscle flexibility of the RF muscle and sEMG activity of the RF, VL, and VM muscles were registered before and after interventions in both groups, and between the KT and PT groups (p>0.05). Conclusions The results show that application of the KT to the RF muscle is not useful to improve sEMG activity. PMID:26232122

  20. Adolescents Risky MP3-Player Listening and Its Psychosocial Correlates

    ERIC Educational Resources Information Center

    Vogel, Ineke; Brug, Johannes; Van Der Ploeg, Catharina P. B.; Raat, Hein

    2011-01-01

    Analogue to occupational noise-induced hearing loss, MP3-induced hearing loss may be evolving into a significant social and public health problem. To inform prevention strategies and interventions, this study investigated correlates of adolescents' risky MP3-player listening behavior primarily informed by protection motivation theory. We invited…

  1. Adolescents risky MP3-player listening and its psychosocial correlates.

    PubMed

    Vogel, Ineke; Brug, Johannes; Van der Ploeg, Catharina P B; Raat, Hein

    2011-04-01

    Analogue to occupational noise-induced hearing loss, MP3-induced hearing loss may be evolving into a significant social and public health problem. To inform prevention strategies and interventions, this study investigated correlates of adolescents' risky MP3-player listening behavior primarily informed by protection motivation theory. We invited 1687 adolescents (12- to 19-year old) of Dutch secondary schools to complete questionnaires about their MP3-player listening, sociodemographic characteristics and presumed psychosocial determinants of MP3-player listening. Of all participants, 90% reported listening to music through earphones on MP3 players; 28.6% were categorized as listeners at risk for hearing loss due to estimated exposure of 89 dBA for ≥1 hour per day. Compared with listeners not at risk for hearing loss, listeners at risk were more likely not to live with both parents, to experience rewards of listening to high-volume levels, to report a high habit strength related to risky MP3 listening, and were less likely to be motivated to protect their hearing. Habit strength was the strongest correlate of risky listening behavior, suggesting that voluntary behavior change among adolescents might be difficult to achieve and that a multiple strategy approach may be needed to prevent MP3-induced hearing loss.

  2. Light-emitting diode therapy (LEDT) before matches prevents increase in creatine kinase with a light dose response in volleyball players.

    PubMed

    Ferraresi, Cleber; Dos Santos, Ricardo Vinicius; Marques, Guilherme; Zangrande, Marcelo; Leonaldo, Roberley; Hamblin, Michael R; Bagnato, Vanderlei Salvador; Parizotto, Nivaldo Antonio

    2015-05-01

    Low-level laser (light) therapy (LLLT) has been applied over skeletal muscles before intense exercise (muscular pre-conditioning) in order to reduce fatigue and muscle damage (measured by creatine kinase, CK) in clinical trials. However, previous exercise protocols do not exactly simulate the real muscle demand required in sports. For this reason, the aim of this randomized and double-blind placebo-controlled trial was to investigate whether light-emitting diode therapy (LEDT) applied over the quadriceps femoris muscles, hamstrings, and triceps surae of volleyball players before official matches could prevent muscle damage (CK) with a dose response, establishing a therapeutic window. A professional male volleyball team (12 athletes) was enrolled in this study, and LEDT was applied before 4 matches during a national championship. LEDT used an array of 200 light-emitting diodes (LEDs) arranged in 25 clusters of 4 infrared LEDs (850 ± 20 nm; 130 mW) and 25 clusters of 4 red LEDs (630 ± 10 nm; 80 mW). Athletes were randomized to receive one of four different total doses over each muscle group in a double-blind protocol: 105 J (20 s), 210 J (40 s), 315 J (60 s), and placebo (no light for 30 s). CK in blood was assessed 1 h before and 24 h after each match. LEDT at 210 J avoided significant increases in CK (+10 %; P = 0.993) as well as 315 J (+31 %, P = 0.407). Placebo (0 J) allowed a significant increase in CK (+53 %; P = 0.012) as well as LEDT at 105 J (+59 %; P = 0.001). LEDT prevented significant increases of CK in blood in athletes when applied before official matches with a light dose response of 210-315 J, suggesting athletes might consider applying LEDT before competition.

  3. Iliopsoas haematoma in an adolescent Taekwondo player.

    PubMed

    Maffulli, N; So, W S; Ahuja, A; Chan, K M

    1996-01-01

    A 16-year-old male Taekwondo player was admitted with a 1-day history of right groin pain and a palpable mass in the right lower abdominal quadrant following a Taekwondo training session. No history of direct trauma was given, but the pain followed a high inward-to-outward kick. The patient was not on any medication, and tumour and infection were excluded. A high-resolution real-time ultrasound scan identified a well-defined, hyperechoic, heterogeneous mass in the substance of the right iliopsoas muscle, compatible with a collection of partially clotted blood, confirming the clinical diagnosis of iliopsoas haematoma. After conservative treatment the patient resumed training and is now fully asymptomatic.

  4. Word play, ritual insult, and volleyball in Peru.

    PubMed

    Perez, Justin

    2011-01-01

    Many gay men in the popular sectors of Lima, Peru participate in vóley callejero, or street volleyball. The ethnographic data presented in this article describes verbal and corporal mechanisms through which gay identity emerges within the particular context of the street volleyball game, ultimately highlighting the contextual nature of identity. The volleyball players are not just hitting a ball back and forth, they are engaging in a meaningful activity that illuminates intersections of language, sexuality, and identity. Through the manipulation of the street into a volleyball court, the volleyball players create a space conducive to the articulation of particular verbal and embodied practices that index gay identity. The challenge to the regulations of "proper" volleyball through the practice of ritual insulting and the cultivation of gay volleyball technique are playful reconfigurations of gendered practices prominent in the sites where fieldwork was carried out.

  5. [Injuries in male and female adolescent soccer players].

    PubMed

    Schneider, A S; Mayer, H M; Geißler, U; Rumpf, M C; Schneider, C

    2013-03-01

    This study addresses the epidemiology of injuries in adolescent male and female soccer players in Germany. Therefore, the purpose of the study was to analyse the injuries in male and female youth soccer players in Germany. This study was designed as a cross-sectional web-based survey. From March until December 2011 we investigated 1110 soccer players (male n = 841; female n = 269) aged 12 - 19 years (15.0 ± 2.0 years) from 60 clubs in Southern Germany. A total of 664 (79 %) of the 841 boys and 67 (25 %) of the 269 girls reported being injured due to soccer. The total number of injuries was 2373. Respectively the frequency of injury was 2.85 in boys and 7.10 in girls. The lower extremities were affected in 70 % of all reported cases. Strains were the most common injuries in the lower and upper extremities (35 %). The boys reported in 51.5 % of all injuries that the injury was non-contact in nature. In contrast, 52.1 % of the injuries in girls were reported as contact injuries. Similar amounts of injuries were observed in training versus games for both genders. Prevention procedures, such as a thorough warm-up, should be implemented before every game and training to reduce the risk of injury.

  6. Grape Seed Extract Supplementation and the Effects on the Biomarkers of Oxidative Stress and Metabolic Profiles in Female Volleyball Players: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

    PubMed Central

    Taghizadeh, Mohsen; Malekian, Elaheh; Memarzadeh, Mohammad Reza; Mohammadi, Ali Akbar; Asemi, Zatollah

    2016-01-01

    Background Only limited data are available for evaluating the effects of the administration of grape seed extract (GSE) on the metabolic status of female volleyball players. Objectives This study was conducted to determine the effects of GSE administration on the metabolic status of female volleyball players. Methods This randomized, double-blind, placebo-controlled clinical trial was performed among 40 female volleyball players. The subjects were randomly divided into two groups, with members of the test group (n = 20) taking 300 mg of GSE twice a day for eight weeks and members of the control group (n = 20) taking a placebo pearl for the same period. Fasting blood samples were taken before and after the eight-week intervention period in order to determine the related variables. Results Supplementation with GSE resulted in a significant rise in the plasma glutathione (GSH) level (+265.5 ± 344.2 vs. +2.2 ± 378.2 µmol/L, P = 0.02), as well as a significant decrease in the malondialdehyde (MDA) level (-1.4 ± 2.0 vs. -0.2 ± 1.2 µmol/L, P = 0.01) when compared to the placebo group. In addition, when compared to the group that received the placebo, the subjects who received GSE had significantly decreased serum insulin concentrations (-23.4 ± 23.4 vs. +1.8 ± 25.2 pmol/L, P = 0.002), a decreased homeostasis model of assessment for insulin resistance (HOMA-IR) (-0.7 ± 0.7 vs. +0.2 ± 0.9, P = 0.002), and an increased quantitative insulin sensitivity check index (QUICKI) (+0.01 ± 0.01 vs. -0.01 ± 0.02, P = 0.03). The administration of GSE had no significant effects on creatine phosphokinase (CPK), total antioxidant capacity (TAC), nitric oxide (NO), fasting plasma glucose (FPG), and lipid concentrations when compared with the administration of the placebo. However, after controlling for baseline NO levels, age, and baseline BMI, the changes in the plasma NO concentrations were significantly different between the two groups. Conclusions In conclusion, taking GSE

  7. Running activity profile of adolescent tennis players during match play.

    PubMed

    Hoppe, Matthias W; Baumgart, Christian; Bornefeld, Jutta; Sperlich, Billy; Freiwald, Jürgen; Holmberg, Hans-Christer

    2014-08-01

    The aims of this study were (1) to assess the running activities of adolescent tennis players during match play with respect to velocity, acceleration, and deceleration; (2) to characterize changes in these activities during the course of a match; and (3) to identify potential differences between winners and losers. Twenty well-trained adolescent male athletes (13 ± 1 y) played one simulated match each (giving a total of 10 matches), during which distances covered at different velocity categories (0 to < 1, 1 to < 2, 2 to < 3, 3 to < 4, and ≥ 4 m·s(-1)) and number of running activities involving high velocity (≥ 3 m·s(-1)), acceleration (≥ 2 m·s(-2)), and deceleration (≤ -2 m·s(-2)) were monitored using a global positioning system (10 Hz). Heart rate was also assessed. The total match time, total distance covered, peak velocity, and mean heart rate were 81.2 ± 14.6 min, 3362 ± 869 m, 4.4 ± 0.8 m·s(-1), and 159 ± 12 beats·min(-1), respectively. Running activities involving high acceleration (0.6 ± 0.2 n·min(-1)) or deceleration (0.6 ± 0.2 n·min(-1)) were three times as frequent as those involving high velocity (0.2 ± 0.1 n·min(-1)). No change in the pattern of running activities (P ≥ .13, d ≤ 0.39) and no differences between winners and losers (P ≥ .22, d ≤ 0.53) were evident during match play. We conclude that training of well-trained adolescent male tennis players need not focus on further development of their running abilities, since this physical component of multifactorial tennis performance does not change during the course of a match and does not differ between the winners and losers.

  8. Left atrial remodelling in competitive adolescent soccer players.

    PubMed

    D'Ascenzi, F; Cameli, M; Lisi, M; Zacà, V; Natali, B; Malandrino, A; Benincasa, S; Catanese, S; Causarano, A; Mondillo, S

    2012-10-01

    Left atrial (LA) enlargement and improved myocardial diastolic properties are a component of athlete's heart. We performed a longitudinal study involving adolescent athletes to investigate the impact of training on LA remodelling and diastolic function. 21 competitive adolescent soccer players were enrolled and engaged in an 8-month training program. Echocardiographic analysis was performed at baseline, after 4 and 8 months. We assessed diastolic function by Doppler tissue imaging and we analyzed LA adaptations by 2D speckle-tracking echocardiography. After 4 months, LA mean volume index significantly increased (Δ=5.47 ± 4.38 mL/m2, p ≤ 0.0001). After 8 months, a further increase occurred (Δ=8.95 ± 4.47 mL/m2, p ≤ 0.0001). A higher E velocity (p=0.001; p=0.001), a greater E/A ratio (p=0.002; p=0.0009), a higher e' peak (p= 0.005; p=0.001), and a greater e'/a' ratio (p=0.01; p=0.0006) were observed at 4 and at 8 months, respectively. E/e' ratio significantly decreased after 8 months (p ≤ 0.005). Global peak atrial longitudinal strain and global peak atrial contraction strain values significantly decreased after 8 months (p=0.0004, p=0.01, respectively). An 8-month training program is associated with LA dimensional and functional training-specific adaptations in competitive adolescent soccer players. Myocardial diastolic properties can improve after training also in subjects already presenting with features of athlete's heart.

  9. Collaboration with Sport Psychologists as Viewed by Female Volleyball Junior Teams

    ERIC Educational Resources Information Center

    Otrebski, Wojciech; Rutkowska, Katarzyna

    2008-01-01

    Study aim: To determine the need of female junior volleyball players to collaborate with a psychologist, considering previous sport career of those players. Material and methods: A group of 78 female volleyball players aged 14-17 years from 7 top Polish junior teams participated in the study. They were requested to fill questionnaires on their…

  10. Differentiating experts' anticipatory skills in beach volleyball.

    PubMed

    Cañal-Bruland, Rouwen; Mooren, Merel; Savelsbergh, Geert J P

    2011-12-01

    In this study, we examined how perceptual-motor expertise and watching experience contribute to anticipating the outcome of opponents' attacking actions in beach volleyball. To this end, we invited 8 expert beach volleyball players, 8 expert coaches, 8 expert referees, and 8 control participants with no beach volleyball experience to watch videos of attack sequences that were occluded at three different times and to predict the outcome of these situations. Results showed that expert players and coaches (who were both perceptual-motor experts) outperformed the expert referees (who were watching experts but did not have the same motor expertise) and the control group in the latest occlusion condition (i.e., at spiker-ball contact). This finding suggests that perceptual-motor expertise may contribute to successful action anticipation in beach volleyball.

  11. Signs and symptoms of temporomandibular disorders in adolescent violin players.

    PubMed

    Kovero, O; Könönen, M

    1996-08-01

    Signs and symptoms of temporomandibular disorders (TMDs) and the frequency of radiologically observed abnormalities in the condyles of temporomandibular joints (TMJs) of adolescent violin players (VP group) were investigated in a group of 31 music students and in their age- and sex-matched controls (C group). All subjects underwent a routine clinical stomatognathic examination, a standardized interview, and radiography of the condyles. The VP group reported a higher frequency of the subjective symptoms: pain in the TMJ when chewing, a feeling of stiffness in the TMJ, and clenching of the teeth. Clinically, the VP group showed a greater range of maximal protrusion and of maximal laterotrusion to the right, and a greater frequency of deviation to the right on opening. They also showed more palpatory tenderness in the masticatory muscles and pain in the TMJ on maximal opening. The number of playing years and the number of weekly playing hours correlated with several signs and symptoms of TMDs. In terms of radiologic findings in the condyles of the TMJs there was no difference between the groups. It is concluded that intense violin playing may have a predisposing role in the etiology of TMDs in adolescence.

  12. [Causes and prevention of typical volleyball injuries].

    PubMed

    Hell, H; Schönle, C

    1985-01-01

    A survey conducted among 224 volleyball players in the German Federal League revealed a high number of serious injuries. The upper ankle joint (55.1% of all serious injuries) and the fingers (22.4%) were most commonly affected. The principal cause of the accidents was a collision with an opponent at the net. There is a close relationship between the player's position, the part he plays in the game and the frequency of injury. Aside from other measures a change of one of the international volleyball rules would represent a suitable method of preventing such injuries.

  13. The Effects of Opposition and Gender on Knee Kinematics and Ground Reaction Force during Landing from Volleyball Block Jumps

    ERIC Educational Resources Information Center

    Hughes, Gerwyn; Watkins, James; Owen, Nick

    2010-01-01

    The aim of this study was to examine the effect of opposition and gender on knee kinematics and ground reaction force during landing from a volleyball block jump. Six female and six male university volleyball players performed two landing tasks: (a) an unopposed and (b) an opposed volleyball block jump and landing. A 12-camera motion analysis…

  14. Bone properties in child and adolescent male hockey and soccer players.

    PubMed

    Falk, Bareket; Braid, Sarah; Moore, Michael; Yao, Matthew; Sullivan, Phil; Klentrou, Nota

    2010-07-01

    Children and adolescents who train extensively in high-impact, weight-bearing activities have enhanced bone mineral density. The purpose of this study was to evaluate bone strength, as reflected by quantitative ultrasound (QUS, Sunlight Omniscence), of child (10-12 yrs old) and adolescent (14-16 yrs old) male soccer and hockey players in comparison with age-matched controls. The groups included 30 child (CH) and 31 adolescent (AH) hockey players, 26 child (CS) and 30 adolescent (AS) soccer players, as well as 34 child (CC) and 31 adolescent (AC) healthy, non-athletic, age-matched controls. All athletes trained at an elite level year-round, with no difference in training volume between groups. Ultrasound speed of sound (SOS) was measured at the distal-radius and mid-tibia. In both age groups, hockey players were the heaviest and had the highest fat-free mass. No differences were found among groups in total energy intake, calcium or vitamin D intake. Radial and tibial SOS increased with age. Hockey players had higher radial SOS in both age groups (children: CH:3763+/-74, CS:3736+/-77, CC:3721+/-88 m/s; adolescents: AH:3809+/-105, AS:3767+/-85, AC:3760+/-94 m/s). Tibial SOS was higher in soccer players compared with controls. In spite of the higher body mass and fat-free mass in hockey players, their tibial SOS was similar to the non-athletes in both age groups. These findings support previous suggestions of sport-specific effects on bone strength. However, they need to be corroborated with longitudinal or prospective intervention studies.

  15. Assessment of isokinetic muscle function in Korea male volleyball athletes

    PubMed Central

    Kim, Chang-Gyun; Jeoung, Bog Ja

    2016-01-01

    Volleyball players performed numerous repetitions of spike actions, which uses and requires strong and explosive force, and control of the muscles of the shoulder, lower back, and legs. Muscle imbalance is one of the main causes of sport injuries. The purpose of this study was to assess isokinetic muscle functions in male volleyball players. We thus aim to accurately evaluate their muscle functions, and identify the best training strategy to achieve optimal muscle strength balance in future training programs. The participants in this study consisted of 14 male volleyball players. Muscle strength was measured using the isokinetic dynamometer. Muscle strength was evaluated in terms of peak torque and average power, calculated from five repeated measurements at an angular speed of 60°/sec. Three players who were left attackers showed shoulder imbalance, four players showed trunk joint imbalance, nine players had knee joint of extension/flexion imbalance and four players showed left/right imbalance. The results showed that the number of volleyball players with differences between the strength of the bilateral knee muscles, and between the strength of the hamstrings and quadriceps muscles was higher than the number of players with differences between the strength of the shoulder internal and external rotation muscles, and higher than the number of players with differences between the strength of the lower back extension and flexion muscles. PMID:27807521

  16. Physics of volleyball: Spiking with a purpose

    NASA Astrophysics Data System (ADS)

    Behroozi, F.

    1998-05-01

    A few weeks ago our volleyball coach telephoned me with a problem: How high should a player jump to "spike" a "set" ball so it would clear the net and land at a known distance on the other side of the net?

  17. Motion analyses of adolescent rugby union players: a comparison of training and game demands.

    PubMed

    Hartwig, Timothy B; Naughton, Geraldine; Searl, John

    2011-04-01

    This research described the physiological demands of participation in adolescent rugby union including positional differences and the degree to which training practices replicate game demands. Between 2003 and 2008, 118 male adolescent rugby players aged 14 to 18 years were recruited from 10 teams representing 3 levels of adolescent rugby. Time-motion analyses using global positioning satellite tracking devices (SPI10; GPSports Systems Pty Ltd 2003) and computer-based tracking software (Trak Performance; Sports Tec Pty Ltd) applied to video footage determined player movement patterns 161 times during rugby training sessions and 53 times during rugby games. Compared with rugby training, rugby games were consistently characterized by more time spent jogging (14 vs. 8%), striding (3.2 vs. 1.3%), and sprinting (1.3 vs. 0.1%) (p < 0.001). Players also covered greater distances (4000 ± 500 vs. 2710 ± 770 m) and performed more sprints (21.8 vs. 1) during games compared with training (p < 0.001). The average sprint duration of 2 seconds was similar in games and training; however, the frequency of sprint efforts in training sessions was low (1 per hour). A major finding of this study is the disparity between physical game demands and on-field rugby training practices in adolescent players determined using time-motion analyses. Sprint pattern differences between games and training in particular could have important implications for player performance during competition. Results of this study should assist in the development of game-specific training sessions and drills that provide the kinds of physically demanding experiences observed in games. Additionally, coaches could assist in the management of adolescent players' participation loads by increasing the intensity and specificity and decreasing the volume of training.

  18. Lumbar Mechanics in Tennis Groundstrokes: Differences in Elite Adolescent Players With and Without Low Back Pain.

    PubMed

    Campbell, Amity; Straker, Leon; Whiteside, David; O'Sullivan, Peter; Elliott, Bruce; Reid, Machar

    2016-02-01

    Adolescent tennis players are at risk for low back pain (LBP). Recent research has demonstrated a potential mechanical etiology during serves; however, groundstrokes have also been suggested to load this region. Therefore, this study compared lumbar mechanics between players with and without a history of LBP during open and square stance tennis forehands and backhands. Nineteen elite, adolescent, male tennis players participated, 7 with a history of recurrent disabling LBP and 12 without. Differences in three-dimensional lumbar kinetics and kinematics were compared between pain/no pain groups and groundstrokes using linear mixed models (P < .01). There were no significant differences between pain/no pain groups. Relative to a right-handed player, groundstroke comparisons revealed that forehands had greater racquet velocity, greater lumbar right lateral flexion force, as well as upper lumbar extension/rightward rotation and lower lumbar right rotation/lateral flexion movements that were closer to or further beyond end of range than backhands. Backhands required upper lumbar leftward rotation that was beyond end range, while forehands did not. Given that players typically rotated near to their end of range during the backswing of both forehands and backhands, independent of pain, groundstrokes may contribute to the cumulative strain linked to LBP in tennis players.

  19. Reliability and Usefulness of Linear Sprint Testing in Adolescent Rugby Union and League Players.

    PubMed

    Darrall-Jones, Joshua D; Jones, Ben; Roe, Gregory; Till, Kevin

    2016-05-01

    The purpose of this study was to evaluate (a) whether there were differences in sprint times at 5, 10, 20, 30, and 40 m between rugby union and rugby league players, (b) determine the reliability and usefulness of linear sprint testing in adolescent rugby players. Data were collected on 28 rugby union and league academy players over 2 testing sessions, with 3-day rest between sessions. Rugby league players were faster at 5 m than rugby union players, with further difference unclear. Sprint time at 10, 20, 30, and 40 m was all reliable (coefficient of variation [CV] = 3.1, 1.8, 2.0, and 1.3%) but greater than the smallest worthwhile change (SWC [0.2 × between-subject SD]), rating the test as marginal for usefulness. Although the test was incapable of detecting the SWC, we recommend that practitioners and researchers use Hopkins' proposed method; whereby plotting the change score of the individual at each split (±typical error [TE] expressed as a CV) against the SWC and visually inspecting whether the TE crosses into the SWC are capable of identifying whether a change is both real (greater than the noise of the test, i.e., >TE) and of practical significance (>SWC). Researchers and practitioners can use the TE and SWC from this study to assess changes in performance of adolescent rugby players when using single beam timing gates.

  20. Strategies for Competitive Volleyball.

    ERIC Educational Resources Information Center

    Fraser, Stephen D.

    This book deals with strategies and team tactics involved in the game of volleyball. It is not intended to be an instructional book on how to execute the various skills required to play volleyball but instead endeavors to detail and explain basic tactics and strategies involved in volleyball team play. Each chapter deals with major areas of team…

  1. Trajectories of Affective States in Adolescent Hockey Players: Turning Point and Motivational Antecedents

    ERIC Educational Resources Information Center

    Gaudreau, Patrick; Amiot, Catherine E.; Vallerand, Robert J.

    2009-01-01

    This study examined longitudinal trajectories of positive and negative affective states with a sample of 265 adolescent elite hockey players followed across 3 measurement points during the 1st 11 weeks of a season. Latent class growth modeling, incorporating a time-varying covariate and a series of predictors assessed at the onset of the season,…

  2. Adolescent Identities and Sexual Behavior: An Examination of Anderson's Player Hypothesis

    ERIC Educational Resources Information Center

    Giordano, Peggy C.; Longmore, Monica A.; Manning, Wendy D.; Northcutt, Miriam J.

    2009-01-01

    We investigate the social and behavioral characteristics of male adolescents who self-identify as players, focusing particularly on Anderson's claim that this social role is inextricably linked with poverty and minority status. Results indicate that black respondents, those affiliated with liberal peers and young men who initially report a…

  3. Jumping and Landing Techniques in Elite Women’s Volleyball

    PubMed Central

    Tillman, Mark D.; Hass, Chris J.; Brunt, Denis; Bennett, Gregg R.

    2004-01-01

    Volleyball has become one of the most widely played participant sports in the world. Participation requires expertise in many physical skills and performance is often dependent on an individual’s ability to jump and land. The incidence of injury in volleyball is similar to the rates reported for sports that are considered more physical contact sports. Though the most common source of injury in volleyball is the jump landing sequence, little research exists regarding the prevalence of jumping and landing techniques. The purpose of this study was to quantify the number of jumps performed by female volleyball players in competitive matches and to determine the relative frequency of different jump-landing techniques. Videotape recordings of two matches among four volleyball teams were analyzed for this study. Each activity was categorized by jump type (offensive spike or defensive block) and phase (jump or landing). Phase was subcategorized by foot use patterns (right, left, or both). Each of the players averaged nearly 22 jump-landings per game. Foot use patterns occurred in unequal amounts (p < 0.001) with over 50% of defensive landings occurring on one foot. Coaches, physical educators, and recreation providers may utilize the findings of this inquiry to help prevent injuries in volleyball. Key Points The incidence of injury in volleyball is nearly equivalent to injury rates reported for ice hockey and soccer. Most injuries in volleyball occur during the jump landing sequence, but few data exist regarding jump landing techniques for elite female players. Our data indicate that the vast majority of jumps utilize two feet, but approximately half of landings occur with only one foot. Coaches, physical educators, and recreation providers may utilize the findings of this inquiry to prevent possible injuries in athletes, students, or those who participate in volleyball for recreational purposes. PMID:24497818

  4. Biomotor status and kinesiological education of girls aged 10 to 12 years--example: volleyball.

    PubMed

    Milić, Mirjana; Grgantov, Zoran; Katić, Ratko

    2012-09-01

    The aim of this study was to define processes of orientation and/or selection towards sports game of volleyball in schoolgirls of Kastela, aged 10-12, by examining the relations between regular classes of physical education (PE) and extracurricular sport activities. For this purpose, two morphological measures were used (body height and body mass) and a set of 11 motor tests (6 basic motor abilities tests and 5 motor achievement tests) on a sample of 242 girls aged 10-12 was used, divided into a subsample of 42 girls participating in volleyball training (Volleyball players) and a subsample of 200 girls who do not participate in volleyball training (volleyball non-players). Based on the comparison of test results of schoolgirls from Kastela and Croatian norms, factor analysis of applied variables and discriminant analysis of these variables between volleyball players and non-players, processes and/or phases of selection in forming quality volleyball players were defined. Selection processes are preceded by orientation processes in physical education classes, i.e. choosing those sport activities which are in accordance with the biomotor status of students. Results have shown that orientation and initial selection in female volleyball needs to be executed based on the motor set of psychomotor speed, repetitive strength of the trunk and flexibility (muscle tone regulation), and body height. Volleyball training has affected the muscle mass development and the development of strength factors, so that explosive strength of jumping and/or takeoff along with body height, has predominantly differentiated female volleyball players from non-players, aged 10 to 12, and serve and spike quality will have dominant influence on the match outcome.

  5. Volleyball. August 1975 - August 1977.

    ERIC Educational Resources Information Center

    Polvino, Geri, Ed.

    This guide is part of a series published by the National Association for Girls and Women in Sport. It contains 16 articles written on various aspects of volleyball, such as (1) volleyball visual aids, (2) a volleyball bibliography, (3) training for volleyball, (4) key visual cues in volleyball, (5) basic agility for beginners, and (6) solving…

  6. 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.

  7. Shoulder rotators electro-mechanical properties change with intensive volleyball practice: a pilot study.

    PubMed

    Cornu, C; Nordez, A; Bideau, B

    2009-12-01

    This pilot study was designed to assess the incidence of high-level volleyball practice on muscle strength production and muscle activation during internal and external shoulder rotations. Seven professional and seven French amateur league volleyball players performed maximal isometric at three forearm angles, concentric and eccentric isokinetic internal and external shoulder rotations. The torque production and muscle activation levels of PECTORALIS MAJOR and INFRASPINATUS were determined. Few significant differences were found for muscle activation and co-activation between amateur and professional volleyball players during both internal and external rotations. No significant difference in torque production was observed for shoulder internal rotation between professional and amateur volleyball players. Torque production was significantly higher during shoulder external rotation for amateur (46.58+/-2.62 N . m) compared to professional (35.35+/-1.17 N . m) volleyball players relative to isometric contractions, but it was not different during isokinetic efforts. The torque ratios for external/internal rotations were always significantly lower for professional (0.42+/-0.03 pooling isometric and concentric conditions) compared to amateur volleyball players (0.56+/-0.03 pooling isometric and concentric conditions). Those results emphasize that a high level of volleyball practice induces a strong external rotators deficit compared to sports such as swimming, baseball or tennis.

  8. Anthropometric profile and body composition of Irish adolescent rugby union players aged 16-18.

    PubMed

    Delahunt, Eamonn; Byrne, Risteard B; Doolin, Rachel K; McInerney, Rory G; Ruddock, Ciaran T J; Green, Brian S

    2013-12-01

    The literature suggests that one of the key determinants of success at rugby union international competitions is the anthropometric profile of players. The Irish Rugby Football Union (IRFU) long-term player development (LTPD) model is a framework designed to guide the development of the tactical, physical, and psychological domains of sporting participation. In Ireland, the Train-to-Train stage of the IRFU model is a critical stage, whereby the next developmental progression would include the transition of players into professional academies. To date, no previously published studies have examined the anthropometric profile of Irish Schools' rugby union players at the Train-to-Train stage of the IRFU model. The anthropometric profile of 136 male adolescent rugby union players at the Train-to-Train stage of the IRFU model was assessed using total-body dual-energy x-ray absorptiometry. Significant differences in height, body mass, body fat percentage, fat mass, lean mass, and fat-free mass were observed between players assigned to the forward and back units, and for specific position categorizations within each unit. Direct logistic regression revealed that body mass was a statistically significant (p < 0.01) predictor of unit position classification, with an odds ratio of 2.35, indicating that the players with a higher body mass were twice as likely to be classified as forwards. The results of this study indicate that at the Train-to-Train stage of the IRFU model, forward and back units have distinctly different anthropometric profiles. Furthermore, anthropometric differentiation also exists within specific position categorizations within each of these playing units. Thus, anthropometric profiling should be carried out on a systematic and periodic basis, because this will allow for the evaluation of the effectiveness of the implementation strategies of the IRFU model on a national basis.

  9. Lumbar facet fracture in an adolescent ice hockey player.

    PubMed

    Shaffer, W O; Taylor, M R; Sundaram, M

    1999-11-01

    A 14-year-old boy was checked hard as he was winding up to shoot in an ice hockey game. He experienced low-back pain during the game but when examined later for complaints of pain and fever, he denied trauma. Plain x-rays were normal, but a bone scan showed increased uptake at L-3. MRI evaluation revealed a lumbar mass; a CT scan showed the mass to be a hematoma and edema secondary to a facet fracture. Acute severe back pain in a hockey player should prompt a careful history and a search for musculoskeletal injury. When trauma in the lumbar spine is suspected and plain radiographs are nondiagnostic, CT scans are more precise than MRI for diagnosing injury.

  10. Frostbite in an Adolescent Football Player: A Case Report

    PubMed Central

    Rivlin, Michael; King, Marnie; Kruse, Richard; Ilyas, Asif M.

    2014-01-01

    Objective: To present the case of vascular compromise of a finger from a confluent circumferential blister due to an inappropriately applied commercial cold pack in a high school athlete and to describe the mechanism of iatrogenic injury, acute surgical management, rehabilitation, and pathophysiology of frostbite and constriction injuries. Background: A 17-year-old male football player presented with a frostbite and constriction injury to the index finger secondary to prolonged use of a cooling pack after a mild traumatic injury to the digit. He developed a prolonged sensory deficit from thermal injury, as well as acute vascular compromise requiring urgent operative intervention. Differential Diagnosis: Frostbite and constriction injury to the index finger. Treatment: Emergency surgical decompression and occupational therapy. Uniqueness: Frostbite injuries can occur iatrogenically because of inappropriate use of cooling devices or gel packs. Fingers are commonly injured extremities that are particularly susceptible to frostbite and compression injuries. To our knowledge, no case of vascular compromise from the blister constriction of digits has been reported. Conclusions: Patients and their caregivers must be educated about how to properly use cooling devices. Clinicians need to fully evaluate patients with iatrogenic frostbite injuries, giving particular attention to neurovascular status, and must recognize the need for surgical release of constriction syndrome to prevent substantial morbidity. PMID:24143903

  11. Football injuries in children and adolescent players: are there clues for prevention?

    PubMed

    Faude, Oliver; Rößler, Roland; Junge, Astrid

    2013-09-01

    Football (soccer) is the world's most popular sport with most players being younger than 18 years. Playing football can induce beneficial health effects, but there is also a high risk of injury. Therefore, it is necessary to implement measures for preventing injuries. The present review analyzes and summarizes published scientific information on the incidence and characteristics of football injuries in children and adolescent players to arrive at sound conclusions and valid considerations for the development of injury-prevention programs. A literature search was conducted up to November 2012. Fifty-three relevant scientific publications were detected. Thirty-two studies fulfilled the inclusion criteria for pooled analysis. Additional information from the remaining 21 studies was considered where appropriate to obtain a broader perspective on the injury problem in children and youth football. Training injury incidence was nearly constant for players aged 13-19 years, ranging from 1 to 5 injuries per 1,000 h training. Match injury incidence tended to increase with age through all age groups, with an average incidence of about 15 to 20 injuries per 1,000 match hours in players older than 15 years. Between 60 and 90 % of all football injuries were classified as traumatic and about 10-40 % were overuse injuries. Most injuries (60-90 %) were located at the lower extremities with the ankle, knee, and thigh being mostly affected. The frequency of upper-extremity and head/face injuries was higher in those studies that analyzed match injuries only. The most common injury types were strains, sprains, and contusions (10 up to 40 % each). There is some evidence that the risk of traumatic injuries and, in particular, of sustaining a fracture, contusion, or concussion was higher during match play than in practice sessions. Fractures were more frequent in children younger than 15 years than in older players. About half of all time-loss injuries led to an absence from sport of less

  12. The effect of plyometric training on power and kicking distance in female adolescent soccer players.

    PubMed

    Rubley, Mack D; Haase, Amaris C; Holcomb, William R; Girouard, Tedd J; Tandy, Richard D

    2011-01-01

    The purpose of this study was to measure the effects of low-frequency, low-impact plyometric training on vertical jump (VJ) and kicking distance in female adolescent soccer players. Sixteen adolescent soccer players were studied (age 13.4 ± 0.5 years) across 14 weeks. The control group (general soccer training only) had 6 subjects, and the plyometric training (general soccer training plus plyometric exercise) group had 10 subjects. All subjects were tested for VJ and kicking distance on 3 occasions: pre-test, 7 weeks, and 14 weeks. Data were analyzed using a 2 (Training) × 3 (Test) analysis of variance (ANOVA) with repeated measures on the factor test. No significant difference in kicking distance was found between groups at pre-test (p = 0.688) or 7 weeks (p = 0.117). The plyometric group had significantly greater kicking distance after 14 weeks (p < 0.001). No significant difference in VJ height was found between groups at pre-test (p = 0.837) or 7 weeks (p = 0.108). The plyometric group had a significantly higher VJ after 14 weeks (p = 0.014). These results provide strength coaches with a safe and effective alternative to high-intensity plyometric training. Based on these findings, to increase lower-body power resulting in increased VJ and kicking distance, strength coaches should implement once-weekly, low-impact plyometric training programs with their adolescent athletes.

  13. Vitamin D receptor gene FokI polymorphisms influence bone mass in adolescent football (soccer) players.

    PubMed

    Diogenes, Maria Eduarda L; Bezerra, Flávia Fioruci; Cabello, Giselda M K; Cabello, Pedro H; Mendonça, Laura M C; Oliveira Júnior, Astrogildo V; Donangelo, Carmen M

    2010-01-01

    The genetic influence on bone mineralization during adolescence is unclear possibly due to modifying factors such as skeletal maturation and lifestyle. We evaluated the influence of polymorphisms of the vitamin D receptor (VDR) gene on longitudinal changes in bone mass, bone- and calcium-related hormones in 46 adolescent soccer players (11.8-14.2 years). Total body bone mineral content (TBMC) and density (TBMD) were measured at baseline and after 6 months. Insulin-like growth factor-I (IGF-1), testosterone, intact parathyroid hormone, and activity of plasma bone alkaline phosphatase were measured at baseline and after 3 months. The influence of FokI or TaqI VDR genotypes on changes in the outcome variables were analyzed by univariate ANOVA with adjustment for chronological age, skeletal age and body weight at baseline. At baseline, boys with Ff genotype had higher TBMC, TBMD, TBMD Z-score compared to those with FF genotype (P < 0.05). After 3 months, Ff boys also had higher increment in plasma IGF-1 (P < 0.05). FokI polymorphism did not influence changes in bone mass measurements after 6 months, although differences detected at baseline remained significant after 6 months. There were no differences in the outcome variables according to TaqI genotypes. This study demonstrates that FokI polymorphisms affect bone mass in Brazilian adolescent soccer players and suggests that the FokI effect on bone mineralization occurs during bone maturation, possibly at the initial pubertal stages.

  14. A one season prospective cohort study of volleyball injuries

    PubMed Central

    Verhagen, E; Van der Beek, A J; Bouter, L; Bahr, R; Mechelen, W

    2004-01-01

    Objective: To estimate the overall incidence of acute and overuse volleyball injuries, and to describe factors associated with ankle sprains. Methods: 486 players from the second and third Dutch national volleyball divisions participated in the study and were followed prospectively during a whole season. Three measurements were made during the season (baseline, follow up 1, and follow up 2), where all players completed a questionnaire on demographic variables (only at baseline), sports participation, use of preventive measures, and previous injuries. Volleyball exposure during training and matches was recorded for each individual player by the coach on a weekly exposure form. In case of injury the coach provided the injured player with an injury registration form, which had to be completed within one week after the onset of injury. Results: 100 injuries were reported, resulting in an overall injury incidence of 2.6 injuries/1000 hours. The incidence of acute injuries was 2.0/1000 hours. Ankle sprains (n = 41) accounted for most of the acute injuries, and 31 (75%) of all players with an ankle sprain reported a previous ankle sprain. Twenty five overuse injuries were reported. The overall incidence of overuse injuries was 0.6/1000 hours; the back and the shoulder were the most common sites. Conclusions: Ankle sprain is the most common injury in volleyball, accounting for 41% of all volleyball related injuries. Previous injury seems to be an important risk factor for an ankle sprain. Injury prevention programmes should focus on ankle sprains and concentrate on players with previous ankle sprains. PMID:15273190

  15. 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

  16. Predicting Volleyball Serve-Reception.

    PubMed

    Paulo, Ana; Zaal, Frank T J M; Fonseca, Sofia; Araújo, Duarte

    2016-01-01

    Serve and serve-reception performance have predicted success in volleyball. Given the impact of serve-reception on the game, we aimed at understanding what it is in the serve and receiver's actions that determines the selection of the type of pass used in serve-reception and its efficacy. Four high-level volleyball players received jump-float serves from four servers in two reception zones-zone 1 and 5. The ball and the receiver's head were tracked with two video cameras, allowing 3D world-coordinates reconstruction. Logistic-regression models were used to predict the type of pass used (overhand or underhand) and serve-reception efficacy (error, out, or effective) from variables related with the serve kinematics and related with the receiver's on-court positioning and movement. Receivers' initial position was different when in zone 1 and 5. This influenced the serve-related variables as well as the type of pass used. Strong predictors of using an underhand rather than overhand pass were higher ball contact of the server, reception in zone 1, receiver's initial position more to the back of the court and backward receiver movement. Receiver's larger longitudinal displacements and an initial position more to the back of the court had a strong relationship with the decreasing of the serve-reception efficacy. Receivers' positioning and movement were the factors with the largest impact on the type of pass used and the efficacy of the reception. Reception zone affected the variance in the ball's kinematics (with the exception of the ball's lateral displacement), as well as in the receivers' positioning (distances from the net and from the target). Also the reception zone was associated with the type of pass used by the receiver but not with reception efficacy. Given volleyball's rotation rule, the receiver needs to master receiving in the different reception zones; he/she needs to adapt to the diverse constraints of each zone to maintain performance efficacy. Thus, being

  17. Predicting Volleyball Serve-Reception

    PubMed Central

    Paulo, Ana; Zaal, Frank T. J. M.; Fonseca, Sofia; Araújo, Duarte

    2016-01-01

    Serve and serve-reception performance have predicted success in volleyball. Given the impact of serve-reception on the game, we aimed at understanding what it is in the serve and receiver's actions that determines the selection of the type of pass used in serve-reception and its efficacy. Four high-level volleyball players received jump-float serves from four servers in two reception zones—zone 1 and 5. The ball and the receiver's head were tracked with two video cameras, allowing 3D world-coordinates reconstruction. Logistic-regression models were used to predict the type of pass used (overhand or underhand) and serve-reception efficacy (error, out, or effective) from variables related with the serve kinematics and related with the receiver's on-court positioning and movement. Receivers' initial position was different when in zone 1 and 5. This influenced the serve-related variables as well as the type of pass used. Strong predictors of using an underhand rather than overhand pass were higher ball contact of the server, reception in zone 1, receiver's initial position more to the back of the court and backward receiver movement. Receiver's larger longitudinal displacements and an initial position more to the back of the court had a strong relationship with the decreasing of the serve-reception efficacy. Receivers' positioning and movement were the factors with the largest impact on the type of pass used and the efficacy of the reception. Reception zone affected the variance in the ball's kinematics (with the exception of the ball's lateral displacement), as well as in the receivers' positioning (distances from the net and from the target). Also the reception zone was associated with the type of pass used by the receiver but not with reception efficacy. Given volleyball's rotation rule, the receiver needs to master receiving in the different reception zones; he/she needs to adapt to the diverse constraints of each zone to maintain performance efficacy. Thus

  18. Incidence, aetiology and prevention of musculoskeletal injuries in volleyball: A systematic review of the literature.

    PubMed

    Kilic, O; Maas, M; Verhagen, E; Zwerver, J; Gouttebarge, V

    2017-04-09

    Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures of volleyball injuries. To this end, a highly sensitive search strategy was built based on two groups of keywords (and their synonyms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost. The results showed that ankle, knee and shoulder injuries are the most common injuries sustained while playing volleyball. Results are presented separately for acute and overuse injuries, as well as for contact and non-contact injuries. Measures to prevent musculoskeletal injuries, anterior knee injuries and ankle injuries were identified in the scientific literature. These preventive measures were found to have a significant effect on decreasing the occurrence of volleyball injuries (for instance on ankle injuries with a reduction from 0.9 to 0.5 injuries per 1000 player hours). Our systematic review showed that musculoskeletal injuries are common among volleyball players, while effective preventive measures remain scarce. Further epidemiological studies should focus on other specific injuries besides knee and ankle injuries, and should also report their prevalence and not only the incidence. Additionally, high-quality studies on the aetiology and prevention of shoulder injuries are lacking and should be a focus of future studies.

  19. Volleyball Scoring Systems.

    ERIC Educational Resources Information Center

    Calhoun, William; Dargahi-Noubary, G. R.; Shi, Yixun

    2002-01-01

    The widespread interest in sports in our culture provides an excellent opportunity to catch students' attention in mathematics and statistics classes. One mathematically interesting aspect of volleyball, which can be used to motivate students, is the scoring system. (MM)

  20. Ethnicity-related variations of left ventricular remodeling in adolescent amateur football players.

    PubMed

    Pelà, G; Li Calzi, M; Crocamo, A; Pattoneri, P; Goldoni, M; Anedda, A; Musiari, L; Biggi, A; Bonetti, A; Montanari, A

    2015-06-01

    Adult and adolescent elite black athletes display - as compared with their white counterparts - excessively increased left ventricle (LV) wall thickness (LVWT), mass (LVM), and relative wall thickness (RWT). To investigate such ethnicity-related differences in non-professional adolescent athletes, 138 male, amateur football players [age 14.0 ± 1.7 years, 42 West-African blacks (BA) and 96 Italian whites (WA)] underwent an echocardiographic study of LV diameters, LVWT, maximal wall thickness (MWT), LVM, and RWT as remodeling index. BA vs WA exhibited greater thickness of septum and posterior wall, higher MWT (10.3 ± 1.7 vs 8.8 ± 1.1 mm), and higher LVM (117 ± 27 vs 101 ± 20 g/m(2)) and RWT (0.44 ± 0.07 vs 0.35 ± 0.04). Age, systolic blood pressure, body mass index, and ethnicity predicted MWT and LVM, whereas ethnicity was the sole strong predictor of RWT. The greater MWT, LVWT, and LVM of 14-year-old, amateur-level BA vs WA indicates that ethnicity substantially affects LV structure in adolescent, non-professional athletes. In contrast with MWT and LVM, elevated RWT was predicted by black ethnicity only. We suggest that concentric-type LV remodeling is a peculiar LV phenotype in adolescent African athletes.

  1. Body composition and physical capacity of elite adolescent female tennis players.

    PubMed

    Ziemann, Ewa; Sledziewska, Ewelina; Grzywacz, Tomasz; Gibson, Ann L; Wierzba, Tomasz H

    2011-01-01

    The study was performed to evaluate relationships among the major anthropological parameters: (body mass - BM, height, body mass index - BMI, lean body mass - FFM, proportion of fat mass -Fat%), physical capacity, and the tennis federations ranking position as an index of the temporal sport success. Seventeen elite female tennis players, divided into three age-matched groups (15, 16, and 17 yr) participated in this study. All the players had a national singles ranking (positions between 1st-80th) and in International Tennis Federation's Junior Circuit ranking (ITFJC; 21st to 990th position of ITF). Body composition was assessed via bioelectrical impedance. Maximal aerobic capacity (VO2max) was calculated from the distance covered in 12-min run test via Cooper's formula. Wingate test with lactate assay was used as an index of anaerobic capacity. There was a significant age-related trend for an increase in BM, height, FFT, and Fat%, associated with impressive shift of the anthropological indexes of body weight and height, assessed by the percentile chart analysis. The unexpected body growth spurt evidently observed between aged 15 and 17 is supposed to reflect a delay in somatic development, related to extensive exercise load. Body composition did not correlate to the ranking positions. All tested tennis players revealed excellent aerobic capacity associated with poor indices of anaerobic fitness. The position in the tennis federations rankings correlated to VO2max but not with maximal power or maximal work output assessed by Wingate test. In the whole group the maximal power and work output were proportional to BMI and FFM, but not to Fat%. In conclusion, in light of the contradictory reports concerning a possible link between strenuous regular exercise performed by young children and adolescent elite sportsmen our data indicate a delayed growth spurt in the elite female tennis players to occur between ages 15 and 17. The other important finding in terms of

  2. Validity and usefulness of the Line Drill test for adolescent basketball players: a Bayesian multilevel analysis.

    PubMed

    Carvalho, Humberto M; Gonçalves, Carlos E; Grosgeorge, Bernard; Paes, Roberto R

    2017-04-10

    The study examined the validity of the Line Drill test (LD) in male adolescent basketball players (10-15 years). Sensitiveness of the LD to changes in performance across a training and competition season (4 months) was also considered. Age, maturation, body size and LD were measured (n = 57). Sensitiveness of the LD was examined pre- and post-competitive season in a sub-sample (n = 44). The time at each of the four shuttle sprints of the LD (i.e. four stages) was modelled with Bayesian multilevel models. We observed very large correlation of performance at stage 4 (full LD protocol) with stage 3, but lower correlations with the early LD stages. Players' performance by somatic maturity differed substantially only when considering full LD protocol performance. Substantial improvements in all stages of the protocol were observed across the 4-month competitive season. The LD protocol should be shortened by the last full court shuttle sprint, remaining sensitive to training exposure, and independent of maturity status and body size.

  3. A rare cause of chronic elbow pain in an adolescent baseball player: a case report

    PubMed Central

    Wasylynko, David

    2016-01-01

    Objective: To present a case of chronic elbow pain as a result of a hidden underlying osteochondral defect. Clinical Features: A 17-year old baseball player presented with chronic lateral elbow pain. Examination revealed swelling of the elbow with signs of possible ligament, muscle, and tendon injury. Diagnosis and Treatment: Although there was apparent soft-tissue injury, the elbow swelling created immediate suspicion of a more serious underlying condition. Examination revealed a swollen and tender elbow, with plain x-ray confirming a subchondral bone disorder (osteochondral defect) of the capitellum. Surgical repair was performed by an orthopedic surgeon using DeNovo NT Natural Tissue Grafts: the implantation of small pieces of juvenile joint cartilage into the affected area, using glue-like fibrin. Rehabilitation of the elbow began immediately following surgery. Summary: Examination and imaging indicated that elbow pain in an adolescent baseball player could be from multiple sources, however, the chronic swelling raised suspicion of a condition requiring immediate and further investigation. PMID:27713578

  4. THE RELATIONSHIP BETWEEN TRUNK ENDURANCE PLANK TESTS AND ATHLETIC PERFORMANCE TESTS IN ADOLESCENT SOCCER PLAYERS

    PubMed Central

    Kaneoka, Koji

    2016-01-01

    Background Although it is believed that trunk function is important for athletic performance, few researchers have demonstrated a significant relationship between the trunk function and athletic performance. Recently, the prone plank and side plank tests have been used to assess trunk function. Purpose The purpose of this study was to investigate the relationships between trunk endurance plank tests and athletic performance tests, including whether there is a relationship between long distance running and trunk endurance plank tests in adolescent male soccer players. Study design Cross sectional study design. Methods Fifty-five adolescent male soccer players performed prone and side plank tests and seven performance tests: the Cooper test, the Yo-Yo intermittent recovery test, the step 50 agility test, a 30-m sprint test, a vertical countermovement jump, a standing five-step jump, and a rebound jump. The relationships between each individual plank test, the combined score of both plank tests, and performance tests were analyzed using the Pearson correlation coefficient. Results The combined score of plank tests was highly correlated with the Yo-Yo intermittent recovery test (r = 0.710, p < 0.001), and was moderately correlated with the Cooper test (r = 0.567, p < 0.001). Poor correlation was observed between the prone plank test and step 50 agility test (r = -0.436, p = 0.001) and no significant correlations were observed between plank tests and jump performance tests. Conclusions The results suggest that trunk endurance plank tests are positively correlated with the Yo-Yo intermittent recovery test, the Cooper test, and the step 50 agility test. Level of Evidence Level 2 PMID:27757284

  5. Experiences of returning to elite beach volleyball after shoulder injury

    PubMed Central

    Bele, Sofie; Östenberg, Anna Hafsteinsson; Sjöström, Rita; Alricsson, Marie

    2015-01-01

    The purpose of this study was to examine beach volleyball players’ experience regarding shoulder injury and how it affects their return to play. To achieve the research aims a qualitative design with semi-structured interviews had been conducted, five elite beach volleyball players, four men and one woman aged 27–42 participated in the study. All participants had suffered a severe shoulder injury, with absence from training and competing for at least 28 days. The findings of this study indicate that it is the individual’s inner motivation, together with a clear goal and support from the community, family, teammate and coach that are the most important factors when going through rehabilitation and getting back to playing beach volleyball after a shoulder injury. All participants had been affected by their injury in some way; some of the participants had been affected in a positive way since they had become mentally stronger and had developed better volleyball technique after rehabilitation. The conclusions of this study indicate that there are three distinct factors that increase the chances of getting back to playing beach volleyball after shoulder injury; it is the players’ self motivation, together with a clear goal and support from the community. PMID:26331135

  6. Agreement between Two Methods of Dietary Data Collection in Male Adolescent Academy-Level Soccer Players

    PubMed Central

    Briggs, Marc A.; Rumbold, Penny L. S.; Cockburn, Emma; Russell, Mark; Stevenson, Emma J.

    2015-01-01

    Collecting accurate and reliable nutritional data from adolescent populations is challenging, with current methods providing significant under-reporting. Therefore, the aim of the study was to determine the accuracy of a combined dietary data collection method (self-reported weighed food diary, supplemented with a 24-h recall) when compared to researcher observed energy intake in male adolescent soccer players. Twelve Academy players from an English Football League club participated in the study. Players attended a 12 h period in the laboratory (08:00 h–20:00 h), during which food and drink items were available and were consumed ad libitum. Food was also provided to consume at home between 20:00 h and 08:00 h the following morning under free-living conditions. To calculate the participant reported energy intake, food and drink items were weighed and recorded in a food diary by each participant, which was supplemented with information provided through a 24-h recall interview the following morning. Linear regression, limits of agreement (LOA) and typical error (coefficient of variation; CV) were used to quantify agreement between observer and participant reported 24-h energy intake. Difference between methods was assessed using a paired samples t-test. Participants systematically under-reported energy intake in comparison to that observed (p < 0.01) but the magnitude of this bias was small and consistent (mean bias = −88 kcal·day−1, 95% CI for bias = −146 to −29 kcal·day−1). For random error, the 95% LOA between methods ranged between −1.11 to 0.37 MJ·day−1 (−256 to 88 kcal·day−1). The standard error of the estimate was low, with a typical error between measurements of 3.1%. These data suggest that the combined dietary data collection method could be used interchangeably with the gold standard observed food intake technique in the population studied providing that appropriate adjustment is made for the systematic under-reporting common to such

  7. 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

  8. Pseudonephritis is associated with high urinary osmolality and high specific gravity in adolescent soccer players.

    PubMed

    Van Biervliet, Stephanie; Van Biervliet, Jean Pierre; Watteyne, Karel; Langlois, Michel; Bernard, Dirk; Vande Walle, Johan

    2013-08-01

    The study aimed to evaluate the effect of exercise on urine sediment in adolescent soccer players. In 25 15-year-old (range 14.4-15.8 yrs) athletes, urinary protein, osmolality and cytology were analyzed by flow cytometry and automated dipstick analysis before (T(0)), during (T(1)), and after a match (T(2)). All athletes had normal urine analysis and blood pressure at rest, tested before the start of the soccer season. Fifty-eight samples were collected (T(0): 20, T(1): 17, T(2): 21). Proteinuria was present in 20 of 38 samples collected after exercise. Proteinuria was associated with increased urinary osmolality (p < .001) and specific gravity (p < .001). Hyaline and granular casts were present in respectively 8 of 38 and 8 of 38 of the urinary samples after exercise. The presence of casts was associated with urine protein concentration, osmolality, and specific gravity. This was also the case for hematuria (25 of 38) and leucocyturia (9 of 38). Squamous epithelial cells were excreted in equal amounts to white and red blood cells. A notable proportion of adolescent athletes developed sediment abnormalities, which were associated with urinary osmolality and specific gravity.

  9. Effectiveness of the call in beach volleyball attacking play.

    PubMed

    Künzell, Stefan; Schweikart, Florian; Köhn, Daniel; Schläppi-Lienhard, Olivia

    2014-12-09

    In beach volleyball the setter has the opportunity to give her or his hitter a "call". The call intends that the setter suggests to her or his partner where to place the attack in the opponent's court. The effectiveness of a call is still unknown. We investigated the women's and men's Swiss National Beach Volleyball Championships in 2011 and analyzed 2185 attacks. We found large differences between female and male players. While men called in only 38.4% of attacks, women used calls in 85.5% of attacks. If the male players followed a given call, 63% of the attacks were successful. The success rate of attacks without any call was 55.8% and 47.6% when the call was ignored. These differences were not significant (χ(2)(2) = 4.55, p = 0.103). In women's beach volleyball, the rate of successful attacks was 61.5% when a call was followed, 35% for attacks without a call, and 42.6% when a call was ignored. The differences were highly significant (χ(2)(2) = 23.42, p < 0.0005). Taking into account the findings of the present study, we suggested that the call was effective in women's beach volleyball, while its effect in men's game was unclear. Considering the quality of calls we indicate that there is a significant potential to increase the effectiveness of a call.

  10. Effectiveness of the Call in Beach Volleyball Attacking Play

    PubMed Central

    Künzell, Stefan; Schweikart, Florian; Köhn, Daniel; Schläppi-Lienhard, Olivia

    2014-01-01

    In beach volleyball the setter has the opportunity to give her or his hitter a “call”. The call intends that the setter suggests to her or his partner where to place the attack in the opponent’s court. The effectiveness of a call is still unknown. We investigated the women’s and men’s Swiss National Beach Volleyball Championships in 2011 and analyzed 2185 attacks. We found large differences between female and male players. While men called in only 38.4% of attacks, women used calls in 85.5% of attacks. If the male players followed a given call, 63% of the attacks were successful. The success rate of attacks without any call was 55.8% and 47.6% when the call was ignored. These differences were not significant (χ2(2) = 4.55, p = 0.103). In women’s beach volleyball, the rate of successful attacks was 61.5% when a call was followed, 35% for attacks without a call, and 42.6% when a call was ignored. The differences were highly significant (χ2(2) = 23.42, p < 0.0005). Taking into account the findings of the present study, we suggested that the call was effective in women’s beach volleyball, while its effect in men’s game was unclear. Considering the quality of calls we indicate that there is a significant potential to increase the effectiveness of a call. PMID:25713679

  11. "Yes, we can!": Perceptions of collective efficacy sources in volleyball.

    PubMed

    Fransen, Katrien; Vanbeselaere, Norbert; Exadaktylos, Vasileios; Vande Broek, Gert; De Cuyper, Bert; Berckmans, Daniel; Ceux, Tanja; De Backer, Maarten; Boen, Filip

    2012-01-01

    Collective efficacy can be defined as a group's shared confidence that they will successfully achieve their goal. We examined which behaviours and events are perceived as sources of collective efficacy beliefs in a volleyball context. In study 1, volleyball coaches from the highest volleyball leagues (n = 33) in Belgium indicated the most important sources of collective efficacy. This list was then adapted based on the literature and on feedback given by an expert focus group, resulting in a 40-item questionnaire. In Study 2, coaches and players from all levels of volleyball in Belgium (n = 2365) rated each of these sources on their predictive value for collective efficacy. A principal component analysis revealed that the 40 sources could be divided into eight internally consistent factors. Positive supportive communication (e.g., enthusiasm after making a point) was identified as the factor most predictive for positive collective efficacy beliefs. The factor referring to the negative emotional reactions of players (e.g., discouraging body language) was the most predictive for negative collective efficacy beliefs. These findings offer a starting point for the design of continuous measurements of collective efficacy through observation.

  12. 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

  13. Validity of the jump-and-reach test in sub-elite adolescent handball players.

    PubMed

    Muehlbauer, Thomas; Pabst, Jan; Granacher, Urs; Büsch, Dirk

    2016-08-18

    The primary purpose of this study was to examine concurrent validity of the jump-and-reach (JaR) test using the Vertec system and a criterion device (i.e., Optojump system). In separate sub-analyses, we investigated the influence of gym floor condition and athletes' sex on the validity of vertical jump height. Four hundred and forty sub-elite adolescent female (n = 222, mean age: 14 ± 1 years, age range: 13-15 years) and male (n = 218, mean age: 15 ± 1 years, age range: 14-16 years) handball players performed the JaR test in gyms with region or point elastic floors. Maximal vertical jump height was simultaneously assessed using the Vertec and the Optojump system. In general, significantly higher jump heights were obtained for the Vertec compared to the Optojump system (11.2 cm, [INCREMENT]31%, Cohen´s d = 2.58). The sub-analyses revealed significantly larger jump heights for the Vertec compared to the Optojump system irrespective of gym floor condition and players' sex. The association between Optojump and Vertec-derived vertical jump height amounted to rP = 0.84, with a coefficient of determination (R) of 0.71. The sub-analyses indicated significantly larger correlations in males (rP = 0.75, R = 0.56) than in females (rP = 0.63, R = 0.40). Yet, correlations were not significantly different between region (rP = 0.83, R = 0.69) as opposed to point elastic floor (rP = 0.87, R = 0.76). Our findings indicate that the two apparatus cannot be used interchangeably. Consequently, gym floor and sex specific regression equations were provided to estimate true (Optojump system) vertical jump height from Vertec-derived data.

  14. 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.

  15. Shoulder proprioception is not related to throwing speed or accuracy in elite adolescent male baseball players.

    PubMed

    Freeston, Jonathan; Adams, Roger D; Rooney, Kieron

    2015-01-01

    Understanding factors that influence throwing speed and accuracy is critical to performance in baseball. Shoulder proprioception has been implicated in the injury risk of throwing athletes, but no such link has been established with performance outcomes. The purpose of this study was to describe any relationship between shoulder proprioception acuity and throwing speed or accuracy. Twenty healthy elite adolescent male baseball players (age, 19.6 ± 2.6 years), who had represented the state of New South Wales in the past 18 months, were assessed for bilateral active shoulder proprioception (shoulder rotation in 90° of arm abduction moving toward external rotation using the active movement extent discrimination apparatus), maximal throwing speed (MTS, meters per second measured via a radar gun), and accuracy (total error in centimeters determined by video analysis) at 80 and 100% of MTS. Although proprioception in the dominant and nondominant arms was significantly correlated with each other (r = 0.54, p < 0.01), no relationship was found between shoulder proprioception and performance. Shoulder proprioception was not a significant determinant of throwing performance such that high levels of speed and accuracy were achieved without a high degree of proprioception. There is no evidence to suggest therefore that this particular method of shoulder proprioception measurement should be implemented in clinical practice. Consequently, clinicians are encouraged to consider proprioception throughout the entire kinetic chain rather than the shoulder joint in isolation as a determining factor of performance in throwing athletes.

  16. Asymptomatic Elite Adolescent Tennis Players' Signs of Tendinosis in Their Dominant Shoulder Compared With Their Nondominant Shoulder

    PubMed Central

    Johansson, Fredrik R.; Skillgate, Eva; Adolfsson, Anders; Jenner, Göran; DeBri, Edin; Swärdh, Leif; Cools, Ann M.

    2015-01-01

    Context Tennis is an asymmetric overhead sport with specific muscle-activation patterns, especially eccentrically in the rotator cuff. Magnetic resonance imaging (MRI) findings in asymptomatic adolescent elite tennis players have not previously been reported. Objective The first aim of the study was to describe MRI findings regarding adaptations or abnormalities, as well as muscle cross-sectional area (CSA), of the rotator cuff. The second aim of the study was to investigate the rotator cuff based on the interpretation of the MRI scans as normal versus abnormal, with the subdivision based on the grade of tendinosis, and its association with eccentric rotator cuff strength in the dominant arm (DA) of the asymptomatic elite adolescent tennis player. Setting Testing environment at the radiology department of Medicinsk Röntgen AB. Patients or Other Participants Thirty-five asymptomatic elite tennis players (age = 17.4 ± 2.7 years) were selected based on ranking and exposure time. Intervention(s) We assessed MRI scans and measured the CSA of the rotator cuff muscle. The non-DA (NDA) was used as a control. In addition, eccentric testing of the external rotators of the DA was performed with a handheld dynamometer. Results The DA and NDA displayed different frequencies of infraspinatus tendinosis (grade 1 changes) (P < .05). Rotator cuff measurements revealed larger infraspinatus and teres minor CSA (P < .05) in the DA than in the NDA. Mean eccentric external-rotation strength in the DA stratified by normal tendon and tendinosis was not different between groups (P = .723). Conclusions Asymptomatic adolescent elite tennis players demonstrated infraspinatus tendinosis more frequently in the DA than in the NDA. Clinicians must recognize these tendon changes in order to modify conditioning and performance programs appropriately. PMID:26651279

  17. Anthropometric and Physical Fitness Differences Among Brazilian Adolescents who Practise Different Team Court Sports

    PubMed Central

    Silva, Diego Augusto Santos; Petroski, Edio Luiz; Gaya, Adroaldo Cesar Araujo

    2013-01-01

    The objective of this work was to compare the anthropometric and physical fitness characteristics of Brazilian adolescents who practise team court sports and to compare specific parameters obtained for adolescents with data from the general population. This was a cross-sectional study of 1,348 male adolescents grouped as follows: basketball players (n = 287), indoor soccer players (n = 665), handball players (n = 108) and volleyball players (n = 288), all between 10 and 14 years of age. Anthropometric (body mass, body height, arm span, and body mass index) and physical fitness data (flexibility, muscular strength, explosive power, speed, aerobic fitness and agility) were collected. The Brazilian population was used as a reference and compared to the adolescent subjects using Z scores for all variables. Anthropometric characteristics and performances in physical fitness tests differed (p<0.05) among players of different sports. In addition, for each variable assessed, adolescents who practised team court sports showed similar or improved results compared to their counterparts in the general population (p<0.05). Furthermore, the anthropometric and physical fitness characteristics differed depending on the team court sport practised. These findings may elucidate which physical abilities are most impacted by the practise of a particular team sport as well as help teachers and physical education and sport professionals identify talented adolescents. PMID:23717357

  18. The effect of deprivation on the developmental activities of adolescent rugby union players in Wales.

    PubMed

    Winn, Charles O N; Ford, Paul R; McNarry, Melitta A; Lewis, Jason; Stratton, Gareth

    2016-12-26

    The developmental activities of rugby union players and their interaction with deprivation remain to be elucidated. Five-hundred and ninety elite junior rugby union players (14.8 ± 0.5 years) were split into deprivation quintiles. These players subsequently completed a participant history questionnaire to record their involvement in rugby and other sports. Players accumulated 1987 ± 1297 h in rugby between 6 and 15 years of age. During the mini rugby stage (6-10 years of age), players accumulated an average of 113 ± 105, 89 ± 69 and 43 ± 19 h per year in rugby play, practice and competition, respectively. Moreover, 461 players engaged in an average of two other sports during the mini rugby stage. During the junior rugby stage (11-15 years of age), players accumulated 179 ± 98, 115 ± 90 and 64 ± 26 h per year in rugby practice, play and competition, respectively, and 538 players took part in three other sports. Players who were more deprived accumulated less rugby hours and participated in fewer other sports, but age milestones were not different between deprivation quintiles. There were no differences within developmental activities in rugby between deprivation groups.

  19. Vertical jumping tests in volleyball: reliability, validity, and playing-position specifics.

    PubMed

    Sattler, Tine; Sekulic, Damir; Hadzic, Vedran; Uljevic, Ognjen; Dervisevic, Edvin

    2012-06-01

    Vertical jumping is known to be important in volleyball, and jumping performance tests are frequently studied for their reliability and validity. However, most studies concerning jumping in volleyball have dealt with standard rather than sport-specific jumping procedures and tests. The aims of this study, therefore, were (a) to determine the reliability and factorial validity of 2 volleyball-specific jumping tests, the block jump (BJ) test and the attack jump (AJ) test, relative to 2 frequently used and systematically validated jumping tests, the countermovement jump test and the squat jump test and (b) to establish volleyball position-specific differences in the jumping tests and simple anthropometric indices (body height [BH], body weight, and body mass index [BMI]). The BJ was performed from a defensive volleyball position, with the hands positioned in front of the chest. During an AJ, the players used a 2- to 3-step approach and performed a drop jump with an arm swing followed by a quick vertical jump. A total of 95 high-level volleyball players (all men) participated in this study. The reliability of the jumping tests ranged from 0.97 to 0.99 for Cronbach's alpha coefficients, from 0.93 to 0.97 for interitem correlation coefficients and from 2.1 to 2.8 for coefficients of variation. The highest reliability was found for the specific jumping tests. The factor analysis extracted one significant component, and all of the tests were highly intercorrelated. The analysis of variance with post hoc analysis showed significant differences between 5 playing positions in some of the jumping tests. In general, receivers had a greater jumping capacity, followed by libero players. The differences in jumping capacities should be emphasized vis-a-vis differences in the anthropometric measures of players, where middle hitters had higher BH and body weight, followed by opposite hitters and receivers, with no differences in the BMI between positions.

  20. The effects of sole vibration stimulation on Korean male professional volleyball players’ jumping and balance ability

    PubMed Central

    Kim, Yong-Youn; Min, Kyoung-Ok; Choi, Jung-Hyun; Kim, Soon-Hee

    2016-01-01

    [Purpose] The purpose of this study was to investigate differences in jumping ability and lower limb balance ability elicited by plyometric training and vibration exercise, of volleyball players with and without ankle injuries, which frequently occur among Korean professional volleyball players. [Subjects and Methods] Twenty-eight volleyball players were divided into the following groups: plyometric with ankle injury (PAI) group; plyometric with non-ankle injury (PAN) group; vibrator with ankle injury (VAI) group; and vibrator with non-ankle injury (VAN) group. After exercise and whole body vibration stimulation, their vertical jumping abilities, side step, and static equilibrium ability were measured. [Results] The vibration exercise group which had experienced ankle injuries showed significant improvements in the sidestep test after the intervention compared to before the intervention. In vertical jumping as well, significant improvements were observed in the VAI group and the VAN group following vibration exercise. In the balance ability test, significant improvesments in the PAN group and the PAI group were observed after the intervention. According to the results of the right side, there was significant change in the left/back side test and the right/back side test before and after the intervention; and in the test of one-leg standing with eyes closed, there were significant group, timing, and interaction effects. [Conclusions] The training method which effectively improved the jumping ability of volleyball players was plyometric training, and for balance ability improvement, whole body vibration exercise was effective. PMID:27313344

  1. Cohesion and Trauma: An Examination of a Collegiate Women's Volleyball Team

    ERIC Educational Resources Information Center

    Fletcher, Teresa B.; Meyer, Barbara B.

    2009-01-01

    This study examined the effects of Adventure Based Counseling (i.e., a low-element challenge program) on the cohesion of a collegiate women's volleyball team. Results suggest postintervention improvements in team cohesion. The support created in the challenge experience also transferred to the players helping one another to grieve the untimely…

  2. A Player-Centered Approach to Coaching

    ERIC Educational Resources Information Center

    de Souza, Adriano; Oslin, Judy

    2008-01-01

    The purpose of this article is to describe a player-centered approach (PCA), highlighting its qualities, and then to provide examples of its application in coaching and teaching sport. Most of the examples relate to the game of volleyball, but many of the recommendations and examples can be applied to most team sports. The article will conclude…

  3. Cumulative Incidence of Osteochondritis Dissecans of the Capitellum in Child and Adolescent Baseball Players

    PubMed Central

    Iwame, Toshiyuki; Matsuura, Tetsuya; Suzue, Naoto; Sairyo, Koichi

    2016-01-01

    Objectives: Prevalence of osteochondritis dissecans (OCD) of the capitellum is high among individuals who have played baseball since childhood. Recently two cross-sectional studies according to prevalence of OCD have been published. In a study of 1040 baseball players aged 10 to 12 years, Matsuura et al found that 2.1% of players had OCD, with no differences in prevalence according to age or player position. Kida et al., in their study of 2433 baseball players aged 12 to 18 years, found OCD in 3.4% of subjects. Furthermore, they found that players with OCD began playing baseball at earlier ages, had played for longer periods, and had experienced more elbow pain. The player’s current baseball position may not be related to the existence of OCD lesions. Together, these findings led us to examine the longitudinal study for examining the risk factors for occurrence of OCD. Our objectives were to determine (1) cumulative incidence rates of OCD in the school child players aged 6-11 years old, (2) the relative risk of OCD by age, beginning age playing baseball, playing period, experimental hours per week, playing position, and elbow pain. Methods: A total of 1,275 players aged 6-11 years (mean, 9.4 years) belonged to youth baseball teams without OCD lesions received examination in the next year and were the subjects of this investigation. Subjects were examined by questionnaire, and ultrasonographic and radiographic examination. Questionnaire items included age, player position, beginning age of playing baseball, playing period of baseball, number of training hours per week and history of elbow pain. Ultrasonography of the lateral aspect of the elbow was performed. An irregularity of the subchondral bone of the capitellum was regarded as an abnormality. Radiographic examination was recommended to players who had an abnormal finding on ultrasonographic examination. We investigated the following risk factors for occurrence of OCD: age, player position, beginning age of

  4. 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.

  5. Rhabdomyolysis After Out-of-Water Exercise in an Elite Adolescent Water Polo Player Carrying the IL-6 174C Allele Single-Nucleotide Polymorphism.

    PubMed

    Eliakim, Alon; Ben Zaken, Sigal; Meckel, Yoav; Yamin, Chen; Dror, Nitzan; Nemet, Dan

    2015-12-01

    We present an adolescent elite water polo player who despite a genetic predisposition to develop exercise-induced severe muscle damage due to carrying the IL-6 174C allele single-nucleotide polymorphism, developed acute rhabdomyolysis only after a vigorous out-of-water training, suggesting that water polo training may be more suitable for genetically predisposed athletes.

  6. [Nutritional status and physical condition of adolescent football players after consuming fishmeal as a nutritional complement].

    PubMed

    Accinelli-Tanaka, Roberto; López-Oropeza, Lidia

    2013-03-01

    The objective of the study is to identify the changes in the nutritional parameters and the physical condition of teenage players after eating fishmeal as a nutritional complement. For this purpose, a quasi-experimental study, blinded for investigators, was conducted, involving 100 teenage football players, divided in two groups, homogeneous in terms of all study parameters, one of which received fishmeal for four months. After evaluating the nutritional status and physical condition, before and after the intervention, no change was found in the nutritional and anthropometric status or laboratory results, or in the physical condition. However, those who received fishmeal did report a change in their hemoglobin and hematocrit levels in comparison to the control group. In conclusion, the consumption of fishmeal did not lead to changes in the nutritional status or the physical condition of teenage football players.

  7. Does athletic training in volleyball modulate the components of visual evoked potentials? A preliminary investigation.

    PubMed

    Zwierko, Teresa; Lubiński, Wojciech; Lesiakowski, Piotr; Steciuk, Hanna; Piasecki, Leszek; Krzepota, Justyna

    2014-01-01

    This longitudinal study investigated visual evoked potentials (VEPs) in 11 young female volleyball players who participated in extensive training for 2 years. The control group consisted of 7 age-matched female students who were not involved in any regular sports activity. Recordings of VEPs were performed twice: baseline recording (i.e., before training began) and after 2 years of systematic, volleyball-specific athletic training. The effect of athletic training on visual signal conductivity was assessed by recording the latency of N75, P100 and N135 components of the VEPs waveform. Extensive experience with volleyball training reduced signal conductivity time through visual pathway. Specifically, the latency of P100 was reduced on average by 2.2 ms during binocular viewing. Moreover, athletes had reduced N75 latency (difference of 3.3 ms) for visual stimuli that generated greater response from peripheral retina. These results indicate that sport training can affect very early sensory processing in athletes.

  8. Physical characteristics of elite adolescent female basketball players and their relationship to match performance

    PubMed Central

    Montalvo, Alicia; Latinjak, Alexander; Unnithan, Viswanath

    2016-01-01

    Abstract There were two aims of this study: first, to investigate physical fitness and match performance differences between under-16 (U16) and under-18 (U18) female basketball players, and second, to evaluate the relationship between physical fitness and game-related performances. Twenty-three young, female, elite Spanish basketball players (16.2 1.2 years) participated in the study. The sample was divided into two groups: U16 and U18 players. The average scores from pre- and post-season physical fitness measurements were used for subsequent analyses. Anthropometric variables were also measured. To evaluate game performance, game-related statistics, including the number of games and minutes played, points, rebounds, assists, steals and blocks per game, were recorded for every competitive match in one season. When anthropometric and physical performance variables were compared between groups, the U18 group demonstrated significantly (p<0.05) higher values in upper (+21.2%) and lower (+27.11%) limb strength compared to the U16 group. Furthermore, no significant differences between groups were observed in match performance outcomes. Only two performance variables, steals and assists per game, correlated significantly with jump capacity, speed, agility, anaerobic power, repeated sprint ability and aerobic power (p ≤ 0.005). These findings can help optimize training programs for young, elite female basketball players. PMID:28149421

  9. Basketball Performance Is Related to Maturity and Relative Age in Elite Adolescent Players.

    PubMed

    Torres-Unda, Jon; Zarrazquin, Idoia; Gravina, Leyre; Zubero, Jaime; Seco, Jesús; Gil, Susana M; Gil, Javier; Irazusta, Jon

    2016-05-01

    During a national championship, the anthropometric, physiological, and maturation characteristics of 13- to 14-year-old players of elite basketball teams and their association with sport performance were analyzed. Body parameters (weight, height, skinfold thicknesses, and lengths) were measured and physiological capacities assessed by sprint (20 m) and jump tests (i.e., countermovement jump with arm swing). Chronological age (CA) and maturity offset (years from age at peak height velocity; YAPHV) were calculated, and then predicted age at peak height velocity, as the difference between CA and YAPHV. Game performance was assessed with point averages and the performance index rating (PIR). The birth-date distribution of players was biased, those born early in the selection year outnumbering those born later. Anthropometric analysis indicated that players who performed better had longer body lengths. Physiological testing showed that semi-finalists had better sprint performance than quarter-finalists and those players with greater jump capacity scored more points. Early maturation and advanced maturity status were also associated with better PIR and scored points per game. Multiple blockwise regression analysis showed that, among the factors analyzed, YAPHV was the best predictor of basketball performance. In conclusion, around puberty, physical and physiological parameters associated with maturity and CA are important in determining the success of elite basketball players. Consequently, boys who are born in the second half of the year and/or late maturing tend to be marginalized or totally excluded, and not given the chance to play under equal conditions; their careers may then be held back by the relative disadvantage associated with inexperience.

  10. Comparison of Lateral Abdominal Muscle Thickness and Cross Sectional Area of Multifidus in Adolescent Soccer Players with and without Low Back Pain: A Case Control Study

    PubMed Central

    Noormohammadpour, Pardis; Hosseini Khezri, Alireza; Linek, Paweł; Mansournia, Mohammad Ali; Hassannejad, Alireza; Younesian, Ali; Farahbakhsh, Farzin; Kordi, Ramin

    2016-01-01

    Background Low back pain (LBP) is a common complaint amongst adolescent athletes. While different studies have shown association between LBP and trunk muscle thickness in the general population, few articles have studied it in adolescent athletes. Objectives The aim of this study is to compare lateral abdominal muscle thickness and function, and cross sectional area (CSA) of lumbar multifidus (LM) in adolescent soccer players with and without LBP. Methods In total, 28 adolescent soccer players with and without LBP, from the premier league participated in this study. The thickness of external oblique, internal oblique and transversus abdominis and the CSA of the LM muscles at L4 level on both sides were measured at rest and contraction via ultrasound imaging (USI). In addition, leg length discrepancy, hamstring flexibility, active lumbar forward flexion, and isometric muscle endurance of trunk extensors were measured in both groups. (study design/setting: case control study). Results The mean (SD) age in LBP group and non-LBP group were 14.0 (1.1) and 14.1 (0.9) years, respectively. There was no significant difference in baseline characteristics of participants between groups. Findings showed no significant difference between LBP and non-LBP groups comparing all measured variables. Conclusions The data obtained support that there is not a correlation between abdominal muscle thickness and CSA of the lumbar multifidi and LBP in adolescent soccer players. These findings suggest that other factors rather than the thickness of deep trunk muscles may play a more significant role in the etiology of LBP in adolescent soccer players. PMID:28144414

  11. Quantitative Evaluation of Growth Plates around the Knees of Adolescent Soccer Players by Diffusion-Weighted Magnetic Resonance Imaging

    PubMed Central

    Krajnc, Zmago; Rupreht, Mitja; Drobnič, Matej

    2015-01-01

    Purpose. To quantitatively evaluate growth plates around the knees in adolescent soccer players utilizing the diffusion-weighted MR imaging (DWI). Methods. The knees and adjacent growth plates of eleven 14-year-old male soccer players were evaluated by MRI before (end of season's summer break) and after two months of intense soccer training. MRI evaluation was conducted in coronal plane by PD-FSE and DWI. All images were screened for any major pathological changes. Later, central growth plate surface area (CGPSA) was measured and the apparent diffusion coefficient (ADC) values were calculated in two most central coronal slices divided into four regions: distal femur medial (DFM), distal femur lateral (DFL), proximal tibia medial (PTM), and proximal tibia lateral (PTL). Results. No gross pathology was diagnosed on MRI. CGPSA was not significantly reduced: DFM 278 versus 272, DFL 265 versus 261, PTM 193 versus 192, and PTL 214 versus 210. ADC decrease was statistically significant only for PTM: DFM 1.27 versus 1.22, DFL 1.37 versus 1.34, PTM 1.13 versus 1.03 (p = 0.003), and PTL 1.28 versus 1.22. Conclusions. DWI measurements indicate increased cellularity in growth plates around knees in footballers most prominent in PTM after intense training. No detectable differences on a standard PD-FSE sequence were observed. PMID:26693482

  12. Effects of Plyometric and Sprint Training on Physical and Technical Skill Performance in Adolescent Soccer Players.

    PubMed

    Sáez de Villarreal, Eduardo; Suarez-Arrones, Luis; Requena, Bernardo; Haff, Gregory G; Ferrete, Carlos

    2015-07-01

    To determine the influence of a short-term combined plyometric and sprint training (9 weeks) within regular soccer practice on explosive and technical actions of pubertal soccer players during the in-season. Twenty-six players were randomly assigned to 2 groups: control group (CG) (soccer training only) and combined group (CombG) (plyometric + acceleration + dribbling + shooting). All players trained soccer 4 times per week and the experimental groups supplemented the soccer training with a proposed plyometric-sprint training program for 40 minutes (2 days per weeks). Ten-meter sprint, 10-m agility with and without ball, CMJ and Abalakov vertical jump, ball-shooting speed, and Yo-Yo intermittent endurance test were measured before and after training. The experimental group followed a 9-week plyometric and sprint program (i.e., jumping, hurdling, bouncing, skipping, and footwork) implemented before the soccer training. Baseline-training results showed no significant differences between the groups in any of the variables tested. No improvement was found in the CG; however, meaningful improvement was found in all variables in the experimental group: CMJ (effect size [ES] = 0.9), Abalakov vertical jump (ES = 1.3), 10-m sprint (ES = 0.7-0.9), 10-m agility (ES = 0.8-1.2), and ball-shooting speed (ES = 0.7-0.8). A specific combined plyometric and sprint training within regular soccer practice improved explosive actions compared with conventional soccer training only. Therefore, the short-term combined program had a beneficial impact on explosive actions, such as sprinting, change of direction, jumping, and ball-shooting speed which are important determinants of match-winning actions in soccer performance. Therefore, we propose modifications to current training methodology for pubertal soccer players to include combined plyometric and speed training for athlete preparation in this sport.

  13. Management of Sport Injuries with Korean Medicine: A Survey of Korean National Volleyball Team

    PubMed Central

    Hwang, Eui-Hyoung; Kwon, Ojin

    2016-01-01

    The purpose of this study was to report the current state of Korean medicine (KM) treatment on sports injury by implementing survey with volleyball team medical doctors participating in 2013-2014 season. Six KM doctors completed a questionnaire that includes injury parameters: type, location, situation, and pain scores. We collected 166 injury cases from 94 Korean male and female national volleyball players. Knee (25.9%), low back (13.3%), elbow, and ankle (8.4%) injuries were most common. Joint (41.6%) and muscle (30.7%) were major injured tissues. KM team medical doctors utilized acupuncture (40.4%), chuna manual therapy (16.0%), physical therapy (15.2%), taping (9.0%), and cupping (7.8%) to treat volleyball injuries. Any types of medications were used infrequently. Additional physical and exercise therapy were preferred after receiving acupuncture (both 46.9%). This study presented the preliminary injury profile of Korean elite volleyball players. Injury and treatment parameters could be useful to build advanced KM model in sport medicine. PMID:27651819

  14. Volleyball injuries presenting in casualty: a prospective study.

    PubMed Central

    Solgård, L; Nielsen, A B; Møller-Madsen, B; Jacobsen, B W; Yde, J; Jensen, J

    1995-01-01

    During 1986, all sports injuries (n = 5222) were prospectively recorded at the two casualty departments in Arhus, Denmark. Volleyball injuries (n = 278) accounted for 5.3% of all sports injuries. An evaluation of the rehabilitation period and the consequences of the injuries was undertaken by questionnaire three years after the injury. The injury incidence was 1.9 injuries/1000 inhabitants/year. Hand, finger, and ankle sprains were the most frequent injuries. Female players had significantly more hand/finger injuries than male players, who incurred more ankle/foot injuries. Knee (6%) and ankle injuries (31%) were responsible for the longest duration of absence from sports participation. There were relatively few chronic injuries. The study suggests the need to enhance prophylactic measures with regard to blocking and overhand pass techniques, in order to reduce the number and extent of ankle and hand/finger injuries. PMID:8800857

  15. Are Tendinopathies really a common injury in volleyball?

    PubMed Central

    Bustos, Aldo; Locaso, Fernando

    2017-01-01

    Objectives: To perform a description of tendinopathies as an injury in volleyball high performance. Methods: An observational and prospective study was conducted from 2014-2016 in the senior Argentinian volleyball team. The same was held by two observers. Moreover, 78 athletes were evaluated. We support Dvorak’s claims that an injury is determined by the loss of at least one training session or a match. Results: 78 players were exposed to 21812 hours of training and matches. As a result 37 injuries were evaluated in 31 players. Taking into account tendinopathies, it can be said that 34 players consulted 412 times, showing a prevalence of 43.5% of the whole enquires but when we refer to the same pathology as injury the average lowers, presenting 8 lesions in 6 players and showing a prevalence of 7.6% as injuries. Incidence of tendon injuries is 0.32 per 1000 hours of exposure Tendon Injuries: 5 were patellar, 2 supraspinatus, 1 aquiles. 5 Slight, 2 moderate, 1 severe. Conclusion: Clearly, tendinopathy is a common problem in this sport but it is not a common cause of injury. This is demonstrated in prevalence rates whereas 43.5 % just consulted and 7,6 % suffer from real injuries. We think this might be due to several factors such as, advances in medical therapy, preventive protocols and increase in thresholds of pain that high-performance athletes can bear. In our experience this pathology was shown to be the third leading cause of injuries. In 2016 we did not deal with any case of injury for tendinopathy.

  16. Posttraumatic fat necrosis presenting as prepatellar loose bodies in an adolescent football player.

    PubMed

    Sole, Joshua S; Wisniewski, Steve J; Dahm, Diane L; Bond, Jeffrey; Smith, Jay

    2014-08-01

    A 16-year-old high school football player presented with 4 months of anterior knee pain and small, mobile, prepatellar "lumps" after falling onto an opponent's cleat. He reported knee pain primarily during knee flexion and direct pressure during squatting and kneeling. Knee radiographs were unremarkable. Ultrasonography revealed multiple, freely mobile, subcutaneous nodules of variable size and echogenicity in the prepatellar region. Analysis of magnetic resonance imaging suggested possible fat necrosis but was nondiagnostic. The patient opted for surgical exploration, at which time multiple, opalescent subcutaneous nodules were removed. Pathology was consistent with encapsulated fat necrosis. After surgery, his symptoms resolved, and he returned to sports without restrictions.

  17. Effect of Age Group on Technical-Tactical Performance Profile of the Serve in Men's Volleyball.

    PubMed

    García-de-Alcaraz, Antonio; Ortega, Enrique; Palao, José M

    2016-10-01

    The aim of this study was to analyze the technical-tactical performance profile of the serve for various age groups and categories of competition in men's volleyball. The sample comprised 13,262 serves performed by 986 players in 299 sets observed in various categories of competition (U-14, U-16, U-19, national senior, and international senior). An observational design was used. The variables studied were category of competition, type of execution, and serve performance. The results showed that for higher age groups (senior categories), there were significantly fewer jump serves and poorer serve performance, regardless of players' maturity and training development. The use of the jump serves increased the serve risk while attempting to hinder the organization of the opponent attack. This paper discusses the serve evolution and the implications on the training process at the different age groups in men's volleyball.

  18. Different temporal bases for body and arm movements in volleyball serve reception.

    PubMed

    Benerink, N H; Bootsma, R J; Zaal, F T J M

    2015-10-01

    In many sports, successfully intercepting a ball requires players to move both their body and their arms. Yet, studies of interception typically focus on one or the other. We performed an analysis of the moments of first foot and arm movements of elite-level volleyball players during serve reception. Video footage of five international matches of the Netherlands men's national volleyball team allowed the systematic coding and analysis of 347 different serve reception events. For each event, we identified the time of serve (TS) and time of contact (TC). Ball flight time (from TS to TC) varied between and within types of serve (power jump serves, n = 193, and jumping float serves, n = 154). Correlation analyses revealed that foot movement was initiated with respect to time from TS, while arm movement was initiated with respect to time until TC. These results suggest that whole-body and arm movements rely on different control processes.

  19. On- and Off-Field Antisocial and Prosocial Behavior in Adolescent Soccer Players: A Multilevel Study

    ERIC Educational Resources Information Center

    Rutten, Esther A.; Dekovic, Maja; Stams, Geert Jan J. M.; Schuengel, Carlo; Hoeksma, Jan B.; Biesta, Gert J. J.

    2008-01-01

    This study investigated to what extent team membership predicts on- and off-field antisocial and prosocial behavior in (pre)adolescent athletes. Effects of team-membership were related to characteristics of the team environment, such as relational support from the coach towards team members, fair play attitude and sociomoral reasoning within the…

  20. Effects of an off-season conditioning program on the physical characteristics of adolescent rugby union players.

    PubMed

    Smart, Daniel J; Gill, Nicholas D

    2013-03-01

    The aims of the study were to determine if a supervised off-season conditioning program enhanced gains in physical characteristics compared with the same program performed in an unsupervised manner and to establish the persistence of the physical changes after a 6-month unsupervised competition period. Forty-four provincial representative adolescent rugby union players (age, mean ± SD, 15.3 ± 1.3 years) participated in a 15-week off-season conditioning program either under supervision from an experienced strength and conditioning coach or unsupervised. Measures of body composition, strength, vertical jump, speed, and anaerobic and aerobic running performance were taken, before, immediately after, and 6 months after the conditioning. Post conditioning program the supervised group had greater improvements in all strength measures than the unsupervised group, with small, moderate and large differences between the groups\\x{2019} changes for chin-ups (9.1%; ± 11.6%), bench-press (16.9%; ± 11.7%) and box-squat (50.4%; ± 20.9%) estimated 1RM respectively. Both groups showed trivial increases in mass; however increases in fat free mass were small and trivial for supervised and unsupervised players respectively. Strength declined in the supervised group while the unsupervised group had small increases during the competition phase, resulting in only a small difference between the long-term changes in box-squat 1RM (15.9%; ± 13.2%). The supervised group had further small increases in fat free mass resulting in a small difference (2.4%; ± 2.7%) in the long-term changes. The postconditioning differences between the 2 groups may have been a result of increased adherence and the attainment of higher training loads during supervised training. The lack of differences in strength after the competition period indicates that supervision should be maintained to reduce substantial decrements in performance.

  1. 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

  2. Tactical Determinants of Setting Zone in Elite Men'S Volleyball

    PubMed Central

    Afonso, Jose; Esteves, Francisca; Araújo, Rui; Thomas, Luke; Mesquita, Isabel

    2012-01-01

    The interactions between two opposing teams lead to the emergence of unique game patterns. In volleyball, attack efficacy emerges as the strongest predictor of the final result and thus it becomes of foremost importance to understand which game patterns afford the attaining of higher attack efficacies. These rely on the quality of the setting action. In turn, the serve and the serve reception constrain the setter's actions and the attacker's efficacy. Therefore, the purpose of this study was to examine predictors of the setting zone in elite-level men's volleyball. Thirty-one matches of the 2007 World Cup were analyzed, in total 5117 rallies. The dependent variable was the setting zone, and the independent variables were the server player, serve type, serve direction, serve depth, reception zone, receiver player and reception type. Multinomial logistic regression was applied, in order to obtain the estimated likelihood of occurrence of the dependent variable, based on the values of the independent variables (p < 0.05). Only the serve direction showed not to be predictive of the setting zone. Concerning the remaining variables, the tennis jump serve, serves from the middle-player, deep serves, reception near the endline or sidelines, reception by the zone 4 attackers when in defensive zone, and low reception all proved to impair the quality of reception, demanding the setter to play more often in the not acceptable setting zone. Results suggest that, at this level, practice of serve-reception should preferably cover the deep tennis jump serve, and attempt to afford the libero more opportunities to receive. By focusing on the variables with the most predictive power, performers may better allocate their attention towards the most pertinent cues at each moment. Knowledge of these interactive models provides valuable insights into the dynamics of the action sequences, affording coaches important information and guidance. Key pointsA set of key variables interact and

  3. Tactical determinants of setting zone in elite men's volleyball.

    PubMed

    Afonso, Jose; Esteves, Francisca; Araújo, Rui; Thomas, Luke; Mesquita, Isabel

    2012-01-01

    The interactions between two opposing teams lead to the emergence of unique game patterns. In volleyball, attack efficacy emerges as the strongest predictor of the final result and thus it becomes of foremost importance to understand which game patterns afford the attaining of higher attack efficacies. These rely on the quality of the setting action. In turn, the serve and the serve reception constrain the setter's actions and the attacker's efficacy. Therefore, the purpose of this study was to examine predictors of the setting zone in elite-level men's volleyball. Thirty-one matches of the 2007 World Cup were analyzed, in total 5117 rallies. The dependent variable was the setting zone, and the independent variables were the server player, serve type, serve direction, serve depth, reception zone, receiver player and reception type. Multinomial logistic regression was applied, in order to obtain the estimated likelihood of occurrence of the dependent variable, based on the values of the independent variables (p < 0.05). Only the serve direction showed not to be predictive of the setting zone. Concerning the remaining variables, the tennis jump serve, serves from the middle-player, deep serves, reception near the endline or sidelines, reception by the zone 4 attackers when in defensive zone, and low reception all proved to impair the quality of reception, demanding the setter to play more often in the not acceptable setting zone. Results suggest that, at this level, practice of serve-reception should preferably cover the deep tennis jump serve, and attempt to afford the libero more opportunities to receive. By focusing on the variables with the most predictive power, performers may better allocate their attention towards the most pertinent cues at each moment. Knowledge of these interactive models provides valuable insights into the dynamics of the action sequences, affording coaches important information and guidance. Key pointsA set of key variables interact and

  4. Foveal and peripheral fields of vision influences perceptual skill in anticipating opponents' attacking position in volleyball.

    PubMed

    Schorer, Jörg; Rienhoff, Rebecca; Fischer, Lennart; Baker, Joseph

    2013-09-01

    The importance of perceptual-cognitive expertise in sport has been repeatedly demonstrated. In this study we examined the role of different sources of visual information (i.e., foveal versus peripheral) in anticipating volleyball attack positions. Expert (n = 11), advanced (n = 13) and novice (n = 16) players completed an anticipation task that involved predicting the location of volleyball attacks. Video clips of volleyball attacks (n = 72) were spatially and temporally occluded to provide varying amounts of information to the participant. In addition, participants viewed the attacks under three visual conditions: full vision, foveal vision only, and peripheral vision only. Analysis of variance revealed significant between group differences in prediction accuracy with higher skilled players performing better than lower skilled players. Additionally, we found significant differences between temporal and spatial occlusion conditions. Both of those factors interacted separately, but not combined with expertise. Importantly, for experts the sum of both fields of vision was superior to either source in isolation. Our results suggest different sources of visual information work collectively to facilitate expert anticipation in time-constrained sports and reinforce the complexity of expert perception.

  5. Increased Training Volume Improves Bone Density and Cortical Area in Adolescent Football Players.

    PubMed

    Varley, Ian; Hughes, David C; Greeves, Julie P; Fraser, William D; Sale, Craig

    2017-03-01

    Habitual football participation has been shown to be osteogenic, although the specific volume of football participation required to cause bone adaptations are not well established. The aim of the present study is to investigate tibial bone adaptations in response to 12 weeks of increased training volume in elite adolescents who are already accustomed to irregular impact training. 99 male adolescent elite footballers participated (age 16±0 y; height 1.76±0.66 m; body mass 70.2±8.3 kg). Tibial scans were performed using peripheral quantitative computed tomography immediately before and 12 weeks after an increase in football training volume. Scans were obtained at 4, 14, 38 and 66% of tibial length. Trabecular density (mg/cm(3)), cortical density (mg/cm(3)), cross-sectional area, cortical area (mm(2)), cortical thickness (mm) and strength strain index (mm(3)) were assessed. Trabecular (4%) and cortical density (14, 38%), cortical cross-sectional area (14, 38%), total cross-sectional area (66%), cortical thickness (14, 38%) and strength strain index (14, 38%) increased following 12 weeks of augmented volume training (P<0.05). Increased density of trabecular and cortical compartments and cortical thickening were shown following an increased volume of training. These adaptive responses may have been enhanced by the adolescent status of the cohort, supporting the role of early exercise intervention in improving bone strength.

  6. The prevalence of musculoskeletal pain and use of painkillers among adolescent male ice hockey players in Finland.

    PubMed

    Selanne, Harri; Ryba, Tatiana V; Siekkinen, Kirsti; Kyröläinen, Heikki; Kautiainen, Hannu; Hakonen, Harto; Mikkelsson, Marja; Kujala, Urho M

    2014-01-01

    Participating in competitive sport increases the risk for injuries and musculoskeletal pain among adolescent athletes. There is also evidence that the use of prescription drugs has increased among sport club athletes. The purpose of this study was to evaluate the use of painkillers among young male ice hockey players (IHP) in comparison to schoolboys (controls) and its relation to the prevalence of musculoskeletal pain and problems during activities and sleeping. Information was gathered through a questionnaire, completed by 121 IHP and compared to the responses of 618 age-matched controls. Results showed that monthly existing pain was at 82% for IHP, and 72% for controls, though IHP had statistically more musculoskeletal pain in their lower limbs (56% vs. 44%), lower back (54% vs. 35%), and buttocks (26% vs. 11%). There were no group differences in the neck, upper back, upper limb, or chest areas. The disability index was statistically similar for both groups, as musculoskeletal pain causing difficulties in daily activities and sleeping was reported by a minority of subjects. Despite this similarity, IHP used more painkillers than controls (18% vs. 10%). Further nuanced research is encouraged to compare athletes and non-athletes in relation to painkillers.

  7. A caffeinated energy drink improves jump performance in adolescent basketball players.

    PubMed

    Abian-Vicen, Javier; Puente, Carlos; Salinero, Juan José; González-Millán, Cristina; Areces, Francisco; Muñoz, Gloria; Muñoz-Guerra, Jesús; Del Coso, Juan

    2014-05-01

    This study aimed at investigating the effects of a commercially available energy drink on shooting precision, jump performance and endurance capacity in young basketball players. Sixteen young basketball players (first division of a junior national league; 14.9 ± 0.8 years; 73.4 ± 12.4 kg; 182.3 ± 6.5 cm) volunteered to participate in the research. They ingested either (a) an energy drink that contained 3 mg of caffeine per kg of body weight or (b) a placebo energy drink with the same appearance and taste. After 60 min for caffeine absorption, they performed free throw shooting and three-point shooting tests. After that, participants performed a maximal countermovement jump (CMJ), a repeated maximal jumps test for 15 s (RJ-15), and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Urine samples were obtained before and 30 min after testing. In comparison to the placebo, the ingestion of the caffeinated energy drink did not affect precision during the free throws (Caffeine = 70.7 ± 11.8 % vs placebo = 70.3 ± 11.0 %; P = 0.45), the three-point shooting test (39.9 ± 11.8 vs 38.1 ± 12.8 %; P = 0.33) or the distance covered in the Yo-Yo IR1 (2,000 ± 706 vs 1,925 ± 702 m; P = 0.19). However, the energy drink significantly increased jump height during the CMJ (38.3 ± 4.4 vs 37.5 ± 4.4 cm; P < 0.05) mean jump height during the RJ-15 (30.2 ± 3.6 vs 28.8 ± 3.4 cm; P < 0.05) and the excretion of urinary caffeine (1.2 ± 0.7 vs 0.1 ± 0.1 μg/mL; P < 0.05). The intake of a caffeine-containing energy drink (3 mg/kg body weight) increased jump performance although it did not affect basketball shooting precision.

  8. Accountability systems and instructional approaches in youth volleyball training.

    PubMed

    Pereira, Felismina; Mesquita, Isabel; Graça, Amândio

    2009-01-01

    The purpose of this study was to examine accountability systems operating in youth volleyball training sessions and to understand how those systems vary according to the instructional tasks and the nature of the information provided by coaches. Additionally, the interactive effect of the players' age group on accountability systems and instructional tasks will be inspected. Twenty-eight youth volleyball coaches (for under 14s and under 18s) were observed, one training session each. Systematic observation strategies were used to describe and analyse task presentation and task structure during practice. Results convey that the accountability systems implemented by coaches were mainly implicit and governed by opportunity rather than explicit performance criteria imparted in task presentation. Remarks on the quality of performance only occurred during ongoing practice. More often than not coaches showed no reaction when athletes did not accomplish the tasks, failing to convey consequential expectancy-demand-monitoring messages. The instructional approach was predominantly composed of informing tasks, of technical nature and general information, which can reflect a technique and generalist coach profile. These results indicate the presence of weak and ambiguous accountability system, also corroborated by positive correlations of extending tasks with the category without exigency task presentation as well as with no reaction to unaccomplished tasks. There were no notorious differences in accountability behaviours between players' age group. Key pointsAccountability systems implemented by coaches were mainly implicit and governed by opportunity rather than explicit performance criteria imparted in task presentation. Only during practice, coaches remark the performance quality, followed by participation/effort.The instructional approach was predominantly composed of informing tasks, of technical nature and general information, which can reflect a technique and generalist

  9. Overuse in volleyball training/practice: A review on shoulder and spine-related injuries.

    PubMed

    Seminati, Elena; Minetti, Alberto Enrico

    2013-01-01

    Overuse injuries are predominant in sports involving the repetition of similar movements patterns, such as in volleyball or beach volleyball, and they may represent as much a problem as do acute injuries. This review discusses the prevalence of two of the most common overuse-related injuries in volleyball: shoulder and back/spine injuries. Risk factors and the aetiology of these injuries are illustrated in order to make possible to initiate preventive programme or post-injuries solutions. Data collected from literature showed a moderately higher injury rate for overuse shoulder injuries compared to the back/spine (19.0 ± 11.2% and 16.8 ± 9.7%, respectively). These data could be underestimated, and future epidemiological studies should consider overuse injuries separately from the others, with new methodological approaches. In addition to age, biomechanical and anatomical features of a volleyball technique utilised in game and the amount of hours played are considered as the main risk factors for overuse upper limb injuries, both for professional and recreational athletes. Together with post-injuries solutions, great importance has to be placed on preventive programmes, such as preventive rehabilitation, stretching, adequate warm up, strength-power exercises, etc. Furthermore, it is particularly suggested that coaches and players work together in order to develop new game/training techniques that minimise stresses and range of motion of the principal anatomical structures involved, while maintaining athletes performance.

  10. The Effects of Two Instructional Models--Tactical and Skill Teaching--On Skill Development and Game Play, Knowledge, Self-Efficacy, and Student Perceptions in Volleyball

    ERIC Educational Resources Information Center

    Harrison, Joyce M.; Blakemore, Connie L.; Richards, Robert P.; Oliver, Jon; Wilkinson, Carol; Fellingham, Gilbert

    2004-01-01

    This study evaluated the effects of Skill Teaching and Tactical approaches on skill development, game play, knowledge, and self-efficacy for 169 high- and low-skilled players of 182 beginning university Volleyball students. Three instructors each taught one Tactical and one Skill Teaching class two days a week for 16 weeks. A random coefficients…

  11. Stature and jumping height are required in female volleyball, but motor coordination is a key factor for future elite success.

    PubMed

    Pion, Johan A; Fransen, Job; Deprez, Dieter N; Segers, Veerle I; Vaeyens, Roel; Philippaerts, Renaat M; Lenoir, Matthieu

    2015-06-01

    It was hypothesized that differences in anthropometry, physical performance, and motor coordination would be found between Belgian elite and sub-elite level female volleyball players using a retrospective analysis of test results gathered over a 5-year period. The test sample in this study consisted of 21 young female volleyball players (15.3 ± 1.5 years) who were selected to train at the Flemish Top Sports Academy for Volleyball in 2008. All players (elite, n = 13; sub-elite, n = 8) were included in the same talent development program, and the elite-level athletes were of a high to very high performance levels according to European competition level in 2013. Five multivariate analyses of variance were used. There was no significant effect of playing level on measures of anthropometry (F = 0.455, p = 0.718, (Equation is included in full-text article.)= 0.07), flexibility (F = 1.861, p = 0.188, (Equation is included in full-text article.)= 0.19), strength (F = 1.218, p = 0.355, (Equation is included in full-text article.)= 0.32); and speed and agility (F = 1.176, p = 0.350, (Equation is included in full-text article.)= 0.18). Multivariate analyses of variance revealed significant multivariate effects between playing levels for motor coordination (F = 3.470, p = 0.036, (Equation is included in full-text article.)= 0.59). A Mann-Whitney U test and a sequential discriminant analysis confirmed these results. Previous research revealed that stature and jump height are prerequisites for talent identification in female volleyball. In addition, the results show that motor coordination is an important factor in determining inclusion into the elite level in female volleyball.

  12. Situation-orientated recognition of tactical patterns in volleyball.

    PubMed

    Jäger, Jörg M; Schöllhorn, Wolfgang I

    2007-10-01

    One important factor for effective operations in team sports is the team tactical behaviour. Many suggestions about appropriate players' positions in different attack or defence situations have been made. The aims of this study were to develop a classification of offensive and defensive behaviours and to identify team-specific tactical patterns in international women's volleyball. Both the classification and identification of tactical patterns is done by means of a hierarchical cluster analysis. Clusters are formed on the basis of similarities in the players' positions on the court. Time continuous data of the movements, including the start and end points during a pass from the setter, are analysed. Results show team-specific patterns of defensive moves with assessment rates of up to 80%. Furthermore, the recognition of match situations illustrates a clear classification of attack and defence situations and even within different defence conditions (approximately 100%). Thus, this approach to team tactical analysis yields classifications of selected offensive and defensive strategies as well as an identification of tactical patterns of different national teams in standardized situations. The results lead us to question training concepts that assume a team-independent optimal strategy with respect to the players' positions in team sports.

  13. Relationship between landing strategy and patellar tendinopathy in volleyball

    PubMed Central

    Bisseling, Rob W; Hof, At L; Bredeweg, Steef W; Zwerver, Johannes; Mulder, Theo

    2007-01-01

    Objective The aetiology of patellar tendinopathy (jumper's knee) remains unclear. To see whether landing strategy might be a risk factor for the development of this injury, this study examined whether landing dynamics from drop jumps differed among healthy volleyball players (CON) and volleyball players with a jumper's knee. The patients with jumper's knee were divided into an asymptomatic group with a previous jumper's knee (PJK) and a symptomatic group with a recent jumper's knee (RJK). Methods Inverse dynamics analyses were used to estimate lower extremity joint dynamics from 30, 50 and 70 cm drop jumps in the three groups (CON, n = 8; PJK, n = 7; RJK, n = 9). A univariate repeated measures analysis of variance was used to compare the different landing techniques. Results Data analysis of the landing dynamics revealed that PJK showed higher knee angular velocities (p<0.01), and higher ankle plantar flexion moment loading rate (p<0.01). Furthermore, strong tendencies of higher loading rate of vertical ground reaction force (p = 0.05) and higher knee extensor moment loading rate (p = 0.08) were found compared with CON. Higher values for peak knee moment, peak knee power and knee work (all p<0.01) were found for CON compared with RJK. The comparison of the two jumper's knee groups yielded higher knee angular velocities (p<0.01), together with higher ankle plantar flexion and knee extensor moment loading rate (p<0.01 and p<0.05, respectively). Conclusion Where RJK used a landing technique to avoid high patellar tendon loading, PJK used a stiffer landing strategy, which may be a risk factor in the development of patellar tendinopathy. PMID:17224437

  14. The Relative Age Effect among Female Brazilian Youth Volleyball Players

    ERIC Educational Resources Information Center

    Okazaki, Fabio H. A.; Keller, Birgit; Fontana, Fabio E.; Gallagher, Jere D.

    2011-01-01

    In sports, the relative age effect (RAE) refers to performance disadvantages of children born late in the competition year compared to those with birthdays soon after the cutoff date. This effect is derived from age grouping, a strategy commonly used in youth sport programs. The purpose of age grouping is to decrease possible cognitive, physical,…

  15. Can Emotionally Intelligent Volleyball Players Be More Prone to Sportspersonship?

    ERIC Educational Resources Information Center

    Can, Suleyman

    2016-01-01

    Emotional intelligence concept has been examined by researchers in the field of education as well as field of sports. When emotional intelligence theory examined, it comes to mind that emotional intelligence can be related to moral behaviors in sport. In this regard, the question of "Can emotional intelligence predict sportspersonship…

  16. Effects of heavy resistance training on maximal and explosive force production, endurance and serum hormones in adolescent handball players.

    PubMed

    Gorostiaga, E M; Izquierdo, M; Iturralde, P; Ruesta, M; Ibáñez, J

    1999-10-01

    To determine the effects of 6-weeks of heavy-resistance training on physical fitness and serum hormone status in adolescents (range 14-16 years old) 19 male handball players were divided into two different groups: a handball training group (NST, n = 10), and a handball and heavy-resistance strength training group (ST, n = 9). A third group of 4 handball goalkeepers of similar age served as a control group (C, n = 4). After the 6-week training period, the ST group showed an improvement in maximal dynamic strength of the leg extensors (12.2%; P < 0.01) and the upper extremity muscles (23%; P < 0.01), while no changes were observed in the NST and C groups. Similar differences were observed in the maximal isometric unilateral leg extension forces. The height of the vertical jump increased in the NST group from 29.5 (SD 4) cm to 31.4 (SD 5) cm (P < 0.05) while no changes were observed in the ST and C groups. A significant increase was observed in the ST group in the velocity of the throwing test [from 71.7 (SD 7) km x h(-1) to 74.0 (SD 7) km x h(-1); P < 0.001] during the 6-week period while no changes were observed in the NST and C groups. During a submaximal endurance test running at 11 km x h(-1), a significant decrease in blood lactate concentration occurred in the NST group [from 3.3 (SD 0.9) mmol x l(-1) to 2.4 (SD 0.8) mmol x l(-1); P < 0.01] during the experiment, while no change was observed in the ST or C groups. Finally, a significant increase (P < 0.01) was noted in the testosterone:cortisol ratio in the C group, while the increase in the NST group approached statistical significance (P < 0.08) and no changes in this ratio occurred in the ST group. The present findings suggested that the addition of 6-weeks of heavy resistance training to the handball training resulted in gains in maximal strength and throwing velocity but it compromised gains in leg explosive force production and endurance running. The tendency for a compromised testosterone:cortisol ratio

  17. Strategies for the prevention of volleyball related injuries

    PubMed Central

    Reeser, J C; Verhagen, E; Briner, W W; Askeland, T I; Bahr, R

    2006-01-01

    Although the overall injury rate in volleyball and beach volleyball is relatively low compared with other team sports, injuries do occur in a discipline specific pattern. Epidemiological research has revealed that volleyball athletes are, in general, at greatest risk of acute ankle injuries and overuse conditions of the knee and shoulder. This structured review discusses both the known and suspected risk factors and potential strategies for preventing the most common volleyball related injuries: ankle sprains, patellar tendinopathy, and shoulder overuse. PMID:16799111

  18. Strategies for the prevention of volleyball related injuries.

    PubMed

    Reeser, J C; Verhagen, E; Briner, W W; Askeland, T I; Bahr, R

    2006-07-01

    Although the overall injury rate in volleyball and beach volleyball is relatively low compared with other team sports, injuries do occur in a discipline specific pattern. Epidemiological research has revealed that volleyball athletes are, in general, at greatest risk of acute ankle injuries and overuse conditions of the knee and shoulder. This structured review discusses both the known and suspected risk factors and potential strategies for preventing the most common volleyball related injuries: ankle sprains, patellar tendinopathy, and shoulder overuse.

  19. Volleyball Guide with Official Rules. July 1971 - July 1973.

    ERIC Educational Resources Information Center

    Wilde, Jackie, Ed.

    This guide for playing women's volleyball dated July 1971 - July 1973 details rules and standards as well as the Division for Girls and Women's Sports (DGWS) statement of beliefs. Specific articles dealing with teamwork, basic fundamentals, suggestions for beginners, a volleyball mini unit, and volleyball visual aids are included. The booklet…

  20. NAGWS Volleyball Rulebook, 1993. Official Rules & Interpretations/Officiating.

    ERIC Educational Resources Information Center

    1993

    The National Association for Girls and Women in Sport (NAGWS) Volleyball Rules are based on the United States Volleyball Rules, which in turn are adopted from the rules and interpretations of the International Volleyball Federation Rules. Following a foreword by Robertha Abney, NAGWS President, the publication is organized into six sections as…

  1. NAGWS Volleyball Rulebook, 1992. Official Rules & Interpretations/Officiating.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, Recreation and Dance, Reston, VA. National Association for Girls and Women in Sport.

    The National Association for Girls and Women in Sport (NAGWS) Volleyball Rules, are based on the United States Volleyball Rules, which in turn are adopted from the rules and interpretations of the International Volleyball Federation Rules. Following a foreword by Doris Hardy, NAGWS President, the publication is organized into five sections as…

  2. Bilateral Volleyball-Related Deformity of the Little Fingers: Mallet Finger and Clinodactyly Mimic

    PubMed Central

    Uslu, Mustafa; Solak, Kazim; Ozsahin, Mustafa; Uzun, Hakan

    2011-01-01

    A 14-year-old male high school volleyball player was seen to evaluate right- and left-hand little-finger distal interphalangeal joint deformity and pain. His symptoms began during his second season of competitive play. The distal interphalangeal (DIP) joints of the little fingers flexed 20-30°, and a 10-15° valgus deformity was seen at the same joints. Pain was relieved with rest but returned immediately after playing volleyball, so plain radiographs were obtained. The flexion and valgus deformity was obvious on plain radiographs and through a clinical examination. Thus, a bilateral little-finger distal phalanx base epiphysis injury was seen. This injury is characterized by a biplanar Salter Harris physeal injury; type 5 on anteroposterior radiographs and type 2 on lateral plain radiographs. The deformity occurred as a result of competitive volleyball play. To our knowledge, this is the first reported case of a bilateral biplanar physial injury of the base of distal phalanges of the little fingers. Flexion and valgus deformities of DIP joints are a result of repeated micro traumas around the physis. Key points As a result of repeated micro traumas to the physial region, flexion and valgus deformities of the distal interphalangeal (DIP) joints should be occurred. Sports injuries to the hand often require treatment in orthopedic departments to avoid permanent deformities. Short- or long-term functional results can be gained by simple splinting procedures and abstention from play. PMID:24149318

  3. SPECIFIC SITES OF BONE EXPANSION DEPEND ON THE LEVEL OF VOLLEYBALL PRACTICE IN PREPUBESCENT BOYS

    PubMed Central

    Zouch, M.; Zribi, A.; Bouajina, E.; Zaouali, M.; Tabka, Z.

    2013-01-01

    The purpose of this study was to investigate the effect of 18 months of high and low levels of volleyball practice on bone acquisition. 130 prepubescent boys (mean age 11.4 ± 0.7) were divided into a high-level training group (HLG), low-level training group (LLG), and controls. Bone mineral content (BMC) and bone area at the whole body, lumbar spine L2-L4, femoral neck of the dominant leg, and right and left radius were measured using dual-photon X-ray absorptiometry. Enhanced BMC resulted from high-training volleyball activity in all measured sites except the third left and right distal radius, which is not modified by low-level training in prepubescent players but it was accompanied by a bone area expansion in radius and weight-bearing sites for the HLG, and in legs, whole right and left radius for the LLG. Significant improvement of skeletal tissues is associated with the intensity and duration of volleyball training. PMID:24744493

  4. Which skills and factors better predict winning and losing in high-level men's volleyball?

    PubMed

    Peña, Javier; Rodríguez-Guerra, Jorge; Buscà, Bernat; Serra, Núria

    2013-09-01

    The aim of this study was to determine which skills and factors better predicted the outcomes of regular season volleyball matches in the Spanish "Superliga" and were significant for obtaining positive results in the game. The study sample consisted of 125 matches played during the 2010-11 Spanish men's first division volleyball championship. Matches were played by 12 teams composed of 148 players from 17 different nations from October 2010 to March 2011. The variables analyzed were the result of the game, team category, home/away court factors, points obtained in the break point phase, number of service errors, number of service aces, number of reception errors, percentage of positive receptions, percentage of perfect receptions, reception efficiency, number of attack errors, number of blocked attacks, attack points, percentage of attack points, attack efficiency, and number of blocks performed by both teams participating in the match. The results showed that the variables of team category, points obtained in the break point phase, number of reception errors, and number of blocked attacks by the opponent were significant predictors of winning or losing the matches. Odds ratios indicated that the odds of winning a volleyball match were 6.7 times greater for the teams belonging to higher rankings and that every additional point in Complex II increased the odds of winning a match by 1.5 times. Every reception and blocked ball error decreased the possibility of winning by 0.6 and 0.7 times, respectively.

  5. Vertical jump assessment on volleyball: a follow-up of three seasons of a high-level volleyball team.

    PubMed

    Borràs, Xantal; Balius, Xavier; Drobnic, Franchek; Galilea, Piero

    2011-06-01

    This is a longitudinal descriptive study whose purpose is to assess the physical state of male volleyball players competing at the international level, comparing their jump heights during 3 different seasons. National team sample relies upon trainer decisions, and it was different every season. There were 23, 15, and 13 players in the first, second, and third years, respectively. Subjects underwent a vertical test protocol consisting of rocket jump, squat jump (SJ), countermovement jump (CMJ), CMJ with arms (CMJa), and spike jump (DJb) at the preparation period of the national team season. In 2007, an extra evaluation was performed during the competitive period. A contact mat was used for the assessment. An increase of jump height was observed over the years, with SJ and DJb increasing significantly (FSJ = 5.4; FDJb = 4.7; p < 0.05). The elasticity index decreased significantly between 2007 and 2008 (FEI = 8.5; p < 0.05), whereas arm utilization index and approach index increased, but this increase was not statistically significant. A significant increase in SJ and DJb was also observed between the 2 tests performed in 2007, whereas a nonsignificant increase was observed for CMJ and CMJa. The results indicate a better performance of explosive strength, elastic-explosive strength, and reflex-elastic-explosive strength and a better use of arms during jumps.

  6. A case study of virilizing adrenal tumor in an adolescent female elite tennis player--insight into the use of anabolic steroids in young athletes.

    PubMed

    Eliakim, Alon; Cale-Benzoor, Mia; Klinger-Cantor, Beatrice; Freud, Enrique; Nemet, Dan; Feigin, Elad; Weintrob, Neomi

    2011-01-01

    A 14-year-old Caucasian girl was referred to the endocrine clinic for evaluation of voice deepening, facial hirsutism, and acne starting 2 years previously. She had been a competitive tennis player since age 7 years, practicing for 4-6 hours daily. On physical examination she was noticed to have a masculine appearance with mild facial acne and moderate hirsutism. Tanner stage was 1 for breast tissue and 5 for pubic hair. Her androgen levels (testosterone, androstenedione, dehydroepiandrosterone sulfate) were extremely elevated. Adrenal ultrasonography revealed a round left 4.6 × 5.3-cm adrenal mass. Laparoscopic left adrenalectomy was performed. The histologic findings were compatible with a benign adrenocortical tumor. Postoperatively, androgen levels dropped to within the normal range. Breast development proceeded normally, menarche occurred 2 months after tumor resection, and menses has been regular since then. Muscle strength of the dominant and nondominant upper and lower extremities was measured 1 month before surgery and 1 year later, using an isokinetic dynamometer (Biodex Systems II, Biodex, Shirley, NY, USA). There was no significant decrease in overall muscle strength after removal of the virilizing tumor and the marked drop in circulating androgens. In addition, the patient maintained her age category, number 1, national tennis ranking. The results suggest that even extremely high levels of tumor-related circulating androgens had no evident effect on muscle strength and competitive performance in a female adolescent tennis player. The lack of beneficial effect on performance in adolescents, combined with the potentially hazardous side effects of anabolic steroids, suggests that teenage athletes should avoid their use.

  7. Discriminatory power of game-related statistics in 14-15 year age group male volleyball, according to set.

    PubMed

    García-Hermoso, Antonio; Dávila-Romero, Carlos; Saavedra, Jose M

    2013-02-01

    This study compared volleyball game-related statistics by outcome (winners and losers of sets) and set number (total, initial, and last) to identify characteristics that discriminated game performance. Game-related statistics from 314 sets (44 matches) played by teams of male 14- to 15-year-olds in a regional volleyball championship were analysed (2011). Differences between contexts (winning or losing teams) and "set number" (total, initial, and last) were assessed. A discriminant analysis was then performed according to outcome (winners and losers of sets) and "set number" (total, initial, and last). The results showed differences (winning or losing sets) in several variables of Complexes I (attack point and error reception) and II (serve and aces). Game-related statistics which discriminate performance in the sets index the serve, positive reception, and attack point. The predictors of performance at these ages when players are still learning could help coaches plan their training.

  8. Relation between in-game role and service characteristics in elite women's volleyball.

    PubMed

    Quiroga, Miriam E; García-Manso, Juan M; Rodríguez-Ruiz, David; Sarmiento, Samuel; De Saa, Yves; Moreno, M Perla

    2010-09-01

    The aim of this study was to determine whether the in-game role of players (setter, outside, middle, or opposite player) in elite women's volleyball is significantly related to the characteristics of their service. The sample consisted of 1,300 service deliveries (total serves for all matches) made by players in the 8 teams participating in 2 Final 4 stages of the Indesit European Champions League. The variables recorded were in-game role of the server, service type, speed of delivery, service area, target zone, and effectiveness of delivery. Results showed a significant relation between the server's in-game role and service type (p players most commonly served from behind zone 1 (100 and 80% of serves, respectively), which they defended after serving. Similarly, middle players served most frequently from behind zone 5 (47% of serves), the zone they subsequently defended.

  9. The role of volleyball expertise in motor simulation.

    PubMed

    Tomasino, Barbara; Guatto, Elisa; Rumiati, Raffaella Ida; Fabbro, Franco

    2012-01-01

    We explored the impact of motor experience on the interaction between implicit motor simulation and language-processing. In an action familiarity judgment task, expert volleyball players, fans and novices were presented with semantically correct sentences describing possible and not possible motor actions, all as negative or positive contexts, e.g., "Don't shank!" or "Assist!". As processing negated action-phrases is known to reduce simulation states, exposure to negative or positive contexts was used here to test how simulation varies according to motor feasibility (possible, impossible) and experience (experts and fans). A significant group×stimulus×context interaction showed that athletes and fans, took longer to process negative than positive contexts for possible actions, compared to action-impossible sentences. In addition, experts were significantly faster and more accurate than fans and, in turn, they were both more accurate than novices. Thus, implicit motor simulation impacts on action-verb processing depending on (i) the domain-relevant expertise, (ii) the feasibility of the actions, and (iii) on whether scenes are presented in a negated context. These results suggest that the implicit triggering of motor representations is modulated by the context and it is tuned to people's motor repertoire, even when actions are described linguistically.

  10. Skilled players' and novices' difficulty anticipating left- vs. right-handed opponents' action intentions varies across different points in time.

    PubMed

    Loffing, Florian; Hagemann, Norbert; Schorer, Jörg; Baker, Joseph

    2015-04-01

    A left-handers' performance advantage in interactive sports is assumed to result from their relative rarity compared to right-handers. Part of this advantage may be explained by athletes facing difficulties anticipating left-handers' action intentions, particularly when anticipation is based on kinematic cues available at an early stage of an opponent's movement. Here we tested whether the type of volleyball attack is predicted better against right- vs. left-handed opponents' movements and whether such handedness effects are evident at earlier time points in skilled players than novices. In a video-based experiment volleyball players and novices predicted the type of shot (i.e., smash vs. lob) of left- and right-handed volleyball attacks occluded at six different time points. Overall, right-handed attacks were better anticipated than left-handed attacks, volleyball players outperformed novices, and performance improved in later occlusion conditions. Moreover, in skilled players the handedness effect was most pronounced when attacks were occluded 480 ms prior to hand-ball-contact, whereas in novices it was most evident 240 ms prior to hand-ball-contact. Our findings provide further evidence of the effect of an opponent's handedness on action outcome anticipation and suggest that its occurrence in the course of an opponent's unfolding action likely depends on an observers' domain-specific skill.

  11. Injury risk management plan for volleyball athletes.

    PubMed

    James, Lachlan P; Kelly, Vincent G; Beckman, Emma M

    2014-09-01

    Volleyball is an increasingly popular team sport. As with any competitive sport, there is an inherent risk of injury that must be recognized and collaboratively managed. This article provides a practical approach to the management of volleyball injuries within a team or organization. A brief review of the epidemiological data is presented which establishes (i) ankle sprain, (ii) shoulder overuse injury, (iii) patella tendinopathy, and (iv) anterior cruciate ligament injury as the primary injuries to address amongst these athletes. The interaction of modifiable and non-modifiable risk factors for these injuries are used to classify athletes into high-, medium- and low-risk groups. Targeted training interventions are suggested, based upon the risk level of the athlete, to minimize the occurrence of these injuries. Practical methods for integrating these activities into a training plan are also discussed.

  12. Effects of Posthypnotic Suggestions on the Overhand Volleyball Serve.

    ERIC Educational Resources Information Center

    Buckner, Rose; Wynn, Mary Jo

    This study determines effects of posthypnotic suggestions in dealing with attitudinal impediments of students performing the overhand volleyball serve. Subjects were 54 male and female college students enrolled in beginning volleyball. Subjects were assigned either to a control or to an experimental group. After four class sessions, a 10-trial…

  13. NAGWS Volleyball Guide, 1989. Official Rules & Interpretations/Officiating.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, Recreation and Dance, Reston, VA. National Association for Girls and Women in Sport.

    This booklet contains the official rules and interpretations for officiating in volleyball competitions. Section 1 states the National Association for Girls and Women in Sport (NAGWS) interscholastic and collegiate volleyball rules for 1989-90. Section 2 presents a summary and descriptions of officiating techniques and mechanics. Study questions…

  14. Development of a Valid Volleyball Skills Test Battery.

    ERIC Educational Resources Information Center

    Bartlett, Jackie; And Others

    1991-01-01

    Describes the development of the North Carolina State University Volleyball Skills Test Battery which offers accurate measurement of three volleyball skills (serve, forearm pass, and set). When physical educators tested 313 students, the battery objectively measured their abilities, providing a gamelike means of teaching, testing, grouping, and…

  15. NAGWS Volleyball Guide 1990: Official Rules & Interpretations/Officiating.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, Recreation and Dance, Reston, VA. National Association for Girls and Women in Sport.

    This guide presents the 1990 update of the National Association for Girls & Women in Sport (NAGWS) interscholastic and collegiate volleyball rules. It includes the official U.S. volleyball rules and a summary of rule changes, definitions of skills and fouls, and a summary of penalties. Officiating techniques and mechanics are covered with a…

  16. Epidemiology of Basketball, Soccer, and Volleyball Injuries in Middle-School Female Athletes

    PubMed Central

    Barber Foss, Kim D.; Myer, Greg D.; Hewett, Timothy E.

    2014-01-01

    Background An estimated 30 to 40 million school children participate in sports in the United States; 34% of middle-school participants become injured and seek medical treatment at an annual cost close to $2 billion. The purpose of the current study was to evaluate the injury incidence and rates in female athletes in the middle-school setting during the course of 3 seasons. Methods Female basketball, soccer, and volleyball players were recruited from a single county public school district in Kentucky consisting of 5 middle schools. A total of 268 female athletes (162 basketball, 26 soccer, and 80 volleyball) participated. Athletes were monitored for sports-related injury and number of athlete exposures (AEs) by an athletic trainer. Injury rates were calculated for specific types of injuries within each sport. Injury rates for games and practices were also calculated and compared for each sport. Results A total of 134 injuries were recorded during the 3 sport seasons. The knee was the most commonly injured body part (99 injuries [73.9%]), of which patellofemoral dysfunction (31.3%), Osgood-Schlatter disease (10.4%), and Sinding-Larsen-Johansson/patella tendinosis (9%) had the greatest incidence. The ankle was the second most commonly injured body part, accounting for 16.4% of all injuries. The overall rates of injury by sport were as follows: soccer, 6.66 per 1000 AEs; volleyball, 3.68 per 1000 AEs; and basketball, 2.86 per 1000 AEs. Conclusions Female middle-school athletes displayed comparable injury patterns to those seen in their high-school counterparts. Future work is warranted to determine the potential for improved outcomes in female middle-school athletes with access to athletic training services. Clinical Relevance As the participation levels and number of injuries continue to rise, middle-school athletes demonstrate an increasing need for medical services provided by a certified athletic trainer. PMID:24875981

  17. Application of a tri-axial accelerometer to estimate jump frequency in volleyball.

    PubMed

    Jarning, Jon M; Mok, Kam-Ming; Hansen, Bjørge H; Bahr, Roald

    2015-03-01

    Patellar tendinopathy is prevalent among athletes, and most likely associated with a high jumping load. If methods for estimating jump frequency were available, this could potentially assist in understanding and preventing this condition. The objective of this study was to explore the possibility of using peak vertical acceleration (PVA) or peak resultant acceleration (PRA) measured by an accelerometer to estimate jump frequency. Twelve male elite volleyball players (22.5 ± 1.6 yrs) performed a training protocol consisting of seven typical motion patterns, including jumping and non-jumping movements. Accelerometer data from the trial were obtained using a tri-axial accelerometer. In addition, we collected video data from the trial. Jump-float serving and spike jumping could not be distinguished from non-jumping movements using differences in PVA or PRA. Furthermore, there were substantial inter-participant differences in both the PVA and the PRA within and across movement types (p < 0.05). These findings suggest that neither PVA nor PRA measured by a tri-axial accelerometer is an applicable method for estimating jump frequency in volleyball. A method for acquiring real-time estimates of jump frequency remains to be verified. However, there are several alternative approaches, and further investigations are needed.

  18. 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

  19. Evaluation of postural asymmetry and gross joint mobility in elite female volleyball athletes.

    PubMed

    Vařeková, Renata; Vařeka, Ivan; Janura, Miroslav; Svoboda, Zdenek; Elfmark, Milan

    2011-09-01

    to the tightness of the soleus muscle suffering from chronic overloading and/or an inappropriate stretching methods. An inappropriate and/or insufficient compensatory exercise and stretching method or system could be the cause of their marked postural asymmetry as well. A detailed examination of posture and muscle imbalance performed by an experienced physician or physiotherapist as well as individually tailored compensatory exercises and a stretching system can be strongly recommended to all elite athletes, not only to volleyball players.

  20. A harmonic oscillator having “volleyball damping”

    NASA Astrophysics Data System (ADS)

    Mickens, R. E.; Oyedeji, K.; Rucker, S. A.

    2006-05-01

    Volleyball damping corresponds to linear damping up to a certain critical velocity, with zero damping above this value. The dynamics of a linear harmonic oscillator is investigated with this damping mechanism.

  1. Bridging the Gap in Volleyball. From Basic Instruction to Game Play.

    ERIC Educational Resources Information Center

    Dawson, Linda; Polvino, Geri

    1982-01-01

    Using volleyball "mini games," which emphasize, one at a time, skills needed to play volleyball, helps students to develop skills needed to play. Mini games described are: (1) forearm pass; (2) overhand pass; (3) overhand pass; (4) overhand serve; (5) mini volleyball; and (6) alternate court set-up. (CJ)

  2. Game-Related Volleyball Skills that Influence Victory

    PubMed Central

    Silva, Miguel; Lacerda, Daniel; João, Paulo Vicente

    2014-01-01

    The aim of the present study was to identify the volleyball skills that discriminate in favour of victory. Twenty-four games (n=24) from the Senior Men’s Volleyball World Championship played in Italy in 2010 were chosen and analyzed with Data Volley software. The discriminating function was used to identify the discriminating variables, using a canonical structuring coefficient of |SC| ≥ .30. The results suggest that service points, reception errors, and blocking errors were the discriminating variables that identify the final outcome of the match (victory/defeat). Moreover, successful service points were the major variable most likely associated with match success (victory). In this sense, increasing the effectiveness of service should be a top priority in coaching elite volleyball teams. PMID:25114744

  3. Body Composition of Elite Female Players in Five Different Sports Games

    PubMed Central

    Mala, Lucia; Maly, Tomas; Zahalka, František; Bunc, Vaclav; Kaplan, Ales; Jebavy, Radim; Tuma, Martin

    2015-01-01

    The goal of this study was to identify and compare body composition (BC) variables in elite female athletes (age ± years): volleyball (27.4 ± 4.1), softball (23.6 ± 4.9), basketball (25.9 ± 4.2), soccer (23.2 ± 4.2) and handball (24.0 ± 3.5) players. Fat-free mass (FFM), fat mass, percentage of fat mass (FMP), body cell mass (BCM), extracellular mass (ECM), their ratio, the percentage of BCM in FFM, the phase angle (α), and total body water, with a distinction between extracellular (ECW) and intracellular water, were measured using bioimpedance analysis. MANOVA showed significant differences in BC variables for athletes in different sports (F60.256 = 2.93, p < 0.01, η2 = 0.407). The results did not indicate any significant differences in FMP or α among the tested groups (p > 0.05). Significant changes in other BC variables were found in analyses when sport was used as an independent variable. Soccer players exhibited the most distinct BC, differing from players of other sports in 8 out of 10 variables. In contrast, the athletes with the most similar BC were volleyball and basketball players, who did not differ in any of the compared variables. Discriminant analysis revealed two significant functions (p < 0.01). The first discriminant function primarily represented differences based on the FFM proportion (volleyball, basketball vs. softball, soccer). The second discriminant function represented differences based on the ECW proportion (softball vs. soccer). Although all of the members of the studied groups competed at elite professional levels, significant differences in the selected BC variables were found. The results of the present study may serve as normative values for comparison or target values for training purposes. PMID:25964823

  4. The Effect of Recreational Activities on Self-Esteem Development of Girls in Adolescence

    ERIC Educational Resources Information Center

    Bayazit, Betül

    2014-01-01

    This study aimed to investigate the effect of recreational activities on self-esteem development of girls in adolescence. For this purpose, a total of 20 girls in adolescence period took part in the present study. Recreational activities program included bowling, patenga, orienteering, basketball, volleyball, badminton, ping-pong, dance, fun…

  5. Teaching Strategies for the Forearm Pass in Volleyball

    ERIC Educational Resources Information Center

    Casebolt, Kevin; Zhang, Peng; Brett, Christine

    2014-01-01

    This article shares teaching strategies for the forearm pass in the game of volleyball and identifies how they will help students improve their performance and development of forearm passing skills. The article also provides an assessment rubric to facilitate student understanding of the skill.

  6. Pediatric volleyball-related injuries treated in US emergency departments, 1990-2009.

    PubMed

    Pollard, Katherine A; Shields, Brenda J; Smith, Gary A

    2011-09-01

    This study describes the epidemiology of pediatric volleyball-related injuries treated in US hospital emergency departments. Data for children younger than 18 years obtained from the National Electronic Injury Surveillance System of the US Consumer Product Safety Commission from 1990 through 2009 were analyzed. An estimated 692 024 volleyball-related injuries to children younger than 18 years occurred during the study period. The annual number of injuries declined significantly by 23% during the study period; however, the annual injury rate remained unchanged, and the number of volleyball-related concussions/closed head injuries increased significantly. Upper (48%) and lower (39%) extremity injuries occurred most frequently, as did strains/sprains (54%). Contact with the net/pole was associated with concussions/closed head injury our findings indicate opportunities for making volleyball an even safer sport for children. Protective padding, complying with US volleyball standards, should cover all volleyball poles and protruding hardware to prevent impact-related injuries.

  7. Inducing Attitude Change toward Online Gaming among Adolescent Players Based on Dissonance Theory: The Role of Threats and Justification of Effort

    ERIC Educational Resources Information Center

    Wan, Chin-Sheng; Chiou, Wen-Bin

    2010-01-01

    The negative impact of online gaming on adolescents has received much attention. The question of how to reduce their pathological use of online gaming is a critical issue. Based on the concept of external justification in dissonance theory, this experimental study aimed to examine whether severity of threat and justification of effort would impact…

  8. The Perceptual Cognitive Processes Underpinning Skilled Performance in Volleyball: Evidence From Eye-Movements and Verbal Reports of Thinking Involving an in Situ Representative Task

    PubMed Central

    Afonso, José; Garganta, Jêlio; Mcrobert, Allistair; Williams, Andrew M.; Mesquita, Isabel

    2012-01-01

    An extensive body of work has focused on the processes underpinning perceptual-cognitive expertise. The majority of researchers have used film-based simulations to capture superior performance. We combined eye movement recording and verbal reports of thinking to explore the processes underpinning skilled performance in a complex, dynamic, and externally paced representative volleyball task involving in situ data collection. Altogether, 27 female volleyball players performed as centre backcourt defenders in simulated sessions while wearing an eye-tracking device. After each sequence, athletes were questioned concerning their perception of the situation. The visual search strategies employed by the highly-skilled players were more exploratory than those used by skilled players, involving more fixations to a greater number of locations. Highly-skilled participants spent more time fixating on functional spaces between two or more display areas, while the skilled participants fixated on the ball trajectory and specific players. Moreover, highly-skilled players generated more condition concepts with higher levels of sophistication than their skilled counterparts. Findings highlight the value of using representative task designs to capture performance in situ. Key pointsDecision-making in complex sports relies deeply on perceptual-cognitive expertise. In turn, the effect of expertise is highly dependent on the nature and complexity of the task.Nonetheless, most researchers use simple tasks in their research designs, risking not capturing performance in a meaningful way. We proposed to use a live action setting with a complex task design, representative of real world situations.We combined eye movement registration with collection of immediate retrospective verbal reports. Although the two data sets are not directly comparable, they may be used in a complementary manner, providing a deeper and fuller understanding of the processes underpinning superior performance

  9. [Hematologic features of olympic volley-ball athletes].

    PubMed

    Faintuch, J J; Lotufo, P A; Gilberto, J

    1994-01-01

    Athletes tend to have lower hemoglobin concentrations than sedentary counterparts. Sports anemia is used to describe both pseudodilutional anemia and the true anemia of athletes. Pseudodilutional anemia is a beneficial adaptation to endurance training; the two most common causes of true anemia are iron deficiency and intravascular hemolysis. We used questionnaires, physical examination and laboratory investigation to study 16 volley-ball highly trained athletes and 23 outpatients with the same ages and gender that have not had any significant disease. All athletes and patients had Hb > 13 g/dl; the athletes hab Hb and hematocrit lower than the control patients; 25% of the athletes had both total and indirect bilirubin increased. Seven patients and only one athlete had intestinal parasitic infestation. These data support the idea that in São Paulo-Brazil among athletes overt anemia is uncommon but the volleyball athletes are in a borderline anemic state.

  10. [Effect of phlebodium decumanum and coenzyme Q10 on sports performance in professional volleyball players].

    PubMed

    García Verazaluce, Juan José; Vargas Corzo, María Del Carmen; Aguilar Cordero, María José; Ocaña Peinado, Francisco; Sarmiento Ramírez, Álvaro; Guisado Barrilao, Rafael

    2014-10-03

    Introducción: Los programas de entrenamiento físico, se basan en provocar estados de fatiga transitoria para inducir supercompensaciones de los sistemas biológicos implicados en la actividad, con el objeto mejorar el rendimiento del deportista a medio-largo plazo. La administración de suplementos nutricionales con propiedades antioxidantes e inmunomoduladoras, como Phlebodium decumanum y Coenzima Q10, constituyen medidas muy ventajosas para la recuperación de la inflamación y el daño tisular originados por el estrés del ejercicio intenso y mantenido. Metodología: Se llevó a cabo un diseño experimental, longitudinal, a doble ciego, con tres grupos randomizados a partir de una muestra de 30 jugadores varones de voleibol (22-32 años) de la Universidad de Granada, con un nivel de entrenamiento alto (17 horas por semana en los 6 meses previos a la investigación). Se evaluaron los efectos de un programa de entrenamiento físico de un mes de duración, común a todos los grupos de estudio, asociado a la administración simultánea de suplementos nutricionales a base de Phlebodium decumanum (4 cápsulas de 400 mg/ cáp. al día) el Grupo Experimental 1, Phlebodium decumanum (la misma dosis y posología que el grupo 1) más Coenzima Q10 (4 cápsulas de 30 mg/cáp al día) el Grupo Experimental 2, y sustancia placebo, el Grupo Control. Las variables dependientes sanguíneas para valorar los efectos de dicha intervención sobre el perfil endocrinometabólico e inmunológico basales fueron: cortisol e interleuquina 6 relacionados ambos con el eje del estrés inducido por el ejercicio, y ácido láctico y amonio, vinculados esencialmente, al metabolismo energético anaeróbio. Resultados: Todos los grupos del estudio manifestaron cambios adaptativos favorables sobre el perfil endocri no- metabólico e inmunológico, que se objetivaron a través de un descenso significativo basal postest de las concentraciones de cortisol, interleuquina 6, ácido láctico y amoniaco, respecto a los valores previos a la intervención actividad física ± suplemención nutricional protocolizada. Los grupos que mostraron un perfil más favorable, fueron los que recibieron suplementación nutricional frente a placebo, y de entre los primeros, los sujetos que tomaron doble suplementación con Phlebodium decumanum más Coenzima Q10. Conclusiones: La ingesta de Phlebodium decumanum y de Coenzima Q10 durante 4 semanas, mostró efectos protectores sobre el perfil endocrino-metabólico e inmunológico basales, que atribuimos a las propiedades inmunomoduladoras y antioxidantes de ambas sustancias, lo que no sólo resulta altamente beneficioso para retrasar la fatiga y mejorar el rendimiento deportivo, sino también, para disminuir el riesgo de lesiones asociadas al ejercicio físico de alta intensidad.

  11. The Construction and Analysis of a Test Battery Related to Volleyball Playing Capacity in Females.

    ERIC Educational Resources Information Center

    Disch, James G.; And Others

    The purpose of this report was to analyze a test battery constructed to describe and predict volleyball playing capacity in college and high school women. The following criteria were used for selecting a test for initial inclusion into the battery: (1) The test is related to a basic motor ability important to playing volleyball; (2) The test can…

  12. Students' Game Performance Improvements during a Hybrid Sport Education-Step-Game-Approach Volleyball Unit

    ERIC Educational Resources Information Center

    Araújo, Rui; Mesquita, Isabel; Hastie, Peter; Pereira, Cristiana

    2016-01-01

    The purpose of this study was to examine a hybrid combination of sport education and the step-game-approach (SGA) on students' gameplay performance in volleyball, taking into account their sex and skill-level. Seventeen seventh-grade students (seven girls, 10 boys, average age 11.8) participated in a 25-lesson volleyball season, in which the…

  13. Vortex-induced dynamic loads on a non-spinning volleyball

    NASA Astrophysics Data System (ADS)

    Qing-ding, Wei; Rong-sheng, Lin; Zhi-jie, Liu

    1988-09-01

    An experiment on vortex-induced dynamic loads on a non-spinning Volleyball was conducted in a wind tunnel. The flow past the Volleyball was visualized, and the aerodynamic load was measured by use of a strain gauge balance. The separation on the Volleyball was measured with hot-film. The experimental results suggest that under the action of an unstable tail vortex system the separation region is changeable, and that the fluctuation of drag and lateral forces is the same order of magnitude as the mean drag, no matter whether the seam of the Volleyball is symmetric or asymmetric, with regard to the flow. Based on the experimental data a numerical simulation of Volleyball swerve motion was made.

  14. Attack and serve performances according to the match period and quality of opposition in elite volleyball matches.

    PubMed

    Marcelino, Rui O; Sampaio, Jaime E; Mesquita, Isabel M

    2012-12-01

    The purpose of this study was to examine attack and serve performances in the beginning and end of the initial and final sets of volleyball matches according to the quality of opposition. Six hundred rallies from the Men's World Cup 2007 were selectively sampled from a total of 5,117 rallies observed using video match analysis. Rally-by-rally double moving averages of serve and attack efficacy were plotted by 4 different match periods (first 15 rallies of the initial set; first 15 rallies of the final set; last 15 rallies of the initial set; and last 15 rallies of the final set). Approximate entropy values were calculated to analyze the amount of data randomness. The results were examined according to the quality of opposition in 2 types of games: higher level (HIGH) including the first 4 ranked teams and lower level (LOW) composed of the last 5 ranked teams. The results suggested that volleyball matches presented different profiles depending on the match period. Considering the teams' level, a greater adaptation was found within the HIGH × HIGH matches according to the match period and a more strategic use of the serve and attack tactics taking into account the type of the set (initial or final set) and the period (beginning or end of the set). The findings emphasize the need for coaches and players to perceive the most important points at the end of the set and to manage their effort throughout the match attempting to reach this period in optimal condition. Therefore, it might be beneficial to coaches to stress the need to perform at the highest level, particularly at the end of the training drills that simulate competition scenarios.

  15. Comparison of inflammatory responses and muscle damage indices following a soccer, basketball, volleyball and handball game at an elite competitive level.

    PubMed

    Souglis, A; Bogdanis, G C; Giannopoulou, I; Papadopoulos, Ch; Apostolidis, N

    2015-01-01

    Inflammatory responses and muscle damage indices were compared between four popular team sports at an elite level. Seventy two male elite players of four team sports: soccer (n = 18), basketball (n = 18), volleyball (n = 18) and handball (n = 18), completed an official match, while 18 non-athletes served as controls. Blood samples were drawn before, immediately after and 13 and 37 h post-match. Soccer produced the greatest increase in inflammatory cytokines (tumor necrosis factor-alpha and interleukin-6), which were increased by 3-4 fold immediately after the game, as well as in C-reactive protein, which was increased by threefold in the next morning after the match. Metabolic stress (urea, ammonia and cortisol) and muscle damage indices (creatine kinase and lactate dehydrogenase) were also higher after soccer, with creatine kinase responses being almost 2-3 times higher than the other sports. Volleyball showed the smallest increase in inflammation and muscle damage markers compared with the other three sports.

  16. 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

  17. Rectus abdominis muscle injuries in elite handball players: management and rehabilitation.

    PubMed

    Balius, Ramon; Pedret, Carles; Pacheco, Laura; Gutierrez, Josep Antoni; Vives, Joan; Escoda, Jaume

    2011-01-01

    Muscle injuries generally occur in two-joint muscles with a high percentage of type II fibers during the performance of eccentric activity. Some muscle injuries, such as those located in the adductor longus, a monoarticular muscle, as well as rectus abdominis do not fully comply with these requirements. This study examines five cases of elite handball players with ruptured rectus abdominals. Sonographically, lesions in rectus abdominis are shown as a disruption of the fibrillar pattern with a hematic suffusion that invades the entire lesion. In some of the cases, the ultrasound study was complemented with a MRI. A unified rehabilitation protocol was applied and the return to play time of each handball player ranged between 16 and 22 days, with an average of 18.2 days. Follow-up at 15 months showed no evidence of re-injury or residual discomfort and all of them are playing at their highest level. The aim of this study was to illustrate a feature of handball injury that, as in tennis and volleyball, is uncommon and so far has not been specifically reported. The phenomenon of contralateral abdominal hypertrophy in handball appears in the dominant arm as in tennis and volleyball.

  18. Rectus abdominis muscle injuries in elite handball players: management and rehabilitation

    PubMed Central

    Balius, Ramon; Pedret, Carles; Pacheco, Laura; Gutierrez, Josep Antoni; Vives, Joan; Escoda, Jaume

    2011-01-01

    Muscle injuries generally occur in two-joint muscles with a high percentage of type II fibers during the performance of eccentric activity. Some muscle injuries, such as those located in the adductor longus, a monoarticular muscle, as well as rectus abdominis do not fully comply with these requirements. This study examines five cases of elite handball players with ruptured rectus abdominals. Sonographically, lesions in rectus abdominis are shown as a disruption of the fibrillar pattern with a hematic suffusion that invades the entire lesion. In some of the cases, the ultrasound study was complemented with a MRI. A unified rehabilitation protocol was applied and the return to play time of each handball player ranged between 16 and 22 days, with an average of 18.2 days. Follow-up at 15 months showed no evidence of re-injury or residual discomfort and all of them are playing at their highest level. The aim of this study was to illustrate a feature of handball injury that, as in tennis and volleyball, is uncommon and so far has not been specifically reported. The phenomenon of contralateral abdominal hypertrophy in handball appears in the dominant arm as in tennis and volleyball. PMID:24198573

  19. Impact of fluid restriction and ad libitum water intake or an 8% carbohydrate-electrolyte beverage on skill performance of elite adolescent basketball players.

    PubMed

    Carvalho, Pedro; Oliveira, Bruno; Barros, Renata; Padrão, Patricia; Moreira, Pedro; Teixeira, Vitor Hugo

    2011-06-01

    Twelve adolescent athletes underwent, in a crossover-design study, 3 separate 90-min training sessions in the following conditions: no fluid ingestion allowed (NF), ad libitum ingestion of water (W), and ad libitum ingestion of a commercial 8% carbohydrate-electrolyte sports beverage (CSB). After each session athletes performed a set of basketball drills (2-point, 3-point, and free-throw shootout, suicide sprints, and defensive zigzags). Body weight (before and after sessions), rating of perceived exertion (RPE), urine color, and beverage acceptability were determined in each session. Athletes also completed a survey about their knowledge and behaviors regarding hydration and fluid replacement. The percentage of weight loss was significantly higher in NF (2.46% ± 0.87%) than in the other 2 conditions (W, 1.08% ± 0.67%, p = .006; CSB, 0.65% ± 0.62%, p = .001) but also higher in W than CSB (p = .012). RPE was higher in NF (16.8 ± 1.96) than in the W (14.2 ± 1.99, p = .004) and CSB (13.3 ± 2.06, p = .002) trials. Athletes' fluid intake was positively correlated with proper self-reported behaviors (r = .75, p = .005) and knowledge (r = .76, p = .004) about fluid and hydration. In conclusion, fluid restriction during exercise was associated with a greater level of dehydration and increased perceived exertion but had no impact on basketball performance compared with ad libitum drinking of water or a CSB. Athletes with more knowledge about hydration and better self-reported hydration behaviors ingested more fluids during training sessions.

  20. Structural and electronic stability of a volleyball-shaped B80 fullerene

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Qian

    2010-10-01

    We have studied the structural and electronic characteristics of a volleyball-shaped B80 cage using first-principles density-functional calculations. In contrast to the popularly ratified “magic” B80 buckyball with 20 hexagonal pyramids and 12 hollow pentagons, the volleyball-shaped B80 constitutes 12 pentagonal pyramids, 8 hexagonal pyramids, and 12 hollow hexagons. The B80 volleyball is markedly more stable than the previously assumed magic B80 buckyball, which is attributed to the improved aromaticity associated with the distinct configuration.

  1. Celiac Disease in an Elite Female Collegiate Volleyball Athlete: A Case Report

    PubMed Central

    Eberman, Lindsey E; Cleary, Michelle A

    2005-01-01

    Objective: To present the case of an elite female volleyball player who complained of diarrhea and fatigue after preseason training. Background: The athlete lost 8.1 kg during the first 20 days of training, and we initially suspected an eating disorder. The sports medicine team interviewed the athlete and found she did not have psychological symptoms indicative of an eating disorder. The results of routine blood tests revealed critically high platelet counts; in conjunction with the physical findings, the athlete was referred to a gastroenterologist. Differential Diagnosis: Our initial suggestion was an eating disorder. Therefore, the differential diagnosis included anorexia athletica, anorexia nervosa, and bulimia nervosa. On referral, the differential diagnosis was anemia, gastrointestinal dysfunction, lymphoma, or bowel adenocarcinoma. Diarrhea, weight loss, and blood test results were suggestive of active celiac disease, and a duodenal biopsy specimen confirmed this diagnosis. Treatment: The athlete was treated with a gluten-free diet, which excludes wheat, barley, and rye. Dietary substitutions were incorporated to maintain adequate caloric intake. Uniqueness: The presence of active celiac disease may not be uncommon. However, elite athletes who face celiac disease present a new challenge for the athletic trainer. The athletic trainer can help guide the athlete in coping with the lifestyle changes associated with a gluten-free diet. Conclusions: One in every 200 to 400 individuals has celiac disease; many of these individuals are asymptomatic and, therefore, their conditions are undiagnosed. Undiagnosed, untreated celiac disease and patients who fail to follow the gluten-free diet increase the risk of further problems. PMID:16404459

  2. Comparison of the Traditional, Swing, and Chicken Wing Volleyball Blocking Techniques in NCAA Division I Female Athletes

    PubMed Central

    Neves, Taubi J.; Johnson, Wayne A.; Myrer, J. William; Seeley, Matthew K.

    2011-01-01

    In volleyball, blocking is highly correlated with team success. The identification of specific techniques that produce a more successful block would be helpful knowledge for coaches and players. This study compared the traditional, swing, and “chicken wing” blocking techniques in combination with the running step footwork pattern in order to determine which technique enabled athletes to perform a more effective block. High-speed videography (7 cameras, Vicon Motion Analysis System) was used to capture the blocking movements of thirteen female NCAA Division I athletes (age = 19.4 ± 1.19 years, height = 1.82 ± 0.08 m, mass = 70.63 ± 7.96 kg, and years of participation at the collegiate level = 2.23 ± 1.17 years). Each player was familiar with each blocking technique. Reflective markers were placed on the players and in randomized order the players performed 3 blocking trials of each technique. The following dependent variables were assessed: The time it took the athletes to get off the ground and get their hands above (vertically) the net was calculated. The distance the hand reached over the net or hand penetration (displacement between the net and finger in the anterior and vertical planes) was also measured. Lastly, jump height was calculated. Repeated measures ANOVA and post-hoc comparisons were done (α = 0.05). There was no significant difference in the main effect for time to get off the ground (p > 0.05). There was a significant difference in the time to get the hands above the net (p < 0.05). The swing block was best for jump height (p <.001) and hand penetration (p < 0.05). These results can help coaches and players decide which blocking technique will benefit them most as a blocking team and as individual blockers. Key points The swing blocking technique resulted in greater jump heights and increased hand penetration, relative to the traditional and chicken wing blocking techniques. The chicken wing blocking technique resulted in greater jump

  3. Sex differences in discriminative power of volleyball game-related statistics.

    PubMed

    João, Paulo Vicente; Leite, Nuno; Mesquita, Isabel; Sampaio, Jaime

    2010-12-01

    To identify sex differences in volleyball game-related statistics, the game-related statistics of several World Championships in 2007 (N=132) were analyzed using the software VIS from the International Volleyball Federation. Discriminant analysis was used to identify the game-related statistics which better discriminated performances by sex. Analysis yielded an emphasis on fault serves (SC = -.40), shot spikes (SC = .40), and reception digs (SC = .31). Specific robust numbers represent that considerable variability was evident in the game-related statistics profile, as men's volleyball games were better associated with terminal actions (errors of service), and women's volleyball games were characterized by continuous actions (in defense and attack). These differences may be related to the anthropometric and physiological differences between women and men and their influence on performance profiles.

  4. The Importance of Strength, Speed, and Body Size for Team Success in Women's Intercollegiate Volleyball.

    ERIC Educational Resources Information Center

    Morrow, James R., Jr.; And Others

    1979-01-01

    In evaluating performance of women's volleyball teams it was found that the quality of physical size as represented by body composition and strength was more important than the combination of height and lean weight. (JD)

  5. Cross-sectional area of psoas major muscle and hip flexion strength in youth soccer players.

    PubMed

    Hoshikawa, Yoshihiro; Iida, Tomomi; Ii, Nozomi; Muramatsu, Masataka; Nakajima, Yoshiharu; Chumank, Kentaro; Kanehisa, Hiroaki

    2012-10-01

    This study aimed to clarify the differences in the cross-sectional area (CSA) of the psoas major (PM) muscle and hip flexion force (HFF) of the right (dominant) side between adolescent male soccer players and age-matched non-athletes. PM CSA at L4–L5 and HFF at 1.05 rad/s were determined in 22 early (12.8–13.6 years) and 27 late (16.1–17.9 years) adolescent soccer players and 11 early (12.6–13.5 years) and 20 late (16.0–17.7 years) adolescent non-athletes. Fat-free mass (FFM) was greater in late adolescent soccer players than in late adolescent non-athletes, but was similar between the two early adolescent groups. Without the effect of age, PM CSA and HFF were greater in soccer players than in non-athletes. PM CSA and HFF were significantly correlated to FFM (soccer players, r = 0.860, P < 0.0001; non-athletes, r = 0.709, P < 0.0001) and PM CSA (soccer players, r = 0.760, P < 0.0001; non-athletes, r = 0.777, P < 0.0001), respectively. The difference between soccer players and non-athletes in PM CSA was still significant even when PM CSA was covaried for FFM. On the other hand, HFF covaried for PM CSA was similar between the two groups. The current results indicate that, as compared to age-matched non-athletes: (1) not only late, but also early adolescent soccer players have a greater PM CSA even when the difference in FFM was adjusted, and (2) their superiority in hip flexion force can be attributed to the difference in PM CSA.

  6. H:Q Ratios and Bilateral Leg Strength in College Field and Court Sports Players

    PubMed Central

    Cheung, Roy T.H.; Smith, Andrew W.; Wong, Del P.

    2012-01-01

    One of the key components in sports injury prevention is the identification of imbalances in leg muscle strength. However, different leg muscle characteristics may occur in large playing area (field) sports and small playing area (court) sports, which should be considered in regular injury prevention assessment. This study examined the isokinetic hamstrings-to-quadriceps (H:Q) ratio and bilateral leg strength balance in 40 male college (age: 23.4 ± 2.5 yrs) team sport players (field sport = 23, soccer players; court sport = 17, volleyball and basketball players). Five repetitions of maximal knee concentric flexion and concentric extension were performed on an isokinetic dynamometer at two speeds (slow: 60°·s−1 and fast: 300°·s−1) with 3 minutes rest between tests. Both legs were measured in counterbalanced order with the dominant leg being determined as the leg used to kick a ball. The highest concentric peak torque values (Nm) of the hamstrings and quadriceps of each leg were analyzed after body mass normalization (Nm·kg−1). Court sport players showed significantly weaker dominant leg hamstrings muscles at both contraction speeds (P < 0.05). The H:Q ratio was significantly larger in field players in their dominant leg at 60°·s−1 (P < 0.001), and their non-dominant leg at 300°·s−1 (P < 0.001) respectively. Sport-specific leg muscle strength was evident in college players from field and court sports. These results suggest the need for different muscle strength training and rehabilitation protocols for college players according to the musculature requirements in their respective sports. PMID:23487043

  7. H:q ratios and bilateral leg strength in college field and court sports players.

    PubMed

    Cheung, Roy T H; Smith, Andrew W; Wong, Del P

    2012-06-01

    One of the key components in sports injury prevention is the identification of imbalances in leg muscle strength. However, different leg muscle characteristics may occur in large playing area (field) sports and small playing area (court) sports, which should be considered in regular injury prevention assessment. This study examined the isokinetic hamstrings-to-quadriceps (H:Q) ratio and bilateral leg strength balance in 40 male college (age: 23.4 ± 2.5 yrs) team sport players (field sport = 23, soccer players; court sport = 17, volleyball and basketball players). Five repetitions of maximal knee concentric flexion and concentric extension were performed on an isokinetic dynamometer at two speeds (slow: 60°·s(-1) and fast: 300°·s(-1)) with 3 minutes rest between tests. Both legs were measured in counterbalanced order with the dominant leg being determined as the leg used to kick a ball. The highest concentric peak torque values (Nm) of the hamstrings and quadriceps of each leg were analyzed after body mass normalization (Nm·kg(-1)). Court sport players showed significantly weaker dominant leg hamstrings muscles at both contraction speeds (P < 0.05). The H:Q ratio was significantly larger in field players in their dominant leg at 60°·s(-1) (P < 0.001), and their non-dominant leg at 300°·s(-1) (P < 0.001) respectively. Sport-specific leg muscle strength was evident in college players from field and court sports. These results suggest the need for different muscle strength training and rehabilitation protocols for college players according to the musculature requirements in their respective sports.

  8. Body composition and muscle strength predictors of jumping performance: differences between elite female volleyball competitors and nontrained individuals.

    PubMed

    Ćopić, Nemanja; Dopsaj, Milivoj; Ivanović, Jelena; Nešić, Goran; Jarić, Slobodan

    2014-10-01

    Studies of the role of various anthropometric, physiological, and biomechanical variables in performance of rapid movements have generally revealed inconsistent findings. Within this study, we tested the hypotheses that (a) both body composition and leg extensor strength variables would reveal significant relationship with jumping performance, whereas (b) the same relationships would be stronger in physically active nonathletes than in the elite athletes proficient in vertical jumping. Top-level female volleyball players (VP; N = 35) and physically active female nonathletes (PA; N = 21) were tested on maximum vertical jumps performed with and without arm swing, as well as on body composition (percent fat and muscle) and leg press strength (maximum force and the rate of force development). The results revealed significant relationships between the jumping performance and body composition variables that appeared to be higher in PA (r = 0.65-0.76; all p < 0.01) than in VP (r = 0.37-0.42; all p ≤ 0.05). The relationships between the jumping performance and the leg strength variables were mainly significant (r = 0.23-0.68) and similar in 2 groups. We conclude that not only the leg extensor strength but also the body composition variables could be valid predictors of jumping performance and, possibly, other rapid movements. Moreover, the body composition variables that have been mainly neglected in the literature could be particularly strong predictors of performance of jumping in nonathletes, as compared with relatively homogeneous populations of elite athletes.

  9. Accountability Systems and Instructional Approaches in Youth Volleyball Training

    PubMed Central

    Pereira, Felismina; Mesquita, Isabel; Graça, Amândio

    2009-01-01

    The purpose of this study was to examine accountability systems operating in youth volleyball training sessions and to understand how those systems vary according to the instructional tasks and the nature of the information provided by coaches. Additionally, the interactive effect of the players’ age group on accountability systems and instructional tasks will be inspected. Twenty-eight youth volleyball coaches (for under 14s and under 18s) were observed, one training session each. Systematic observation strategies were used to describe and analyse task presentation and task structure during practice. Results convey that the accountability systems implemented by coaches were mainly implicit and governed by opportunity rather than explicit performance criteria imparted in task presentation. Remarks on the quality of performance only occurred during ongoing practice. More often than not coaches showed no reaction when athletes did not accomplish the tasks, failing to convey consequential expectancy-demand-monitoring messages. The instructional approach was predominantly composed of informing tasks, of technical nature and general information, which can reflect a technique and generalist coach profile. These results indicate the presence of weak and ambiguous accountability system, also corroborated by positive correlations of extending tasks with the category without exigency task presentation as well as with no reaction to unaccomplished tasks. There were no notorious differences in accountability behaviours between players’ age group. Key points Accountability systems implemented by coaches were mainly implicit and governed by opportunity rather than explicit performance criteria imparted in task presentation. Only during practice, coaches remark the performance quality, followed by participation/effort. The instructional approach was predominantly composed of informing tasks, of technical nature and general information, which can reflect a technique and

  10. Thigh muscularity and strength in teenage soccer players.

    PubMed

    Hoshikawa, Y; Iida, T; Muramatsu, M; Ii, N; Nakajima, Y; Chumank, K; Kanehisa, H

    2013-05-01

    This study examined the thigh muscularity and strength capability in early adolescent soccer players. The cross-sectional areas (CSAs) of the thigh muscles and dynamic strength during knee extension and flexion at 1.05 rad/s were determined twice at an interval of 6 months in 24 male soccer players aged 12-13 years and 11 age- and body height-matched non-athletes. After 6 months, muscle CSA and dynamic strength increased without significant interaction of time and group. Thigh total muscle CSA was not significantly affected by group, but the value relative to either thigh CSA or body mass was higher in soccer players. While knee flexion strength was similar between the 2 groups, knee extension strength was greater in soccer players than in non-athletes, even in terms of strength relative to CSA. The current results indicate that, compared with age- and body height-matched non-athletes, early adolescent soccer players are characterized by higher relative distribution of muscle mass within the thigh and higher knee extension strength relative to the quadriceps CSA. During the growth stage in which body height begins to increase markedly, however, participation in competitive soccer training does not increase the rate of development in thigh muscularity and strength.

  11. MedlinePlus: Viewers & Players

    MedlinePlus

    ... Player Play video and audio files on Apple operating systems. mov Apple iTunes Download NLM podcasts and applications. ... Player Play video and audio files on PC operating systems. mp3 wav wmz Microsoft Excel Viewer Open, view ...

  12. Teaching Beginning Trombone Players.

    ERIC Educational Resources Information Center

    Fallis, Todd L.

    2001-01-01

    Discusses the process of introducing the trombone to beginning students and addresses the issue of warming-up. Provides resources for beginning trombone methods, band methods, and daily warm-up studies. Includes resources for scale studies and etudes for beginning to intermediate trombone players. (CMK)

  13. Pre-Activity and Post-Activity Stretching Perceptions and Practices in NCAA Division I Volleyball Programs

    ERIC Educational Resources Information Center

    Judge, Lawrence W.; Bodey, Kimberly J.; Bellar, David; Bottone, Adam; Wanless, Elizabeth

    2010-01-01

    The purpose of this study was to determine if NCAA Division I women's volleyball programs were in compliance with suggested current pre- and post-activity stretching protocols. Questionnaires were sent to NCAA division I women's volleyball programs in the United States. Fifty six coaches (23 males & 33 females) participated in the study. Some…

  14. Performance indicators analysis at Brazilian and Italian women's volleyball leagues according to game location, game outcome, and set number.

    PubMed

    Campos, Fabio A D; Stanganélli, Luiz C R; Campos, Leandra C B; Pasquarelli, Bruno N; Gómez, Miguel-Angel

    2014-04-01

    This study was done to investigate the advantage of playing at home in elite women's volleyball leagues and the influence of performance indicators in the game score according to set number. The sample consisted of 240 games of the Brazilian Volleyball League (n = 132 games) and the Italian Volleyball League (n = 108 games) from the 2011-2012 season. The relationship of performance indicators (including serve, attack, block, and opponents' errors) with the game outcome (win or lose) was assessed. The results showed that there was a home advantage effect in women's volleyball leagues, with a higher prevalence of victory for the home teams in Brazilian and Italian leagues (58 and 56%, respectively). When related to the performance indicators and among the aspects that were most highly correlated with victory, the attack was the technical indicator that explained most of the results of volleyball games.

  15. Comparison of body composition and nutrients' deficiencies between Portuguese rink-hockey players.

    PubMed

    Silva, Maria-Raquel G; Silva, Hugo-Henrique

    2017-01-01

    We evaluated dietary intake and body composition of child and adolescent rink-hockey players and controls. Seventy-two male rink-hockey players (38 children and 34 adolescents) and 79 male controls (43 children and 36 adolescents) were evaluated in order to collect training data, detailed dietary intake and body composition. Rink-hockey players presented significantly lower body fat (BF) and higher fat-free mass (FFM) than controls. Mean intakes of carbohydrate and protein were considered to be adequate, but mean intakes of fat were above the recommended levels in athletes. Significant differences were found for energy intake (EI) and exercise energy expenditure (EEE) between athletes and controls (P < 0.05), resulting in some cases of low energy availability in rink-hockey players. Significant group differences (P < 0.05) were also observed for vitamins and mineral intakes in child and adolescent rink-hockey players due to higher mean intakes in control groups. Low intakes of vitamins D, E and K, calcium, iron, boron and magnesium were reported in athletes, with exception for thiamine (P = 0.449), riboflavin (P = 0.246), pantothenic acid (P = 0.065), magnesium (P = 0.061) and phosphorus (P = 0.051) in children and for niacin (P = 0.652), vitamin D (P = 0.406) and zinc (P = 0.783) in adolescents.

  16. Eating and nutrition habits in young competitive athletes: a comparison between soccer players and cyclists.

    PubMed

    Galanti, Giorgio; Stefani, Laura; Scacciati, Irene; Mascherini, Gabriele; Buti, Gabriella; Maffulli, Nicola

    2015-01-01

    The study evaluated the dietary habits in two groups of young athletes, practicing two different sports: soccer players and cycling. The dietary habits of 47 athletes were investigated by questionnaire. Body Mass Index, Fat Mass, Free Fat Mass, Total Body, Intracellular, Extracellular Water and Phase Angle were measured by bioimpedance. The t-Student test for unpaired data was used. Significance was set at P < 0.05. Body Mass Index was similar between the groups, while total body water and extracellular water were significantly higher in the soccer player group (soccer players: 63.8±1.96%; cyclists : 59.8 ± 8.7%; and soccer players 43.9±3.1%, cyclists 43.8 ±2.1%, respectively). Fatty mass of the soccer player group (14.5±2.9%) was significantly lower than that of the cyclist group (19.5±3.6%). Daily food intake was similar between the two groups (2844 kCal/die for soccer players /2630 kcal/die for cyclists), and lower than recommended. There was a low intake of Calcium (soccer players 1120±128.9 mg/die, cyclists 718±309 mg/die) for both groups, and a low intake of Potassium for soccer player (2576 mg/die ± 52.4) The caloric intake of adolescent athletes is lower than recommended. Body composition is significantly different between soccer players and cyclists.

  17. SteroMoviePlayer

    SciTech Connect

    Hodson, Steve; Pugmire, Dave

    2005-03-14

    StereoMoviePlayer StereoMoviePlayer (SMP) is a software package for creating and displaying stereo movies on a variety of computer architectures and display configuations. SMP is capable of running in serial, or in parallel to facilitate multiple computers driving a collection of display surfaces. SMP utilizes the standatd openGL gaphics library for display of both monoscopic and stereoscopic images and MPI for parallel communication and sychronization between multiple computers. SMP uses standard IO methods for loading movie files into memory and, when compressed movies are being displayed uses zLIB (which is standard in most Linux/Unix;/IRIX distributions) for decompression. A movie file is simply a concatenation of each frame. Each frame is a raw red/green/blue encoding. For stereoscopic movies, concatenation is left followed by right, as follows; Frame0-Left, Frame0-Right, Frame1-Left, Frame1-Right .... FrameN-Left, FrameN-Right To enhance performance, this concatenation of frames can be compressed using the aforementioned zLib compression/decompression library. ConvertMovie is a utility that converts between compressed and uncompressed movie formats. ConvertMovie uses zLib, which is included in most standard Linux/Unix/IRIX distributions for compression and decompression. StereoMoviePlayer consists of 3 main parts: 1-Initialization. Information is parsed from a configuration script that specifies machines on which to run, the movie file and the parameters for each graphics display. MPI is then used to instantiate a movie player on each specified computer. 2-Per-node initialization. Each parallel node creates 2 threads of execution, an IO thread and a display and communication thread. 3-Execution: The IO thread reads movie frames from disk, decompresses if necessary and places the frames in main memory. The display thread copies fromes from main memory to the graphics card for display. The display thread also handles synchronization among the other nodes

  18. A comparison of jump height, takeoff velocities, and blocking coverage in the swing and traditional volleyball blocking techniques.

    PubMed

    Ficklin, Travis; Lund, Robin; Schipper, Megan

    2014-01-01

    The purpose of this study was to compare traditional and swing blocking techniques on center of mass (COM) projectile motion and effective blocking area in nine healthy Division I female volleyball players. Two high-definition (1080 p) video cameras (60 Hz) were used to collect two-dimensional variables from two separate views. One was placed perpendicular to the plane of the net and the other was directed along the top of the net, and were used to estimate COM locations and blocking area in a plane parallel to the net and hand penetration through the plane of the net respectively. Video of both the traditional and swing techniques were digitized and kinematic variables were calculated. Paired samples t-tests indicated that the swing technique resulted in greater (p < 0.05) vertical and horizontal takeoff velocities (vy and vx), jump height (H), duration of the block (tBLOCK), blocking coverage during the block (C) as well as hand penetration above and through the net's plane (YPEN, ZPEN). The traditional technique had significantly greater approach time (tAPP). The results of this study suggest that the swing technique results in both greater jump height and effective blocking area. However, the shorter tAPP that occurs with swing is associated with longer times in the air during the block which may reduce the ability of the athlete to make adjustments to attacks designed to misdirect the defense. Key PointsSwing blocking technique has greater jump height, effective blocking area, hand penetration, horizontal and vertical takeoff velocity, and has a shorter time of approach.Despite these advantages, there may be more potential for mistiming blocks and having erratic deflections of the ball after contact when using the swing technique.Coaches should take more than simple jump height and hand penetration into account when deciding which technique to employ.

  19. Fitness Profiles of Elite Portuguese Rugby Union Players

    PubMed Central

    Vaz, Luís; Morais, Tomaz; Rocha, Henrique; James, Nic

    2014-01-01

    The aim of this study was to describe the fitness profiles of senior elite Portuguese rugby players. Forty-six senior Portuguese rugby players, classified as backs (n=22; age 26.2±2.8) and forwards (n=24; age 26.7±2.9) were assessed during physical testing sessions carried out for the Portuguese National rugby team. The body composition, maximum strength and anaerobic capacity of players are hypothesized to be important physical characteristics as successful performance in rugby is predicated on the ability to undertake skilled behaviours both quickly and whilst withstanding large forces when in contact situations. No absolute differences were found between the backs and forwards for the speed performance variables although positional differences were found across all speeds when assessed relative to body mass since the forwards were significantly heavier. Coaches and the management team can use this information for monitoring progressive improvements in the physiological capacities of rugby players. These physical characteristics of elite rugby players provide normative profiles for specific positions and should form the basis of developmental programmes for adolescents. PMID:25114750

  20. The Effect of Movement Imagery Training on Learning Forearm Pass in Volleyball

    ERIC Educational Resources Information Center

    Ay, Khitam Mousa; Halaweh, Rami Saleh; Al-Taieb, Mohammad Abu

    2013-01-01

    This study investigates the effect of movement imagery on learning the forearm pass in volleyball. Twenty four mail students from Physical Education Factuly at Jordan University (19 ± 0.5) years of age. After Completed the Movement Imagery Questionnaire-Revised (MIQ-R; Hall & Martin, 1997) the subjects randomly divided into two groups,…

  1. Exploring Changes to a Teacher's Teaching Practices and Student Learning through a Volleyball Content Knowledge Workshop

    ERIC Educational Resources Information Center

    Kim, Insook

    2016-01-01

    This paper describes how improving a teacher's content knowledge changes his teaching practices and its subsequent effects on student learning during a middle school volleyball instructional unit. The study was designed to challenge teacher educators' thinking about the importance of in-depth content knowledge for effective teaching by…

  2. No Boys Allowed on the Volleyball Team: "Clark v Arizona Interscholastic Association."

    ERIC Educational Resources Information Center

    Johnson, T. Page

    1990-01-01

    In "Clark v. Arizona Interscholastic Association (Clark II)," the Ninth Circuit Court of Appeals reaffirmed that an association rule precluding boys from playing on girls' volleyball teams does not deny the boys equal protection even though it effectively eliminates boys from interscholastic competition in high schools without separate…

  3. Comparison of Three Instructional Approaches to Enhance Tactical Knowledge in Volleyball among University Students

    ERIC Educational Resources Information Center

    Vande Broek, Gert; Boen, Filip; Claessens, Manu; Feys, Jos; Ceux, Tanja

    2011-01-01

    This study investigated the decision-making process of three instructional groups (i.e., teacher-centered, student-centered with tactical questioning and student-centered without tactical questioning) in practical courses in volleyball among university students. All students (N = 122) performed a Tactical Awareness task on the correctness of the…

  4. Effects of Classwide Peer Tutoring on the Performance of Sixth Grade Students during a Volleyball Unit

    ERIC Educational Resources Information Center

    Ayvazo, Shiri; Ward, Phillip

    2009-01-01

    This investigation examined the effects of Classwide Peer Tutoring (CWPT), a variation of peer tutoring on the volleyball skills of four 6th grade middle school students purposefully selected from an intact class of 21 students. Participants were average to low skilled males and females. A single subject A-B-A-B withdrawal design was used to…

  5. Muscle and tendon adaptation in adolescent athletes: A longitudinal study.

    PubMed

    Mersmann, F; Bohm, S; Schroll, A; Boeth, H; Duda, G N; Arampatzis, A

    2017-01-01

    There is evidence that a non-uniform adaptation of muscle and tendon in young athletes results in increased tendon stress during mid-adolescence. The present longitudinal study investigated the development of the morphological and mechanical properties of muscle and tendon of volleyball athletes in a time period of 2 years from mid-adolescence to late adolescence. Eighteen elite volleyball athletes participated in magnetic resonance imaging and ultrasound-dynamometry sessions to determine quadriceps femoris muscle strength, vastus lateralis, medialis and intermedius morphology, and patellar tendon mechanical and morphological properties in mid-adolescence (16 ± 1 years) and late adolescence (18 ± 1 years). Muscle strength, anatomical cross-sectional area (CSA), and volume showed significant (P < 0.05) but moderate increases of 13%, 6%, and 6%, respectively. The increase of patellar tendon CSA (P < 0.05) was substantially greater (27%) and went in line with increased stiffness (P < 0.05; 25%) and reduced stress (P < 0.05; 9%). During late adolescence, a pronounced hypertrophy of the patellar tendon led to a mechanical strengthening of the tendon in relation to the functional and morphological development of the muscle. These adaptive processes may compensate the unfavorable relation of muscle strength and tendon loading capacity in mid-adolescence and might have implications on athletic performance and tendon injury risk.

  6. Development of Body Composition, Hormone Profile, Physical Fitness, General Perceptual Motor Skills, Soccer Skills and On-The-Ball Performance in Soccer-Specific Laboratory Test Among Adolescent Soccer Players

    PubMed Central

    Vänttinen, Tomi; Blomqvist, Minna; Häkkinen, Keijo

    2010-01-01

    The aim of the present study was to examine the development of on-the-ball skills in soccer-specific laboratory test and to examine how traditional measures of body composition, hormone profile, physical fitness, general perceptual motor skills and soccer skills were related to performance measured in open skill environment among 10, 12, and 14-year-old regional male soccer players (n = 12/group). The measured variables were height, weight, fat, muscle mass, testosterone, 10m sprint, agility, counter movement jump, peripheral awareness, Eye- Hand-Foot coordination, passing skill, dribbling skill and on-the-ball skills (performance time and passing accuracy) in soccer-specific laboratory test. A significant main effect by age was found in all measured variables except in fat, in peripheral awareness and in passing accuracy. In discriminant analysis 63.9% (λ = 0.603, F = 4.600, p < 0.01) of the players were classified correctly based on physical fitness and general perceptual motor skills into three ability groups originally classified with performance time in soccer-specific laboratory test. Correlation co- efficient analysis with-in age groups revealed that variables associated with performance time in soccer-specific laboratory test were peripheral awareness (r = 0.72, p < 0.01) in 10-year-olds; testosterone (r = -0.70, p < 0.05), dribbling skill (r = 0.73, p < 0.01) and passing skill (r = 0.73, p < 0.01) in 12-year-olds; agility (r = 0.79, p < 0.01), counter movement jump (r = - 0.62, p < 0.01), dribbling skill (r = 0.80, p < 0.01) and passing skill (r = 0.58, p < 0. 05) in 14-year olds. Corresponding relationships with passing accuracy were weight (r = 0.59, p < 0.05), fat (r = 0.66, p < 0.05), 10m sprint (r = 0.71, p < 0.01) and countermovement jump (r = -0.64, p < 0.05) in 10-year-olds; Eye-Hand-Foot coordination (r = 0.63, p < 0.05) in 14-year- olds. The relationship between soccer-specific anticipation time and performance time in soccer- specific

  7. Communicative Competency among Poker Players.

    ERIC Educational Resources Information Center

    Hayano, David M.

    1980-01-01

    Discusses the use of specific styles of strategic interaction among professional poker players in their attempts to conceal, distort, or discover useful information about their opponents in order to maximize some gain. (JMF)

  8. Freedom between the Lines: Clothing Behavior and Identity Work among Young Female Soccer Players

    ERIC Educational Resources Information Center

    Hendley, Alexandra; Bielby, Denise D.

    2012-01-01

    Our research examines the relationship among identity, age, gender and athleticism through a study of the association between sports clothing and the identity work of pre-adolescent female soccer players. Based on participant-observation and interviews conducted at three co-ed youth soccer camps, we find that age is an important element of…

  9. Differential performance of Chinese volleyball athletes and nonathletes on a multiple-object tracking task.

    PubMed

    Zhang, Xuemin; Yan, Ming; Yangang, Liao

    2009-12-01

    The difference between athletes and nonathletes on the performance of a multiple-object tracking (MOT) task was examined. Participants were 17 national professional volleyball athletes and 20 age-matched nonathletes who were university students and attended basic volleyball training classes. Across trials, the number of distractors and the color and form of the targets were manipulated. A negative correlation was observed between the number of distractors and participants' reaction time. Further, all participants responded faster when the target color changed during a trial than when it remained consistent. Athletes had faster reaction time than nonathletes independent of the number of distractors or target manipulation. Male athletes also had faster overall reaction time than female athletes. The implications of these findings for athletic training are discussed.

  10. Online Computer Gaming: A Comparison of Adolescent and Adult Gamers

    ERIC Educational Resources Information Center

    Griffiths, M. D.; Davies, Mark N. O.; Chappell, Darren

    2004-01-01

    Despite the growing popularity of online game playing, there have been no surveys comparing adolescent and adult players. Therefore, an online questionnaire survey was used to examine various factors of online computer game players (n=540) who played the most popular online game Everquest. The survey examined basic demographic information, playing…

  11. Sleep Quality, Mood and Performance: A Study of Elite Brazilian Volleyball Athletes

    PubMed Central

    Andrade, Alexandro; Bevilacqua, Guilherme G.; Coimbra, Danilo R.; Pereira, Fabiano S.; Brandt, Ricardo

    2016-01-01

    This investigation analyzed the relationships between sleep quality, mood, and game results in the elite athletes participating in Brazilian volleyball competitions. Participants (n = 277 elite Brazilian volleyball athletes, 214 (77.3%) men and 63 (22.7%) women) completed the Brunel Mood Scale (BRUMS) and reported their subjective sleep perception. Athletes with poor sleep quality reported higher scores for confusion compared to athletes with good sleep quality (p < 0.01, d = 0.43). In addition, athletes who lost their game at the time of evaluation showed higher tension (p < 0.01, d = 0.49) and confusion (p < 0.01, d = 0.32) levels compared to athletes who won their game. A regression analysis demonstrated that for each point increase in the confusion level, there was a 19.7% reduction in sleep quality. Multivariate analysis of variance indicated that athletes who slept well, and won their games, had lower tension levels. Further, our results indicated that the athletes’ mood associated with their success in the competitions. Therefore, in a competition, it is important that the athletes show good sleep quality, and use techniques and strategies to ease their mood variations. Key points Study evaluated Self-Rated sleep quality, mood and performance of 277 elite Brazilian volleyball athletes. Our results indicated that for every pointwise increase in the level of confusion, there was an associated 19.7% reduction in sleep quality Athletes who slept well, and won their games, had lower tension levels. PMID:27928205

  12. Game-Related Performance Factors in four European Men’s Professional Volleyball Championships

    PubMed Central

    Casals, Martí

    2016-01-01

    Abstract The present study was designed to assess the relevance of game-related performance factors as outcome predictors in high-level volleyball. To carry out the analysis, the official box scores of 399 matches played by 47 different teams in four different European male professional volleyball leagues (Italy, Poland, Germany and Turkey) during the 2013-14 regular season were analyzed. A logistic mixed model was performed to determine the effects of different variables in matches’ outcomes. According to the multivariate analysis the following factors were significantly associated with winning matches: the number of scorers (OR = 1.32; CI: 1.09 – 1.59), service errors (OR = 0.91; CI: 0.87 – 0.95), service points (OR = 1.25; CI: 1.15 -1.36), reception errors (OR = 0.79; CI: 0.74 – 0.84), the percentage of positive receptions (OR = 1.02; CI: 1.00 -1.04) and blocked balls (OR = 1.17; CI: 1.11 – 1.26). Team category 2 (OR = 0.39; CI: 0.24 – 0.63) and team category 3 (OR = 0.15; CI: 0.09 – 0.25) were significantly associated with losing matches. These findings can contribute to a better understanding of performance indicators in professional volleyball, helping coaches and decision makers to better determine the importance of particular game factors. PMID:28149426

  13. Multiple Past Concussions in High School Football Players

    PubMed Central

    Brooks, Brian L.; Mannix, Rebekah; Maxwell, Bruce; Zafonte, Ross; Berkner, Paul D.; Iverson, Grant L.

    2017-01-01

    Background There is increasing concern about the possible long-term effects of multiple concussions, particularly on the developing adolescent brain. Whether the effect of multiple concussions is detectable in high school football players has not been well studied, although the public health implications are great in this population. Purpose To determine if there are measureable differences in cognitive functioning or symptom reporting in high school football players with a history of multiple concussions. Study Design Cross-sectional study; Level of evidence, 3. Methods Participants included 5232 male adolescent football players (mean [±SD] age, 15.5 ± 1.2 years) who completed baseline testing between 2009 and 2014. On the basis of injury history, athletes were grouped into 0 (n = 4183), 1 (n = 733), 2 (n = 216), 3 (n = 67), or ≥4 (n = 33) prior concussions. Cognitive functioning was measured by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery, and symptom ratings were obtained from the Post-Concussion Symptom Scale. Results There were no statistically significant differences between groups (based on the number of reported concussions) regarding cognitive functioning. Athletes with ≥3 prior concussions reported more symptoms than did athletes with 0 or 1 prior injury. In multivariate analyses, concussion history was independently related to symptom reporting but less so than developmental problems (eg, attention or learning problems) or other health problems (eg, past treatment for psychiatric problems, headaches, or migraines). Conclusion In the largest study to date, high school football players with multiple past concussions performed the same on cognitive testing as those with no prior concussions. Concussion history was one of several factors that were independently related to symptom reporting. PMID:27474382

  14. Shoulder injuries in soccer players

    PubMed Central

    Longo, Umile Giuseppe; Loppini, Mattia; Berton, Alessandra; Martinelli, Nicolò; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Summary Even though soccer is the most popular sport of the world, no review is available at present to resume the available data on shoulder injuries in soccer. The aim of this review is to report the available epidemiological data on shoulder specific injuries in soccer players and to describe the common mechanisms of shoulder injuries in soccer. Studies published through September 15, 2011, were identified by using MEDLINE, EMBASE, CINAHL and Pre-CINAHL, Pub-Med, Web of Science, and the full Cochrane Library. Reference lists of included studies were searched by hand. Studies were included if they reported on shoulder injuries in soccer players. Limits were not placed on year of publication, status of publication, or language. The journal, authors, and author affiliations of included studies were masked from 2 reviewers. We planned to perform a study on the epidemiology, mechanisms and management of shoulder injuries in elite soccer players. We also planned to use Review Manager (RevMan. Version 5 for Windows) to calculate the magnitude of treatment effect. No studies on clinical outcome of shoulder injuries in elite soccer athletes were found. No studies on the mechanism of shoulder injury in elite soccer players were found. The results of the available studies on epidemiology are reported. Despite soccer is the world’s game, few studies focused on shoulder injuries in soccer players, and therefore no definitive conclusions can be drawn. Further research is warranted to clarify the epidemiology, mechanisms and management of shoulder injuries in elite soccer players. PMID:23289025

  15. Sport injuries aligned to peak height velocity in talented pubertal soccer players.

    PubMed

    van der Sluis, A; Elferink-Gemser, M T; Coelho-e-Silva, M J; Nijboer, J A; Brink, M S; Visscher, C

    2014-04-01

    In young athletes, demands of sports are superimposed on normal growth and maturation. It has been suggested that this causes a temporarily increased vulnerability for injuries. We followed 26 talented soccer players (mean age 11.9±0.84 years) longitudinally for 3 years around their adolescent growth spurt, called Peak Height Velocity, to identify differences in number of traumatic and overuse injuries and days missed due to injuries. Peak Height Velocity was calculated according to the Maturity Offset Protocol. The number of injuries was calculated for each player per year. A repeated measurement analysis showed that athletes had significantly more traumatic injuries in the year of Peak Height Velocity (1.41) than in the year before Peak Height Velocity (0.81). A moderate effect size of 0.42 was found for the difference in number of overuse injuries per player per year before (0.81) and after Peak Height Velocity (1.41), respectively. Finally, a moderate effect size of 0.55 was found for difference between days missed due to injuries before (7.27 days per player per year) and during Peak Height Velocity (15.69 days per player per year). Adolescent growth spurt seems to result in increased vulnerability for traumatic injuries. Afterwards athletes seem to be susceptible to overuse injuries.

  16. Who Are the Players in Canadian Curriculum?

    ERIC Educational Resources Information Center

    Milburn, Geoffrey

    1987-01-01

    Labels range of persons advocating different theoretical positions of Canadian curriculum as "players." Describes players as "managers,""predictors,""transformers,""sleuths,""analysts." Values varied viewpoints for attention to language regarding curriculum, critical review of…

  17. The Effectiveness Evaluation among Different Player-Matching Mechanisms in a Multi-Player Quiz Game

    ERIC Educational Resources Information Center

    Tsai, Fu-Hsing

    2016-01-01

    This study aims to investigate whether different player-matching mechanisms in educational multi-player online games (MOGs) can affect students' learning performance, enjoyment perception and gaming behaviors. Based on the multi-player quiz game, TRIS-Q, developed by Tsai, Tsai and Lin (2015) using a free player-matching (FPM) mechanism, the same…

  18. [Hemodynamic Status of Prepubertal and Pubertal Hockey Players].

    PubMed

    Shayhelislamova, M V; Sitdikov, F G; Zefirov, T L; Dikopolskaya, N B

    2015-01-01

    The hemodynamic status of 11-15-year-old hockey players depending on their age and puberty stage were studied and compared with hemodynamic parameters of the control group. It was found that regular muscle training has a dominant effect on the functional state of cardiovascular system (CVS) in prepuberty and puberty. It was proved that in hockey players a decrease in the heart rate (H R) and an increase in the stroke volume (SV) result in a significant increase in systolic blood pressure (SBP) at the age of 11-14 years and a progressive increase in total peripheral vascular resistance (PVR), in contrast to significantly lower values in the control group. The urgent adaptation of CVS to graduated physical activities at the age of 11-13 years leads to an enhancement of vascular spasmodic reactions while SV remains constant. It was found that in adolescent hockey players have consistently high SV and SBP; at the same time, maximal values of HR, cardiac output (CO) and diastolic blood pressure (DBP) were observed at the stages I and II of the puberty period; then, at the stage III, these parameters decrease. I n the control group, hymodinamic status changed in an opposite way. This may be an evidence of the stress effect of physical activities which results in the adaptive reactions of CVS rather than reactions typical of the puberty period.

  19. Spondylolysis in young tennis players

    PubMed Central

    Ruiz‐Cotorro, A; Balius‐Matas, R; Estruch‐Massana, A; Angulo, J Vilaró

    2006-01-01

    The general aetiology, diagnosis, and treatment of spondylolysis, a bone defect in the pars interarticularis of the vertebra, are reviewed. A retrospective study of young tennis players diagnosed between 2000 and 2004 with spondylolysis with or without spondylolisthesis, assessed by radiography and planar bone scintigraphy, is described. If the radiographic results were negative, computed tomography was performed. Sixty six cases were evaluated: 53 L5 lesions, eight L4 lesions, two L3 lesions, and one bilateral lesion at the L2 level. Two more lesions at two levels were found (bilateral L5 and unilateral L4 and L3 on the right side). Classification, treatment, and outcome of the cases are reported. A combination of radiography, planar bone scintigraphy, and SPECT is useful for evaluating spondylolysis in tennis players and recommending treatment. Use of a brace did not appear to achieve significant results. PMID:16632576

  20. [Feet dermatophytosis in soccer players].

    PubMed

    Purim, Kátia Sheylla Malta; de Freitas, Camila Fernanda Novak Pinheiro; Leite, Neiva

    2009-01-01

    Athletes present risk of cutaneous mycosis. A study was carried out with 23 soccer players using clinical and mycological examination (direct microscopic examination and culture) and nail clipping. Eighteen (78.26%) did not present mycosis; two (8.70%) presented tinea pedis, and three (13.04%) presented onychomycosis associated to tinea pedis, mainly for Trichophyton mentagrophytes. Infected tinea pedis has produced cellulitis in one of the athletes. It is necessary to create an educative program of skin care during sports practice.

  1. Proficiency Assessment of Male Volleyball Teams of the 13-15-Year Age Group at Estonian Championships

    ERIC Educational Resources Information Center

    Stamm, Meelis; Stamm, Raini; Koskel, Sade

    2008-01-01

    Study aim: Assessment of feasibility of using own computer software "Game" at competitions. Material and methods: The data were collected during Estonian championships in 2006 for male volleyball teams of the 13-15-years age group (n = 8). In all games, the performance of both teams was recorded in parallel with two computers. A total of…

  2. Two-Player Graph Pebbling

    NASA Astrophysics Data System (ADS)

    Prudente, Matthew James

    Given a graph G with pebbles on the vertices, we define a pebbling move as removing two pebbles from a vertex u, placing one pebble on a neighbor v, and discarding the other pebble, like a toll. The pebbling number pi( G) is the least number of pebbles needed so that every arrangement of pi(G) pebbles can place a pebble on any vertex through a sequence of pebbling moves. We introduce a new variation on graph pebbling called two-player pebbling. In this, players called the mover and the defender alternate moves, with the stipulation that the defender cannot reverse the previous move. The mover wins only if they can place a pebble on a specified vertex and the defender wins if the mover cannot. We define η(G), analogously, as the minimum number of pebbles such that given every configuration of the η( G) pebbles and every specified vertex r, the mover has a winning strategy. First, we will investigate upper bounds for η( G) on various classes of graphs and find a certain structure for which the defender has a winning strategy, no matter how many pebbles are in a configuration. Then, we characterize winning configurations for both players on a special class of diameter 2 graphs. Finally, we show winning configurations for the mover on paths using a recursive argument.

  3. Patellar tendon morphology in volleyball athletes with and without patellar tendinopathy.

    PubMed

    Kulig, K; Landel, R; Chang, Y-J; Hannanvash, N; Reischl, S F; Song, P; Bashford, G R

    2013-03-01

    Appropriate management of patellar tendinopathy requires distinguishing between inflammatory and degenerative conditions, often difficult because tendon thickening can be a normal or pathological adaptation, and micromorphology is not observable on clinical imaging. The purpose of this study was to quantitatively examine patellar tendon micro- and macromorphology in volleyball athletes and relate those findings to reported symptoms. Longitudinal ultrasound images of proximal and distal patellar tendons were acquired from 84 male elite volleyball athletes (44 symptomatic, 40 asymptomatic) and 10 asymptomatic nonathlete controls. Micromorphology was determined using two-dimensional Fast Fourier Transform analysis providing a discriminating peak spatial frequency parameter (PSF). Macromorphology (patellar tendon thickness) was measured using Image J software. All athletes regardless of symptoms had thicker proximal tendons compared to nonathletes, suggesting a normal adaptation to training loads. However, symptomatic athletes demonstrated lower PSF than asymptomatic athletes and nonathletes at the proximal tendon, suggesting greater collagen disorganization, and tendon degeneration rather than inflammation. Only symptomatic athletes had thicker distal tendons than nonathletes, but there was no difference in PSF distally. Diagnostic ultrasound enhances the understanding of the micromorphology of patellar tendons, supporting the rationale for management that remodels the degenerated tendon instead of treating inflammation.

  4. Identification of types of landings after blocking in volleyball associated with risk of ACL injury.

    PubMed

    Zahradnik, David; Jandacka, Daniel; Farana, Roman; Uchytil, Jaroslav; Hamill, Joseph

    2017-03-01

    Landing with a low knee flexion angle after volleyball block jumps may be associated with an increased risk of anterior cruciate ligament (ACL) injury. The aim of the present study was to identify the types of volleyball landings after blocks where the knee flexion angle is found to be under a critical knee flexion angle value of 30° at the instant of the first peak of the ground reaction force (GRF). Synchronized kinematic and kinetic data were collected for each trial. T-tests were used to determine if each knee flexion angle at the instant of the peak GRF was significantly different from the critical value of 30°. A repeated measures ANOVA was used to compare knee flexion angle, time to first peak and the magnitude of the first peak of the resultant GRF and knee stiffness. Significantly lower knee flexion angles were found in the "go" landing (p = .01, ES = 0.6) and the "reverse" landing (p = .02, ES = 0.6) only. The results for knee flexion angle and GRF parameters indicated a significant difference between a "reverse" and "go" and other types of landings, except the "side stick" landing for GRF. The "reverse" and "go" landings may present a risk for ACL injury due to the single-leg landing of these activities that have an associated mediolateral movement.

  5. Adolescent development

    MedlinePlus

    Development - adolescent; Growth and development - adolescent ... During adolescence, children develop the ability to: Understand abstract ideas. These include grasping higher math concepts, and developing moral ...

  6. 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

  7. Vitamin D Deficiency Among Professional Basketball Players

    PubMed Central

    Fishman, Matthew P.; Lombardo, Stephen J.; Kharrazi, F. Daniel

    2016-01-01

    Background: Vitamin D plays an important role in several systems of the human body. Various studies have linked vitamin D deficiency to stress and insufficiency fractures, muscle recovery and function, and athletic performance. The prevalence of vitamin D deficiency in the elite athletic population has not been extensively studied, and very few reports exist among professional athletes. Hypothesis: There is a high prevalence of vitamin D deficiency or insufficiency among players attending the National Basketball Association (NBA) Combine. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This is a retrospective review of data previously collected as part of the routine medical evaluation of players in the NBA Combines from 2009 through 2013. Player parameters evaluated were height, weight, body mass index (BMI), and vitamin D level. Statistical analysis using t tests and analysis of variance was used to detect any correlation between the player parameters and vitamin D level. Vitamin D levels were categorized as deficient (<20 ng/mL), insufficient (20-32 ng/mL), and sufficient (>32 ng/mL). Results: After institutional review board approval was submitted to the NBA, the NBA released deidentified data on 279 players who participated in the combines from 2009 through 2013. There were 90 players (32.3%) who were deficient, 131 players (47.0%) who were insufficient, and 58 players (20.8%) who were sufficient. A total of 221 players (79.3%) were either vitamin D deficient or insufficient. Among all players included, the average vitamin D level was 25.6 ± 10.2 ng/mL. Among the players who were deficient, insufficient, and sufficient, the average vitamin D levels were 16.1 ± 2.1 ng/mL, 25.0 ± 3.4 ng/mL, and 41.6 ± 8.6 ng/mL, respectively. Player height and weight were significantly increased in vitamin D–sufficient players compared with players who were not sufficient (P = .0008 and .009, respectively). Player age and BMI did not significantly

  8. 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…

  9. Adolescent Images of Adolescence.

    ERIC Educational Resources Information Center

    Falchikov, Nancy

    1989-01-01

    Examined extent to which Scottish adolescents (N=40) were influenced by negative images of adolescence present in the culture, investigating self-images by means of Q sort. Eleven factors emerged from analysis, six of which met criterion that distinguishes common factors. Little evidence was found to suggest that adolescents were influenced by…

  10. Anthropometric Characteristics of Columbia, South Carolina, Youth Baseball Players and Dixie Youth World Series Players

    ERIC Educational Resources Information Center

    French, Karen E.; Spurgeon, John H.; Nevett, Michael E.

    2007-01-01

    The purpose of this study was to compare measures of body size in two samples of youth baseball players with normative data from the United States National Center for Health Statistics (NCHS) growth charts. One sample of youth baseball players participated in a local little league. The second sample of youth baseball players were members of eight…

  11. Interaction with the game and motivation among players of massively multiplayer online role-playing games.

    PubMed

    Fuster, Héctor; Carbonell, Xavier; Chamarro, Andrés; Oberst, Ursula

    2013-01-01

    Knowledge about users interacting with Massively Multiplayer Online Role-Playing Games (MMORPG) is fundamental in order to prevent their potential negative effects on behavior. For this reason, the present study analyzed the relationship between styles of play and motivations. An online questionnaire asking for socio-demographic details, playing style, characteristics of the game played and motivations for playing, was answered by 430 Spanish-speaking MMORPG players (45.1% males). The identified profile for players, far away from the stereotype of an adolescent, consisted in a person who mainly plays on PvP (Player versus Player) servers, choosing the type of game according to his experience. Regarding motivations, they were interested in relating with other players through the game (Socialization), in discovering the game's possibilities and development of its adventures (Exploration), to a lesser extent in leadership and prestige (Achievement) and, lastly, identification with an avatar and escape from reality (Dissociation). Although part of the reason for playing was escapism and/or stress relief, the main motivation had a social nature. We conclude that MMORPG offer an attractive environment for a broad spectrum of people, and we have not been able to confirm the stereotype of a loner avoiding reality, taking refuge in games.

  12. Importance of peak height velocity timing in terms of injuries in talented soccer players.

    PubMed

    van der Sluis, A; Elferink-Gemser, M T; Brink, M S; Visscher, C

    2015-04-01

    The purpose of this study was to identify differences in traumatic and overuse injury incidence between talented soccer players who differ in the timing of their adolescent growth spurt. 26 soccer players (mean age 11.9 ± 0.84 years) were followed longitudinally for 3 years around Peak Height Velocity, calculated according to the Maturity Offset Protocol. The group was divided into an earlier and later maturing group by median split. Injuries were registered following the FIFA consensus statement. Mann-Whitney tests showed that later maturing players had a significantly higher overuse injury incidence than their earlier maturing counterparts both in the year before Peak Height Velocity (3.53 vs.0.49 overuse injuries/1 000 h of exposure,U = 49.50, z = − 2.049, p < 0.05) and the year of Peak Height Velocity (3.97 vs. 1.56 overuse injuries/1 000 h of exposure, U = 50.5, z = − 1.796,p < 0.05). Trainers and coaches should be careful with the training and match load they put on talented soccer players, especially those physically not (yet) able to handle that load. Players appear to be especially susceptible to injury between 13.5 and 14.5 years of age. Training and match load should be structured relative to maturity such that athletic development is maximized and the risk of injury is minimized.

  13. Generic anthropometric and performance characteristics among elite adolescent boys in nine different sports.

    PubMed

    Pion, Johan; Segers, Veerle; Fransen, Job; Debuyck, Gijs; Deprez, Dieter; Haerens, Leen; Vaeyens, Roel; Philippaerts, Renaat; Lenoir, Matthieu

    2015-01-01

    The aim of the present study was to evaluate the Flemish Sports Compass (FSC), a non-sport-specific generic testing battery. It was hypothesised that a set of 22 tests would have sufficient discriminant power to allocate athletes to their own sport based on a unique combination of test scores. First, discriminant analyses were applied to the 22 tests of anthropometry, physical fitness and motor coordination in 141 boys under age 18 (16.1 ± 0.8 years) and post age at peak height velocity (maturity offset = 2.674 ± 0.926) from Flemish Top Sport Academies for badminton, basketball, gymnastics, handball, judo, soccer, table tennis, triathlon and volleyball. Second, nine sequential discriminant analyses were used to assess the ability of a set of relevant performance characteristics classifying participants and non-participants for the respective sports. Discriminant analyses resulted in a 96.4% correct classification of all participants for the nine different sports. When focusing on relevant performance characteristics, 80.1% to 97.2% of the total test sample was classified correctly within their respective disciplines. The discriminating characteristics were briefly the following: flexibility in gymnastics, explosive lower-limb strength in badminton and volleyball, speed and agility in badminton, judo, soccer and volleyball, upper-body strength in badminton, basketball and gymnastics, cardiorespiratory endurance in triathletes, dribbling skills in handball, basketball and soccer and overhead-throwing skills in badminton and volleyball. The generic talent characteristics of the FSC enable the distinction of adolescent boys according to their particular sport. Implications for talent programmes are discussed.

  14. [Almaty club "KAIRAT" young football players' health].

    PubMed

    Kausova, G K; Karabaeva, A I

    2013-10-01

    The aim of the investigation was to study young football players' health. The study was conducted on 161 football players (mean age 12.3) of six children football teams of Almaty club "KAIRAT" during the competition period. It was found that 55,5% of the football players are practically healthy; 18,6% of football players have iron deficiency anemia. 32,6% of football players have caries; 5% of football players have problems of cardiopulmonary system. Investigation reveal, that in a junior sportsman was body weigh surging with downtrend during contest, testify to portability of aerobic load and in childhood unconformable of metabolism' level. This tendency was retain also in the oldest sportsman, this testify to most emulative aerobic load in comparison with junior sportsman. According as the age increases it is emulative load's extension and free occurrence of body weigh subsequent reduction but in the oldest sportsman with prevalence macrosomia. Concurrently with improvement of the anthropometric profile as far as increase of age in soccer players it is forming of a high training level. In spite of lowering of energy resources and the physical load organism's adaptation there are these phenomena. According as the age increases in a soccer player's performance of cardiac and respiratory system are improved.

  15. N-player stochastic differential games

    NASA Technical Reports Server (NTRS)

    Varaiya, P.

    1976-01-01

    The paper presents conditions which guarantee that the control strategies adopted by N players constitute an efficient solution, an equilibrium, or a core solution. The system dynamics are described by an Ito equation, and all players have perfect information. When the set of instantaneous joint costs and velocity vectors is convex, the conditions are necessary.

  16. Quantum Two Player Game in Thermal Environment

    PubMed Central

    Dajka, Jerzy; Kłoda, Dawid; Łobejko, Marcin; Sładkowski, Jan

    2015-01-01

    A two-player quantum game is considered in the presence of thermal decoherence. It is shown how the thermal environment modeled in terms of rigorous Davies approach affects payoffs of the players. The conditions for either beneficial or pernicious effect of decoherence are identified. The general considerations are exemplified by the quantum version of Prisoner Dilemma. PMID:26322833

  17. Attack Coverage in High-Level Men’s Volleyball: Organization on the Edge of Chaos?

    PubMed Central

    Laporta, Lorenzo; Nikolaidis, Pantelis; Thomas, Luke; Afonso, José

    2015-01-01

    Change is pervasive, but emerging patterns are occasionally detectable through analysis of systemic behaviors. Match analysis uses these patterns in order to reduce the degree of improvisation and to optimize the training process. However, it is possible that certain game phases elude systematic patterning. In this vein, our aim was to analyze the case of attack coverage in men’s volleyball, as we suspected it would elude systematic patterning and has received negligible attention in scientific research. We analyzed the occurrence of attack coverage in 4544 plays of the 2011 Volleyball World League. A Chi-square test with residual adjusted values was applied to explore significant associations between variables. A Monte Carlo correction was applied, as some cells had n<5. Effect sizes were determined using Cramer’s V. Overall, attack coverage occurred in 3.89% of ball possessions, and 23 distinct structures emerged. These structures lacked significant associations with the game complex, setting zone, and effect of attack coverage. Conversely, attack coverage structures showed significant associations with the attack zone and tempo, with very strong effect sizes (V=0.472 and V=0.521, respectively). As certain attack zones are deeply associated with attack tempo, it is apparent that quicker attack plays affect attack coverage structuring, promoting the formation of less complex structures. Ultimately, attack coverage structures seem to depend on momentary constraints, thereby rendering rigid systematization impracticable. Still, we contended that a principle-based approach might be suitable. This invites researchers to rethink how to interpret game regularities. PMID:26557208

  18. Executive functioning in highly talented soccer players.

    PubMed

    Verburgh, Lot; Scherder, Erik J A; van Lange, Paul A M; Oosterlaan, Jaap

    2014-01-01

    Executive functions might be important for successful performance in sports, particularly in team sports requiring quick anticipation and adaptation to continuously changing situations in the field. The executive functions motor inhibition, attention and visuospatial working memory were examined in highly talented soccer players. Eighty-four highly talented youth soccer players (mean age 11.9), and forty-two age-matched amateur soccer players (mean age 11.8) in the age range 8 to 16 years performed a Stop Signal task (motor inhibition), the Attention Network Test (alerting, orienting, and executive attention) and a visuospatial working memory task. The highly talented soccer players followed the talent development program of the youth academy of a professional soccer club and played at the highest national soccer competition for their age. The amateur soccer players played at a regular soccer club in the same geographical region as the highly talented soccer players and play in a regular regional soccer competition. Group differences were tested using analyses of variance. The highly talented group showed superior motor inhibition as measured by stop signal reaction time (SSRT) on the Stop Signal task and a larger alerting effect on the Attention Network Test, indicating an enhanced ability to attain and maintain an alert state. No group differences were found for orienting and executive attention and visuospatial working memory. A logistic regression model with group (highly talented or amateur) as dependent variable and executive function measures that significantly distinguished between groups as predictors showed that these measures differentiated highly talented soccer players from amateur soccer players with 89% accuracy. Highly talented youth soccer players outperform youth amateur players on suppressing ongoing motor responses and on the ability to attain and maintain an alert state; both may be essential for success in soccer.

  19. Executive Functioning in Highly Talented Soccer Players

    PubMed Central

    Verburgh, Lot; Scherder, Erik J. A.; van Lange, Paul A.M.; Oosterlaan, Jaap

    2014-01-01

    Executive functions might be important for successful performance in sports, particularly in team sports requiring quick anticipation and adaptation to continuously changing situations in the field. The executive functions motor inhibition, attention and visuospatial working memory were examined in highly talented soccer players. Eighty-four highly talented youth soccer players (mean age 11.9), and forty-two age-matched amateur soccer players (mean age 11.8) in the age range 8 to 16 years performed a Stop Signal task (motor inhibition), the Attention Network Test (alerting, orienting, and executive attention) and a visuospatial working memory task. The highly talented soccer players followed the talent development program of the youth academy of a professional soccer club and played at the highest national soccer competition for their age. The amateur soccer players played at a regular soccer club in the same geographical region as the highly talented soccer players and play in a regular regional soccer competition. Group differences were tested using analyses of variance. The highly talented group showed superior motor inhibition as measured by stop signal reaction time (SSRT) on the Stop Signal task and a larger alerting effect on the Attention Network Test, indicating an enhanced ability to attain and maintain an alert state. No group differences were found for orienting and executive attention and visuospatial working memory. A logistic regression model with group (highly talented or amateur) as dependent variable and executive function measures that significantly distinguished between groups as predictors showed that these measures differentiated highly talented soccer players from amateur soccer players with 89% accuracy. Highly talented youth soccer players outperform youth amateur players on suppressing ongoing motor responses and on the ability to attain and maintain an alert state; both may be essential for success in soccer. PMID:24632735

  20. Validity of the V-cut Test for Young Basketball Players.

    PubMed

    Gonzalo-Skok, O; Tous-Fajardo, J; Suarez-Arrones, L; Arjol-Serrano, J L; Casajús, J A; Mendez-Villanueva, A

    2015-11-01

    The aim of the present study was to assess the reliability, usefulness, validity, age-related differences and responsiveness of a 25- m side-step cutting maneuver test (V-cut test). Fifty young male basketball players performed the V-cut test on 2 occasions separated by 5-7 days to assess test-retest reliability and determine a priori usefulness. Twenty subjects also completed both the L-Run and 505 test to analyze the possible relationships among these 3 tests. Furthermore, 33 players performed the V-cut test 4 times throughout the season to analyze responsiveness. Finally, 53 players (U-14 to U-20) were assessed in the V-cut test to examine the age-related differences. Reliability scores showed high intraclass correlation coefficient (ICC=0.90) and low coefficient of variation (CV=1.4%). The responsiveness of the V-cut test was good, as the typical short- (1.5-1.7%), mid- (1.6-3.1%) and long-term (3.3%) changes in V-cut performance were higher than the CV. Low (r=0.64; CL90%: 0.34; 0.82) to moderate (r=0.76; CL90%: 0.53; 0.88) relationships were found between the V-cut test with the 505 and L-Run test, respectively. Age-related differences analysis showed better V-cut test performance as age increased in adolescent basketball players. The V-cut test is reliable to assess change of direction ability (CODA) and it could be used to monitor CODA in adolescent basketball players.

  1. Vascular Endothelial Growth Factor Receptor-2 Polymorphisms Have Protective Effect against the Development of Tendinopathy in Volleyball Athletes

    PubMed Central

    Salles, José Inácio; Duarte, Maria Eugenia Leite; Guimarães, João Matheus; Lopes, Lucas Rafael; Vilarinho Cardoso, Jessica; Aguiar, Diego Pinheiro; Machado Neto, João Olyntho; Machado, Daniel Escorsim; Perini, Jamila Alessandra

    2016-01-01

    The aim of the study was to investigate whether genetic variants in VEGF and KDR genes can be correlated with susceptibility of tendinopathy in volleyball athletes. This study was conducted at the Brazilian Volleyball Federation, and comprised 179 volleyball athletes: 88 had a confirmed diagnosis of tendinopathy (cases), whereas 91 had no evidence of the disease (controls). The VEGF (-2578C>A, -460T>C and +936C>T) and KDR (-604C>T, 1192G>A and 1719T>A) polymorphisms were determined by TaqMan real-time polymerase chain reaction. The odds ratio (OR) with their 95% confidence intervals (CI) were calculated using an unconditional logistic regression model. The evaluation of demographic and clinical characteristics revealed the athlete age (P < 0.001), years of practice in volleyball (P < 0.001) and presence of pain (P = 0.001) were risk factors for tendinopathy. KDR 1192 GA and GA + AA genotypes were associated with lower risk of tendinopathy (OR: 0.41, 95% CI: 0.19–0.88 and OR: 0.47, 95% CI: 0.23–0.98, respectively). The KDR (-604C>T, 1192G>A and 1719T>A) haplotypes CGA and CAT were associated with decreased tendinopathy risk (OR: 0.46, 95% CI: 0.21–0.99 and OR: 0.23, 95% CI: 0.07–0.76, respectively). With regards to pain, traumatic lesion and away from training due to injury, VEGF and KDR polymorphisms were not associated with clinical symptoms complaints. The present results provide evidence that the KDR polymorphisms were associated with development of tendinopathy, and can contribute to identify new therapeutic targets or personalized training programs to avoid tendinopathy development in athletes. PMID:27930691

  2. Vascular Endothelial Growth Factor Receptor-2 Polymorphisms Have Protective Effect against the Development of Tendinopathy in Volleyball Athletes.

    PubMed

    Salles, José Inácio; Duarte, Maria Eugenia Leite; Guimarães, João Matheus; Lopes, Lucas Rafael; Vilarinho Cardoso, Jessica; Aguiar, Diego Pinheiro; Machado Neto, João Olyntho; Machado, Daniel Escorsim; Perini, Jamila Alessandra

    2016-01-01

    The aim of the study was to investigate whether genetic variants in VEGF and KDR genes can be correlated with susceptibility of tendinopathy in volleyball athletes. This study was conducted at the Brazilian Volleyball Federation, and comprised 179 volleyball athletes: 88 had a confirmed diagnosis of tendinopathy (cases), whereas 91 had no evidence of the disease (controls). The VEGF (-2578C>A, -460T>C and +936C>T) and KDR (-604C>T, 1192G>A and 1719T>A) polymorphisms were determined by TaqMan real-time polymerase chain reaction. The odds ratio (OR) with their 95% confidence intervals (CI) were calculated using an unconditional logistic regression model. The evaluation of demographic and clinical characteristics revealed the athlete age (P < 0.001), years of practice in volleyball (P < 0.001) and presence of pain (P = 0.001) were risk factors for tendinopathy. KDR 1192 GA and GA + AA genotypes were associated with lower risk of tendinopathy (OR: 0.41, 95% CI: 0.19-0.88 and OR: 0.47, 95% CI: 0.23-0.98, respectively). The KDR (-604C>T, 1192G>A and 1719T>A) haplotypes CGA and CAT were associated with decreased tendinopathy risk (OR: 0.46, 95% CI: 0.21-0.99 and OR: 0.23, 95% CI: 0.07-0.76, respectively). With regards to pain, traumatic lesion and away from training due to injury, VEGF and KDR polymorphisms were not associated with clinical symptoms complaints. The present results provide evidence that the KDR polymorphisms were associated with development of tendinopathy, and can contribute to identify new therapeutic targets or personalized training programs to avoid tendinopathy development in athletes.

  3. Body build classification for ordinary schoolgirls (aged 7-18 years) and volleyball girls (aged 13-16 years).

    PubMed

    Kaarma, Helje; Stamm, Raini; Kasmel, Jaan; Koskel, Slide

    2005-03-01

    The article describes two Estonian anthropometric cross-sectional studies of 1549 ordinary schoolgirls (aged 7-18) and 46 girls, who regularly practised volleyball (aged 13-16). Data are presented on 22 basic anthropometric measurements and 6 body composition characteristics (body mass index, mean skinfold, body density, relative mass of fat by Siri, absolute mass and relative mass of subcutaneous adipose tissue). All anthropometric variables were classified into five height-weight SD classes. Schoolgirls were divided into six age groups (7-8, 9-10, 11-12, 13-14, 15-16, 17-18). Volleyballers were observed as one group as their age in SD classes did not differ significantly. The classification consisted of five categories: three height-weight concordant categories: I--small (small height, small weight), II--medium (medium height, medium weight), III large--(big height, big weight) and two height/weight discordant categories: IV--so-called pyknomorphs, V--so-called leptomorphs. To assess the differences between classes the Scheffé-test was used (alpha = 0.05). It proved likewise possible to comparatively systematize length, breadth and depth measurements, circumferences and body composition characteristics in all six age groups (7-18 years) of ordinary schoolgirls and in 13-16-year-old volleyballers as in their case the average age did not differ significantly between the classes.

  4. Flexibility of internal and external glenohumeral rotation of junior female tennis players and its correlation with performance ranking

    PubMed Central

    Chiang, Ching-Cheng; Hsu, Chih-Chia; Chiang, Jinn-Yen; Chang, Weng-Cheng; Tsai, Jong-Chang

    2016-01-01

    [Purpose] The purpose of this study was to compare the internal and external rotation of the dominant and nondominant shoulders of adolescent female tennis players. The correlation between the shoulder rotation range of motion and the player’s ranking was also analyzed. [Subjects and Methods] Twenty-one female junior tennis players who were 13 to 18 years old participated in this study. A standard goniometer was used to measure the internal and external rotation of both glenohumeral joints. The difference in internal and external rotation was calculated as the glenohumeral rotation deficit. The year-end ranking of each player was obtained from the Chinese Taipei Tennis Association. [Results] The internal rotation of the dominant shoulder was significantly smaller than that of the nondominant shoulder. Moreover, player ranking was significantly and negatively correlated with the internal rotation range of motion of both shoulders. On the other hand, the correlations of the internal and external rotation ranges of motion with the age, height, and weight were not significant. [Conclusion] The flexibility of the glenohumeral internal rotation is smaller in the dominant shoulder than of the nondominant shoulder in these junior female tennis players. Flexibility of the glenohumeral internal rotation may be a factor affecting performance in junior female tennis players. PMID:28174438

  5. The Presence of Bilateral Imbalance of the Lower Limbs in Elite Youth Soccer Players of Different Ages.

    PubMed

    Atkins, Stephen J; Bentley, Ian; Hurst, Howard T; Sinclair, Jonathan K; Hesketh, Christopher

    2016-04-01

    The aim of this study was to examine bilateral differences in ground reaction forces (GRF), measured during a deep squat (DS) exercise, in a population of elite youth soccer players. Bilateral muscle balance is a key component in promoting musculoskeletal health of performers, yet there is a limited evidence base investigating such imbalances in youth. Seventy-four subjects were assigned to performance groups according to chronological age (younger than 13, 14, 15, 16, 17 years). Analysis of physical maturity status revealed that very few players were classified as "early" or "late" maturers. Players completed an overhead DS exercise, as part of preseason functional movement screening. Peak GRF were assessed using a twin force plate system. Significant differences (p ≤ 0.05) were identified between right and left side peak GRF for all groups except the youngest (U13) and oldest (U17). Nondominant "sides" showed the highest levels of PGRF across all groups. The magnitude of PGRF was not significantly different both within and between groups, except for the left side in the U13 to U15 groups (p = 0.04). Results from this study show that performance asymmetry is marked in adolescence. There seems a "trigger point" during the early stage of adolescence, when bilateral imbalances become marked. These differences do seem to reduce during the later stages of adolescence. Correct attention to focussed training, designed to remediate any imbalance, is warranted in adolescent groups. This is important with respect of the key associations between bilateral asymmetry and risk of injury.

  6. Using cognitive dissonance to induce adolescents' escaping from the claw of online gaming: the roles of personal responsibility and justification of cost.

    PubMed

    Chiou, Wen-Bin; Wan, Chin-Sheng

    2007-10-01

    The negative impact of the Internet on adolescents has received much attention. How to reduce their pathological use of online gaming is also a critical issue. Based on cognitive dissonance theory, two experiments were conducted to examine whether personal responsibility and justification of cost may play crucial factors in impacting adolescent players' attitude change and their willingness to engage in attitude-discrepant behavior. The results of Experiment 1 revealed that adolescent players who felt a strong sense of responsibility appeared to exhibit greater attitude change. In Experiment 2, the findings indicated that players tended to employ justification of cost in order to reduce or eliminate the dissonance between their attitude toward online gaming and invested cost. Adolescent players who perceived a higher cost in online gaming were less willing to engage in attitude-discrepant behavior. Reducing adolescents ' overuse of online gaming can be appreciated through the perspective of cognitive dissonance.

  7. Anthropometric and Somatotype Characteristics of Young Soccer Players: Differences Among Categories, Subcategories, and Playing Position.

    PubMed

    Perroni, Fabrizio; Vetrano, Mario; Camolese, Giancarlo; Guidetti, Laura; Baldari, Carlo

    2015-08-01

    Considering that anthropometric parameters are important factors in the performance of the soccer players, the aim of this study was to explore the differences in anthropometric and somatotype characteristics of Italian young soccer players. Weight, height, body mass index, and somatotype of 112 young soccer players, grouped in Giovanissimi "A" (14 years), "B" (13 years), and "C" (12 years) as well as Allievi "B" (15 years) and "A" (16 years) and "Juniores" (older than 17 years), were evaluated. Statistical analysis tests were computed at p ≤ 0.05, and an analysis of variance for each somatotype was calculated to analyze the main effects and interactions of the factors: categories, subcategories, and playing position. Bonferroni's post hoc analysis was used to identify differences among mean values. Considering all subjects, we have found significant differences in categories, subcategories, and playing position between anthropometric values and a somatotype value of 2.8-3.8-2.9. Significant differences have found among goalkeepers and the others playing position in endomorphy (p ≤ 0.001) and with defenders and midfielders in ectomorphy (p < 0.01) components, whereas no differences in mesomorphy. Analyzing the interaction between subcategories and playing position factors, a significant effect was found only in the endomorphy component (p = 0.05). The analysis of anthropometric characteristic of Italian young soccer players indicates that players have high muscularity value and low adiposity. This study showed the presence of somatotype differences for playing position within categories also in the youngest categories and subcategories, in particular, in the endomorphy component. Young soccer players should be trained with more appropriate and specific training load to avoid the increased injury risk during adolescence.

  8. The Effects of Individualized Resistance Strength Programs on Knee Muscular Imbalances in Junior Elite Soccer Players.

    PubMed

    Śliwowski, Robert; Jadczak, Łukasz; Hejna, Rafał; Wieczorek, Andrzej

    2015-01-01

    The purpose of this study was to investigate the effects of a resistance training program on the muscular strength of soccer players' knees that initially presented unilateral and bilateral differences. For this study, a team of 24 male well-trained junior soccer players was divided into two strength program training groups: a Resistance Training Control Group (RTCG) composed of 10 players that did not have muscular imbalances and a Resistance Training Experimental Group (RTEG) composed of 14 players that had muscular imbalances. All players followed a resistance training program for six weeks, two times per week, during the transition period. The program of individualized strength training consisted of two parts. The first part, which was identical in terms of the choice of training loads, was intended for both training groups and contained two series of exercises including upper and lower body exercises. The second part of the program was intended only for RTEG and consisted of two additional series for the groups of muscles that had identified unilateral and bilateral differences. The applied program showed various directions in the isokinetic profile of changes. In the case of RTCG, the adaptations related mainly to the quadriceps muscle (the peak torque (PT) change for the dominant leg was statistically significant (p < 0.05)). There were statistically significant changes in RTEG (p < 0.05) related to PT for the hamstrings in both legs, which in turn resulted in an increase in the conventional hamstring/quadriceps ratio (H/Q). It is interesting that the statistically significant (p < 0.05) changes were noted only for the dominant leg. No statistically significant changes in bilateral differences (BD) were noted in either group. These results indicate that individualized resistance training programs could provide additional benefits to traditional strength training protocols to improve muscular imbalances in post-adolescent soccer players.

  9. Longitudinal Development of Explosive Leg Power from Childhood to Adulthood in Soccer Players.

    PubMed

    Deprez, D; Valente-Dos-Santos, J; Coelho-E-Silva, M J; Lenoir, M; Philippaerts, R; Vaeyens, R

    2015-07-01

    The aim of the this study was to investigate the development of explosive leg power by using 2 similar jumping protocols (countermovement jump and standing broad jump) in 555 Belgian, high-level young soccer players, aged between 7 and 20 years. The total sample was divided into 3 longitudinal samples related to growth and maturation (pre-teenchildhood: (6-10 years;), early adolescence: (11-16 years;) and late adolescence: (17-20 years)), and 6 multilevel regression models were obtained. Generally, both jumping protocols emphasized that chronological age, body size dimensions (by means of fat mass in the late childhood and early adolescence groups, fat-free mass in the late adolescence group and stature--(not for CMJ in late childhood group) and fat mass in the late childhood and early adolescence groups, and fat-free mass in the late adolescence group) and motor coordination (one item of a 3-component test battery) are longitudinal predictors of explosive leg power from childhood to young adulthood. The contribution of maturational status was not investigated in this study. The present findings highlight the importance of including non-specific motor coordination in soccer talent development programs.

  10. Does Education Matter? Major League Baseball Players and Longevity

    ERIC Educational Resources Information Center

    Kalist, David E.; Peng, Yingwei

    2007-01-01

    The authors used duration analysis to examine the longevity of Major League Baseball players. Using data on players who were born between 1945 and 1964, the authors found that the hazard rate of death for players who only attended high school was almost 2.0 times higher than those players who attended a 4-year university, evidence that the…

  11. Technical, perceptual and motor skills in novice-expert water polo players: an individual discriminant analysis for talent development.

    PubMed

    DʼErcole, Alessandro A; DʼErcole, Cristina; Gobbi, Massimo; Gobbi, Fabio

    2013-12-01

    The 4 tasks (A, B, C, and Y) have the characteristic of containing one more element than the task performed before it. In fact, task B introduces the slalom which is not present in task A. Task C introduces the ball control that are not present in tasks A and B, whereas task Y introduces the slalom and ball control in a visual dual task situation developed in horizontal swimming over a distance of 20 m at maximum speed. This exercise not included in task C. These tasks were performed by a group of pre-adolescent players and national under 18 water polo players. The novice players showed that tasks B and C are predictors of task Y. Such characteristics were not present in the expert players. The novice players also had difficulty in performing task Y because of the visual-attention overload, a difficulty that was not present in the expert players. To improve the 4 skills, the coach of the novice players developed a technical-didactic program, which was checked 6 months after the pretest. The posttest was not significantly different from the pretest while the individual discriminant analysis identified the improvements in some novice players, which on elaboration proved significant, enabling us to distinguish 2 subgroups, one with higher learning rates and the other with lower learning rates. In the practical applications, we describe the didactic tools (task analysis) and the different levels of development of technical skills in water polo. Improvements in these skills are explained through computational models like the HMOSAIC (Hierarchical, Modular, Selection and Identification for Control) while the individual discriminant analysis enables us to do a longitudinal analysis that is not possible with cross-sectional models.

  12. Multi-player games on the cycle

    PubMed Central

    van Veelen, Matthijs; Nowak, Martin

    2011-01-01

    In multi-player games n individuals interact in any one encounter and derive a payoff from that interaction. We assume that individuals adopt one of two strategies, and we consider symmetric games, which means the payoff depends only on the number of players using either strategy, but not on any particular configuration of the encounter. On the cycle we assume that any string of n neighbouring players interacts. We study fixation probabilities of stochastic evolutionary dynamics. We derive analytical results on the cycle both for linear and exponential fitness for any intensity of selection, and compare those to results for the well-mixed population. As particular examples we study multi-player public goods games, stag hunt games and snowdrift games. PMID:21907215

  13. Experienced poker players are emotionally stable.

    PubMed

    Laakasuo, Michael; Palomäki, Jussi; Salmela, Mikko

    2014-10-01

    Online poker and poker subcultures have become exceedingly popular. Previous studies assessing experience and skill in poker have revealed that proficiency in emotion regulation is a consequential factor in explaining financial success in the game. We assessed (N=478) the associations between poker players' (recruited from online poker forums) level of poker experience and HEXACO-PI-R personality traits. The results indicate that a predisposition for emotional stability-that is, lower scores on emotionality-is linked to high levels of poker experience. Thus, in order to become a successful and experienced poker player, it helps to be able to "keep cool" under pressure. Further exploratory analyses suggest that players who prefer live play to online play are more likely to be extroverted and open to experiences. The results contribute to the extant literature on individual differences in personality in poker players, and in particular help to fill the interdisciplinary gap between personality and gambling research.

  14. Video Player Keyboard Shortcuts: MedlinePlus

    MedlinePlus

    ... of this page: https://medlineplus.gov/hotkeys.html Video Player Keyboard Shortcuts To use the sharing features ... of accessible keyboard shortcuts for our latest Health videos on the MedlinePlus site. These shortcuts allow you ...

  15. Replicator dynamics with turnover of players

    NASA Astrophysics Data System (ADS)

    Juul, Jeppe; Kianercy, Ardeshir; Bernhardsson, Sebastian; Pigolotti, Simone

    2013-08-01

    We study adaptive dynamics in games where players abandon the population at a given rate and are replaced by naive players characterized by a prior distribution over the admitted strategies. We demonstrate how such a process leads macroscopically to a variant of the replicator equation, with an additional term accounting for player turnover. We study how Nash equilibria and the dynamics of the system are modified by this additional term for prototypical examples such as the rock-paper-scissors game and different classes of two-action games played between two distinct populations. We conclude by showing how player turnover can account for nontrivial departures from Nash equilibria observed in data from lowest unique bid auctions.

  16. The hospital manager and game theory: chess master, poker player, or cooperative game player?

    PubMed

    Dowd, Steven B; Root, Alexey

    2003-01-01

    Hospital management can be seen as a game, and doctors, nurses, and health maintenance organizations are its players. The astute hospital manager realizes the interdependence of individual career strategies and the hospital's success, just as players in a game are interdependent on each other. Managers familiar with game theory may successfully transfer that knowledge to the hospital realm. They may recognize patterns and calculate outcomes like chess players, bluff other hospitals into folding services as poker players do, and cooperate with their own team to maximize productivity. Knowledge of game theory may also make the hospital manager's job.

  17. High School Football Players Use Their Helmets to Tackle Other Players Despite Knowing the Risks

    PubMed Central

    Kuriyama, Andrew M; Nakatsuka, Austin S

    2017-01-01

    There is greater attention to head-related injuries and concussions in American football. The helmet's structural safety and the way that football players use their helmets are important in preventing head injuries. Current strategies include penalizing players for high-risk behavior such as leading with their helmet or hitting an opposing player above the shoulder. Passive strategies include helmet modification to better protect the head of the players or to change the playing style of the players. Hawai‘i high school varsity football players were surveyed to determine how they use their helmets and how a new helmet design would affect their style of play. One hundred seventy-seven surveys were completed; 79% said that they used their helmet to hit an opposing player during a tackle and 46% said they made this contact intentionally. When asked about modifying helmets with a soft material on the outside, 48% said they thought putting a soft cover over a regular helmet would protect their head better. However, many participants said that putting a soft cover over their regular helmet was a bad idea for various reasons. Most young football players use their helmets to block or tackle despite being taught they would be penalized or potentially injured if they did so. By gaining a better understanding of why and how players use their helmets and how they would respond to new helmet designs, steps can be taken to reduce head injuries for all levels of play. PMID:28352493

  18. Explosive Strength Imbalances in Professional Basketball Players

    PubMed Central

    Schiltz, Marc; Lehance, Cédric; Maquet, Didier; Bury, Thierry; Crielaard, Jean-Michel; Croisier, Jean-Louis

    2009-01-01

    Context: Despite the high rate of lower limb injuries in basketball players, studies of the dominant-limb effect in elite athletes often neglect injury history. Objective: To determine lower limb explosive-strength asymmetries in professional basketball players compared with junior basketball players and control participants. Design: Cohort study. Setting: Academic medical institution. Patients or Other Participants: 15 professional basketball players, 10 junior basketball players, and 20 healthy men. Main Outcome Measure(s): We performed an isokinetic examination to evaluate the knee extensor (Ext) and flexor (Fl) concentric peak torque at 60°·s−1 and 240°·s−1 and (Fl only) eccentric peak torque at 30°·s−1 and 120°·s−1. Functional evaluation included countermovement jump, countermovement jump with arms, 10-m sprint, single-leg drop jump, and single-leg, 10-second continuous jumping. Variables were compared among groups using analysis of variance or a generalized linear mixed model for bilateral variables. Results: The 2 groups of basketball players demonstrated better isokinetic and functional performances than the control group did. No differences in functional or relative isokinetic variables were noted between professional and junior basketball players. Professional players with a history of knee injury failed to reach normal knee extensor strength at 60°·s−1. Knee Ext (60°·s−1) and Fl (eccentric 120°·s−1) torque values as well as 10-second continuous jumping scores were higher in those professional players without a history of knee injury than those with such a history. Compared with the group without a history of knee injury, the group with a history of knee injury maintained leg asymmetry ratios greater than 10% for almost all isokinetic variables and more than 15% for unilateral functional variables. Conclusions: The relative isokinetic and functional performances of professional basketball players were similar to those of junior

  19. Somatotype of Italian rugby players.

    PubMed

    Casagrande, G; Viviani, F

    1993-03-01

    Our aim was to collect lacking first-hand data on Italian rugby players. The Heath/Carter anthropometric somatotype method was applied to 28 "A" League performers (RP) aged 25 +/- 3.9 years of age. Their somatotypes and dimensions were compared with those found in previous studies on athletes involved in the same sporting activity, with data collected on 25 "sedentary" young Italians, and with Bailey et al.'s study on Canadians (1982). On average, the RP group resulted as being endomorphic mesomorphs (3.1 +/- 1.1 - 5.6 +/- 1.3 - 1.4 +/- 1.1), a result that is congruent with international data. They differed significantly from the balanced mesomorph CG (2.3 +/- 1.0 - 4.5 +/- 1.2 - 2.5 +/- 1.4) for all the measurements taken, apart from bi-epycondylar width. The peculiar somatotype scores found are congruent with the needs of rugby, an aerobic-anaerobic discipline which requires performers with great muscular power associated with a capacity to furnish energy, mainly through the anaerobic metabolism.

  20. Physical growth and changes in intermittent endurance run performance in young male Basque soccer players.

    PubMed

    Carvalho, Humberto M; Bidaurrazaga-Letona, Iraia; Lekue, José António; Amado, Markos; Figueiredo, António J; Gil, Susana M

    2014-01-01

    The present 4-year longitudinal study examined physical growth and development of intermittent endurance run performance in young Basque soccer players aged 10-15 years applying multilevel regression modeling. Anthropometry, predicted adult stature and Yo-Yo Intermittent Recovery level 1 test (Yo-Yo IR1) of players from the under-11 teams from the Athletic Club of Bilbao were measured at pre- and end-season (two measurements per year of study, n = 33 considered for analysis). A non-linear effect of age on intermittent endurance run was observed, with significantly higher increases in Yo-Yo IR1 between 10-11 year-old and 14-15 year-old players. The development of Yo-Yo IR1 performance in all the years of the study was influenced positively by training exposure during the seasons (P < 0.01) and independent of maturity status and body size (P > 0.05). The steady development of intermittent endurance run performance during pubertal years in adolescent Basque soccer players is partially influenced by training exposure.

  1. Rectus abdominis muscle strains in tennis players

    PubMed Central

    Maquirriain, Javier; Ghisi, Juan P; Kokalj, Antonio M

    2007-01-01

    Rectus abdominis muscle strains are common and debilitating injuries among competitive tennis players. Eccentric overload, followed by forced contraction of the non‐dominant rectus abdominis during the cocking phase of the service motion is the accepted injury mechanism. A tennis‐specific rehabilitation program emphasising eccentrics and plyometric strengthening of the abdominal wall muscles, contributes to the complete functional recovery in tennis players, and could help reduce recurrences. PMID:17957025

  2. Rectus abdominis muscle strains in tennis players.

    PubMed

    Maquirriain, Javier; Ghisi, Juan P; Kokalj, Antonio M

    2007-11-01

    Rectus abdominis muscle strains are common and debilitating injuries among competitive tennis players. Eccentric overload, followed by forced contraction of the non-dominant rectus abdominis during the cocking phase of the service motion is the accepted injury mechanism. A tennis-specific rehabilitation program emphasising eccentrics and plyometric strengthening of the abdominal wall muscles, contributes to the complete functional recovery in tennis players, and could help reduce recurrences.

  3. Effect of long-term unilateral activity on bone mineral density of female junior tennis players.

    PubMed

    Haapasalo, H; Kannus, P; Sievänen, H; Pasanen, M; Uusi-Rasi, K; Heinonen, A; Oja, P; Vuori, I

    1998-02-01

    High peak bone mass in early adulthood is an important protective factor against osteoporotic fractures in later life, but little is known about the effects of exercise on growing bone. The purpose of this cross-sectional study was to determine at which state of maturity (Tanner stage), the areal bone mineral density (BMD) differences between the playing and nonplaying arms of junior tennis players become obvious, and to clarify in each developmental stage which training and background variables, if any, could explain the interindividual differences in bones' response to mechanical loading. Ninety-one 7- to 17-year-old female tennis players and 58 healthy female controls were measured. In each Tanner stage, differences in BMD in playing and nonplaying (dominant and nondominant) arms (proximal humerus, humeral shaft, and distal radius) and BMD of the lumbar spine and nondominant distal radius were compared between the controls and players. Within each Tanner stage of players, the associations between training and background variables and BMD differences were analyzed with Spearman rank correlation coefficients. In players, BMD differences between the playing and nonplaying arms were significant (P < 0.05- < 0.001) in all Tanner stages, with the mean difference ranging from 1.6 to 15.7%. In controls, these dominant-to-nondominant arm differences were clearly smaller (ranging from -0.2 to 4.6%), but significant at some measured sites. In comparison with the relative side-to-side arm differences between the players and controls (i.e., examination of the training effect), the mean difference was not obvious and significant until the adolescent growth spurt (i.e., the girls in Tanner stage III with a mean age of 12.6 years). In the lumbar spine, significant BMD differences between players and controls were not found until Tanner stage IV (mean age 13.5 years; 8.7%, P < 0.05) and V (mean age 15.5 years; 12.4%, P < 0.05). In a nonloaded site of the skeleton (nondominant

  4. Soccer skill development in talented players.

    PubMed

    Huijgen, B C H; Elferink-Gemser, M T; Ali, A; Visscher, C

    2013-08-01

    The aim of the study was to gain insight into the development of soccer-specific skills and whether differences between talented players exist on the Loughborough Soccer Passing Test (LSPT). Two scores were derived from the LSPT: 1) execution time: time to complete 16 passes (speed) and 2) skill performance time: execution time including bonus and penalty time for accuracy. The study consisted of 2 parts, the first of which incorporated a quasi-longitudinal design with 270 talented players aged 10-18 years performing the LSPT (661 measurement occasions); multilevel modelling was applied. Secondly, differences between those players allowed to continue in the development program (selected, n=269) and players who were forced to leave (de-selected, n=50) were investigated using independent sample t-tests. The longitudinal data showed that the predicted execution time (i. e., speed) improved approximately 18% from age 10-18 years (P<0.05), skill performance time (i. e., combination of speed and accuracy) was predicted to improve approximately 32% (P<0.05). The second part showed that selected players outscored de-selected players only on skill performance time (P<0.05), not on execution time (P>0.05). In conclusion, in high-level youth soccer, the combination of speed and accuracy in soccer skills might be more important than speed alone.

  5. Characteristics of Smokeless Tobacco Use among High School Football Players as Related to Type of Smokeless Tobacco and Period of Use.

    ERIC Educational Resources Information Center

    Creath, Curtis J.; And Others

    1992-01-01

    Survey of high school football players (n=1,116) found that, compared to nonusers, adolescent athletes who tried smokeless tobacco were more likely to be white; to use cigarettes, alcohol, and cigars; and to have family users. Initial use was highest before age 14. Differences were found between snuff users and users of chewing tobacco. (Author/NB)

  6. Effects of combined and classic training on different isometric rate of force development parameters of leg extensors in female volleyball players: Discriminative analysis approach

    PubMed Central

    Branislav, Rajić; Milivoj, Dopsaj; Abella, Carlos Pablos; Deval, Vicente Caratalla; Siniša, Karišik

    2013-01-01

    Background: The aim of this study is to verify the effects of the combined and classic training of different isometric rates of force development (RFD) parameters of legs. Materials and Methods: Three groups of female athletes was tested: Experimental group (N = 12), classically trained group (N = 11), and control group (N = 20) of athletes. The isometric “standing leg extension” and “Rise on Toes” tests were conducted to evaluate the maximal force, time necessary time to reach it and the RFD analyzed at 100 ms, 180 ms, 250 ms from the onset, and 50-100% of its maximal result. Results: The maximal RFD of legs and calves are dominant explosive parameters. Special training enhanced the RFD of calves of GROUPSPEC at 100 ms (P = 0.05), at 180 ms (P = 0.039), at 250 ms (P = 0.039), at 50% of the Fmax (P = 0.031) and the Fmax (P = 0.05). Domination of GROUPSPEC toward GROUPCLASS and GROUPCONTROL is in case of legs at 100 ms (P = 0.04); at 180 ms (P = 0.04); at 250 ms (P = 0.00); at 50% of the Fmax (P = 0.01) and at the Fmax (P = 0.00); in case of calves at 100 ms (P = 0.07); 180 ms (P = 0.001); at 250 ms (P = 0.00); at 50% of the Fmax (P = 0.00) and at Fmax (P = 0.000). Conclusion: Dominant explosive factors are maximal RFD of leg extensors and calves, and legs at 250ms. Specific training enhanced explosiveness of calves of GROUPSPEC general and partial domination of GROUPSPEC by 87% over GROUPCLASS, and 35% over GROUPCONTROL. PMID:24497853

  7. Concussion among Swedish elite ice hockey players.

    PubMed Central

    Tegner, Y; Lorentzon, R

    1996-01-01

    OBJECTIVE: To evaluate the frequency of concussion in Swedish ice hockey and to establish a uniform grading and treatment model for concussions of different severity. METHODS: Frequency of concussion was investigated in two studies, one retrospective and one prospective. In the retrospective study, all Swedish elite ice hockey players (n = 265) were asked to answer a questionnaire on the number and treatment of previous concussions. Only concussions diagnosed by a doctor were recorded. The questionnaire was completed by 227 players (86%). In the prospective study, all injuries including concussions occurring during game and practice in the Swedish Elite League (n = 12 teams) were recorded during four years. The causes of injury, referees judgements, diagnosis, treatment, and time absent from ice hockey were registered on special cards. RESULTS: In the retrospective study, 51 out of 227 players (22%) in the Swedish Elite League reported at least one concussion. In the prospective study, 52 concussions were reported. The incidence of a concussion is at least one concussion every year/team or a yearly risk of about 5% for a player to sustain a concussion. Most concussions occurred during league play (81%). Body contact (checking or boarding) was the most common cause of concussions. The players were absent from full training and play on a mean of 6 d. CONCLUSIONS: As this injury is potentially dangerous it must be treated seriously according to a simple treatment model presented. In cases of repeated concussions during the same season, a longer period of time away from play is suggested. In players who have sustained several concussions over the years a thorough medical examination including EEG, CT/MRI, and neuropsychological tests should be performed. If any of these is pathological the player should be advised to give up ice hockey. PMID:8889123

  8. Landing limb posture in volleyball athletes with patellar tendinopathy: a pilot study.

    PubMed

    Kulig, K; Joiner, D G; Chang, Y-J

    2015-05-01

    The aims of this pilot study were to investigate how a novel sagittal plane kinematic measurement - the lower extremity contact angle (LECA) - relates to the landing dynamics of elite male volleyball athletes with and without patellar tendinopathy. The LECA was defined as the angle between the ground and the line connecting the center of pressure to the L5S1 marker. 18 athletes (9 with patellar tendinopathy and 9 with asymptomatic tendons) completed simulated spike jumps while instrumented for kinetic and kinematic analysis using a force platform and 3D motion analysis system. The patellar tendinopathic group demonstrated a significantly more acute LECA compared to the asymptomatic group (65.3°±2.2° vs. 69.1°±4.5°) and was the only kinematic or kinetic variable measured to discriminate between the 2 groups. The LECA further demonstrated less variability between trials than sagittal plane hip, knee, and ankle kinematics. Additionally, the LECA's - and not individual joints' - high correlation with the braking impulse ensures its predictive value for landing dynamics (r=- 0.890). The LECA has the potential to be a valuable tool to help assess jumping athletes in both injury prevention screening and as a variable that, if modified, could help alter the maladaptive behavior observed in symptomatic athletes.

  9. Complex network study of Brazilian soccer players

    NASA Astrophysics Data System (ADS)

    Onody, Roberto N.; de Castro, Paulo A.

    2004-09-01

    Although being a very popular sport in many countries, soccer has not received much attention from the scientific community. In this paper, we study soccer from a complex network point of view. First, we consider a bipartite network with two kinds of vertices or nodes: the soccer players and the clubs. Real data were gathered from the 32 editions of the Brazilian soccer championship, in a total of 13411 soccer players and 127 clubs. We find a lot of interesting and perhaps unsuspected results. The probability that a Brazilian soccer player has worked at N clubs or played M games shows an exponential decay while the probability that he has scored G goals is power law. Now, if two soccer players who have worked at the same club at the same time are connected by an edge, then a new type of network arises (composed exclusively by soccer player nodes). Our analysis shows that for this network the degree distribution decays exponentially. We determine the exact values of the clustering coefficient, the assortativity coefficient and the average shortest path length and compare them with those of the Erdös-Rényi and configuration model. The time evolution of these quantities are calculated and the corresponding results discussed.

  10. Injury incidence and balance in rugby players

    PubMed Central

    M, Jaco Ras; Puckree, Threethambal

    2014-01-01

    Objective : This study determined and correlated injury incidence and balance in rugby players. Methods: A prospective survey with balance testing was conducted on first year rugby academy players (N= 114). Injury incidence, static and dynamic balance were tested pre and post-season using a Biosway portable balance system. The data was analysed using paired and independent samples t-tests at p<0.05, Odds ratios, and Spearman’s correlation coefficients. Results: 75.50% participated, 71.40% were 18 years old, and 71.40% were White. Injury was sustained by 83% of players with the knee (25%) most commonly injured. Injury incidence was 1.52 per player with an injury rate of 5.95 injuries per 1000 match playing hours. The Stability Index increased significantly (p=0.03) by 15% in the medial/lateral direction post-season compared to pre-season. Significant differences in post-test anterior posterior and overall static and front and front right dynamic stability between injured and uninjured players were noted. Risk factors for injury included the scrum-half (14.80%) playing position, injuries in the 2nd half of the match (57%), and during contact (67%). Conclusion : Injury incidence was related to static and dynamic balance in forward right direction only. PMID:25674136

  11. Game Performance Evaluation in Male Goalball Players

    PubMed Central

    Molik, Bartosz; Morgulec-Adamowicz, Natalia; Kosmol, Andrzej; Perkowski, Krzysztof; Bednarczuk, Grzegorz; Skowroński, Waldemar; Gomez, Miguel Angel; Koc, Krzysztof; Rutkowska, Izabela; Szyman, Robert J

    2015-01-01

    Goalball is a Paralympic sport exclusively for athletes who are visually impaired and blind. The aims of this study were twofold: to describe game performance of elite male goalball players based upon the degree of visual impairment, and to determine if game performance was related to anthropometric characteristics of elite male goalball players. The study sample consisted of 44 male goalball athletes. A total of 38 games were recorded during the Summer Paralympic Games in London 2012. Observations were reported using the Game Efficiency Sheet for Goalball. Additional anthropometric measurements included body mass (kg), body height (cm), the arm span (cm) and length of the body in the defensive position (cm). The results differentiating both groups showed that the players with total blindness obtained higher means than the players with visual impairment for game indicators such as the sum of defense (p = 0.03) and the sum of good defense (p = 0.04). The players with visual impairment obtained higher results than those with total blindness for attack efficiency (p = 0.04), the sum of penalty defenses (p = 0.01), and fouls (p = 0.01). The study showed that athletes with blindness demonstrated higher game performance in defence. However, athletes with visual impairment presented higher efficiency in offensive actions. The analyses confirmed that body mass, body height, the arm span and length of the body in the defensive position did not differentiate players’ performance at the elite level. PMID:26834872

  12. The Hot Hand Exists in Volleyball and Is Used for Allocation Decisions

    ERIC Educational Resources Information Center

    Raab, Markus; Gula, Bartosz; Gigerenzer, Gerd

    2012-01-01

    The "hot hand" belief in sports refers to the conviction that a player has a higher chance of making a shot after two or three successful shots than after two or three misses (resulting in "streaks"). This belief is usually considered a cognitive fallacy, although it has been conjectured that in basketball the defense will…

  13. Does Testosterone Modulate Mood States and Physical Performance in Young Basketball Players?

    PubMed

    Miloski, Bernardo; Aoki, Marcelo S; de Freitas, Camila G; Schultz de Arruda, Ademir F; de Moraes, Helena S; Drago, Gustavo; Borges, Thiago O; Moreira, Alexandre

    2015-09-01

    This study aimed to examine and compare mood states profile and physical performance during different training phases between 2 groups of adolescent basketball players that were differentiated according to baseline testosterone concentration (T). The basketball players were submitted to an intensified training period (OVL) followed by a tapering period (TP). Twenty-three young male basketball players initiated the study. Experimental criteria data were used to stratify 16 players into high-testosterone (HTC) or low-testosterone (LTC) concentration groups. All the 16 athletes undertook 5 weeks of OVL followed by a 3-week TP. Saliva sampling, Yo-Yo intermittent recovery level 1 (Yo-Yo IRL1) test and the T-test were conducted at the beginning (T1), after OVL (T2), and after TP (T3). A similar increase in internal training load was observed during OVL when compared with TP in both groups (p < 0.05). No difference in mood states was observed between groups (p > 0.05); however, LTC displayed a higher score for fatigue (p < 0.05) and a lower score for energy index (p < 0.05) in OVL, compared with TP. A significant improvement in the Yo-Yo IRL1 test and the T-test was observed (T1 to T3) (p < 0.05), with no difference between groups (p > 0.05). In conclusion, these results suggest that LTC athletes may be more susceptible to changes in mood states during intensified training periods. In addition, data indicate that a periodized training program successfully improved the physical performance (endurance and agility) of young basketball players; however, this improvement was not affected by testosterone level.

  14. Nutrition education by a registered dietitian improves dietary intake and nutrition knowledge of a NCAA female volleyball team.

    PubMed

    Valliant, Melinda W; Emplaincourt, Heather Pittman; Wenzel, Rachel Kieckhaefer; Garner, Bethany Hilson

    2012-06-01

    Eleven female participants from a NCAA Division I volleyball team were evaluated for adequate energy and macronutrient intake during two off-seasons. Total energy and macronutrient intake were assessed by food records and results were compared against estimated needs using the Nelson equation. Dietary intervention was employed regarding the individual dietary needs of each athlete as well as a pre- and post-sports nutrition knowledge survey. Post dietary intervention, total energy, and macronutrient intake improved, as well as a significant improvement in sports nutrition knowledge (p < 0.001). Nutrition education is useful in improving dietary intake and nutrition knowledge of female athletes.

  15. Nutrition Education by a Registered Dietitian Improves Dietary Intake and Nutrition Knowledge of a NCAA Female Volleyball Team

    PubMed Central

    Valliant, Melinda W.; Pittman Emplaincourt, Heather; Wenzel, Rachel Kieckhaefer; Garner, Bethany Hilson

    2012-01-01

    Eleven female participants from a NCAA Division I volleyball team were evaluated for adequate energy and macronutrient intake during two off-seasons. Total energy and macronutrient intake were assessed by food records and results were compared against estimated needs using the Nelson equation. Dietary intervention was employed regarding the individual dietary needs of each athlete as well as a pre- and post-sports nutrition knowledge survey. Post dietary intervention, total energy, and macronutrient intake improved, as well as a significant improvement in sports nutrition knowledge (p < 0.001). Nutrition education is useful in improving dietary intake and nutrition knowledge of female athletes. PMID:22822449

  16. Restricted connections among distinguished players support cooperation

    NASA Astrophysics Data System (ADS)

    Perc, Matjaž; Szolnoki, Attila; Szabó, György

    2008-12-01

    We study the evolution of cooperation within the spatial prisoner’s dilemma game on a square lattice where a fraction of players μ can spread their strategy more easily than the rest due to a predetermined larger teaching capability. In addition, players characterized by the larger teaching capability are allowed to temporarily link with distant opponents of the same kind with probability p , thus introducing shortcut connections among the distinguished players. We show that these additional temporary connections are able to sustain cooperation throughout the whole range of the temptation to defect. Remarkably, we observe that, as the temptation to defect increases the optimal μ decreases, and moreover only minute values of p warrant the best promotion of cooperation. Our study thus indicates that influential individuals must be few and sparsely connected in order for cooperation to thrive in a defection-prone environment.

  17. Restricted connections among distinguished players support cooperation.

    PubMed

    Perc, Matjaz; Szolnoki, Attila; Szabó, György

    2008-12-01

    We study the evolution of cooperation within the spatial prisoner's dilemma game on a square lattice where a fraction of players mu can spread their strategy more easily than the rest due to a predetermined larger teaching capability. In addition, players characterized by the larger teaching capability are allowed to temporarily link with distant opponents of the same kind with probability p , thus introducing shortcut connections among the distinguished players. We show that these additional temporary connections are able to sustain cooperation throughout the whole range of the temptation to defect. Remarkably, we observe that, as the temptation to defect increases the optimal mu decreases, and moreover only minute values of p warrant the best promotion of cooperation. Our study thus indicates that influential individuals must be few and sparsely connected in order for cooperation to thrive in a defection-prone environment.

  18. Prevalence of Problematic Video Gaming among Ontario Adolescents

    ERIC Educational Resources Information Center

    Turner, Nigel E.; Paglia-Boak, Angela; Ballon, Bruce; Cheung, Joyce T. W.; Adlaf, Edward M.; Henderson, Joanna; Chan, Vincy; Rehm, Jurgen; Hamilton, Hayley; Mann, Robert E.

    2012-01-01

    Video game playing has become a very popular activity among adolescents. Its impact on the mental health and well-being of players is just beginning to be explored. This paper reports on the prevalence of problematic gaming in a representative sample of 2,832 Ontario students in grades 7 to 12. The survey included questions about the school grade,…

  19. Comparing spondylolysis in cricketers and soccer players

    PubMed Central

    Gregory, P; Batt, M; Kerslake, R

    2004-01-01

    Objective: To determine whether the location of spondylolysis in the lumbar spine of athletes differs with biomechanical factors. Methods: Single photon emission computerised tomography and reverse gantry computerised tomography were used to investigate 42 cricketers and 28 soccer players with activity related low back pain. Sites of increased scintigraphic uptake in the posterior elements of the lumbar spine and complete or incomplete fracture in the pars interarticularis were compared for these two sports. Results: Thirty seven (90.4%) cricketers and 23 (82.1%) soccer players studied had sites of increased uptake. In cricketers, these sites were on the left of the neural arch of 49 lumbar vertebrae and on the right of 33 vertebrae. In soccer players there was a significantly different proportion, with 17 sites on the left and 28 on the right (difference of 22.0%; 95% confidence interval (CI) 0.04 to 0.38). Lower lumbar levels showed increased scintigraphic uptake more frequently than did higher levels, although the trend was reversed at L3 and L4 in soccer. Forty spondylolyses were identified in the lumbar vertebrae of the cricketers and 35 spondylolyses in the soccer players. These comprised 26 complete and 14 incomplete fractures in the cricketers, and 25 complete and 10 incomplete fractures in the soccer players. Similar numbers of incomplete fractures were found either side of the neural arch in soccer players, but there were more incomplete fractures in the left pars (14) than in the right (2) in cricketers. The proportion of incomplete fractures either side of the neural arch was significantly different between cricket players and soccer players (difference of 37.5%; 95% CI 0.02 to 0.65). Most complete fractures were at L5 (66.7%) and more were found at L3 (15.7%) than L4 (6.9%). However, incomplete fractures were more evenly spread though the lower three lumbar levels with 41.7% at L5, 37.5% at L4, and 20.8% at L3. Conclusions: Fast bowling in cricket is

  20. Characteristics of youth soccer players aged 13–15 years classified by skill level

    PubMed Central

    Malina, Robert M; Ribeiro, Basil; Aroso, João; Cumming, Sean P

    2007-01-01

    Objective To evaluate the growth, maturity status and functional capacity of youth soccer players grouped by level of skill. Subjects The sample included 69 male players aged 13.2–15.1 years from clubs that competed in the highest division for their age group. Methods Height and body mass of players were measured and stage of pubic hair (PH) was assessed at clinical examination. Years of experience in football were obtained at interview. Three tests of functional capacity were administered: dash, vertical jump and endurance shuttle run. Performances on six soccer‐specific tests were converted to a composite score which was used to classify players into quintiles of skill. Multiple analysis of covariance, controlling for age, was used to test differences among skill groups in experience, growth status and functional capacity, whereas multiple linear regression analysis was used to estimate the relative contributions of age, years of training in soccer, stage of PH, height, body mass, the height×weight interaction and functional capacities to the composite skill score. Results The skill groups differed significantly in the intermittent endurance run (p<0.05) but not in the other variables. Only the difference between the highest and lowest skill groups in the endurance shuttle run was significant. Most players in the highest (12 of 14) and high (11 of 14) skill groups were in stages PH 4 and PH 5. Pubertal status and height accounted for 21% of the variance in the skill score; adding aerobic resistance to the regression increased the variance in skill accounted for to 29%. In both regressions, the coefficient for height was negative. Conclusion Adolescent soccer players aged 13–15 years classified by skill do not differ in age, experience, body size, speed and power, but differ in aerobic endurance, specifically at the extremes of skill. Stage of puberty and aerobic resistance (positive coefficients) and height (negative coefficient) are significant

  1. Effects of Student Skill Level on Knowledge, Decision Making, Skill Execution and Game Performance in a Mini-Volleyball Sport Education Season

    ERIC Educational Resources Information Center

    Mahedero, Pilar; Calderón, Antonio; Arias-Estero, José Luis; Hastie, Peter A.; Guarino, Anthony J.

    2015-01-01

    The purpose of the paper was to examine the effects of student skill level on knowledge, decision making, skill execution and game performance in a mini-volleyball Sport Education season. Forty-eight secondary school students from two classes participated in a 12 lesson season. Knowledge, decision-making and skill execution (components of game…

  2. Evaluating the Relation between Dominant and Non-Dominant Hand Perimeters and Handgrip Strength of Basketball, Volleyball, Badminton and Handball Athletes

    ERIC Educational Resources Information Center

    Kaplan, Defne Öcal

    2016-01-01

    In this study, it's aimed to evaluate the relation between dominant and non-dominant hand perimeters and handgrip strength of basketball, volleyball, badminton and handball athletes. Totally 101 active athletes (49 females, 52 male), of the average age in female 20±1.42 years, in male 21±1.99 years, joined to this study. Height, body weight, BMI…

  3. 30 Former NFL Players Pledge Their Brains for Research

    MedlinePlus

    ... 163416.html 30 Former NFL Players Pledge Their Brains for Research Donations will be used to study ... retired players who have pledged to donate their brains to research on a devastating brain disease that ...

  4. Robust Football Players Tracking Method for Soccer Scene Analysis

    NASA Astrophysics Data System (ADS)

    Kataoka, Hirokatsu; Aoki, Yoshimitsu

    For the analysis of soccer videos, positional information of players and ball is very essential. In order to obtain trajectories of the players, robust tracking for multiple players is highly required. In this paper, we propose a method to track multiple players in a soccer video which is captured by a single camera. In the case of capturing the video from a single view, there might be a lot of occluded situations of players. In order to overcome this problem, we propose a robust tracking method for multiple players by combining Particle Filter and Real AdaBoost Classifier. First, each target player is tracked by using Particle Filter. Next, an occluded situation is automatically detected by checking a distance between the target players. Then we resample the center of the gravities by classifier's detection after Particle Filter tracking. We show the experimental results and effectiveness of our proposed method.

  5. High-protein-PUFA supplementation, red blood cell membranes, and plasma antioxidant activity in volleyball athletes.

    PubMed

    Malaguti, Marco; Baldini, Marta; Angeloni, Cristina; Biagi, Pierluigi; Hrelia, Silvana

    2008-06-01

    The authors evaluated the role of a high-protein, low-calorie, polyunsaturated fatty-acid (PUFA) -supplemented diet on anthropometric parameters, erythrocyte-membrane fatty-acid composition, and plasma antioxidant defenses of nonprofessional volleyball athletes. The athletes were divided in two groups: One (n = 5) followed the Mediterranean diet, and the other (n = 6) followed a high-protein, low-calorie diet with a 3-g/day fish-oil supplementation. All the athletes had anthropometric measurements taken, both at the beginning and at the end of the study, which lasted for 2 months. Body-mass index and total body fat were significantly diminished in the second group, while they remained unchanged in the first. Plasma total antioxidant activity (TAA) was significantly increased in the plasma of both groups, with no differences between the groups, suggesting that physical activity, not the different diets, is the main contributor to the increase of plasma TAA. The second group showed a significant increase in erythrocyte-membrane PUFA content and in the unsaturation index value (UI) because of the fish-oil supplementation.A high-protein, low-carbohydrate, fish-oil-supplemented diet seems to be useful only when the aim of the diet is to obtain weight loss in a short-term period. The significant increase in the UI of erythrocyte membranes indicates the potential for harm, because a high intake of PUFA might increase susceptibility to lipid peroxidation not counterbalanced by a higher increase in TAA. Adherence to the Mediterranean diet seems to be the better choice.

  6. Effects of an additional basketball and volleyball program on motor abilities of fifth grade elementary school students.

    PubMed

    Selmanović, Aleksandar; Milanović, Dragan; Custonja, Zrinko

    2013-06-01

    The aim was to evaluate the transformational effects of an additional weekly PE session based on team sports (basketball and volleyball) on students' motor status. The research was conducted on a sample of 125 eleven-year-old boys divided into three groups (two experimental and one control) which were examined by 12 motor tests at the beginning and at the end of the 9-month period. The tests included evaluation of explosive power dynamic and static strength endurance, co-ordination, flexibility and hand frequency motion. Although all three treatments together, complemented by the natural growth and developmental factors, induced significant quantitative changes, the results showed the highest motor improvements in the basketball experimental group, followed by the volleyball experimental group. While explosive power mainly contributed toward significant difference between the control and experimental groups in the final measurement, univarate test results also showed distinctive improvements in dynamic strength, hand frequency motion and various factors of co-ordination within experimental groups. The general conclusion points to the fact that even one additional PE session per week of the given program is sufficient to produce significant changes in motor abilities of elementary school fifth graders. Therefore the authors' support the legal provisions of mandatory implementation of extra-curricular forms of physical activity in elementary schools.

  7. Visual Attentional Orienting in Developing Hockey Players.

    ERIC Educational Resources Information Center

    Enns, James T.; Richards, James C.

    1997-01-01

    Covert visual orienting was measured in 13 twelve-year-old and 11 fifteen-year-old hockey players and in 13 college students with no hockey training. Found that high-skill 15-year-olds were better able than all other groups to take advantage of the general alerting effect produced by the sudden onset of a cue. (MDM)

  8. Knee injuries in women collegiate rugby players.

    PubMed

    Levy, A S; Wetzler, M J; Lewars, M; Laughlin, W

    1997-01-01

    We evaluated the prevalence and patterns of knee injuries in 810 women collegiate rugby players. Injuries that resulted in players missing at least one game were recorded and a questionnaire was used to delineate players' rugby and knee injury history. There were 76 total knee injuries in 58,296 exposures. This resulted in a 1.3 knee injury rate per 1000 exposures. Twenty-one anterior cruciate ligament tears were reported for a 0.36 incidence per 1000 exposures. Other injuries included meniscal tears (25), medical collateral ligament sprains (23), patellar dislocations (5), and posterior cruciate ligament tears (2). Sixty-one percent of the medial collateral ligament sprains occurred in rugby forwards and 67% of anterior cruciate ligament tears occurred in rugby backs. All other injuries occurred with equal frequency in backs and forwards. This study demonstrates that knee injury rates in women's collegiate rugby are similar to those reported for other women's collegiate sports. The overall rate of anterior cruciate ligament injury in women's rugby, however, is slightly higher than that reported for women soccer and basketball players.

  9. Assessing Soccer Players and Educating Soccer Parents

    ERIC Educational Resources Information Center

    Skirka, Nicholas

    2005-01-01

    This article offers suggestions on how to assess the abilities of young soccer athletes and ways to educate parents or guardians on how to maintain an attitude that most benefits and supports the players. The abilities of young athletes on a team vary, and the expectations of both team members and parents are high, thus presenting a major…

  10. Motivational Traits of Elite Young Soccer Players

    ERIC Educational Resources Information Center

    Stewart, Craig; Meyers, Michael C.

    2004-01-01

    Among the most overlooked aspects in the development of elite young soccer players is that of specific psychological traits. Of those traits, motivation has important implications for programs whose objectives are identification and cultivation of young, skilled performers. The growth in popularity of soccer by youth and the successes experienced…

  11. Juggling key players in NMD initiation.

    PubMed

    Bono, Fulvia

    2014-08-05

    In this issue of Structure, Melero and colleagues use electron microscopy combined with biochemistry to provide structural insight into the complex between SMG1, SMG8, SMG9, UPF1, and UPF2, elucidating how key players in nonsense-mediated mRNA decay assemble at the initial steps of the process.

  12. Low Back Pain in a Tennis Player.

    ERIC Educational Resources Information Center

    Bracker, Mark; And Others

    1988-01-01

    A group of physicians meet to discuss a case in which a middle-aged tennis player suffers from low back pain. The diagnosis, treatment and management of the case are discussed. The article is one in an occasional series. (JL)

  13. Match Duration and Number of Rallies in Men’s and Women’s 2000–2010 FIVB World Tour Beach Volleyball

    PubMed Central

    Palao, José Manuel; Valades, David; Ortega, Enrique

    2012-01-01

    After the 2000 Olympic Games, the Fédération Internationale de Volleyball (FIVB) modified the scoring system used in beach volleyball from side-out to a rally point system. The goal was to facilitate the comprehension of the game and to stabilize match duration. The purpose of this study was to assess the duration and number of rallies in men’s and women’s beach volleyball matches (2000–2010 FIVB World Tour). Data from 14,432 men’s matches and 14,175 women’s matches of the 2000–2010 World Tour were collected. The variables studied were: match duration, total rallies per set and match, number of sets, team that won the set and match, type of match (equality in score), and gender. The average match duration in beach volleyball is stable, ranging from 30 to 64 minutes, regardless of the number of sets, the stage of the tournament (qualifying round or main draw), or gender. The average number of rallies per match were 78–80 for two-set matches and 94–96 for three-set matches. Matches from the main draw are more balanced than matches from the qualifying round. More balanced matches (smaller point difference between teams) have longer durations. It is not clear why there is no relationship between the number of rallies and match duration. Future studies are needed to clarify this aspect. The results can serve as a reference to guide beach volleyball training (with regard to duration and number of rallies) and to help understand the effect of the rule change. PMID:23486703

  14. Exploring Online Game Players' Flow Experiences and Positive Affect

    ERIC Educational Resources Information Center

    Chiang, Yu-Tzu; Lin, Sunny S. J.; Cheng, Chao-Yang; Liu, Eric Zhi-Feng

    2011-01-01

    The authors conducted two studies to explore online game players' flow experiences and positive affect. Our findings indicated that online game are capable of evoking flow experiences and positive affect, and games of violent or nonviolent type may not arouse players' aggression. The players could be placed into four flow conditions: flow,…

  15. Training Patterns of Wheelchair Basketball Players in Turkey

    ERIC Educational Resources Information Center

    Tatar, Yasar

    2008-01-01

    The aim of this study was to analyze technical drills, warm-up and cool-down exercises used by wheelchair basketball players of the Turkish league in relation to training sessions. 33 male wheelchair basketball players participated in the study (mean age 26.6[plus or minus]5,95 years). All players reported that they used warm-up exercises before…

  16. 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…

  17. Are poker players all the same? Latent class analysis.

    PubMed

    Dufour, Magali; Brunelle, Natacha; Roy, Élise

    2015-06-01

    Poker is the gambling game that is currently gaining the most in popularity. However, there is little information on poker players' characteristics and risk factors. Furthermore, the first studies described poker players, often recruited in universities, as an homogeneous group who played in only one of the modes (land based or on the Internet). This study aims to identify, through latent class analyses, poker player subgroups. A convenience sample of 258 adult poker players was recruited across Quebec during special events or through advertising in various media. Participants filled out a series of questionnaires (Canadian Problem Gambling Index, Beck Depression, Beck Anxiety, erroneous belief and alcohol/drug consumption). The latent class analysis suggests that there are three classes of poker players. Class I (recreational poker players) includes those who have the lowest probability of engaging intensively in different game modes. Participants in class II (Internet poker players) all play poker on the Internet. This class includes the highest proportion of players who consider themselves experts or professionals. They make a living in part or in whole from poker. Class III (multiform players) includes participants with the broadest variety of poker patterns. This group is complex: these players are positioned halfway between professional and recreational players. Results indicate that poker players are not an homogeneous group identified simply on the basis of the form of poker played. The specific characteristics associated with each subgroup points to vulnerabilities that could potentially be targeted for preventive interventions.

  18. Concussion Incidences and Severity in Secondary School Varsity Football Players.

    ERIC Educational Resources Information Center

    Gerberich, Susan Goodwin; And Others

    1983-01-01

    Study of Minnesota high school football players found an injury rate of 78 per 100 players; 19/100 players reported a concussion experience characterized by loss of consciousness/awareness. Of these, 69 percent returned to play the same day. Illegal blocking and tackling contributed to increased concussion. Lasting effects were prevalent. (GC)

  19. Clug; Community Land Use Game. Player's Manual with Selected Readings.

    ERIC Educational Resources Information Center

    Feldt, Allan G.

    CLUG (Community Land Use Game) is designed to provide players with an understanding of several underlying factors affecting the growth of an urban region. It has been used with players from junior high to graduate school and also with non-students. It unites concepts from sociology, economics, and geography. Players invest in land, construct…

  20. How to keep A players productive.

    PubMed

    Berglas, Steven

    2006-09-01

    After graduating from Harvard Business School with highest honors, Jane rapidly moved up the corporate ladder at a large advertising firm, racking up promotions and responsibilities along the way. By the time she became the company's creative director, she was, in everyone's estimation, an A player--one of the organization's most gifted and productive employees. But although she received an extraordinarily generous pay package and had what some people considered to be one of the most stimulating jobs in the company, Jane felt underappreciated and was talking to head-hunters. Eventually, she was lured away to a competing company that, by her own admission, offered less-challenging work. Both Jane and the advertising firm she left behind lost out. Of course, not all A players are as vulnerable as Jane. Some superstars soar to stunning heights, needing little or no special attention, and have the natural self-confidence and brilliance to stay at the top of their game with elegance and grace. But as every manager knows, megastars with manageable egos are rare. Far more common are people like Jane who are striving to satisfy an inner need for recognition that is often a sign of irrationally low self-esteem. According to the author--an executive coach, management consultant, and former faculty member of the department of psychiatry at Harvard Medical School--if you do not carefully manage the often unconscious need A players have for kudos and appreciation, they will burn out in a way that is damaging to them and unproductive for you. The key is understanding what makes your A players tick. The author suggests that you assist your stars by offering them authentic praise, helping them set boundaries, and teaching them to play nicely with subordinates. In the process, you can turn these high performers into even more effective players.

  1. Anthropometric Characteristics of Spanish Professional Basketball Players

    PubMed Central

    Alejandro, Vaquera; Santiago, Santos; Gerardo, Villa José; Carlos, Morante Juan; Vicente, García-Tormo

    2015-01-01

    The study of elite basketball players’ anthropometric characteristics alongside those of body composition contributes significantly to their profiling as professional athletes and plays an important role in the selection process, as these characteristics can have a significant impact on performance. In the current study, 110 professional basketball players from a series of Spanish professional Leagues (ACB, LEB and EBA) and youth level National Teams (U20 and U18) had their anthropometric profiles measured and compared to determine differences between them. Furthermore, all 110 players were divided into three different categories according to their playing position: guards, forwards and centres. The results obtained show no significant differences between players in different competitions in weight, height and the sum of skinfolds. Nonetheless, there were several differences related to body fat content (13.03% in ACB players and 10.52% in the lower categories and National Teams). There were also several differences found between the different playing positions amongst all playing levels in body mass (79.56 ± 2.41, 91.04 ± 1.51 and 104.56 ± 1.73 kg), height (182.28 ± 0.96, 195.65 ± 1.00 and 204.08 ± 0.67 cm), skinfold distribution and perimeters. However, there were no significant differences in body fat content between the different playing positions. The conclusions obtained from this study provide a better understanding to basketball specialists regarding the selection process of players at the elite level, especially on the transition from youth elite programs to men’s elite leagues. PMID:26240653

  2. Forearm Skin Blood Flow After Kinesiology Taping in Healthy Soccer Players: An Exploratory Investigation

    PubMed Central

    Woodward, Kirsty A.; Unnithan, Vish; Hopkins, Nicola D.

    2015-01-01

    Context Kinesiology tape (KT) has become popular among athletes for both injury prevention and rehabilitation due to its reported therapeutic effects, including facilitation of lymphatic flow and enhanced peripheral blood flow. However, evidence to support such claims is insufficient. Objective To determine whether KT improves skin blood flow (SkBF) responses in young, elite soccer players. Design Randomized crossover study. Setting Research laboratory. Patients or Other Participants Thirteen healthy, elite, adolescent male soccer players (age = 14.7 ± 0.6 years). Intervention(s) Participants completed 2 experimental trials; during trial 1, the volar aspect of the dominant forearm was taped. Forearm SkBF was measured within the taped area and 3 cm lateral to the taped area. During trial 2, no tape was applied to either site. Both trials were performed within 7 days. Main Outcome Measure(s) Baseline and maximal thermally (42°C) stimulated SkBF responses were assessed using laser Doppler flowmetry. Continuously measured SkBF and derived mean arterial pressure obtained at 5-minute intervals were used to calculate cutaneous vascular conductance (CVC), the primary outcome measure. Results No differences were observed for baseline SkBF or CVC between trials or measurement sites. After local heating, no differences were evident for SkBF or CVC between trials or measurement sites. Conclusions Our findings suggest that, in healthy, trained adolescent males, KT was not associated with increased forearm SkBF. PMID:26445024

  3. A retrospective study on anthropometrical, physical fitness, and motor coordination characteristics that influence dropout, contract status, and first-team playing time in high-level soccer players aged eight to eighteen years.

    PubMed

    Deprez, Dieter N; Fransen, Job; Lenoir, Matthieu; Philippaerts, Renaat M; Vaeyens, Roel

    2015-06-01

    The goal of this article was twofold, and a 2-study approach was conducted. The first study aimed to expose the anthropometrical, physical performance, and motor coordination characteristics that influence dropout from a high-level soccer training program in players aged 8-16 years. The mixed-longitudinal sample included 388 Belgian youth soccer players who were assigned to either a "club group" or a "dropout group." In the second study, cross-sectional data of anthropometry, physical performance, and motor coordination were retrospectively explored to investigate which characteristics influence future contract status (contract vs. no contract group) and first-team playing time for 72 high-level youth soccer players (mean age = 16.2 years). Generally, club players outperformed their dropout peers for motor coordination, soccer-specific aerobic endurance, and speed. Anthropometry and estimated maturity status did not discriminate between club and dropout players. Contract players jumped further (p = 0.011) and had faster times for a 5-m sprint (p = 0.041) than no contract players. The following prediction equation explains 16.7% of the variance in future playing minutes in adolescent youth male soccer players: -2,869.3 + 14.6 × standing broad jump. Practitioners should include the evaluation of motor coordination, aerobic endurance, and speed performances to distinguish high-level soccer players further succeeding a talent development program and future dropout players, between 8 and 16 years. From the age of 16 years, measures of explosivity are supportive when selecting players into a future professional soccer career.

  4. A retrospective study on anthropometrical, physical fitness and motor coordination characteristics that influence drop out, contract status and first-team playing time in high-level soccer players, aged 8 to 18 years.

    PubMed

    Deprez, Dieter; Fransen, Job; Lenoir, Matthieu; Philippaerts, Renaat M; Vaeyens, Roel

    2014-12-02

    The goal of this manuscript was twofold and a two-study approach was conducted. The first study aimed to expose the anthropometrical, physical performance and motor coordination characteristics that influence drop out from a high-level soccer training program in players aged 8-16 years. The mixed-longitudinal sample included 388 Belgian youth soccer players who were assigned to either a 'club group' or a 'drop out group'. In the second study, cross-sectional data of anthropometry, physical performance and motor coordination were retrospectively explored to investigate which characteristics influence future contract status (contract vs. no contract group) and first-team playing time for 72 high-level youth soccer players (mean age=16.2 y).Generally, club players outperformed their drop out peers for motor coordination, soccer-specific aerobic endurance and speed. Anthropometry and estimated maturity status did not discriminate between club and drop out players. Contract players jumped further (p=0.011) and had faster times for a 5m sprint (p=0.041) than no contract players. The following prediction equation explains 16.7% of the variance in future playing minutes in adolescent youth male soccer players: -2869.3 + 14.6 * standing broad jump.Practitioners should include the evaluation of motor coordination, aerobic endurance and speed performances to distinguish high-level soccer players further succeeding a talent development program and future drop out players, between 8 and 16 years. From the age of 16 years, measures of explosivity are supportive when selecting players into a future professional soccer career.

  5. PERFORMANCE OF HIGH SCHOOL FOOTBALL PLAYERS ON CLINICAL MEASURES OF DEEP CERVICAL FLEXOR ENDURANCE AND CERVICAL ACTIVE RANGE OF MOTION: IS HISTORY OF CONCUSSION A FACTOR?

    PubMed Central

    Ruediger, Thomas; Alsalaheen, Bara; Bean, Ryan

    2016-01-01

    Background More than one million adolescent athletes participated in organized high school sanctioned football during the 2014-15 season. These athletes are at risk for sustaining concussion. Although cervical spine active range of motion (AROM) and deep neck flexor endurance may serve a preventative role in concussion, and widespread clinical use of measurements of these variables, reference values are not available for this population. Cost effective, clinically relevant methods for measuring neck endurance are also well established for adolescent athletes. Purpose The purpose of this study was to report reference values for deep cervical flexor endurance and cervical AROM in adolescent football players and examine whether differences in these measures exist in high school football players with and without a history of concussion. Methods Concussion history, cervical AROM, and deep neck flexor endurance were measured in 122 high school football players. Reference values were calculated for AROM and endurance measures; association were examined between various descriptive variables and concussion. Results No statistically significant differences were found between athletes with a history of concussion and those without. A modest inverse correlation was seen between body mass and AROM in the sagittal and transverse planes. Conclusion The results of this study indicate that the participants with larger body mass had less cervical AROM in some directions. While cervical AROM and endurance measurements may not be adequate to identify adolescents with a history of previous concussions among high school football players. However, if a concussion is sustained, these measures can offer a baseline to examine whether cervical AROM is affected as compared to healthy adolescents. Level of Evidence 2c PMID:27104049

  6. The developmental activities of elite soccer players aged under-16 years from Brazil, England, France, Ghana, Mexico, Portugal and Sweden.

    PubMed

    Ford, Paul R; Carling, Christopher; Garces, Marco; Marques, Mauricio; Miguel, Carlos; Farrant, Andrew; Stenling, Andreas; Moreno, Jansen; Le Gall, Franck; Holmström, Stefan; Salmela, John H; Williams, Mark

    2012-01-01

    The developmental activities of 328 elite soccer players aged under-16 years from Brazil, England, France, Ghana, Mexico, Portugal and Sweden were examined using retrospective recall in a cross-sectional research design. The activities were compared to the early diversification, early specialisation, and early engagement pathways. Players started their involvement in soccer at approximately 5 years of age. During childhood, they engaged in soccer practice for a mean value of 185.7, s = 124.0 h · year(-¹), in soccer play for 186.0, s = 125.3 h · year(-¹), and in soccer competition for 37.1, s = 28.9 h · year(-¹). A mean value of 2.3, s = 1.6 sports additional to soccer were engaged in by 229 players during childhood. Players started their participation in an elite training academy at 11 to 12 years of age. During adolescence, they engaged in soccer practice for a mean value of 411.9, s = 184.3 h · year(-¹), in soccer play for 159.7, s = 195.0 h · year(-¹), and in soccer competition for 66.9, s = 48.8 h · year(-¹). A mean value of 2.5, s = 1.8 sports other than soccer were engaged in by 132 players during this period. There were some relatively minor differences between countries, but generally the developmental activities of the players followed a mixture of the early engagement and specialisation pathways, rather than early diversification.

  7. Tracking soccer players based on homography among multiple views

    NASA Astrophysics Data System (ADS)

    Iwase, Sachiko; Saito, Hideo

    2003-06-01

    In this paper, we propose a method of tracking soccer players using multiple views. As many researchers have done on soccer scene analysis by using trajectories of the playser and the soccer ball, it is desirable to track soccer players robustly. Soccer player tracking enables strategy analysis, scene recovery, making scenes for broadcasting, and automatic system of the camera control. However, soccer is a sport that occlusion occurs in many cases, and tracking often fails by the occlusion of the players. It is difficult to track the players by using a single camera alone. Therefore, we use multiple view images to avoid the occlusion problem, so that we can obtain robustness in player tracking. As a first step, inner-camera operation is performed independently in each camera to track the players. In any case that player can not be tracked in the camera, inter-camera operation is performed as a second step. Tracking information of all cameras are integrated by using the geometrical relationship between cameras called homography. Inter-camera operation makes it possible to get the location of the player who is not detected in the image, who is occluded by the other player, and who is outside the angle of view. Experimental results show that robust player tracking is available by tracking advantage using multiple cameras.

  8. Reduced attentional capture in action video game players.

    PubMed

    Chisholm, Joseph D; Hickey, Clayton; Theeuwes, Jan; Kingstone, Alan

    2010-04-01

    Recent studies indicate that playing action video games improves performance on a number of attention-based tasks. However, it remains unclear whether action video game experience primarily affects endogenous or exogenous forms of spatial orienting. To examine this issue, action video game players and non-action video game players performed an attentional capture task. The results show that action video game players responded quicker than non-action video game players, both when a target appeared in isolation and when a salient, task-irrelevant distractor was present in the display. Action video game players additionally showed a smaller capture effect than did non-action video game players. When coupled with the findings of previous studies, the collective evidence indicates that extensive experience with action video games may enhance players' top-down attentional control, which, in turn, can modulate the negative effects of bottom-up attentional capture.

  9. Investigation of characteristics and risk factors of sports injuries in young soccer players: a retrospective study

    PubMed Central

    2013-01-01

    Background The participation of children and adolescents in sports has become increasingly frequent, including soccer. This growing involvement gives rise to concerns regarding the risk of sports injuries. Therefore, the aim of the present study was to describe the musculoskeletal injuries in young soccer players. Methods 301 male soccer players with a mean age 14.67 ± 2.08 years were randomly recruited. The Referred Condition Inquiry was used to collect information on the mechanism of injury and anatomic site affected as well as personal data on the participants. The variables were analyzed based on the degree of association using Goodman’s test for contrasts between multinomial populations, with the p < 0.05. Results Among the 301 athletes, 24.25% reported at least one injury. With regard to height, taller individuals reported more injuries than shorter individuals (62.5% and 37.5%, respectively; p < 0.05). Injuries were more frequent among players with a training duration greater than five years (69.65%) in comparison to those who trained for a shorter duration (30.35%) (p < 0.05). The lower limbs, especially the ankle/foot and knee, were the most affected anatomic sites. Impact was the most common mechanism of injury. Conclusion The young practitioners of soccer analyzed had low rates of injury. The main causal mechanism was the impact. A taller height and longer exposure to training were the main risk factors for injury among young soccer players. PMID:23602027

  10. Volume of Physical Activity and Injury Occurrence in Young Basketball Players

    PubMed Central

    Gianoudis, Jenny; Webster, Kate E.; Cook, Jill

    2008-01-01

    Participation in organised, competitive physical activity by young athletes is increasing rapidly. This is concurrent with an increase in sporting injuries in the young population. This pilot study aimed to compare the weekly volume and types of physical activity in young basketball players injured and not injured during the season. Detailed physical activity and injury data were prospectively collected in 46 school-level basketball players aged 14 to 18 years. Participants completed physical activity logs which documented the type of physical activity undertaken, what the activity consisted of (i.e. training, competition) and the level at which it was played on a daily basis. Allied health staff completed a weekly injury form. Results showed that injured and uninjured athletes participated in a similar volume of total weekly physical activity over the season. However, injured athletes (p = 0.04) and athletes who specifically sustained overuse injuries (p = 0.01) participated in a greater amount of basketball refereeing than uninjured athletes. Based on these findings it was concluded that greater participation in running-type physical activity such as refereeing, as an addition to training and competition, may predispose the young basketball player to increased injury risk. Future research using larger sample sizes are required to further investigate the role of participation volume and type on injury occurrence in adolescent athletes. Key points Basketball players participating in larger amounts of running-type physical activity, in addition to regular training and competition, may be predisposed to overuse injury Future studies using larger sample sizes are required to investigate the precise volumes of physical activity that increase injury risk This would assist in the development of participation guidelines to decrease the current injury rates observed in the young athletic population. PMID:24150146

  11. High prevalence of physical inactivity among adolescents living with HIV/AIDS

    PubMed Central

    Tanaka, Luana Fiengo; Latorre, Maria do Rosário Dias de Oliveira; da Silva, Aline Medeiros; Konstantyner, Thais Claudia Roma de Oliveira; Peres, Stela Verzinhasse; Marques, Heloisa Helena de Sousa

    2015-01-01

    Objective: To assess the prevalence of physical inactivity among adolescents with HIV/AIDS, as well as associated factors. Methods: Ninety-one adolescents (from 10 to 19 years old) with HIV/AIDS who are patients at a university follow-up service were interviewed. Anthropometric data (weight, height, and waist circumference) were measured twice; clinical information was obtained from medical records, and habitual physical activity was assessed by a questionnaire proposed by Florindo et al. The cutoff point for sedentariness was 300 minutes/week. Results: The prevalence of inadequate height for age, malnutrition, and overweight/obesity was 15.4%, 9.9% and 12.1%, respectively. The most common physical activities were soccer (44.4%), volleyball (14.4%) and cycling (7.8%). The median times spent with physical activity and walking/bicycling to school were 141 min and 39 min, respectively. Most adolescents (71.4%) were sedentary and this proportion was higher among girls (p=0.046). Conclusions: A high prevalence of physical inactivity among adolescents with HIV/AIDS was observed, similar to the general population. Promoting physical activity among adolescents, especially among girls with HIV/AIDS, as well as monitoring it should be part of the follow-up routine of these patients. PMID:25907024

  12. Evolutionary game theory: molecules as players.

    PubMed

    Bohl, Katrin; Hummert, Sabine; Werner, Sarah; Basanta, David; Deutsch, Andreas; Schuster, Stefan; Theissen, Günter; Schroeter, Anja

    2014-12-01

    In this and an accompanying paper we review the use of game theoretical concepts in cell biology and molecular biology. This review focuses on the subcellular level by considering viruses, genes, and molecules as players. We discuss in which way catalytic RNA can be treated by game theory. Moreover, genes can compete for success in replication and can have different strategies in interactions with other genetic elements. Also transposable elements, or "jumping genes", can act as players because they usually bear different traits or strategies. Viruses compete in the case of co-infecting a host cell. Proteins interact in a game theoretical sense when forming heterodimers. Finally, we describe how the Shapley value can be applied to enzymes in metabolic pathways. We show that game theory can be successfully applied to describe and analyse scenarios at the molecular level resulting in counterintuitive conclusions.

  13. Telemetry and Communication IP Video Player

    NASA Technical Reports Server (NTRS)

    OFarrell, Zachary L.

    2011-01-01

    Aegis Video Player is the name of the video over IP system for the Telemetry and Communications group of the Launch Services Program. Aegis' purpose is to display video streamed over a network connection to be viewed during launches. To accomplish this task, a VLC ActiveX plug-in was used in C# to provide the basic capabilities of video streaming. The program was then customized to be used during launches. The VLC plug-in can be configured programmatically to display a single stream, but for this project multiple streams needed to be accessed. To accomplish this, an easy to use, informative menu system was added to the program to enable users to quickly switch between videos. Other features were added to make the player more useful, such as watching multiple videos and watching a video in full screen.

  14. The excluded player in coalition formation.

    PubMed

    van Beest, Ilja; Wilke, Henk; van Dijk, Eric

    2003-02-01

    Coalition research generally assumes that people strive to maximize their share of the coalition payoff and that they exclude others from joining a coalition if these others are not needed to obtain the coalition payoff. In two experiments, the authors show that this view is too narrow and that willingness to include such others is dependent on the extent to which people feel that exclusion affects the payoff of the excluded player. This finding was moderated by social value orientations. Proselfs were not affected by the consequences for the excluded players. Prosocials were less willing to exclude others the more harmful were the consequences of exclusion. Results are related to research on social exclusion, the do-no-harm principle, and social value orientations.

  15. Cervical spine injuries in football players.

    PubMed

    Thomas, B E; McCullen, G M; Yuan, H A

    1999-01-01

    Cervical spine injuries have been estimated to occur in 10% to 15% of football players, most commonly in linemen, defensive ends, and linebackers. The overwhelming majority of such injuries are self-limited, and full recovery can be expected. However, the presenting symptoms of serious cervical spine injuries may closely resemble those of minor injuries. The orthopaedic surgeon frequently must make a judgment, on the field or later in the office, about the advisability of returning the athlete to the game. These decisions can have an enormous impact on the player and his family. Most severe cervical spine injuries share the common mechanism of application of an axial load to the straightened spine. Avoiding techniques that employ head-down "spear" tackling and wearing properly fitted equipment markedly reduce the risk of serious injury.

  16. Ankle Bracing, Fatigue, and Time to Stabilization in Collegiate Volleyball Athletes

    PubMed Central

    Shaw, Megan Y; Gribble, Phillip A; Frye, Jamie L

    2008-01-01

    Context: Fatigue has been shown to disrupt dynamic stability in healthy volunteers. It is not known if wearing prophylactic ankle supports can improve dynamic stability in fatigued athletes. Objective: To determine the type of ankle brace that may be more effective at providing dynamic stability after a jump-landing task during normal and fatigued conditions. Design: Two separate repeated-measures analyses of variance with 2 within-subjects factors (condition and time) were performed for each dependent variable. Setting: Research laboratory. Patients or Other Participants: Ten healthy female collegiate volleyball athletes participated (age  =  19.5 ± 1.27 years, height  =  179.07 ± 7.6 cm, mass  =  69.86 ± 5.42 kg). Intervention(s): Athletes participated in 3 separate testing sessions, applying a different bracing condition at each session: no brace (NB), Swede-O Universal lace-up ankle brace (AB), and Active Ankle brace (AA). Three trials of a jump-landing task were performed under each condition before and after induced functional fatigue. The jump-landing task consisted of a single-leg landing onto a force plate from a height equivalent to 50% of each participant's maximal jump height and from a starting position 70 cm from the center of the force plate. Main Outcome Measure(s): Time to stabilization in the anterior-posterior (APTTS) and medial-lateral (MLTTS) directions. Results: For APTTS, a condition-by-time interaction existed (F2,18  =  5.55, P  =  .013). For the AA condition, Tukey post hoc testing revealed faster pretest (2.734 ± 0.331 seconds) APTTS than posttest (3.817 ± 0.263 seconds). Post hoc testing also revealed that the AB condition provided faster APTTS (2.492 ± 0.271 seconds) than AA (3.817 ± 0.263 seconds) and NB (3.341 ± 0.339 seconds) conditions during posttesting. No statistically significant findings were associated with MLTTS. Conclusions: Fatigue increased APTTS for the AA condition. Because the

  17. EVALUATION OF PAINFUL SHOULDER IN BASEBALL PLAYERS

    PubMed Central

    Miyazaki, Alberto Naoki; Fregoneze, Marcelo; Santos, Pedro Doneux; da Silva, Luciana Andrade; do Val Sella, Guilherme; Junior, Adriano Fernando Mendes; Soares, André Lopes; Aihara, Leandro Jun; Checchia, Sérgio Luiz

    2015-01-01

    Objective: To assess the relationship between shoulder mobility and strength and the presence of pain among baseball players. Methods: Between April and July 2009, 55 baseball players were assessed by the Shoulder and Elbow Group of the School of Medical Sciences, Santa Casa de Misericórdia, São Paulo. They were all males, aged between 15 and 33 years (mean of 21); they attended an average of three training sessions per week and had been doing this sport for a mean of 10 years. Results: 14 of the 55 players evaluated were pitchers, and 20 reported pain during the pitching motion. The mean values for lateral and medial rotation and range of motion (ROM) in the dominant shoulder were, respectively, 110 °, 61 ° and 171 °, with a statistically significant difference in relation to the non-dominant limb. Pitchers had greater gains in lateral rotation and deficits in medial rotation than did non-pitchers. Pain presented a statistically significant correlation with diminished ROM, greater length of time playing the sport and situations of “shoulder at risk”. Conclusions: Statistically significant differences in dominant shoulder mobility were found, with increased lateral rotation, diminished medial rotation and smaller ROM, in relation to the contralateral limb. There was a statistically significant relationship between the pitcher's position and greater gain in lateral rotation and diminished medial rotation. There were statistically significant correlations between pain and diminished ROM, greater length of time playing the sport and situations of “shoulder at risk”. There was a statistical tendency suggesting that players with diminished medial rotation of the dominant shoulder presented a relationship with pain. PMID:27028320

  18. Soccer injuries in female youth players.

    PubMed

    Schiff, Melissa A

    2007-04-01

    A cross-sectional survey of injuries among female youth soccer players found 44.6% (95% confidence interval 34.9%-54.8%) had ever been injured. The injury incidence rate for the current season was 2.2/1000 soccer exposure hours (95% CI 1.5-3.1). Future studies should evaluate modifiable risk factors in youth to identify injury prevention strategies.

  19. Musculoskeletal problems in soccer players: current concepts.

    PubMed

    Longo, Umile Giuseppe; Loppini, Mattia; Cavagnino, Roberta; Maffulli, Nicola; Denaro, Vincenzo

    2012-05-01

    Soccer is the most popular sport worldwide, with about 200 million players, both professionals and amateurs. Because of its popularity, it has been often proposed to be able to prevent or cure health problems around the world. Although participation in football leads to significant physical benefits such as improving well-being, extending life expectancy and reducing the likelihood of several major non-communicable diseases, the possibility to incur in soccer injuries must be considered. On average, an elite football player suffers from 1.5-7.6 injuries each 1,000 hours of training and 12-35 injuries each 1000 hours of match. Several risk factors for soccer injuries have been described. The most important of them are the level of play (the risk appears to be higher in professional than amateur players); the exercise load; and the standard of training. The injury prevention program "The 11", developed with the support of the Federation Internationale de Football Association (FIFA), aims to reduce the impact of intrinsic injury risk factors in soccer, and it has been validated in that sport. A successive modified version of "The 11" ("The 11+") has been also shown to be effective in preventing injuries in young female soccer players. The FIFA 11+ provided more than 40% of reduction of the risk of injury. Several factors can be related to the risk of injury during sport. Therefore different exercises or factors might have been responsible for efficacy of the FIFA 11+ to prevent injuries. Several improvements have been surely achieved in the last ten years, but further investigation is needed to improve the benefits of playing soccer on human health.

  20. 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

  1. Tibia and fibula fractures in soccer players.

    PubMed

    Boden, B P; Lohnes, J H; Nunley, J A; Garrett, W E

    1999-01-01

    We performed a retrospective review of 31 athletes who sustained a fracture of the lower leg from a direct blow while playing soccer. Fifteen fractures involved both the tibia and fibula 11 only the tibia, and 5 only the fibula. Information was collected using a standardized questionnaire. The mean follow-up from the time of injury was 30 months. Injuries typically occurred in young, competitive athletes during game situations. The mechanisms were broadly classified into several categories: contact during a slide tackle (13, 42%), a collision with the goalkeeper (8, 26%), two opposing players colliding while swinging for a loose ball (7, 23%), or a player being kicked by a standing opponent (3, 10%). The majority of fractures (26, 90%) occurred while the athletes were wearing shin guards. The point of impact was with the shin guard prior to the fracture in 16 cases (62%). Return to competitive soccer averaged 40 weeks for combined tibia and fibula fractures, 35 weeks for isolated tibia fractures, and 18 weeks for isolated fibula fractures. Injuries were associated with a high incidence of major complications (12 out of 31, 39%), especially in concurrent tibia and fibula fractures (8 out of 15, 50%). These findings suggest that lower leg fractures in soccer players are serious injuries, often necessitating a prolonged recovery time. In addition, this study questions the ability of shin guards to protect against fractures.

  2. The El Dorado of Handball? Foreign Female Players Stay, while Domestic Players Return from Abroad.

    PubMed

    Bon, Marta; Topič, Mojca Doupona; Šibila, Marko

    2016-04-01

    The main purpose of this research was to study the characteristics of migration in European women's handball based on the Slovenian example and to find the differences between the foreigners coming to Slovenia and the Slovenians transferring to foreign clubs. The research was based on 16 open face-to-face semi-structured interviews (8 Slovenians (age 29.5 ± 6.2 years) and 8 foreigners (age 35.5 ± 8.7 years)). We found out that the most powerful factor in foreigners was the financial one, while within Slovenian players it was their personal desire for progression within their sport, the club's reputation and poor conditions in their previous club. The results confirm that when making a decision on transfer, all players had the support of family and friends, while the clubs of foreign players were not as supportive. Most interviewees considered their careers successful and did not regret going abroad. The research indicates that the largest differences discovered between Slovenians and foreigners were that foreign female players chose to stay in the new country (Slovenia), while domestic players returned home after few years playing abroad. In conclusion, the results show that in top-level handball there are important differences between migration models which are based on nationality and also that the migration models change throughout time, which is largely connected with the socioeconomic events in the country of origin or transfer.

  3. The El Dorado of Handball? Foreign Female Players Stay, while Domestic Players Return from Abroad

    PubMed Central

    Topič, Mojca Doupona; Šibila, Marko

    2016-01-01

    Abstract The main purpose of this research was to study the characteristics of migration in European women’s handball based on the Slovenian example and to find the differences between the foreigners coming to Slovenia and the Slovenians transferring to foreign clubs. The research was based on 16 open face-to-face semi-structured interviews (8 Slovenians (age 29.5 ± 6.2 years) and 8 foreigners (age 35.5 ± 8.7 years)). We found out that the most powerful factor in foreigners was the financial one, while within Slovenian players it was their personal desire for progression within their sport, the club’s reputation and poor conditions in their previous club. The results confirm that when making a decision on transfer, all players had the support of family and friends, while the clubs of foreign players were not as supportive. Most interviewees considered their careers successful and did not regret going abroad. The research indicates that the largest differences discovered between Slovenians and foreigners were that foreign female players chose to stay in the new country (Slovenia), while domestic players returned home after few years playing abroad. In conclusion, the results show that in top-level handball there are important differences between migration models which are based on nationality and also that the migration models change throughout time, which is largely connected with the socioeconomic events in the country of origin or transfer. PMID:28149349

  4. The influence of expertise on brain activation of the action observation network during anticipation of tennis and volleyball serves.

    PubMed

    Balser, Nils; Lorey, Britta; Pilgramm, Sebastian; Naumann, Tim; Kindermann, Stefan; Stark, Rudolf; Zentgraf, Karen; Williams, A Mark; Munzert, Jörn

    2014-01-01

    In many daily activities, and especially in sport, it is necessary to predict the effects of others' actions in order to initiate appropriate responses. Recently, researchers have suggested that the action-observation network (AON) including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In the present study, we examined the influence of task-specific expertise on the AON by investigating differences between two expert groups trained in different sports while anticipating action effects. Altogether, 15 tennis and 16 volleyball experts anticipated the direction of observed tennis and volleyball serves while undergoing functional magnetic resonance imaging (fMRI). The expert group in each sport acted as novice controls in the other sport with which they had only little experience. When contrasting anticipation in both expertise conditions with the corresponding untrained sport, a stronger activation of AON areas (SPL, SMA), and particularly of cerebellar structures, was observed. Furthermore, the neural activation within the cerebellum and the SPL was linearly correlated with participant's anticipation performance, irrespective of the specific expertise. For the SPL, this relationship also holds when an expert performs a domain-specific anticipation task. Notably, the stronger activation of the cerebellum as well as of the SMA and the SPL in the expertise conditions suggests that experts rely on their more fine-tuned perceptual-motor representations that have improved during years of training when anticipating the effects of others' actions in their preferred sport. The association of activation within the SPL and the cerebellum with the task achievement suggests that these areas are the predominant brain sites involved in fast motor predictions. The SPL reflects the processing of domain-specific contextual information and the cerebellum the usage of a predictive internal model to solve the anticipation task.

  5. Sympathetic enhancement in futsal players but not in football players after repeated sprint ability test

    PubMed Central

    Chen, Yung-Sheng; Liao, Chih-Jung; Lu, Wan-An; Kuo, Cheng-Deng

    2015-01-01

    Background Heart rate variability (HRV) can disclose the specific adaptation of sympathovagal modulation to exercise. This study investigated the change in HRV measures after anaerobic and aerobic intermittent exercises in university football and futsal players. Method 36 male university students with physically active lifestyle (n=14), football (n=12), and futsal (n=10) participated in this study. The participants completed the repeated sprint ability (RSA) test and Yo-Yo (YY) intermittent recovery test level 1 in randomised order. ECG signals of the participants were recorded in supine position 15 min before and 30 min after exercises. Before exercise, and 5 and 30 min after exercise, the blood pressures were also taken. Results In the RSA protocol, the percentage changes in normalised high-frequency power (nHFP) were significantly decreased, while the percentage changes in the very low/high frequency power ratio (VLHR) and low/high frequency power ratio (LHR) were significantly increased in futsal players after exercise, as compared with the controls. No significant changes in all HRV indices were found in the YY protocol, except the respiratory frequency. Conclusions After exercise, the percent decrease in vagal modulation in futsal players was significantly reduced, while the percentage increase in sympathetic modulation in futsal players was significantly enhanced in the RSA test, but not in the YY test, as compared with the control group. The increase in sympathetic activity and the decrease in vagal activity in the futsal players were greater than the corresponding increase and decrease in the football players in the RSA test. PMID:27900135

  6. Yo-Yo Intermittent Recovery Test Performance in Subelite Gaelic Football Players From Under Thirteen to Senior Age Groups.

    PubMed

    Roe, Mark; Malone, Shane

    2016-11-01

    Roe, M and Malone, S. Yo-Yo intermittent recovery test performance in subelite Gaelic football players from under thirteen to senior age groups. J Strength Cond Res 30 (11): 3187-3193, 2016-Gaelic football is indigenous to Ireland and has similar locomotion profiles to soccer and Australian Football. Given the increasing attention on long-term player development, investigations on age-related variation in Yo-Yo intermittent recovery test level 1 (Yo-YoIR1) performance may provide useful information in talent identification, program design, and player monitoring. Therefore, the aim of this study was to evaluate Yo-YoIR1 performance across Gaelic football age groups. Male participants (n = 355) were recruited from division one, Gaelic football teams. Participants were allocated to one of the 7 groups according to respective age groups from under 13 (U13), under 14, under 15 (U15), under 16 (U16), minor, under 21 (U21), to senior age groups. Total Yo-YoIR1 distance (m) increased progressively from U13 (885 ± 347 m) to U16 (1,595 ± 380 m) equating to a rate of change of 180.2%. In comparison to U13, total distance at minor (1,206 ± 327 m) increased by 136.4%. Subsequent increases were observed in U21 (1,585 ± 445 m) and senior players (2,365 ± 489). Minimum (800-880 m) and maximum (2,240-2,280 m) total distances were comparable for U15, U16, and U21 players. Differences in total distance (m) for all age groups were statistically significant when compared to U13 players (p < 0.002). In comparison to U13 players, the magnitude of differences between age groups for total distance was deemed to be large (effect size > 0.8). Similar trends were observed for maximum velocity and estimated V[Combining Dot Above]O2max. The evolution of Yo-YoIR1 performance in Gaelic football players from adolescents to adulthood highlights how maturation may influence sport-related running ability. Changes in Yo-YoIR1 performance should be closely monitored to optimize interventions for

  7. Physical therapists' role in prevention and management of patellar tendinopathy injuries in youth, collegiate, and middle-aged indoor volleyball athletes

    PubMed Central

    Kulig, Kornelia; Noceti-DeWit, Lisa M.; Reischl, Stephen F.; Landel, Rob F.

    2015-01-01

    Patellar tendinopathy is highly prevalent in all ages and skill levels of volleyball athletes. To illustrate this, we discuss the clinical, biomechanical, and ultrasound imaging presentation and the intervention strategies of three volleyball athletes at different stages of their athletic career: youth, middle-aged, and collegiate. We present our examination strategies and interpret the data collected, including visual movement analysis and dynamics, relating these findings to the probable causes of their pain and dysfunction. Using the framework of the EdUReP concept, incorporating Education, Unloading, Reloading, and Prevention, we propose intervention strategies that target each athlete's specific issues in terms of education, rehabilitation, training, and return to sport. This framework can be generalized to manage patellar tendinopathy in other sports requiring jumping, from youth to middle age, and from recreational to elite competitive levels. PMID:26537811

  8. Bone geometry and strength adaptations to physical constraints inherent in different sports: comparison between elite female soccer players and swimmers.

    PubMed

    Ferry, Beatrice; Duclos, Martine; Burt, Lauren; Therre, Perrine; Le Gall, Franck; Jaffré, Christelle; Courteix, Daniel

    2011-05-01

    Sports training characterized by impacts or weight-bearing activity is well known to induce osteogenic effects on the skeleton. Less is known about the potential effects on bone strength and geometry, especially in female adolescent athletes. The aim of this study was to investigate hip geometry in adolescent soccer players and swimmers compared to normal values that stemmed from a control group. This study included 26 swimmers (SWIM; 15.9 ± 2 years) and 32 soccer players (SOC; 16.2 ± 0.7 years), matched in body height and weight. A group of 15 age-matched controls served for the calculation of hip parameter Z-scores. Body composition and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA). DXA scans were analyzed at the femoral neck by the hip structure analysis (HSA) program to calculate the cross-sectional area (CSA), cortical dimensions (inner endocortical diameter, ED; outer width and thickness, ACT), the centroid (CMP), cross-sectional moment of inertia (CSMI), section modulus (Z), and buckling ratio (BR) at the narrow neck (NN), intertrochanteric (IT), and femoral shaft (FS) sites. Specific BMDs were significantly higher in soccer players compared with swimmers. At all bone sites, every parameter reflecting strength (CSMI, Z, BR) favored soccer players. In contrast, swimmers had hip structural analysis (HSA) Z-scores below the normal values of the controls, thus denoting weaker bone in swimmers. In conclusion, this study suggests an influence of training practice not only on BMD values but also on bone geometry parameters. Sports with high impacts are likely to improve bone strength and bone geometry. Moreover, this study does not support the argument that female swimmers can be considered sedentary subjects regarding bone characteristics.

  9. Adolescent Pregnancy.

    PubMed

    Leftwich, Heidi K; Alves, Marcus Vinicius Ortega

    2017-04-01

    Adolescent pregnancy, although on the decline, represents a significant public health concern. Often adolescents present late to prenatal care, either from lack of knowledge, fear of consequences, limited access, stigma, or all of the above. Although multifaceted, there are many risks both to mother and child that are increased in adolescent pregnancy. Many are unintended and are at risk for repeat adolescent pregnancy, especially within the first 2 years. Risks include but are not limited to: low birth weight, preterm delivery, stillbirth, and preeclampsia, as well as feelings of social isolation, delayed or neglected educational goals, and maternal depression.

  10. Player preferences among new and old violins

    PubMed Central

    Fritz, Claudia; Curtin, Joseph; Poitevineau, Jacques; Morrel-Samuels, Palmer; Tao, Fan-Chia

    2012-01-01

    Most violinists believe that instruments by Stradivari and Guarneri “del Gesu” are tonally superior to other violins—and to new violins in particular. Many mechanical and acoustical factors have been proposed to account for this superiority; however, the fundamental premise of tonal superiority has not yet been properly investigated. Player's judgments about a Stradivari's sound may be biased by the violin's extraordinary monetary value and historical importance, but no studies designed to preclude such biasing factors have yet been published. We asked 21 experienced violinists to compare violins by Stradivari and Guarneri del Gesu with high-quality new instruments. The resulting preferences were based on the violinists’ individual experiences of playing the instruments under double-blind conditions in a room with relatively dry acoustics. We found that (i) the most-preferred violin was new; (ii) the least-preferred was by Stradivari; (iii) there was scant correlation between an instrument's age and monetary value and its perceived quality; and (iv) most players seemed unable to tell whether their most-preferred instrument was new or old. These results present a striking challenge to conventional wisdom. Differences in taste among individual players, along with differences in playing qualities among individual instruments, appear more important than any general differences between new and old violins. Rather than searching for the “secret” of Stradivari, future research might best focused on how violinists evaluate instruments, on which specific playing qualities are most important to them, and on how these qualities relate to measurable attributes of the instruments, whether old or new. PMID:22215592

  11. Making star teams out of star players.

    PubMed

    Mankins, Michael; Bird, Alan; Root, James

    2013-01-01

    Top talent is an invaluable asset: In highly specialized or creative work, for instance, "A" players are likely to be six times as productive as "B" players. So when your company has a crucial strategic project, why not multiply all that firepower and have a team of your best performers tackle it? Yet many companies hesitate to do this, believing that all-star teams don't work: Big egos will get in the way. The stars won't be able to work with one another. They'll drive the team Leader crazy. Mankins, Bird, and Root of Bain & Company believe it's time to set aside that thinking. They have seen all-star teams do extraordinary work. But there is a right way and a wrong way to organize them. Before you can even begin to assemble such a team, you need to have the right talent management practices, so you hire and develop the best people and know what they're capable of. You have to give the team appropriate incentives and leaders and support staffers who are stars in their own right. And projects that are ill-defined or small scale are not for all-star teams. Use them only for critical missions, and make sure their objectives are clear. Even with the right setup, things can still go wrong. The wise executive will take steps to manage egos, prune non-team-players, and prevent average coworkers from feeling completely undervalued. She will also invest a lot of time in choosing the right team Leader and will ask members for lots of feedback to monitor how that leader is doing.

  12. Player preferences among new and old violins.

    PubMed

    Fritz, Claudia; Curtin, Joseph; Poitevineau, Jacques; Morrel-Samuels, Palmer; Tao, Fan-Chia

    2012-01-17

    Most violinists believe that instruments by Stradivari and Guarneri "del Gesu" are tonally superior to other violins--and to new violins in particular. Many mechanical and acoustical factors have been proposed to account for this superiority; however, the fundamental premise of tonal superiority has not yet been properly investigated. Player's judgments about a Stradivari's sound may be biased by the violin's extraordinary monetary value and historical importance, but no studies designed to preclude such biasing factors have yet been published. We asked 21 experienced violinists to compare violins by Stradivari and Guarneri del Gesu with high-quality new instruments. The resulting preferences were based on the violinists' individual experiences of playing the instruments under double-blind conditions in a room with relatively dry acoustics. We found that (i) the most-preferred violin was new; (ii) the least-preferred was by Stradivari; (iii) there was scant correlation between an instrument's age and monetary value and its perceived quality; and (iv) most players seemed unable to tell whether their most-preferred instrument was new or old. These results present a striking challenge to conventional wisdom. Differences in taste among individual players, along with differences in playing qualities among individual instruments, appear more important than any general differences between new and old violins. Rather than searching for the "secret" of Stradivari, future research might best focused on how violinists evaluate instruments, on which specific playing qualities are most important to them, and on how these qualities relate to measurable attributes of the instruments, whether old or new.

  13. Racism in soccer? Perception of challenges of black and white players by white referees, soccer players, and fans.

    PubMed

    Wagner-Egger, Pascal; Gygax, Pascal; Ribordy, Farfalla

    2012-02-01

    This experiment investigated challenge evaluations in soccer and their relation to prejudice: more precisely, whether skin colour may influence judgments of soccer tackles. Three groups of participants (soccer players, referees,and soccer fans) were asked to evaluate challenges, featuring Black and White players as aggressors and victims in a mixed-design study. Results showed that participants made some differentiations between Black and White players in a challenge evaluation task. Participants were more likely to consider within-group challenges as fouls and were faster to consider challenges made by Black players as fouls. On the other hand, fouls made by White players were seen as more severe. There were no major differences between the participating groups, suggesting that the observed effects were independent of how good players were or whether the participants were referees or not.

  14. Occupational acroosteolysis in a guitar player.

    PubMed

    Baran, R; Tosti, A

    1993-02-01

    A case of occupational acroosteolysis in a 24-year-old classical guitar player is reported. Nail tenderness was the only manifestation of initial acroosteolysis, which was due to mechanical stress on the fingers. Radiographs showed initial resorption of the 2nd, 3rd and 4th finger of the left hand. The authors review the clinical and radiological features of acroosteolysis. The pathogenesis of acroosteolysis is discussed as well as the different diseases that may cause destructive changes of the distal phalangeal bones.

  15. Acing common skin problems in tennis players.

    PubMed

    Basler, R S; Garcia, M A

    1998-12-01

    The following measures can help prevent skin disorders in tennis players: wearing properly fitted shoes to avoid tennis toe, talon noir, and calluses; applying lubricants to protect against blisters and chafing; washing skin thoroughly to reduce the risk of acne mechanica; and wearing a hat and sunscreen to guard against photoinjury. 'Stringer's fingers' can be prevented by breaking the habit of adjusting the racket strings after each point. Should these disorders become troublesome, conservative treatments are usually effective. For example, calluses may be carefully pared, and pain from a subungual hemorrhage can be relieved by piercing the toenail with a hot paper clip.

  16. Elbow and Shoulder Lesions of Baseball Players*

    PubMed Central

    2008-01-01

    George Eli Bennett was born in Claryville, NY, in the Catskill Mountains, in 1885 [3]. His parents both died by the time he was 11, leaving him the need to work while going to school, but he excelled in school and sports. He played semipro baseball at the age of 16. After high school he work in various jobs in the Midwest before he could afford to attend the University of Maryland Medical School, from which he graduated in 1908. At the age of 25 in 1910, he joined the staff at the Johns Hopkins Hospital, where he remained until his resignation in 1947. Dr. Bennett was one of a few men who served as President of both the American Orthopaedic Association and the American Academy of Orthopaedic Surgeons. While Dr. Bennett made many contributions to orthopaedic surgery, including children’s and nonoperative orthopaedics, he was best known for his work in sports medicine (undoubtedly related to his being a gifted athlete). His fame extended well beyond the orthopaedic community, for he treated many famous athletes. Sports Illustrated recognized him upon his death in an article entitled, “Mender of Immortals” [4]. His intimate knowledge of sports undoubtedly contributed to his sage judgments. At an emotional dinner in 1958 many famous athletes sometimes tearfully paid tribute to Dr. Bennett. Joe Garagiola commented on the occasion, “After listening to that all-star team of players Dr. Bennett has mended, I’m sorry I didn’t break my leg” [4]. Among Dr. Bennett’s many publications, including those related to sports, we have chosen one [2] of two articles [1,2] he wrote on elbow and shoulder problems in baseball players. He described the now well-known degenerative changes and periarticular calcific deposits that occur in the elbows and shoulders of pitchers. Some of these, he suggested, were not symptomatic and he advised against treatment. Dr. Bennett commented, however, “Since professional athletes are human beings, not supermen, general health often

  17. What Differentiates Professional Poker Players from Recreational Poker Players? A Qualitative Interview Study

    ERIC Educational Resources Information Center

    McCormack, Abby; Griffiths, Mark D.

    2012-01-01

    The popularity of poker (and in particular online poker) has increasingly grown worldwide in recent years. This increase in the popularity of poker has led to the increased incidence of the "professional poker player". However, very little empirical research has been carried out into this relatively new group of gamblers. The aim was to determine…

  18. Relations between basic and specific motor abilities and player quality of young basketball players.

    PubMed

    Marić, Kristijan; Katić, Ratko; Jelicić, Mario

    2013-05-01

    Subjects from 5 first league clubs from Herzegovina were tested with the purpose of determining the relations of basic and specific motor abilities, as well as the effect of specific abilities on player efficiency in young basketball players (cadets). A battery of 12 tests assessing basic motor abilities and 5 specific tests assessing basketball efficiency were used on a sample of 83 basketball players. Two significant canonical correlations, i.e. linear combinations explained the relation between the set of twelve variables of basic motor space and five variables of situational motor abilities. Underlying the first canonical linear combination is the positive effect of the general motor factor, predominantly defined by jumping explosive power, movement speed of the arms, static strength of the arms and coordination, on specific basketball abilities: movement efficiency, the power of the overarm throw, shooting and passing precision, and the skill of handling the ball. The impact of basic motor abilities of precision and balance on specific abilities of passing and shooting precision and ball handling is underlying the second linear combination. The results of regression correlation analysis between the variable set of specific motor abilities and game efficiency have shown that the ability of ball handling has the largest impact on player quality in basketball cadets, followed by shooting precision and passing precision, and the power of the overarm throw.

  19. Adolescent care

    PubMed Central

    Gilbert, Andrée; Maheux, Brigitte; Frappier, Jean-Yves; Haley, Nancy

    2006-01-01

    OBJECTIVE To investigate how often family physicians see adolescents with mental health problems and how they manage these problems. DESIGN Mailed survey completed anonymously. SETTING Province of Quebec. PARTICIPANTS All 358 French-speaking family physicians who practise primarily in local community health centres (CLSCs), including physicians working in CLSC youth clinics, and 749 French-speaking practitioners randomly selected from private practice. MAIN OUTCOME MEASURES Frequency with which physicians saw adolescents with mental health problems, such as depression, suicidal thoughts, behavioural disorders, substance abuse, attempted suicide, or suicide, during the last year or since they started practice. RESULTS Response rate was 70%. Most physicians reported having seen adolescents with mental health problems during the last year. About 10% of practitioners not working in youth clinics reported seeing adolescents with these disorders at least weekly. Anxiety was the most frequently seen problem. A greater proportion of physicians working in youth clinics reported often seeing adolescents for all the mental health problems examined in this study. Between 8% and 33% of general practitioners not working in youth clinics said they had not seen any adolescents with depression, behavioural disorders, or substance abuse. More than 80% of physicians had seen adolescents who had attempted suicide, and close to 30% had had adolescent patients who committed suicide. CONCLUSION Family physicians play a role in adolescent mental health care. The prevalence of mental health problems seems higher among adolescents who attend youth clinics. Given the high prevalence of these problems during adolescence, we suggest on the basis of our results that screening for these disorders in primary care could be improved. PMID:17279202

  20. Prospective Player-Reported Injuries in Female Youth Fast-Pitch Softball Players

    PubMed Central

    Smith, Matthew V.; Davis, Randi; Brophy, Robert H.; Prather, Heidi; Garbutt, Jane; Wright, Rick W.

    2015-01-01

    Background: There is a scarcity of literature evaluating injuries in youth fast-pitch softball players. Purpose: To perform a descriptive analysis of player-reported injuries in youth fast-pitch softball position players and pitchers during a single select-level season. Study Design: Prospective observation cohort study. Level of Evidence: Level 3. Methods: Ninety-eight athletes (48 pitchers, 50 position players) were followed for a single select fast-pitch softball season. Study participants completed web-based surveys every 3 weeks reporting injuries related to participation in fast-pitch softball. Injury was defined as pain causing cessation of participation in the current game or practice that prevents the player’s return to that session or any pain that causes cessation of a player’s customary participation on the day after the day of onset. Results: The median age of the study participants was 14 years (range, 9-18 years). There were 49 reported injuries in 98 athletes. The average age was 13 years for those not injured and 14 years for those who were injured (P < 0.02). There were 31 injuries that were not related to pitching: 19 occurred in position players and 12 occurred in pitchers; 70% of these injuries were to the lower extremity. The proportion of injuries not related to pitching was significantly greater than the proportion of injuries related to pitching (P < 0.02). Eighteen injuries among the 48 pitchers (38%) were directly attributed to pitching. Among the 18 pitching injuries, 11 (61%) involved the shoulder. The majority (78%) of injuries related to pitching occurred in the first 6 weeks of the season. Conclusion: There was a high incidence of injury in this prospective cohort of youth select-level fast-pitch softball players. Better off-season and preseason conditioning may be a key factor for reducing pitching injuries. Clinical Relevance: Recognition of injury patterns in fast-pitch softball players is critical to developing strategies to

  1. Core executive functions are associated with success in young elite soccer players

    PubMed Central

    Reinebo, Gustaf; Maurex, Liselotte; Ingvar, Martin; Petrovic, Predrag

    2017-01-01

    Physical capacity and coordination cannot alone predict success in team sports such as soccer. Instead, more focus has been directed towards the importance of cognitive abilities, and it has been suggested that executive functions (EF) are fundamentally important for success in soccer. However, executive functions are going through a steep development from adolescence to adulthood. Moreover, more complex EF involving manipulation of information (higher level EF) develop later than simple executive functions such as those linked to simple working memory capacity (Core EF). The link between EF and success in young soccer players is therefore not obvious. In the present study we investigated whether EF are associated with success in soccer in young elite soccer players. We performed tests measuring core EF (a demanding working memory task involving a variable n-back task; dWM) and higher level EF (Design Fluency test; DF). Color-Word Interference Test and Trail Making Test were performed on an exploratory level as they contain a linguistic element. The lower level EF test (dWM) was taken from CogStateSport computerized concussion testing and the higher level EF test (DF) was from Delis-Kaplan Executive Function System test battery (D-KEFS). In a group of young elite soccer players (n = 30; aged 12–19 years) we show that they perform better than the norm in both the dWM (+0.49 SD) and DF (+0.86 SD). Moreover, we could show that both dWM and DF correlate with the number of goals the players perform during the season. The effect was more prominent for dWM (r = 0.437) than for DF (r = 0.349), but strongest for a combined measurement (r = 0.550). The effect was still present when we controlled for intelligence, length and age in a partial correlation analysis. Thus, our study suggests that both core and higher level EF may predict success in soccer also in young players. PMID:28178738

  2. HIP AND KNEE EXTENSOR MOMENTS PREDICT VERTICAL JUMP HEIGHT IN ADOLESCENT GIRLS

    PubMed Central

    FORD, KEVIN R.; MYER, GREGORY D.; BRENT, JENSEN L.; HEWETT, TIMOTHY E.

    2014-01-01

    Biomechanical factors, such as hip and knee extensor moments, related to drop jump (DJ) performance have not been investigated in adolescent girls. The purpose of this study was to determine the key independent biomechanical variables that predict overall vertical jump performance in adolescent girls. Sixteen high school adolescent girls from club–sponsored and high school–sponsored volleyball teams performed DJ at 3 different drop heights (15, 30, and 45 cm). A motion analysis system consisting of 10 digital cameras and a force platform was used to calculate vertical jump height, joint angles, and joint moments during the tasks. A multiple linear regression was used to determine the biomechanical parameters that were best predictive of vertical jump height at each box drop distance. The 2 predictor variables in all 3 models were knee and hip extensor moments. The models predicted 82.9, 81.9, and 88% of the vertical jump height variance in the 15, 30, and 45 cm trials, respectively. The results of the investigation indicate that knee and hip joint moments are the main contributors to vertical jump height during the DJ in adolescent girls. Strength and conditioning specialists attempting to improve vertical jump performance should target power and strength training to the hip and knee extensors in their athletes. PMID:19528842

  3. Hip and knee extensor moments predict vertical jump height in adolescent girls.

    PubMed

    Ford, Kevin R; Myer, Gregory D; Brent, Jensen L; Hewett, Timothy E

    2009-07-01

    Biomechanical factors, such as hip and knee extensor moments, related to drop jump (DJ) performance have not been investigated in adolescent girls. The purpose of this study was to determine the key independent biomechanical variables that predict overall vertical jump performance in adolescent girls. Sixteen high school adolescent girls from club-sponsored and high school-sponsored volleyball teams performed DJ at 3 different drop heights (15, 30, and 45 cm). A motion analysis system consisting of 10 digital cameras and a force platform was used to calculate vertical jump height, joint angles, and joint moments during the tasks. A multiple linear regression was used to determine the biomechanical parameters that were best predictive of vertical jump height at each box drop distance. The 2 predictor variables in all 3 models were knee and hip extensor moments. The models predicted 82.9, 81.9, and 88% of the vertical jump height variance in the 15, 30, and 45 cm trials, respectively. The results of the investigation indicate that knee and hip joint moments are the main contributors to vertical jump height during the DJ in adolescent girls. Strength and conditioning specialists attempting to improve vertical jump performance should target power and strength training to the hip and knee extensors in their athletes.

  4. Competitive Sport Involvement and Substance Use among Adolescents: A Nationwide Study

    PubMed Central

    Veliz, Philip Todd; Boyd, Carol J.; McCabe, Sean Esteban

    2015-01-01

    Background The empirical research examining the impact of sports participation on alcohol and other drug use has produced mixed results. Part of this problem may be the result of how different types of sports participation create different experiences that shape certain types of behaviors that either facilitate or deter substance use. Objectives We examined the association between different types of competitive sports participation and substance use among a nationally representative sample of adolescents. Methods Two recent cross-sections from the Monitoring the Future were merged to capture a large subsection of adolescents who participate in either high-contact sports (football, wrestling, hockey and lacrosse), semi-contact sports (baseball, basketball, field hockey and soccer), and non-contact sports (cross-country, gymnastics, swimming, tennis, track, and volleyball). Results Multivariate analyses revealed that adolescents who participated in high-contact sports had higher odds of using substances during the past 30 days and initiating substance use at early ages. Further, adolescents who participated in non-contact sports had lower odds to indicate smoking cigarettes and marijuana during the past 30 days. Conclusions Parents, educators, and policy makers need to consider that some sporting contexts may be a catalyst to engage in risky behaviors like substance use. PMID:25290659

  5. Adolescent Literacy

    ERIC Educational Resources Information Center

    Ippolito, Jacy, Ed.; Steele, Jennifer L., Ed.; Samson, Jennifer F., Ed.

    2012-01-01

    "Adolescent Literacy" initially appeared as a special issue of the "Harvard Educational Review". It explores key issues and debates in the adolescent literacy crisis, the popular use of cognitive strategies, and disciplinary and content-area literacy. Also examined are alternative forms of literacy, afterschool interventions, new instruction…

  6. Adolescent Abuse.

    ERIC Educational Resources Information Center

    Foreman, Susan; Seligman, Linda

    1983-01-01

    Discusses legal and developmental aspects of adolescent abuse, as distinguished from child abuse. The role of the school counselor in identifying and counseling abused adolescents and their families is discussed and several forms of intervention and support services are described. (JAC)

  7. Adolescent Loneliness.

    ERIC Educational Resources Information Center

    Goldenberg, Sheila

    Research has suggested that the incidence of loneliness peaks at adolescence and decreases with age. Changes in the determinants of loneliness during adolescence were investigated for grade 8, grade 11, and university students. Subjects (N=410) completed a written questionnaire which included ten items from the UCLA Loneliness Scale, the…

  8. Adolescent Turmoil.

    ERIC Educational Resources Information Center

    Offer, Daniel

    1982-01-01

    Examines recent empirical evidence to test theories postulated in separate works by G. Stanley Hall and Anna Freud that adolescents must experience psychological turbulence in the transition to adulthood. Concludes that turmoil is no longer a necessary condition of adolescence and that those who do experience it need psychiatric attention.…

  9. Prevalence of Vitamin D Insufficiency in Professional Hockey Players

    PubMed Central

    Mehran, Nima; Schulz, Brian M.; Neri, Brian R.; Robertson, William J.; Limpisvasti, Orr

    2016-01-01

    Background: Vitamin D is a fat-soluble hormone that plays a role in bone health, muscle function, and athletic performance. Studies have shown that low levels of vitamin D can lead to slower muscle recovery and function, increased rates of stress fractures, and even poorer athletic performance. Insufficient vitamin D levels have been demonstrated in professional basketball and football players, however, there have been no studies to date reviewing vitamin D insufficiency in professional hockey players. Purpose/Hypothesis: The purpose of this study was to perform a cross-sectional review to determine the prevalence of vitamin D deficiency and insufficiency in professional hockey players. The hypothesis was that there would be a high percentage of players with vitamin D insufficiency. Study Design: Cross-sectional study; Level of evidence, 3. Methods: The preseason serum 25-hydroxy (OH) vitamin D laboratory test results of 105 professional hockey players were retrospectively reviewed. All players on 3 National Hockey League (NHL) teams were included. Player parameters evaluated included age, height, weight, body mass index, and 25(OH) vitamin D level. Players were divided into 4 groups based on serum vitamin D levels: deficient (<20 ng/mL), insufficient (20-31.9 ng/mL), sufficient (≥32 ng/mL), and ideal (≥40 ng/mL). Descriptive statistics were performed, in addition to 2-group and 3-group comparisons. Results: The average 25(OH) vitamin D level of 105 players was 45.8 ± 13.7 ng/mL (range, 24-108 ng/mL). No players in the study were considered deficient. A total of 14 players (13.3%) were considered insufficient, while 91 players (86.7%) were considered sufficient. However, only 68 players (64.8%) were considered ideal. When comparing groups, athletes with sufficient vitamin D levels were older than athletes with insufficient vitamin D levels (25.9 vs 23.1 years; P = .018). All other player parameters demonstrated no significant difference between groups

  10. Sex-specific differences in injury types among basketball players

    PubMed Central

    Ito, Eri; Iwamoto, Jun; Azuma, Koichiro; Matsumoto, Hideo

    2015-01-01

    The purpose of the present study was to investigate sex-specific differences in injury types among basketball players. According to our database, during the 20-year period between October 1991 and June 2011, 1,219 basketball players (640 males and 579 females) consulted our sports medicine clinic; in total, 1,414 injuries in basketball players (729 injuries in males and 685 injuries in females) were recorded. The mean age of patients was 19.6 years. The most common injury site was the knee, followed by the foot and ankle, lower back, and upper extremities. There was a higher proportion of female players presenting with a knee injury, compared with male players (50.4% vs 41.7%), and a lower proportion of female players presenting with an upper extremity injury (5.1% vs 9.7%). The proportion of anterior cruciate ligament injury in the 10–19-year-old age group was higher among female players than among male players (45.9% vs 22.1%), while the proportions of Osgood–Schlatter disease in the 10–19-year-old age group and jumper’s knee (patellar and femoral tendinopathy) in the 20–29-year-old age group were higher among male players than among female players (12.5% vs 1.8% and 14.6% vs 3.7%, respectively). However, the proportions of other injuries did not differ significantly between male and female players. The present observational study, which was performed using a retrospective case-series design, showed the existence of sex-specific differences in knee injuries sustained while participating in basketball. PMID:25565908

  11. N-player quantum games in an EPR setting.

    PubMed

    Chappell, James M; Iqbal, Azhar; Abbott, Derek

    2012-01-01

    The N-player quantum games are analyzed that use an Einstein-Podolsky-Rosen (EPR) experiment, as the underlying physical setup. In this setup, a player's strategies are not unitary transformations as in alternate quantum game-theoretic frameworks, but a classical choice between two directions along which spin or polarization measurements are made. The players' strategies thus remain identical to their strategies in the mixed-strategy version of the classical game. In the EPR setting the quantum game reduces itself to the corresponding classical game when the shared quantum state reaches zero entanglement. We find the relations for the probability distribution for N-qubit GHZ and W-type states, subject to general measurement directions, from which the expressions for the players' payoffs and mixed Nash equilibrium are determined. Players' N x N payoff matrices are then defined using linear functions so that common two-player games can be easily extended to the N-player case and permit analytic expressions for the Nash equilibrium. As a specific example, we solve the Prisoners' Dilemma game for general N ≥ 2. We find a new property for the game that for an even number of players the payoffs at the Nash equilibrium are equal, whereas for an odd number of players the cooperating players receive higher payoffs. By dispensing with the standard unitary transformations on state vectors in Hilbert space and using instead rotors and multivectors, based on Clifford's geometric algebra (GA), it is shown how the N-player case becomes tractable. The new mathematical approach presented here has wide implications in the areas of quantum information and quantum complexity, as it opens up a powerful way to tractably analyze N-partite qubit interactions.

  12. Scapula Kinematics of Youth Baseball Players

    PubMed Central

    Oliver, Gretchen; Weimar, Wendi

    2015-01-01

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly. PMID:26839605

  13. Knee alignment in professional tennis players.

    PubMed

    Maquirriain, Javier

    2002-01-01

    This study determined lower-limb alignment and knee geometry in professional tennis players and compared the data with those from nonathletic individuals. Twenty-four radiographs from 12 asymptomatic players (mean age: 23.4+/-3.8 years) were prospectively studied. The three angles most useful for describing limb alignment and knee geometry in the coronal plane were measured: hip-knee-ankle, condylar-hip, and plateau-ankle. The condylar-plateau angle, frontal foot rotation angle, and the relationship between the mechanical axis and tibial plateau also were calculated. Varus limb alignment was predominant and the mechanical axis passed medially through the knee center; there was increased valgus inclination of the distal femur, varus angulation of the tibial plateau, near parallel alignment of the joint, and exaggerated external foot rotation. Hip-knee-ankle, condylar-hip, plateau-ankle, and frontal foot rotation angles were significantly different (P<.05, two-tailed t test) from previously reported angles of nonathletic individuals. Variations, probably due to repetitive dynamic demands imposed on lower limbs from an early age, seem to involve both femoral condyles and proximal tibial metaphyses, maintaining normal parallel joint alignment.

  14. Scapula Kinematics of Youth Baseball Players.

    PubMed

    Oliver, Gretchen; Weimar, Wendi

    2015-12-22

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  15. Decision-Making and Thought Processes among Poker Players

    ERIC Educational Resources Information Center

    St. Germain, Joseph; Tenenbaum, Gershon

    2011-01-01

    This study was aimed at delineating decision-making and thought processing among poker players who vary in skill-level. Forty-five participants, 15 in each group, comprised expert, intermediate, and novice poker players. They completed the Computer Poker Simulation Task (CPST) comprised of 60 hands of No-Limit Texas Hold 'Em. During the CPST, they…

  16. Gender Differences in Coping among Elite Table Tennis Players

    ERIC Educational Resources Information Center

    Kirimoglu, Huseyin

    2011-01-01

    The current study aims to investigate the explanatory power of social support and coping in relation to a competitive sport event between male and female table tennis players. 246 university students table tennis players (120 men and 126 women) from different region and part of Turkey were invited to participate in a survey study included the…

  17. Space-Derived Transparency: Players, Policies, Implications, and Synergies

    DTIC Science & Technology

    2001-06-01

    Dr. Florini�s idealistic definition, transparency today is at best a mix of � legislated � voluntary and involuntary disclosure by states, private...SPACE-DERIVED TRANSPARENCY : PLAYERS, POLICIES, IMPLICATIONS, AND SYNERGIES BY C. J. KINNAN A THESIS PRESENTED TO THE...to) - Title and Subtitle Space-Derived Transparency : Players, Policies, Implicatons, and Synergies Contract Number Grant Number Program Element

  18. Differences in Soccer Kick Kinematics between Blind Players and Controls

    ERIC Educational Resources Information Center

    Giagazoglou, Paraskevi; Katis, Athanasios; Kellis, Eleftherios; Natsikas, Christos

    2011-01-01

    The purpose of the current study was to examine the kinematic differences during instep soccer kicks between players who were blind and sighted controls. Eleven male soccer players who were blind and nine male sighted performed instep kicks under static and dynamic conditions. The results indicated significantly higher (p less than 0.05) ball…

  19. The Mental Skills Training of University Soccer Players

    ERIC Educational Resources Information Center

    Sadeghi, Hassan; Omar-Fauzee, Mohd-Sofian; Jamalis, Marjohan; Ab-Latif, Rozita; Cheric, Majid Chahrdah

    2010-01-01

    The purpose of this study is to identify the kind of mental skills training needed most by the university soccer players. Eight male university football players (aged 25 to 36) from one large university in Kuala Lumpur agreed to participate in this study. On average, they have 10 years of playing experience. All of them have signed the informed…

  20. Relative risk for concussions in young female soccer players.

    PubMed

    Strand, Sarah; Lechuga, David; Zachariah, Thomas; Beaulieu, Kathryn

    2015-01-01

    The objective of this study was to determine the relative risk and reported symptoms of concussions in 11- to 13-year-old, female soccer players. For this, a survey to compare the reported incidence of concussion in age-matched female soccer players to nonsoccer players was performed. The survey included 342 girls between the ages of 11 and 13: 195 were involved in an organized soccer team and 147 were not involved in organized soccer but were allowed to participate in any other sport or activity. A total of 94 of the 195 soccer players, or 48%, reported at least one symptom consistent with a concussion. The most prevalent symptom for these girls was headache (84%). A total of 34 of the 147 nonsoccer players, or 23%, reported at least one symptom consistent with a concussion in the previous six months. These results determined that the relative risk of probable concussions among 11- to 13-year-old, female soccer players is 2.09 (p < .001, α = .05, CI = 95%). This demonstrates that the relative risk of probable concussions in young female soccer players is significantly higher than in a control group of nonsoccer players of the same sex and age.

  1. Labor Market Structure and Salary Determination among Professional Basketball Players.

    ERIC Educational Resources Information Center

    Wallace, Michael

    1988-01-01

    The author investigates the labor market structure and determinants of salaries for professional basketball players. An expanded version of the resource perspective is used. A three-tiered model of labor market segmentation is revealed for professional basketball players, but other variables also are important in salary determination. (Author/CH)

  2. Stages of Adolescence

    MedlinePlus

    ... Español Text Size Email Print Share Stages of Adolescence Page Content Article Body Adolescence, these years from puberty to adulthood, may be roughly divided into three stages: early adolescence, generally ages eleven to fourteen; middle adolescence, ages ...

  3. 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; Weakley, Jonathon J S; Till, Kevin

    2016-08-18

    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, U20). The physical demands were measured using microsensor-based technology and analysed 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 per minute (accumulated accelerations from the three axes of movement) and PlayerLoad slow per minute (accumulated accelerations from the three 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 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 PlayerLoad 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.

  4. National survey of spinal injuries in hockey players.

    PubMed Central

    Tator, C. H.; Edmonds, V. E.

    1984-01-01

    There has been an alarming increase in the number of spinal injuries in hockey players. Between 1976 and 1983, 42 were reported to the Committee on Prevention of Spinal Injuries due to Hockey. The median age of the injured players was 17 years. Of the 42 players 28 had spinal cord injuries, and 17 of them had complete paralysis below the vertebral level of the injury. Strikes from behind and collisions with the boards were common mechanisms of injury. Many of the players had suffered a burst fracture of the cervical spine following a blow to the top of the helmet when the neck was slightly flexed. The committee studied a number of possible etiologic factors and made several recommendations regarding prevention. League officials, coaches, players and equipment manufacturers can all play a role in prevention. Images Fig. 1 Fig. 2 PMID:6704840

  5. Adult and Adolescent Social Reciprocity: Experimental Data from the Trust Game

    ERIC Educational Resources Information Center

    Belli, Stefano R.; Rogers, Robert D.; Lau, Jennifer Y. F.

    2012-01-01

    Twenty-four adults (aged 19-35) and 27 adolescents (aged 13-14) played as "Trustee" in an iterated Trust Game against a pre-programmed set of "Investor" moves, said to belong to an unknown co-player. Trustee behaviour was examined first in response to normative Investor cooperation, and then in response to a period of social rupture caused by…

  6. The Pizzagame: A virtual public goods game to assess cooperative behavior in children and adolescents.

    PubMed

    Keil, Jan; Michel, Andrea; Sticca, Fabio; Leipold, Kristina; Klein, Annette M; Sierau, Susan; von Klitzing, Kai; White, Lars O

    2016-09-07

    Social dilemmas are characterized by conflicts between immediate self-interest and long-term collective goals. Although such conflicts lie at the heart of various challenging social interactions, we know little about how cooperation in these situations develops. To extend work on social dilemmas to child and adolescent samples, we developed an age-appropriate computer task (the Pizzagame) with the structural features of a public goods game (PGG). We administered the Pizzagame to a sample of 191 children 9 to 16 years of age. Subjects were led to believe they were playing the game over the Internet with three sets of two same-aged, same-sex co-players. In fact, the co-players were computer-generated and programmed to expose children to three consecutive conditions: (1) a cooperative strategy, (2) a selfish strategy, and (3) divergent cooperative-selfish strategies. Supporting the validity of the Pizzagame, our results revealed that children and adolescents displayed conditional cooperation, such that their contributions rose with the increasing cooperativeness of their co-players. Age and gender did not influence children and adolescents' cooperative behavior within each condition. However, older children adapted their behavior more flexibly between conditions to parallel the strategies of their co-players. These results support the utility of the Pizzagame as a feasible, reliable, and valid instrument for assessing and quantifying child and adolescent cooperative behavior. Moreover, these findings extend previous work showing that age influences cooperative behavior in the PGG.

  7. "No Fear Comes": Adolescent Girls, Ice Hockey, and the Embodiment of Gender.

    ERIC Educational Resources Information Center

    Theberge, Nancy

    2003-01-01

    Examined the relationship between gender, physicality, and embodiment among Canadian adolescent girls who played ice hockey. Interview data indicated that the girls emphasized the importance of being aggressive (fearless in use of the body). Players understood that contrasts between men's hockey (more physical and aggressive) and women's hockey…

  8. The Contribution of Organized Youth Sport to Antisocial and Prosocial Behavior in Adolescent Athletes

    ERIC Educational Resources Information Center

    Rutten, Esther A.; Stams, Geert Jan J. M.; Biesta, Gert J. J.; Schuengel, Carlo; Dirks, Evelien; Hoeksma, Jan B.

    2007-01-01

    In this study, we investigated the contribution of organized youth sport to antisocial and prosocial behavior in adolescent athletes. The sample consisted of N = 260 male and female soccer players and competitive swimmers, 12 to 18 years of age. Multilevel regression analysis revealed that 8% of the variance in antisocial behavior and 7% of the…

  9. The relationship between peak height velocity and physical performance in youth soccer players.

    PubMed

    Philippaerts, Renaat M; Vaeyens, Roel; Janssens, Melissa; Van Renterghem, Bart; Matthys, Dirk; Craen, Rita; Bourgois, Jan; Vrijens, Jacques; Beunen, Guston; Malina, Robert M

    2006-03-01

    Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time.

  10. Influence of players' physique on rugby football injuries.

    PubMed Central

    Lee, A J; Myers, J L; Garraway, W M

    1997-01-01

    OBJECTIVES: To determine whether there is an association between a player's physique and injuries incurred while playing rugby football. METHODS: A cohort study was carried out involving all senior rugby clubs in the Scottish Borders during the 1993-1994 rugby season. Somatotype estimates were determined for 1152 (95%) of the 1216 eligible players. Body mass index (BMI), chest to waist ratio, and the ponderal index (PI) were used to classify players' physique as endomorphic (obese), mesomorphic (muscular), and ectomorphic (linear). RESULTS: A strong association was found between physique and age (chi 2 test: chi 2 = 317.2, df = 10, P < 0.0001). More younger players were ectomorphs. Older players were more often endomorphic. The physiques of forwards and backs were significantly different (chi 2 test: chi 2 = 58.6, df = 2, P < 0.0001), with forwards being of a heavier build than three-quarters, even after adjustment for age. Endomorphic players were more likely than ectomorphs to be injured in a match after adjustment for age (age-adjusted mean BMI for players who were injured in a match was 25.4 compared with 24.6 for players who were not injured in a match, P < 0.0001; adjusted chest to waist ratio means were 1.136 and 1.125 respectively, P = 0.0307; adjusted PI means were 0.414 and 0.417 respectively, P = 0.0056). Increased risk of injury may occur when players play out of position, since one fifth of all injuries occurred in this circumstance. CONCLUSIONS: Further research needs to be conducted using a more objective method of measuring somatotype on a further cohort of players so that the risk of injury for different body types can be examined more closely and related to other potential confounding factors. The level of increased risk for individuals playing out of their usual playing position needs to be established with a greater degree of certainty. PMID:9192128

  11. Coach/player relationships in tennis.

    PubMed

    Prapavessis, H; Gordon, S

    1991-09-01

    The present study examined the variables that predict coach/athlete compatibility. Compatibility among a sample of 52 elite tennis coach/player dyads was assessed using a sport adapted version of Schutz's (1966) Fundamental Interpersonal Relations Orientation-Behaviour (FIRO-B), a sport adapted version of Fiedler's (1967) Least Preferred Co-worker scale (LPC), and Chelladurai and Saleh's (1980) Leadership Scale for Sport (LSS). Self-ratings of the quality of the interaction were obtained from both coach and athlete. Multiple-regression analyses using self-rating scores as the dependent measure were carried out to determine which variables best predicted the degree of compatibility. The sole inventory that significantly predicted compatibility was the LSS. More specifically, the discrepancy between the athlete's preferences and perceptions on the autocratic dimension was the best predictor. Implications for tennis coaches and recommendations for future research in this area are discussed.

  12. Histone variants: emerging players in cancer biology

    PubMed Central

    Vardabasso, Chiara; Hasson, Dan; Ratnakumar, Kajan; Chung, Chi-Yeh; Duarte, Luis F.

    2014-01-01

    Histone variants are key players in shaping chromatin structure, and, thus, in regulating fundamental cellular processes such as chromosome segregation and gene expression. Emerging evidence points towards a role for histone variants in contributing to tumor progression, and, recently, the first cancer-associated mutation in a histone variant-encoding gene was reported. In addition, genetic alterations of the histone chaperones that specifically regulate chromatin incorporation of histone variants are rapidly being uncovered in numerous cancers. Collectively, these findings implicate histone variants as potential drivers of cancer initiation and/or progression, and, therefore, targeting histone deposition or the chromatin remodeling machinery may be of therapeutic value. Here, we review the mammalian histone variants of the H2A and H3 families in their respective cellular functions, and their involvement in tumor biology. PMID:23652611

  13. Musculoskeletal profile of male collegiate soccer players.

    PubMed

    Agre, J C; Baxter, T L

    1987-03-01

    Twenty-five collegiate soccer players were evaluated for lower extremity flexibility and muscle strength at the end of preseason training and before the onset of the collegiate soccer season on two successive seasons. The purpose of the evaluation was to determine whether symmetry was present in their legs and whether deficits in flexibility or strength would affect the susceptibility to hamstring or groin muscle strain injuries. The mean (+/- SE) flexibility of the dominant leg for hip abduction was 41 degrees +/- 1.2 degree; for hip flexion, 76 degrees +/- 1.9 degree; for hip extension, 174 degrees +/- 0.7 degree; and for ankle dorsiflexion, 33 degrees +/- 1.3 degree. The mean (+/- SE) isokinetic torque of the dominant leg (tested at 30 degrees per second) for knee extension was 214 +/- 8 newton meters and for flexion was 128 +/- 4 newton meters, while isometric strength for hip flexion was 315 +/- 8 newtons and for ankle plantar flexion was 1721 +/- 58 newtons. No significant differences were found between the dominant and nondominant legs in flexibility or strength. During this study no hamstring or groin strain injuries occurred. The lack of leg muscle strain injuries appeared to be directly related to the initiation of a controlled warmup and stretching program and underlines the importance of this in injury prevention. Interestingly, more than 50% (13 of 25) of the players were found to have significant deficits in one or more specific muscle groups. Two athletes sustained low back strain injuries and one athlete had a knee sprain injury.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. University Football Players, Postural Stability, and Concussions.

    PubMed

    Graves, Barbara Sue

    2016-02-01

    Concussion in football athletes is certainly more prevalent and has potentially serious outcomes. With current concerns and increasing return-to-play issues, additional assessment focus is needed. Division 1 college football athletes, from 18 to 20.9 years (n = 177; age, 19.7 ± 1.2 years; height, 182.3 ± 4.5 cm; weight, 97.3 ± 10.6 kg), before fall practice, over a period of 3 years, underwent baseline postural stability testing (sensory organization test [SOT], NeuroCom). Individuals, who were diagnosed with a concussion (headache, dizziness, fatigue, confusion, or loss of consciousness) during practice or actual competition (n = 15; age, 18.9 ± 0.9 years; height, 181.8 ± 2.5 cm; weight, 86.6 ± 3.6 kg), underwent serial evaluation after injury and 24 hours after concussion. As soon as the player was considered asymptomatic, the test was completed on the first and 14th day. A control group of noninjured male athletes (n = 15; age, 19.1 ± 0.4 years; height, 178.2 ± 3.2 cm; weight, 78.6 ± 2.1 kg) were tested for the same time frame. This particular study was only one part of the total evaluation conducted for the concussed athlete's return to play. Results indicated that the concussion group had a statistically significant (p = 0.037) change from their baseline SOT score and the control group (p = 0.025). This change remained significant until day 14 of posttesting. These data indicate that the SOT, when available, may be a positive additional assessment of concussed college-aged football players. Professionals, when dealing with concussion in competitive sports, do need to continue to work together, but awareness of SOT assessments may also contribute to the return-to-play decisions.

  15. Performance demands of professional male tennis players

    PubMed Central

    Johnson, C D

    2006-01-01

    Objective To quantify the performance demands in professional male tennis. Methods Games from three grand slam tournaments were analysed by an elite tennis player from video recordings. Game related data were collected on 22 players (French Open, 8 (186 games); Wimbledon, 11 (206 games); US Open, 9 (224 games)). Total number of strokes per game was quantified separately for service and return games. Strokes were categorised by type and designated as forehand or backhand. Differences in the types of strokes in a game were analysed using one factor (type of stroke) repeated measures analysis of variance. Differences in total strokes and stroke distributions between playing surfaces were analysed by analysis of variance (surface type) with Tukey's post hoc pairwise comparisons. Results For service games there were more serves per game than any other type of stroke (p<0.001), with topspin forehand and topspin backhand the only other strokes averaging more than one per service game. For return games there were more forehand and backhand returns and topspin forehands and backhands than other types of stroke (p<0.01). Total number of strokes per game was greater in the French Open than Wimbledon (p<0.01), with more topspin forehands (p<0.01) and more topspin backhands (p<0.01). Total strokes per game in the US Open were not different from the other two tournaments. Conclusions The serve was the predominant stroke accounting for 45% (French Open) to 60% (Wimbledon) of strokes during service games. The greater number of strokes per game on clay v grass may contribute to earlier fatigue. PMID:16864564

  16. Cervical range of motion and proprioception in rugby players versus non-rugby players.

    PubMed

    Lark, Sally D; McCarthy, Peter W

    2007-06-01

    In this study, we examined the effects of number of years of playing rugby on neck function. Active cervical spine range of motion and proprioception were assessed in 14 non-rugby-playing but trained sportsmen (mean age 28 years, s = 7) and 46 rugby players (26 rugby forwards: mean age 26 years, s = 5; mean years played 14 years; 20 backs: mean age 24 years, s = 5; mean years played 14 years). Active cervical range of motion in flexion, extension, left and right lateral flexion, plus left and right rotation were measured using a cervical range of motion device. The ability to reposition the head in a central position with eyes closed was taken as a measure of proprioception. Results show that rugby forwards generally had the least active cervical range of motion, particularly neck extension (forwards, 43 degrees ; backs, 55 degrees ; controls, 58 degrees ), with the decrement correlating with the number of years played. In addition, repositioning was significantly worse in rugby players after neck extension than non-rugby players (6 degrees vs. 3 degrees ). The active cervical range of motion of rugby forwards is similar to that of whiplash patients, suggesting that participation in rugby can have an effect on neck range of motion that is equivalent to chronic disability. Reduced active cervical range of motion could also increase the likelihood of injury and exacerbate age-related neck problems.

  17. Adolescent Depression

    PubMed Central

    Cook, Mary N.; Peterson, John; Sheldon, Christopher

    2009-01-01

    Depression in adolescence and adulthood is common, afflicting up to 20 percent of these populations. It represents a significant public health concern and is associated with considerable suffering and functional impairment. Adolescent-onset depression tends to be a particularly malignant and recalcitrant condition, increasing the likelihood of recurrence and chronicity in adulthood. Clinical presentations for various medical and psychiatric conditions, as well as reactions to psychosocial stressors, can mimic or confound the picture of depression in adolescents. Therefore, careful assessment and differential diagnosis is essential. Effective treatments, both pharmacological and psychosocial in nature, exist, and so early detection and intervention is paramount. This article presents an overview of optimal prevention, assessment, and clinical decision-making strategies for managing depression in adolescents. PMID:19855857

  18. Adolescent sexuality.

    PubMed

    Grant, L M; Demetriou, E

    1988-12-01

    The consequences of adolescent sexual behavior are an enormous burden both for the adolescent and society. The problem is not that teens are sexually active but rather that they have little preparation and guidance in developing responsible sexual behavior. Developmentally, adolescents reach physical maturity before they are cognitively able to appreciate the consequences of their behavior. A teenager's primary source of information regarding sexuality is his or her peer group, all of whom are experiencing and reinforcing the same behaviors. The family, the major socializer of other behaviors, is not as powerful a force in shaping responsible sexual behavior because of parental discomfort with sex education and sexual discussions. This is the result of a social milieu in which sex is frequently portrayed but rarely linked with responsible behavior or accurate, nonjudgmental information. The pediatric practitioner is in an ideal position to intervene in these dynamics. In the office, the practitioner can provide accurate sexual information to both parents and adolescents, support parental-child communication on sexual issues, and provide appropriate services or referral. In the community, the practitioner can advocate for school-based sex education as well as act as an information resource. Finally, the practitioner can advocate for the health care needs for adolescents on a national level, supporting legislation that provides adolescents with information and access to services necessary to make responsible sexual decisions.

  19. Nutrition and hydration concerns of the female football player.

    PubMed

    Maughan, Ronald J; Shirreffs, Susan M

    2007-08-01

    There is little information on the nutritional habits of female football players at any level of the game. There is also a shortage of information on the nutrition and hydration strategies that players should adopt. In general, differences in nutritional needs between males and females are smaller than differences between individuals, so that principles developed for male players also apply to women. There is a need to address energy balance and body composition: prolonged energy deficits cannot be sustained without harm to health and performance. Published reports show mean carbohydrate intakes for female players of about 5 g/kg/day, and this seems to be too low to sustain consistent intensive training. The timing of protein intake may be as important as the amounts consumed, provided that the total intake is adequate. Dehydration adversely affects skill and stamina in women as it does in men, so an individualised hydration strategy should be developed. The prevalence of iron deficiency in women generally is high, but it seems to be alarmingly high in female players. All players should adopt dietary habits that ensure adequate iron intake. Football training seems to increase bone mass in the weight-bearing limbs, with positive implications for bone health in later life, but some players may be at risk from inadequate calcium dietary intake.

  20. Throwing speed and accuracy in baseball and cricket players.

    PubMed

    Freeston, Jonathan; Rooney, Kieron

    2014-06-01

    Throwing speed and accuracy are both critical to sports performance but cannot be optimized simultaneously. This speed-accuracy trade-off (SATO) is evident across a number of throwing groups but remains poorly understood. The goal was to describe the SATO in baseball and cricket players and determine the speed that optimizes accuracy. 20 grade-level baseball and cricket players performed 10 throws at 80% and 100% of maximal throwing speed (MTS) toward a cricket stump. Baseball players then performed a further 10 throws at 70%, 80%, 90%, and 100% of MTS toward a circular target. Baseball players threw faster with greater accuracy than cricket players at both speeds. Both groups demonstrated a significant SATO as vertical error increased with increases in speed; the trade-off was worse for cricketers than baseball players. Accuracy was optimized at 70% of MTS for baseballers. Throwing athletes should decrease speed when accuracy is critical. Cricket players could adopt baseball-training practices to improve throwing performance.

  1. Measurement of head impacts in youth ice hockey players.

    PubMed

    Reed, N; Taha, T; Keightley, M; Duggan, C; McAuliffe, J; Cubos, J; Baker, J; Faught, B; McPherson, M; Montelpare, W

    2010-11-01

    Despite growing interest in the biomechanical mechanisms of sports-related concussion, ice hockey and the youth sport population has not been studied extensively. The purpose of this pilot study was: 1) to describe the biomechanical measures of head impacts in youth minor ice hockey players; and, 2) to investigate the influence of player and game characteristics on the number and magnitude of head impacts. Data was collected from 13 players from a single competitive Bantam boy's (ages 13-14 years) AAA ice hockey team using telemetric accelerometers implanted within the players' helmets at 27 ice hockey games. The average linear acceleration, rotational acceleration, Gadd Severity Index and Head Injury Criterion of head impacts were recorded. A significantly higher number of head impacts per player per game were found for wingers when compared to centre and defense player positions (df=355, t=3.087, p=0.00218) and for tournament games when compared to regular season and playoff games (df=355, t=2.641, p=0.086). A significant difference in rotational acceleration according to player position (F2,1812=4.9551, p=0.0071) was found. This study is an initial step towards a greater understanding of head impacts in youth ice hockey.

  2. Physical performance of elite and subelite Spanish female futsal players

    PubMed Central

    Rubio-Arias, JA; Carrasco-Poyatos, M; Alcaraz, PE

    2016-01-01

    The aim of this study was to determine the parameters distinguishing top female futsal players from lower level players. Twenty-seven female futsal players participated in the study, composed of professional first division (elite; n = 15) players and semi-professional second division players (sub-elite; n = 14). Active and passive straight leg raise tests, isokinetic strength of the knee extensor and flexor muscles at 60° · s-1 angular velocity, squat and counter movement jumps, 30 m sprint, 30 m agility, repeated sprint ability test and maximum ball speed during shooting were measured. The elite players were more agile and kicked harder than sub-elite players in maximum ball speed during the shooting test (P ≤ 0.05). However, no significant differences between teams were observed in active and passive hamstring flexibility, jumping ability, repeated sprint ability test, 30 m sprint time, H/Q ratio and absolute and relative torque from 60° · s-1 angular velocity. Based on these findings we conclude that agility and maximum ball speed during shooting may be important determinant factors of Spanish female futsal actions and could distinguish ability at high-level games. PMID:27601786

  3. Physical and performance characteristics of successful high school football players.

    PubMed

    Williford, H N; Kirkpatrick, J; Scharff-Olson, M; Blessing, D L; Wang, N Z

    1994-01-01

    The purpose of this investigation was to determine the performance and physiologic characteristics of a "successful" American high school football team, and to compare the present values with values reported for other groups of high school, college, and professional players. For descriptive purposes, players were divided into two groups: backs (N = 8) and linemen (N = 10). Maximal aerobic power (VO2max) was determined from a maximal treadmill test, and body composition was evaluated by hydrostatic weighing. Maximal strength values were evaluated by one-repetition maximum bench press and squat test; the sit-and-reach test was used to measure flexibility. Speed and power were evaluated by a vertical jump and a 36.6-meter sprint. Results indicate that compared with other groups of college and professional players, as the level of competition increases so do height, weight, and fat-free weight of the players. Similar maximum oxygen consumption values were found for the present group when compared with other groups of these players. From the strength and power standpoint, football players at all levels are becoming stronger. Incorporation of strength training programs has greatly improved strength and performance profiles of football players at all levels of competition.

  4. Active tuning of stroke-induced vibrations by tennis players.

    PubMed

    Chadefaux, Delphine; Rao, Guillaume; Androuet, Philippe; Berton, Eric; Vigouroux, Laurent

    2016-09-06

    This paper investigates how tennis players control stroke-induced vibration. Its aim is to characterise how a tennis player deals with entering vibration waves or how he/she has the ability to finely adjust them. A specific experimental procedure was designed, based on simultaneously collecting sets of kinematic, vibration and electromyographic data during forehand strokes using various commercial rackets and stroke intensities. Using 14 expert players, a wide range of excitations at spectral and temporal levels were investigated. Energetic and spectral descriptors of stroke-induced vibration occurring at the racket handle and at the player's wrist and elbow were computed. Results indicated that vibrational characteristics are strongly governed by grip force and to a lower extent by the racket properties. Grip force management drives the amount of energy, as well as its distribution, into the forearm. Furthermore, hand-grip can be assimilated to an adaptive filter which can significantly modify the spectral parameters propagating into the player's upper limb. A significant outcome is that these spectral characteristics are as much dependent on the player as on the racket. This contribution opens up new perspectives in equipment manufacture by underlining the need to account for player/racket interaction in the design process.

  5. 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

  6. Performance Outcomes After Metacarpal Fractures in National Basketball Association Players.

    PubMed

    Guss, Michael S; Begly, John P; Ramme, Austin J; Hinds, Richard M; Karia, Raj J; Capo, John T

    2016-12-01

    Background: The aim was to determine whether players in the National Basketball Association (NBA) who sustain metacarpal fractures demonstrate decreased performance upon return to competition when compared with their performance before injury and that of their control-matched peers. Methods: Data for 32 NBA players with metacarpal fractures incurred over 11 seasons (2002-2003 to 2012-2013) were obtained from injury reports, press releases, and player profiles (www.nba.com and www.basketballreference.com). Player age, body mass index (BMI), position, shooting hand, number of years in the league, and treatment (surgical vs nonsurgical) were recorded. Individual season statistics for the 2 seasons immediately prior to injury and the 2 seasons after injury, including player efficiency rating (PER), were obtained. Thirty-two controls matched by player position, age, and performance statistics were identified. A performance comparison of the cohorts was performed. Results: Mean age at the time of injury was 27 years with an average player BMI of 24. Players had a mean 5.6 seasons of NBA experience prior to injury. There was no significant change in PER when preinjury and postinjury performances were compared. Neither injury to their shooting hand nor operative management of the fracture led to a decrease in performance during the 2 seasons after injury. When compared with matched controls, no significant decline in performance in PER the first season and second season after injury was found. Conclusion: NBA players sustaining metacarpal fractures can reasonably expect to return to their preinjury performance levels following appropriate treatment.

  7. Shoulder 3D range of motion and humerus rotation in two volleyball spike techniques: injury prevention and performance.

    PubMed

    Seminati, Elena; Marzari, Alessandra; Vacondio, Oreste; Minetti, Alberto E

    2015-06-01

    Repetitive stresses and movements on the shoulder in the volleyball spike expose this joint to overuse injuries, bringing athletes to a career threatening injury. Assuming that specific spike techniques play an important role in injury risk, we compared the kinematic of the traditional (TT) and the alternative (AT) techniques in 21 elite athletes, evaluating their safety with respect to performance. Glenohumeral joint was set as the centre of an imaginary sphere, intersected by the distal end of the humerus at different angles. Shoulder range of motion and angular velocities were calculated and compared to the joint limits. Ball speed and jump height were also assessed. Results indicated the trajectory of the humerus to be different for the TT, with maximal flexion of the shoulder reduced by 10 degrees, and horizontal abduction 15 degrees higher. No difference was found for external rotation angles, while axial rotation velocities were significantly higher in AT, with a 5% higher ball speed. Results suggest AT as a potential preventive solution to shoulder chronic pathologies, reducing shoulder flexion during spiking. The proposed method allows visualisation of risks associated with different overhead manoeuvres, by depicting humerus angles and velocities with respect to joint limits in the same 3D space.

  8. Perceptual Training in Beach Volleyball Defence: Different Effects of Gaze-Path Cueing on Gaze and Decision-Making

    PubMed Central

    Klostermann, André; Vater, Christian; Kredel, Ralf; Hossner, Ernst-Joachim

    2015-01-01

    For perceptual-cognitive skill training, a variety of intervention methods has been proposed, including the so-called “color-cueing method” which aims on superior gaze-path learning by applying visual markers. However, recent findings challenge this method, especially, with regards to its actual effects on gaze behavior. Consequently, after a preparatory study on the identification of appropriate visual cues for life-size displays, a perceptual-training experiment on decision-making in beach volleyball was conducted, contrasting two cueing interventions (functional vs. dysfunctional gaze path) with a conservative control condition (anticipation-related instructions). Gaze analyses revealed learning effects for the dysfunctional group only. Regarding decision-making, all groups showed enhanced performance with largest improvements for the control group followed by the functional and the dysfunctional group. Hence, the results confirm cueing effects on gaze behavior, but they also question its benefit for enhancing decision-making. However, before completely denying the method’s value, optimisations should be checked regarding, for instance, cueing-pattern characteristics and gaze-related feedback. PMID:26648894

  9. Physical interpersonal relationships and social anxiety among online game players.

    PubMed

    Lo, Shao-Kang; Wang, Chih-Chien; Fang, Wenchang

    2005-02-01

    Many online game players spend inordinate amounts of time in their favorite virtual worlds. A large percentage of these players are teenagers who show behaviors normally associated with physical addiction. Parents, educators, and social scientists are therefore saying that online games are sources of social problems. The authors surveyed 174 Taiwanese college-age online players to collect data on the potential effects of online games on the quality of interpersonal relationships and levels of social anxiety. According to the results, the quality of interpersonal relationships decreased and the amount of social anxiety increased as the amount of time spent playing online games increased.

  10. Management of concussion in the professional football player.

    PubMed

    Pieroth, Elizabeth M; Hanks, Christopher

    2014-01-01

    There is no other sport that has come under greater scrutiny surrounding the incidence and treatment of concussion than football, and there is no other professional sports league that has experienced more intense focus of its handling of concussions than the National Football League (NFL). The NFL has received significant criticism of their management of concussion in players from both the popular press and the medical community. However, those working with active NFL players have changed their assessment and treatment of these injuries as the knowledge of concussions has evolved over time. We review the current approach to the management of concussions in the professional football player.

  11. Perceived hotness affects behavior of basketball players and coaches.

    PubMed

    Attali, Yigal

    2013-07-01

    Although "hot hands" in basketball are illusory, the belief in them is so robust that it not only has sparked many debates but may also affect the behavior of players and coaches. On the basis of an entire National Basketball Association season's worth of data, the research reported here shows that even a single successful shot suffices to increase a player's likelihood of taking the next team shot, increase the average distance from which this next shot is taken, decrease the probability that this next shot is successful, and decrease the probability that the coach will replace the player.

  12. Adductor Pollicis Longus Strain in a Professional Baseball Player

    PubMed Central

    Pinkowsky, Gregory J.; Roberts, John; Allred, Jeff; Pujalte, George G.; Gallo, Robert A.

    2013-01-01

    Thenar pain can represent a significant morbidity for a baseball player who relies on manual dexterity for gripping a bat and precise and accurate throws. While osseous, ligamentous, and neurovascular pathologies are commonly considered, musculotendinous injuries are often neglected in the differential diagnosis of thenar pain. We present a case of adductor pollicis longus strain as a cause of acute thenar pain in a baseball player. Adductor pollicis longus strains should be considered in any baseball player sustaining a hyperabduction force to the thumb. PMID:24459545

  13. Sport Nutrition Knowledge, Behaviors and Beliefs of High School Soccer Players.

    PubMed

    Manore, Melinda M; Patton-Lopez, Megan M; Meng, Yu; Wong, Siew Sun

    2017-04-01

    For adolescent athletes (14-18 years), data on sport nutrition knowledge, behaviors and beliefs are limited, especially based on sex, race/ethnicity and socioeconomic status. High school soccer players (n = 535; 55% female; 51% White, 41% Latino; 41% National School Lunch Program (NSLP) participants (80% Latino)) completed two questionnaires (demographic/health history and sport nutrition). The sport nutrition knowledge score was 45.6% with higher scores in NSLP-Whites vs. NSLP-Latinos (p < 0.01). Supplement knowledge differed by sex (16% lower in females; p = 0.047) and race/ethnicity (33% lower in Latinos; p < 0.001). Breakfast consumption was 57%; females ate breakfast less (50%) than males (60%; p < 0.001); NSLP-participants ate breakfast less (47%) than non-NSLP (62%; p < 0.001). Supplement use was 46%, with Latinos using more supplements than Whites do (p = 0.016). Overall, 30% used protein shakes, with females using less than males (p = 0.02), while use was twice as likely in Latino vs. White (p = 0.03). Overall, 45% reported their nutrient requirements were different from non-athlete peers. Latinos were less likely (p = 0.03) to report that their diet met nutritional requirements, but more than twice as likely to report that nutritional supplements were necessary for training (p < 0.001). Adolescent athletes, especially females and Latinos, would benefit from sport nutrition education that enhances food selection skills for health and sport performance.

  14. Number of Players and Relative Pitch Area per Player: Comparing Their Influence on Heart Rate and Physical Demands in Under-12 and Under-13 Football Players

    PubMed Central

    Castellano, Julen; Puente, Asier; Echeazarra, Ibon; Usabiaga, Oidui; Casamichana, David

    2016-01-01

    The aim of the present study is to analyse the influence of different large-sided games (LSGs) on the physical and physiological variables in under-12s (U12) and -13s (U13) soccer players. The effects of the combination of different number of players per team, 7, 9, and 11 (P7, P9, and P11, respectively) with three relative pitch areas, 100, 200, and 300 m2 (A100, A200, and A300, respectively), were analysed in this study. The variables analysed were: 1) global indicator such as total distance (TD); work:rest ratio (W:R); player-load (PL) and maximal speed (Vmax); 2) heart rate (HR) mean and time spent in different intensity zones of HR (<75%, 75–84%, 84–90% and >90%), and; 3) five absolute (<8, 8–13, 13–16 and >16 Km h-1) and three relative speed categories (<40%, 40–60% and >60% Vmax). The results support the theory that a change in format (player number and pitch dimensions) affects no similarly in the two players categories. Although it can seem that U13 players are more demanded in this kind of LSG, when the work load is assessed from a relative point of view, great pitch dimensions and/or high number of player per team are involved in the training task to the U12 players. The results of this study could alert to the coaches to avoid some types of LSGs for the U12 players such as: P11 played in A100, A200 or A300, P9 played in A200 or A300 and P7 played in A300 due to that U13>U12 in several physical and physiological variables (W:R, time spent in 84–90%HRmax, distance in 8–13 and 13–16 Km h-1 and time spent in 40–60%Vmax). These results may help youth soccer coaches to plan the progressive introduction of LSGs so that task demands are adapted to the physiological and physical development of participants. PMID:26752422

  15. Can programmed or self-selected physical activity affect physical fitness of adolescents?

    PubMed

    Neto, Cláudio F; Neto, Gabriel R; Araújo, Adenilson T; Sousa, Maria S C; Sousa, Juliana B C; Batista, Gilmário R; Reis, Victor M M R

    2014-09-29

    The aim of this study was to verify the effects of programmed and self-selected physical activities on the physical fitness of adolescents. High school adolescents, aged between 15 and 17 years, were divided into two experimental groups: a) a self-selected physical activity group (PAS) with 55 students (aged 15.7 ± 0.7 years), who performed physical activities with self-selected rhythm at the following sports: basketball, volleyball, handball, futsal and swimming; and b) a physical fitness training group (PFT) with 53 students (aged 16.0 ± 0.7 years), who performed programmed physical fitness exercises. Both types of activity were developed during 60 min classes. To assess physical fitness the PROESP-BR protocol was used. The statistical analysis was performed by repeated measures ANOVA. The measurements of pre and post-tests showed significantly different values after PFT in: 9 minute running test, medicine ball throw, horizontal jump, abdominal endurance, running speed and flexibility. After PAS differences were detected in abdominal endurance, agility, running speed and flexibility. The intervention with programmed physical activity promoted more changes in the physical abilities; however, in the self-selected program, agility was improved probably because of the practice of sports. Therefore, physical education teachers can use PFT to improve cardiorespiratory fitness and power of lower and upper limbs and PAS to improve agility of high school adolescents.

  16. Physical Fitness Qualities of Professional Rugby League Football Players: Determination of Positional Differences.

    ERIC Educational Resources Information Center

    Meir, Rudi; Newton, Robert; Curtis, Edgar; Fardell, Matthew; Butler, Benjamin

    2001-01-01

    Australian and English professional rugby players completed various physical fitness performance tests to determine differences when grouping players into three different rugby positional categories. Results found minimal differences in test scores on the basis of players' specific positions on a team, however, when players were grouped according…

  17. Developing Self-Efficacy within Role Players in Collegiate Athletics: A Mixed Methods Study

    ERIC Educational Resources Information Center

    Perchinsky, David A.

    2012-01-01

    The purpose of this study was to examine the differences in the level of self-efficacy between starting players and role players in a college Midwest Division III men's football team. The research questions were: 1) What differences in satisfaction levels, if any, can be found among starting players and role players with coach leadership, social…

  18. Control of striking velocity by table tennis players.

    PubMed

    Marinovic, Welber; Iizuka, Cristina Akiko; Freudenheim, Andrea Michele

    2004-12-01

    This study investigated how 7 skilled table tennis players controlled velocity of a forehand drive stroke when the ball's trajectory, velocity, and spin were modified. They hit a target in response to balls launched under four different conditions. The relative and absolute times used in the backswing phase showed no significant differences among conditions. When subjects hit fastballs, there was a significant change in the time required for them to reach the peak of velocity in the forward swing phase. In addition, players decreased the velocity of their strokes to hit fast-approaching balls. These results indicate that highly skilled table tennis players need to adjust the striking velocity and striking time (relative and absolute) required to reach the peak of velocity in the forward swing phase for these task modifications. Since they used slower movement velocities to hit faster-approaching balls, skilled table tennis players may override this speed-coupling process.

  19. Hypoconnectivity and hyperfrontality in retired American football players.

    PubMed

    Hampshire, Adam; MacDonald, Alex; Owen, Adrian M

    2013-10-17

    Recent research has raised concerns about the long-term neurological consequences of repetitive concussive and sub-concussive injuries in professional players of American Football. Despite this interest, the neural and psychological status of retired players remains unknown. Here, we evaluated the performances and brain activation patterns of retired National Football League players (NFL alumni) relative to controls using an fMRI-optimised neuropsychological test of executive function. Behaviourally, the NFL alumni showed only modest performance deficits on the executive task. By contrast, they showed pronounced hyperactivation and hypoconnectivity of the dorsolateral frontal and frontopolar cortices. Critically, abnormal frontal-lobe function was correlated with the number of times that NFL alumni reported having been removed from play after head injury and was evident in individual players. These results support the hypothesis that NFL alumni have a heightened probability of developing executive dysfunction and suggest that fMRI provides the most sensitive biomarker of the underlying neural abnormality.

  20. Violent Video Games May Not 'Desensitize' Players, Brain Scans Suggest

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_163987.html Violent Video Games May Not 'Desensitize' Players, Brain Scans ... 8, 2017 (HealthDay News) -- Young men who play violent video games the most -- at least two hours ...

  1. 'Pokemon Go' Players Add 2,000 Steps a Day

    MedlinePlus

    ... Pokemon Go' Players Add 2,000 Steps a Day Smartphone game benefits overweight, sedentary people most, researchers ... as likely to walk 10,000 steps a day than they were before taking up the game, ...

  2. Soccer players' fitting perception of different upper boot materials.

    PubMed

    Olaso Melis, J C; Priego Quesada, J I; Lucas-Cuevas, A G; González García, J C; Puigcerver Palau, S

    2016-07-01

    The present study assessed the influence of upper boot materials on fitting perception. Twenty players tested three soccer boots only differing in the upper boot material (natural calf leather, natural kangaroo leather and synthetic leather). Players reported fitting perception and preference on specific foot areas using a perceived fitting scale. Ratings were averaged for every foot area. Repeated measures ANOVA was used to analyze the differences between boots. The kangaroo leather boots were perceived tighter and closer to the preferred fitting in general fitting, metatarsals area and instep area. The synthetic leather boots were perceived as the loosest and as the most distant boot from the preferred fitting in medial front area and instep area. In conclusion, the type of upper boot material influences the fitting perception of soccer players. The kangaroo leather was the material whose fitting was perceived closest to the players fitting preference.

  3. Many College Football Players Lack Vitamin D: Study

    MedlinePlus

    ... fullstory_164139.html Many College Football Players Lack Vitamin D: Study Deficiency could put them at risk for muscle injuries ... vitamin D. Supplements are usually prescribed for a vitamin D deficiency, the researchers said. The study was to be ...

  4. Hypoconnectivity and Hyperfrontality in Retired American Football Players

    NASA Astrophysics Data System (ADS)

    Hampshire, Adam; MacDonald, Alex; Owen, Adrian M.

    2013-10-01

    Recent research has raised concerns about the long-term neurological consequences of repetitive concussive and sub-concussive injuries in professional players of American Football. Despite this interest, the neural and psychological status of retired players remains unknown. Here, we evaluated the performances and brain activation patterns of retired National Football League players (NFL alumni) relative to controls using an fMRI-optimised neuropsychological test of executive function. Behaviourally, the NFL alumni showed only modest performance deficits on the executive task. By contrast, they showed pronounced hyperactivation and hypoconnectivity of the dorsolateral frontal and frontopolar cortices. Critically, abnormal frontal-lobe function was correlated with the number of times that NFL alumni reported having been removed from play after head injury and was evident in individual players. These results support the hypothesis that NFL alumni have a heightened probability of developing executive dysfunction and suggest that fMRI provides the most sensitive biomarker of the underlying neural abnormality.

  5. Visual status of Nepalese national football and cricket players.

    PubMed

    Sapkota, Kishor; Koirala, Shashank; Shakya, Suraj; Chaudhary, Meenu; Paudel, Prakash

    2006-12-01

    This study was undertaken to assess the visual acuity, refractive status, stereopsis, colour vision and ocular morbidity of Nepalese national footballers and cricketers. Ninety-five national football and cricket players of different age group, who had at least played one international tournament representing Nepal, were included in the study. A thorough ocular examination of the players was done in the study period of six months, which revealed that higher-level professional players have significant visual problems. Among the players 70.0% had never had complete ocular examination, 8.0% were found with refractive error, 60.0% with stereo acuity equal or less than 40" of arc and 65.0% with ocular complaints.

  6. Ranking benchmarks of top 100 players in men's professional tennis.

    PubMed

    Reid, Machar; Morris, Craig

    2013-01-01

    In men's professional tennis, players aspire to hold the top ranking position. On the way to the top spot, reaching the top 100 can be seen as a significant career milestone. National Federations undertake extensive efforts to assist their players to reach the top 100. However, objective data considering reasonable ranking yardsticks for top 100 success in men's professional tennis are lacking. Therefore, it is difficult for National Federations and those involved in player development to give empirical programming advice to young players. By taking a closer look at the ranking history of professional male tennis players, this article tries to provide those involved in player development a more objective basis for decision-making. The 100 names, countries, birthdates and ranking histories of the top 100 players listed in the Association of Tennis Professionals (ATP) at 31 December 2009 were recorded from websites in the public domain. Descriptive statistics were reported for the ranking milestones of interest. Results confirmed the merits of the International Tennis Federation's junior tour with 91% of the top 100 professionals earning a junior ranking, the mean peak of which was 94.1, s=148.9. On average, top 100 professionals achieved their best junior rankings and earned their first ATP point at similar ages, suggesting that players compete on both the junior and professional tours during their transition. Once professionally ranked, players took an average 4.5, s=2.1 years to reach the ATP top 100 at the mean age of 21.5, s=2.6 years, which contrasts with the mean current age of the top 100 of 26.8, s=3.2. The best professional rankings of players born in 1982 or earlier were positively related to the ages at which players earned their first ATP point and then entered the top 100, suggesting that the ages associated with these ranking milestones may have some forecasting potential. Future work should focus on the change in top 100 demographics over time as well

  7. Unexpected cellular players in Rett syndrome pathology.

    PubMed

    Cronk, James C; Derecki, Noel C; Litvak, Vladimir; Kipnis, Jonathan

    2016-08-01

    Rett syndrome is a devastating neurodevelopmental disorder, primarily caused by mutations of methyl CpG-binding protein 2 (MeCP2). Although the genetic cause of disease was identified over a decade ago, a significant gap still remains in both our clinical and scientific understanding of its pathogenesis. Neurons are known to be primary players in pathology, with their dysfunction being the key in Rett syndrome. While studies in mice have demonstrated a clear causative - and potential therapeutic - role for neurons in Rett syndrome, recent work has suggested that other tissues also contribute significantly to progression of the disease. Indeed, Rett syndrome is known to present with several common peripheral pathologies, such as osteopenia, scoliosis, gastrointestinal problems including nutritional defects, and general growth deficit. Mouse models assessing the potential role of non-neuronal cell types have confirmed both roles in disease and potential therapeutic targets. A new picture is emerging in which neurons both initiate and drive pathology, while dysfunction of other cell types and peripheral tissues exacerbate disease, possibly amplifying further neurologic problems, and ultimately result in a positive feedback loop of progressively worsening symptoms. Here, we review what is known about neuronal and non-neuronal cell types, and discuss how this new, integrative understanding of the disease may allow for additional clinical and scientific pathways for treating and understanding Rett syndrome.

  8. Physiological profile of women's Lacrosse players.

    PubMed

    Enemark-Miller, Emily A; Seegmiller, Jeff G; Rana, Sharon R

    2009-01-01

    Increasing participation rates for women's lacrosse necessitate a clear understanding of fitness parameters for this athlete group. However, limited sport-specific information is available. We described the physiological profile of an NCAA Division I women's lacrosse team to provide current data for this specific athlete group. A descriptive analysis was used to assess physiologic variables. Twenty-four members (age 20.0 +/- 1.4 years, mass 64.7 +/- 9.6 kg, height 163.2 +/- 25.6 cm) of an NCAA Division I women's lacrosse team volunteered and provided consent. Fitness tests were conducted by the same researcher and were selected from standard physical fitness assessments. Tests included cardiovascular endurance (Bruce Protocol VO2max test and 1-mile run), flexibility (sit-and-reach test), muscular endurance (push-ups, sit-ups, and 60% of 1RM back squat), muscular strength (one-repetition maximum [1RM] back squat and 1RM bench press), body composition (BOD POD), muscle torque (quadriceps maximal voluntary isometric contraction), grip strength (hand dynamometer), vertical jump (Vertec vertical column), endurance strength (100- and 200-yard sprints), and Q-angle. Our results indicate that our sample of lacrosse players exhibited similar fitness characteristics to basketball, soccer, and track athletes. However, we found only average flexibility and a higher percentage of body fat, indicating possible areas for improvement in lacrosse training programs.

  9. Analyzing online game players: from materialism and motivation to attitude.

    PubMed

    Chang, Ju-Hui; Zhang, Hongxia

    2008-12-01

    The online game market has been growing rapidly and has received an increasing amount of attention in recent years. The results of a survey conducted in China to explore online game players' attitude formation reveal that (a) the online game player's level of materialism positively influences the motivation for playing, (b) motivation positively influences attitude toward online games, and (c) motivation fully mediates the effects of materialism on attitude.

  10. Upper extremity sensorimotor control among collegiate football players.

    PubMed

    Laudner, Kevin G

    2012-03-01

    Injuries stemming from shoulder instability are very common among athletes participating in contact sports, such as football. Previous research has shown that increased laxity negatively affects the function of the sensorimotor system potentially leading to a pathological cycle of shoulder dysfunction. Currently, there are no data detailing such effects among football players. Therefore, the purpose of this study was to examine the differences in upper extremity sensorimotor control among football players compared with that of a control group. Forty-five collegiate football players and 70 male control subjects with no previous experience in contact sports participated. All the subjects had no recent history of upper extremity injury. Each subject performed three 30-second upper extremity balance trials on each arm. The balance trials were conducted in a single-arm push-up position with the test arm in the center of a force platform and the subjects' feet on a labile device. The trials were averaged, and the differences in radial area deviation between groups were analyzed using separate 1-way analyses of variance (p < 0.05). The football players showed significantly more radial area deviation of the dominant (0.41 ± 1.23 cm2, p = 0.02) and nondominant arms (0.47 ± 1.63 cm2, p = 0.03) when compared with the control group. These results suggest that football players may have decreased sensorimotor control of the upper extremity compared with individuals with no contact sport experience. The decreased upper extremity sensorimotor control among the football players may be because of the frequent impacts accumulated during football participation. Football players may benefit from exercises that target the sensorimotor system. These findings may also be beneficial in the evaluation and treatment of various upper extremity injuries among football players.

  11. Biomechanics of heading a soccer ball: implications for player safety.

    PubMed

    Babbs, C F

    2001-08-08

    To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton's second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player"s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater "touch" and "playability", measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  12. Differences in energy capacities between tennis players and runners.

    PubMed

    Novak, Dario; Vucetić, Vlatko; Zugaj, Sanja

    2013-05-01

    The primary purpose of this study was to determine differences between elite athletes and tennis players in order to provide a clearer picture regarding the energy demands in modern tennis. Forty-eight (48) athletes and 24 tennis players from Croatian national leagues were compared in morphological and physiological parameters of an all-out incremental treadmill test with gas exchange measurements. Tennis players' HRmax (192.96+/-7.75 bpm) shows values that are most different to 400-meters sprinters (200.13+/-6.95 bpm). Maximum running speed of tennis players on the treadmill (vmax) is no different with the speed achieved by sprinters, while there are significant differences among other athletes. Values in running speed at anaerobic threshold (vAnT) show no statistically significant difference with the values for athlete sprinters and 400-m sprinters. Values of RvO2max for tennis players indicate significant similarities with athlete sprinters and 400-m sprinters while the values of RvO2AnT are nearly identical with the values for sprinters and show no statistically significant differences (p<0.05). The results indicate that values achieved by tennis players approximate most different those of the middle and long distance runners. This singles out the possible importance of the anaerobic capacity and the high level of sprint endurance in tennis players. Knowing these characteristics is the basis for planning and implementing training systems that will enable the increase and optimal usage of energy capacities of tennis players in possibly improving sports results.

  13. An Analysis of Futsal Players' Self-Esteem Levels

    ERIC Educational Resources Information Center

    Kocak, Mehmet

    2015-01-01

    The purpose of this study is to investigate the self-esteem levels of futsal players according to certain variables. The samples of the study constituted 119 females and 96 males; a total of 215 players with an average age of 21.57 ± 2.20 years. The research was carried out with the end of "Rosenberg self-esteem Scale" developed by…

  14. Hardiness and situation efficacy at elite basketball players.

    PubMed

    Sindik, Josko; Adzija, Maja

    2013-03-01

    The main aims of the study were: to explore the latent structure of the construct of hardiness at Croatian top basketball players and to gain an understanding of the relationship between obtained hardiness dimensions and situation-related efficacy in basketball. Situation efficacy of individual basketball players in top teams is linked to the constellation of a number of relevant anthropological and specific psychological features that influence the behavior of basketball players in stressful situations during training, and especially during basketball games. One of the most important psychological characteristics for the resistance of an individual to these kinds of stress is hardiness. In the research is used a Short Hardiness Scale (SHS), which is metrically adapted to the sample of Croatian top basketball players. The questionnaire was applied to a group of 107 top basketball players, independently in all nine A-1 Croatian basketball league teams. The correlations of the hardiness dimensions with the standard and derived parameters of basketball players' situation efficacy are established, as well as with log variables. The analysis of instrument latent structure for hardiness measurement indicates the existence of two dimensions characteristic for the Croatian sample of top basketball players, which could be interpreted as a challenge and a control - commitment. A relatively small percentage of the explained variance (about 40%) suggests the possibility of defining the concept of hardiness specific for basketball situations. Low but statistically significant positive correlations were found between the dimension of control - commitment and a larger number of standard and derived parameters of situation efficacy. Statistically significant correlations between the dimension of challenge and the situation efficacy parameters or log variables are not found. This study has the main importance in cultural adjustment of hardiness to Croatian top basketball players

  15. Physiological profiles of Hong Kong élite soccer players.

    PubMed Central

    Chin, M K; Lo, Y S; Li, C T; So, C H

    1992-01-01

    Most physiological profiles of élite soccer players originate from Western Europe and North America. Unfortunately, there is a scarcity of descriptive data on the physical characteristics of Asian soccer players. Therefore, the purpose of this study was to evaluate the physiological profiles of élite soccer players in Hong Kong. It was conducted in conjunction with the selection of the Hong Kong team before the 1990 Beijing Asian Games. In all, 24 professional soccer players were selected from a pool of 180 players as subjects for the study. The following means(s.d.) were observed: height 173.4(4.6) cm; weight 67.7(5.0) kg; body fat 7.3(3.0)%; forced vital capacity (FVC) 5.1(0.6) l; maximum oxygen uptake (VO2max) 59.1(4.9) ml kg-1 min-1; anaerobic threshold (AT 80.0(7.2)% of VO2max; alactic power index 13.5(2.4) W kg-1; lactic work index 298(27) J kg-1; peak isokinetic dominant knee extensor and flexor strengths 2.72(0.36) Nm kg-1 and 1.65(0.20) Nm kg-1. On average the physique of Hong Kong soccer players appeared to be smaller and lighter than those found in Europe, which may be one of the key factors that contribute to the lack of success of Hong Kong soccer teams in international competition. PMID:1490221

  16. Caffeine supplementation and reactive agility in elite youth soccer players.

    PubMed

    Jordan, J Bradley; Korgaokar, Ajit; Farley, Richard S; Coons, John M; Caputo, Jennifer L

    2014-05-01

    This study examined the effects of caffeine supplementation (6 mg·kg-1) on performance of a reactive agility test (RAT) in 17 elite, male, youth (M = 14 y) soccer players. Using a double-blind, repeated-measures design, players completed 4 days of testing on the RAT after a standardized warm-up. On day 1, anthropometric measurements were taken and players were accommodated to the RAT. On day 2, baseline performance was established. Caffeine or placebo conditions were randomly assigned on day 3 and the condition was reversed on day 4. Players completed 3 randomized trials of the RAT on days 2, 3, and 4 with at least 1 trial to the players' dominant and nondominant sides. There were no significant differences among conditions in reaction time (RT) to the dominant side, heart rates at any point of measurement, or ratings of perceived exertion (RPE) after completion of the warm-up. Caffeine produced faster RT to the nondominant side (P = .041) and higher RPE at the conclusion of the RAT (P = .013). The effect on the total time (TT) to complete the agility test to the nondominant side approached significance (P = .051). Sprint time and TT to either side did not differ. Caffeine supplementation may provide ergogenic benefit to elite, male, youth soccer players.

  17. Injuries of veteran football (soccer) players in Germany.

    PubMed

    Hammes, Daniel; Aus Der Fünten, Karen; Kaiser, Stephanie; Frisen, Eugen; Dvorák, Jirí; Meyer, Tim

    2015-01-01

    There is a lack of injury data for the population of veteran football players. Therefore, a prospective study was conducted to investigate injury incidences and characteristics. Over one season, injuries and exposure of 18 teams (n = 265 players, age: 44.2±7.3 years, BMI: 26.6±3.2 kg/m(2)) were documented. Sixty-three players sustained a total of 88 injuries during the season. The incidence of training injuries (4.5 per 1000 hours) was significantly lower than of match injuries (24.7 per 1000 hours). The majority of injuries (n = 73; 83%) were located at the lower extremities, 52 (47%) were muscle injuries. The injury incidence of veteran football players is similar to other male football players of different skill levels and age groups, indicating a need for the implementation of preventive measures. Prevention programmes should consider the specific injury characteristics, with more muscle injuries in this population compared with younger football players.

  18. Player acceleration and deceleration profiles in professional Australian football.

    PubMed

    Johnston, R J; Watsford, M L; Austin, D; Pine, M J; Spurrs, R W

    2015-09-01

    This study aimed to determine the validity and reliability of global positioning system (GPS) units for measuring a standardized set of acceleration and deceleration zones and whether these standardized zones were capable of identifying differences between playing positions in professional Australian football. Eight well trained male participants were recruited to wear two 5 Hz or 10 Hz GPS units whilst completing a team sport simulation circuit to measure acceleration and deceleration movements. For the second part of this article 30 professional players were monitored between 1-29 times using 5 Hz and 10 Hz GPS units for the collection of acceleration and deceleration movements during the 2011 and 2012 Australian Football League seasons. Players were separated into four distinct positional groups - nomadic players, fixed defenders, fixed forwards and ruckman. The GPS units analysed had good to poor levels of error for measuring the distance covered (<19.7%), time spent (<17.2%) and number of efforts performed (<48.0%) at low, moderate and high acceleration and deceleration zones. The results demonstrated that nomadic players and fixed defenders perform more acceleration and deceleration efforts during a match than fixed forwards and ruckman. These studies established that these GPS units can be used for analysing the distance covered and time spent at the acceleration and deceleration zones used. Further, these standardized zones were proven to be capable of distinguishing between player positions, with nomadic players and fixed defenders required to complete more high acceleration and deceleration efforts during a match.

  19. Temperamental Predictive Factors for Success in Korean Professional Baseball Players

    PubMed Central

    Kang, Kyoung Doo; Hannon, James C.; Hall, Morgan S.; Choi, Jae Won

    2015-01-01

    Objective In this five-year cohort study, we hypothesize that factors of temperament and character in professional baseball players predict the speed of obtaining success and the quality of success as well as anxiety control. Methods Participants included 120 male rookie players from the Korea Baseball Organization (KBO) and 107 male non-players with no history of playing baseball. The personality/characters and state/trait anxieties of participants were assessed with the Temperament and Character Inventory (TCI) and Spielberg's State-Trait Anxiety Inventory-Y (STAI-Y). Over the duration of five years, all the players were subsequently classified into either a success group (major leaguers) or a non-success group (non-major leaguers), depending on their status in the professional baseball league in Korea. Results The players in the group of starters had higher novelty seeking (NS) scores than those of non-starters. The reward dependence (RD) scores of the success group were higher than those of the non-success group. The state anxiety scores in the starter group were negatively correlated with NS scores. The state and trait anxieties in the non-success group were positively correlated with RD scores. Conclusion The results of this study suggest that predictive temperamental factors for success in baseball players include traits of novelty seeking and reward dependence. PMID:26508956

  20. Do Stereotypic Images in Video Games Affect Attitudes and Behavior? Adolescents' Perspectives.

    PubMed

    Henning, Alexandra; Brenick, Alaina; Killen, Melanie; O'Connor, Alexander; Collins, Michael J

    This study examined adolescents' attitudes about video games along with their self-reported play frequency. Ninth and eleventh grade students (N = 361), approximately evenly divided by grade and gender, were surveyed about whether video games have stereotypic images, involve harmful consequences or affect one's attitudes, whether game playing should be regulated by parents or the government, and whether game playing is a personal choice. Adolescents who played video games frequently showed decreased concern about the effects that games with negatively stereotyped images may have on the players' attitudes compared to adolescents who played games infrequently or not at all. With age, adolescents were more likely to view images as negative, but were also less likely to recognize stereotypic images of females as harmful and more likely to judge video-game playing as a personal choice. The paper discusses other findings in relation to research on adolescents' social cognitive judgments.

  1. Violent video game players and non-players differ on facial emotion recognition.

    PubMed

    Diaz, Ruth L; Wong, Ulric; Hodgins, David C; Chiu, Carina G; Goghari, Vina M

    2016-01-01

    Violent video game playing has been associated with both positive and negative effects on cognition. We examined whether playing two or more hours of violent video games a day, compared to not playing video games, was associated with a different pattern of recognition of five facial emotions, while controlling for general perceptual and cognitive differences that might also occur. Undergraduate students were categorized as violent video game players (n = 83) or non-gamers (n = 69) and completed a facial recognition task, consisting of an emotion recognition condition and a control condition of gender recognition. Additionally, participants completed questionnaires assessing their video game and media consumption, aggression, and mood. Violent video game players recognized fearful faces both more accurately and quickly and disgusted faces less accurately than non-gamers. Desensitization to violence, constant exposure to fear and anxiety during game playing, and the habituation to unpleasant stimuli, are possible mechanisms that could explain these results. Future research should evaluate the effects of violent video game playing on emotion processing and social cognition more broadly.

  2. Monitoring for overreaching in rugby league players.

    PubMed

    Coutts, Aaron J; Reaburn, Peter; Piva, Terrence J; Rowsell, Greg J

    2007-02-01

    The aim of this study was to identify indicators of non-functional overreaching (NFOR) in team sport athletes undertaking intensive training loads. Eighteen semi-professional rugby league players were randomly assigned into two pair matched groups. One group completed 6 weeks of normal training (NT) whilst the other group was deliberately overreached through intensified training (IT). Both groups then completed the same 7-day stepwise training load reduction taper. Multistage fitness test (MSFT) performance, VO2 (max), peak aerobic running velocity (V (max)), maximal heart rate, vertical jump, 10-s cycle sprint performance and body mass were measured pre- and post-training period and following the taper. Hormonal, haematological and immunological parameters were also measured pre-training and following weeks 2, 4 and 6 of training and post-taper. MANOVA for repeated measures with contrast analysis indicated that MSFT performance and VO2 (max) were significantly reduced in the IT group over time and condition, indicating that a state of overreaching was attained. However, the only biochemical measure that was significantly different between the IT and NT group was the glutamine to glutamate (Gln/Glu) ratio even though testosterone, testosterone to cortisol (T/C) ratio, plasma glutamate, and CK activity were significantly changed after training in both groups. Positive endurance and power performance changes were observed post-taper in the IT group confirming NFOR. These changes were associated with increases in the T/C ratio and the Gln/Glu ratio and decreases in plasma glutamate and CK activity. These results indicate that although there was no single reliable biochemical marker of NFOR in these athletes, the Gln/Glu ratio and MSFT test may be useful measures for monitoring responses to IT in team sport athletes.

  3. Metabolic Demands of Match Performance in Young Soccer Players

    PubMed Central

    Aslan, Alper; Acikada, Caner; Güvenç, Alpay; Gören, Hasan; Hazir, Tahir; Özkara, Asaf

    2012-01-01

    The aim of the present study was to determine metabolic responses, movement patterns and distance covered at running speeds corresponding to fixed blood lactate concentrations (FBLs) in young soccer players during a match play. A further aim of the study was to evaluate the relationships between FBLs, maximal oxygen consumption (VO2max) and distance covered during a game. A multistage field test was administered to 32 players to determine FBLs and VO2max. Blood lactate (LA), heart rate (HR) and rate of perceived exertion (RPE) responses were obtained from 36 players during tournament matches filmed using six fixed cameras. Images were transferred to a computer, for calibration and synchronization. In all players, values for LA and HR were higher and RPE lower during the 1st half compared to the 2nd half of the matches (p < 0.01). Players in forward positions had higher LA levels than defenders, but HR and RPE values were similar between playing positions. Total distance and distance covered in jogging, low-moderate-high intensity running and low intensity sprint were higher during the 1st half (p < 0.01). In the 1st half, players also ran longer distances at FBLs [p<0.01; average running speed at 2mmol·L-1 (FBL2): 3.32 ± 0.31m·s-1 and average running speed at 4mmol·L-1 (FBL4): 3.91 ± 0.25m·s-1]. There was a significant difference between playing positions in distance covered at different running speeds (p < 0.05). However, when distance covered was expressed as FBLs, the players ran similar distances. In addition, relationships between FBLs and total distance covered were significant (r = 0.482 to 0.570; p < 0.01). In conclusion, these findings demonstrated that young soccer players experienced higher internal load during the 1st half of a game compared to the 2nd half. Furthermore, although movement patterns of players differed between playing positions, all players experienced a similar physiological stress throughout the game. Finally, total distance

  4. Treating Children and Adolescents

    MedlinePlus

    ... Children and Adolescents Go Back Treating Children and Adolescents Email Print + Share For the most part, the ... tailored, based upon the child's weight. Children and adolescents are moving through a period of physical and ...

  5. Adolescent violence.

    PubMed

    Williams-Evans, Shiphrah A; Myers, Joy Sher'ron

    2004-01-01

    The purpose of this document is to provide an overview of the rising occurrences of adolescent violence in the American school systems and how various theories can be used to assist in understanding this phenomenon. The authors have become increasingly interested in this topic, after direct involvement in the summer of 2001. There were a number of students who were attending summer school as a result of consistent out-of-school suspensions for violent acts. The procedure to process through the system with these students was to suspend them, resulting in the student subsequently failing their present grade. The school was located in a community known for its high rate of violence and criminal activity. Various types of adolescent violence exist in our schools. Studies have reported that violent adolescents may come from familial environments that are full of social and interpersonal conflicts (Gray & Foshee, 1999). This paper discusses the development of a research plan to investigate the number and type of adolescent violent occurrences in a southern middle school setting.

  6. Adolescent homosexuality.

    PubMed

    Stronski Huwiler, S M; Remafedi, G

    1998-01-01

    Homosexuality has existed in all civilizations, but societal disapproval and cultural taboos have negatively influenced its recognition. A significant percentage of youths identify themselves as homosexual, and even more experience sex with the same sex or are confused about sexual feelings. A unifying etiological theory attributes the expression of sexual orientation to genes that shape the central nervous system's development, organization, and structure via prenatal sex steroids. Environmental factors may influence the expression of genetic potential. Several models of psychosocial development describe initial stages of awareness and confusion about same-sex attractions, followed by acknowledgement of homosexuality, disclosure to others, and eventual integration of sexual identity into a comprehensive sense of self. Stressors related to isolation, stigma, and violence may predispose homosexual adolescents to impaired social, emotional, and physical health, resulting in depression and suicide, school problems, substance abuse, running away eating disorders, risky sexual behavior, and illegal conduct. As with all adolescents, the overall goals in the care of homosexual youth are to promote normal adolescent development, social and emotional well-being, and physical health. A comprehensive, multidisciplinary approach is required to address medical, mental health, and psychosocial issues within the context of the adolescents' community and culture.

  7. Cavum Septum Pellucidum in Retired American Pro-Football Players

    PubMed Central

    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

    Abstract 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. PMID:25970145

  8. Prevalent Morphometric Vertebral Fractures in Professional Male Rugby Players

    PubMed Central

    Hind, Karen; Birrell, Fraser; Beck, Belinda

    2014-01-01

    There is an ongoing concern about the risk of injury to the spine in professional rugby players. The objective of this study was to investigate the prevalence of vertebral fracture using vertebral fracture assessment (VFA) dual energy X-ray absorptiometry (DXA) imaging in professional male rugby players. Ninety five professional rugby league (n = 52) and union (n = 43) players (n = 95; age 25.9 (SD 4.3) years; BMI: 29.5 (SD 2.9) kg.m2) participated in the research. Each participant received one VFA, and one total body and lumbar spine DXA scan (GE Lunar iDXA). One hundred and twenty vertebral fractures were identified in over half of the sample by VFA. Seventy four were graded mild (grade 1), 40 moderate (grade 2) and 6 severe (grade 3). Multiple vertebral fractures (≥2) were found in 37 players (39%). There were no differences in prevalence between codes, or between forwards and backs (both 1.2 v 1.4; p>0.05). The most common sites of fracture were T8 (n = 23), T9 (n = 18) and T10 (n = 21). The mean (SD) lumbar spine bone mineral density Z-score was 2.7 (1.3) indicating high player bone mass in comparison with age- and sex-matched norms. We observed a high number of vertebral fractures using DXA VFA in professional rugby players of both codes. The incidence, aetiology and consequences of vertebral fractures in professional rugby players are unclear, and warrant timely, prospective investigation. PMID:24846310

  9. 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

  10. Automatic acquisition of motion trajectories: tracking hockey players

    NASA Astrophysics Data System (ADS)

    Okuma, Kenji; Little, James J.; Lowe, David

    2003-12-01

    Computer systems that have the capability of analyzing complex and dynamic scenes play an essential role in video annotation. Scenes can be complex in such a way that there are many cluttered objects with different colors, shapes and sizes, and can be dynamic with multiple interacting moving objects and a constantly changing background. In reality, there are many scenes that are complex, dynamic, and challenging enough for computers to describe. These scenes include games of sports, air traffic, car traffic, street intersections, and cloud transformations. Our research is about the challenge of inventing a descriptive computer system that analyzes scenes of hockey games wher