Science.gov

Sample records for adolescent sprint athletes

  1. Dietary Acid-Base Balance in Adolescent Sprint Athletes: A Follow-up Study

    PubMed Central

    Aerenhouts, Dirk; Deriemaeker, Peter; Hebbelinck, Marcel; Clarys, Peter

    2011-01-01

    Sprinters are advised to include additional protein sources in their diet. Basal metabolism and vigorous physical activities generate hydrogen ions that need to be buffered. The present follow-up study estimates the dietary potential renal acid load (PRAL) and net endogenous acid production (NEAP) in adolescent sprint athletes. Seven-day food diaries and anthropometrics of 60 adolescent sprint athletes (mean age at start 14.7 ± 1.9 years) were collected every six months over a three year period. Comparisons were made between athletes with a negative (PRAL(−)) versus positive PRAL (PRAL(+)). For the entire sample, mean PRAL values of up to 6 mEq/day were slightly positive despite a relatively high protein intake of around 1.5 g/kg. The NEAP ranging between 42 and 46 mEq/day remained stable during the study period. Athletes with a PRAL(−) (−8 to −10 mEq/day) consumed significantly more fruit and fruit juice than athletes with a PRAL(+) (+9 to 14 mEq/day). Athletes with a PRAL(+) did not consume more meat, fish and poultry than athletes with a PRAL(−). Grains and dairy products were only discriminative between the two groups on one measurement occasion. Lowering the PRAL can be obtained by increasing the consumption of potatoes, fruits, vegetables and vegetable soup. PMID:22254092

  2. Influence of growth rate on nitrogen balance in adolescent sprint athletes.

    PubMed

    Aerenhouts, Dirk; Van Cauwenberg, Jelle; Poortmans, Jacques Remi; Hauspie, Ronald; Clarys, Peter

    2013-08-01

    This study aimed to estimate nitrogen balance and protein requirements in adolescent sprint athletes as a function of growth rate and physical development. Sixty adolescent sprint athletes were followed up biannually over a 2-yr period. Individual growth curves and age at peak height velocity were determined. Skeletal muscle mass (SMM) was estimated based on anthropometric measurements and fat mass was estimated by underwater densitometry. Seven-day diet and physical activity diaries were completed to estimate energy balance and protein intake. Nitrogen analysis of 24-hr urine samples collected on 1 weekday and 1 weekend day allowed calculation of nitrogen balance. Body height, weight, and SMM increased throughout the study period in both genders. Mean protein intakes were between 1.4 and 1.6 g kg-1 day-1 in both genders. A protein intake of 1.46 g kg-1 day-1 in girls and 1.35 g kg-1 day-1 in boys was needed to yield a positive nitrogen balance. This did not differ between participants during and after their growth spurt. None of the growth parameters was significantly related to nitrogen balance. It can be concluded that a mean protein intake around 1.5 g kg-1 day-1 was sufficient to stay in a positive nitrogen balance, even during periods of peak growth. Therefore, protein intake should not be enhanced in peak periods of linear or muscular growth.

  3. Energy and macronutrient intake in adolescent sprint athletes: a follow-up study.

    PubMed

    Aerenhouts, Dirk; Deriemaeker, Peter; Hebbelinck, Marcel; Clarys, Peter

    2011-01-01

    Macronutrient intake, height, weight, and body composition of 60 adolescent sprint athletes were estimated every 6 months over 3 years. Seven-day food records were analysed based on the Belgian and Dutch food databanks. The age of participants at the start of the 3-year study was 14.8 ± 1.6 years for female athletes and 14.7 ± 1.9 years for male athletes. Girls and boys gained height (3.4 ± 4.6 cm and 5.9 ± 6.6 cm respectively) and weight (5.6 ± 3.5 kg and 8.7 ± 5.5 kg respectively), whereas percent body fat remained unchanged in both girls and boys (around 17.0% and 8.5% respectively). Mean protein intake of around 1.5 g · kg⁻¹ body weight was within recommendations on each occasion for both sexes. Carbohydrate intakes between 5 and 7 g · kg⁻¹ body weight support a training programme of moderate intensity. Total and saturated fat intakes were high at the start of the study (girls: 31.8 ± 3.5% and 12.2 ± 2.0% of energy intake; boys: 30.3 ± 4.6% and 12.0 ± 1.9% of energy intake) and it appeared to be difficult to achieve and maintain lower intakes. Consistent low fluid intakes around 40 ml · kg⁻¹ body weight were observed. General non-stringent advice for improvement of the diet resulted in significant favourable changes only for the consumption of wholegrain bread, vegetables, and soft drinks. Dietary habits of adolescent sprint athletes are not always according to guidelines and are relatively stable but repeated advice can induce moderate improvements. PMID:21086211

  4. Estimating Body Composition in Adolescent Sprint Athletes: Comparison of Different Methods in a 3 Years Longitudinal Design

    PubMed Central

    Aerenhouts, Dirk

    2015-01-01

    A recommended field method to assess body composition in adolescent sprint athletes is currently lacking. Existing methods developed for non-athletic adolescents were not longitudinally validated and do not take maturation status into account. This longitudinal study compared two field methods, i.e., a Bio Impedance Analysis (BIA) and a skinfold based equation, with underwater densitometry to track body fat percentage relative to years from age at peak height velocity in adolescent sprint athletes. In this study, adolescent sprint athletes (34 girls, 35 boys) were measured every 6 months during 3 years (age at start = 14.8 ± 1.5yrs in girls and 14.7 ± 1.9yrs in boys). Body fat percentage was estimated in 3 different ways: 1) using BIA with the TANITA TBF 410; 2) using a skinfold based equation; 3) using underwater densitometry which was considered as the reference method. Height for age since birth was used to estimate age at peak height velocity. Cross-sectional analyses were performed using repeated measures ANOVA and Pearson correlations between measurement methods at each occasion. Data were analyzed longitudinally using a multilevel cross-classified model with the PROC Mixed procedure. In boys, compared to underwater densitometry, the skinfold based formula revealed comparable values for body fatness during the study period whereas BIA showed a different pattern leading to an overestimation of body fatness starting from 4 years after age at peak height velocity. In girls, both the skinfold based formula and BIA overestimated body fatness across the whole range of years from peak height velocity. The skinfold based method appears to give an acceptable estimation of body composition during growth as compared to underwater densitometry in male adolescent sprinters. In girls, caution is warranted when interpreting estimations of body fatness by both BIA and a skinfold based formula since both methods tend to give an overestimation. PMID:26317426

  5. Lower extremity kinematics of athletics curve sprinting.

    PubMed

    Alt, Tobias; Heinrich, Kai; Funken, Johannes; Potthast, Wolfgang

    2015-01-01

    Curve running requires the generation of centripetal force altering the movement pattern in comparison to the straight path run. The question arises which kinematic modulations emerge while bend sprinting at high velocities. It has been suggested that during curve sprints the legs fulfil different functions. A three-dimensional motion analysis (16 high-speed cameras) was conducted to compare the segmental kinematics of the lower extremity during the stance phases of linear and curve sprints (radius: 36.5 m) of six sprinters of national competitive level. Peak joint angles substantially differed in the frontal and transversal plane whereas sagittal plane kinematics remained unchanged. During the prolonged left stance phase (left: 107.5 ms, right: 95.7 ms, straight: 104.4 ms) the maximum values of ankle eversion (left: 12.7°, right: 2.6°, straight: 6.6°), hip adduction (left: 13.8°, right: 5.5°, straight: 8.8°) and hip external rotation (left: 21.6°, right: 12.9°, straight: 16.7°) were significantly higher. The inside leg seemed to stabilise the movement in the frontal plane (eversion-adduction strategy) whereas the outside leg provided and controlled the motion in the horizontal plane (rotation strategy). These results extend the principal understanding of the effects of curve sprinting on lower extremity kinematics. This helps to increase the understanding of nonlinear human bipedal locomotion, which in turn might lead to improvements in athletic performance and injury prevention. PMID:25495196

  6. ADHD and Adolescent Athletes

    PubMed Central

    Nazeer, Ahsan; Mansour, Miriam; Gross, Kathleen A.

    2014-01-01

    Attention-deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that affects the child and adolescent population. It is characterized by impairment in attention/concentration, hyperactivity, and impulsivity, all of which can impact performance of athletes. ADHD treatment within the athletic population is a unique challenge. The research in this field has been relatively limited. The National Collegiate Athletic Association and International Olympic Committee both regulate the use of psychostimulants for treatment of ADHD due to their performance-enhancing effects. In this article, authors have discussed the screening methods, pharmacological treatment, side effects, and behavioral approaches for the treatment of ADHD in adolescent athletes. PMID:24987666

  7. Acute Responses to 10×15 m Repeated Sprint Ability Exercise in Adolescent Athletes: the Role of Change of Direction and Sport Specialization

    PubMed Central

    Nikolaidis, Pantelis Theodoros; Meletakos, Panagiotis; Tasiopoulos, Ioannis; Kostoulas, Ioannis; Ganavias, Panagiotis

    2016-01-01

    Background The repeated sprint ability (RSA) has been studied with protocols using distances longer than 20 m per sprint, whereas basketball players cover on average less than 20-meter distance per sprint during match. Objectives The aim of the present study was to examine the physiological impact of 10 × 15 m RSA test in straight-line (RSASL) or with change of direction (RSACOD), i.e. 10 × (7.5 + 7.5 m)) in young national level basketball players. Patients and Methods Young basketball players (n = 11, age 17.1 (1.0) years, body mass 76 (6) kg, height 184 (4) cm, body mass index 22.6 (1.8) kgm-2, sport experience 6.9 (2.7) years, mean (standard deviation)) and a control group consisting of high-school athletes (n = 7, 16.1 (0.7) years, 67 (6) kg, 177 (6) cm, 21.5 (1.0) kgm-2, 7.7 (1.6) years, respectively) performed RSASL and RSACOD on a counter-balanced order. Sprints started every 30 seconds (active recovery) and there was 30 minutes break between RSA protocols; time variables were total time (TT), best time (BT) and fatigue index (FI). Countermovement jump (CMJ) was tested before and after each RSA protocol. Heart rate (HR) was continuously monitored during testing procedures. Results Compared with RSASL, TT and BT were worst in RSACOD (38.13 vs. 27.52 s and 3.67 vs. 2.66 s, P < 0.001, respectively), whereas FI did not differ (3.8 vs. 3.5%, P = 0.388). A 2 × 2 repeated measures ANOVA showed main effect of RSA on CMJ (pre-test vs. post-test, increase + 1.8 cm, P = 0.020, η2 = 0.28); there was neither main effect of RSA protocols (RSASL vs. RSACOD +0.7 cm, P = 0.251, η2 = 0.08) nor an interaction between pre-post measurements and RSA protocols (P = 0.578, η2 = 0.02). Compared with RSASL, RSACOD induced higher mean and peak HR responses (175 vs 172 bpm, P < 0.001, and 185 vs 182 bpm, P = 0.002, respectively). No statistical difference was observed between basketball players and control group neither for TT (27.98 vs. 26.80 seconds, + 4.4%, P = 0.149) and BT

  8. Acute Responses to 10×15 m Repeated Sprint Ability Exercise in Adolescent Athletes: the Role of Change of Direction and Sport Specialization

    PubMed Central

    Nikolaidis, Pantelis Theodoros; Meletakos, Panagiotis; Tasiopoulos, Ioannis; Kostoulas, Ioannis; Ganavias, Panagiotis

    2016-01-01

    Background The repeated sprint ability (RSA) has been studied with protocols using distances longer than 20 m per sprint, whereas basketball players cover on average less than 20-meter distance per sprint during match. Objectives The aim of the present study was to examine the physiological impact of 10 × 15 m RSA test in straight-line (RSASL) or with change of direction (RSACOD), i.e. 10 × (7.5 + 7.5 m)) in young national level basketball players. Patients and Methods Young basketball players (n = 11, age 17.1 (1.0) years, body mass 76 (6) kg, height 184 (4) cm, body mass index 22.6 (1.8) kgm-2, sport experience 6.9 (2.7) years, mean (standard deviation)) and a control group consisting of high-school athletes (n = 7, 16.1 (0.7) years, 67 (6) kg, 177 (6) cm, 21.5 (1.0) kgm-2, 7.7 (1.6) years, respectively) performed RSASL and RSACOD on a counter-balanced order. Sprints started every 30 seconds (active recovery) and there was 30 minutes break between RSA protocols; time variables were total time (TT), best time (BT) and fatigue index (FI). Countermovement jump (CMJ) was tested before and after each RSA protocol. Heart rate (HR) was continuously monitored during testing procedures. Results Compared with RSASL, TT and BT were worst in RSACOD (38.13 vs. 27.52 s and 3.67 vs. 2.66 s, P < 0.001, respectively), whereas FI did not differ (3.8 vs. 3.5%, P = 0.388). A 2 × 2 repeated measures ANOVA showed main effect of RSA on CMJ (pre-test vs. post-test, increase + 1.8 cm, P = 0.020, η2 = 0.28); there was neither main effect of RSA protocols (RSASL vs. RSACOD +0.7 cm, P = 0.251, η2 = 0.08) nor an interaction between pre-post measurements and RSA protocols (P = 0.578, η2 = 0.02). Compared with RSASL, RSACOD induced higher mean and peak HR responses (175 vs 172 bpm, P < 0.001, and 185 vs 182 bpm, P = 0.002, respectively). No statistical difference was observed between basketball players and control group neither for TT (27.98 vs. 26.80 seconds, + 4.4%, P = 0.149) and BT

  9. Physiological characteristics of well-trained junior sprint kayak athletes.

    PubMed

    Borges, Thiago Oliveira; Dascombe, Ben; Bullock, Nicola; Coutts, Aaron J

    2015-07-01

    This study aimed to profile the physiological characteristics of junior sprint kayak athletes (n=21, VO2max 4.1±0.7 L/min, training experience 2.7±1.2 y) and to establish the relationship between physiological variables (VO2max, VO2 kinetics, muscle-oxygen kinetics, paddling efficiency) and sprint kayak performance. VO2max, power at VO2max, power:weight ratio, paddling efficiency, VO2 at lactate threshold, and whole-body and muscle oxygen kinetics were determined on a kayak ergometer in the laboratory. Separately, on-water time trials (TT) were completed over 200 m and 1000 m. Large to nearly perfect (-.5 to -.9) inverse relationships were found between the physiological variables and on-water TT performance across both distances. Paddling efficiency and lactate threshold shared moderate to very large correlations (-.4 to -.7) with 200- and 1000-m performance. In addition, trivial to large correlations (-.11 to -.5) were observed between muscle-oxygenation parameters, muscle and whole-body oxygen kinetics, and performance. Multiple regression showed that 88% of the unadjusted variance for the 200-m TT performance was explained by VO2max, peripheral muscle deoxygenation, and maximal aerobic power (P<.001), whereas 85% of the unadjusted variance in 1000-m TT performance was explained by VO2max and deoxyhemoglobin (P<.001). The current findings show that well-trained junior sprint kayak athletes possess a high level of relative aerobic fitness and highlight the importance of the peripheral muscle metabolism for sprint kayak performance, particularly in 200-m races, where finalists and nonfinalists are separated by very small margins. Such data highlight the relative aerobic-fitness variables that can be used as benchmarks for talent-identification programs or monitoring longitudinal athlete development. However, such approaches need further investigation.

  10. Athletic Engagement and Athletic Identity in Top Croatian Sprint Runners.

    PubMed

    Babić, Vesna; Sarac, Jelena; Missoni, Sasa; Sindik, Josko

    2015-09-01

    The aim of the research was to determine construct validity and reliability for two questionnaires (Athlete Engagement Questionnaire-AEQ and Athletic Identity Measurement Scale-AIMS), applied on elite Croatian athletes-sprinters, as well as the correlations among the dimensions in these measuring instruments. Then, we have determined the differences in the dimensions of sport engagement and sport identity, according to gender, education level and winning medals on international competitions. A total of 71 elite athletes-sprinters (former and still active) are examined, from which 27 (38%) females and 44 (62%) males. The results of factor analyses revealed the existence of dimensions very similar as in the original instruments, which showed moderate to-high reliabilities. A small number of statistically significant correlations have been found between the dimensions of sport engagement and sport identity, mainly in male sprinter runners. Small number of statistically significant differences in the dimensions of sport engagement and sport identity have been found according to the gender, education level and winning medals on the international competitions. The most reasonable explanation of these differences could be given in terms of very similar characteristics of elite athletes on the same level of sport excellence.

  11. Athletic Engagement and Athletic Identity in Top Croatian Sprint Runners.

    PubMed

    Babić, Vesna; Sarac, Jelena; Missoni, Sasa; Sindik, Josko

    2015-09-01

    The aim of the research was to determine construct validity and reliability for two questionnaires (Athlete Engagement Questionnaire-AEQ and Athletic Identity Measurement Scale-AIMS), applied on elite Croatian athletes-sprinters, as well as the correlations among the dimensions in these measuring instruments. Then, we have determined the differences in the dimensions of sport engagement and sport identity, according to gender, education level and winning medals on international competitions. A total of 71 elite athletes-sprinters (former and still active) are examined, from which 27 (38%) females and 44 (62%) males. The results of factor analyses revealed the existence of dimensions very similar as in the original instruments, which showed moderate to-high reliabilities. A small number of statistically significant correlations have been found between the dimensions of sport engagement and sport identity, mainly in male sprinter runners. Small number of statistically significant differences in the dimensions of sport engagement and sport identity have been found according to the gender, education level and winning medals on the international competitions. The most reasonable explanation of these differences could be given in terms of very similar characteristics of elite athletes on the same level of sport excellence. PMID:26898045

  12. Asthma in adolescent athletes.

    PubMed

    Carlsen, Kai-Håkon; Hem, Erlend; Stensrud, Trine

    2011-12-01

    Athletes active in endurance sports are at an increased risk of acquiring asthma through their sports activities, especially so for cross-country skiers, biathlon skiers, swimmers and athletes of other endurance sports. Asthma may be present from early childhood or develop while in active sports. This article focuses on the physical activity and sports activities in children and adolescents. Exercise-induced asthma (EIA) is found in 8-10% of a normal child population of school age and in about 35% of children with current asthma. EIA is caused by the markedly increased ventilation during exercise, with increased heat and water loss through respiration, leading to bronchial constriction. The risk of developing asthma in the young athlete is related to the repeated daily training activity with increased epithelial damage of the airways, delayed repair due to the daily repetition of the training and increased airway mucosal inflammation. The increased environmental exposure through the sports activity to environmental agents, such as cold, dry air in skiers and chlorine compounds in swimmers, increases symptoms and signs of asthma and bronchial hyper-responsiveness, either worsening an existing asthma or leading to a novel disease in a previously healthy athlete. Several specific aspects of daily training life, environmental exposure, diagnostic procedures and aspects of treatment related to the regulations of medication use in sports need particular attention when addressing the adolescent athlete with respiratory symptoms.

  13. Eating Disorders in Adolescent Athletes.

    ERIC Educational Resources Information Center

    Patel, Dilip R.; Greydanus, Donald E.; Pratt, Helen D.; Phillips, Elaine L.

    2003-01-01

    Reviews research on eating disorders in adolescent athletes, including prevalence, its uncommonness among male athletes, risk factors, medical complications, prevention strategies, and implications for sport and exercise participation, management, and prognosis. (EV)

  14. Relationships between ground reaction impulse and sprint acceleration performance in team sport athletes.

    PubMed

    Kawamori, Naoki; Nosaka, Kazunori; Newton, Robert U

    2013-03-01

    Large horizontal acceleration in short sprints is a critical performance parameter for many team sport athletes. It is often stated that producing large horizontal impulse at each ground contact is essential for high short sprint performance, but the optimal pattern of horizontal and vertical impulses is not well understood, especially when the sprints are initiated from a standing start. This study was an investigation of the relationships between ground reaction impulses and sprint acceleration performance from a standing start in team sport athletes. Thirty physically active young men with team sport background performed 10-m sprint from a standing start, whereas sprint time and ground reaction forces were recorded during the first ground contact and at 8 m from the start. Associations between sprint time and ground reaction impulses (normalized to body mass) were determined by a Pearson's correlation coefficient (r) analysis. The 10-m sprint time was significantly (p < 0.01) correlated with net horizontal impulse (r = -0.52) and propulsive impulse (r = -0.66) measured at 8 m from the start. No significant correlations were found between sprint time and impulses recorded during the first ground contact after the start. These results suggest that applying ground reaction impulse in a more horizontal direction is important for sprint acceleration from a standing start. This is consistent with the hypothesis of training to increase net horizontal impulse production using sled towing or using elastic resistance devices, which needs to be validated by future longitudinal training studies.

  15. Optimizing the physical conditioning of the NASCAR sprint cup pit crew athlete.

    PubMed

    Ferguson, David P; Davis, Adam M; Lightfoot, J Timothy

    2015-03-01

    Stock car racing is the largest spectator sport in the United States. As a result, National Association for Stock Car Automobile Racing (NASCAR) Sprint Cup teams have begun to invest in strength and conditioning programs for their pit crew athletes. However, there is limited knowledge regarding the physical characteristics of elite NASCAR pit crew athletes, how the NASCAR Sprint Cup season affects basic physiological parameters such as body composition, and what is the most appropriate physical training program that meets the needs of a pit crew athlete. We conducted 3 experiments involving Sprint Cup motorsport athletes to determine predictors of success at the elite level, seasonal physiological changes, and appropriate physical training programs. Our results showed that hamstring flexibility (p = 0.015) and the score on the 2-tire front run test (p = 0.012) were significant predictors of NASCAR Sprint Cup Pit Crew athlete performance. Additionally, during the off season, pit crew athletes lost lean body mass, which did not return until the middle of the season. Therefore, a strength and conditioning program was developed to optimize pit crew athlete performance throughout the season. Implementation of this strength and conditioning program in 1 NASCAR Sprint Cup team demonstrated that pit crew athletes were able to prevent lean body mass loss and have increased muscle power output from the start of the season to the end of the season.

  16. The relationship between extension of the metatarsophalangeal joint and sprint time for 100 m Olympic athletes.

    PubMed

    Krell, Jason B; Stefanyshyn, Darren J

    2006-02-01

    Selected kinematic variables of the foot segments and the metatarsophalangeal (MTP) joint were investigated in relation to sprinting performance among 100 m sprint athletes at the 2000 Summer Olympic Games. It was hypothesized that the kinematics of the MTP joint, and forefoot and rearfoot segments, are related to sprint performance for both male and female athletes. Kinematic sagittal plane data were collected using two digital video cameras recording at 120 fields per second. It was determined that faster male sprinters experienced higher maximal rates of MTP extension, and faster female sprinters touch down with higher posterior sole angles and take off with lower posterior sole angles.

  17. Effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes.

    PubMed

    Delecluse, C; Roelants, M; Diels, R; Koninckx, E; Verschueren, S

    2005-10-01

    Despite the expanding use of Whole Body Vibration training among athletes, it is not known whether adding Whole Body Vibration training to the conventional training of sprint-trained athletes will improve speed-strength performance. Twenty experienced sprint-trained athletes (13 male symbol, 7 female symbol, 17-30 years old) were randomly assigned to a Whole Body Vibration group (n=10: 6 male symbol and 4 female symbol) or a Control group (n=10: 7 male symbol, 3 female symbol). During a 5-week experimental period all subjects continued their conventional training program, but the subjects of the Whole Body Vibration group additionally performed three times weekly a Whole Body Vibration training prior to their conventional training program. The Whole Body Vibration program consisted of unloaded static and dynamic leg exercises on a vibration platform (35-40 Hz, 1.7-2.5 mm, Power Plate). Pre and post isometric and dynamic (100 degrees/s) knee-extensor and -flexor strength and knee-extension velocity at fixed resistances were measured by means of a motor-driven dynamometer (Rev 9000, Technogym). Vertical jump performance was measured by means of a contact mat. Force-time characteristics of the start action were assessed using a load cell mounted on each starting block. Sprint running velocity was recorded by means of a laser system. Isometric and dynamic knee-extensor and knee-flexor strength were unaffected (p>0.05) in the Whole Body Vibration group and the Control group. As well, knee-extension velocity remained unchanged (p>0.05). The duration of the start action, the resulting start velocity, start acceleration, and sprint running velocity did not change (>0.05) in either group. In conclusion, this specific Whole Body Vibration protocol of 5 weeks had no surplus value upon the conventional training program to improve speed-strength performance in sprint-trained athletes. PMID:16158372

  18. Age and sex differences in blood lactate response to sprint running in elite master athletes.

    PubMed

    Korhonen, Marko T; Suominen, Harri; Mero, Antti

    2005-12-01

    The effect of age and sex on anaerobic glycolytic capacity in master athletes is currently unclear. To study this issue, we determined blood lactate concentrations after competitive sprint running in male and female master athletes of different age. Eighty-one men (40-88 yrs) and 75 women (35-87 yrs) participating in the sprint events (100-m, 200-m, 400-m) in the European Veterans Athletics Championships were studied. Blood samples were taken from the fingertip and analysed for peak lactate concentration ([La]bpeak). The [La]bpeak following 100-m to 400-m races showed a curvilinear decline (p < 0.001-0.05) with age in both men and women. However, the age related differences in the [La]b peak were not significant before 70 years of age. No significant sex related differences were found in [La]b peak for any sprint event. The [La]b peak correlated significantly (p < 0.001-0.05) with running times in all sprint distances except for the age-controlled correlation in men for the 100-m and 200-m. In conclusion, the present study showed age but not sex differences in blood lactate response to competitive sprint running in master athletes. Although the [La]b peak level of the athletes was considerably higher than that reported for untrained men and women, these cross-sectional findings suggest that anaerobic energy production from glycolysis declines in later years and may be a factor in the deterioration in sprint performance.

  19. Effects of resisted sled towing on sprint kinematics in field-sport athletes.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Spinks, Christopher D

    2003-11-01

    Weighted sled towing is a common resisted sprint training technique even though relatively little is known about the effects that such practice has on sprint kinematics. The purpose of this study was to explore the effects of sled towing on acceleration sprint kinematics in field-sport athletes. Twenty men completed a series of sprints without resistance and with loads equating to 12.6 and 32.2% of body mass. Stride length was significantly reduced by approximately 10 and approximately 24% for each load, respectively. Stride frequency also decreased, but not to the extent of stride length. In addition, sled towing increased ground contact time, trunk lean, and hip flexion. Upper-body results showed an increase in shoulder range of motion with added resistance. The heavier load generally resulted in a greater disruption to normal acceleration kinematics compared with the lighter load. The lighter load is likely best for use in a training program.

  20. The influence of parachute-resisted sprinting on running mechanics in collegiate track athletes.

    PubMed

    Paulson, Sally; Braun, William A

    2011-06-01

    The influence of parachute-resisted sprinting on running mechanics in collegiate track athletes. The aim of this investigation was to compare the acute effects of parachute-resisted (PR) sprinting on selected kinematic variables. Twelve collegiate sprinters (mean age 19.58 ± 1.44 years, mass 69.32 ± 14.38 kg, height 1.71 ± 9.86 m) ran a 40-yd dash under 2 conditions: PR sprint and sprint without a parachute (NC) that were recorded on a video computer system (60 Hz). Sagittal plane kinematics of the right side of the body was digitized to calculate joint angles at initial ground contact (IGC) and end ground contact (EGC), ground contact (GC) time, stride rate (SR), stride length (SL), and the times of the 40-yd dashes. The NC 40-yd dash time was significantly faster than the PR trial (p < 0.05). The shoulder angle at EGC significantly increased from 34.10 to 42.10° during the PR trial (p < 0.05). There were no significant differences in GC time, SR, SL, or the other joint angles between the 2 trials (p > 0.05). This study suggests that PR sprinting does not acutely affect GC time, SR, SL and upper extremity or lower extremity joint angles during weight acceptance (IGC) in collegiate sprinters. However, PR sprinting increased shoulder flexion by 23.5% at push-off and decreased speed by 4.4%. While sprinting with the parachute, the athlete's movement patterns resembled their mechanics during the unloaded condition. This indicates the external load caused by PR did not substantially overload the runner, and only caused a minor change in the shoulder during push-off. This sports-specific training apparatus may provide coaches with another method for training athletes in a sports-specific manner without causing acute changes to running mechanics.

  1. Effects of red bull energy drink on repeated sprint performance in women athletes.

    PubMed

    Astorino, Todd A; Matera, Angela J; Basinger, Jency; Evans, Mindy; Schurman, Taylor; Marquez, Rodney

    2012-05-01

    Energy drinks are frequently consumed by athletes prior to competition to improve performance. This study examined the effect of Red Bull™ on repeated sprint performance in women athletes. Fifteen collegiate soccer players participated, with mean age, height, and body mass equal to 19.5±1.1 year, 168.4±5.8 cm, and 63.4±6.1 kg, respectively. After performing a familiarization trial, subjects performed three sets of eight bouts of the modified t test after ingestion of 255 mL of placebo or Red Bull 1 h pre-exercise in a randomized, placebo-controlled crossover design. Throughout testing, sprint time, heart rate (HR), and rating of perceived exertion (RPE) were continuously obtained. Repeated measures analysis of variance was used to examine differences in variables between drink conditions. Across athletes, t test time ranged from 10.4 to 12.7 s. Mean sprint time was similar (p>0.05) between Red Bull (11.31±0.61 s) and placebo (11.35±0.61 s). HR and RPE increased (p<0.05) during the bouts, but there was no effect (p>0.05) of Red Bull on either variable versus placebo. Findings indicate that 255 mL of Red Bull containing 1.3 mg/kg of caffeine and 1 g of taurine does not alter repeated sprint performance, RPE, or HR in women athletes versus placebo. One serving of this energy drink provides no ergogenic benefit for women athletes engaging in sprint-based exercise. PMID:21461905

  2. Sprint-based exercise and cognitive function in adolescents.

    PubMed

    Cooper, Simon B; Bandelow, Stephan; Nute, Maria L; Dring, Karah J; Stannard, Rebecca L; Morris, John G; Nevill, Mary E

    2016-12-01

    Moderate intensity exercise has been shown to enhance cognition in an adolescent population, yet the effect of high-intensity sprint-based exercise remains unknown and was therefore examined in the present study. Following ethical approval and familiarisation, 44 adolescents (12.6 ± 0.6 y) completed an exercise (E) and resting (R) trial in a counter-balanced, randomised crossover design. The exercise trial comprised of 10 × 10 s running sprints, interspersed by 50 s active recovery (walking). A battery of cognitive function tests (Stroop, Digit Symbol Substitution (DSST) and Corsi blocks tests) were completed 30 min pre-exercise, immediately post-exercise and 45 min post-exercise. Data were analysed using mixed effect models with repeated measures. Response times on the simple level of the Stroop test were significantly quicker 45 min following sprint-based exercise (R: 818 ± 33 ms, E: 772 ± 26 ms; p = 0.027) and response times on the complex level of the Stroop test were quicker immediately following the sprint-based exercise (R: 1095 ± 36 ms, E: 1043 ± 37 ms; p = 0.038), while accuracy was maintained. Sprint-based exercise had no immediate or delayed effects on the number of items recalled on the Corsi blocks test (p = 0.289) or substitutions made during the DSST (p = 0.689). The effect of high intensity sprint-based exercise on adolescents' cognitive function was dependant on the component of cognitive function examined. Executive function was enhanced following exercise, demonstrated by improved response times on the Stroop test, whilst visuo-spatial memory and general psycho-motor speed were unaffected. These data support the inclusion of high-intensity sprint-based exercise for adolescents during the school day to enhance cognition. PMID:27413677

  3. Sprint-based exercise and cognitive function in adolescents.

    PubMed

    Cooper, Simon B; Bandelow, Stephan; Nute, Maria L; Dring, Karah J; Stannard, Rebecca L; Morris, John G; Nevill, Mary E

    2016-12-01

    Moderate intensity exercise has been shown to enhance cognition in an adolescent population, yet the effect of high-intensity sprint-based exercise remains unknown and was therefore examined in the present study. Following ethical approval and familiarisation, 44 adolescents (12.6 ± 0.6 y) completed an exercise (E) and resting (R) trial in a counter-balanced, randomised crossover design. The exercise trial comprised of 10 × 10 s running sprints, interspersed by 50 s active recovery (walking). A battery of cognitive function tests (Stroop, Digit Symbol Substitution (DSST) and Corsi blocks tests) were completed 30 min pre-exercise, immediately post-exercise and 45 min post-exercise. Data were analysed using mixed effect models with repeated measures. Response times on the simple level of the Stroop test were significantly quicker 45 min following sprint-based exercise (R: 818 ± 33 ms, E: 772 ± 26 ms; p = 0.027) and response times on the complex level of the Stroop test were quicker immediately following the sprint-based exercise (R: 1095 ± 36 ms, E: 1043 ± 37 ms; p = 0.038), while accuracy was maintained. Sprint-based exercise had no immediate or delayed effects on the number of items recalled on the Corsi blocks test (p = 0.289) or substitutions made during the DSST (p = 0.689). The effect of high intensity sprint-based exercise on adolescents' cognitive function was dependant on the component of cognitive function examined. Executive function was enhanced following exercise, demonstrated by improved response times on the Stroop test, whilst visuo-spatial memory and general psycho-motor speed were unaffected. These data support the inclusion of high-intensity sprint-based exercise for adolescents during the school day to enhance cognition.

  4. The effect of heavy resistance exercise on repeated sprint performance in youth athletes.

    PubMed

    Low, Daniel; Harsley, Paul; Shaw, Matthew; Peart, Daniel

    2015-01-01

    This investigation assessed whether prior heavy resistance exercise would improve the repeated sprint performance of 16 trained youth soccer players (Age 17.05 ± 0.65 years; height 182.6 ± 8.9 cm; body mass 77.8 ± 8.2 kg). In session 1, individual 1 repetition max was measured utilising a squat movement. In sessions 2 and 3, participants performed a running-based repeated anaerobic sprint test with and without prior heavy resistance exercise of 91% of their 1 repetition max. Times were recorded for each of the 6 sprints performed in the repeated sprint test and summed to provide total time. T-tests compared the two exercise conditions via differences in corresponding sprint times and total time. Analysis revealed significantly reduced total time with use of heavy resistance exercise (33.48 (±1.27) vs. 33.59 (±1.27); P = 0.01). Sprints 1 (P = 0.05) and 2 (P = 0.02) were also faster in the heavy resistance exercise condition (5.09 (±0.16) vs. 5.11 (±0.16) and 5.36 (±0.24) vs. 5.45 (±0.26) seconds respectively) although no other differences were shown. Findings demonstrate improved sprint times of trained adolescent soccer players after heavy resistance exercise although benefits appear not as sustained as in adult participants.

  5. Paraoxonase activity in athletic adolescents.

    PubMed

    Cakmak, Alpay; Zeyrek, Dost; Atas, Ali; Erel, Ozcan

    2010-02-01

    Regular physical activity may play a protective role against cardiovascular disease in adults, and paraoxonase activity may serve to mediate this effect. This study compared paraoxonase activity and that of other antioxidative agents in adolescent athletes compared with inactive youth. Paraoxonase level was 177.32 +/- 100.10 (U/L) in children with regular physical activity and 98.11 +/- 40.92 (U/L) in the control group (P < 0.0001). The levels of total antioxidative capacity, total oxidative status, oxidative stress index, and lipid hydroperoxide were significantly higher in the athlete group compared with controls (P < 0.0001). Paraoxonase activity was found to be greater in adolescent athletes, suggesting that regular exercise might provide a cardio-protective effect by this means.

  6. Five Weeks of Sprint and High-Intensity Interval Training Improves Paddling Performance in Adolescent Surfers.

    PubMed

    Farley, Oliver R L; Secomb, Josh L; Parsonage, Joanna R; Lundgren, Lina E; Abbiss, Chris R; Sheppard, Jeremy M

    2016-09-01

    Farley, ORL, Secomb, JL, Parsonage, JR, Lundgren, LE, Abbiss, CR, and Sheppard, JM. Five weeks of sprint and high-intensity interval training improves paddling performance in adolescent surfers. J Strength Cond Res 30(9): 2446-2452, 2016-The purpose of our study was to examine the effects of sprint interval training (SIT; 10 seconds) and high-intensity interval training (HIT; 30 seconds) on surfing athletes paddling performance (400-m time trial and repeat-sprint paddle performance). Twenty-four competitive adolescent surfers (19 male, 5 female; age = 14.4 ± 1.3 years, mass: 50.1 ± 10.7 kg, and stature: 159.9 ± 10.3 cm) were assigned to perform either 5 weeks of SIT and HIT. Participants completed a repeated-sprint paddle ability test (RSPT, 15-m surfboard sprint paddle initiated every 40 seconds × 10 bouts) and 400-m endurance surfboard paddle time trial before and after training. High-intensity interval training decreased the total time to complete the 400 m by 15.8 ± 16.1 seconds (p = 0.03), and SIT decreased the total time to complete the RSPT by 6.5 ± 4.3 seconds (p = 0.02). Fatigue index during the RSPT (first-slowest effort) was lower after HIT and SIT (p ≤ 0.001 and p = 0.02, respectively). There were no significant differences in performance changes in the 400 m (total time) and RSPT (total time, fastest 15 m time, and peak velocity) between HIT and SIT. Our study indicates that HIT and SIT may be implemented to the training program of surfers to improve aerobic and repeat-sprint paddle ability, both of which are identified as key aspects of the sport. In addition, these findings indicate that 400-m paddle and RSPT can discriminate between aerobic and anaerobic training adaptations, with aerobic gains likely from HIT and anaerobic gains from SIT. PMID:26849794

  7. Five Weeks of Sprint and High-Intensity Interval Training Improves Paddling Performance in Adolescent Surfers.

    PubMed

    Farley, Oliver R L; Secomb, Josh L; Parsonage, Joanna R; Lundgren, Lina E; Abbiss, Chris R; Sheppard, Jeremy M

    2016-09-01

    Farley, ORL, Secomb, JL, Parsonage, JR, Lundgren, LE, Abbiss, CR, and Sheppard, JM. Five weeks of sprint and high-intensity interval training improves paddling performance in adolescent surfers. J Strength Cond Res 30(9): 2446-2452, 2016-The purpose of our study was to examine the effects of sprint interval training (SIT; 10 seconds) and high-intensity interval training (HIT; 30 seconds) on surfing athletes paddling performance (400-m time trial and repeat-sprint paddle performance). Twenty-four competitive adolescent surfers (19 male, 5 female; age = 14.4 ± 1.3 years, mass: 50.1 ± 10.7 kg, and stature: 159.9 ± 10.3 cm) were assigned to perform either 5 weeks of SIT and HIT. Participants completed a repeated-sprint paddle ability test (RSPT, 15-m surfboard sprint paddle initiated every 40 seconds × 10 bouts) and 400-m endurance surfboard paddle time trial before and after training. High-intensity interval training decreased the total time to complete the 400 m by 15.8 ± 16.1 seconds (p = 0.03), and SIT decreased the total time to complete the RSPT by 6.5 ± 4.3 seconds (p = 0.02). Fatigue index during the RSPT (first-slowest effort) was lower after HIT and SIT (p ≤ 0.001 and p = 0.02, respectively). There were no significant differences in performance changes in the 400 m (total time) and RSPT (total time, fastest 15 m time, and peak velocity) between HIT and SIT. Our study indicates that HIT and SIT may be implemented to the training program of surfers to improve aerobic and repeat-sprint paddle ability, both of which are identified as key aspects of the sport. In addition, these findings indicate that 400-m paddle and RSPT can discriminate between aerobic and anaerobic training adaptations, with aerobic gains likely from HIT and anaerobic gains from SIT.

  8. Sex alters impact of repeated bouts of sprint exercise on neuromuscular activity in trained athletes.

    PubMed

    Billaut, François; Smith, Kurt

    2009-08-01

    This study characterized the effect of sex on neuromuscular activity during repeated bouts of sprint exercise. Thirty-three healthy male and female athletes performed twenty 5-s cycle sprints separated by 25 s of rest. Mechanical work and integrated electromyograhs (iEMG) of 4 muscles of the dominant lower limb were calculated in every sprint. The iEMG signals from individual muscles were summed to represent overall electrical activity of these muscles (sum-iEMG). Neuromuscular efficiency (NME) was calculated as the ratio of mechanical work and sum-iEMG for every sprint. Arterial oxygen saturation was estimated (SpO2) with pulse oximetry throughout the protocol. The sprint-induced work decrement (18.9% vs. 29.6%; p < 0.05) and sum-iEMG reduction (11.4% vs. 19.4%; p < 0.05) were less for the women than for the men. However, the sprints decreased NME (10.1%; p < 0.05) and SpO2 (3.4%; p < 0.05) without showing sex dimorphism. Changes in SpO2 and sum-iEMG were strongly correlated in both sexes (men, R2 = 0.87; women, R2 = 0.91; all p < 0.05), although the slope of this relationship differed (6.3 +/- 2.9 vs. 3.8 +/- 1.6, respectively; p < 0.05). It is suggested that the sex difference in fatigue during repeated bouts of sprint exercise is not likely to be explained by a difference in muscle contractility impairment in men and women, but may be due to a sex difference in muscle recruitment strategy. We speculate that women would be less sensitive to arterial O2 desaturation than men, which may trigger lower neuromuscular adjustments to exhaustive exercise.

  9. Sprint mechanics in world-class athletes: a new insight into the limits of human locomotion.

    PubMed

    Rabita, G; Dorel, S; Slawinski, J; Sàez-de-Villarreal, E; Couturier, A; Samozino, P; Morin, J-B

    2015-10-01

    The objective of this study was to characterize the mechanics of maximal running sprint acceleration in high-level athletes. Four elite (100-m best time 9.95-10.29 s) and five sub-elite (10.40-10.60 s) sprinters performed seven sprints in overground conditions. A single virtual 40-m sprint was reconstructed and kinetics parameters were calculated for each step using a force platform system and video analyses. Anteroposterior force (FY), power (PY), and the ratio of the horizontal force component to the resultant (total) force (RF, which reflects the orientation of the resultant ground reaction force for each support phase) were computed as a function of velocity (V). FY-V, RF-V, and PY-V relationships were well described by significant linear (mean R(2) of 0.892 ± 0.049 and 0.950 ± 0.023) and quadratic (mean R(2) = 0.732 ± 0.114) models, respectively. The current study allows a better understanding of the mechanics of the sprint acceleration notably by modeling the relationships between the forward velocity and the main mechanical key variables of the sprint. As these findings partly concern world-class sprinters tested in overground conditions, they give new insights into some aspects of the biomechanical limits of human locomotion.

  10. Influence of sprint acceleration stance kinetics on velocity and step kinematics in field sport athletes.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Schultz, Adrian B; Jeffriess, Matthew D; Callaghan, Samuel J

    2013-09-01

    The interaction between step kinematics and stance kinetics determines sprint velocity. However, the influence that stance kinetics has on effective acceleration in field sport athletes requires clarification. About 25 men (age = 22.4 ± 3.2 years; mass = 82.8 ± 7.2 kg; height = 1.81 ± 0.07 m) completed twelve 10-m sprints, 6 sprints each for kinematic and kinetic assessment. Pearson's correlations (p ≤ 0.05) examined relationships between 0-5, 5-10, and 0-10 m velocity; step kinematics (mean step length [SL], step frequency, contact time [CT], flight time over each interval); and stance kinetics (relative vertical, horizontal, and resultant force and impulse; resultant force angle; ratio of horizontal to resultant force [RatF] for the first, second, and last contacts within the 10-m sprint). Relationships were found between 0-5, 5-10, and 0-10 m SL and 0-5 and 0-10 m velocity (r = 0.397-0.535). CT of 0-5 and 0-10 m correlated with 5-10 m velocity (r = -0.506 and -0.477, respectively). Last contact vertical force correlated with 5-10 m velocity (r = 0.405). Relationships were established between the second and last contact vertical and resultant force and CT over all intervals (r = -0.398 to 0.569). First and second contact vertical impulse correlated with 0-5 m SL (r = 0.434 and 0.442, respectively). Subjects produced resultant force angles and RatF suitable for horizontal force production. Faster acceleration in field sport athletes involved longer steps, with shorter CT. Greater vertical force production was linked with shorter CT, illustrating efficient force production. Greater SLs during acceleration were facilitated by higher vertical impulse and appropriate horizontal force. Speed training for field sport athletes should be tailored to encourage these technique adaptations.

  11. Acute Effects of Loaded Half-Squat Jumps on Sprint Running Speed in Track and Field Athletes and Soccer Players.

    PubMed

    Vanderka, Marián; Krčmár, Matúš; Longová, Katarína; Walker, Simon

    2016-06-01

    Vanderka, M, Krčmár, M, Longová, K, and Walker, S. Acute effects of loaded half-squat jumps on sprint running speed in track and field athletes and soccer players. J Strength Cond Res 30(6): 1540-1546, 2016-The purpose of the study was to determine the acute responses to a jump squat protocol designed to induce postactivation potentiation on sprint running performance in experienced track and field athletes and soccer players. Twenty-five regional level athletes (12 track and field: ∼17 years; ∼177 cm; ∼73 kg and 13 soccer: ∼18 years; ∼175 cm; ∼72 kg) performed 2 test sessions assessing 40-m sprint running performance in a balanced, crossover design. Dual-beam light timing gates measured 0-20 and 20-40 m sprint times before and after either 9 minutes of sitting (control) or 2 sets of 6 repetition half-squat jump with the load eliciting maximum power (experimental) conditions. Sprint performance was significantly enhanced over both 0-20 m (3.09 ± 0.07 to 3.04 ± 0.08 seconds; Δ ∼1.5%; p ≤ 0.05) and 20-40 m (2.42 ± 0.09 to 2.39 ± 0.09 seconds; Δ ∼1%; p ≤ 0.05) in track and field athletes only. Also, the magnitude of enhanced sprint performance was related to baseline 0-20 m sprint performance (r = 0.44; p = 0.028; n = 25). It seems that using loaded half-squat jumps to enhance sprint performance could be used in training of high-level young athletes.

  12. Acute Effects of Loaded Half-Squat Jumps on Sprint Running Speed in Track and Field Athletes and Soccer Players.

    PubMed

    Vanderka, Marián; Krčmár, Matúš; Longová, Katarína; Walker, Simon

    2016-06-01

    Vanderka, M, Krčmár, M, Longová, K, and Walker, S. Acute effects of loaded half-squat jumps on sprint running speed in track and field athletes and soccer players. J Strength Cond Res 30(6): 1540-1546, 2016-The purpose of the study was to determine the acute responses to a jump squat protocol designed to induce postactivation potentiation on sprint running performance in experienced track and field athletes and soccer players. Twenty-five regional level athletes (12 track and field: ∼17 years; ∼177 cm; ∼73 kg and 13 soccer: ∼18 years; ∼175 cm; ∼72 kg) performed 2 test sessions assessing 40-m sprint running performance in a balanced, crossover design. Dual-beam light timing gates measured 0-20 and 20-40 m sprint times before and after either 9 minutes of sitting (control) or 2 sets of 6 repetition half-squat jump with the load eliciting maximum power (experimental) conditions. Sprint performance was significantly enhanced over both 0-20 m (3.09 ± 0.07 to 3.04 ± 0.08 seconds; Δ ∼1.5%; p ≤ 0.05) and 20-40 m (2.42 ± 0.09 to 2.39 ± 0.09 seconds; Δ ∼1%; p ≤ 0.05) in track and field athletes only. Also, the magnitude of enhanced sprint performance was related to baseline 0-20 m sprint performance (r = 0.44; p = 0.028; n = 25). It seems that using loaded half-squat jumps to enhance sprint performance could be used in training of high-level young athletes. PMID:26562707

  13. A Clustered Repeated-Sprint Running Protocol for Team-Sport Athletes Performed in Normobaric Hypoxia

    PubMed Central

    Morrison, Jaime; McLellan, Chris; Minahan, Clare

    2015-01-01

    The present study compared the performance (peak speed, distance, and acceleration) of ten amateur team-sport athletes during a clustered (i.e., multiple sets) repeated-sprint protocol, (4 sets of 4, 4-s running sprints; i.e., RSR444) in normobaric normoxia (FiO2 = 0.209; i.e., RSN) with normobaric hypoxia (FiO2 = 0.140; i.e., RSH). Subjects completed two separate trials (i. RSN, ii. RSH; randomised order) between 48 h and 72 h apart on a non-motorized treadmill. In addition to performance, we examined blood lactate concentration [La-] and arterial oxygen saturation (SpO2) before, during, and after the RSR444. While there were no differences in peak speed or distance during set 1 or set 2, peak speed (p = 0.04 and 0.02, respectively) and distance (p = 0.04 and 0.02, respectively) were greater during set 3 and set 4 of RSN compared with RSH. There was no difference in the average acceleration achieved in set 1 (p = 0.45), set 2 (p = 0.26), or set 3 (p = 0.23) between RSN and RSH; however, the average acceleration was greater in RSN than RSH in set 4 (p < 0.01). Measurements of [La-] were higher during RSH than RSN immediately after Sprint 16 (10.2 ± 2.5 vs 8.6 ± 2.6 mM; p = 0.02). Estimations of SpO2 were lower during RSH than RSN, respectively, immediately prior to the commencement of the test (89.0 ± 2.0 vs 97.2 ± 1.5 %), post Sprint 8 (78.0 ± 6.3 vs 93.8 ± 3.6 %) and post Sprint 16 (75.3 ± 6.3 vs 94.5 ± 2.5 %; all p < 0.01). In summary, the RSR444 is a practical protocol for the implementation of a hypoxic repeated-sprint training intervention into the training schedules of team-sport athletes. However, given the inability of amateur team-sport athletes to maintain performance in hypoxic (FiO2 = 0.140) conditions, the potential for specific training outcomes (i.e. speed) to be achieved will be compromised, thus suggesting that the RSR444 should be used with caution. Key points The RSR444 is a practical, multiple-set repeated-sprint running protocol

  14. A Clustered Repeated-Sprint Running Protocol for Team-Sport Athletes Performed in Normobaric Hypoxia.

    PubMed

    Morrison, Jaime; McLellan, Chris; Minahan, Clare

    2015-12-01

    The present study compared the performance (peak speed, distance, and acceleration) of ten amateur team-sport athletes during a clustered (i.e., multiple sets) repeated-sprint protocol, (4 sets of 4, 4-s running sprints; i.e., RSR444) in normobaric normoxia (FiO2 = 0.209; i.e., RSN) with normobaric hypoxia (FiO2 = 0.140; i.e., RSH). Subjects completed two separate trials (i. RSN, ii. RSH; randomised order) between 48 h and 72 h apart on a non-motorized treadmill. In addition to performance, we examined blood lactate concentration [La(-)] and arterial oxygen saturation (SpO2) before, during, and after the RSR444. While there were no differences in peak speed or distance during set 1 or set 2, peak speed (p = 0.04 and 0.02, respectively) and distance (p = 0.04 and 0.02, respectively) were greater during set 3 and set 4 of RSN compared with RSH. There was no difference in the average acceleration achieved in set 1 (p = 0.45), set 2 (p = 0.26), or set 3 (p = 0.23) between RSN and RSH; however, the average acceleration was greater in RSN than RSH in set 4 (p < 0.01). Measurements of [La(-)] were higher during RSH than RSN immediately after Sprint 16 (10.2 ± 2.5 vs 8.6 ± 2.6 mM; p = 0.02). Estimations of SpO2 were lower during RSH than RSN, respectively, immediately prior to the commencement of the test (89.0 ± 2.0 vs 97.2 ± 1.5 %), post Sprint 8 (78.0 ± 6.3 vs 93.8 ± 3.6 %) and post Sprint 16 (75.3 ± 6.3 vs 94.5 ± 2.5 %; all p < 0.01). In summary, the RSR444 is a practical protocol for the implementation of a hypoxic repeated-sprint training intervention into the training schedules of team-sport athletes. However, given the inability of amateur team-sport athletes to maintain performance in hypoxic (FiO2 = 0.140) conditions, the potential for specific training outcomes (i.e. speed) to be achieved will be compromised, thus suggesting that the RSR444 should be used with caution. Key pointsThe RSR444 is a practical, multiple-set repeated-sprint running protocol

  15. Sports injuries and adolescent athletes.

    PubMed

    Axe, M J; Newcomb, W A; Warner, D

    1991-06-01

    A one-year study was undertaken investigating adolescent sports injury experiences at a major sports clinic in the state of Delaware. A total of 619 athletes sustained 870 injuries, for an overall injury rate of 1.4 injuries per athlete. The largest number of injuries was recorded in football (40.2 percent), followed by boys' soccer, wrestling, baseball and girls' basketball. Severity of injury was measured by the number of days lost per injury. Cheerleading had the highest average days lost per injury (28.8), followed by girls' basketball, wrestling, boys' cross-country and girls' tennis. Inflammation, fractures and dislocations comprised 50.6 percent of all the injuries, while 50.5 percent of the injuries were located in the knee, thigh, and shoulder. Twenty-seven of the 870 injuries required surgery. PMID:1874345

  16. Sports injuries and adolescent athletes.

    PubMed

    Axe, M J; Newcomb, W A; Warner, D

    1991-06-01

    A one-year study was undertaken investigating adolescent sports injury experiences at a major sports clinic in the state of Delaware. A total of 619 athletes sustained 870 injuries, for an overall injury rate of 1.4 injuries per athlete. The largest number of injuries was recorded in football (40.2 percent), followed by boys' soccer, wrestling, baseball and girls' basketball. Severity of injury was measured by the number of days lost per injury. Cheerleading had the highest average days lost per injury (28.8), followed by girls' basketball, wrestling, boys' cross-country and girls' tennis. Inflammation, fractures and dislocations comprised 50.6 percent of all the injuries, while 50.5 percent of the injuries were located in the knee, thigh, and shoulder. Twenty-seven of the 870 injuries required surgery.

  17. Aerobic and anaerobic determinants of repeated sprint ability in team sports athletes.

    PubMed

    Gharbi, Z; Dardouri, W; Haj-Sassi, R; Chamari, K; Souissi, N

    2015-09-01

    The aim of this study was to examine in team sports athletes the relationship between repeated sprint ability (RSA) indices and both aerobic and anaerobic fitness components. Sixteen team-sport players were included (age, 23.4 ± 2.3 years; weight, 71.2 ± 8.3 kg; height, 178 ± 7 cm; body mass index, 22.4 ± 2 kg · m(-2); estimated VO2max, 54.16 ± 3.5 mL · kg(-1) · min(-1)). Subjects were licensed in various team sports: soccer (n = 8), basketball (n = 5), and handball (n = 3). They performed 4 tests: the 20 m multi-stage shuttle run test (MSRT), the 30-s Wingate test (WingT), the Maximal Anaerobic Shuttle Running Test (MASRT), and the RSA test (10 repetitions of 30 m shuttle sprints (15 + 15 m with 180° change of direction) with 30 s passive recovery in between). Pearson's product moment of correlation among the different physical tests was performed. No significant correlations were found between any RSA test indices and WingT. However, negative correlations were found between MASRT and RSA total sprint time (TT) and fatigue index (FI) (r = -0.53, p < 0.05 and r = -0.65, p < 0.01, respectively). No significant relationship between VO2max and RSA peak sprint time (PT) and total sprint time (TT) was found. Nevertheless, VO2max was significantly correlated with the RSA FI (r = -0.57, p < 0.05). In conclusion, aerobic fitness is an important factor influencing the ability to resist fatigue during RSA exercise. Our results highlighted the usefulness of MASRT, in contrast to WingT, as a specific anaerobic testing procedure to identify the anaerobic energy system contribution during RSA. PMID:26424923

  18. Aerobic and anaerobic determinants of repeated sprint ability in team sports athletes

    PubMed Central

    Dardouri, W; Haj-Sassi, R; Chamari, K; Souissi, N

    2015-01-01

    The aim of this study was to examine in team sports athletes the relationship between repeated sprint ability (RSA) indices and both aerobic and anaerobic fitness components. Sixteen team-sport players were included (age, 23.4 ± 2.3 years; weight, 71.2 ± 8.3 kg; height, 178 ± 7 cm; body mass index, 22.4 ± 2 kg · m−2; estimated VO2max, 54.16 ± 3.5 mL · kg−1 · min−1). Subjects were licensed in various team sports: soccer (n = 8), basketball (n = 5), and handball (n = 3). They performed 4 tests: the 20 m multi-stage shuttle run test (MSRT), the 30-s Wingate test (WingT), the Maximal Anaerobic Shuttle Running Test (MASRT), and the RSA test (10 repetitions of 30 m shuttle sprints (15 + 15 m with 180° change of direction) with 30 s passive recovery in between). Pearson's product moment of correlation among the different physical tests was performed. No significant correlations were found between any RSA test indices and WingT. However, negative correlations were found between MASRT and RSA total sprint time (TT) and fatigue index (FI) (r = -0.53, p < 0.05 and r = -0.65, p < 0.01, respectively). No significant relationship between VO2max and RSA peak sprint time (PT) and total sprint time (TT) was found. Nevertheless, VO2max was significantly correlated with the RSA FI (r = -0.57, p < 0.05). In conclusion, aerobic fitness is an important factor influencing the ability to resist fatigue during RSA exercise. Our results highlighted the usefulness of MASRT, in contrast to WingT, as a specific anaerobic testing procedure to identify the anaerobic energy system contribution during RSA. PMID:26424923

  19. Aerobic and anaerobic determinants of repeated sprint ability in team sports athletes.

    PubMed

    Gharbi, Z; Dardouri, W; Haj-Sassi, R; Chamari, K; Souissi, N

    2015-09-01

    The aim of this study was to examine in team sports athletes the relationship between repeated sprint ability (RSA) indices and both aerobic and anaerobic fitness components. Sixteen team-sport players were included (age, 23.4 ± 2.3 years; weight, 71.2 ± 8.3 kg; height, 178 ± 7 cm; body mass index, 22.4 ± 2 kg · m(-2); estimated VO2max, 54.16 ± 3.5 mL · kg(-1) · min(-1)). Subjects were licensed in various team sports: soccer (n = 8), basketball (n = 5), and handball (n = 3). They performed 4 tests: the 20 m multi-stage shuttle run test (MSRT), the 30-s Wingate test (WingT), the Maximal Anaerobic Shuttle Running Test (MASRT), and the RSA test (10 repetitions of 30 m shuttle sprints (15 + 15 m with 180° change of direction) with 30 s passive recovery in between). Pearson's product moment of correlation among the different physical tests was performed. No significant correlations were found between any RSA test indices and WingT. However, negative correlations were found between MASRT and RSA total sprint time (TT) and fatigue index (FI) (r = -0.53, p < 0.05 and r = -0.65, p < 0.01, respectively). No significant relationship between VO2max and RSA peak sprint time (PT) and total sprint time (TT) was found. Nevertheless, VO2max was significantly correlated with the RSA FI (r = -0.57, p < 0.05). In conclusion, aerobic fitness is an important factor influencing the ability to resist fatigue during RSA exercise. Our results highlighted the usefulness of MASRT, in contrast to WingT, as a specific anaerobic testing procedure to identify the anaerobic energy system contribution during RSA.

  20. The adolescent athlete and ergogenic aids.

    PubMed

    Dyment, P G

    1987-01-01

    Amphetamines and anabolic/androgenic steroids are the ergogenic aids with the most serious side effects that adolescents are likely to misuse, although adolescents are more frequently lured into taking expensive and worthless vitamin and protein supplements. Physicians performing preparticipation physical examinations should address the issue of ergogenic aids when they offer anticipatory guidance to adolescent athletes.

  1. Acute consumption of p-synephrine does not enhance performance in sprint athletes.

    PubMed

    Gutiérrez-Hellín, Jorge; Salinero, Juan José; Abían-Vicen, Javier; Areces, Francisco; Lara, Beatriz; Gallo, Cesar; Puente, Carlos; Del Coso, Juan

    2016-01-01

    P-Synephrine is a protoalkaloid widely used as an ergogenic aid in sports. This substance has been included in the World Anti-Doping Agency monitoring program, although scientific information about its effects on performance and athletes' well-being is scarce. The purpose of this investigation was to determine the effectiveness of p-synephrine to increase performance in sprint athletes. In a randomized and counterbalanced order, 13 experienced sprinters performed 2 acute experimental trials after the ingestion of p-synephrine (3 mg·kg(-1)) or after the ingestion of a placebo (control trial). Forty-five minutes after the ingestion of the substances, the sprinters performed a squat jump, a countermovement jump, a 15-s repeated jump test, and subsequently performed 60-m and 100-m simulated sprint competitions. Self-reported questionnaires were used to assess side-effect prevalence. In comparison with the control trial, the ingestion of p-synephrine did not change countermovement jump height (37.4 ± 4.2 vs 36.7 ± 3.3 cm, respectively; P = 0.52), squat jump height (34.4 ± 3.6 vs 33.9 ± 3.7 cm; P = 0.34), or average 15-s repeated jumps height (31.8 ± 4.1 vs 32.2 ± 3.6 cm; P = 0.18). P-Synephrine did not modify maximal running speed during the 60-m (9.0 ± 0.5 vs 9.0 ± 0.4 m·s(-1), respectively; P = 0.55) and 100-m sprint competitions (8.8 ± 0.5 vs 8.8 ± 0.5 m·s(-1), respectively; P = 0.92). The ingestion of p-synephrine did not alter the prevalence of headache, gastrointestinal discomforts, muscle pain, or insomnia during the hours following the tests. Acute consumption of 3 mg·kg(-1) of p-synephrine was ineffective to increase performance in competitive sprint athletes. Moreover, p-synephrine did not increase the occurrence of side effects after the competition.

  2. Acute effect of a complex training protocol of back squats on 30-m sprint times of elite male military athletes

    PubMed Central

    Ojeda, Álvaro Huerta; Ríos, Luis Chirosa; Barrilao, Rafael Guisado; Serrano, Pablo Cáceres

    2016-01-01

    [Purpose] The aim of this study was to determine the acute effect temporal of a complex training protocol on 30 meter sprint times. A secondary objective was to evaluate the fatigue indexes of military athletes. [Subjects and Methods] Seven military athletes were the subjects of this study. The variables measured were times in 30-meter sprint, and average power and peak power of squats. The intervention session with complex training consisted of 4 sets of 5 repetitions at 30% 1RM + 4 repetitions at 60% 1RM + 3 repetitions of 30 meters with 120-second rests. For the statistical analysis repeated measures of ANOVA was used, and for the post hoc analysis, student’s t-test was used. [Results] Times in 30 meter sprints showed a significant reduction between the control set and the four experimental sets, but the average power and peak power of squats did not show significant changes. [Conclusion] The results of the study show the acute positive effect of complex training, over time, in 30-meter sprint by military athletes. This effect is due to the post activation potentiation of the lower limbs’ muscles in the 30 meters sprint. PMID:27134353

  3. Acute effect of a complex training protocol of back squats on 30-m sprint times of elite male military athletes.

    PubMed

    Ojeda, Álvaro Huerta; Ríos, Luis Chirosa; Barrilao, Rafael Guisado; Serrano, Pablo Cáceres

    2016-03-01

    [Purpose] The aim of this study was to determine the acute effect temporal of a complex training protocol on 30 meter sprint times. A secondary objective was to evaluate the fatigue indexes of military athletes. [Subjects and Methods] Seven military athletes were the subjects of this study. The variables measured were times in 30-meter sprint, and average power and peak power of squats. The intervention session with complex training consisted of 4 sets of 5 repetitions at 30% 1RM + 4 repetitions at 60% 1RM + 3 repetitions of 30 meters with 120-second rests. For the statistical analysis repeated measures of ANOVA was used, and for the post hoc analysis, student's t-test was used. [Results] Times in 30 meter sprints showed a significant reduction between the control set and the four experimental sets, but the average power and peak power of squats did not show significant changes. [Conclusion] The results of the study show the acute positive effect of complex training, over time, in 30-meter sprint by military athletes. This effect is due to the post activation potentiation of the lower limbs' muscles in the 30 meters sprint. PMID:27134353

  4. Global positioning system data analysis: velocity ranges and a new definition of sprinting for field sport athletes.

    PubMed

    Dwyer, Dan B; Gabbett, Tim J

    2012-03-01

    Global positioning system (GPS) technology has improved the speed, accuracy, and ease of time-motion analyses of field sport athletes. The large volume of numerical data generated by GPS technology is usually summarized by reporting the distance traveled and time spent in various locomotor categories (e.g., walking, jogging, and running). There are a variety of definitions used in the literature to represent these categories, which makes it nearly impossible to compare findings among studies. The purpose of this work was to propose standard definitions (velocity ranges) that were determined by an objective analysis of time-motion data. In addition, we discuss the limitations of the existing definition of a sprint and present a new definition of sprinting for field sport athletes. Twenty-five GPS data files collected from 5 different sports (men's and women's field hockey, men's and women's soccer, and Australian Rules Football) were analyzed to identify the average velocity distribution. A curve fitting process was then used to determine the optimal placement of 4 Gaussian curves representing the typical locomotor categories. Based on the findings of these analyses, we make recommendations about sport-specific velocity ranges to be used in future time-motion studies of field sport athletes. We also suggest that a sprint be defined as any movement that reaches or exceeds the sprint threshold velocity for at least 1 second and any movement with an acceleration that occurs within the highest 5% of accelerations found in the corresponding velocity range. From a practical perspective, these analyses provide conditioning coaches with information on the high-intensity sprinting demands of field sport athletes, while also providing a novel method of capturing maximal effort, short-duration sprints.

  5. The effects of different speed training protocols on sprint acceleration kinematics and muscle strength and power in field sport athletes.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Schultz, Adrian B; Knight, Timothy J; Janse de Jonge, Xanne A K

    2012-06-01

    A variety of resistance training interventions are used to improve field sport acceleration (e.g., free sprinting, weights, plyometrics, resisted sprinting). The effects these protocols have on acceleration performance and components of sprint technique have not been clearly defined in the literature. This study assessed 4 common protocols (free sprint training [FST], weight training [WT], plyometric training [PT], and resisted sprint training [RST]) for changes in acceleration kinematics, power, and strength in field sport athletes. Thirty-five men were divided into 4 groups (FST: n = 9; WT: n = 8; PT: n = 9; RST: n = 9) matched for 10-m velocity. Training involved two 60-minute sessions per week for 6 weeks. After the interventions, paired-sample t-tests identified significant (p ≤ 0.05) within-group changes. All the groups increased the 0- to 5-m and 0- to 10-m velocity by 9-10%. The WT and PT groups increased the 5- to 10-m velocity by approximately 10%. All the groups increased step length for all distance intervals. The FST group decreased 0- to 5-m flight time and step frequency in all intervals and increased 0- to 5-m and 0- to 10-m contact time. Power and strength adaptations were protocol specific. The FST group improved horizontal power as measured by a 5-bound test. The FST, PT, and RST groups all improved reactive strength index derived from a 40-cm drop jump, indicating enhanced muscle stretch-shortening capacity during rebound from impacts. The WT group increased absolute and relative strength measured by a 3-repetition maximum squat by approximately 15%. Step length was the major limiting sprint performance factor for the athletes in this study. Correctly administered, each training protocol can be effective in improving acceleration. To increase step length and improve acceleration, field sport athletes should develop specific horizontal and reactive power. PMID:21912294

  6. The effects of different speed training protocols on sprint acceleration kinematics and muscle strength and power in field sport athletes.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Schultz, Adrian B; Knight, Timothy J; Janse de Jonge, Xanne A K

    2012-06-01

    A variety of resistance training interventions are used to improve field sport acceleration (e.g., free sprinting, weights, plyometrics, resisted sprinting). The effects these protocols have on acceleration performance and components of sprint technique have not been clearly defined in the literature. This study assessed 4 common protocols (free sprint training [FST], weight training [WT], plyometric training [PT], and resisted sprint training [RST]) for changes in acceleration kinematics, power, and strength in field sport athletes. Thirty-five men were divided into 4 groups (FST: n = 9; WT: n = 8; PT: n = 9; RST: n = 9) matched for 10-m velocity. Training involved two 60-minute sessions per week for 6 weeks. After the interventions, paired-sample t-tests identified significant (p ≤ 0.05) within-group changes. All the groups increased the 0- to 5-m and 0- to 10-m velocity by 9-10%. The WT and PT groups increased the 5- to 10-m velocity by approximately 10%. All the groups increased step length for all distance intervals. The FST group decreased 0- to 5-m flight time and step frequency in all intervals and increased 0- to 5-m and 0- to 10-m contact time. Power and strength adaptations were protocol specific. The FST group improved horizontal power as measured by a 5-bound test. The FST, PT, and RST groups all improved reactive strength index derived from a 40-cm drop jump, indicating enhanced muscle stretch-shortening capacity during rebound from impacts. The WT group increased absolute and relative strength measured by a 3-repetition maximum squat by approximately 15%. Step length was the major limiting sprint performance factor for the athletes in this study. Correctly administered, each training protocol can be effective in improving acceleration. To increase step length and improve acceleration, field sport athletes should develop specific horizontal and reactive power.

  7. Effects of Combined Foot/Ankle Electromyostimulation and Resistance Training on the In-Shoe Plantar Pressure Patterns during Sprint in Young Athletes

    PubMed Central

    Fourchet, François; Kuitunen, Sami; Girard, Olivier; Beard, Adam J.; Millet, Grégoire P.

    2011-01-01

    Several studies have already reported that specific foot/ankle muscle reinforcement strategies induced strength and joint position sense performance enhancement. Nevertheless the effects of such protocols on sprint performance and plantar loading distribution have not been addressed yet. The objective of the study is to investigate the influence of a 5-wk foot/ankle strength training program on plantar loading characteristics during sprinting in adolescent males. Sixteen adolescent male athletes of a national training academy were randomly assigned to either a combined foot/ankle electromyostimulation and resistance training (FAST) or a control (C) group. FAST consisted of foot medial arch and extrinsic ankle muscles reinforcement exercises, whereas C maintained their usual training routine. Before and after training, in-shoe loading patterns were measured during 30-m running sprints using pressure sensitive insoles (right foot) and divided into nine regions for analysis. Although sprint times remained unchanged in both groups from pre- to post- training (3.90 ± 0.32 vs. 3.98 ± 0.46 s in FAST and 3.83 ± 0.42 vs. 3.81 ± 0.44 s in C), changes in force and pressure appeared from heel to forefoot between FAST and C. In FAST, mean pressure and force increased in the lateral heel area from pre- to post- training (67.1 ± 44.1 vs. 82.9 ± 28.6 kPa [p = 0.06]; 25.5 ± 17.8 vs. 34.1 ± 14.3 N [p = 0.05]) and did not change in the medial forefoot (151.0 ± 23.2 vs. 146.1 ± 30.0 kPa; 142.1 ± 29.4 vs. 136.0 ± 33.8; NS). Mean area increased in FAST under the lateral heel from pre- to post- (4.5 ± 1.3 vs. 5.7 ± 1.6 cm2 [p < 0.05]) and remained unchanged in C (5.5 ± 2.8 vs. 5.0 ± 3.0 cm2). FAST program induced significant promising lateral and unwanted posterior transfer of the plantar loads without affecting significantly sprinting performance. Key points We have evaluated the effects of a foot/ankle strength training program on sprint performance and on related

  8. Coping Styles among Adolescent Competitive Athletes.

    ERIC Educational Resources Information Center

    Anshel, Mark

    1996-01-01

    Examines the various coping strategies that competitive adolescent athletes use to deal with errors, penalties, and unpleasant comments from spectators. Identifies and discusses four coping strategies: avoidance, approach, task-focused, and emotion-focused. Briefly reviews the literature on coping and the results of a survey of Australian…

  9. Sex effect on catecholamine responses to sprint exercise in adolescents and adults.

    PubMed

    Botcazou, Maïtel; Jacob, Christophe; Gratas-Delamarche, Arlette; Vincent, Sophie; Bentué-Ferrer, Danièle; Delamarche, Paul; Zouhal, Hassane

    2007-05-01

    The purpose of this study was to clarify the effect of sex on plasma catecholamine responses to sprint exercise in adolescents and adults. Thirty-six untrained participants took part in this study-9 girls and 10 boys (Tanner Stage 4) and 9 women and 8 men. Each participant performed a 6-s sprint test on a cycle ergometer. Plasma adrenaline (A) and noradrenaline (NA) concentrations were determined successively at rest (A0 and NA0), immediately after the 6-s sprint test (AEX and NAEX), and after 5 min of recovery (A5 and NA5). Peak power, expressed in absolute values or relative to body weight and fat-free mass, was significantly higher in boys than in girls and higher in men than in women (p < .001). No sex effect was observed in AEX in the adolescents, but the NA increase was significantly higher in boys in response to the 6-s sprint (p < .05). In adults, no sex difference was found in NAEX, but AEX was significantly higher in men than in women (p < .05). NAEX was significantly higher in women than in girls (p < .05), and AEX was significantly higher in men than in boys (p < .01). The results of this study suggest that male and female adolescents and young adults might exhibit different catecholamine responses to sprint exercise.

  10. ACVR1B rs2854464 Is Associated with Sprint/Power Athletic Status in a Large Cohort of Europeans but Not Brazilians.

    PubMed

    Voisin, Sarah; Guilherme, João Paulo F L; Yan, Xu; Pushkarev, Vladimir P; Cieszczyk, Pawel; Massidda, Myosotis; Calò, Carla M; Dyatlov, Dmitry A; Kolupaev, Vitaliy A; Pushkareva, Yuliya E; Maciejewska, Agnieszka; Sawczuk, Marek; Lancha, Antonio H; Artioli, Guilherme G; Eynon, Nir

    2016-01-01

    Skeletal muscle strength and mass, major contributors to sprint/power athletic performance, are influenced by genetics. However, to date, only a handful of genetic variants have been associated with sprint/power performance. The ACVR1B A allele (rs rs2854464) has previously been associated with increased muscle-strength in non-athletic cohort. However, no follow-up and/or replications studies have since been conducted. Therefore, the aim of the present study was to compare the genotype distribution of ACVR1B rs2854464 between endurance athletes (E), sprint/power (S/P) athletes, mixed athletes (M), and non-athletic control participants in 1672 athletes (endurance athletes, n = 482; sprint/power athletes, n = 578; mixed athletes, n = 498) and 1089 controls (C) of both European Caucasians (Italian, Polish and Russians) and Brazilians. We have also compared the genotype distribution according to the athlete's level of competition (elite vs. sub-elite). DNA extraction and genotyping were performed using various methods. Fisher's exact test (adjusted for multiple comparisons) was used to test whether the genotype distribution of rs2854464 (AA, AG and GG) differs between groups. The A allele was overrepresented in S/P athletes compared with C in the Caucasian sample (adjusted p = 0.048), whereas there were no differences in genotype distribution between E athletes and C, in neither the Brazilian nor the Caucasian samples (adjusted p > 0.05). When comparing all Caucasian athletes regardless of their sporting discipline to C, we found that the A allele was overrepresented in athletes compared to C (adjusted p = 0.024). This association was even more pronounced when only elite-level athletes were considered (adjusted p = 0.00017). In conclusion, in a relatively large cohort of athletes from Europe and South America we have shown that the ACVR1B rs2854464 A allele is associated with sprint/power performance in Caucasians but not in Brazilian athletes. This reinforces the

  11. 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.

  12. Neuromuscular characteristics and fatigue in endurance and sprint athletes during a new anaerobic power test.

    PubMed

    Paavolainen, L; Häkkinen, K; Nummela, A; Rusko, H

    1994-01-01

    The purpose of this study was to investigate neuromuscular and energy performance characteristics of anaerobic power and capacity and the development of fatigue. Ten endurance and ten sprint athletes performed a new maximal anaerobic running power test (MARP), which consisted of n x 20-s runs on a treadmill with 100-s recovery between the runs. Blood lactate concentration [la-]b was measured after each run to determine submaximal and maximal indices of anaerobic power (P3 mmol.l-1, P5 mmol.l-1, P10 mmol.l-1 and Pmax) which was expressed as the oxygen demand of the runs according to the American College of Sports Medicine equation: the oxygen uptake (ml.kg-1.min-1) = 0.2 x velocity (m.min-1) + 0.9 x slope of treadmill (frac) x velocity (m.min-1) + 3.5. The height of rise of the centre of gravity of the counter movement jumps before (CMJrest) and during (CMJ) the MARP test, as well as the time of force production (tF) and electromyographic (EMG) activity of the leg muscles of CMJ performed after each run were used to describe the neuromuscular performance characteristics. The maximal oxygen uptake (VO2max), anaerobic and aerobic thresholds were determined in the VO2max test, which consisted of n x 3-min runs on the treadmill.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Sprint Performance Changes and Determinants in Afro-Caribbean Adolescents Between 13 and 15 Years Old

    PubMed Central

    Copaver, Karine Babel; Hertogh, Claude; Hue, Olivier

    2012-01-01

    Afro-Caribbean sprinters often reach high performance levels at an early age. Adolescence is a time of morphological and physiological changes. This study was designed to analyze the evolution in parameters of short sprint performance during adolescence in Afro-Caribbean boys, especially the stride number/body height ratio (SN/BH), which is at the interface of technical and morphological factors. Seventy-one 13-year-old boys performed vertical jumps and short sprint races. The races were filmed with a view to determine stride variables. Anthropometric parameters were also measured. The same tests were performed two years later. Body height and SN/BH were the main predictors of sprint performance. The delta of performance was principally explained by stride length and stride number. Although deterioration in technical parameters was expected, the parameters related to body size and stride length were the main sprint performance predictors rather than explosive force. These results could be useful in developing tests to detect sprint potential in youth. PMID:23487285

  14. The Short-Term Effect of Whole Body Vibration Training on Sprint Start Performance in Collegiate Athletes

    PubMed Central

    ROBERTS, BRAD; HUNTER, IAIN; HOPKINS, TY; FELAND, BRENT

    2009-01-01

    Whole body vibration (WBV) is characterized by a vibratory stimulus emitted throughout the body through the use of a vibrating platform on which the subject stands. Studies have shown over 30% increases in maximal explosive strength such as maximal speed biceps curl as well as increases in maximum dynamic force such as maximal sitting bench pull as the result of vibration. The purpose of this study was to investigate the effects of short term whole-body vibration on sprint starts among collegiate track athletes. On the first day eleven subjects were randomly assigned to either a non-vibration or vibration group for initial testing. The vibration group used whole body vibration along with their normal warm-up routine while the non-vibration group did not. Force measurements were taken where the starting blocks were placed using a force plate embedded under the track surface following the warm up. One week later the groups alternated. The results were then compared between vibration and non-vibration groups for individual athletes. The vibration protocol occurred for 60 s at 26 Hz with an amplitude of 4mm on a Galileo 2000 platform. Repeated measures analysis of the variance showed peak resultant force was 6% greater when the vibration platform was utilized prior to the start (p=0.013). Further research is needed to determine whether any meaningful differences exist in sprint start velocity as a result of WBV. There were no observed differences in the 30m sprint times. PMID:27182320

  15. The effect of assisted and resisted sprint training on acceleration and velocity in Division IA female soccer athletes.

    PubMed

    Upton, David E

    2011-10-01

    This investigation evaluated the effects of a 4-week, 12-session training program using resisted sprint training (RST), assisted sprint training (AST), and traditional sprint training (TST) on maximal velocity and acceleration in National Collegiate Athletic Association (NCAA) Division IA female soccer athletes (n = 27). The subjects, using their respective training modality, completed 10 maximal effort sprints of 20 yd (18.3 m) followed by a 20-yd (18.3 m) deceleration to jog. Repeated measures multivariate analyses of variance and analyses of variance demonstrated significant (p < 0.001) 3-way interactions (time × distance × group) and 2-way interactions (time × group), respectively, for both velocity and acceleration. Paired t-tests demonstrated that maximum 40-yd (36.6-m) velocity increased significantly in both the AST (p < 0.001) and RST (p < 0.05) groups, with no change in the TST group. Five-yard (4.6-m), 15-yd (13.7 m), 5- to 15-yd (4.6- to 13.7-m) acceleration increased significantly (p < 0.01) in the AST group and did not change in the RST and TST groups. Fifteen- to 25-yd (13.7- to 22.9-m) acceleration increased significantly (p < 0.01) in the RST group, decreased significantly (p < 0.01) in the AST group, and was unchanged in the TST group. Twenty-five to 40-yd (22.9- to 36.6-m) acceleration increased significantly (p < 0.05) in the RST group and remained unchanged in the AST and TST groups. It is purposed that the increased 5-yd (4.6-m) and 15-yd (13.7-m) accelerations were the result of enhanced neuromuscular facilitation in response to the 12-session supramaximal training protocol. Accordingly, it is suggested that athletes participating in short distance acceleration events (i.e., ≤15 yd; ≤13.7 m) use AST protocols, whereas athletes participating in events that require greater maximum velocity (i.e., >15 yd; > 13.7 m) should use resisted sprint training protocols.

  16. ACVR1B rs2854464 Is Associated with Sprint/Power Athletic Status in a Large Cohort of Europeans but Not Brazilians

    PubMed Central

    Voisin, Sarah; Guilherme, João Paulo F. L.; Yan, Xu; Pushkarev, Vladimir P.; Cieszczyk, Pawel; Massidda, Myosotis; Calò, Carla M.; Dyatlov, Dmitry A.; Kolupaev, Vitaliy A.; Pushkareva, Yuliya E.; Maciejewska, Agnieszka; Sawczuk, Marek; Lancha, Antonio H.; Artioli, Guilherme G.

    2016-01-01

    Skeletal muscle strength and mass, major contributors to sprint/power athletic performance, are influenced by genetics. However, to date, only a handful of genetic variants have been associated with sprint/power performance. The ACVR1B A allele (rs rs2854464) has previously been associated with increased muscle-strength in non-athletic cohort. However, no follow-up and/or replications studies have since been conducted. Therefore, the aim of the present study was to compare the genotype distribution of ACVR1B rs2854464 between endurance athletes (E), sprint/power (S/P) athletes, mixed athletes (M), and non-athletic control participants in 1672 athletes (endurance athletes, n = 482; sprint/power athletes, n = 578; mixed athletes, n = 498) and 1089 controls (C) of both European Caucasians (Italian, Polish and Russians) and Brazilians. We have also compared the genotype distribution according to the athlete’s level of competition (elite vs. sub-elite). DNA extraction and genotyping were performed using various methods. Fisher's exact test (adjusted for multiple comparisons) was used to test whether the genotype distribution of rs2854464 (AA, AG and GG) differs between groups. The A allele was overrepresented in S/P athletes compared with C in the Caucasian sample (adjusted p = 0.048), whereas there were no differences in genotype distribution between E athletes and C, in neither the Brazilian nor the Caucasian samples (adjusted p > 0.05). When comparing all Caucasian athletes regardless of their sporting discipline to C, we found that the A allele was overrepresented in athletes compared to C (adjusted p = 0.024). This association was even more pronounced when only elite-level athletes were considered (adjusted p = 0.00017). In conclusion, in a relatively large cohort of athletes from Europe and South America we have shown that the ACVR1B rs2854464 A allele is associated with sprint/power performance in Caucasians but not in Brazilian athletes. This reinforces the

  17. Athletic Involvement and Adolescent Delinquency

    ERIC Educational Resources Information Center

    Miller, Kathleen E.; Melnick, Merrill J.; Barnes, Grace M.; Sabo, Don; Farrell, Michael P.

    2007-01-01

    Although conventional wisdom suggests that organized sport deters delinquency by building character, structuring adolescents' time, and providing incentives for socially approved behavior, the empirical evidence to date has been mixed. Based on a sample of approximately 600 Western New York adolescents, the present study examined how self-reported…

  18. Arthroscopic Treatment of FAI in Adolescent Athletes

    PubMed Central

    Byrd, J. W. Thomas; Jones, Kay S.

    2015-01-01

    Objectives: Athletic activities are implicated in the development of symptomatic FAI in adolescents as reflected by a high prevalence of sports participation among young individuals who present with this problem. The purpose of this study is to report the outcomes of arthroscopic treatment. Methods: All patients undergoing arthroscopy are prospectively assessed with a modified Harris hip score. 104 athletes (117 hips) were identified among 108 consecutive adolescents (122 hips) less than 18 years of age who had undergone arthroscopic surgery for FAI and had achieved minimum one-year follow-up. This cohort of athletes represents the substance of this report. Results: Follow-up averaged 28 months (range 12-60 months). Average age was 16 years (range 12-17 years). There were 47 males and 57 females. The average improvement was 22 points (preop 73; postop 95) with 113 hips (97 %) improved with 112 (96%) good & excellent results. Eighty-eight athletes (84%) returned to their sport. Among the 16 that did not return to sports, 5 were unable, 6 chose not, and 5 had completed their high school athletic careers. Most common sports were football 15, soccer 13, basketball 13, dance 11, volleyball 7, cross-country 7, swim 7, gymnastics 5, baseball 4, softball 4, and lacrosse 4. FAI correction was performed for 33 cam, 17 pincer, and 67 combined lesions. 107 labral tears underwent 82 refixations and 24 debridements. There were 99 acetabular chondral lesions (42 Grade I, 18 Grade II, 34 Grade III, 5 Grade IV) with four microfractures. There were 3 femoral chondral lesions (1 Grade II, 2 Grade III). Seven loose bodies were removed and 19 lesions of the ligamentum teres were debrided. Concomitant extra-articular procedures included 13 iliopsoas tendon releases, two iliotibial band tendoplasties, and one trochanteric bursectomy. There were two complications, transient pudendal neurapraxias, that resolved within two weeks. Four patients underwent repeat arthroscopy and one a PAO

  19. A group-enhanced sprint interval training program for amateur athletes.

    PubMed

    Martin, Luc J; Anderson, Scott H; Schmale, Matthew S; Hallworth, Jillian R; Hazell, Tom J

    2016-08-01

    Sprint interval training (SIT) can elicit improvements in aerobic and anaerobic capacity. While variations in SIT protocols have been investigated, the influence of social processes cannot be overlooked. As research supports the use of groups to influence individual cognitions and behaviours, the current project assessed the effectiveness of a group-based intervention with participants conducting SIT. Specifically, 53 amateur athletes (age, 21.9 ± 2.9 years; 53% females) took part in a 4-week training program (3 sessions per week, 30-s "all-out" efforts with 4 min active recovery, repeated 4-6 times per session), and were assigned to "true group", aggregate, or individual conditions. Results indicated no significant differences between groups for the physiological measures. With regards to training improvements from baseline for all participants- regardless of condition - significant main effects for time were identified for maximal oxygen uptake (2.5-2.8 mL·kg(-1)·min(-1), p < 0.001, η(2) = 0.03), time-trial performance (14-32 s, p < 0.001, η(2) = 0.37), and anaerobic power (1.1-1.7 k·h(-1), p < 0.001, η(2) = 0.66). With regards to the psychological measures, significant main effects between groups were found for motivation (p = 0.033, η(2) = 0.13), task self-efficacy (p = 0.018, η(2) = 0.15), and scheduling self-efficacy (p = 0.003, η(2) = 0.22). The true group experienced greater improvements in motivation than the individual condition, but the aggregate and individual conditions demonstrated greater increases in task and scheduling self-efficacy. Though the SIT paradigm employed induced training improvements similar to previous work, the group intervention was not able to further these improvements. PMID:27377136

  20. Adolescent idiopathic scoliosis in athletes: is there a connection?

    PubMed

    Kenanidis, Eustathios I; Potoupnis, Michael E; Papavasiliou, Kyriakos A; Sayegh, Fares E; Kapetanos, George A

    2010-06-01

    The potential relationship between adolescent idiopathic scoliosis (AIS) and sports is rather vague. Sports have often been considered to be a causative factor of, or a treatment option for the former, particularly among adolescent athletes who are engaged in certain athletic activities. The highly repetitive nature of sports, amenorrhea, exercise-related exerted stress on the immature spine of professional adolescent athletes, and the joint laxity that may coexist during adolescence, have also been associated with an increased incidence of AIS. The purpose of this article is to discuss the potential connection between sports and AIS by reviewing the existing literature. PMID:20631476

  1. Effect of repeated sprints on postprandial endothelial function and triacylglycerol concentrations in adolescent boys.

    PubMed

    Sedgwick, Matthew J; Morris, John G; Nevill, Mary E; Barrett, Laura A

    2015-01-01

    This study investigated whether repeated, very short duration sprints influenced endothelial function (indicated by flow-mediated dilation) and triacylglycerol concentrations following the ingestion of high-fat meals in adolescent boys. Nine adolescent boys completed two, 2-day main trials (control and exercise), in a counter-balanced, cross-over design. Participants were inactive on day 1 of the control trial but completed 40 × 6 s maximal cycle sprints on day 1 of the exercise trial. On day 2, capillary blood samples were collected and flow-mediated dilation measured prior to, and following, ingestion of a high-fat breakfast and lunch. Fasting flow-mediated dilation and plasma triacylglycerol concentration were similar in the control and exercise trial (P > 0.05). In the control trial, flow-mediated dilation was reduced by 20% and 27% following the high-fat breakfast and lunch; following exercise these reductions were negated (main effect trial, P < 0.05; interaction effect trial × time, P < 0.05). The total area under the plasma triacylglycerol concentration versus time curve was 13% lower on day 2 in the exercise trial compared to the control trial (8.65 (0.97) vs. 9.92 (1.16) mmol · l(-1) · 6.5 h, P < 0.05). These results demonstrate that repeated 6 s maximal cycle sprints can have beneficial effects on postprandial endothelial function and triacylglycerol concentrations in adolescent boys.

  2. Assessment and treatment of hip pain in the adolescent athlete.

    PubMed

    Giordano, Brian D

    2014-12-01

    Hip pain in the adolescent athlete is a common source of functional impairment and can limit athletic performance. In the past, many intra- and extra-articular hip abnormalities went unrecognized and were left untreated because of insufficient diagnostic imaging and limited surgical options. However, over the past 20 years, there has been a tremendous expansion research, and the understanding of the etiology of hip pain among such athletes has grown. Improvements in imaging modalities and technical innovations have led to greater diagnostic insights and creative new treatment strategies. This article explores the etiology and treatment of hip pain in the adolescent athlete. PMID:25439016

  3. Rotator cuff injuries in adolescent athletes.

    PubMed

    Weiss, Jennifer M; Arkader, Alexandre; Wells, Lawrence M; Ganley, Theodore J

    2013-03-01

    The cause of rotator cuff injuries in the young athlete has been described as an overuse injury related to internal impingement. Abduction coupled with external rotation is believed to impinge on the rotator cuff, specifically the supraspinatus, and lead to undersurface tears that can progress to full-thickness tears. This impingement is believed to be worsened with increased range of motion and instability in overhead athletes. A retrospective review of seven patients diagnosed with rotator cuff injuries was performed to better understand this shoulder injury pattern. The type of sport played, a history of trauma, diagnosis, treatment method, and outcome were noted. Six patients were male and one was a female. Baseball was the primary sport for four patients, basketball for one, gymnastics for one, and wrestling for one. The following injury patterns were observed: two patients tore their subscapularis tendon, two sustained avulsion fractures of their lesser tuberosity, one tore his rotator interval, one tore his supraspinatus, and one avulsed his greater tuberosity. Only four patients recalled a specific traumatic event. Three patients were treated with arthroscopic rotator cuff repair, three with miniopen repair, and one was treated with rehabilitation. Six of the seven patients returned to their preinjury level of sport after treatment. Rotator cuff tears are rare in the adolescent age group. The injury patterns suggest that acute trauma likely accounts for many rotator cuff tears and their equivalents in the young patient. Adolescents with rotator cuff tears reliably return to sports after treatment. The possibility of rotator cuff tears in skeletally immature athletes should be considered. The prognosis is very good once this injury is identified and treated. PMID:22668571

  4. Rotator cuff injuries in adolescent athletes.

    PubMed

    Weiss, Jennifer M; Arkader, Alexandre; Wells, Lawrence M; Ganley, Theodore J

    2013-03-01

    The cause of rotator cuff injuries in the young athlete has been described as an overuse injury related to internal impingement. Abduction coupled with external rotation is believed to impinge on the rotator cuff, specifically the supraspinatus, and lead to undersurface tears that can progress to full-thickness tears. This impingement is believed to be worsened with increased range of motion and instability in overhead athletes. A retrospective review of seven patients diagnosed with rotator cuff injuries was performed to better understand this shoulder injury pattern. The type of sport played, a history of trauma, diagnosis, treatment method, and outcome were noted. Six patients were male and one was a female. Baseball was the primary sport for four patients, basketball for one, gymnastics for one, and wrestling for one. The following injury patterns were observed: two patients tore their subscapularis tendon, two sustained avulsion fractures of their lesser tuberosity, one tore his rotator interval, one tore his supraspinatus, and one avulsed his greater tuberosity. Only four patients recalled a specific traumatic event. Three patients were treated with arthroscopic rotator cuff repair, three with miniopen repair, and one was treated with rehabilitation. Six of the seven patients returned to their preinjury level of sport after treatment. Rotator cuff tears are rare in the adolescent age group. The injury patterns suggest that acute trauma likely accounts for many rotator cuff tears and their equivalents in the young patient. Adolescents with rotator cuff tears reliably return to sports after treatment. The possibility of rotator cuff tears in skeletally immature athletes should be considered. The prognosis is very good once this injury is identified and treated.

  5. 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.

  6. The effect of warm-ups incorporating different volumes of dynamic stretching on 10- and 20-m sprint performance in highly trained male athletes.

    PubMed

    Turki, Olfa; Chaouachi, Anis; Behm, David G; Chtara, Hichem; Chtara, Moktar; Bishop, David; Chamari, Karim; Amri, Mohamed

    2012-01-01

    Recently, athletes have transitioned from traditional static stretching during warm-ups to incorporating dynamic stretching routines. However, the optimal volume of dynamic drills is yet to be identified. The aim of this repeated-measures study was to examine varying volumes (1, 2, and 3 sets) of active dynamic stretching (ADS) in a warm-up on 10- and 20-m sprint performance. With a within-subject design, 16 highly trained male participants (age: 20.9 ± 1.3 years; height: 179.7 ± 5.7 cm; body mass: 72.7 ± 7.9 kg; % body fat: 10.9 ± 2.4) completed a 5-minute general running warm-up before performing 3 preintervention measures of 10- to 20-m sprint. The interventions included 1, 2, and 3 sets of active dynamic stretches of the lower-body musculature (gastrocnemius, gluteals, hamstrings, quadriceps, and hip flexors) performed approximately 14 times for each exercise while walking (ADS1, ADS2, and ADS3). The active dynamic warm-ups were randomly allocated before performing a sprint-specific warm-up. Five minutes separated the end of the warm-up and the 3 postintervention measures of 10- to 20-m sprints. There were no significant time, condition, and interaction effects over the 10-m sprint time. For the 0- to 20-m sprint time, a significant main effect for the pre-post measurement (F = 10.81; p < 0.002), the dynamic stretching condition (F = 6.23; p = 0.004) and an interaction effect (F = 41.19; p = 0.0001) were observed. A significant decrease in sprint time (improvement in sprint performance) post-ADS1 (2.56%, p = 0.001) and post-ADS2 (2.61%, p = 0.001) was observed. Conversely, the results indicated a significant increase in sprint time (sprint performance impairment) post-ADS3 condition (2.58%, p = 0.001). Data indicate that performing 1-2 sets of 20 m of active dynamic stretches in a warm-up can enhance 20-m sprint performance. The results delineated that 3 sets of ADS repetitions could induce acute fatigue and impair sprint performance within 5 minutes of the

  7. Bone Health in Adolescent Athletes with a Focus on Female Athlete Triad

    PubMed Central

    Ackerman, Kathryn E.; Misra, Madhusmita

    2013-01-01

    Peak bone mass (PBM) is a negative predictor of osteoporosis and life-long fracture risk. Because osteoporosis is such a prevalent disease with life-threatening consequences later in life, it is important to try to maximize PBM. Adolescence is a critical time for bone acquisition. This review discusses some of the differences in male and female skeletal development and modifiable factors that enhance bone accrual in this age group, particularly in athletes. Hormonal influences, physical activity effects, and nutritional contributions are presented, with a focus on the adolescent athlete. Emphasis is placed on the importance of appropriate energy availability in this age group. The Female Athlete Triad (the inter-relationship of decreased energy availability, menstrual irregularity, and low bone density) is an important issue for adolescent, athletic women, and is therefore reviewed, including prevention and treatment strategies. Recommendations for maximizing bone density in both male and female adolescents are discussed. PMID:21378496

  8. Coping with sports injuries: an examination of the adolescent athlete.

    PubMed

    Manuel, Janeen C; Shilt, Jeffrey S; Curl, Walton W; Smith, Jeffrey A; Durant, Robert H; Lester, Laura; Sinal, Sara H

    2002-11-01

    Forty-eight injured adolescent athletes completed questionnaires over 3 months after injury to assess psychosocial outcomes. Depressive symptoms decreased over time, and the lack of positive stress and high athletic identity were associated with early depressive symptoms after accounting for injury severity. Increased social support was associated with lower initial depressive symptoms.

  9. Coaching Strategies for Helping Adolescent Athletes Cope with Stress

    ERIC Educational Resources Information Center

    Gilbert, Jenelle N.; Gilbert, Wade; Morawski, Cynthia

    2007-01-01

    This article discusses the various sources of athlete stress and the strategies that coaches can use to help young athletes cope with it. The information is based on a study with a competitive adolescent soccer team and its two coaches, and a review of the coaching and sport psychology literature. The suggested coaching strategies can help to…

  10. Relationships between anthropometric measures and athletic performance, with special reference to repeated-sprint ability, in the Qatar national soccer team.

    PubMed

    Brocherie, Franck; Girard, Olivier; Forchino, Fabricio; Al Haddad, Hani; Dos Santos, Gilvan A; Millet, Grégoire P

    2014-01-01

    The aim of this study was to determine potential relationships between anthropometric parameters and athletic performance with special consideration to repeated-sprint ability (RSA). Sixteen players of the senior male Qatar national soccer team performed a series of anthropometric and physical tests including countermovement jumps without (CMJ) and with free arms (CMJwA), straight-line 20 m sprint, RSA (6 × 35 m with 10 s recovery) and incremental field test. Significant (P < 0.05) relationships occurred between muscle-to-bone ratio and both CMJs height (r ranging from 0.56 to 0.69) as well as with all RSA-related variables (r < -0.53 for sprinting times and r = 0.54 for maximal sprinting speed) with the exception of the sprint decrement score (Sdec). The sum of six skinfolds and adipose mass index were largely correlated with Sdec (r = 0.68, P < 0.01 and r = 0.55, P < 0.05, respectively) but not with total time (TT, r = 0.44 and 0.33, P > 0.05, respectively) or any standard athletic tests. Multiple regression analyses indicated that muscular cross-sectional area for mid-thigh, adipose index, straight-line 20 m time, maximal sprinting speed and CMJwA are the strongest predictors of Sdec (r(2) = 0.89) and TT (r(2) = 0.95) during our RSA test. In the Qatar national soccer team, players' power-related qualities and RSA are associated with a high muscular profile and a low adiposity. This supports the relevance of explosive power for the soccer players and the larger importance of neuromuscular qualities determining the RSA. PMID:24742185

  11. Changes in lung function during adolescence in athletes and non-athletes.

    PubMed

    Lakhera, S C; Kain, T C; Bandopadhyay, P

    1994-09-01

    The purpose of this study was to evaluate the lung function in Indian athletes and non-athletes during adolescence. For this, lung functions in 40 boys (twenty athletes and twenty non-athletes) in the age range of 13 to 16 years, were evaluated over a period of two years at yearly intervals. The variables studied were Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), Expiratory Reserve Volume (ERV), Inspiratory Capacity (IC) and Maximum Voluntary Ventilation (MVV). Our results suggest that the development of the lung during adolescence under proper nutritional and health conditions is governed by the process of growth with no or negligible additional effects of physical activity. It is summarized that physical activity during growth may increase endurance in respiratory muscles. However, the findings of this study does not reject the possibility that lung size may increase by a strenuous and prolonged strength training regimen during adolescence.

  12. Effect of sprint interval exercise on postexercise metabolism and blood pressure in adolescents.

    PubMed

    Burns, Stephen F; Oo, Hnin Hnin; Tran, Anh Thanh Thuy

    2012-02-01

    The current study examined the effect of sprint interval exercise on postexercise oxygen consumption, respiratory-exchange ratio (RER), substrate oxidation, and blood pressure in adolescents. Participants were 10 normal-weight healthy youth (7 female), age 15-18 years. After overnight fasts, each participant undertook 2 trials in a random balanced order: (a) two 30-s bouts of sprint interval exercise on a cycle ergometer and (b) rested in the laboratory for an equivalent period. Time-matched measurements of oxygen consumption, RER, and blood pressure were made 90 min into recovery, and substrate oxidation were calculated over the time period. Total postexercise oxygen uptake was significantly higher in the exercise than control trial over the 90 min (mean [SD]: control 20.0 [6.0] L, exercise 24.8 [9.8] L; p=.030). After exercise, RER was elevated above control but then fell rapidly and was lower than control 30-60 min postexercise, and fat oxidation was significantly higher in the exercise than control trial 45-60 min postexercise. However, total fat oxidation did not differ between trials (control 4.5 [2.5] g, exercise 5.4 [2.7] g; p=.247). Post hoc tests revealed that systolic blood pressure was significantly lower than in control at 90 min postexercise (control 104 [10] mm Hg, exercise 99 [10] mm Hg; p<.05). These data indicate that acute sprint interval exercise leads to short-term increases in oxygen uptake and reduced blood pressure in youth. The authors suggest that health outcomes in response to sprint interval training be examined in children.

  13. Repeated sprint training improves intermittent peak running speed in team-sport athletes.

    PubMed

    Hunter, Jayden R; O'Brien, Brendan J; Mooney, Mitchell G; Berry, Jason; Young, Warren B; Down, Neville

    2011-05-01

    The aim of this study was to compare the effect of 2 repeated sprint training interventions on an intermittent peak running speed (IPRS) test designed for Australian Rules football. The test required participants to perform 10 × 10-m maximal efforts on an 80-m course every 25 seconds, for each of which the mean peak speed (kilometers per hour) was recorded to determine IPRS. The training interventions were performed twice weekly for 4 weeks immediately before regular football training. In the constant volume intervention (CVol), sprint repetition number remained at 10 (n = 9), and in the linear increase in volume (LIVol) intervention, repetition number increased linearly each week by 2 repetitions (n = 12). Intermittent peak running speed, 300-m shuttle test performance, and peak running speed were assessed before and upon completion of training. All measures were compared to a control group (CON; n = 8) in which players completed regular football training exclusively. Intermittent peak running speed performance in CVol and LIVol improved significantly (p < 0.01) by 5.2 and 3.8%, respectively, with no change in IPRS for CON. There were no differences in IPRS changes between CVol and LIVol. Additionally, peak running speed improved significantly (p < 0.01) by 5.1% for CVol, whereas 300-m shuttle performance improved significantly (p < 0.01) by 2.6% for LIVol only. Intermittent peak running speed, 300-m shuttle performance and peak running speed were improved after 4 weeks of training; however, progressively increasing sprint repetition number had no greater advantage on IPRS adaptation. Additionally, exclusive regular football training over a 4-week period is unlikely to improve IPRS, peak running speed, or 300-m shuttle performance.

  14. Performance parameters in children and adolescent athletes.

    PubMed

    Birrer, R B; Levine, R

    1987-01-01

    Success in sports, as measured by competitive performance, is dependent upon a number of significant mental and physical components. Somatotype, motor skills, age, nutritional status, physiology, psychology, training level, genetic endowment, and injury risk are the major independent variables influencing performance. Unfortunately, the data available in this area of sports medicine are not always reliable or allow interstudy comparisons. This article reviews the historical and current information used to predict human performance in sports at the childhood and adolescent level. Although mesomorphy, and to a lesser extent ectomorphy, are positively associated with enhanced performance, successful athletes tend to have or acquire somatotypes characteristic of individuals already successful in a particular sport. For the most part, motor skills are age (chronological) and gender dependent. In general, the efficiency of movement progressively improves throughout childhood and into early adolescence and is highly dependent on environmental influences. A lower anaerobic and aerobic capacity reduces performance in the child and adolescent. Nonetheless, regular training can favourably improve motor skills and physiological fitness parameters. The relationship between endurance performance and aerobic capacity, however, is not strong at any age during childhood. Performance levels are reduced if nutrition is inadequate. A number of mental factors such as aggression, spirit, and self-confidence are also related to sports performance, although their correlation is unclear at present. Performance is influenced by the effect of genetic factors on specific traits in 30 to 85% of cases. Risk factors that negatively impact on performance levels include a history of previous injury, excessive training schedules, decreased fitness endurance, joint looseness or tightness, and certain personality traits. It is suggested that sport performance may be optimised by the early

  15. The adolescent female athlete: current concepts and conundrums.

    PubMed

    Greydanus, Donald E; Omar, Hatim; Pratt, Helen D

    2010-06-01

    The adolescent female athlete has become a common part of the sports environment at all levels from childhood play to professional adult sports. This article considers various issues common to this athlete to help clinicians care for their patients. Basic sports physiology is reviewed and then specific conditions are considered, including iron deficiency anemia, stress urinary incontinence, breast issues (ie, pain, asymmetry, galactorrhea, injury), the female athlete triad (ie, menstrual dysfunction, abnormal eating patterns, and osteopenia or osteoporosis), and injuries. Clinical conundrums are considered including the difficulty in caring for a dedicated athlete whose intense love of her sport may lead to menstrual and bone loss complications. The knowledgeable clinician in the twenty-first century can be of considerable help to the female athlete who is at and beyond puberty. PMID:20538152

  16. Cervical spine injuries in the pediatric and adolescent athlete.

    PubMed

    Herman, Martin J

    2006-01-01

    Injuries of the cervical spine in the pediatric and adolescent athlete are less common than other musculoskeletal injuries. Although many of these injuries are relatively minor, serious and potentially unstable or progressive spinal injury must be excluded. Important anatomic differences between the child younger than 10 years and older children and adolescents influence the types of injuries sustained and make assessment of the child's cervical spine sometimes difficult for practitioners accustomed to treating adolescent and adult athletes. Stable soft-tissue injuries of the cervical spine are the most common injuries that occur in all athletes. These injuries are responsive to symptomatic treatment and aggressive rehabilitation. Stingers are injuries of the brachial plexus and upper cervical roots that result from stretching or compressive forces associated with collision sports. Rapid return of sensory and motor dysfunction of a single upper extremity characterizes this entity; long-term disability is rare. Cervical cord neurapraxia (CCN) with transient quadriplegia is most commonly seen in football players. Most athletes fully recover. Cervical canal stenosis as defined by a Pavlov/Torg ratio of less than or equal to 0.8 is predictive of recurrent CCN. Young athletes sustain CCN secondary to hypermobility of the immature cervical spine. Return to play after these injuries is controversial. The athlete with Down syndrome and potential cervical hypermobility requires a careful cervical and neurologic evaluation prior to clearance for participation in sports. PMID:16958497

  17. Medial malleolar stress fracture in an adolescent athlete.

    PubMed

    Menge, Travis J; Looney, Colin G

    2015-01-01

    A stress fracture of the medial malleolus in adolescent athletes is a rare condition with poorly defined outcomes. Proper management requires early recognition, with treatment directed toward the athlete's safe return to their sport. Failure to assess and manage the fracture properly can result in significant complications, including fracture progression, delayed healing, nonunion, and chronic pain. We present the case of a medial malleolar stress fracture in a 14-year-old football player, who was successfully able to return to competition 4 weeks after surgical treatment. We have also provided a review of the published data regarding the management of these injuries and recommendations for returning athletes to competition.

  18. 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

  19. After-school fitness performance is not altered after physical education lessons in adolescent athletes.

    PubMed

    Faigenbaum, Avery D; McFarland, James E; Buchanan, Erin; Ratamess, Nicholas A; Kang, Jie; Hoffman, Jay R

    2010-03-01

    Physical education (PE) provides a unique opportunity for school-age youth to establish health habits, although some young athletes are exempt from PE and others do not participate because of a concern regarding the lingering effects of fatigue on after-school fitness performance. The purpose of this study was to examine the acute effects of different PE lessons on after-school fitness performance in young athletes. Twenty athletes (14-18 years) participated in 3 different PE lessons that consisted of aerobic exercise (AE), resistance training (RT), or basketball skill training (BS). Fitness performance was assessed after-school following each lesson and after a control day without PE. There were no significant differences in flexibility (34.1 +/- 6.5, 34.7 +/- 1.3, 33.5 +/- 7.2, and 33.6 +/- 7.3 cm), vertical jump (46.3 +/- 14.7, 46.2 +/- 13.6, 46.4 +/- 13.4, and 45.6 +/- 14.2 cm), long jump (175.0 +/- 36.4, 174.2 +/- 36.3, 172.7 +/- 35.8, and 171.9 +/- 34.7 cm), medicine ball toss (348.9 +/- 121.8, 342.0 +/- 120.6, 353.9 +/- 123.6, and 348.4 +/- 129.1 cm), proagility shuttle run (5.8 +/- 0.5, 5.7 +/-0.53, 5.8 +/- 0.52, and 5.8 +/- 0.5 seconds), 20-m sprint (3.7 +/- 0.4, 3.7 +/- 0.4, 3.7 +/- 0.3, and 3.7 +/- 0.3 seconds), and 200-m sprint (36.3 +/- 4.7, 35.1 +/- 4.0, 35.9 +/- 5.9, and 35.4 +/- 5.4 seconds) after AE, RT, BS, or the control day, respectively. These findings suggest that an exercise lesson or skill-based PE class will not have an adverse effect on after-school fitness performance in adolescent athletes.

  20. Self-Esteem of Adolescent Athletes.

    ERIC Educational Resources Information Center

    Lee, Annette L.

    While self-esteem develops after life's primary needs have been satisfied, other factors can influence its development. This thesis investigates the self-esteem of high school and college athletes. The independent variables investigated were gender, athletic participation, family structure, and reported grades. The dependent variables were the…

  1. Gratitude and Adolescent Athletes' Well-Being

    ERIC Educational Resources Information Center

    Chen, Lung Hung; Kee, Ying Hwa

    2008-01-01

    Two cross-sectional studies were conducted to examine the relationships between gratitude and athletes' well-being. Study 1 examines the relationship between dispositional gratitude and well-being, while Study 2 investigates the relationship between sport-domain gratitude and well-being. In Study 1, 169 Taiwanese senior high school athletes (M =…

  2. Creatine and the Male Adolescent Athlete

    ERIC Educational Resources Information Center

    Schumaker, Shauna; Eyers, Christina; Cappaert, Thomas

    2012-01-01

    As the level of competition in youth sports increases, so does athletes' vulnerability to experimenting with performance-enhancing aids (PEAs) at alarmingly young ages. One of the more commonly used PEAs is a supplement called creatine, which has the ability to generate muscular energy, allowing athletes to train at higher intensities for longer…

  3. Adolescent aesthetic athletes: a group at risk for eating pathology?

    PubMed

    Van Durme, Kim; Goossens, Lien; Braet, Caroline

    2012-04-01

    Previous research shows that leanness- and weight-dependent sports increase the risk of developing disturbed eating behaviour. This study investigated whether adolescent aesthetic athletes (n=68, M=14.6 years), particularly ballet dancers and figure skaters, exhibit more eating pathology compared to the general population. Furthermore, it was investigated whether sport-related factors have explanatory value for the dieting behaviour of aesthetic athletes. To asses eating pathology, reliable and valid self-report questionnaires were used including the Eating Disorder Inventory-II, the Children's Eating Disorder Examination-Questionnaire and the Dutch Eating Behaviour Questionnaire. Results show that female aesthetic athletes show more drive for thinness, features of bulimia, dieting behaviour and concerns about weight and shape compared to female adolescents from the general population. Concerning the explanation of dieting behaviour in aesthetic athletes, both sport-related factors (competition state anxiety) and general risk factors (eating concern) seem to be relevant. These results suggest that female aesthetic athletes show more disturbed eating behaviour and thoughts than female adolescents from the general population and therefore may have an enhanced risk of developing clinical eating disorders.

  4. The validity and reliability of a global positioning satellite system device to assess speed and repeated sprint ability (RSA) in athletes.

    PubMed

    Barbero-Alvarez, José C; Coutts, Aaron; Granda, Juan; Barbero-Alvarez, Verónica; Castagna, Carlo

    2010-03-01

    There is a limited understanding of the validity and reliability of commercially available global positioning satellite (GPS) devices for assessing repeated sprint performance in athletes. The aims of this study were to assess the convergent validity and the test-retest reliability of a GPS device for measuring repeated sprint ability test (RSAT) variables. Two groups participated in this study, a group of 21 physical education students (age: 20.2+/-2.3 years, stature: 1.75+/-0.42 m, body mass: 68.0+/-6.8kg) and a second group 14 elite junior soccer players (age: 14.5+/-1.2 years, stature: 1.60+/-0.09 m, body mass: 57.7+/-3.8kg) volunteered to participate in this study. Convergent validity was assessed as the correlation between sprint performance (15 and 30-m) using both timing lights and a portable GPS device during a RSAT (7 x 30-m sprints with 30-s of active recovery). The 7 x 30-m RSAT test-retest reliability using GPS device was assessed in elite junior soccer players repeating the test 1 week apart and expressing reliability as a coefficient of variation. Results showed a strong correlation between peak speed measures with the GPS device and RSAT performance measured with timing lights for the 15-m (r(2)=0.87, p<0.001, N=147) and 30-m (r(2)=0.94, p<0.001, N=147) splits, respectively. There was a low coefficient of variation for summated maximal speed (1.7%) and peak speed (1.2%) during the 7 x 30-m RSAT, but high variation for the percentage decrement score (36.2%). These results provide evidence to support the use of the GPS device as an alternative measure to assess repeated sprint performance but suggest a percentage decrement score is not a reliable measure of RSAT performance.

  5. Common medial elbow injuries in the adolescent athlete.

    PubMed

    Leahy, Ian; Schorpion, Melissa; Ganley, Theodore

    2015-01-01

    Recently there has been increased year-round sports participation among children and adolescents with limited to no rest periods. This has led to increases in pediatric repetitive stress injuries, once considered a rarity. Whether in the throwing athlete or in the athlete that experiences repetitive axial loading; increased medial tension and overload syndromes can lead to stress reactions and fractures. This occurs in the developing athlete due to the bone being weaker than the surrounding tendons and ligaments. The medial elbow is a high stress area and is susceptible to many conditions including apophysitis , avulsion fractures and ulnar collateral ligament disruption. Valgus stress can cause injury to the medial elbow which can lead to increased lateral compression, Panner's disease and osteochondral lesions of the capitellum and olecranon. The purpose of this manuscript is to review common elbow disorders in the adolescent population, outline management and highlight important features of rehabilitation. PMID:25840494

  6. Contribution of Athletic Identity to Child and Adolescent Physical Activity

    PubMed Central

    Anderson, Cheryl B.; Mâsse, Louise C.; Zhang, Hong; Coleman, Karen J.; Chang, Shine

    2009-01-01

    Background Identity theorists maintain that domain-specific self-concepts help explain the differential investment of people’s time and effort in various activities. Purpose This study examined the contribution of athletic identity and three key demographic variables to physical activity and sports team participation. Methods Students in Grades 4–5 (n=391, mean age 9.9 years, range 8–13 years, collected in 2003) and Grades 7–8 (n=948, mean age 13.6 years, range 11–15 years, collected in 2002 and 2006) completed the 40-item Athletic Identity Questionnaire, which measures self-perceptions of athletic appearance; competence; importance of physical activity and sports; and encouragement for activity from parents, teachers, and friends. Hierarchic multiple regression analyses in 2008 assessed the effects of athletic identity, race/ethnicity group, gender, and overweight status on 7-day moderate-to-vigorous physical activity (MVPA) and organized sport team participation in each age group. Results In children and adolescents, the global score of athletic identity was independently, positively related to MVPA (p<0.0001, p<0.0001, respectively) and team participation (p<0.0001, p<0.0001, respectively), after controlling for demographic variables. More variance in MVPA was explained in children (23%) than in adolescents (5%), in contrast to team sports (5% in children, 15% in adolescents). In the subscale analyses, positive relationships for appearance, competence, importance, and parental encouragement persisted independent of demographic factors. Conclusions Results support the role of athletic self-concept in promoting physical activity and organized sport participation in children and adolescents. PMID:19595559

  7. Triceps surae muscle-tendon properties in older endurance- and sprint-trained athletes.

    PubMed

    Stenroth, Lauri; Cronin, Neil J; Peltonen, Jussi; Korhonen, Marko T; Sipilä, Sarianna; Finni, Taija

    2016-01-01

    Previous studies have shown that aging is associated with alterations in muscle architecture and tendon properties (Morse CI, Thom JM, Birch KM, Narici MV. Acta Physiol Scand 183: 291-298, 2005; Narici MV, Maganaris CN, Reeves ND, Capodaglio P. J Appl Physiol 95: 2229-2234, 2003; Stenroth L, Peltonen J, Cronin NJ, Sipila S, Finni T. J Appl Physiol 113: 1537-1544, 2012). However, the possible influence of different types of regular exercise loading on muscle architecture and tendon properties in older adults is poorly understood. To address this, triceps surae muscle-tendon properties were examined in older male endurance (OE, n = 10, age = 74.0 ± 2.8 yr) and sprint runners (OS, n = 10, age = 74.4 ± 2.8 yr), with an average of 42 yr of regular training experience, and compared with age-matched [older control (OC), n = 33, age = 74.8 ± 3.6 yr] and young untrained controls (YC, n = 18, age = 23.7 ± 2.0 yr). Compared with YC, Achilles tendon cross-sectional area (CSA) was 22% (P = 0.022), 45% (P = 0.001), and 71% (P < 0.001) larger in OC, OE, and OS, respectively. Among older groups, OS had significantly larger tendon CSA compared with OC (P = 0.033). No significant between-group differences were observed in Achilles tendon stiffness. In older groups, Young's modulus was 31-44%, and maximal tendon stress 44-55% lower, than in YC (P ≤ 0.001). OE showed shorter soleus fascicle length than both OC (P < 0.05) and YC (P < 0.05). These data suggest that long-term running does not counteract the previously reported age-related increase in tendon CSA, but, instead, may have an additive effect. The greatest Achilles tendon CSA was observed in OS followed by OE and OC, suggesting that adaptation to running exercise is loading intensity dependent. Achilles tendon stiffness was maintained in older groups, even though all older groups displayed larger tendon CSA and lower tendon Young's modulus. Shorter soleus muscle fascicles in OE runners may be an adaptation to life

  8. Weight cycling in adolescent Taekwondo athletes

    PubMed Central

    Kazemi, Mohsen; Rahman, Alima; De Ciantis, Marco

    2011-01-01

    Background Weight reduction cycles are used by weight classed athletes in Taekwondo to make a weight category. Tension, dizziness, headaches, and confusion have been associated with rapid weight loss (RWL). There is a lack of research in weight cycling and its benefits among Taekwondo athletes. Purpose To investigate the rate of weight cycling in Junior Taekwondo athletes and its effect on performance. Methods Athletes were weighed prior to competition, then again before their first match. Body mass difference in relation to winning was compared. Results A significant increase from weigh-in to pre-match measurements was consistently found in both genders with no significant difference between them. Winners had a mean body mass gain (1.02 kg) which was non-significantly less than the non-winners (1.09 kg). Conclusions RWL practices do not define which athlete will perform better. Negative effects of weight cycling coupled with RWL has unclear performance benefits which indicates a need for further research. PMID:22131569

  9. Ephedra Use in a Select Group of Adolescent Athletes

    PubMed Central

    P. Schaefer, Michael; Smith, Jay; L. Dahm, Diane; C. Sorenson, Matthew

    2006-01-01

    Ephedra-containing dietary supplements are consumed to improve sports performace, but may carry risks of cardiac and neurological adverse events. Little is known of their use by young athletes. Our aim was to determine the prevalence and patterns of ephedra use among high school athletes. An anonymous survey was performed in Rochester, Minnesota on high school athletes who participated in fall sports during 2003-04. Parental consent was obtained for athletes under age 18 years. Surveys were distributed at preparticipation examinations and in- school survey stations. The response rate to the survey was 68.2%, or 311 respondents out of a possible 456 with consent (or 26% of all 1197 athletes eligible prior to the consent process). Seven of 311 (2.3%) respondents used dietary supplements containing ephedra. Only one of seven users (14.3%) knew that the supplements they used contained ephedra. Ephedra use was more common in boys (five) than girls (two). Ephedra use was only found in 17 and 18-year-olds. The most common sports among ephedra users were football, track and field, and weightlifting. This study suggests that Ephedra use was infrequent among the young athletes in this population. However, ephedra users were generally unaware that the dietary supplements they consumed contained ephedra. Users were more likely to participate in football, track and field, and weightlifting. Ephedra users were likely to obtain supplements from their peers, and were largely uninformed of the content of their supplements. Key Points Ephedra is an herbal stimulant used as an ergogenic aide. Adolescent ephedra users most commonly obtain it from their friends. Adolescent athletes are likely to take ephedra unknowningly. PMID:24353458

  10. Bone acquisition during adolescence in athletes.

    PubMed

    Markou, Kostas B; Theodoropoulou, Anastasia; Tsekouras, Athanasios; Vagenakis, Apostolos G; Georgopoulos, Neoklis A

    2010-09-01

    Bone mass (BM) and skeletal size are similar in prepubertal girls and boys and double between the onset of puberty and early adult life. Sex steroids are responsible for the maturation in human skeleton, as well as for the sexual dimorphism, observed after the onset of puberty. Physical activity in childhood is critical for maximizing bone growth and thus for preventing osteoporosis during older age. Therefore, it constitutes the most effective prevention strategy available. In athletes, high-impact loading activities have been shown to improve BM, whereas in sports requiring a lean somatotype (therefore leading to a negative energy balance), the delay in skeletal maturation and pubertal development predisposes athletes to osteopenia and osteoporosis. Although the early onset of training, the continuous intensive exercise and its long duration attenuate bone acquisition, the excess mechanical load to which these athletes are exposed from a young age exerts beneficial effects on bone formation that lead to a positive net-effect on BM.

  11. Adolescent elite athletes' cigarette smoking, use of snus, and alcohol.

    PubMed

    Martinsen, M; Sundgot-Borgen, J

    2014-04-01

    The purpose was to examine cigarette smoking, use of snus, alcohol, and performance-enhancing illicit drugs among adolescent elite athletes and controls, and possible gender and sport group differences. First-year students at 16 Norwegian Elite Sport High Schools (n = 677) and two randomly selected high schools (controls, n = 421) were invited to participate. Totally, 602 athletes (89%) and 354 (84%) controls completed the questionnaire. More controls than athletes were smoking, using snus, and drinking alcohol. Competing in team sports was associated with use of snus [odds ratio = 2.8, 95% confidence interval (CI) 1.6 to 4.7] and a similar percentage of male and female handball (22.2% vs 18.8%) and soccer players (15.7% vs 15.0%) reported using snus. For controls, not participating in organized sport was a predictor for smoking (odds ratio = 4.9, 95% CI 2.2 to 10.9). Female athletes were more prone to drink alcohol than males (46.3% vs 31.0%, P < 0.001). Only, 1.2% athletes and 2.8% controls reported use of performance-enhancing illicit drugs. In conclusion, use of legal drugs is less common among athletes, but this relationship depends on type of sport and competition level. The association between team sports and use of snus suggests that sport subcultures play a role.

  12. The Athletic Trainer's Role in Modifying Nutritional Behaviors of Adolescent Athletes: Putting Theory into Practice

    PubMed Central

    Hackman, Robert M.; Katra, Jane E.; Geertsen, Susan M.

    1992-01-01

    Nutritional practices influence athletic performance and recovery from injury. The athletic trainer is ideally positioned to effect dietary changes with adolescent athletes—a group at high-risk for nutritional imbalances. Research shows that young adults generally do not change dietary practices when given factual nutrition and health information. This article provides a variety of behavior change strategies, based on models derived from health education and health psychology, which are likely to influence dietary choices. Promoting self-efficacy by enhancing perception of choice and control, peer modeling, cooperative support networks, goal-setting techniques, and behavioral self-monitoring may provide the motivational framework necessary to enhance dietary compliance. Dietary behavior change techniques are a valuable part of an athletic trainer's resources. PMID:16558172

  13. Sprint profile of professional female soccer players during competitive matches: Female Athletes in Motion (FAiM) study.

    PubMed

    Vescovi, Jason D

    2012-01-01

    The aim of this study was to determine sprint profiles of professional female soccer players and evaluate how various speed thresholds impact those outcomes. Seventy-one professional players competing in full matches were assessed repeatedly during 12 regular season matches using a Global Positioning System (GPS). Locomotion ≥18 km · h⁻¹ was defined as sprinting and each event was classified into: Zone 1: 18.0-20.9 km· h⁻¹; Zone 2: 21.0-22.9 km · h⁻¹; Zone 3: 23.0-24.9 km · h⁻¹ and Zone 4: >25 km · h⁻¹. Outcomes included: duration (s), distance (m), maximum speed (km · h⁻¹), duration since previous sprint (min) and proportion of total sprint distance. In total 5,019 events were analysed from 139 player-matches. Mean sprint duration, distance, maximum speed and time between sprints were 2.3 ± 1.5 s, 15.1 ± 9.4 m, 21.8 ± 2.3 km· h⁻¹, and 2.5 ± 2.5 min, respectively. Mean sprint distances were 657 ± 157, 447 ± 185, and 545 ± 217 m for forwards, midfielders and defenders, respectively (P ≤ 0.046). Midfielders had shorter sprint duration (P = 0.023), distance (P ≤ 0.003) and maximum speed (P < 0.001), whereas forwards performed more sprints per match (43 ± 10) than midfielders (31 ± 11) and defenders (36 ± 12) (P ≤ 0.016). Forty-five percent, 29%, 15%, and 11% of sprints occurred in sprint Zones 1, 2, 3 and 4, respectively. This group of professional female soccer players covered 5.3 ± 2.0% of total distance ≥18 km · h⁻¹ with positional differences and percent decrements distinct from other previously identified elite players. These data should guide the development of high intensity and sprint thresholds for elite-standard female soccer players.

  14. Tendon Adaptation to Sport-specific Loading in Adolescent Athletes.

    PubMed

    Cassel, M; Carlsohn, A; Fröhlich, K; John, M; Riegels, N; Mayer, F

    2016-02-01

    Tendon adaptation due to mechanical loading is controversially discussed. However, data concerning the development of tendon thickness in adolescent athletes is sparse. The purpose of this study was to examine possible differences in Achilles (AT) and patellar tendon (PT) thickness in adolescent athletes while considering age, gender and sport-specific loading. In 500 adolescent competitive athletes of 16 different sports and 40 recreational controls both ATs and PTs were sonographically measured. Subjects were divided into 2 age groups (< 13; ≥ 13 years) and 6 sport type categories (ball, combat, and water sports, combined disciplines, cycling, controls). In addition, 3 risk groups (low, moderate, high) were created according to the athlete's risk of developing tendinopathy. AT and PT thickness did not significantly differ between age groups (AT/PT:<13: 5.4±0.7 mm/3.6±0.5 mm;≥13: 5.3±0.7 mm/3.6±0.5 mm). In both age groups males presented higher tendon thickness than females (p<0.001). AT thickness was highest in ball sports/cyclists and lowest in controls (p≤0.002). PT thickness was greatest in water sports and lowest in controls (p=0.02). High risk athletes presented slightly higher AT thickness compared to the low risk group (p=0.03). Increased AT and PT thickness in certain sport types compared to controls supports the hypothesis of structural tendon adaptation due to sport-specific loading.

  15. Rehabilitation programs and prevention strategies in adolescent throwing athletes.

    PubMed

    McFarland, Edward G; Ireland, Mary Lloyd

    2003-01-01

    A specific and early diagnosis must be made in the injured skeletally immature throwing athlete. A well-outlined program of rest, rehabilitation, and proper throwing techniques should be implemented and continued. Overuse injuries are preventable when biomechanics are sound and pitch counts are done with the limits enforced. Guidelines for inning limits, number of pitches, rest intervals, and throwing programs should be followed for adolescent pitchers because adolescents differ from adults. Information is included for specifications of the ball and helmet, as well as chest protective equipment. The goal should be for the Little League players to have fun and be injury free as they are competing, which gives them the best experience and allows continuation of athletic activities for a lifetime.

  16. Peri-epiphyseal and Overuse Injuries in Adolescent Athletes

    PubMed Central

    Frush, Todd J.; Lindenfeld, Thomas N.

    2009-01-01

    Context: Overuse injuries of the musculoskeletal system in immature athletes are commonly seen in medical practice. Evidence Acquisition: An analysis of published clinical, outcome, and biomechanical studies of adolescent epiphyseal and overuse injuries was performed through 2008 to increase recognition and provide treatment recommendations. Results: Adolescent athletes can sustain physeal and bony stress injuries. Recovery and return to play occur more swiftly if such injuries are diagnosed early and immobilized until the patient is pain-free, typically about 4 weeks for apophyseal and epiphyseal overuse injuries. Certain epiphyseal injuries have prolonged symptoms with delayed treatment, including those involving the bones in the hand, elbow, and foot. If such injuries are missed, prolonged healing and significant restrictions in athletic pursuits may occur. Conclusion: Some of these injuries are common to all weightbearing sports and are therefore widely recognized. Several are common in gymnastics but are rarely seen in other athletes. Early recognition and treatment of these conditions lead to quicker recovery and so may prevent season-ending, even career-ending, events from occurring. PMID:23015873

  17. Cortical desmoids in adolescent top-level athletes

    PubMed Central

    Biedert, Roland M; Gal, Imre

    2015-01-01

    Two adolescent, highly active athletes are presented with unspecific symptoms of anterior knee pain. Conventional radiographs and magnetic resonance imaging (MRI) showed a suspicious but pathognomonic cortical irregularity of the dorsal, medial femoral condyle. Cortical desmoid is one of the most common incidental osseous findings on conventional radiographs and MRI of the knee. It often needs no follow-up examination in asymptomatic patients. Malignancy needs however to be ruled out. PMID:25992301

  18. Comparison of bone mineral density between athletic and non-athletic Chinese male adolescents.

    PubMed

    Tsai, S C; Kao, C H; Wang, S J

    1996-10-01

    For the evaluation of the effect of exercise on bone mineral density of adolescent athletes, twenty-nine Chinese male adolescent athletes, each of whom had regular training in his major sport which included baseball, swimming, judo and middle/long-distance running for one to six years and eight age-matched non-athletic controls were included in this study. Bone mineral density (BMD) was measured in all study subjects using dual photo absorptiometry at the second to fourth lumbar spines (L2-4) and the right femoral neck (FN). The results revealed the following: (1) the combined group of athletes had significantly greater BMD of L2-4 (1.08 +/- 0.09 g/cm2) than the control group (0.99 +/- 0.08 g/cm2) and a tendency for greater BMD of FN (1.15 +/- 0.13 g/cm2) than the control group (1.09 +/- 0.13 g/cm2); (2) judo majors had significantly greater BMD of L2-4 than baseball majors (P < 0.05), swimming majors (P < 0.01), track majors (P < 0.05) and controls (P < 0.005); (3) baseball majors had significantly greater BMD of L2-4 than controls (P < 0.05) and greater BMD of FN than swimming majors (P < 0.05), judo majors (P < 0.05), track majors (P < 0.005) and controls (P < 0.005); (4) body weight and body mass index (BMI) had good correlation with BMD of L2-4 and FN in control group, (5) in the combined group of athletes, weight and BMI were only strongly linked to BMD of FN, and not to BMD of L2-4. There was no good correlation between BMI and BMD of L2-4 and FN in any group of athletes. We concluded that (1) physical activity during adolescence may contribute significantly towards increasing BMD of athletes and (2) the training type may provide a specific stimulus for increasing BMD at specific localized sites experienced in training.

  19. Physiological, biomechanical and anthropometrical predictors of sprint swimming performance in adolescent swimmers.

    PubMed

    Lätt, Evelin; Jürimäe, Jaak; Mäestu, Jarek; Purge, Priit; Rämson, Raul; Haljaste, Kaja; Keskinen, Kari L; Rodriguez, Ferran A; Jürimäe, Toivo

    2010-01-01

    The purpose of this study was to analyze the relationships between 100-m front crawl swimming performance and relevant biomechanical, anthropometrical and physiological parameters in male adolescent swimmers. Twenty five male swimmers (mean ± SD: age 15. 2 ± 1.9 years; height 1.76 ± 0.09 m; body mass 63.3 ± 10.9 kg) performed an all-out 100-m front crawl swimming test in a 25-m pool. A respiratory snorkel and valve system with low hydrodynamic resistance was used to collect expired air. Oxygen uptake was measured breath-by-breath by a portable metabolic cart. Swimming velocity, stroke rate (SR), stroke length and stroke index (SI) were assessed during the test by time video analysis. Blood samples for lactate measurement were taken from the fingertip pre exercise and at the third and fifth minute of recovery to estimate net blood lactate accumulation (ΔLa). The energy cost of swimming was estimated from oxygen uptake and blood lactate energy equivalent values. Basic anthropometry included body height, body mass and arm span. Body composition parameters were measured using dual-energy X-ray absorptiometry (DXA). Results indicate that biomechanical factors (90.3%) explained most of 100-m front crawl swimming performance variability in these adolescent male swimmers, followed by anthropometrical (45.8%) and physiological (45.2%) parameters. SI was the best single predictor of performance, while arm span and ∆La were the best anthropometrical and physiological indicators, respectively. SI and SR alone explained 92.6% of the variance in competitive performance. These results confirm the importance of considering specific stroke technical parameters when predicting success in young swimmers. Key pointsThis study investigated the influence of different anthropometrical, physiological and biomechanical parameters on 100-m swimming performance in adolescent boys.Biomechanical factors contributed most to sprint swimming performance in these young male swimmers (90

  20. Physiological, Biomechanical and Anthropometrical Predictors of Sprint Swimming Performance in Adolescent Swimmers

    PubMed Central

    Lätt, Evelin; Jürimäe, Jaak; Mäestu, Jarek; Purge, Priit; Rämson, Raul; Haljaste, Kaja; Keskinen, Kari L.; Rodriguez, Ferran A.; Jürimäe, Toivo

    2010-01-01

    The purpose of this study was to analyze the relationships between 100-m front crawl swimming performance and relevant biomechanical, anthropometrical and physiological parameters in male adolescent swimmers. Twenty five male swimmers (mean ± SD: age 15. 2 ± 1.9 years; height 1.76 ± 0.09 m; body mass 63.3 ± 10.9 kg) performed an all-out 100-m front crawl swimming test in a 25-m pool. A respiratory snorkel and valve system with low hydrodynamic resistance was used to collect expired air. Oxygen uptake was measured breath-by-breath by a portable metabolic cart. Swimming velocity, stroke rate (SR), stroke length and stroke index (SI) were assessed during the test by time video analysis. Blood samples for lactate measurement were taken from the fingertip pre exercise and at the third and fifth minute of recovery to estimate net blood lactate accumulation (ΔLa). The energy cost of swimming was estimated from oxygen uptake and blood lactate energy equivalent values. Basic anthropometry included body height, body mass and arm span. Body composition parameters were measured using dual-energy X-ray absorptiometry (DXA). Results indicate that biomechanical factors (90.3%) explained most of 100-m front crawl swimming performance variability in these adolescent male swimmers, followed by anthropometrical (45.8%) and physiological (45.2%) parameters. SI was the best single predictor of performance, while arm span and ∆La were the best anthropometrical and physiological indicators, respectively. SI and SR alone explained 92.6% of the variance in competitive performance. These results confirm the importance of considering specific stroke technical parameters when predicting success in young swimmers. Key points This study investigated the influence of different anthropometrical, physiological and biomechanical parameters on 100-m swimming performance in adolescent boys. Biomechanical factors contributed most to sprint swimming performance in these young male swimmers (90

  1. Greater trochanter apophysitis in the adolescent athlete.

    PubMed

    Young, Simon W; Safran, Marc R

    2015-05-01

    Lower limb traction apophysitis is common in young athletes, occurring at sites such as the tibial tubercle (Osgood-Schlatter disease) and distal patella (Sinding-Larsen-Johansson disease). Around the hip, iliac apophysitis is well recognized, but no cases of greater trochanter apophysitis have previously been reported. We describe the case of a 15-year-old male basketball player with a 2-month history of the right hip pain and significant functional limitation. X-rays revealed widening of the greater trochanter apophysis with subchondral sclerosis, consistent with a diagnosis of traction apophysitis. The patient was treated with a period of relative rest and anti-inflammatory medication. He gradually returned to full athletic activity, including basketball, without recurrence of pain or limitation. We describe the first reported case of traction apophysitis of the greater trochanter. The unique muscular anatomy of this apophysis with balanced forces explains the rarity of this condition. If encountered, rest and activity modification is the recommended treatment.

  2. An athletic adolescent girl with proteinuria and hypertension.

    PubMed

    Dante, Siddhartha; Glunz, Catherine

    2015-03-01

    An 18-year-old athletic adolescent presents with hypertension found during a routine screening. Her prior history includes familial hyperlipidemia. Hypertension in the adolescent is classified based on percentiles for age, sex, and height. The most common secondary cause of hypertension in the pediatric and adolescent patient is renal disease. This patient was found to have nephrotic syndrome and because of her age, a renal biopsy was required to make the diagnosis and to direct subsequent treatment plans. She was diagnosed with C3 glomerulopathy, which is the result of dysregulation and uncontrolled activation of the alternative complement pathway; new therapies are emerging for this disease. In this case, we review the diagnosis and initial assessment of hypertension in the pediatric patient, and the causes of nephrotic syndrome with a focus on C3 glomerulopathy.

  3. [Doping and performance among adolescent athletes].

    PubMed

    Zorzoli, Mario

    2003-02-01

    If doping is generally considered a phenomena of the sports world, the use of substances to achieve a better performance is an attitude which is rapidly spreading out in our society. Doping behavior is defined as the consumption of a product in order to face or pass an obstacle and be more performant. Even among adolescents, the will to increase the efficiency in sport or to modify the body appearance, push some people to use any kind of products: nutritional supplements, doping agents (anabolic steroids, amphetamines, etc.), with all the associated risks due to the doubtful origin of some of these substances, the way they are consumed or their side effects. It is important that the medical community, and those who are in contact with the adolescents, realize that this kind of behavior exists, so to face it in an adequately manner, the same way they deal with the problem of alcohol, tobacco or drugs.

  4. An individualized longitudinal approach to monitoring the dynamics of growth and fitness development in adolescent athletes.

    PubMed

    Till, Kevin; Cobley, Steve; Oʼhara, John; Chapman, Chris; Cooke, Carlton

    2013-05-01

    This study evaluated the development of anthropometric and fitness characteristics of 3 individual adolescent junior rugby league players and compared their characteristics with a cross-sectional population matched by age and skill level. Cross-sectional anthropometric and fitness assessments were conducted on 1,172 players selected to the Rugby Football League's talent development program (i.e., the Player Performance Pathway) between 2005 and 2008. Three players of differing relative age, maturational status, and playing position were measured and tracked once per year on 3 occasions (Under 13s, 14s, 15s age categories) and compared against the cross-sectional population. Results demonstrated that the later maturing players increased height (player 1 = 9.2%; player 2 = 7.8%) and a number of fitness characteristics (e.g., 60-m speed-player 1 = -14.9%; player 2 = -9.9%) more than the earlier maturing player (player 3-Height = 2.0%, 60-m sprint = -0.7%) over the 2-year period. The variation in the development of anthropometric and fitness characteristics between the 3 players highlights the importance of longitudinally monitoring individual characteristics during adolescence to assess the dynamic changes in growth, maturation, and fitness. Findings showcase the limitations of short-term performance assessments at one-off time points within annual-age categories, instead of advocating individual development and progression tracking without deselection. Coaches should consider using an individual approach, comparing data with population averages, to assist in the prescription of appropriate training and lifestyle interventions to aid the development of junior athletes.

  5. Effects of In-Water Passive Recovery on Sprint Swimming Performance and Heart Rate in Adolescent Swimmers

    PubMed Central

    Casuso, Rafael A.; Martínez-López, Emilio; Hita-Contreras, Fidel; Ruiz-Cazalilla, Irene; Cruz-Díaz, David; Martínez-Amat, Antonio

    2014-01-01

    The aim of the present study is to test the hypothesis that sprint swimming performance is enhanced by in-water passive recovery (IN) after sprint swimming bouts in well-trained adolescent swimmers. Using a randomized crossover study design, twelve well-trained adolescent swimmers performed two tests at the swimming pool after preliminary testing. They performed 5 bouts of 100m all-out swimming separated by 5 minutes of passive rest. Their individual in- or out-of-water passive recovery condition was randomized on the first day. In their second visit to the swimming pool the opposite recovery condition was indicated. More than 60% of the subjects which rested in-water were faster in the 5th bout when compared to the OUT group. However, no significant differences were found in blood lactate when IN and OUT were compared. After the first bout peak heart rate (HR peak) was lower in subsequent bouts for IN recovery when compared with OUT (p < 0.001). Thus, coaches and researchers should take into account that IN passive recovery may decrease loss of performance and diminish HR peak during sprint swimming bouts. This is particularly important given the use that many coaches give to HR as a tool in daily training. Key points In-water passive recovery minimizes the loss of performance during high intensity swimming Maximal HR is significantly reduced by in-water recovery Coaches should take this information into account when using HR to control swimming intensity Future research should study long-term effects induced by in-water passive recovery PMID:25435791

  6. Effects of in-water passive recovery on sprint swimming performance and heart rate in adolescent swimmers.

    PubMed

    Casuso, Rafael A; Martínez-López, Emilio; Hita-Contreras, Fidel; Ruiz-Cazalilla, Irene; Cruz-Díaz, David; Martínez-Amat, Antonio

    2014-12-01

    The aim of the present study is to test the hypothesis that sprint swimming performance is enhanced by in-water passive recovery (IN) after sprint swimming bouts in well-trained adolescent swimmers. Using a randomized crossover study design, twelve well-trained adolescent swimmers performed two tests at the swimming pool after preliminary testing. They performed 5 bouts of 100m all-out swimming separated by 5 minutes of passive rest. Their individual in- or out-of-water passive recovery condition was randomized on the first day. In their second visit to the swimming pool the opposite recovery condition was indicated. More than 60% of the subjects which rested in-water were faster in the 5th bout when compared to the OUT group. However, no significant differences were found in blood lactate when IN and OUT were compared. After the first bout peak heart rate (HR peak) was lower in subsequent bouts for IN recovery when compared with OUT (p < 0.001). Thus, coaches and researchers should take into account that IN passive recovery may decrease loss of performance and diminish HR peak during sprint swimming bouts. This is particularly important given the use that many coaches give to HR as a tool in daily training. Key pointsIn-water passive recovery minimizes the loss of performance during high intensity swimmingMaximal HR is significantly reduced by in-water recoveryCoaches should take this information into account when using HR to control swimming intensityFuture research should study long-term effects induced by in-water passive recovery.

  7. Effects of in-water passive recovery on sprint swimming performance and heart rate in adolescent swimmers.

    PubMed

    Casuso, Rafael A; Martínez-López, Emilio; Hita-Contreras, Fidel; Ruiz-Cazalilla, Irene; Cruz-Díaz, David; Martínez-Amat, Antonio

    2014-12-01

    The aim of the present study is to test the hypothesis that sprint swimming performance is enhanced by in-water passive recovery (IN) after sprint swimming bouts in well-trained adolescent swimmers. Using a randomized crossover study design, twelve well-trained adolescent swimmers performed two tests at the swimming pool after preliminary testing. They performed 5 bouts of 100m all-out swimming separated by 5 minutes of passive rest. Their individual in- or out-of-water passive recovery condition was randomized on the first day. In their second visit to the swimming pool the opposite recovery condition was indicated. More than 60% of the subjects which rested in-water were faster in the 5th bout when compared to the OUT group. However, no significant differences were found in blood lactate when IN and OUT were compared. After the first bout peak heart rate (HR peak) was lower in subsequent bouts for IN recovery when compared with OUT (p < 0.001). Thus, coaches and researchers should take into account that IN passive recovery may decrease loss of performance and diminish HR peak during sprint swimming bouts. This is particularly important given the use that many coaches give to HR as a tool in daily training. Key pointsIn-water passive recovery minimizes the loss of performance during high intensity swimmingMaximal HR is significantly reduced by in-water recoveryCoaches should take this information into account when using HR to control swimming intensityFuture research should study long-term effects induced by in-water passive recovery. PMID:25435791

  8. Effect of a carbohydrate-protein multi-ingredient supplement on intermittent sprint performance and muscle damage in recreational athletes.

    PubMed

    Naclerio, Fernando; Larumbe-Zabala, Eneko; Cooper, Robert; Jimenez, Alfonso; Goss-Sampson, Mark

    2014-10-01

    Carbohydrate-protein-based multi-ingredient supplements have been proposed as an effective strategy for limiting the deleterious effects of exercise-induced muscle damage. This study compares the effects of a commercially available carbohydrate-protein supplement enriched with l-glutamine and l-carnitine-l-tartrate to carbohydrate alone or placebo on sprint performance, muscle damage markers, and recovery from intermittent exercise. On 3 occasions, 10 recreationally trained males ingested a multi-ingredient, a carbohydrate supplement, or a placebo before, during, and immediately after a 90-min intermittent repeated sprint test. Fifteen-metre sprint times, creatine kinase, myoglobin, and interleukin-6 were assessed before (pre), immediately after (post), 1 h after (1h), and 24 h after (24h) exercise. Total sprint time measured during the intermittent protocol was not different between conditions. Fifteen-metre sprint time was slower (p < 0.05) at post, 1h and 24h compared with pre without differences between conditions (p > 0.05). Creatine kinase at 24h was lower (p < 0.05) in the multi-ingredient (461.8 ± 271.8 U·L) compared with both carbohydrate and placebo (606 ± 314.5 U·L and 636 ± 344.6 U·L, respectively). Myoglobin increased (p < 0.05) in all 3 conditions at post and 1h compared with pre, showing lower values at 1h (p < 0.05) for the carbohydrate and a trend (p = 0.060) for multi-ingredient compared with the placebo condition (211.4 ± 127.2 ng·mL(-1) and 239.4 ± 103.8 ng·mL(-1) vs. 484.6 ± 200.0 ng·mL(-1), respectively). Interleukin-6 increased at both post and 1h compared with pre (p < 0.05) with no differences between conditions. In conclusion, ingesting a multi-ingredient supplement before, during, and immediately after a 90-min intermittent sprint test resulted in no effects on performance and fatigue while the accumulation of some biomarkers of muscle damage could be attenuated. PMID:25029675

  9. Dietary Intakes and Supplement Use in Pre-Adolescent and Adolescent Canadian Athletes.

    PubMed

    Parnell, Jill A; Wiens, Kristin P; Erdman, Kelly A

    2016-01-01

    Young athletes experience numerous dietary challenges including growth, training/competition, unhealthy food environments, and travel. The objective was to determine nutrient intakes and supplement use in pre-adolescent and adolescent Canadian athletes. Athletes (n = 187) aged 11-18 years completed an on-line 24-h food recall and dietary supplement questionnaire. Median energy intake (interquartile range) varied from 2159 kcal/day (1717-2437) in 11-13 years old females to 2905 kcal/day (2291-3483) in 14-18 years old males. Carbohydrate and protein intakes were 8.1 (6.1-10.5); 2.4 (1.6-3.4) in males 11-13 years, 5.7 (4.5-7.9); 2.0 (1.4-2.6) in females 11-13 years, 5.3 (4.3-7.4); 2.0 (1.5-2.4) in males 14-18 y and 4.9 (4.4-6.2); 1.7 (1.3-2.0) in females 14-18 years g/kg of body weight respectively. Median vitamin D intakes were below the recommended dietary allowance (RDA) and potassium was below the adequate intake (AI) for all athlete groups. Females 14-18 years had intakes below the RDA for iron 91% (72-112), folate 89% (61-114) and calcium 84% (48-106). Multivitamin-multiminerals, vitamin C, vitamin D, vitamin-enriched water, protein powder, sport foods, fatty acids, probiotics, and plant extracts were popular supplements. Canadian pre-adolescent and adolescent athletes could improve their dietary intakes by focusing on food sources of calcium, vitamin D, potassium, iron, and folate. With the exceptions of vitamin D and carbohydrates during long exercise sessions, supplementation is generally unnecessary.

  10. Dietary Intakes and Supplement Use in Pre-Adolescent and Adolescent Canadian Athletes.

    PubMed

    Parnell, Jill A; Wiens, Kristin P; Erdman, Kelly A

    2016-01-01

    Young athletes experience numerous dietary challenges including growth, training/competition, unhealthy food environments, and travel. The objective was to determine nutrient intakes and supplement use in pre-adolescent and adolescent Canadian athletes. Athletes (n = 187) aged 11-18 years completed an on-line 24-h food recall and dietary supplement questionnaire. Median energy intake (interquartile range) varied from 2159 kcal/day (1717-2437) in 11-13 years old females to 2905 kcal/day (2291-3483) in 14-18 years old males. Carbohydrate and protein intakes were 8.1 (6.1-10.5); 2.4 (1.6-3.4) in males 11-13 years, 5.7 (4.5-7.9); 2.0 (1.4-2.6) in females 11-13 years, 5.3 (4.3-7.4); 2.0 (1.5-2.4) in males 14-18 y and 4.9 (4.4-6.2); 1.7 (1.3-2.0) in females 14-18 years g/kg of body weight respectively. Median vitamin D intakes were below the recommended dietary allowance (RDA) and potassium was below the adequate intake (AI) for all athlete groups. Females 14-18 years had intakes below the RDA for iron 91% (72-112), folate 89% (61-114) and calcium 84% (48-106). Multivitamin-multiminerals, vitamin C, vitamin D, vitamin-enriched water, protein powder, sport foods, fatty acids, probiotics, and plant extracts were popular supplements. Canadian pre-adolescent and adolescent athletes could improve their dietary intakes by focusing on food sources of calcium, vitamin D, potassium, iron, and folate. With the exceptions of vitamin D and carbohydrates during long exercise sessions, supplementation is generally unnecessary. PMID:27571101

  11. Dietary Intakes and Supplement Use in Pre-Adolescent and Adolescent Canadian Athletes

    PubMed Central

    Parnell, Jill A.; Wiens, Kristin P.; Erdman, Kelly A.

    2016-01-01

    Young athletes experience numerous dietary challenges including growth, training/competition, unhealthy food environments, and travel. The objective was to determine nutrient intakes and supplement use in pre-adolescent and adolescent Canadian athletes. Athletes (n = 187) aged 11–18 years completed an on-line 24-h food recall and dietary supplement questionnaire. Median energy intake (interquartile range) varied from 2159 kcal/day (1717–2437) in 11–13 years old females to 2905 kcal/day (2291–3483) in 14–18 years old males. Carbohydrate and protein intakes were 8.1 (6.1–10.5); 2.4 (1.6–3.4) in males 11–13 years, 5.7 (4.5–7.9); 2.0 (1.4–2.6) in females 11–13 years, 5.3 (4.3–7.4); 2.0 (1.5–2.4) in males 14–18 y and 4.9 (4.4–6.2); 1.7 (1.3–2.0) in females 14–18 years g/kg of body weight respectively. Median vitamin D intakes were below the recommended dietary allowance (RDA) and potassium was below the adequate intake (AI) for all athlete groups. Females 14–18 years had intakes below the RDA for iron 91% (72–112), folate 89% (61–114) and calcium 84% (48–106). Multivitamin-multiminerals, vitamin C, vitamin D, vitamin-enriched water, protein powder, sport foods, fatty acids, probiotics, and plant extracts were popular supplements. Canadian pre-adolescent and adolescent athletes could improve their dietary intakes by focusing on food sources of calcium, vitamin D, potassium, iron, and folate. With the exceptions of vitamin D and carbohydrates during long exercise sessions, supplementation is generally unnecessary. PMID:27571101

  12. Reliability of the Spatiotemporal Determinants of Maximal Sprint Speed in Adolescent Boys Over Single and Multiple Steps.

    PubMed

    Meyers, Robert W; Oliver, Jon L; Hughes, Michael G; Lloyd, Rhodri Steffan; Cronin, John

    2015-08-01

    The purpose of this study was to examine the reliability of the spatiotemporal determinants of maximal sprinting speed in boys over single and multiple steps. Fifty-four adolescent boys (age = 14.1 ± 0.7 years [range = 12.9-15.7 years]; height = 1.63 ± 0.09 m; body mass = 55.3 ± 13.3 kg; -0.31 ± 0.90 age from Peak Height Velocity (PHV) in years; mean ± s) volunteered to complete a 30 m sprint test on 3 occasions over a 2-week period. Speed, step length, step frequency, contact time, and flight time were assessed via an optical measurement system. Speed and step characteristics were obtained from the single-fastest step and average of the 2 and 4 fastest consecutive steps. Pairwise comparison of consecutive trials revealed the coefficient of variation (CV) for speed was greater in 4-step (CV = 7.3 & 7.5%) compared with 2-step (CV = 4.2 & 4.1%) and 1-step (CV = 4.8 & 4.6%) analysis. The CV of step length, step frequency and contact time ranged from 4.8 to 7.5% for 1-step, 3.8-5.0% for 2-step and 4.2-7.5% for 4-step analyses across all trials. An acceptable degree of reliability was achieved for the spatiotemporal and performance variables assessed in this study. Two-step analysis demonstrated the highest degree of reliability for the key spatiotemporal variables, and therefore may be the most suitable approach to monitor the spatiotemporal characteristics of maximal sprint speed in boys.

  13. Sports Dietitians Australia position statement: sports nutrition for the adolescent athlete.

    PubMed

    Desbrow, Ben; McCormack, Joanna; Burke, Louise M; Cox, Gregory R; Fallon, Kieran; Hislop, Matthew; Logan, Ruth; Marino, Nello; Sawyer, Susan M; Shaw, Greg; Star, Anita; Vidgen, Helen; Leveritt, Michael

    2014-10-01

    It is the position of Sports Dietitians Australia (SDA) that adolescent athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the demands of growth and development. As such, SDA established an expert multidisciplinary panel to undertake an independent review of the relevant scientific evidence and consulted with its professional members to develop sports nutrition recommendations for active and competitive adolescent athletes. The position of SDA is that dietary education and recommendations for these adolescent athletes should reinforce eating for long term health. More specifically, the adolescent athlete should be encouraged to moderate eating patterns to reflect daily exercise demands and provide a regular spread of high quality carbohydrate and protein sources over the day, especially in the period immediately after training. SDA recommends that consideration also be given to the dietary calcium, Vitamin D and iron intake of adolescent athletes due to the elevated risk of deficiency of these nutrients. To maintain optimal hydration, adolescent athletes should have access to fluids that are clean, cool and supplied in sufficient quantities before, during and after participation in sport. Finally, it is the position of SDA that nutrient needs should be met by core foods rather than supplements, as the recommendation of dietary supplements to developing athletes over-emphasizes their ability to manipulate performance in comparison with other training and dietary strategies. PMID:24668620

  14. Sports Dietitians Australia position statement: sports nutrition for the adolescent athlete.

    PubMed

    Desbrow, Ben; McCormack, Joanna; Burke, Louise M; Cox, Gregory R; Fallon, Kieran; Hislop, Matthew; Logan, Ruth; Marino, Nello; Sawyer, Susan M; Shaw, Greg; Star, Anita; Vidgen, Helen; Leveritt, Michael

    2014-10-01

    It is the position of Sports Dietitians Australia (SDA) that adolescent athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the demands of growth and development. As such, SDA established an expert multidisciplinary panel to undertake an independent review of the relevant scientific evidence and consulted with its professional members to develop sports nutrition recommendations for active and competitive adolescent athletes. The position of SDA is that dietary education and recommendations for these adolescent athletes should reinforce eating for long term health. More specifically, the adolescent athlete should be encouraged to moderate eating patterns to reflect daily exercise demands and provide a regular spread of high quality carbohydrate and protein sources over the day, especially in the period immediately after training. SDA recommends that consideration also be given to the dietary calcium, Vitamin D and iron intake of adolescent athletes due to the elevated risk of deficiency of these nutrients. To maintain optimal hydration, adolescent athletes should have access to fluids that are clean, cool and supplied in sufficient quantities before, during and after participation in sport. Finally, it is the position of SDA that nutrient needs should be met by core foods rather than supplements, as the recommendation of dietary supplements to developing athletes over-emphasizes their ability to manipulate performance in comparison with other training and dietary strategies.

  15. Phase angle and bioelectrical impedance vectors in adolescent and adult male athletes.

    PubMed

    Koury, Josely C; Trugo N, M F; Torres, Alexandre G

    2014-09-01

    The aim of the current study was to assess phase angle (PA) and bioelectrical impedance vectors (BIVA) in adolescent (n = 105, 12-19 y) and adult (n = 90, 20-50 y) male athletes practicing varied sports modalities. Bioelectrical impedance analysis (BIA) was performed with a single-frequency tetrapolar impedance analyzer after the athletes had fasted overnight for 8 h. PA and BIVA were determined from BIA data. PA presented correlations (P < .01) with body-mass index (r = .58) in all athletes and also with age in adolescent (r = .63) and adult (r = -.27) athletes. Compared with adults, adolescent athletes presented lower PA and higher frequency of PA below the 5th percentile of a reference population (P < .001). The adolescents with low PA were mostly football and basketball players. The BIVA confidence ellipses of adult and adolescent athletes were different (P < .001) between them and from their respective reference populations and were closer than those of adult and adolescent nonathletes. About 80% of the athletes were in the 95th percentile of BIVA tolerance ellipses and in quadrants consistent with adequate body cell mass and total body water. The adolescent athletes outside the 95th percentile ellipse were all football and basketball players who showed indications of decreased water retention and body cell mass and of increased water retention, respectively. PA and BIVA ellipses showed that the intense training routine of the athletes changed functional and hydration parameters and that the magnitude of these changes in adolescents may depend on the sport modality practiced.

  16. Motivational Cluster Profiles of Adolescent Athletes: An Examination of Differences in Physical-Self Perception

    PubMed Central

    Çağlar, Emine; Aşçı, F. Hülya

    2010-01-01

    The primary purpose of the present study was to identify motivational profiles of adolescent athletes using cluster analysis in non-Western culture. A second purpose was to examine relationships between physical self-perception differences of adolescent athletes and motivational profiles. One hundred and thirty six male (Mage = 17.46, SD = 1.25 years) and 80 female adolescent athletes (Mage = 17.61, SD = 1.19 years) from a variety of team sports including basketball, soccer, volleyball, and handball volunteered to participate in this study. The Sport Motivation Scale (SMS) and Physical Self-Perception Profile (PSPP) were administered to all participants. Hierarchical cluster analysis revealed a four-cluster solution for this sample: amotivated, low motivated, moderate motivated, and highly motivated. A 4 x 5 (Cluster x PSPP Subscales) MANOVA revealed no significant main effect of motivational clusters on physical self-perception levels (p > 0.05). As a result, findings of the present study showed that motivational types of the adolescent athletes constituted four different motivational clusters. Highly and moderate motivated athletes consistently scored higher than amotivated athletes on the perceived sport competence, physical condition, and physical self-worth subscales of PSPP. This study identified motivational profiles of competitive youth-sport participants. Key points Highly motivated athletes have a tendency to perceive themselves competent in psychomotor domains as compared to the amotivated athletes As the athletes feel more competent in psychomotor domain, they are more intrinsically motivated. The information about motivational profiles of adolescent athletes could be used for developing strategies and interventions designed to improve the strength and quality of sport participants’ motivation. PMID:24149690

  17. Motivational cluster profiles of adolescent athletes: an examination of differences in physical-self perception.

    PubMed

    Cağlar, Emine; Aşçı, F Hülya

    2010-01-01

    The primary purpose of the present study was to identify motivational profiles of adolescent athletes using cluster analysis in non-Western culture. A second purpose was to examine relationships between physical self-perception differences of adolescent athletes and motivational profiles. One hundred and thirty six male (Mage = 17.46, SD = 1.25 years) and 80 female adolescent athletes (Mage = 17.61, SD = 1.19 years) from a variety of team sports including basketball, soccer, volleyball, and handball volunteered to participate in this study. The Sport Motivation Scale (SMS) and Physical Self-Perception Profile (PSPP) were administered to all participants. Hierarchical cluster analysis revealed a four-cluster solution for this sample: amotivated, low motivated, moderate motivated, and highly motivated. A 4 x 5 (Cluster x PSPP Subscales) MANOVA revealed no significant main effect of motivational clusters on physical self-perception levels (p > 0.05). As a result, findings of the present study showed that motivational types of the adolescent athletes constituted four different motivational clusters. Highly and moderate motivated athletes consistently scored higher than amotivated athletes on the perceived sport competence, physical condition, and physical self-worth subscales of PSPP. This study identified motivational profiles of competitive youth-sport participants. Key pointsHighly motivated athletes have a tendency to perceive themselves competent in psychomotor domains as compared to the amotivated athletesAs the athletes feel more competent in psychomotor domain, they are more intrinsically motivated.The information about motivational profiles of adolescent athletes could be used for developing strategies and interventions designed to improve the strength and quality of sport participants' motivation.

  18. The contribution of step characteristics to sprint running performance in high-level male and female athletes.

    PubMed

    Debaere, Sofie; Jonkers, Ilse; Delecluse, Christophe

    2013-01-01

    We investigated the interaction between step length and step rate and its effect on sprint performance in male and female sprinters during initial acceleration (IA) (0-10 m), transition phase (TP) (10-30 m), and at maximal speed (MS). Ten high-level male and female sprinters ran 2 all-out 60-m sprints. Force-time characteristics of start action were recorded by means of instrumented starting blocks. Running speed and acceleration were recorded using a laser system (ULS), whereas step length and step rate were measured for each step (Optojump). Step length was normalized for leg length. Explosive strength of the lower limb muscles was quantified using vertical jump performance, showing a 24.6% higher score in men compared with women. During the 3 phases of sprinting, step rate remained constant and did not differ significantly between men (IA: 4.37 ± 0.21 Hz, TP: 4.47 ± 0.25 Hz, MS: 4.43 ± 0.18 Hz) and women (IA: 4.23 ± 0.18 Hz, TP: 4.34 ± 0.18 Hz, MS: 4.28 ± 0.17 Hz). The data analysis indicates that step characteristics interact differently in men and women across phases. Men do not take full advantage of their higher explosive strength to develop step length and speed during IA, because normalized step length differed only slightly (-4.09%) between men (1.70 ± 0.21) and women (1.66 ± 0.13). However, men outscored women clearly in acceleration (+34.5%) during the TP because they were capable of developing higher step lengths (2.04 ± 0.12 m in men vs. 1.85 ± 0.07 m in women), even when normalized for leg length (2.65 ± 0.12 in men vs. 2.47 ± 0.22 in women). At MS, it was concluded that men and women pursue an optimal balance between step rate and step length because a high negative correlation was found in both sexes (r = -0.94 and r = -0.77). Therefore, training approach needs to be customized to gender-related differences in step length-rate interaction.

  19. Achievement of peak VO2 during a 90-s maximal intensity cycle sprint in adolescents.

    PubMed

    Williams, Craig A; Ratel, Sébastien; Armstrong, Neil

    2005-04-01

    The aim of this study was to determine whether peak oxygen uptake (PVO2) attained in a 90-s maximal intensity cycle sprint is comparable to that from a conventional ramp test. Sixteen participants (13 boys and 3 girls, 14.6 +/- 0.4 yr) volunteered for the study. On Day 1 they completed a PVO2 test to exhaustion using a 25 W x min(-1) ramp protocol beginning at 50 W. Peak VO2 was defined as the highest VO2 value achieved, and aerobic power (Wmax) as the power output of the final 30 s. On Day 2 the participants completed two 90-s maximal sprints (S1 and S2). A 45-min recovery period separated each sprint. Mean oxygen uptake over the last 10 s of each sprint was determined as PVO2, and minimum power (MinP-30 s) as the mechanical power attained in the final 30 s. A one-way ANOVA was used to analyse differences between S1, S2, and the ramp test for PVO2 and MinP-30 s. Peak VO2 was not significantly different between the ramp, S1, or S2 (2.64 +/- 0.5, 2.49 +/- 0.5, and 2.53 +/- 0.5 L x min(-1), respectively, p > 0.68). The S1 and S2 PVO2 scores represented 91 +/- 10% and 92 +/- 10% of the ramp aerobic test. The MinP-30 s for S1 and S2 were significantly lower than the Wmax of the ramp test, p < 0.05. Hence, for researchers solely interested in PVO2 values, a shorter but more intensive protocol provides an alternative method to the traditional ramp aerobic test. PMID:15981785

  20. Influences of coaches, parents, and peers on the motivational patterns of child and adolescent athletes.

    PubMed

    Chan, D K; Lonsdale, C; Fung, H H

    2012-08-01

    The purposes of this study were to assess the relative impact of social influences initiated by coach, parents, and peers on children and adolescent athletes' motivational patterns, involving self-rated effort, enjoyment, competence, and competitive trait anxiety. Questionnaire data were collected from 408 youth swimmers (aged 9-18 years). Results of multi-group structural equation modeling analyses generally showed that compared with athletes in the other age group, the social influence from mother was stronger in childhood (mean age=10.87 years; SD=1.00), and that from peers was greater in adolescence (mean age=16.32 years; SD=1.15). The social influence from coach was more influential for athletes' effort and enjoyment in childhood, and competence in adolescence. We concluded that age appeared to moderate the impact of social influence from significant others on young athletes' sport experiences.

  1. Effect of Different Sprint Training Methods on Sprint Performance Over Various Distances: A Brief Review.

    PubMed

    Rumpf, Michael C; Lockie, Robert G; Cronin, John B; Jalilvand, Farzad

    2016-06-01

    Rumpf, MC, Lockie, RG, Cronin, JB, and Jalilvand, F. Effect of different sprint training methods on sprint performance over various distances: a brief review. J Strength Cond Res 30(6): 1767-1785, 2016-Linear sprinting speed is an essential physical quality for many athletes. There are a number of different training modalities that can be used to improve sprint performance. Strength and conditioning coaches must select the most appropriate modalities for their athletes, taking into consideration the sprint distances that typically occur during competition. The study purpose was to perform a brief review as to the effect of specific (free sprinting; resisted sprinting by sleds, bands, or incline running; assisted sprinting with a towing device or a downhill slope), nonspecific (resistance and plyometric training), and combined (a combination of specific and nonspecific) training methods on different sprint distances (0-10, 0-20, 0-30, and 31+ m). A total of 48 studies fulfilled the inclusion criteria, resulting in 1,485 subjects from a range of athletic backgrounds. The training effects associated with specific sprint training were classified as moderate (effect size [ES] = -1.00; %change = -3.23). Generally, the effect of specific sprint training tended to decrease with distance, although the largest training effects were observed for the 31+ m distance. The greatest training effects (ES = -0.43; %change = -1.65) of nonspecific training were observed for the 31+ m distance. The combined training revealed greatest effects (ES = -0.59; %change = -2.81) for the 0-10 m distance. After this review, specific sprint training methods seem the most beneficial over the investigated distances. However, the implementation of nonspecific training methods (e.g., strength and power training) could also benefit speed and athletic performance.

  2. Functional anatomy and muscle moment arms of the thoracic limb of an elite sprinting athlete: the racing greyhound (Canis familiaris)

    PubMed Central

    Williams, S B; Wilson, A M; Daynes, J; Peckham, K; Payne, R C

    2008-01-01

    We provide quantitative muscle–tendon architecture and geometry data for the racing greyhound thoracic limb. Muscle mass, belly length, fascicle lengths, pennation angles and moment arms were measured, as were tendon masses and lengths. Maximum isometric force and maximum power were estimated for muscles, and maximum stress and strain were estimated for tendons. Results are compared with other fast quadrupedal runners, and to previously published data in mixed-breed dogs. The implications of the functional adaptations of the greyhound thoracic limb for sprinting performance are discussed. The thoracic limb was found to benefit from a similar proportion of locomotor muscle mass to the pelvic limb, suggesting that it may be used to some extent in propulsion, or alternatively that stabilisation is very important in this animal. Extrinsic muscles, especially latissimus dorsi and pectoralis profundus, were predicted to be powerful and important for generating net positive work during accelerations. Proximal biarticular muscles show specialisation toward preventing collapse of the shoulder and elbow joints to enable strut-like limb function, or some form of dynamic control. Distal muscles did not appear specialised for elastic energy storage, a functional difference to pelvic limb muscles, and the equivalents in horse thoracic limbs. The greyhound thoracic limb appears to possess substantial differences from both that of more ‘sub-maximal specialist’ quadrupeds, and from the greyhound pelvic limb. PMID:19034998

  3. The effects of rear-wheel camber on the mechanical parameters produced during the wheelchair sprinting of handibasketball athletes.

    PubMed

    Faupin, Arnaud; Campillo, Philippe; Weissland, Thierry; Gorce, Philippe; Thevenon, André

    2004-05-01

    The wheel camber of a wheelchair is a significant parameter that must be taken into account in the search for optimal regulation of a wheelchair. This study examined the effects of different rear-wheel camber (9 degrees , 12 degrees and 15 degrees )-today used mainly in the handibasket championship-on the various kinetic and kinematic parameters of the propulsion cycle. Eight males, all players in the French handibasket championship, were asked to participate in this study. They performed three 8 s maximal sprints as measured by a wheelchair ergometer, 9 degrees , 12 degrees , and 15 degrees of rear-wheel camber. The results of our study show that residual torque increases in proportion to the increase in wheel camber. This could explain other study results, which show a decrease in mean velocity and an increase in both power output and time of the propelling phase, in relation to the wheel camber. These results should provide the information necessary for optimal wheelchair regulation.

  4. Impact of maximum speed on sprint performance during high-level youth female field hockey matches: female athletes in motion (FAiM) study.

    PubMed

    Vescovi, Jason D

    2014-07-01

    The aim of this study was to examine the impact of maximum sprint speed on peak and mean sprint speed during youth female field hockey matches. Two high-level female field hockey teams (U-17, n = 24, and U-21, n = 20) were monitored during a 4-game international test series using global position system technology and tested for maximum sprint speed. Dependent variables were compared using a 3-factor ANOVA (age group, position, and speed classification); effect sizes (Cohen d) and confidence limits were also calculated. Maximum sprint speed was similar between age groups and positions, with faster players having greater speed than slower players (29.3 ± 0.4 vs 27.2 ± 1.1 km/h). Overall, peak match speed in youth female field hockey players reaches approximately 90% of maximum sprint speed. Absolute peak match speed and mean sprint speed during matches were similar among the age groups (except match 1) and positions (except match 2); however, peak match speed was greater for faster players in matches 3 and 4. No differences were observed in the relative proportion for mean sprint speeds for age groups or positions, but slower players consistently displayed similar relative mean sprint speeds by using a greater proportion of their maximum sprint speed.

  5. Influence of ghrelin and adipocytokines on bone mineral density in adolescent female athletes with amenorrhea and eumenorrheic athletes.

    PubMed

    Russell, Melissa; Misra, Madhusmita

    2010-01-01

    Adolescent female athletes are at increased risk for low bone mineral density (BMD) secondary to exercise-induced hypogonadism. Of particular concern is that the adolescent years are also a critical time for bone accrual, and deficits incurred during this period could lead to suboptimal peak bone mass acquisition and subsequent fracture risk in later life. Although weight-bearing exercise is typically associated with an increase in BMD, amenorrheic athletes have lower BMD than eumenorrheic athletes and nonathletic controls as a consequence of low energy availability and subsequent hypogonadism. It is important to recognize that critical interactions exist between net energy availability and the hypothalamo-pituitary-gonadal (H-P-G) axis that are key to the development of a hypogonadal state when energy intake cannot keep pace with expenditure. While the link between energy availability and gonadtotropin pulsatility patterns is well established, the actual metabolic signals that link the two are less clear. Decreased energy availability in athletes is associated with decreases in fat mass, and alterations in adipokines (such as leptin and adiponectin) and fat-regulated hormones (such as ghrelin and peptide YY). These hormones impact the H-P-G axis in animal models, and it is possible that in athletes alterations in fat-related hormones signal the state of energy availability to the hypothalamus and contribute to suppression of gonadotropin pulsatility, hypothalamic amenorrhea and consequent decreased BMD. A better understanding of pathways linking low energy availability with functional hypothalamic amenorrhea and low BMD is critical for the development of future therapeutic strategies addressing these issues in amenorrheic athletes. PMID:20956863

  6. The relationships among bone health, insulin-like growth factor-1 and sex hormones in adolescent female athletes.

    PubMed

    Gruodyte, Rita; Jürimäe, Jaak; Saar, Meeli; Jürimäe, Toivo

    2010-05-01

    The aim of this study was to determine the relationships of bone mineral density (BMD) and content (BMC) with insulin-like growth factor-1 (IGF-1), IGF-binding protein-3 (IGFBP-3) and estradiol in pubertal female athletes. The participants were 170 healthy adolescent girls (13-15 years) who participated in competitive extramural athletic programs, i.e., sports games (n = 49), track sprinting (n = 24), rhythmic gymnastics (n = 23), swimming (n = 24) and cross-country skiing (n = 17). The control group (n = 33) consisted of girls who took part only in compulsory physical education classes at school. The whole-body BMD and femoral neck and lumbar spine BMD and BMC were measured using DXA, and the volumetric BMD was calculated. Venous blood samples to determine the concentration of IGF-1, IGFBP-3 and estradiol were drawn after an overnight fasting. After adjusting for age, body height and body mass, the relationships among BMD variables, IGF-1 and the IGF-1/IGFBP-3 molar ratio remained significant only in the rhythmic gymnast group. BMDs at the femoral neck and lumbar spine were also related to estradiol levels (r = 0.45-0.60; p < 0.05) only in the rhythmic gymnast group. No relationships were found among the measured BMD, IGF axis and estradiol in other athletic groups. Only BMC at the femoral neck remained associated with the IGF-1/IGFBP-3 molar ratio in the rhythmic gymnast group after adjusting for age, body height and body mass. Stepwise multiple regression analysis indicated that IGF-1 and estradiol together explained 42.6% (R(2) x 100) of total variance in the femoral neck BMD and IGF-1 alone 35.4% (R(2) x 100) of the total variance in the femoral neck BMC only in the rhythmic gymnast group. We conclude that femoral neck and lumbar spine BMD correlated with IGF-1, IGF-1/IGFBP-3 molar ratio and estradiol in rhythmic gymnasts. No relationships were found between bone parameters and the hormones used in other athletic groups.

  7. Oral trauma in adolescent athletes: a study of mouth protectors.

    PubMed

    McNutt, T; Shannon, S W; Wright, J T; Feinstein, R A

    1989-09-01

    The purpose of this study was to determine the extent of mouth protector use, as well as the amount and type of oral trauma associated with and without mouth guard wear in adolescent athletes. Coaches' perceptions and regulations involving the use of mouth protectors also were examined. Interviews were collected from 2470 junior and senior high school football players with all oral trauma being documented, regardless of the sport during which the injury occurred. Nine per cent of all players suffered from some form of oral injury while another 3% reported a loss of consciousness. Seventy-five per cent of the injuries occurred while not wearing mouth guards, and of this total 40% occurred during baseball and basketball. Fifty-six per cent of all concussions were suffered while not wearing mouth guards. Despite the ability of mouth protectors to significantly help reduce oral injuries, trauma related to sports is more prevalent than previously reported. This study supports the recommendation of mandatory mouth guards in baseball and basketball.

  8. Prediction of sport adherence through the influence of autonomy-supportive coaching among spanish adolescent athletes.

    PubMed

    Almagro, Bartolomé J; Sáenz-López, Pedro; Moreno, Juan A

    2010-01-01

    The purpose of this study was to test a motivational model of the coach-athlete relationship, based on self-determination theory and on the hierarchical model of intrinsic and extrinsic motivation. The sample comprised of 608 athletes (ages of 12-17 years) completed the following measures: interest in athlete's input, praise for autonomous behavior, perceived autonomy, intrinsic motivation, and the intention to be physically active. Structural equation modeling results demonstrated that interest in athletes' input and praise for autonomous behavior predicted perceived autonomy, and perceived autonomy positively predicted intrinsic motivation. Finally, intrinsic motivation predicted the intention to be physically active in the future. The results are discussed in relation to the importance of the climate of autonomy support created by the coach on intrinsic motivation and adherence to sport by adolescent athletes. Further, the results provide information related to the possible objectives of future interventions for the education of coaches, with the goal of providing them with tools and strategies to favor the development of intrinsic motivation among their athletes. In conclusion, the climate of autonomy support created by the coach can predict the autonomy perceived by the athletes which predicts the intrinsic motivation experienced by the athletes, and therefore, their adherence to athletic practice. Key pointsImportance of the climate of autonomy support created by the coach on intrinsic motivation and adherence to sport by adolescent athletes.Interest in athletes' input and praise for autonomous behavior predicted perceived autonomy, and perceived autonomy positively predicted intrinsic motivation.Intrinsic motivation predicted the intention to be physically active in the future. PMID:24149380

  9. Prediction of Sport Adherence Through the Influence of Autonomy-Supportive Coaching Among Spanish Adolescent Athletes

    PubMed Central

    Almagro, Bartolomé J.; Sáenz-López, Pedro; Moreno, Juan A.

    2010-01-01

    The purpose of this study was to test a motivational model of the coach-athlete relationship, based on self-determination theory and on the hierarchical model of intrinsic and extrinsic motivation. The sample comprised of 608 athletes (ages of 12-17 years) completed the following measures: interest in athlete's input, praise for autonomous behavior, perceived autonomy, intrinsic motivation, and the intention to be physically active. Structural equation modeling results demonstrated that interest in athletes' input and praise for autonomous behavior predicted perceived autonomy, and perceived autonomy positively predicted intrinsic motivation. Finally, intrinsic motivation predicted the intention to be physically active in the future. The results are discussed in relation to the importance of the climate of autonomy support created by the coach on intrinsic motivation and adherence to sport by adolescent athletes. Further, the results provide information related to the possible objectives of future interventions for the education of coaches, with the goal of providing them with tools and strategies to favor the development of intrinsic motivation among their athletes. In conclusion, the climate of autonomy support created by the coach can predict the autonomy perceived by the athletes which predicts the intrinsic motivation experienced by the athletes, and therefore, their adherence to athletic practice. Key points Importance of the climate of autonomy support created by the coach on intrinsic motivation and adherence to sport by adolescent athletes. Interest in athletes' input and praise for autonomous behavior predicted perceived autonomy, and perceived autonomy positively predicted intrinsic motivation. Intrinsic motivation predicted the intention to be physically active in the future. PMID:24149380

  10. An Examination of the Dual Model of Perfectionism and Adolescent Athlete Burnout: A Short-Term Longitudinal Research

    ERIC Educational Resources Information Center

    Chen, Lung Hung; Kee, Ying Hwa; Tsai, Ying-Mei

    2009-01-01

    The dual model of perfectionism (Slade and Owens, Behav Modificat 22(3):372-390, 1998) is adopted to examine the influence of adaptive and maladaptive perfectionism on adolescent athlete burnout in Taiwan. Participants were 188 high school adolescent student-athletes (M = 16.48, SD = 0.59). They were administered the Multidimensional Inventory of…

  11. HIGH SCHOOL ATHLETIC PARTICIPATION AND ADOLESCENT SUICIDE: A Nationwide US Study.

    PubMed

    Sabo, Don; Miller, Kathleen E; Melnick, Merrill J; Farrell, Michael P; Barnes, Grace M

    2005-01-01

    Suicide is the third leading cause of death among US adolescents aged 15-24, with males incurring higher rates of completion than females. This study used hierarchical logistic regression analysis to test whether athletic participation was associated with lower rates of suicidal ideation and behavior among a nationally representative sample of over 16,000 US public and private high school students. Net of the effects of age, race/ethnicity, parental educational attainment, and urbanicity, high school athletic participation was significantly associated with reduced odds of considering suicide among both females and males, and reduced odds of planning a suicide attempt among females only. Though the results point to favorable health outcomes for athletes, athletic participation was also associated with higher rates of injury to male athletes who actually attempted suicide. PMID:18846245

  12. Sprint interval training (SIT) is an effective method to maintain cardiorespiratory fitness (CRF) and glucose homeostasis in Scottish adolescents

    PubMed Central

    Martin, R; Baker, JS; Young, J; Sculthorpe, N; Grace, FM

    2015-01-01

    The present study examined the physiological impact of a school based sprint interval training (SIT) intervention in replacement of standard physical education (SPE) class on cardio-respiratory fitness (CRF) and glucose homeostasis during the semester following summer vacation. Participants (n=49) were randomly allocated to either intervention (SIT; n=26, aged 16.9 ± 0.3 yrs) or control group who underwent standard physical education (SPE; n=23, aged 16.8 ± 0.6 yrs). CRF (VO2max) and glucose homeostasis were obtained prior-to and following 7 weeks of SIT exercise. Significant group x time interaction was observed for CRF (P < 0.01) with non-significant trends for fasting insulin (P= 0.08), and HOMA-IR (P=0.06). CRF decreased (P < 0.01) in SPE such that POST intervention CRF was significantly lower (P< 0.05) in SPE. Fasting plasma glucose (P < 0.01), insulin (P< 0.01) and HOMA-IR (P< 0.01) increased significantly amongst SPE. The main finding of the present study is that 7-weeks of SIT exercise is an effective method of maintaining (but not improving) CRF and fasting insulin homeostasis amongst school-going adolescents. SIT exercise demonstrates potential as a time efficient physiological adjunct to standard PE class in order to maintain CRF during the school term. PMID:26681833

  13. Effects of three types of resisted sprint training devices on the kinematics of sprinting at maximum velocity.

    PubMed

    Alcaraz, Pedro E; Palao, José M; Elvira, José L L; Linthorne, Nicholas P

    2008-05-01

    Resisted sprint running is a common training method for improving sprint-specific strength. For maximum specificity of training, the athlete's movement patterns during the training exercise should closely resemble those used when performing the sport. The purpose of this study was to compare the kinematics of sprinting at maximum velocity to the kinematics of sprinting when using three of types of resisted sprint training devices (sled, parachute, and weight belt). Eleven men and 7 women participated in the study. Flying sprints greater than 30 m were recorded by video and digitized with the use of biomechanical analysis software. The test conditions were compared using a 2-way analysis of variance with a post-hoc Tukey test of honestly significant differences. We found that the 3 types of resisted sprint training devices are appropriate devices for training the maximum velocity phase in sprinting. These devices exerted a substantial overload on the athlete, as indicated by reductions in stride length and running velocity, but induced only minor changes in the athlete's running technique. When training with resisted sprint training devices, the coach should use a high resistance so that the athlete experiences a large training stimulus, but not so high that the device induces substantial changes in sprinting technique. We recommend using a video overlay system to visually compare the movement patterns of the athlete in unloaded sprinting to sprinting with the training device. In particular, the coach should look for changes in the athlete's forward lean and changes in the angles of the support leg during the ground contact phase of the stride.

  14. Eating Disorders among Adolescent Female Athletes: Influence of Athletic Participation and Sport Team Membership.

    ERIC Educational Resources Information Center

    Taub, Diane E.; Blinde, Elaine M.

    1992-01-01

    Comparison of high school female athletes (n=100) and nonathletes (N=112) revealed that athletes were more likely than nonathletes to possess certain behavioral and psychological correlates of eating disorders. There were few differences among various sport teams. Gender-role orientation was generally not critically variable. (Author/NB)

  15. A Unique Patient Population? Health-Related Quality of Life in Adolescent Athletes Versus General, Healthy Adolescent Individuals

    PubMed Central

    Lam, Kenneth C.; Valier, Alison R. Snyder; Bay, R. Curtis; McLeod, Tamara C. Valovich

    2013-01-01

    Context: Normative scores for patient-rated outcome (PRO) instruments are important for providing patient-centered, whole-person care and making informed clinical decisions. Although normative values for the Pediatric Quality of Life Generic Core Scale (PedsQL) have been established in the general, healthy adolescent population, whether adolescent athletes demonstrate similar values is unclear. Objective: To compare PedsQL scores between adolescent athletes and general, healthy adolescent individuals. Design: Cross-sectional study. Setting: Secondary schools. Patients or Other Participants: A convenience sample of 2659 interscholastic athletes (males = 2059, females = 600, age = 15.7 ± 1.1 years) represented the athlete group (ATH), and a previously published normative dataset represented the general, healthy adolescent group (GEN). Intervention(s): All participants completed the PedsQL during 1 testing session. Main Outcome Measure(s): The PedsQL consists of 2 summary scores (total, psychosocial) and 4 subscale scores (physical, emotional, social, school), with higher scores indicating better health-related quality of life (HRQOL). Groups were stratified by age (14, 15, or 16 years old). Independent-samples t tests were conducted to compare between-groups and sex differences. Results: The ATH group scored higher than the GEN group across all ages for total and psychosocial summary scores and for emotional and social functioning subscale scores (P ≤ .005). For physical functioning, scores of the 15-year-old ATH were higher than for their GEN counterparts (P = .001). Both 14- and 15-year-old ATH scored higher than their GEN counterparts for the school functioning subscale (P ≤ .013), but differences between 16-year olds were not significant (P = .228). Male adolescent athletes reported higher scores than female adolescent athletes across all scores (P ≤ .001) except for social functioning (P = .229). Conclusions: Adolescent athletes reported better HRQOL than

  16. Physical self-concept and disturbed eating attitudes and behaviors in French athlete and non-athlete adolescent girls: direct and indirect relations.

    PubMed

    Monthuy-Blanc, Johana; Maïano, Christophe; Morin, Alexandre J S; Stephan, Yannick

    2012-06-01

    This study aims to investigate the direct and indirect associations between physical self-subdomains, physical self-worth, global self-worth, and disturbed eating attitudes and behaviors among French non-elite athlete and non-athlete adolescent girls. A sample of adolescent girls including 50 ballet dancers, 41 basketball players, and 47 non-athletes was used in this study. Data obtained from the ballet dancer and basketball player subsamples revealed significant, sample-specific as well as common, direct relations between global and physical self-perceptions and disturbed eating attitudes and behaviors, as well as significant indirect relations (via global self-worth and physical self-worth) between specific physical self-perceptions and disturbed eating attitudes and behaviors. In contrast, no association was found between global and physical self-perceptions in the sample of non-athlete adolescent girls.

  17. The influence of upper-body strength on flat-water sprint kayak performance in elite athletes.

    PubMed

    McKean, Mark R; Burkett, Brendan J

    2014-07-01

    Dry-land strength training is a fundamental component for elite kayak performance. The aims of this research were 3-fold: 1st, to determine the relationship between performance time and strength scores for elite kayakers; 2nd, to identify how strength changes (gains or losses) over 3 training y relate with changes in performance time for elite kayakers; and 3rd, to compare the progression in performance times for elite athletes with the top 3 performers from the national championships. The performance data for 15 elite male and 10 elite female kayakers were collected over 2 y. This group was reduced to 9 men and 8 women in the 3rd and final year. There were direct and significant correlations between strength scores and performance times across the 3 y. Bench-press 1RM increased by 34.8% for men and 42.3% for women. Over the 3 seasons, mean 1000-m time decreased by approximately 4.8%, 500-m times decreased by 7.3% (women), and 200-m times decreased by 9.1%. The women's 500-m changed from 11.9% difference from medalists to within 1.1% during the 3 y. During the 3 y of this study a change in 1-repetitionmaximum (1RM) bench press of 13% for men and 6.5% in women coincided with a change in performance times of 1%. For 1RM pull-up a change of 10% in men and 2.3% in women coincided with a change in performance times of 1%.

  18. Evidence of imbalanced adaptation between muscle and tendon in adolescent athletes.

    PubMed

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

    2014-08-01

    Adolescence may be regarded as a critical phase of tissue plasticity in young growing athletes, as the adaptation process of muscle-tendon unit is affected by both environmental mechanical stimuli and maturation. The present study investigated potential imbalances of knee extensor muscle strength and patellar tendon properties in adolescent compared with middle-aged athletes featuring long-term musculotendinous adaptations. Nineteen adolescent elite volleyball athletes [(A), 15.9 ± 0.6 years] and 18 middle-aged competitively active former elite volleyball athletes [(MA), 46.9 ± 0.6 years] participated in magnetic resonance imaging and ultrasound-dynamometry sessions to determine quadriceps femoris muscle strength, vastus lateralis morphology and patellar tendon mechanical and morphological properties. There was no significant age effect on the physiological cross-sectional area of the vastus lateralis and maximum knee extension moment (P > 0.05) during voluntary isometric contractions. However, the patellar tendon cross-sectional area was significantly smaller (A: 107.4 ± 27.5 mm(2) ; MA: 121.7 ± 39.8 mm(2) ) and the tendon stress during the maximal contractions was significantly higher in adolescent compared with the middle-aged athletes (A: 50.0 ± 10.1 MPa; MA: 40.0 ± 9.5 MPa). These findings provide evidence of an imbalanced development of muscle strength and tendon mechanical and morphological properties in adolescent athletes, which may have implications for the risk of tendon overuse injuries.

  19. Influence of Strength, Sprint Running, and Combined Strength and Sprint Running Training on Short Sprint Performance in Young Adults.

    PubMed

    Marques, M C; Gabbett, T J; Marinho, D A; Blazevich, A J; Sousa, A; van den Tillaar, R; Izquierdo, M

    2015-10-01

    The purpose of this study was to assess the degree of transference of 6 weeks of full squat vs. full squat plus sprint running training to short (ranged from 0-10 to 0-30 m) sprint running performance in non-athletes. We hypothesized that a speed-full-squat training regimen could enhance squat strength and power with simultaneous improvements in short sprint performance. 122 physically active adults (age: 20.5±2.5 years; body mass: 65.8±6.1 kg; height: 1.71±0.08 m) were randomly divided into 4 groups: full squat training (n=36), combined full squat and sprint training (n=32), speed training only (n=34) and non-training control group (n=20). Each training group completed 2 sessions per week over 6 weeks, while the control group performed only their normal physical activity. Sprint performance was improved after sprint running or full squat training alone (1.7% and 1.8% P<0.05, respectively), however larger enhancements (2.3%; P<0.01) were observed after the combined full squat plus sprint training intervention. These results suggest that in recreationally active adults, combined full squat and sprint training provides a greater stimulus for improving sprint performance than either modality alone.

  20. 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…

  1. Adolescent Siblings' Daily Discussions: Connections to Perceived Academic, Athletic, and Peer Competency

    ERIC Educational Resources Information Center

    Tucker, Corinna Jenkins; Winzeler, Abby

    2007-01-01

    First- and second-born adolescent siblings from 21 families completed a daily diary on each of 7 days. The frequency and content of siblings' conversations are described and the relationship between the content of siblings' discussion and their perceived academic, athletic, and peer competency is explored. Siblings most often talked about…

  2. Sports and Athletics: Issues for Adolescents with Chronic Illnesses and Disabilities. CYDLINE Reviews.

    ERIC Educational Resources Information Center

    Minnesota Univ., Minneapolis. National Center for Youth with Disabilities.

    This annotated bibliography focuses on issues in sports and athletics for adolescents and young adults with chronic illnesses and disabilities. The listings are drawn from the National Resource Library of the National Center for Youth with Disabilities, which includes journals, books, and non-published materials. The section on bibliographic…

  3. Hormonal response to Taekwondo fighting simulation in elite adolescent athletes.

    PubMed

    Pilz-Burstein, R; Ashkenazi, Y; Yaakobovitz, Y; Cohen, Y; Zigel, L; Nemet, D; Shamash, N; Eliakim, A

    2010-12-01

    Exercise training efficiency depends on the training load, as well as on the athlete's ability to tolerate it. The aim of the present study was to evaluate the effect of fighting simulation (3 fights, 6 min each, 30 min rest between fights) on anabolic (IGF-I, LH, FSH, estradiol, and testosterone) and catabolic hormones (cortisol) in elite, male (n = 10) and female (n = 10) adolescent (12-17 years) Taekwondo fighters. Blood samples were collected before the first and immediately after the third fight. The fighting simulation practice led to significant (p < 0.05) decreases in IGF-I (males -27.1 ± 25.6, females -22.4 ± 36.3 ng/ml), LH (males -0.7 ± 1.2, females -2.3 ± 3.3 U/L), and FSH (males -0.9 ± 0.5, females -1.5 ± 1.1 U/L), and to a significant increase (p < 0.05) in cortisol (males 141.9 ± 30.1, females 64.1 ± 30.6 mcg/dL) in both genders. Fighting simulation decreases in testosterone (males -1.9 ± 1.6, females -0.02 ± 0.06 ng/mL), and free androgen index (males -20.1 ± 21.5, females -0.3 ± 0.5) were significant (p < 0.05) only in male fighters. Exercise had no significant effect on estradiol, sex-hormone-binding globulins or thyroid function tests. Our data demonstrate that the physiologic and psychologic strain of a Taekwondo fighting simulation day led to a catabolic-type circulating hormonal response. PMID:20803154

  4. Overuse Injuries of the Pediatric and Adolescent Throwing Athlete.

    PubMed

    Tisano, Breann K; Estes, A Reed

    2016-10-01

    In the hypercompetitive environment of year round youth baseball, arm pain is commonplace. Although much research has been done about injuries in the overhead throwing athlete, the emphasis has been on the more elite levels, where athletes have reached full development. The anatomy of the skeletally immature athlete, including open physeal plates and increased tissue laxity, raises unique issues in the presentation and treatment of repetitive throwing injuries of the elbow and shoulder. With a focus on "little leaguers," this discussion evaluates five of the most common elbow and shoulder injuries-Little Leaguer's elbow, ulnar collateral ligament sprain or tear, osteochondritis dissecans/Panner's disease, Little Leaguer's shoulder, and multidirectional instability. In the developmentally distinct pediatric athlete, pathogenesis, diagnosis, and treatment may differ from that established for adults. Offering early diagnosis and treatment appropriate to a child's level of development will enable youth to not only continue to play sports but to also maintain full functionality as active adults.

  5. Overuse Injuries of the Pediatric and Adolescent Throwing Athlete.

    PubMed

    Tisano, Breann K; Estes, A Reed

    2016-10-01

    In the hypercompetitive environment of year round youth baseball, arm pain is commonplace. Although much research has been done about injuries in the overhead throwing athlete, the emphasis has been on the more elite levels, where athletes have reached full development. The anatomy of the skeletally immature athlete, including open physeal plates and increased tissue laxity, raises unique issues in the presentation and treatment of repetitive throwing injuries of the elbow and shoulder. With a focus on "little leaguers," this discussion evaluates five of the most common elbow and shoulder injuries-Little Leaguer's elbow, ulnar collateral ligament sprain or tear, osteochondritis dissecans/Panner's disease, Little Leaguer's shoulder, and multidirectional instability. In the developmentally distinct pediatric athlete, pathogenesis, diagnosis, and treatment may differ from that established for adults. Offering early diagnosis and treatment appropriate to a child's level of development will enable youth to not only continue to play sports but to also maintain full functionality as active adults. PMID:27254261

  6. Sex Objects, Athletes, and Sexy Athletes: How Media Representations of Women Athletes Can Impact Adolescent Girls and College Women

    ERIC Educational Resources Information Center

    Daniels, Elizabeth A.

    2009-01-01

    In contrast to the large body of research examining the negative effects of idealized media images on girls' and women's body image, little research has investigated whether media images can positively impact body concept among females. Using a between-participants experimental design, this study examined how images of performance athletes,…

  7. Female adolescent athletes' coping: a season-long investigation.

    PubMed

    Tamminen, Katherine A; Holt, Nicholas L

    2010-01-01

    Athletes' stressors and coping have been studied over relatively short periods or time (i.e. 28 or 31 days; Nicholls, 2007), but little is known about how stressors and coping fluctuate over the course of an entire competitive season. The first objective of this study was to examine recurrent stressors and coping strategies over the course of the season. The second objective was to examine coping as a process. Thirteen female basketball players (mean age 16 years) completed pre- and post-season interviews and maintained audio diaries during the season. Content analyses were completed and themes were analysed longitudinally across three phases of the season (early, mid, and late). Reported stressors changed across phases of the season, and these changes appeared to relate to the team's changing contextual demands. Coping strategies also changed across phases of the season. Individual profiles of each athlete's coping over the season were created. Ten athletes were generally more reactive in their coping, while only three athletes were more proactive. The three athletes identified with a proactive approach planned their coping and used feedback to evaluate coping efforts. Planning and evaluation appeared to distinguish between more reactive and more proactive coping.

  8. Athletic competition: a means of improving the self-image of the mentally retarded adolescent?

    PubMed

    Ninot, G; Bilard, J; Sokolowski, M

    2000-06-01

    This study investigated whether participation in athletic training and competition positively affects self-perception in the different domains of competence in mentally retarded adolescents. We compared the effects of sport participation in four groups of eight mentally retarded adolescents over a period of 14 months. The adolescents were all students in specialized learning centres. The four athletic groups were constituted as follows: segregated basketball practice and meets, integrated basketball practice and meets, segregated swimming practice and meets, integrated swimming practice and meets. Two other groups served as controls: a sedentary group and a group that participated in classic adapted physical activities. We used skill tests and Harter's Self-Perception Profile for Children (1985) to measure, respectively, athletic skill and domains of perceived competence. The results showed that athletic skill increased over the 14 months, but the perception of competence in the subjects who participated in the segregated meets did not increase significantly in perceived physical ability, or in any other domain. Moreover, the integrated basketball group showed a decrease in perceived physical ability. The results are discussed in terms of the influence of specialized classes.

  9. The female athletic role as a status determinant within the social systems of high school adolescents.

    PubMed

    Kane, M J

    1988-01-01

    This study examined the relationship between female athletic participation and status attainment within the social status systems of high school adolescents. Although earlier research has consistently demonstrated that the athletic role for males is associated with greatest status within the school, findings regarding the status of female athletes have been contradictory: Some studies have found high status rankings for female athletes while others have revealed negative results. It was therefore argued that current research go beyond the general construct of "female athlete" and consider the type of sport with which the adolescent female is associated as a possible status determinant. Employing a sport typology proposed by Metheny (1967), it was predicted that females associated with sex-appropriate or "feminine" sports (e.g., tennis) would receive significantly higher status ratings than those identified with sex-inappropriate or "masculine" sports (e.g., basketball). One hundred and twenty-one male subjects were asked to indicate which female athlete (associated with a sex-appropriate versus a sex-inappropriate sport) they would most like to date, while 111 female subjects were asked to choose which female athlete they would most like to have as a friend. Chi-square analyses revealed that, as predicted, females associated with sex-appropriate sports were given significantly greater status than females identified with sex-inappropriate sports by both male and female subjects. These results suggest that social assessments made about female sport participation within high school status systems remain heavily influenced by traditional beliefs regarding feminine, "ladylike" behavior.

  10. [Lumbar spine injuries in pediatric and adolescent athletes].

    PubMed

    Berk, R Haluk

    2004-01-01

    During the past two decades, there has been a significant increase in sports participation by pediatric athletes. Spinal injuries thus have become a great concern. The unique nature of the pediatric spine should be well-recognized and low back pain in a pediatric athlete should therefore be taken seriously and evaluated thoroughly. In this review article, sports-related lumbar spine problems will be covered including overuse injuries, spondylolysis, pars stress fractures, spondylolysthesis, and lumbar disc herniation. Early identification of these problems will eventually minimize these injuries. PMID:15187460

  11. Solar Sprint

    ERIC Educational Resources Information Center

    Tabor, Richard; Anderson, Stephen

    2007-01-01

    In the "Solar Sprint" activity, students design, test, and race a solar-powered car built with Legos. The use of ratios is incorporated to simulate the actual work of scientists and engineers. This method encourages fourth-grade students to think about multiple variables and stimulates their curiosity when an activity doesn't come out as…

  12. Exercise Fatigue in Adolescents: Diagnosis of Athlete Burnout.

    ERIC Educational Resources Information Center

    Rowland, Thomas W.

    1986-01-01

    Chronic fatigue, declining performance, and mental lassitude, all symptoms of athlete burnout syndrome, require a comprehensive diagnostic approach. Many factors which can interfere with normal exercise capacity are easily treatable so a careful search is important. Three case studies are presented. (Author/MT)

  13. Contributions of athletic identity to child and adolescent physical activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identity theorists maintain that domain-specific self-concepts help explain the differential investment of people's time and effort in various activities. This study examined the contribution of athletic identity and three key demographic variables to physical activity and sports team participation...

  14. Additional Post-Concussion Impact Exposure May Affect Recovery in Adolescent Athletes.

    PubMed

    Terwilliger, Virginia K; Pratson, Lincoln; Vaughan, Christopher G; Gioia, Gerard A

    2016-04-15

    Repeat concussion has been associated with risk for prolonged and pronounced clinical recovery in athletes. In this study of adolescent athletes, we examined whether an additional head impact within 24 h of a sports-related concussion (SRC) is associated with higher symptom burden and prolonged clinical recovery compared with a single-injury group. Forty-two student-athletes (52% male, mean age = 14.9 years) diagnosed with an SRC in a concussion clinic were selected for this study: (1) 21 athletes who sustained an additional significant head impact within 24 h of the initial injury (additional-impact group); (2) 21 single-injury athletes, age and gender matched, who sustained only one discrete concussive blow to the head (single-injury group). Groups did not differ on initial injury characteristics or pre-injury risk factors. The effect of injury status (single- vs. additional-impact) was examined on athlete- and parent-reported symptom burden (at first clinic visit) and length of recovery (LOR). Higher symptom burden was reported by the athletes and parents in the additional-impact group at the time of first visit. The additional-impact group also had a significantly longer LOR compared with the single-injury group. These findings provide preliminary, hypothesis-generating evidence for the importance of immediate removal from play following an SRC to protect athletes from re-injury, which may worsen symptoms and prolong recovery. The retrospective study design from a specialized clinical sample points to the need for future prospective studies of the relationship between single- and additional-impact injuries on symptom burden and LOR. PMID:26421452

  15. Incidence of exercise-induced asthma in adolescent athletes under different training and environmental conditions.

    PubMed

    Sidiropoulou, Maria P; Kokaridas, Dimitrios G; Giagazoglou, Paraskevi F; Karadonas, Michalis I; Fotiadou, Eleni G

    2012-06-01

    The aim of this study was to establish if there were differences in the incidence of exercise-induced bronchospasm between athletes in different sports, which take place under different environmental conditions such as open places, closed courses, and swimming pools with similar exercise intensity (football, basketball, water polo) using the free running test. The study included 90 adolescents (3 groups of 30) aged 14-18 years recruited from academies in northern Greece. All the participants were initially subjected to (a) a clinical examination and cardiorespiratory assessment by a physician and (b) free running test of a 6-minute duration and measurement with a microspirometer of the forced expiratory volume in 1 second (FEV₁). Only the participants who had measured a decrease in FEV₁ ≥ 10% were reevaluated with the microspirometer during a training session. The examination of all the participants during the free running test showed that 22 athletes, that is, 9, 8, and 5 of football, basketball, and water polo athletes, respectively, demonstrated an FEV₁ ≥ 10 drop. Reevaluation of the 22 participants during training showed that 5 out 9 (55%) football athletes, 4 out of 8 basketball athletes (50%), and none of the 5 athletes of the water polo team displayed a drop of FEV₁ ≥ 10%. Despite the absence of any significant statistical differences between the 3 groups, the analysis of variances did show a trend of a lower incidence of EIA in the water polo athletes. It was found that a football or basketball game can induce EIA in young athletes but to a lesser degree than the free running test can induce. The water polo can be a safer sport even for participants with a medical history of asthma or allergies.

  16. Grip strength is a predictor of bone mineral density among adolescent combat sport athletes.

    PubMed

    Nasri, Raouf; Hassen Zrour, Saoussen; Rebai, Haithem; Fadhel Najjar, Mohamed; Neffeti, Fadoua; Bergaoui, Naceur; Mejdoub, Hafedh; Tabka, Zouhair

    2013-01-01

    The aim of this study was firstly to investigate the correlation between bone parameters and grip strength (GS) in hands, explosive legs power (ELP), and hormonal parameters; second, to identify the most determinant variables of bone mineral density (BMD) among adolescent combat sport athletes. Fifty combat sport athletes aged 17.1 ± 0.2 year were compared with 30 sedentary subjects matched for age, height, and pubertal stage. For all subjects, the BMD in deferent sites associated with anthropometric parameters were measured by dual-energy X-ray absorptiometry. The growth hormone (GH) and testosterone (TESTO) concentrations were tested. The GS in dominant (GSDA) and nondominant arms (GSNDA) and ELP were evaluated. All BMD measured were greater in athletes than in sedentary group (p<0.01). The GS and ELP showed higher values in athletes than in sedentary group (p<0.01). The BMD in all sites were correlated with weight, but without correlation with height. The GSNDA and ELP were significantly correlated with BMD of both spine and legs. The GH was correlated with the BMD of whole body and spine (p<0.05). The TESTO was only correlated with BMD of the arms (p<0.01). The best predictor of BMD measurements is GSNDA. This study has proved the osteogenic effect of combat sports practice, especially judo and karate kyokushinkai. Therefore, children and adolescent should be encouraged to participate in combat sport. Moreover, it suggested that the best model predicting BMD in different sites among adolescent combat sports athletes was the GSNDA. PMID:22980488

  17. Combat sports practice favors bone mineral density among adolescent male athletes.

    PubMed

    Nasri, Raouf; Hassen Zrour, Saoussen; Rebai, Haithem; Neffeti, Fadoua; Najjar, Mohamed Fadhel; Bergaoui, Naceur; Mejdoub, Hafedh; Tabka, Zouhair

    2015-01-01

    The aim of this study was to determine the impact of combat sports practice on bone mineral density (BMD) and to analyze the relationship between bone parameters and anthropometric measurements, bone markers, and activity index (AI). In other words, to detect the most important determinant of BMD in the adolescent period among combat sports athletes. Fifty athletes engaged in combat sports, mean age 17.1±0.2 yr, were compared with 30 sedentary subjects who were matched for age, height, and pubertal stage. For all subjects, the whole-body BMD, lumbar spine BMD (L2-L4), and BMD in the pelvis, arms, and legs was measured by dual-energy X-ray absorptiometry, and anthropometric measurements were evaluated. Daily calcium intake, bone resorption, and formation markers were measured. BMD measurements were greater in the combat sports athletes than in the sedentary group (p<0.01). Weight, body mass index, and lean body mass were significantly correlated with BMD in different sites. Daily calcium consumption lower than daily calcium intake recommended in both athletes and sedentary group. AI was strongly correlated with all BMD measurements particularly with the whole body, legs, and arms. Negative correlations were observed between bone markers and BMD in different sites. The common major predictor of BMD measurements was AI (p<0.0001). AI associated to lean body mass determined whole-body BMD until 74%. AI explained both BMD in arms and L2-L4 at 25%. AI associated to height can account for 63% of the variance in BMD legs. These observations suggested that the best model predicting BMD in different sites among adolescent combat sports athletes was the AI. Children and adolescents should be encouraged to participate in combat sports to maximize their bone accrual. PMID:24176431

  18. Grip strength is a predictor of bone mineral density among adolescent combat sport athletes.

    PubMed

    Nasri, Raouf; Hassen Zrour, Saoussen; Rebai, Haithem; Fadhel Najjar, Mohamed; Neffeti, Fadoua; Bergaoui, Naceur; Mejdoub, Hafedh; Tabka, Zouhair

    2013-01-01

    The aim of this study was firstly to investigate the correlation between bone parameters and grip strength (GS) in hands, explosive legs power (ELP), and hormonal parameters; second, to identify the most determinant variables of bone mineral density (BMD) among adolescent combat sport athletes. Fifty combat sport athletes aged 17.1 ± 0.2 year were compared with 30 sedentary subjects matched for age, height, and pubertal stage. For all subjects, the BMD in deferent sites associated with anthropometric parameters were measured by dual-energy X-ray absorptiometry. The growth hormone (GH) and testosterone (TESTO) concentrations were tested. The GS in dominant (GSDA) and nondominant arms (GSNDA) and ELP were evaluated. All BMD measured were greater in athletes than in sedentary group (p<0.01). The GS and ELP showed higher values in athletes than in sedentary group (p<0.01). The BMD in all sites were correlated with weight, but without correlation with height. The GSNDA and ELP were significantly correlated with BMD of both spine and legs. The GH was correlated with the BMD of whole body and spine (p<0.05). The TESTO was only correlated with BMD of the arms (p<0.01). The best predictor of BMD measurements is GSNDA. This study has proved the osteogenic effect of combat sports practice, especially judo and karate kyokushinkai. Therefore, children and adolescent should be encouraged to participate in combat sport. Moreover, it suggested that the best model predicting BMD in different sites among adolescent combat sports athletes was the GSNDA.

  19. Single-leg postural stability deficits following anterior cruciate ligament reconstruction in pediatric and adolescent athletes.

    PubMed

    Sugimoto, Dai; Howell, David R; Micheli, Lyle J; Meehan, William P

    2016-07-01

    The objective of this study was to compare the postural stability of pediatric and adolescent athletes without anterior cruciate ligament injury with those who underwent anterior cruciate reconstruction (ACLR). Postural stability ratings derived from a video-force plate system during the three stances of the modified Balance Error Scoring System were collected from pediatric and adolescent athletes who underwent ACLR (N=24; mean 1.2 years after surgery) and from uninjured controls (N=479). The postural control rating was calculated as the mean of the displacement and variance of the torso and center of pressure data, normalized on a scale from 0 to 100. A higher rating indicates greater postural stability. Participants who underwent ACLR showed lower postural stability ratings during single-leg stance compared with uninjured controls (40.0 vs. 48.7; P=0.037). ACLR is associated with deficits in postural stability.

  20. Coaching behaviors, motivational climate, and psychosocial outcomes among female adolescent athletes.

    PubMed

    Weiss, Maureen R; Amorose, Anthony J; Wilko, Anna Marie

    2009-11-01

    Based on Harter's (12,13) competence motivation theory, this study examined the relationship of coaches' performance feedback and motivational climate with female athletes' perceived competence, enjoyment, and intrinsic motivation. Female adolescent soccer players (N = 141) completed measures of relevant constructs toward the latter part of their season. Canonical correlation analysis revealed that athletes' perceptions of greater positive and informational feedback given by coaches in response to successful performance attempts, greater emphasis placed on a mastery climate, and less emphasis placed on a performance climate, were significantly related to greater ability perceptions, enjoyment, and intrinsic motivation. Exploratory analyses also showed that the relationship between feedback and the psychosocial outcomes may vary as a function of the perceived motivational climate. Overall, these results suggest that coaching feedback and motivational climate are important contributors to explaining adolescent females' continued motivation to participate in sport.

  1. Myocardial infarction caused by myocardial bridging in a male adolescent athlete.

    PubMed

    Zhu, Cheng-Gang; Liu, Jun; Liu, Wei-Dong; Xu, Yan-Lu; Wu, Na-Qiong; Guo, Yuan-Lin; Tang, Yi-Da; Jiang, Li-Xin; Li, Jian-Jun

    2012-02-01

    Myocardial bridging is a common congenital abnormality of a coronary artery, and is usually thought to be a benign anatomical variant. Although rare, previous studies have reported that patients with myocardial bridging may suffer from myocardial ischemia, myocardial infarction (MI), arrhythmias and even sudden death. Here we report the case of an 18-year-old adolescent athlete with myocardial bridging resulting in MI. Coronary angiography revealed 80% luminal narrowing by systolic compression in the proximal and mid segments of the left anterior descending coronary artery, which returned to normal during diastole. We considered that heavy sports might be a potential trigger for his MI attack. Therefore, special attention should be paid to this kind of athlete, especially if adolescent.

  2. Beliefs about the causes of success in sports and susceptibility for doping use in adolescent athletes.

    PubMed

    Barkoukis, Vassilis; Lazuras, Lambros; Tsorbatzoudis, Haralambos

    2014-01-01

    The present study set out to assess the impact of attributional beliefs about success on the susceptibility for doping use in adolescent athletes. The sample consisted of 309 adolescent athletes participating in both team and individual sports. Participants completed a battery of questionnaires including Beliefs about the Causes of Success in Sport Questionnaire (BACSSQ), current and past doping use, and measures of attitudes, norms, situational temptation and social desirability. Variance reduction rate analysis revealed that social desirability did not act as a confounder in the relationship between doping susceptibility and its predictors. With regard to beliefs about the causes of success dimensions, only deception emerged as a significant predictor of doping use susceptibility over and above the effects of well-established social-cognitive predictors of doping intentions and use. These findings imply that beliefs about the causes of success in youth sports may comprise another dimension of risk factors for doping susceptibility and use.

  3. The Relationship between Selected Motor Ability Determinants and Anthropometric Characteristics in Adolescent Athletes from Various Sport.

    PubMed

    Maćkala, Krzysztof; Michalski, Ryszard; Stodólka, Jacek; Rausavljević, Nikola; Čoh, Milan

    2015-07-01

    The main purpose of this study was to examine the relationship between speed, lower extremities explosive power, simple, and complex responses in adolescent athletes from various disciplines. Thirty nine athletes of 16.5 years old, N = 13 sprinters and jumpers, N = 13 soccer players, and N = 13 judokas participated in the experiment. Pearson correlations, a one-way ANOVA and an independent t-test for establishing differences between those three groups of athletes was applied. Additionally the Ward method of hierarchical cluster analysis also was applied. The strong correlation occurred between complex responses and speed; 20 m from standing and 20 m flying start (r = 0.62 and r = 0.65 respectively). In other cases, no strong association was found. The substantial differences between groups occurred in the 20 m run from flying start (t = 5.92) and standing triple jump (t = 4.16). The study indicates that adolescent athletes may need to be assessed differently to a certain extent, including sport specialization. PMID:26434022

  4. A case of early sports specialization in an adolescent athlete.

    PubMed

    Ferguson, Brad; Stern, Paula J

    2014-12-01

    Early sport specialization (ESS) refers to intense year round training in a specific sport with the exclusion of other sports at a young age. This approach to training is heavily debated and there are claims both in support and against ESS. ESS is considered to be more common in the modern day youth athlete and could be a source of overuse injuries and burnout. This case describes a 16 year old elite level baseball pitcher who engaged in high volume, intense training at a young age which lead to several significant throwing related injuries. The case highlights the historical context of ESS, the potential risk and benefits as well as the evidence for its effectiveness. It is important for health care professionals to be informed on the topic of ESS in order to educate athletes, parents, coaches and organizations of the potential risks and benefits.

  5. A case of early sports specialization in an adolescent athlete

    PubMed Central

    Ferguson, Brad; Stern, Paula J.

    2014-01-01

    Early sport specialization (ESS) refers to intense year round training in a specific sport with the exclusion of other sports at a young age. This approach to training is heavily debated and there are claims both in support and against ESS. ESS is considered to be more common in the modern day youth athlete and could be a source of overuse injuries and burnout. This case describes a 16 year old elite level baseball pitcher who engaged in high volume, intense training at a young age which lead to several significant throwing related injuries. The case highlights the historical context of ESS, the potential risk and benefits as well as the evidence for its effectiveness. It is important for health care professionals to be informed on the topic of ESS in order to educate athletes, parents, coaches and organizations of the potential risks and benefits. PMID:25550662

  6. Clinical concepts for treatment of the elbow in the adolescent overhead athlete.

    PubMed

    Ellenbecker, Todd S; Reinold, Michael; Nelson, Cory O

    2010-10-01

    Injuries to the adolescent elbow are common because of the repetitive overuse inherent in many overhead sport activities. The management of these patients is greatly facilitated through a greater understanding of the demands placed on the upper extremity kinetic chain during these overhead activities as well as a detailed examination and rehabilitation for the entire upper extremity kinetic chain. Particular emphasis on improving rotator cuff strength and muscular endurance, along with scapular stabilization, is a critical part of elbow rehabilitation in these patients. In addition, the use of a strategic and progressive interval sport return program is necessary to minimize reinjury and return the adolescent overhead athlete to full function.

  7. Effects of Hypohydration on Repeated 40-yd Sprint Performance.

    PubMed

    Gann, Joshua J; Green, James M; OʼNeal, Eric K; Renfroe, Lee G; Andre, Thomas L

    2016-04-01

    This study examined the effects of hypohydration on repeated 40-yd sprint performance. Anaerobically fit current and former Division II male athletes (n = 12) completed 2 bouts of 10 × 40-yd sprints followed by an agility test, dehydrated (∼3% body weight [DT]), or hydrated trial (HT). Statistical analysis of group means indicated that hypohydration had little effect on sprint times for either the first (DT= 5.38 ± 0.37; HT = 5.35 ± 0.34) or second (DT = 5.47 ± 0.39; HT = 5.42 ± 0.39) bout of 10 sprints with only sprint number 2, 5, and 6 of bout 2 reaching statistical significance. However, when individual sprint performance was considered, a greater effect was seen. In all, 83% (10 of 12) of subjects experienced a meaningful change (≥0.1 seconds) (positive or negative) in mean sprint time (DT vs. HT) for one or more bout of 10 sprints. Ratings of perceived exertion was significantly higher (∼1 unit on a 10 point scale) for DT in all sprints during bout 1 and the first 2 sprints of bout 2. These results indicate that the effect of hypohydration on repeated sprint performance varies among individuals. Some improved performance with hypohydration, while others experienced detrimental effects. Hypohydration also resulted in a particularly notable negative impact on perceptual measures of exertion even when performance was similar.

  8. Biomechanics of sprint running. A review.

    PubMed

    Mero, A; Komi, P V; Gregor, R J

    1992-06-01

    Understanding of biomechanical factors in sprint running is useful because of their critical value to performance. Some variables measured in distance running are also important in sprint running. Significant factors include: reaction time, technique, electromyographic (EMG) activity, force production, neural factors and muscle structure. Although various methodologies have been used, results are clear and conclusions can be made. The reaction time of good athletes is short, but it does not correlate with performance levels. Sprint technique has been well analysed during acceleration, constant velocity and deceleration of the velocity curve. At the beginning of the sprint run, it is important to produce great force/power and generate high velocity in the block and acceleration phases. During the constant-speed phase, the events immediately before and during the braking phase are important in increasing explosive force/power and efficiency of movement in the propulsion phase. There are no research results available regarding force production in the sprint-deceleration phase. The EMG activity pattern of the main sprint muscles is described in the literature, but there is a need for research with highly skilled sprinters to better understand the simultaneous operation of many muscles. Skeletal muscle fibre characteristics are related to the selection of talent and the training-induced effects in sprint running. Efficient sprint running requires an optimal combination between the examined biomechanical variables and external factors such as footwear, ground and air resistance. Further research work is needed especially in the area of nervous system, muscles and force and power production during sprint running. Combining these with the measurements of sprinting economy and efficiency more knowledge can be achieved in the near future.

  9. The Influence of Significant Others on Attitudes, Subjective Norms and Intentions Regarding Dietary Supplement Use among Adolescent Athletes.

    ERIC Educational Resources Information Center

    Dunn, Michael S.; Eddy, James M.; Qi Wang, Min; Nagy, Steve; Perko, Michael A.; Bartee, R. Todd

    2001-01-01

    The purpose of this study was: (1) to determine whether attitudes are a better predictor of adolescents' intentions to use dietary supplements than are subjective norms, and (2) to assess the influence of significant others on attitudes, subjective norms, and intentions among adolescent athletes. Results indicated that attitudes were a better…

  10. Effect of a Nutritional Intervention in Athlete's Body Composition, Eating Behaviour and Nutritional Knowledge: A Comparison between Adults and Adolescents.

    PubMed

    Nascimento, Marcus; Silva, Danielle; Ribeiro, Sandra; Nunes, Marco; Almeida, Marcos; Mendes-Netto, Raquel

    2016-09-07

    The objective of the present study is to evaluate and compare the effect of a nutritional intervention between adolescent and adult. In a before and after quasi-experimental clinical study, 32 athletes (21 adults, age range 20-32 years; 11 adolescents, age range: 12-19 years) participated in a nutritional counselling consisting of four consultations separated by an interval of 45 to 60 days. The athlete's eating behaviour, body composition and nutrition knowledge were evaluated at the beginning and at the end of the protocol. Both groups increased lean body mass and nutritional knowledge. Adolescents increased their mid-arm muscle circumference and improved meal frequency, and daily water intake. Athletes of both groups improved their ingestion of vegetables and fruits and decreased the ingestion of sweets and oils. Adolescents showed a higher prevalence of individuals that remained within or approached to the recommendations of sweets. This is the first study to evaluate and compare the effect of a nutritional intervention between adolescent and adult athletes body composition, eating behaviour and nutritional knowledge. The nutritional counselling has been effective in promoting beneficial changes on the athlete's eating behaviour, nutritional knowledge and body composition, however, some healthy changes were only experienced by adolescents, especially in the frequency of meals and the intake of sweets.

  11. Effect of a Nutritional Intervention in Athlete's Body Composition, Eating Behaviour and Nutritional Knowledge: A Comparison between Adults and Adolescents.

    PubMed

    Nascimento, Marcus; Silva, Danielle; Ribeiro, Sandra; Nunes, Marco; Almeida, Marcos; Mendes-Netto, Raquel

    2016-01-01

    The objective of the present study is to evaluate and compare the effect of a nutritional intervention between adolescent and adult. In a before and after quasi-experimental clinical study, 32 athletes (21 adults, age range 20-32 years; 11 adolescents, age range: 12-19 years) participated in a nutritional counselling consisting of four consultations separated by an interval of 45 to 60 days. The athlete's eating behaviour, body composition and nutrition knowledge were evaluated at the beginning and at the end of the protocol. Both groups increased lean body mass and nutritional knowledge. Adolescents increased their mid-arm muscle circumference and improved meal frequency, and daily water intake. Athletes of both groups improved their ingestion of vegetables and fruits and decreased the ingestion of sweets and oils. Adolescents showed a higher prevalence of individuals that remained within or approached to the recommendations of sweets. This is the first study to evaluate and compare the effect of a nutritional intervention between adolescent and adult athletes body composition, eating behaviour and nutritional knowledge. The nutritional counselling has been effective in promoting beneficial changes on the athlete's eating behaviour, nutritional knowledge and body composition, however, some healthy changes were only experienced by adolescents, especially in the frequency of meals and the intake of sweets. PMID:27618088

  12. Velocity thresholds for women's soccer matches: sex specificity dictates high-speed running and sprinting thresholds - Female Athletes in Motion (FAiM).

    PubMed

    Bradley, Paul S; Vescovi, Jason D

    2015-01-01

    There is no methodological standardization of velocity thresholds for the quantification of distances covered in various locomotor activities for women's soccer matches, especially for high-speed running and sprinting. Applying velocity thresholds used for motion analysis of men's soccer has likely created skewed observations about high-intensity movement demands for the women's game because these thresholds do not accurately reflect the capabilities of elite female players. Subsequently, a cohesive view of the locomotor characteristics of women's soccer does not yet exist. The aim of this commentary is to provide suggestions for standardizing high-speed running and sprint velocity thresholds specific to women's soccer. The authors also comment on using generic vs individualized thresholds, as well as age-related considerations, to establish velocity thresholds.

  13. Skeletal mass in adolescent male athletes and nonathletes: relationships with high-impact sports.

    PubMed

    Dias Quiterio, Ana L; Carnero, Elvis A; Baptista, Fátima M; Sardinha, Luís B

    2011-12-01

    Dias Quiterio, AL, Canero, EA, Baptista, FM, and Sardinha, LB. Skeletal mass in adolescent male athletes and nonathletes: relationships with high-impact sports. J Strength Cond Res 25(12): 3439-3447, 2011-This study examined the relationships between the practice of different categories of sports (high-impact vs. nonimpact) and bone status in adolescent male athletes and investigated differences from an age-matched control group. A total of 54 adolescent male athletes and 26 adolescent nonathletes were evaluated. Bone mineral density, bone mineral content (BMC), and bone area at the whole-body, limbs, and lumbar spine were determined by dual-energy x-ray absorptiometry, along with total and regional fat-free mass and body fat. The high-impact group included 34 athletes: 9 gymnasts, 18 basketball players, and 7 handball players (age: 15.7 ± 1.6 years; weight: 72.0 ± 15.0 kg; height: 178.5 ± 12.5 cm). The nonimpact group consisted of 20 swimmers (age: 16.4 ± 2.5 years; weight: 66.9 ± 10.4 kg; height: 173.7 ± 10.9 cm). The nonathletic control group included 26 male adolescents (age: 15.9 ± 2.8 years; weight: 64.7 ± 16.3 kg; height: 168.6 ± 15.1 cm). No differences were observed between the nonimpact and the control group in all bone variables, before and after adjustments for maturation level, body weight, and height (p > 0.05). After adjustments for these variables, the high-impact group displayed greater bone mass in most of the measured sites when compared to the other 2 groups (p < 0.001). Subjects in the nonimpact group showed lower values of BMC, particularly in the lower limbs, than both the high-impact and the nonathletic control groups (p < 0.05) after adjustments for maturation, high, and fat-free mass. This study reinforces the positive associations between high-impact physical activities and skeletal health in adolescent boys.

  14. Performance Development in Adolescent Track and Field Athletes According to Age, Sex and Sport Discipline

    PubMed Central

    Tønnessen, Espen; Svendsen, Ida Siobhan; Olsen, Inge Christoffer; Guttormsen, Atle; Haugen, Thomas

    2015-01-01

    Introduction Sex-specific differences that arise during puberty have a pronounced effect on the training process. However, the consequences this should have for goal-setting, planning and implementation of training for boys and girls of different ages remains poorly understood. The aim of this study was to quantify performance developments in athletic running and jumping disciplines in the age range 11-18 and identify progression differences as a function of age, discipline and sex. Methods The 100 all-time best Norwegian male and female 60-m, 800-m, long jump and high jump athletes in each age category from 11 to 18 years were analysed using mixed models with random intercept according to athlete. Results Male and female athletes perform almost equally in running and jumping events up to the age of 12. Beyond this age, males outperform females. Relative annual performance development in females gradually decreases throughout the analyzed age period. In males, annual relative performance development accelerates up to the age of 13 (for running events) or 14 (for jumping events) and then gradually declines when approaching 18 years of age. The relative improvement from age 11 to 18 was twice as high in jumping events compared to running events. For all of the analyzed disciplines, overall improvement rates were >50% higher for males than for females. The performance sex difference evolves from < 5% to 10-18% in all the analyzed disciplines from age 11 to 18 yr. Conclusion To the authors’ knowledge, this is the first study to present absolute and relative annual performance developments in running and jumping events for competitive athletes from early to late adolescence. These results allow coaches and athletes to set realistic goals and prescribe conditioning programs that take into account sex-specific differences in the rate of performance development at different stages of maturation. PMID:26043192

  15. Dispositional coping, coping effectiveness, and cognitive social maturity among adolescent athletes.

    PubMed

    Nicholls, Adam R; Perry, John L; Jones, Leigh; Morley, Dave; Carson, Fraser

    2013-06-01

    It is accepted among scholars that coping changes as people mature during adolescence, but little is known about the relationship between maturity and coping. The purpose of this paper was to assess a model, which included dispositional coping, coping effectiveness, and cognitive social maturity. We predicted that cognitive social maturity would have a direct effect on coping effectiveness, and also an indirect impact via dispositional coping. Two hundred forty-five adolescent athletes completed measures of dispositional coping, coping effectiveness, and cognitive social maturity, which has three dimensions: conscientiousness, peer influence on behavior, and rule following. Using structural equation modeling, we found support for our model, suggesting that coping is related to cognitive social maturity. This information can be used to influence the content of coping interventions for adolescents of different maturational levels.

  16. Analysis of Consumption of Energy Drinks by a Group of Adolescent Athletes

    PubMed Central

    Nowak, Dariusz; Jasionowski, Artur

    2016-01-01

    Background: Energy drinks (EDs) have become widely popular among young adults and, even more so, among adolescents. Increasingly, they are consumed by athletes, particularly those who have just begun their sporting career. Uncontrolled and high consumption of EDs, in addition to other sources of caffeine, may pose a threat to the health of young people. Hence, our objective was to analyze the consumption of EDs among teenagers engaged in sports, including quantity consumed, identification of factors influencing consumption, and risks associated with EDs and EDs mixed with alcohol (AmEDs). Methods: The study involved a specially designed questionnaire, which was completed by 707 students, 14.3 years of age on average, attending secondary sports schools. Results: EDs were consumed by 69% of the young athletes, 17% of whom drank EDs quite often: every day or 1–3 times a week. Most respondents felt no effects after drinking EDs, but some reported symptoms, including insomnia, anxiety, tachycardia, nervousness and irritability. The major determinant of the choice of EDs was taste (47%), followed by price (21%). One in ten respondents admitted to consumption of AmEDs. Among the consequences reported were: abdominal pains, nausea, vomiting, amnesia, headache, and hangover. Conclusions: EDs consumption among adolescent athletes was relatively high. Considering the habit of AmEDs and literature data, it is worth emphasizing that it may lead to health problems in the near future, alcohol- or drug-dependence, as well as other types of risk behaviour. PMID:27483299

  17. Recovery of Psychological Readiness May Differ Between Genders Following ACL Reconstruction in Adolescent Athletes

    PubMed Central

    Milewski, Matthew David; Kostyun, Regina; Iannicelli, Julie P.; Kostyun, Kyle J.; Solomito, Matthew; Nissen, Carl W.

    2016-01-01

    Objectives: Injury to the anterior cruciate ligament (ACL) is a traumatic and emotional event for adolescent athletes. Preparation to return to play (RTP) and the potential risk of re-injury are often equally as emotional as the injury, and have been identified as possible limiting factors to a successful rehabilitation and RTP. In order to create a comprehensive rehabilitation model, further understanding of psychological readiness following surgical intervention is needed. The purpose of this study was to determine if clinical outcomes of subjective knee function and psychological readiness differ between genders following ACL reconstruction surgery in adolescent athletes, and if higher knee function and physiological readiness was associated with an earlier to RTP. Methods: Athletes who underwent ACL reconstruction surgery and were successfully returned back to unrestricted sport were included in the analysis. At approximately six months post surgery, knee function was assessed using the validated International Knee Documentation Committee (IKDC) Subjective Form, and psychological readiness was assessed using the validated ACL-Return to Sport after Injury (ACL-RSI) scale. Formal clearance to resume unrestricted sport was obtained from clinic notes. A T-test was used to determine if demographics, IKDC and ACL-RSI scores between genders. A mixed effects random intercept regression model was used to determine the association of time to RTP with IKDC and ACL-RSI scores. Results: A total of 45 adolescent athletes (23 females) were included in this analysis. No significant differences were found between males and females for age (16.2±1.5 years, 16.3±2.2 years) and average time to RTP (7.3±2.0 months, 7.3±1.8 months). No significant differences in IKDC scores were found between males and females (88±10%, 87±10%). A trend was identified that males demonstrated higher ACL-RSI scores at six month post surgery than females (81±14%, 72±17%, p = 0.063). In females

  18. Repetitive Concussions in Adolescent Athletes – Translating Clinical and Experimental Research into Perspectives on Rehabilitation Strategies

    PubMed Central

    Semple, Bridgette D.; Lee, Sangmi; Sadjadi, Raha; Fritz, Nora; Carlson, Jaclyn; Griep, Carrie; Ho, Vanessa; Jang, Patrice; Lamb, Annick; Popolizio, Beth; Saini, Sonia; Bazarian, Jeffrey J.; Prins, Mayumi L.; Ferriero, Donna M.; Basso, D. Michele; Noble-Haeusslein, Linda J.

    2015-01-01

    Sports-related concussions are particularly common during adolescence, a time when even mild brain injuries may disrupt ongoing brain maturation and result in long-term complications. A recent focus on the consequences of repetitive concussions among professional athletes has prompted the development of several new experimental models in rodents, as well as the revision of guidelines for best management of sports concussions. Here, we consider the utility of rodent models to understand the functional consequences and pathobiology of concussions in the developing brain, identifying the unique behavioral and pathological signatures of concussive brain injuries. The impact of repetitive concussions on behavioral consequences and injury progression is also addressed. In particular, we focus on the epidemiological, clinical, and experimental evidence underlying current recommendations for physical and cognitive rest after concussion, and highlight key areas in which further research is needed. Lastly, we consider how best to promote recovery after injury, recognizing that optimally timed, activity-based rehabilitative strategies may hold promise for the adolescent athlete who has sustained single or repetitive concussions. The purpose of this review is to inform the clinical research community as it strives to develop and optimize evidence-based guidelines for the concussed adolescent, in terms of both acute and long-term management. PMID:25883586

  19. Avulsion of the iliac crest apophysis: a rare fracture in adolescent athletes.

    PubMed

    Lambert, M J; Fligner, D J

    1993-07-01

    We report a case of an iliac apophyseal fracture in a 15-year-old boy, sustained while swinging a baseball bat. He presented with right hip pain one hour after the injury occurred. Diagnosis was made on the basis of radiographs of the pelvis. Pelvic avulsion fractures are uncommon injuries, seen almost exclusively in adolescent athletes. The iliac crest is an unusual site of injury for this avulsion fracture. Only one other well-described case of an acute, noncontact fracture of the iliac apophysis with a similar mechanism of injury has been reported.

  20. Sprint performance under heat stress: A review.

    PubMed

    Girard, O; Brocherie, F; Bishop, D J

    2015-06-01

    Training and competition in major track-and-field events, and for many team or racquet sports, often require the completion of maximal sprints in hot (>30 °C) ambient conditions. Enhanced short-term (<30 s) power output or single-sprint performance, resulting from transient heat exposure (muscle temperature rise), can be attributed to improved muscle contractility. Under heat stress, elevations in skin/core temperatures are associated with increased cardiovascular and metabolic loads in addition to decreasing voluntary muscle activation; there is also compelling evidence to suggest that large performance decrements occur when repeated-sprint exercise (consisting of brief recovery periods between sprints, usually <60 s) is performed in hot compared with cool conditions. Conversely, poorer intermittent-sprint performance (recovery periods long enough to allow near complete recovery, usually 60-300 s) in hotter conditions is solely observed when exercise induces marked hyperthermia (core temperature >39 °C). Here we also discuss strategies (heat acclimatization, precooling, hydration strategies) employed by "sprint" athletes to mitigate the negative influence of higher environmental temperatures.

  1. Sprint performance under heat stress: A review.

    PubMed

    Girard, O; Brocherie, F; Bishop, D J

    2015-06-01

    Training and competition in major track-and-field events, and for many team or racquet sports, often require the completion of maximal sprints in hot (>30 °C) ambient conditions. Enhanced short-term (<30 s) power output or single-sprint performance, resulting from transient heat exposure (muscle temperature rise), can be attributed to improved muscle contractility. Under heat stress, elevations in skin/core temperatures are associated with increased cardiovascular and metabolic loads in addition to decreasing voluntary muscle activation; there is also compelling evidence to suggest that large performance decrements occur when repeated-sprint exercise (consisting of brief recovery periods between sprints, usually <60 s) is performed in hot compared with cool conditions. Conversely, poorer intermittent-sprint performance (recovery periods long enough to allow near complete recovery, usually 60-300 s) in hotter conditions is solely observed when exercise induces marked hyperthermia (core temperature >39 °C). Here we also discuss strategies (heat acclimatization, precooling, hydration strategies) employed by "sprint" athletes to mitigate the negative influence of higher environmental temperatures. PMID:25943658

  2. Monitoring of immunological parameters in adolescent basketball athletes during and after a sports season.

    PubMed

    Brunelli, Diego Trevisan; Rodrigues, Ariel; Lopes, Wendell Arthur; Gáspari, Arthur Fernandes; Bonganha, Valéria; Montagner, Paulo César; Borin, João Paulo; Cavaglieri, Cláudia Regina

    2014-01-01

    The objective of the present study was to monitor the immunological and hormonal responses and the occurrence of upper respiratory symptoms in adolescent basketball athletes during the different stages of a sports season. Anthropometric measures, biochemical analyses (interleukin-6, interleukin-10, tumour necrosis factor-alpha, C-reactive protein, testosterone and cortisol), neuromuscular evaluations (standing vertical jumping ability, agility and estimated VO2max) and leukocyte counts were performed at four moments: 72 h before the season (-72 h); before the season (Pre-season); after six weeks, at the end of the preparatory period (Preparatory); and after 20 weeks, at the end of the competitive period (Competitive). Also, the occurrence of upper respiratory symptoms was collected weekly during all stages of the season. There were significant increases in monocytes, cortisol, tumour necrosis factor-alpha and C-reactive protein at the Competitive moment as compared to the Pre-season. In addition, interleukin-10 decreased at the Competitive moment as compared to the Pre-season. Occurrence of upper respiratory symptoms demonstrated increases (38%) during the competitive period as compared to the preparatory. These results suggest that periods of training and competition could increase the occurrence of upper respiratory symptoms in adolescent athletes and this may be due to the unwanted effects of an inflammatory process in response to the excessive stress of training and competition.

  3. Sex steroid and growth hormone supplementation to enhance performance in adolescent athletes.

    PubMed

    Rogol, A D

    2000-08-01

    Ergogenic aids are taken to enhance energy utilization by producing more, controlling its use, or increasing mechanical efficiency. Most athletes are looking toward enhancing performance by proper training modalities and methods; however, some look to the biochemical route for a "quick fix." Thus, the use of chemical agents is on the rise. Herein is provided information on the anabolic-androgenic agents androstenedione, dehydroepiandrosterone, and the "parent" compound, testosterone. The former two, at best, have equivocal activity, but testosterone is both anabolic and androgenic in doses that adolescents might receive. Growth hormone and insulin-like growth factor-1 are anabolic, nonandrogenic compounds with undoubted effects on the lean body mass compartment. Both are expensive, not readily available, and subject to the art of counterfeiting. Thus, very few data are available in non-growth hormone-deficient adolescents. The discussion of these agents ends with issues of fairness, ethics, and the message we attempt to project to our teenagers, whether athletes or not. PMID:10943821

  4. The Acute Potentiating Effects of Heavy Sled Pulls on Sprint Performance.

    PubMed

    Winwood, Paul W; Posthumus, Logan R; Cronin, John B; Keogh, Justin W L

    2016-05-01

    This study examined the acute potentiating effects of heavy sprint-style sled pulls on sprint performance. Twenty-two experienced resistance-trained rugby athletes performed 2 heavy sprint-style sled pull training protocols on separate occasions using a randomized, crossover, and counterbalanced design. The protocols consisted of 2-baseline 15 m sprints followed by 15 m sprints at 4, 8, and 12 minutes after completing 15 and 7.5 m heavy sled pulls with loads of 75 and 150% body mass (respectively). A significantly faster (p ≤ 0.05) 15 m sprint time was observed at 12 minutes for the 75% body mass load. Small nonsignificant improvements (effect size [ES] = 0.22-0.33) in 5, 10, and 15 m sprint times were observed at 8 and 12 minutes after the 75% body mass sled pull. No significant changes were observed for any sprint time after the 150% body mass sled pull. Significant differences in the percentage of change in sprint times between the 2 sled pull conditions were observed at 4 (ES = 0.44-0.52), 8 (ES = 0.59), and 12 minutes (ES = 0.64). It would seem that the 75% body mass sled pull can be an effective preload stimulus for improving subsequent sprint performance provided that adequate recovery (8-12 minutes) is allowed. Practitioners should be advised that prescription of training load based on decrement in sprint velocity may be the best approach to determine loading for athletes.

  5. Coaching the Vegetarian Athlete

    ERIC Educational Resources Information Center

    Mandali, Swarna L.

    2011-01-01

    Good nutrition is important for optimal athletic performance. Adolescent athletes often depend on their coaches for nutritional information on weight management, dietary supplements, and dietary practices. Some dietary practices, such as vegetarianism, have the potential to be harmful to the adolescent athlete if not followed with careful…

  6. Reliability of the one-repetition-maximum power clean test in adolescent athletes.

    PubMed

    Faigenbaum, Avery D; McFarland, James E; Herman, Robert E; Naclerio, Fernando; Ratamess, Nicholas A; Kang, Jie; Myer, Gregory D

    2012-02-01

    Although the power clean test is routinely used to assess strength and power performance in adult athletes, the reliability of this measure in younger populations has not been examined. Therefore, the purpose of this study was to determine the reliability of the 1-repetition maximum (1RM) power clean in adolescent athletes. Thirty-six male athletes (age 15.9 ± 1.1 years, body mass 79.1 ± 20.3 kg, height 175.1 ±7.4 cm) who had >1 year of training experience in weightlifting exercises performed a 1RM power clean on 2 nonconsecutive days in the afternoon following standardized procedures. All test procedures were supervised by a senior level weightlifting coach and consisted of a systematic progression in test load until the maximum resistance that could be lifted for 1 repetition using proper exercise technique was determined. Data were analyzed using an intraclass correlation coefficient (ICC[2,k]), Pearson correlation coefficient (r), repeated measures analysis of variance, Bland-Altman plot, and typical error analyses. Analysis of the data revealed that the test measures were highly reliable demonstrating a test-retest ICC of 0.98 (95% confidence interval = 0.96-0.99). Testing also demonstrated a strong relationship between 1RM measures in trials 1 and 2 (r = 0.98, p < 0.0001) with no significant difference in power clean performance between trials (70.6 ± 19.8 vs. 69.8 ± 19.8 kg). Bland-Altman plots confirmed no systematic shift in 1RM between trials 1 and 2. The typical error to be expected between 1RM power clean trials is 2.9 kg, and a change of at least 8.0 kg is indicated to determine a real change in lifting performance between tests in young lifters. No injuries occurred during the study period, and the testing protocol was well tolerated by all the subjects. These findings indicate that 1RM power clean testing has a high degree of reproducibility in trained male adolescent athletes when standardized testing procedures are followed and qualified

  7. ACTN3 Genotype, Athletic Status, and Life Course Physical Capability: Meta-Analysis of the Published Literature and Findings from Nine Studies

    PubMed Central

    Alfred, Tamuno; Ben-Shlomo, Yoav; Cooper, Rachel; Hardy, Rebecca; Cooper, Cyrus; Deary, Ian J; Gunnell, David; Harris, Sarah E; Kumari, Meena; Martin, Richard M; Moran, Colin N; Pitsiladis, Yannis P; Ring, Susan M; Sayer, Avan Aihie; Smith, George Davey; Starr, John M; Kuh, Diana; Day, Ian NM

    2011-01-01

    The ACTN3 R577X (rs1815739) genotype has been associated with athletic status and muscle phenotypes, although not consistently. Our objective was to conduct a meta-analysis of the published literature on athletic status and investigate its associations with physical capability in several new population-based studies. Relevant data were extracted from studies in the literature, comparing genotype frequencies between controls and sprint/power and endurance athletes. For life course physical capability, data were used from two studies of adolescents and seven studies in the Healthy Ageing across the Life Course (HALCyon) collaborative research program, involving individuals aged between 53 and 90+ years. We found evidence from the published literature to support the hypothesis that in Europeans the RR genotype is more common among sprint/power athletes compared with their controls. There is currently no evidence that the X allele is advantageous to endurance athleticism. We found no association between R577X and grip strength (P = 0.09, n = 7,672 in males; P = 0.90, n = 7,839 in females), standing balance, timed get up and go, or chair rises in our studies of physical capability. The ACTN3 R577X genotype is associated with sprint/power athletic status in Europeans, but does not appear to be associated with objective measures of physical capability in the general population. Hum Mutat 32:1–11, 2011. © 2011 Wiley-Liss, Inc. PMID:21542061

  8. The impact of lower extremity mass and inertia manipulation on sprint kinematics.

    PubMed

    Bennett, John P; Sayers, Mark G L; Burkett, Brendan J

    2009-12-01

    Resistance sprint training is a sprint-specific training protocol commonly employed by athletes and coaches to enhance sprint performance. This research quantified the impact of lower extremity mass and inertia manipulation on key temporal and kinematic variables associated with sprint performance. A 3-dimensional analysis of 40 m sprinting was conducted on 8 elite sprinters under normal conditions and resisted sprint training. Results of the study showed that lower extremity additional mass training (at 10% individual segment weight) led to a significant reduction in sprint time for both the 10-m to 20-m and the 30-m to 40-m splits and the total 40 m measure. The stride velocity throughout the 20-m to 30-m phase of the sprint trials was also shown to be significantly reduced in the lower extremity mass and inertia manipulation condition. Importantly, no significant differences were observed across the remaining spatiotemporal variables of stride length, stride frequency, total stride time, and ground contact time. For coaches and athletes, the addition of specific lower extremity mass could improve the athlete's sprint performance without any measured effect on the technique of highly trained elite sprinters. PMID:19855307

  9. Ankle moment generation and maximum-effort curved sprinting performance.

    PubMed

    Luo, Geng; Stefanyshyn, Darren

    2012-11-15

    Turning at high speed along acute curves is crucial for athletic performance. One determinant of curved sprinting speed is the ground reaction force that can be created by the supporting limb; the moment generated at the ankle joint may influence such force generation. Body lean associated with curved sprints positions the ankle joints in extreme in-/eversion, and may hinder the ankle moment generation. To examine the influence of ankle moment generation on curved sprinting performance, 17 male subjects performed maximum-effort curved sprints in footwear with and without a wedge. The wedged footwear was constructed with the intention to align the ankle joints closer to their neutral frontal-plane configuration during counter-clockwise curved sprints so greater joint moments might be generated. We found, with the wedged footwear, the average eversion angle of the inside leg ankle was reduced, and the plantarflexion moment generation increased significantly. Meanwhile, the knee extension moment remained unchanged. With the wedged footwear, stance-average centripetal ground reaction force increased significantly while no difference in the vertical ground reaction force was detected. The subjects created a greater centripetal ground reaction impulse in the wedged footwear despite a shortened stance phase when compared to the control. Stance-average curved sprinting speed improved by 4.3% with the wedged footwear. The changes in ankle moment and curved sprinting speed observed in the current study supports the notion that the moment generation at the ankle joint may be a performance constraint for curved sprinting. PMID:23022207

  10. The GH-IGF-I response to typical field sports practices in adolescent athletes: a summary.

    PubMed

    Eliakim, Alon; Cooper, Dan M; Nemet, Dan

    2014-11-01

    The present study compares previous reports on the effect of "real-life" typical field individual (i.e., cross-country running and wrestling--representing combat versus noncombat sports) and team sports (i.e., volleyball and water polo-representing water and land team sports) training on GH and IGF-1, the main growth factors of the GH→IGF axis, in male and female late pubertal athletes. Cross-country running practice and volleyball practice in both males and females were associated with significant increases of circulating GH levels, while none of the practices led to a significant increase in IGF-I levels. The magnitude (percent change) of the GH response to the different practices was determined mainly by preexercise GH levels. There was no difference in the training-associated GH response between individual and team sports practices. The GH response to the different typical practices was not influenced by the practice-associated lactate change. Further studies are needed to better understand the effect of real-life typical training in prepubertal and adolescent athletes and their role in exercise adaptations.

  11. Cardiac Dimensions in Elite Young Track Athletes.

    ERIC Educational Resources Information Center

    Tharp, Gerald D.; And Others

    1986-01-01

    The study compared young sprint and distance runners for changes in cardiac dimensions with increased age or increased body surface area. Results, which run counter to generalizations stated for adult athletes, are detailed. (Author/MT)

  12. DXA surrogates for visceral fat are inversely associated with bone density measures in adolescent athletes with menstrual dysfunction

    PubMed Central

    Ackerman, Kathryn E.; Davis, Brittany; Jacoby, Leah; Misra, Madhusmita

    2013-01-01

    Objective Lean mass is associated with bone mineral density (BMD) in athletes, attributable to the anabolic pull of muscle on bone. Fat mass is also important, and subcutaneous fat positively and visceral fat negatively correlates with BMD in obese adolescents. The contribution of regional body composition to low BMD in amenorrheic athletes (AA) has not been elucidated. We hypothesized that in adolescent athletes (runners), BMD is associated positively with total fat (surrogate for subcutaneous fat) and lean mass, and inversely with percent trunk fat and trunk-to-extremity fat ratio (surrogates for visceral fat). Design Cross-sectional study. Subjects and methods We examined BMD and body composition using dual energy X-ray absorptiometry (DXA) in 21 AA and 19 eumenorrheic athletes (EA) (12–18 years) (runners). We report total hip and height-adjusted BMD [lumbar bone mineral apparent density (LBMAD) and whole body bone mineral content/height (WBBMC/Ht)]. Results AA had lower BMD than EA. Lean mass was less strongly associated with hip BMD in AA than EA; fat mass was positively associated with LBMAD in EA. Percent trunk fat and trunk-to-extremity fat ratio were inversely associated with lumbar and WB measures in AA. In a regression model, lean and fat mass were positively, and percent trunk fat and trunk-to-extremity fat ratio negatively associated with LBMAD and WBBMC/Ht for all athletes, even after controlling for serum estradiol. Conclusions DXA surrogates for visceral fat are inversely associated with bone density in athletes. PMID:21932588

  13. Force production during maximal effort bend sprinting: Theory vs reality.

    PubMed

    Churchill, S M; Trewartha, G; Bezodis, I N; Salo, A I T

    2016-10-01

    This study investigated whether the "constant limb force" hypothesis can be applied to bend sprinting on an athletics track and to understand how force production influences performance on the bend compared with the straight. Force and three-dimensional video analyses were conducted on seven competitive athletes during maximal effort sprinting on the bend (radius 37.72 m) and straight. Left step mean peak vertical and resultant force decreased significantly by 0.37 body weight (BW) and 0.21 BW, respectively, on the bend compared with the straight. Right step force production was not compromised in the same way, and some athletes demonstrated substantial increases in these variables on the bend. More inward impulse during left (39.9 ± 6.5 Ns) than right foot contact (24.7 ± 5.8 Ns) resulted in 1.6° more turning during the left step on the bend. There was a 2.3% decrease in velocity from straight to bend for both steps. The constant limb force hypothesis is not entirely valid for maximal effort sprinting on the bend. Also, the force requirements of bend sprinting are considerably different to straight-line sprinting and are asymmetrical in nature. Overall, bend-specific strength and technique training may improve performance during this portion of 200- and 400-m races.

  14. The effect of resisted sprint training on maximum sprint kinetics and kinematics in youth.

    PubMed

    Rumpf, Michael C; Cronin, John B; Mohamad, Ikhwan N; Mohamad, Sharil; Oliver, Jon L; Hughes, Michael G

    2015-01-01

    Resisted sled towing is a popular and efficient training method to improve sprint performance in adults, however, has not been utilised in youth populations. The purpose therefore was to investigate the effect of resisted sled towing training on the kinematics and kinetics of maximal sprint velocity in youth of different maturation status. Pre- and post-intervention 30 metre sprint performance of 32 children, 18 pre-peak height velocity (PHV) and 14 mid-/post-PHV, were tested on a non-motorised treadmill. The 6-week intervention consisted of ∼12 sessions for pre-PHV and 14 for mid-/post-PHV of resisted sled towing training with each sessions comprised of 8-10 sprints covering 15-30 metres with a load of 2.5, 5, 7.5 or 10% body mass. Pre-PHV participants did not improve sprint performance, while the mid-/post-PHV participants had significant (P < 0.05) reductions (percent change, effect size) in sprint time (-5.76, -0.74), relative leg stiffness (-45.0, -2.16) and relative vertical stiffness (-17.4, -0.76) and a significant increase in average velocity (5.99, 0.76), average step rate (5.65, 0.53), average power (6.36, 0.31), peak horizontal force (9.70, 0.72), average relative vertical forces (3.45, 1.70) and vertical displacement (14.6, 1.46). It seems that sled towing may be a more suitable training method in mid-/post-PHV athletes to improve 30 metre sprint performance.

  15. Echocardiographic characteristics in adolescent junior male athletes of different sport events.

    PubMed

    Petridis, L; Kneffel, Zs; Kispéter, Zs; Horváth, P; Sidó, Z; Pavlik, G

    2004-01-01

    The purpose of this study was to examine the effects of different sport activities on cardiac adaptation. Echocardiographic data of 137 athletes and 21 non-athletes were measured and compared in two age groups 15-16 and 17-18 years of age. Athletes belonged into three groups according to their sports activity (endurance events, power athletes, ball game players). The observed variables were related to body size by indices in which the exponents of the numerator and the denominator were matched. Left ventricular hypertrophy was manifest in all athletic groups. Power athletes had the largest mean left ventricular wall thickness (LVWTd) in both age groups. In the older age group differences between the athletic groups were smaller, but the endurance and power athletes had significantly higher wall thickness. Left ventricular internal diameter (LVIDd) was the largest in the endurance athletes, while mean relative muscle mass (LVMM) was the largest in the power athletes. LVMM of the older endurance athletes was significantly larger. Muscular quotient (MQ) was the highest in the endurance athletes; in the 17-18-year group there was no inter-event difference. Bradycardia was most manifest in the endurance athletes and ball game players, power athletes had higher resting heart rates than non-athletic subjects. It can be inferred that endurance training induces firstly an enlargement of the left ventricle what is then followed by an increase of muscle mass. In the studied functional and regulatory parameters no difference was found between the athletic and non-athletic groups.

  16. Gait asymmetry: composite scores for mechanical analyses of sprint running.

    PubMed

    Exell, T A; Gittoes, M J R; Irwin, G; Kerwin, D G

    2012-04-01

    Gait asymmetry analyses are beneficial from clinical, coaching and technology perspectives. Quantifying overall athlete asymmetry would be useful in allowing comparisons between participants, or between asymmetry and other factors, such as sprint running performance. The aim of this study was to develop composite kinematic and kinetic asymmetry scores to quantify athlete asymmetry during maximal speed sprint running. Eight male sprint trained athletes (age 22±5 years, mass 74.0±8.7 kg and stature 1.79±0.07 m) participated in this study. Synchronised sagittal plane kinematic and kinetic data were collected via a CODA motion analysis system, synchronised to two Kistler force plates. Bilateral, lower limb data were collected during the maximal velocity phase of sprint running (velocity=9.05±0.37 ms(-1)). Kinematic and kinetic composite asymmetry scores were developed using the previously established symmetry angle for discrete variables associated with successful sprint performance and comparisons of continuous joint power data. Unlike previous studies quantifying gait asymmetry, the scores incorporated intra-limb variability by excluding variables from the composite scores that did not display significantly larger (p<0.05) asymmetry than intra-limb variability. The variables that contributed to the composite scores and the magnitude of asymmetry observed for each measure varied on an individual participant basis. The new composite scores indicated the inter-participant differences that exist in asymmetry during sprint running and may serve to allow comparisons between overall athlete asymmetry with other important factors such as performance.

  17. Effects of sled towing on sprint starts.

    PubMed

    Cottle, Casey A; Carlson, Lara A; Lawrence, Michael A

    2014-05-01

    Sled towing is a popular method of sprint training. Researchers have struggled to identify a loading scheme that is most appropriate to improve sprint performance in the acceleration phase. The purpose of this study was to determine if loads of 10% body weight (BWT) or 20% BWT produced significantly greater propulsive ground reaction force (GRF) impulse, peak propulsive GRF, or a greater propulsive rate of force development (RFD) than an unweighted sprint start. Seventeen healthy court and field athletes (10 men, 7 women; 20.9 ± 1.1 years) completed 5 starts of each condition (unweighted, 10% BWT, 20% BWT). Participants began each start in an upright staggered stance. Propulsive GRF impulse was greater in the 20% BWT condition than the unweighted condition in both limbs and greater in the 20% BWT condition than the 10% BWT condition in the front leg only, and vertical GRF impulse was greater in the 20% BWT than the unweighted condition. In summary, our results suggest that a 10% BWT load is not sufficient to increase propulsive GRF impulse. A loading scheme of 20% BWT is sufficient to increase propulsive GRF impulse. Coaches seeking to improve sprint starts may observe improvements using a load of 20% BWT during training while towing a sled.

  18. Functional Connectivity Is Altered in Concussed Adolescent Athletes Despite Medical Clearance to Return to Play: A Preliminary Report.

    PubMed

    Newsome, Mary R; Li, Xiaoqi; Lin, Xiaodi; Wilde, Elisabeth A; Ott, Summer; Biekman, Brian; Hunter, Jill V; Dash, Pramod K; Taylor, Brian A; Levin, Harvey S

    2016-01-01

    Recovery following sports-related concussion (SRC) is slower and often more complicated in young adolescent athletes than in collegiate players. Further, the clinical decision to return to play is currently based on symptoms and cognitive performance without direct knowledge of brain function. We tested the hypothesis that brain functional connectivity (FC) would be aberrant in recently concussed, asymptomatic athletes who had been cleared to return to play. A seed-based FC analysis measured the FC of the default mode network (DMN) (seeds = anterior cingulate cortex, posterior cingulate cortex (PCC), right lateral parietal cortex, and left lateral parietal cortex) 30 days after SRC in asymptomatic high school athletes cleared to return to play (n = 13) and was compared to the FC of high school athletes with orthopedic injury (OI) (n = 13). The SRC group demonstrated greater FC than the OI group between the PCC and the ventral lateral prefrontal cortex, as well as between the right lateral parietal cortex and lateral temporal cortex (with regions both outside of and within the DMN). Additionally, the OI group demonstrated greater FC than the SRC group between right lateral parietal cortex and supramarginal gyrus. When relating the FC results to verbal memory performance approximately 1 week and 1 month after injury, significantly different between-group relations were found for the posterior cingulate and right lateral parietal cortex seeds. However, the groups did not differ in verbal memory at 1 month. We suggest that changes in FC are apparent 1-month post-SRC despite resolution of post-concussion symptoms and recovery of cognitive performance in adolescent athletes cleared to return to play. PMID:27504104

  19. Functional Connectivity Is Altered in Concussed Adolescent Athletes Despite Medical Clearance to Return to Play: A Preliminary Report

    PubMed Central

    Newsome, Mary R.; Li, Xiaoqi; Lin, Xiaodi; Wilde, Elisabeth A.; Ott, Summer; Biekman, Brian; Hunter, Jill V.; Dash, Pramod K.; Taylor, Brian A.; Levin, Harvey S.

    2016-01-01

    Recovery following sports-related concussion (SRC) is slower and often more complicated in young adolescent athletes than in collegiate players. Further, the clinical decision to return to play is currently based on symptoms and cognitive performance without direct knowledge of brain function. We tested the hypothesis that brain functional connectivity (FC) would be aberrant in recently concussed, asymptomatic athletes who had been cleared to return to play. A seed-based FC analysis measured the FC of the default mode network (DMN) (seeds = anterior cingulate cortex, posterior cingulate cortex (PCC), right lateral parietal cortex, and left lateral parietal cortex) 30 days after SRC in asymptomatic high school athletes cleared to return to play (n = 13) and was compared to the FC of high school athletes with orthopedic injury (OI) (n = 13). The SRC group demonstrated greater FC than the OI group between the PCC and the ventral lateral prefrontal cortex, as well as between the right lateral parietal cortex and lateral temporal cortex (with regions both outside of and within the DMN). Additionally, the OI group demonstrated greater FC than the SRC group between right lateral parietal cortex and supramarginal gyrus. When relating the FC results to verbal memory performance approximately 1 week and 1 month after injury, significantly different between-group relations were found for the posterior cingulate and right lateral parietal cortex seeds. However, the groups did not differ in verbal memory at 1 month. We suggest that changes in FC are apparent 1-month post-SRC despite resolution of post-concussion symptoms and recovery of cognitive performance in adolescent athletes cleared to return to play. PMID:27504104

  20. Usefulness of combined history, physical examination, electrocardiogram, and limited echocardiogram in screening adolescent athletes for risk for sudden cardiac death.

    PubMed

    Anderson, Jeffrey B; Grenier, Michelle; Edwards, Nicholas M; Madsen, Nicolas L; Czosek, Richard J; Spar, David S; Barnes, Allison; Pratt, Jesse; King, Eileen; Knilans, Timothy K

    2014-12-01

    Sudden cardiac death in the young (SCDY) is the leading cause of death in young athletes during sport. Screening young athletes for high-risk cardiac defects is controversial. The purpose of this study was to assess the utility and feasibility of a comprehensive cardiac screening protocol in an adolescent population. Adolescent athletes were recruited from local schools and/or sports teams. Each subject underwent a history and/or physical examination, an electrocardiography (ECG), and a limited echocardiography (ECHO). The primary outcome measure was identification of cardiac abnormalities associated with an elevated risk for sudden death. We secondarily identified cardiac abnormalities not typically associated with a short-term risk of sudden death. A total of 659 adolescent athletes were evaluated; 64% men. Five subjects had cardiac findings associated with an elevated risk for sudden death: prolonged QTc >500 ms (n = 2) and type I Brugada pattern (n = 1), identified with ECG; dilated cardiomyopathy (n = 1) and significant aortic root dilation; and z-score = +5.5 (n = 1). History and physical examination alone identified 76 (11.5%) subjects with any cardiac findings. ECG identified 76 (11.5%) subjects in which a follow-up ECHO or cardiology visit was recommended. Left ventricular mass was normal by ECHO in all but 1 patient with LVH on ECG. ECHO identified 34 (5.1%) subjects in whom a follow-up ECHO or cardiology visit was recommended. In conclusion, physical examination alone was ineffective in identification of subjects at elevated risk for SCDY. Screening ECHO identified patients with underlying cardiac disease not associated with immediate risk for SCDY. Cost of comprehensive cardiac screening is high.

  1. The child and adolescent athlete: a review of three potentially serious injuries.

    PubMed

    Caine, Dennis; Purcell, Laura; Maffulli, Nicola

    2014-01-01

    The increased participation of children and adolescents in organized sports worldwide is a welcome trend given evidence of lower physical fitness and increased prevalence of overweight in this population. However, the increased sports activity of children from an early age and continued through the years of growth, against a background of their unique vulnerability to injury, gives rise to concern about the risk and severity of injury. Three types of injury-anterior cruciate ligament (ACL) injury, concussion, and physeal injury - are considered potentially serious given their frequency, potential for adverse long-term health outcomes, and escalating healthcare costs. Concussion is probably the hottest topic in sports injury currently with voracious media coverage and exploding research interest. Given the negative cognitive effects of concussion, it has the potential to have a great impact on children and adolescents during their formative years and potentially impair school achievement and, if concussion management is not managed appropriately, there can be long term negative impact on cognitive development and ability to resume sports participation. Sudden and gradual onset physeal injury is a unique injury to the pediatric population which can adversely affect growth if not managed correctly. Although data are lacking, the frequency of stress-related physeal injury appears to be increasing. If mismanaged, physeal injuries can also lead to long-term complications which could negatively affect ability to participate in sports. Management of ACL injuries is an area of controversy and if not managed appropriately, can affect long-term growth and recovery as well as the ability to participate in sports. This article considers the young athlete's vulnerability to injury, with special reference to ACL injury, concussion, and physeal injury, and reviews current research on epidemiology, diagnosis, treatment, and prevention of these injury types. This article is intended

  2. Characterization of the Sprint and Repeated-Sprint Sequences Performed by Professional Futsal Players, According to Playing Position, During Official Matches.

    PubMed

    Caetano, Fabio Giuliano; de Oliveira Bueno, Murilo José; de Oliveira, Murilo José; Marche, Ana Lorena; Nakamura, Fábio Yuzo; Cunha, Sergio Augusto; Moura, Felipe Arruda

    2015-12-01

    The purposes of this study were to investigate sprints and to characterize repeated-sprint sequences (RS) performed by athletes during professional futsal matches. We analyzed 97 players during 5 official matches using the DVideo automatic tracking system. The sprints were analyzed during the first and second halves according to playing position, and RS were categorized according to the number of sprints and the time between them. The results showed an increase (F[1, 2520] = 3.96; P = .046) in the sprint duration from the first (mean = 3.1 ± 1.3) to the second half (mean = 3.2 ± 1.2). However, no differences were found for other variables (distance covered, peak velocity, initial velocity, recovery time between sprints, and sprints performed per minute) or among playing positions. In addition, when considering RS, the results showed that RS comprising two sprints interspersed with a maximum of 15 seconds of recovery were significantly more frequent than other RS. The findings of this study characterizing the sprinting features of futsal players can help coaches to plan physical training and assessments according to the requirements of the sport. PMID:26155741

  3. Comparison of the short-term oxidative stress response in National League basketball and soccer adolescent athletes.

    PubMed

    Perrea, Anastasia; Vlachos, Ioannis S; Korou, Laskarina-Maria; Doulamis, Ilias P; Exarhopoulou, Konstantina; Kypraios, George; Kalofoutis, Anastasios; Perrea, Despina N

    2014-08-01

    Physical exercise is considered protective against oxidative stress-related disorders. However, there is increasing evidence that strenuous activity may induce increased oxidative stress response. This study investigated the impact of vigorous physical activity on serum oxidative stress markers in 36 soccer and 12 basketball National League adolescent athletes 40 minutes before and 15 minutes after a National League game. Serum total peroxide, fibrinogen, polymorphonuclear (PMN) elastase, and myeloperoxidase levels were determined. No significant differences in any of the measured parameters were observed before the match. Soccer players exhibited significantly lower total peroxide (P < .05) and higher PMN elastase concentrations (P < .05) than that of the basketball athletes after the game. A number of important differences between these 2 sports, such as duration or total aerobic and anaerobic demands, may affect oxidative status. These parameters need to be further examined in order to elucidate the different effects of these 2 sports on postexercise oxidative status.

  4. [A pilot study on adolescents of both sexes. Correlation between phenotype, athletic performances and family history to type 2 diabetes].

    PubMed

    Pomara, F; Grosso, F; Basile, D; Polizzi, V; Marcianò, C; Adamo, V; De Vita, A; Petrucci, M

    2010-10-01

    The authors have studied the influence of family history of type 2 diabetes on the physical phenotype of 47 health adolescents. In both sexes groups with positive family history (FH+) had the highest values of stature and body weight (P<0.05 for males, not significant for females), waist circumference (P<0.05 for males, not significant for females), and wrist circumference (P=0.05 for males, not significant for females). Considering athletic performance, FH+ males showed a significant higher performance in power exercises than FH- males; no significant differences were found between FH+ and FH- female groups. The study confirms that family history of type 2 diabetes can induce in both sexes precocious phenotype and athletic performances linked-related variations; larger studies are necessary to confirm these data and to verify preventive interventions promoting significant life-style changes. PMID:20940677

  5. Postactivation potentiation of sprint acceleration performance using plyometric exercise.

    PubMed

    Turner, Anthony P; Bellhouse, Sam; Kilduff, Liam P; Russell, Mark

    2015-02-01

    Postactivation potentiation (PAP), an acute and temporary enhancement of muscular performance resulting from previous muscular contraction, commonly occurs after heavy resistance exercise. However, this method of inducing PAP has limited application to the precompetition practices (e.g., warm-up) of many athletes. Very few studies have examined the influence of plyometric activity on subsequent performance; therefore, we aimed to examine the influence of alternate-leg bounding on sprint acceleration performance. In a randomized crossover manner, plyometric-trained men (n = 23) performed seven 20-m sprints (with 10-m splits) at baseline, ∼15 seconds, 2, 4, 8, 12, and 16 minutes after a walking control (C) or 3 sets of 10 repetitions of alternate-leg bounding using body mass (plyometric, P) and body mass plus 10% (weighted plyometric, WP). Mean sprint velocities over 10 and 20 m were similar between trials at baseline. At ∼15 seconds, WP impaired 20-m sprint velocity by 1.4 ± 2.5% when compared with C (p = 0.039). Thereafter, 10- and 20-m sprint velocities improved in WP at 4 minutes (10 m: 2.2 ± 3.1%, p = 0.009; 20 m: 2.3 ± 2.6%, p = 0.001) and 8 minutes (10 m: 2.9 ± 3.6%, p = 0.002; 20 m: 2.6 ± 2.8%, p = 0.001) compared with C. Improved 10-m sprint acceleration performance occurred in P at 4 minutes (1.8 ± 3.3%, p = 0.047) relative to C. Therefore, sprint acceleration performance is enhanced after plyometric exercise providing adequate recovery is given between these activities; however, the effects may differ according to whether additional load is applied. This finding presents a practical method to enhance the precompetition practices of athletes.

  6. Comparing sports vision among three groups of soft tennis adolescent athletes: Normal vision, refractive errors with and without correction

    PubMed Central

    Chang, Shih-Tsun; Liu, Yen-Hsiu; Lee, Jiahn-Shing; See, Lai-Chu

    2015-01-01

    Background: The effect of correcting static vision on sports vision is still not clear. Aim: To examine whether sports vision (depth perception [DP], dynamic visual acuity [DVA], eye movement [EM], peripheral vision [PV], and momentary vision [MV],) were different among soft tennis adolescent athletes with normal vision (Group A), with refractive error and corrected with (Group B) and without eyeglasses (Group C). Setting and Design: A cross-section study was conducted. Soft tennis athletes aged 10–13 who played softball tennis for 2–5 years, and who were without any ocular diseases and without visual training for the past 3 months were recruited. Materials and Methods: DPs were measured in an absolute deviation (mm) between a moving rod and fixing rod (approaching at 25 mm/s, receding at 25 mm/s, approaching at 50 mm/s, receding at 50 mm/s) using electric DP tester. A smaller deviation represented better DP. DVA, EM, PV, and MV were measured on a scale from 1 (worse) to 10 (best) using ATHLEVISION software. Statistical Analysis: Chi-square test and Kruskal–Wallis test was used to compare the data among the three study groups. Results: A total of 73 athletes (37 in Group A, 8 in Group B, 28 in Group C) were enrolled in this study. All four items of DP showed significant difference among the three study groups (P = 0.0051, 0.0004, 0.0095, 0.0021). PV displayed significant difference among the three study groups (P = 0.0044). There was no significant difference in DVA, EM, and MV among the three study groups. Conclusions: Significant better DP and PV were seen among soft tennis adolescent athletes with normal vision than those with refractive error regardless whether they had eyeglasses corrected. On the other hand, DVA, EM, and MV were similar among the three study groups. PMID:26632127

  7. A displaced stress fracture of the femoral neck in an adolescent female distance runner with female athlete triad: A case report.

    PubMed

    Okamoto, Shinichi; Arai, Yuji; Hara, Kunio; Tsuzihara, Takashi; Kubo, Toshikazu

    2010-01-01

    This report presents a case of a displaced stress fracture of the femoral neck in an adolescent female distance runner with amenorrhea. Both reduction and internal fixation were performed early after the injury. At 24 months postoperatively, magnetic resonance imaging and bone scintigraphy showed no positive signs of femoral head necrosis and bone union was confirmed on plain X-ray. A medical examination for the presence of the signs of the female athlete triad by checking weight, calorie intake and menstrual cycles is most important to prevent such stress fractures. Athletes as well as their coaches or parents therefore need to understand female athlete triad. PMID:20205723

  8. No Additional Benefit of Repeat-Sprint Training in Hypoxia than in Normoxia on Sea-Level Repeat-Sprint Ability

    PubMed Central

    Goods, Paul S.R.; Dawson, Brian; Landers, Grant J.; Gore, Christopher J.; Peeling, Peter

    2015-01-01

    To assess the impact of ‘top-up’ normoxic or hypoxic repeat-sprint training on sea-level repeat-sprint ability, thirty team sport athletes were randomly split into three groups, which were matched in running repeat-sprint ability (RSA), cycling RSA and 20 m shuttle run performance. Two groups then performed 15 maximal cycling repeat-sprint training sessions over 5 weeks, in either normoxia (NORM) or hypoxia (HYP), while a third group acted as a control (CON). In the post-training cycling RSA test, both NORM (13.6%; p = 0.0001, and 8.6%; p = 0.001) and HYP (10.3%; p = 0.007, and 4.7%; p = 0.046) significantly improved overall mean and peak power output, respectively, whereas CON did not change (1.4%; p = 0.528, and -1.1%; p = 0.571, respectively); with only NORM demonstrating a moderate effect for improved mean and peak power output compared to CON. Running RSA demonstrated no significant between group differences; however, the mean sprint times improved significantly from pre- to post-training for CON (1.1%), NORM (1.8%), and HYP (2.3%). Finally, there were no group differences in 20 m shuttle run performance. In conclusion, ‘top-up’ training improved performance in a task-specific activity (i.e. cycling); however, there was no additional benefit of conducting this ‘top-up’ training in hypoxia, since cycle RSA improved similarly in both HYP and NORM conditions. Regardless, the ‘top-up’ training had no significant impact on running RSA, therefore the use of cycle repeat-sprint training should be discouraged for team sport athletes due to limitations in specificity. Key points ‘Top-up’ repeat-sprint training performed on a cycle ergometer enhances cycle repeat-sprint ability compared to team sport training only in football players. The addition of moderate hypoxia to repeat-sprint training provides no additional performance benefits to sea-level repeat-sprint ability or endurance performance than normoxic repeat-sprint training.

  9. No Additional Benefit of Repeat-Sprint Training in Hypoxia than in Normoxia on Sea-Level Repeat-Sprint Ability.

    PubMed

    Goods, Paul S R; Dawson, Brian; Landers, Grant J; Gore, Christopher J; Peeling, Peter

    2015-09-01

    To assess the impact of 'top-up' normoxic or hypoxic repeat-sprint training on sea-level repeat-sprint ability, thirty team sport athletes were randomly split into three groups, which were matched in running repeat-sprint ability (RSA), cycling RSA and 20 m shuttle run performance. Two groups then performed 15 maximal cycling repeat-sprint training sessions over 5 weeks, in either normoxia (NORM) or hypoxia (HYP), while a third group acted as a control (CON). In the post-training cycling RSA test, both NORM (13.6%; p = 0.0001, and 8.6%; p = 0.001) and HYP (10.3%; p = 0.007, and 4.7%; p = 0.046) significantly improved overall mean and peak power output, respectively, whereas CON did not change (1.4%; p = 0.528, and -1.1%; p = 0.571, respectively); with only NORM demonstrating a moderate effect for improved mean and peak power output compared to CON. Running RSA demonstrated no significant between group differences; however, the mean sprint times improved significantly from pre- to post-training for CON (1.1%), NORM (1.8%), and HYP (2.3%). Finally, there were no group differences in 20 m shuttle run performance. In conclusion, 'top-up' training improved performance in a task-specific activity (i.e. cycling); however, there was no additional benefit of conducting this 'top-up' training in hypoxia, since cycle RSA improved similarly in both HYP and NORM conditions. Regardless, the 'top-up' training had no significant impact on running RSA, therefore the use of cycle repeat-sprint training should be discouraged for team sport athletes due to limitations in specificity. Key points'Top-up' repeat-sprint training performed on a cycle ergometer enhances cycle repeat-sprint ability compared to team sport training only in football players.The addition of moderate hypoxia to repeat-sprint training provides no additional performance benefits to sea-level repeat-sprint ability or endurance performance than normoxic repeat-sprint training.'Top-up' cycling repeat-sprint training

  10. Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating.

    PubMed

    Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

    2016-03-01

    The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs) were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour) for 8 weeks. Training intensity was determined within non-specific (cycling or running) and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m) and one non-specific (30s cycling or 200m running) all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa) and glucose (BGL) 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak) was significantly increased (+17%; p = 0.01) in both groups and highly correlated with the sprint performance (r = -0.71). BLa values decreased significantly (-18%, p = 0.02) after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04) in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group. Key pointsIn addition to a highly developed aerobic performance inline speed skaters also require a highly trained anaerobic capacity to be effective in the sprint sections such as the mass start, tactical attacks

  11. Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

    PubMed Central

    Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K.

    2016-01-01

    The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs) were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour) for 8 weeks. Training intensity was determined within non-specific (cycling or running) and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m) and one non-specific (30s cycling or 200m running) all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa) and glucose (BGL) 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak) was significantly increased (+17%; p = 0.01) in both groups and highly correlated with the sprint performance (r = -0.71). BLa values decreased significantly (-18%, p = 0.02) after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04) in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group. Key points In addition to a highly developed aerobic performance inline speed skaters also require a highly trained anaerobic capacity to be effective in the sprint sections such as the mass start, tactical attacks

  12. Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating.

    PubMed

    Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

    2016-03-01

    The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs) were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour) for 8 weeks. Training intensity was determined within non-specific (cycling or running) and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m) and one non-specific (30s cycling or 200m running) all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa) and glucose (BGL) 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak) was significantly increased (+17%; p = 0.01) in both groups and highly correlated with the sprint performance (r = -0.71). BLa values decreased significantly (-18%, p = 0.02) after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04) in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group. Key pointsIn addition to a highly developed aerobic performance inline speed skaters also require a highly trained anaerobic capacity to be effective in the sprint sections such as the mass start, tactical attacks

  13. Repeated-sprint ability - part I: factors contributing to fatigue.

    PubMed

    Girard, Olivier; Mendez-Villanueva, Alberto; Bishop, David

    2011-08-01

    Short-duration sprints (<10 seconds), interspersed with brief recoveries (<60 seconds), are common during most team and racket sports. Therefore, the ability to recover and to reproduce performance in subsequent sprints is probably an important fitness requirement of athletes engaged in these disciplines, and has been termed repeated-sprint ability (RSA). This review (Part I) examines how fatigue manifests during repeated-sprint exercise (RSE), and discusses the potential underpinning muscular and neural mechanisms. A subsequent companion review to this article will explain a better understanding of the training interventions that could eventually improve RSA. Using laboratory and field-based protocols, performance analyses have consistently shown that fatigue during RSE typically manifests as a decline in maximal/mean sprint speed (i.e. running) or a decrease in peak power or total work (i.e. cycling) over sprint repetitions. A consistent result among these studies is that performance decrements (i.e. fatigue) during successive bouts are inversely correlated to initial sprint performance. To date, there is no doubt that the details of the task (e.g. changes in the nature of the work/recovery bouts) alter the time course/magnitude of fatigue development during RSE (i.e. task dependency) and potentially the contribution of the underlying mechanisms. At the muscle level, limitations in energy supply, which include energy available from phosphocreatine hydrolysis, anaerobic glycolysis and oxidative metabolism, and the intramuscular accumulation of metabolic by-products, such as hydrogen ions, emerge as key factors responsible for fatigue. Although not as extensively studied, the use of surface electromyography techniques has revealed that failure to fully activate the contracting musculature and/or changes in inter-muscle recruitment strategies (i.e. neural factors) are also associated with fatigue outcomes. Pending confirmatory research, other factors such as

  14. Individual and relational risk factors for the development of eating disorders in adolescent aesthetic athletes and general adolescents.

    PubMed

    Francisco, Rita; Narciso, Isabel; Alarcão, Madalena

    2013-12-01

    This study compared potential risk and protective factors, levels of disordered eating (DE), and their relationship among young aesthetic athletes (elite and non-elite) and controls (N = 725; 62.5 % females; mean age = 15.3, SD = 2.1). The participants completed self-report measures (McKnight Risk Factor Survey-IV, Contour Drawing Rating Scale and Eating Disorder Examination-Questionnaire). Female elite athletes showed a greater risk of developing eating disorders than non-elite athletes and controls, with no difference between the three groups of males. Multiple group analyses revealed important differences in DE predictors. Although social pressure is the strongest DE predictor in non-elite athletes and controls, in elite athletes, the strongest DE predictor is body image dissatisfaction. Parental influences, rather than self-esteem, are predictors of DE in elite athletes, unlike the other two groups. These results show that the risk and protective factors involved in the development of DE are not universally valid. The results highlight the importance of studying specific characteristics associated with DE in aesthetic athletes. Some implications for ED risk assessment and prevention are discussed.

  15. Individual and relational risk factors for the development of eating disorders in adolescent aesthetic athletes and general adolescents.

    PubMed

    Francisco, Rita; Narciso, Isabel; Alarcão, Madalena

    2013-12-01

    This study compared potential risk and protective factors, levels of disordered eating (DE), and their relationship among young aesthetic athletes (elite and non-elite) and controls (N = 725; 62.5 % females; mean age = 15.3, SD = 2.1). The participants completed self-report measures (McKnight Risk Factor Survey-IV, Contour Drawing Rating Scale and Eating Disorder Examination-Questionnaire). Female elite athletes showed a greater risk of developing eating disorders than non-elite athletes and controls, with no difference between the three groups of males. Multiple group analyses revealed important differences in DE predictors. Although social pressure is the strongest DE predictor in non-elite athletes and controls, in elite athletes, the strongest DE predictor is body image dissatisfaction. Parental influences, rather than self-esteem, are predictors of DE in elite athletes, unlike the other two groups. These results show that the risk and protective factors involved in the development of DE are not universally valid. The results highlight the importance of studying specific characteristics associated with DE in aesthetic athletes. Some implications for ED risk assessment and prevention are discussed. PMID:23943379

  16. Integrative training for children and adolescents: techniques and practices for reducing sports-related injuries and enhancing athletic performance.

    PubMed

    Myer, Gregory D; Faigenbaum, Avery D; Chu, Donald A; Falkel, Jeff; Ford, Kevin R; Best, Thomas M; Hewett, Timothy E

    2011-02-01

    As more children and adolescents participate in sports and conditioning activities (sometimes without consideration for cumulative workload), it is important to establish age-appropriate training guidelines that may reduce the risk of sports-related injury and enhance athletic performance. The purpose of this article is to review the scientific evidence on youth strength and conditioning and to provide age-appropriate recommendations for integrating different strength and conditioning activities into a well-designed program that is safe, effective, and enjoyable. Integrative training is defined as a program or plan that incorporates general and specific strength and conditioning activities that enhance both health- and skill-related components of physical fitness. The cornerstone of integrative training is age-appropriate education and instruction by qualified professionals who understand the physical and psychosocial uniqueness of children and adolescents.

  17. Total haemoglobin mass and red blood cell profile in endurance-trained and non-endurance-trained adolescent athletes.

    PubMed

    Ulrich, Gert; Bärtsch, Peter; Friedmann-Bette, Birgit

    2011-11-01

    To evaluate differences in total haemoglobin mass (tHb mass) and in red blood cell profile between elite endurance-trained (END) and non-endurance-trained (nEND) male and female adolescent athletes, tHb mass (CO rebreathing) and specific variables of red blood cell profile (haemoglobin concentration, haematocrit, erythrocyte indices) were determined in 59 elite junior athletes (29 END, 30 nEND). We hypothesized that at the age of 15-17 years, regular endurance training might induce a significant increase in tHb mass and changes in red blood cell profile. Therefore, all parameters were again determined after 6, 12 and 18 months in a subset of 27 subjects (17 END, 10 nEND). In END, tHb mass related to body weight was ~15% greater than in nEND (11.2 ± 1.6  vs. 9.7 ± 1.3 g kg(-1), P < 0.001), whereas no significant differences were observed for the red blood cell profile. In both groups, tHb mass related to body weight and the variables of red blood cell profile had not changed significantly after 6, 12 and 18 months of regular training. In conclusion, in elite junior athletes, differences in tHb mass between END and nEND were similar, however, smaller compared with previously in adult athletes reported values. At the age of 15-17 years, 18 months of regular training did not induce significant changes in tHb mass beyond alterations explained by physical growth and also variables of red blood cell profile did not change significantly.

  18. Effect of the coefficient of friction of a running surface on sprint time in a sled-towing exercise.

    PubMed

    Linthorne, Nicholas P; Cooper, James E

    2013-06-01

    This study investigated the effect of the coefficient of friction of a running surface on an athlete's sprint time in a sled-towing exercise. The coefficients of friction of four common sports surfaces (a synthetic athletics track, a natural grass rugby pitch, a 3G football pitch, and an artificial grass hockey pitch) were determined from the force required to tow a weighted sled across the surface. Timing gates were then used to measure the 30-m sprint time for six rugby players when towing a sled of varied weight across the surfaces. There were substantial differences between the coefficients of friction for the four surfaces (micro = 0.21-0.58), and in the sled-towing exercise the athlete's 30-m sprint time increased linearly with increasing sled weight. The hockey pitch (which had the lowest coefficient of friction) produced a substantially lower rate of increase in 30-m sprint time, but there were no significant differences between the other surfaces. The results indicate that although an athlete's sprint time in a sled-towing exercise is affected by the coefficient offriction of the surface, the relationship relationship between the athlete's rate of increase in 30-m sprint time and the coefficient of friction is more complex than expected.

  19. Sprinting performance and resistance-based training interventions: a systematic review.

    PubMed

    Bolger, Richard; Lyons, Mark; Harrison, Andrew J; Kenny, Ian C

    2015-04-01

    The purpose of this systematic review was to search the scientific literature for original research, addressing the effects different forms of resistance-based training have on sprinting performance in competitive sprinters. Specific key words (Sprinters OR Sprint) NOT (Rugby, Soccer, Cycling, Swimming, Paralympic, and Nutrition) were used to search relevant databases through November 2013 for related literature. Original research was reviewed using the Physiotherapy Evidence Database scale. Five studies met the inclusion criteria: actively competitive adult male sprinters who participated in a resistance-based intervention (>4 weeks), with outcome measures in the form of 10- to 100-m sprint times. Exclusion criteria included acute studies (<4 weeks), nonsprinting populations, and studies with no performance outcome measures (10- to 100-m sprint times). Three of the 5 studies used both locomotor resistance and fixed plane resistance, whereas the remaining 2 studies used more fixed plane resistance, for example, squat and leg extension. Three of the studies showed a statistical improvement in sprinting performance measures, for example, a decrease in 30-m sprint time (p = 0.044), whereas 1 study showed a decrease in sprinting performance. The analysis concluded that resistance-based training has a positive effect on sprinting performance. Varied input of locomotor resistance and fixed plane resistance has resulted in similar percentage change for sprinting performance. This review adds to the body of knowledge by strongly highlighting the dearth of literature exploring the effects of resistance-based training on sprinting performance in competitive sprinters. The short duration and wide range of exercises implemented in studies to date are of concern, but coaches should not hesitate to implement well-planned resistance programs for their sprint athletes. PMID:25268287

  20. Sprinting performance and resistance-based training interventions: a systematic review.

    PubMed

    Bolger, Richard; Lyons, Mark; Harrison, Andrew J; Kenny, Ian C

    2015-04-01

    The purpose of this systematic review was to search the scientific literature for original research, addressing the effects different forms of resistance-based training have on sprinting performance in competitive sprinters. Specific key words (Sprinters OR Sprint) NOT (Rugby, Soccer, Cycling, Swimming, Paralympic, and Nutrition) were used to search relevant databases through November 2013 for related literature. Original research was reviewed using the Physiotherapy Evidence Database scale. Five studies met the inclusion criteria: actively competitive adult male sprinters who participated in a resistance-based intervention (>4 weeks), with outcome measures in the form of 10- to 100-m sprint times. Exclusion criteria included acute studies (<4 weeks), nonsprinting populations, and studies with no performance outcome measures (10- to 100-m sprint times). Three of the 5 studies used both locomotor resistance and fixed plane resistance, whereas the remaining 2 studies used more fixed plane resistance, for example, squat and leg extension. Three of the studies showed a statistical improvement in sprinting performance measures, for example, a decrease in 30-m sprint time (p = 0.044), whereas 1 study showed a decrease in sprinting performance. The analysis concluded that resistance-based training has a positive effect on sprinting performance. Varied input of locomotor resistance and fixed plane resistance has resulted in similar percentage change for sprinting performance. This review adds to the body of knowledge by strongly highlighting the dearth of literature exploring the effects of resistance-based training on sprinting performance in competitive sprinters. The short duration and wide range of exercises implemented in studies to date are of concern, but coaches should not hesitate to implement well-planned resistance programs for their sprint athletes.

  1. Physics of Sprinting.

    ERIC Educational Resources Information Center

    Alexandrov, Igor; Lucht, Phillip

    1981-01-01

    Sprinting is described by a simple physical model. The model is used to predict the differences between the recorded times for races on a straight track and on a curve. It is shown that the choice of the running lane makes a nonnegligible difference. (Author/SK)

  2. [Sports and adolescence: the effect of competitive athletics on menstrual function].

    PubMed

    Trivelli, M R; Biglia, C; Castagno, A; Chiara, G

    1995-04-01

    A group of 381 girls, 12 up to 19-years-old, engaging in competitive sports (athletics, basketball, dancing, gymnastics, swimming, ski-ing, tennis, volley-ball) was examined. Age at menarche and menstrual characteristics were correlated with the body weight, the competitive practice start age, the kind of the sport and the amount of training hours/week. Collected data were compared with the ones from a pool of 387 girls of equivalent mean age, not playing any sport. Delay of menarche and larger frequency of menstrual disorders, found among athletes, turned out to be directly proportional to the amount of time devoted to training and to the kind of performed sports. Irregular cycles are more frequent in athletes having a normal or lower body weight and do not normalise proceeding in sporting activities.

  3. A Commentary on Real-Time Biofeedback to Augment Neuromuscular Training for ACL Injury Prevention in Adolescent Athletes

    PubMed Central

    Kiefer, Adam W.; Kushner, Adam M.; Groene, John; Williams, Christopher; Riley, Michael A.; Myer, Gregory D.

    2015-01-01

    Anterior cruciate ligament injury and the associated long-term sequelae, such as immediate reductions in physical inactivity, increased adiposity and increased risk of osteoarthritis throughout adulthood, are a major health concern for adolescent athletes. Current interventions for injury prevention may have limited effectiveness, are susceptible to issues of compliance and have not achieved the widespread acceptance necessary to promote full adoption. Neuromuscular training (NMT) is a well-established training intervention introduced to affect change in modifiable biomechanical risk factors to reduce the risk of injury in these athletes. Despite moderate success, neuromuscular training is still limited by its reliance on subjective feedback and after the fact (i.e., offline) objective feedback techniques. The purpose of this commentary is to discuss technological tools that could be used to enhance and objectify targeted biofeedback interventions to complement NMT. Electromyography, force plates, motion sensors, and camera-based motion capture systems are innovative tools that may have realistic feasibility for integration as biofeedback into NMT programs to improve training outcomes. Improved functional deficit identification and corrective analysis may further improve and optimize athletic performance, and decrease the risk of sports-related injury during sport performance. Key points Specific, targeted interventions that isolate injury risk factors and can help correct modifiable neuromuscular deficits are essential. Current training interventions for anterior cruciate ligament (ACL) injury prevention have only demonstrated limited effectiveness and have not achieved the widespread acceptance necessary to promote full adoption to reduce ACL injury rates. The paper provides an overview of innovative strategies and technological tools that could be used to enhance and objectify targeted biofeedback interventions to complement neuromuscular training (NMT

  4. A Commentary on Real-Time Biofeedback to Augment Neuromuscular Training for ACL Injury Prevention in Adolescent Athletes.

    PubMed

    Kiefer, Adam W; Kushner, Adam M; Groene, John; Williams, Christopher; Riley, Michael A; Myer, Gregory D

    2015-03-01

    Anterior cruciate ligament injury and the associated long-term sequelae, such as immediate reductions in physical inactivity, increased adiposity and increased risk of osteoarthritis throughout adulthood, are a major health concern for adolescent athletes. Current interventions for injury prevention may have limited effectiveness, are susceptible to issues of compliance and have not achieved the widespread acceptance necessary to promote full adoption. Neuromuscular training (NMT) is a well-established training intervention introduced to affect change in modifiable biomechanical risk factors to reduce the risk of injury in these athletes. Despite moderate success, neuromuscular training is still limited by its reliance on subjective feedback and after the fact (i.e., offline) objective feedback techniques. The purpose of this commentary is to discuss technological tools that could be used to enhance and objectify targeted biofeedback interventions to complement NMT. Electromyography, force plates, motion sensors, and camera-based motion capture systems are innovative tools that may have realistic feasibility for integration as biofeedback into NMT programs to improve training outcomes. Improved functional deficit identification and corrective analysis may further improve and optimize athletic performance, and decrease the risk of sports-related injury during sport performance. Key pointsSpecific, targeted interventions that isolate injury risk factors and can help correct modifiable neuromuscular deficits are essential.Current training interventions for anterior cruciate ligament (ACL) injury prevention have only demonstrated limited effectiveness and have not achieved the widespread acceptance necessary to promote full adoption to reduce ACL injury rates.The paper provides an overview of innovative strategies and technological tools that could be used to enhance and objectify targeted biofeedback interventions to complement neuromuscular training (NMT) including

  5. Hip Structural Analysis in Adolescent and Young Adult Oligoamenorrheic and Eumenorrheic Athletes and Nonathletes

    PubMed Central

    Ackerman, Kathryn E.; Pierce, Lisa; Guereca, Gabriela; Slattery, Meghan; Lee, Hang; Goldstein, Mark

    2013-01-01

    Context: Stress fractures are common in endurance athletes. Whereas studies have described distal tibia bone structure in athletes, there are few data regarding hip geometric parameters. Hip structural analysis (HSA) using dual-energy x-ray absorptiometry is a validated technique to assess hip bone structure. Objectives: The purpose of this study was to compare hip geometry in young oligoamenorrheic athletes (AAs), eumenorrheic athletes (EAs), and nonathletes using HSA. We hypothesized that AAs would have impaired bone structure compared with that of EAs. Design: This was a cross-sectional study. Setting: The setting was a clinical research center. Subjects: We enrolled 55 AAs, 24 EAs, and 23 nonathletes of normal weight who were 14 to 22 years old. Athletes ran ≥20 miles/wk or were engaged in weight-bearing sports for ≥4 hours/wk. Main Outcome Measures: Dual-energy x-ray absorptiometry was used for HSA and hip areal bone mineral density (aBMD). Results: Hip aBMD Z-scores were lower in AAs and in nonathletes than in EAs (P = .002). A larger proportion of AAs than EAs and nonathletes had hip Z-scores <−1 (30.9, 4.2, 17.4%, P = .01). At the narrow neck, trochanteric region, and femoral shaft, subperiosteal width, cross-sectional moment of inertia, and section modulus were higher in EAs than in nonathletes; values in AAs did not differ from those of nonathletes. Cross-sectional area was lower in AAs and in nonathletes than in EAs. Groups did not differ for cortical thickness or buckling ratio. Group differences were lost after adjustment for lean mass but not aBMD. Conclusions: In an eugonadal state, athletic activity confers benefits for hip structure independent of aBMD. This advantage is lost in AAs, who do not differ from nonathletes for most parameters and fare worse than EAs for cross-sectional area. PMID:23476076

  6. Expert opinion and controversies in sports and musculoskeletal medicine: the diagnosis and treatment of spondylolysis in adolescent athletes.

    PubMed

    Standaert, Christopher J; Herring, Stanley A

    2007-04-01

    Although spondylolysis is relatively common in adolescent athletes, there are substantial disagreements in the literature concerning the best methods for diagnosing and treating the condition. Controversy particularly arises regarding the optimal use of available imaging modalities in the diagnosis of athletes with suspected pars defects and the extent of activity restriction or brace use required for appropriate treatment. Because there have been no controlled trials on the treatment of spondylolysis and only a very limited number of studies addressing potential imaging strategies, it is difficult to develop true evidence-based guidelines for this condition. Given the current state of the literature, it is our impression that nuclear imaging with single photon emission computed tomography followed by computed tomography, with a limited role for plain radiography, remains the standard for appropriately diagnosing a symptomatic pars lesion. Treatment hinges on activity restriction for an amount of time adequate to allow for symptom resolution and, when possible, potential bony healing followed by a progressive sport-specific rehabilitation program. The biomechanic effects of brace use in this population are not well understood, but there may be some detrimental effects to the use of a brace and there currently is no evidence that the routine use of a rigid brace results in any significant improvement in radiographic or functional outcome. PMID:17398258

  7. Female Athlete Triad

    MedlinePlus

    ... pediatricians and adolescent medicine specialists, sports medicine doctors, nutritionists and dietitians, and mental health specialists can all ... granola bars, and fruit. Visit a dietitian or nutritionist who works with teen athletes. He or she ...

  8. Appropriate Loads for Peak-Power During Resisted Sprinting on a Non-Motorized Treadmill

    PubMed Central

    Andre, Matthew J.; Fry, Andrew C.; Lane, Michael T.

    2013-01-01

    The purpose of this study was to determine the load which allows the highest peak power for resisted sprinting on a non-motorized treadmill and to determine if other variables are related to individual differences. Thirty college students were tested for vertical jump, vertical jump peak and mean power, 10 m sprint, 20 m sprint, leg press 1 RM, leg press 1 RM relative to body weight, leg press 1 RM relative to lean body mass, leg press 1 RM power, and leg press power at 80% of 1 RM. Participants performed eight resisted sprints on a non-motorized treadmill, with increasing relative loads expressed as percent of body weight. Sprint peak power was measured for each load. Pearson correlations were used to determine if relationships between the sprint peak power load and the other variables were significant. The sprint peak power load had a mode of 35% with 73% of all participants having a relative sprint peak power load between 25–35%. Significant correlations occurred between sprint peak power load and body weight, lean body mass, vertical jump peak and mean power, leg press 1 RM, leg press 1 RM relative to lean body mass, leg press 1 RM power, and leg press power at 80% of 1 RM (r = 0.44, 0.43, 0.39, 0.37, 0.47, 0.39, 0.46, and 0.47, respectively). Larger, stronger, more powerful athletes produced peak power at a higher relative load during resisted sprinting on a non-motorized treadmill. PMID:24233103

  9. Effects of weighted sled towing with heavy versus light load on sprint acceleration ability.

    PubMed

    Kawamori, Naoki; Newton, Robert U; Hori, Naruhiro; Nosaka, Kazunori

    2014-10-01

    Weighted sled towing is used by athletes to improve sprint acceleration ability. The typical coaching recommendation is to use relatively light loads, as excessively heavy loads are hypothesized to disrupt running mechanics and be detrimental to sprint performance. However, this coaching recommendation has not been empirically tested. This study compared the effects of weighted sled towing with 2 different external loads on sprint acceleration ability. Twenty-one physically active men were randomly allocated to heavy- (n = 10) or light-load weighted sled towing (n = 11) groups. All subjects participated in 2 training sessions per week for 8 weeks. The subjects in the heavy and light groups performed weighted sled towing using external loads that reduced sprint velocity by approximately 30 and 10%, respectively. Before and after the training, the subjects performed a 10-m sprint test, in which split time was measured at 5 and 10 m from the start. The heavy group significantly improved both the 5- and 10-m sprint time by 5.7 ± 5.7 and 5.0 ± 3.5%, respectively (P < 0.05), whereas only 10-m sprint time was improved significantly by 3.0 ± 3.5% (P < 0.05) in the light group. No significant differences were found between the groups in the changes in 5-m and 10-m sprint time from pre- to posttraining. These results question the notion that training loads that induce greater than 10% reduction in sprint velocity would negatively affect sprint performance and point out the potential benefit of using a heavier load for weighted sled towing.

  10. Selected determinants of acceleration in the 100m sprint.

    PubMed

    Maćkała, Krzysztof; Fostiak, Marek; Kowalski, Kacper

    2015-03-29

    The goal of this study was to examine the relationship between kinematics, motor abilities, anthropometric characteristics, and the initial (10 m) and secondary (30 m) acceleration phases of the 100 m sprint among athletes of different sprinting performances. Eleven competitive male sprinters (10.96 s ± 0.36 for 100 with 10.50 s fastest time) and 11 active students (12.20 s ± 0.39 for 100 m with 11.80 s fastest time) volunteered to participate in this study. Sprinting performance (10 m, 30 m, and 100 m from the block start), strength (back squat, back extension), and jumping ability (standing long jump, standing five-jumps, and standing ten-jumps) were tested. An independent t-test for establishing differences between two groups of athletes was used. The Spearman ranking correlation coefficient was computed to verify the association between variables. Additionally, the Ward method of hierarchical cluster analysis was applied. The recorded times of the 10 and 30 m indicated that the strongest correlations were found between a 1-repetition maximum back squat, a standing long jump, standing five jumps, standing ten jumps (r = 0.66, r = 0.72, r = 0.66, and r = 0.72), and speed in the 10 m sprint in competitive athletes. A strong correlation was also found between a 1-repetition maximum back squat and a standing long jump, standing five jumps, and standing ten jumps (r = 0.88, r = 0.87 and r = 0.85), but again only for sprinters. The most important factor for differences in maximum speed development during both the initial and secondary acceleration phase among the two sub-groups was the stride frequency (p<0.01).

  11. Selected Determinants of Acceleration in the 100m Sprint

    PubMed Central

    Maćkała, Krzysztof; Fostiak, Marek; Kowalski, Kacper

    2015-01-01

    The goal of this study was to examine the relationship between kinematics, motor abilities, anthropometric characteristics, and the initial (10 m) and secondary (30 m) acceleration phases of the 100 m sprint among athletes of different sprinting performances. Eleven competitive male sprinters (10.96 s ± 0.36 for 100 with 10.50 s fastest time) and 11 active students (12.20 s ± 0.39 for 100 m with 11.80 s fastest time) volunteered to participate in this study. Sprinting performance (10 m, 30 m, and 100 m from the block start), strength (back squat, back extension), and jumping ability (standing long jump, standing five-jumps, and standing ten-jumps) were tested. An independent t-test for establishing differences between two groups of athletes was used. The Spearman ranking correlation coefficient was computed to verify the association between variables. Additionally, the Ward method of hierarchical cluster analysis was applied. The recorded times of the 10 and 30 m indicated that the strongest correlations were found between a 1-repetition maximum back squat, a standing long jump, standing five jumps, standing ten jumps (r = 0.66, r = 0.72, r = 0.66, and r = 0.72), and speed in the 10 m sprint in competitive athletes. A strong correlation was also found between a 1-repetition maximum back squat and a standing long jump, standing five jumps, and standing ten jumps (r = 0.88, r = 0.87 and r = 0.85), but again only for sprinters. The most important factor for differences in maximum speed development during both the initial and secondary acceleration phase among the two sub-groups was the stride frequency (p<0.01). PMID:25964817

  12. Selected determinants of acceleration in the 100m sprint.

    PubMed

    Maćkała, Krzysztof; Fostiak, Marek; Kowalski, Kacper

    2015-03-29

    The goal of this study was to examine the relationship between kinematics, motor abilities, anthropometric characteristics, and the initial (10 m) and secondary (30 m) acceleration phases of the 100 m sprint among athletes of different sprinting performances. Eleven competitive male sprinters (10.96 s ± 0.36 for 100 with 10.50 s fastest time) and 11 active students (12.20 s ± 0.39 for 100 m with 11.80 s fastest time) volunteered to participate in this study. Sprinting performance (10 m, 30 m, and 100 m from the block start), strength (back squat, back extension), and jumping ability (standing long jump, standing five-jumps, and standing ten-jumps) were tested. An independent t-test for establishing differences between two groups of athletes was used. The Spearman ranking correlation coefficient was computed to verify the association between variables. Additionally, the Ward method of hierarchical cluster analysis was applied. The recorded times of the 10 and 30 m indicated that the strongest correlations were found between a 1-repetition maximum back squat, a standing long jump, standing five jumps, standing ten jumps (r = 0.66, r = 0.72, r = 0.66, and r = 0.72), and speed in the 10 m sprint in competitive athletes. A strong correlation was also found between a 1-repetition maximum back squat and a standing long jump, standing five jumps, and standing ten jumps (r = 0.88, r = 0.87 and r = 0.85), but again only for sprinters. The most important factor for differences in maximum speed development during both the initial and secondary acceleration phase among the two sub-groups was the stride frequency (p<0.01). PMID:25964817

  13. Athlete's Foot

    MedlinePlus

    ... Homework? Here's Help White House Lunch Recipes Athlete's Foot KidsHealth > For Kids > Athlete's Foot Print A A ... a public shower. Why Is It Called Athlete's Foot? Athlete's foot gets its name because athletes often ...

  14. Effects of beta-alanine supplementation on sprint endurance.

    PubMed

    Jagim, Andrew R; Wright, Glenn A; Brice, A Glenn; Doberstein, Scott T

    2013-02-01

    Recent research has shown that beta-alanine (BA) supplementation can increase intramuscular carnosine levels. Carnosine is an intramuscular buffer, and it has been linked to improvements in performance, specifically during bouts of high-intensity exercise that are likely limited by muscle acidosis. Therefore, the purpose of this study was to examine the effect of BA supplementation on sprint endurance at 2 different supramaximal intensities. Twenty-one anaerobically trained (rugby players [n = 4], wrestlers [n = 11], and recreationally strength trained athletes [n = 6]) college-aged men participated in a double-blind, placebo controlled study. The subjects performed an incremental VO2max test and 2 sprint to exhaustion tests set at 115 and 140% of their VO2max on a motorized treadmill before (PRE) and after (POST) a 5-week supplementation period. During this time, the subjects ingested either a BA supplement or placebo (PLA) with meals. The subjects ingested 4 g·d(-1) of BA or PLA during the first week and 6 g·d(-1) the following 4 weeks. Capillary blood samples were taken before and after each sprint to determine blood lactate response to the sprint exercise. No significant group (BA, PLA) × intensity (115%, 140%; p = 0.60), group by time (PRE, POST; p = 0.72), or group × intensity × time (p = 0.74) interactions were observed for time to exhaustion. In addition, similar nonsignificant observations were made for lactate response to the sprints (group × intensity, p = 0.43; group × time, p = 0.33, group × intensity × time, p = 0.56). From the results of this study, it was concluded that beta-alanine supplementation did not have a significant effect on sprint endurance at supramaximal intensities.

  15. Sprint Running Performance Monitoring: Methodological and Practical Considerations.

    PubMed

    Haugen, Thomas; Buchheit, Martin

    2016-05-01

    The aim of this review is to investigate methodological concerns associated with sprint performance monitoring, more specifically the influence and magnitude of varying external conditions, technology and monitoring methodologies not directly related to human physiology. The combination of different starting procedures and triggering devices can cause up to very large time differences, which may be many times greater than performance changes caused by years of conditioning. Wind, altitude, temperature, barometric pressure and humidity can all combine to yield moderate time differences over short sprints. Sprint performance can also be affected by the athlete's clothing, principally by its weight rather than its aerodynamic properties. On level surfaces, the track compliance must change dramatically before performance changes larger than typical variation can be detected. An optimal shoe bending stiffness can enhance performance by a small margin. Fully automatic timing systems, dual-beamed photocells, laser guns and high-speed video are the most accurate tools for sprint performance monitoring. Manual timing and single-beamed photocells should be avoided over short sprint distances (10-20 m) because of large absolute errors. The validity of today's global positioning systems (GPS) technology is satisfactory for long distances (>30 m) and maximal velocity in team sports, but multiple observations are still needed as reliability is questionable. Based on different approaches used to estimate the smallest worthwhile performance change and the typical error of sprint measures, we have provided an assessment of the usefulness of speed evaluation from 5 to 40 m. Finally, we provide statistical guidelines to accurately assess changes in individual performance; i.e. considering both the smallest worthwhile change in performance and the typical error of measurement, which can be reduced while repeating the number of trials.

  16. Sprint Running Performance Monitoring: Methodological and Practical Considerations.

    PubMed

    Haugen, Thomas; Buchheit, Martin

    2016-05-01

    The aim of this review is to investigate methodological concerns associated with sprint performance monitoring, more specifically the influence and magnitude of varying external conditions, technology and monitoring methodologies not directly related to human physiology. The combination of different starting procedures and triggering devices can cause up to very large time differences, which may be many times greater than performance changes caused by years of conditioning. Wind, altitude, temperature, barometric pressure and humidity can all combine to yield moderate time differences over short sprints. Sprint performance can also be affected by the athlete's clothing, principally by its weight rather than its aerodynamic properties. On level surfaces, the track compliance must change dramatically before performance changes larger than typical variation can be detected. An optimal shoe bending stiffness can enhance performance by a small margin. Fully automatic timing systems, dual-beamed photocells, laser guns and high-speed video are the most accurate tools for sprint performance monitoring. Manual timing and single-beamed photocells should be avoided over short sprint distances (10-20 m) because of large absolute errors. The validity of today's global positioning systems (GPS) technology is satisfactory for long distances (>30 m) and maximal velocity in team sports, but multiple observations are still needed as reliability is questionable. Based on different approaches used to estimate the smallest worthwhile performance change and the typical error of sprint measures, we have provided an assessment of the usefulness of speed evaluation from 5 to 40 m. Finally, we provide statistical guidelines to accurately assess changes in individual performance; i.e. considering both the smallest worthwhile change in performance and the typical error of measurement, which can be reduced while repeating the number of trials. PMID:26660758

  17. Ethnicity and spatiotemporal parameters of bilateral and unilateral transtibial amputees in a 100-m sprint.

    PubMed

    Hobara, Hiroaki; Hashizume, Satoru; Kobayashi, Yoshiyuki; Usami, Yuko; Mochimaru, Masaaki

    2016-01-01

    Similar to able-bodied sprinters, most of the medals for the 100-m sprint in past Paralympic Games and IPC Athletics World Championships were dominated by West African (WA) and Caucasian (CC) amputee sprinters, not Asian (AS) sprinters. Although these results indicate differences in sprint performance due to ethnicity, little is known about the ethnicity and spatiotemporal parameters of the 100-m sprint for amputee sprinters. The purpose of this study was to investigate the differences in the spatiotemporal parameters of WA, CC and AS sprinters with bilateral and unilateral transtibial amputations during a 100-m sprint. We analyzed 6 WA, 28 CC, and 10 AS amputee sprinters from publicly available Internet broadcasts. For each sprinter's run, the average speed, average step length, and step frequency were calculated by using the number of steps in conjunction with the official race time. No significant differences were found in the spatiotemporal parameters of the 100-m sprint for the WA and CC groups. On the other hand, the average speed of the AS group was significantly lower because of its shorter step length during the 100-m sprint. The results suggest that WA and CC sprinters would perform similarly during a 100-m sprint, but AS sprinters would not. PMID:27066362

  18. Assessment of sprint and change-of-direction performance in college football players.

    PubMed

    Condello, Giancarlo; Schultz, Kevin; Tessitore, Antonio

    2013-03-01

    The aim of the current study was to investigate the relationship between straight-sprint and change-of-direction performance. Total sprinting time and split time at 5 m were collected from 44 college football players during a 15-m straight sprint (SS15m) and a 15-m zigzag sprint with two 60° changes of direction (COD15m). Differences in sprinting time between COD15m and SS15m and between COD5m and SS5m were expressed as percentage of decrement at 5 m and 15 m (Δ%5m and Δ%15m). Significant and high correlations emerged between SS15m and COD15m (r = .86, P < .0001), SS5m and SS15m (r = .92, P < .0001), SS5m and COD5m (r = .92, P < .0001), and COD5m and COD15m (r = .71, P < .0001). Δ%5m and Δ%15m showed a range of 1.2-30.0% and 34.9-59.4%, respectively. These results suggested how straight-sprint and change-of-direction performance are similar abilities in college football players, in particular when a smaller angle of the change of direction is considered. Moreover, it seems necessary to have athletes undergo tests that mimic the demands of football game, which is characterized by sprint on short distances and with changes of direction.

  19. Relationships Between Vertical Jump Strength Metrics and 5 Meters Sprint Time

    PubMed Central

    Marques, Mário C.; Gil, Helena; Ramos, Rui J.; Costa, Aldo M.; Marinho, Daniel A.

    2011-01-01

    The aim of this study was to examine the relationship between short sprint time (5 m) and strength metrics of the countermovement jump (CMJ) using a linear transducer in a group of trained athletes. Twenty-five male, trained subjects volunteered to participate in the study. Each volunteer performed 3 maximal CMJ trials on a Smith machine. Peak instantaneous power was calculated by the product of velocity taken with the linear transducer. For sprint testing, each subject performed three maximum 5 m sprints. Only the best attempt was considered in both tests. Pearson product–moment correlation coefficients between 5 m sprint performance and strength metrics of the CMJ were generally positive and of clear moderate to strong magnitude (r = −0.664 to −0.801). More noticeable was the significant predictive value of bar displacement time (r= ∼0.70) to sprint performance. Nevertheless, a non-significant predictive value of peak bar velocity and rate of force development measurements was found. These results underline the important relationship between 5 m sprint and maximal lower body strength, as assessed by the force, power and bar velocity displacement. It is suggested that sprinting time performance would benefit from training regimens aimed to improve these performance qualities. PMID:23486705

  20. Ethnicity and spatiotemporal parameters of bilateral and unilateral transtibial amputees in a 100-m sprint.

    PubMed

    Hobara, Hiroaki; Hashizume, Satoru; Kobayashi, Yoshiyuki; Usami, Yuko; Mochimaru, Masaaki

    2016-01-01

    Similar to able-bodied sprinters, most of the medals for the 100-m sprint in past Paralympic Games and IPC Athletics World Championships were dominated by West African (WA) and Caucasian (CC) amputee sprinters, not Asian (AS) sprinters. Although these results indicate differences in sprint performance due to ethnicity, little is known about the ethnicity and spatiotemporal parameters of the 100-m sprint for amputee sprinters. The purpose of this study was to investigate the differences in the spatiotemporal parameters of WA, CC and AS sprinters with bilateral and unilateral transtibial amputations during a 100-m sprint. We analyzed 6 WA, 28 CC, and 10 AS amputee sprinters from publicly available Internet broadcasts. For each sprinter's run, the average speed, average step length, and step frequency were calculated by using the number of steps in conjunction with the official race time. No significant differences were found in the spatiotemporal parameters of the 100-m sprint for the WA and CC groups. On the other hand, the average speed of the AS group was significantly lower because of its shorter step length during the 100-m sprint. The results suggest that WA and CC sprinters would perform similarly during a 100-m sprint, but AS sprinters would not.

  1. Eight Weeks of Kettlebell Swing Training Does not Improve Sprint Performance in Recreationally Active Females

    PubMed Central

    HOLMSTRUP, MICHAEL E.; JENSEN, BROCK T.; EVANS, WILLIAM S.; MARSHALL, EMILY C.

    2016-01-01

    The kettlebell swing (KBS), emphasizing cyclical, explosive hip extension in the horizontal plane, aligns with movement- and velocity-specificity of sprinting. The present study examined the effect of an eight-week KBS intervention on sprinting in recreationally-active females, in comparison to an eight-week intervention using the stiff-legged deadlift (SDL). Following a pre-testing session measuring 30 meter sprint and countermovement vertical jump performance, participants were divided evenly by sprint time into KBS (n=8) and SDL (n=10) cohorts. Following familiarization with the exercises, KBS met twice weekly to perform swings using the Tabata interval (20s work, 10s rest, 8 rounds), stressing a rapid, explosive tempo. In contrast, the SDL group performed their Tabata stiff-legged deadlifts at a conventional resistance training tempo (2 seconds concentric, 2 seconds eccentric). Following eight weeks and greater than 95% training adherence, the SDL group only had a slightly greater average training volume (~3%) than KBS. No significant differences in pre-test values, or changes were noted in sprint performance from pre- to post-intervention in either group. An improvement in vertical jump performance was noted across groups. Potential explanations for the lack of sprint improvement compared to previous studies include differences between recreationally-active and athletic females, and low exercise volume (~46% of a comparable study with improvements in vertical jump). Future studies should seek to determine the appropriate volume and intensity for KBS components of sprint programming. PMID:27766131

  2. Sprint starts and the minimum auditory reaction time.

    PubMed

    Pain, Matthew T G; Hibbs, Angela

    2007-01-01

    The simple auditory reaction time is one of the fastest reaction times and is thought to be rarely less than 100 ms. The current false start criterion in a sprint used by the International Association of Athletics Federations is based on this assumed auditory reaction time of 100 ms. However, there is evidence, both anecdotal and from reflex research, that simple auditory reaction times of less than 100 ms can be achieved. Reaction time in nine athletes performing sprint starts in four conditions was measured using starting blocks instrumented with piezoelectric force transducers in each footplate that were synchronized with the starting signal. Only three conditions were used to calculate reaction times. The pre-motor and pseudo-motor time for two athletes were also measured across 13 muscles using surface electromyography (EMG) synchronized with the rest of the system. Five of the athletes had mean reaction times of less than 100 ms in at least one condition and 20% of all starts in the first two conditions had a reaction time of less than 100 ms. The results demonstrate that the neuromuscular-physiological component of simple auditory reaction times can be under 85 ms and that EMG latencies can be under 60 ms. PMID:17127583

  3. The impact of the achievement motive on athletic performance in adolescent football players.

    PubMed

    Zuber, Claudia; Conzelmann, Achim

    2014-01-01

    Researchers largely agree that there is a positive relationship between achievement motivation and athletic performance, which is why the achievement motive is viewed as a potential criterion for talent. However, the underlying mechanism behind this relationship remains unclear. In talent and performance models, main effect, mediator and moderator models have been suggested. A longitudinal study was carried out among 140 13-year-old football talents, using structural equation modelling to determine which model best explains how hope for success (HS) and fear of failure (FF), which are the aspects of the achievement motive, motor skills and abilities that affect performance. Over a period of half a year, HS can to some extent explain athletic performance, but this relationship is not mediated by the volume of training, sport-specific skills or abilities, nor is the achievement motive a moderating variable. Contrary to expectations, FF does not explain any part of performance. Aside from HS, however, motor abilities and in particular skills also predict a significant part of performance. The study confirms the widespread assumption that the development of athletic performance in football depends on multiple factors, and in particular that HS is worth watching in the medium term as a predictor of talent.

  4. The approach to elbow pain in the pediatric and adolescent throwing athlete.

    PubMed

    Hammoud, Sommer; Sgromolo, Nicole; Atanda, Alfred

    2014-02-01

    Elbow pain in pediatric throwing athletes can be very concerning and challenging to diagnose. Diagnosis involves determining whether the injury is chronic or acute in nature and the anatomical location of the pain. Physicians should be aware of the sport-specific forces that predispose athletes with immature skeletons to injury and should be familiar with the common presentations of these injuries. In order to narrow the diagnosis, physicians should gather a detailed history of how and when the pain occurred in addition to performing a thorough physical exam that includes tests, such as the modified milking maneuver and the moving valgus stress test. Appropriate imaging helps physicians to confirm the diagnosis and elucidates any associated pathology in patients. In most cases, the treatment given to patients is conservative and involves rest, ice, non-steroidal anti-inflammatory drugs for pain, and an appropriate physical therapy regimen with a progressive return to play when symptoms have resolved. When patients fail to respond to conservative treatment, surgical intervention may be needed. Knowing when to refer patients for orthopedic evaluation helps athletes return to play quickly and safely.

  5. The approach to elbow pain in the pediatric and adolescent throwing athlete.

    PubMed

    Hammoud, Sommer; Sgromolo, Nicole; Atanda, Alfred

    2014-02-01

    Elbow pain in pediatric throwing athletes can be very concerning and challenging to diagnose. Diagnosis involves determining whether the injury is chronic or acute in nature and the anatomical location of the pain. Physicians should be aware of the sport-specific forces that predispose athletes with immature skeletons to injury and should be familiar with the common presentations of these injuries. In order to narrow the diagnosis, physicians should gather a detailed history of how and when the pain occurred in addition to performing a thorough physical exam that includes tests, such as the modified milking maneuver and the moving valgus stress test. Appropriate imaging helps physicians to confirm the diagnosis and elucidates any associated pathology in patients. In most cases, the treatment given to patients is conservative and involves rest, ice, non-steroidal anti-inflammatory drugs for pain, and an appropriate physical therapy regimen with a progressive return to play when symptoms have resolved. When patients fail to respond to conservative treatment, surgical intervention may be needed. Knowing when to refer patients for orthopedic evaluation helps athletes return to play quickly and safely. PMID:24565822

  6. Assessment and treatment of knee pain in the child and adolescent athlete.

    PubMed

    Yen, Yi-Meng

    2014-12-01

    Knee pain in children and adolescents is one of the most prevalent complaints in a pediatric practice, accounting for at least a third of musculoskeletal complaints. Accurate diagnosis requires an understanding of knee anatomy and patterns of knee injuries and skill in physical examination. This review covers the most common causes of knee pain in children and adolescents, including overuse issues, such as Osgood-Schlatter and osteochondritis dissecans, as well as traumatic injuries, including tibial spine fractures and anterior cruciate ligament injuries.

  7. Body weight changes in child and adolescent athletes during a triathlon competition.

    PubMed

    Aragón-Vargas, Luis Fernando; Wilk, Boguslaw; Timmons, Brian W; Bar-Or, Oded

    2013-01-01

    We examined young athletes during a triathlon performed in a hot climate. Complete or partial data were available for 95 athletes competing in the National Triathlon Championship in Costa Rica. Mean ± SD for age and body weight (BW) were 13.1 ± 2.5 years and 46.3 ± 11.5 kg, respectively. Race requirements included: 500 m swimming, 15 km cycling, 3.5 km running for juniors (9-13 years); 800 m swimming, 30 km cycling, 8 km running for seniors (14-17 years). WBGT on race day was >31 °C. BW recorded pre- and post-race was available for 92 athletes and performance data were available for 83 of these. Information regarding symptoms experienced during the race was available for 95 athletes. Change in BW (%ΔBW) was calculated and ranged from +0.6 to -2.4 % for junior boys (-1.2 ± 0.9 %), +0.7 to -2.5 % for junior girls (-1.3 ± 0.9 %), 0 to -2.8 % for senior girls (-1.3 ± 0.9 %), and +0.6 to -4.5 % for senior boys (-1.7 ± 1.1 %). Eighteen participants reported no medical symptoms. Of 77 participants who reported symptoms, 42.9 % reported exhaustion/fatigue, 36.4 % reported side stitch/cramp, and 23.4 % reported dizziness. Participants reporting no medical symptoms achieved almost identical (P = 0.99) %ΔBW as those reporting at least one symptom. %ΔBW was more negative (P = 0.005) in participants who reported dizziness (-1.9 %ΔBW) compared with those who did not (-1.4 %ΔBW). %ΔBW was associated with performance in junior girls (r = 0.47, P = 0.02) and senior boys (r = 0.51, P = 0.01), with a trend in junior boys (r = 0.41, P = 0.053) but not in senior girls (r = 0.004, P = 0.99). Young athletes participating in a triathlon in a hot climate can tolerate mild to moderate levels of dehydration, without detrimental effects to self-assessed health.

  8. Baseline strength can influence the ability of salivary free testosterone to predict squat and sprinting performance.

    PubMed

    Crewther, Blair T; Cook, Christian J; Gaviglio, Chris M; Kilduff, Liam P; Drawer, Scott

    2012-01-01

    The objective of this study was to determine if salivary free testosterone can predict an athlete's performance during back squats and sprints over time and the influence baseline strength on this relationship. Ten weight-trained male athletes were divided into 2 groups based on their 1 repetition maximum (1RM) squats, good squatters (1RM > 2.0 × body weight, n = 5) and average squatters (1RM < 1.9 × body weight, n = 5). The good squatters were stronger than the average squatters (p < 0.05). Each subject was assessed for squat 1RM and 10-m sprint times on 10 separate occasions over a 40-day period. A saliva sample was collected before testing and assayed for free testosterone and cortisol. The pooled testosterone correlations were strong and significant in the good squatters (r = 0.92 for squats, r = -0.87 for sprints, p < 0.01), but not significant for the average squatters (r = 0.35 for squats, r = -0.18 for sprints). Cortisol showed no significant correlations with 1RM squat and 10-m sprint performance, and no differences were identified between the 2 squatting groups. In summary, these results suggest that free testosterone is a strong individual predictor of squat and sprinting performance in individuals with relatively high strength levels but a poor predictor in less strong individuals. This information can assist coaches, trainers, and performance scientists working with stronger weight-trained athletes, for example, the preworkout measurement of free testosterone could indicate likely training outcomes or a readiness to train at a certain intensity level, especially if real-time measurements are made. Our results also highlight the need to separate group and individual hormonal data during the repeated testing of athletes with variable strength levels.

  9. Asymmetry in Determinants of Running Speed During Curved Sprinting.

    PubMed

    Ishimura, Kazuhiro; Sakurai, Shinji

    2016-08-01

    This study investigates the potential asymmetries between inside and outside legs in determinants of curved running speed. To test these asymmetries, a deterministic model of curved running speed was constructed based on components of step length and frequency, including the distances and times of different step phases, takeoff speed and angle, velocities in different directions, and relative height of the runner's center of gravity. Eighteen athletes sprinted 60 m on the curved path of a 400-m track; trials were recorded using a motion-capture system. The variables were calculated following the deterministic model. The average speeds were identical between the 2 sides; however, the step length and frequency were asymmetric. In straight sprinting, there is a trade-off relationship between the step length and frequency; however, such a trade-off relationship was not observed in each step of curved sprinting in this study. Asymmetric vertical velocity at takeoff resulted in an asymmetric flight distance and time. The runners changed the running direction significantly during the outside foot stance because of the asymmetric centripetal force. Moreover, the outside leg had a larger tangential force and shorter stance time. These asymmetries between legs indicated the outside leg plays an important role in curved sprinting. PMID:27046932

  10. Anaerobic work capacity in elite wheelchair athletes.

    PubMed

    van der Woude, L H; Bakker, W H; Elkhuizen, J W; Veeger, H E; Gwinn, T

    1997-01-01

    To study the anaerobic work capacity in wheelchair athletes, 67 elite wheelchair athletes (50 male) were studied in a 30-second sprint test on a computer-controlled wheelchair ergometer during the World Championships and Games for the Disabled in Assen (1990). The experimental set-up (ergometer, protocol) proved to be adequate in terms of power output (P30, P5) velocity and heart rate. Male and female athletes were comparable with respect to personal characteristics (age, body weight, training hours). Track athletes (classified in 4 different functional classes) showed a class-related mean power output (P30: mean power produced during the 30-second sprint period) of 23, 68, 100, and 138 W for the male athletes (n = 38) and 38, 77, and 76 W for females in the upper three classes (n = 10). Sprint power was low for the group of subjects with cerebral palsy (35 W; mixed, n = 6) and relatively high for the amputee group (121 W; mixed, n = 6), female basketball players (81 W; n = 5), and two male field athletes (110 W). Significant differences between male and female athletes were found for P30 and P5 (highest mean power output over any of the six 5-second periods). As was to be expected, mean maximum heart rate in the sprint test varied significantly between the track groups from 112 (high lesion group) to 171 beats/minute(-1) (low lesion group) but not for both genders. The lower P30 in the T1 and T2 groups must be explained not only by the reduced functional muscle mass and impaired coordination but also by phenomena of cardiovascular dysfunction. Based on the performance parameters, the functional classification of the track athletes into four groups seems adequate. P30 was significantly associated with the personal characteristics of gender and hours of training. A significant correlation was found between P30 and sprint performance times for 200 meters (r = -0.79). No correlation was found between either of the forms of power output and the marathon times

  11. Squat jump training at maximal power loads vs. heavy loads: effect on sprint ability.

    PubMed

    Harris, Nigel K; Cronin, John B; Hopkins, Will G; Hansen, Keir T

    2008-11-01

    Training at a load maximizing power output (Pmax) is an intuitively appealing strategy for enhancement of performance that has received little research attention. In this study we identified each subject's Pmax for an isoinertial resistance training exercise used for testing and training, and then we related the changes in strength to changes in sprint performance. The subjects were 18 well-trained rugby league players randomized to two equal-volume training groups for a 7-week period of squat jump training with heavy loads (80% 1RM) or with individually determined Pmax loads (20.0-43.5% 1RM). Performance measures were 1RM strength, maximal power at 55% of pretraining 1RM, and sprint times for 10 and 30 m. Percent changes were standardized to make magnitude-based inferences. Relationships between changes in these variables were expressed as correlations. Sprint times for 10 m showed improvements in the 80% 1RM group (-2.9 +/- 3.2%) and Pmax group (-1.3 +/- 2.2%), and there were similar improvements in 30-m sprint time (-1.9 +/- 2.8 and -1.2 +/- 2.0%, respectively). Differences in the improvements in sprint time between groups were unclear, but improvement in 1RM strength in the 80% 1RM group (15 +/- 9%) was possibly substantially greater than in the Pmax group (11 +/- 8%). Small-moderate negative correlations between change in 1RM and change in sprint time (r approximately -0.30) in the combined groups provided the only evidence of adaptive associations between strength and power outputs, and sprint performance. In conclusion, it seems that training at the load that maximizes individual peak power output for this exercise with a sample of professional team sport athletes was no more effective for improving sprint ability than training at heavy loads, and the changes in power output were not usefully related to changes in sprint ability.

  12. On the relationship between upper-body strength, power, and sprint performance in ice sledge hockey.

    PubMed

    Skovereng, Knut; Ettema, Gertjan; Welde, Boye; Sandbakk, Øyvind

    2013-12-01

    Ice sledge hockey is a popular paralympic team sport where players rely entirely on their upper body to propel themselves rapidly across the ice surface. The isolated and repetitive poling movements provide a good model for examining upper-body sprint ability and the related movement and strength characteristics. Therefore, the purpose of the present study was to investigate the relationship between upper-body maximal strength, power, and sprint performance in ice sledge hockey. Thirteen male ice sledge hockey players from the Norwegian national team performed three 30-m maximal sprint tests recorded by fixed light sensors. The best 30-m time for each subject was used for further analyses, and the sprint was analyzed more in detail for the first and last 10-m split times and kinematics (cycle length and rate) using photocells and 2-dimensional video analysis. One repetition maximum (1RM) strength and peak power were assessed in the bench press, bench pull, and pull-down exercises using a barbell and a linear encoder. Both 1RM strength and peak power for all the 3 strength exercises correlated significantly with the total sprint time (-0.75 < r < - 0.86, all p < 0.005), the first (0.60 < r < 0.72, all p < 0.05), and the last (0.74 < r < 0.83, all p < 0.05) 10-m split times in the 30-m sprint test. There were no significant relationships between sprint kinematics and 1RM strength and peak power. Overall, these results demonstrate that there are close relationships between upper-body strength, power, and sprint performance in highly trained athletes and that the ability to produce propulsion and high frequency in combination is important for the sprint abilities in ice sledge hockey.

  13. Effects of combined creatine and sodium bicarbonate supplementation on repeated sprint performance in trained men.

    PubMed

    Barber, James J; McDermott, Ann Y; McGaughey, Karen J; Olmstead, Jennifer D; Hagobian, Todd A

    2013-01-01

    Creatine and sodium bicarbonate supplementation independently increase exercise performance, but it remains unclear whether combining these 2 supplements is more beneficial on exercise performance. The purpose of this study was to evaluate the impact of combining creatine monohydrate and sodium bicarbonate supplementation on exercise performance. Thirteen healthy, trained men (21.1 ± 0.6 years, 23.5 ± 0.5 kg·m(-2), 66.7 ± 5.7 ml·(kg·m)(-1) completed 3 conditions in a double-blinded, crossover fashion: (a) Placebo (Pl; 20 g maltodextrin + 0.5 g·kg(-1) maltodextrin), (b) Creatine (Cr; 20 g + 0.5 g·kg(-1) maltodextrin), and (c) Creatine plus sodium bicarbonate (Cr + Sb; 20 g + 0.5 g·kg(-1) sodium bicarbonate). Each condition consisted of supplementation for 2 days followed by a 3-week washout. Peak power, mean power, relative peak power, and bicarbonate concentrations were assessed during six 10-second repeated Wingate sprint tests on a cycle ergometer with a 60-second rest period between each sprint. Compared with Pl, relative peak power was significantly higher in Cr (4%) and Cr + Sb (7%). Relative peak power was significantly lower in sprints 4-6, compared with that in sprint 1, in both Pl and Cr. However, in Cr + Sb, sprint 6 was the only sprint significantly lower compared with sprint 1. Pre-Wingate bicarbonate concentrations were significantly higher in Cr + Sb (10%), compared with in Pl and Cr, and mean concentrations remained higher after sprint 6, although not significantly. Combining creatine and sodium bicarbonate supplementation increased peak and mean power and had the greatest attenuation of decline in relative peak power over the 6 repeated sprints. These data suggest that combining these 2 supplements may be advantageous for athletes participating in high-intensity, intermittent exercise.

  14. Basal Metabolic Rate of Adolescent Modern Pentathlon Athletes: Agreement between Indirect Calorimetry and Predictive Equations and the Correlation with Body Parameters

    PubMed Central

    Loureiro, Luiz Lannes; Fonseca, Sidnei; Castro, Natalia Gomes Casanova de Oliveira e; dos Passos, Renata Baratta; Porto, Cristiana Pedrosa Melo; Pierucci, Anna Paola Trindade Rocha

    2015-01-01

    Purpose The accurate estimative of energy needs is crucial for an optimal physical performance among athletes and the basal metabolic rate (BMR) equations often are not well adjusted for adolescent athletes requiring the use of specific methods, such as the golden standard indirect calorimetry (IC). Therefore, we had the aim to analyse the agreement between the BMR of adolescents pentathletes measured by IC and estimated by commonly used predictive equations. Methods Twenty-eight athletes (17 males and 11 females) were evaluated for BMR, using IC and the predictive equations Harris and Benedict (HB), Cunningham (CUN), Henry and Rees (HR) and FAO/WHO/UNU (FAO). Body composition was obtained using DXA and sexual maturity data were retrieved through validated questionnaires. The correlations among anthropometric variables an IC were analysed by T-student test and ICC, while the agreement between IC and the predictive equations was analysed according to Bland and Altman and by survival-agreement plotting. Results The whole sample average BMR measured by IC was significantly different from the estimated by FAO (p<0.05). Adjusting data by gender FAO and HR equations were statistically different from IC (p <0.05) among males, while female differed only for the HR equation (p <0.05). Conclusion The FAO equation underestimated athletes’ BMR when compared with IC (T Test). When compared to the golden standard IC, using Bland and Altman, ICC and Survival-Agreement, the equations underestimated the energy needs of adolescent pentathlon athletes up to 300kcal/day. Therefore, they should be used with caution when estimating individual energy requirements in such populations. PMID:26569101

  15. Supplement use by Young Athletes

    PubMed Central

    McDowall, Jill Anne

    2007-01-01

    This paper reviews studies of supplement use among child and adolescent athletes, focusing on prevalence and type of supplement use, as well as gender comparisons. Supplement use among adult athletes has been well documented however there are a limited number of studies investigating supplement use by child and adolescent athletes. A trend in the current literature revealed that the most frequently used supplements are in the form of vitamin and minerals. While health and illness prevention are the main reasons for taking supplements, enhanced athletic performance was also reported as a strong motivating factor. Generally, females are found to use supplements more frequently and are associated with reasons of health, recovery, and replacing an inadequate diet. Males are more likely to report taking supplements for enhanced performance. Both genders equally rated increased energy as another reason for engaging in supplement use. Many dietary supplements are highly accessible to young athletes and they are particularly vulnerable to pressures from the media and the prospect of playing sport at increasingly elite levels. Future research should provide more direct evidence regarding any physiological side effects of taking supplements, as well as the exact vitamin and mineral requirements for child and adolescent athletes. Increased education for young athletes regarding supplement use, parents and coaches should to be targeted to help the athletes make the appropriate choices. Key pointsSupplement use among the child and adolescent athlete population is widespread with the most frequently used supplement being a form of vitamin/mineral supplement.The effects of supplement use on the growth and development of children and adolescents remain unclear and thus use of supplements by this population should be discouraged.It is likely that there is a misunderstanding as to the role of vitamins and minerals in the diet, their function in maintaining overall health, their role

  16. Accounting for elite indoor 200 m sprint results.

    PubMed

    Usherwood, James R; Wilson, Alan M

    2006-03-22

    Times for indoor 200 m sprint races are notably worse than those for outdoor races. In addition, there is a considerable bias against competitors drawn in inside lanes (with smaller bend radii). Centripetal acceleration requirements increase average forces during sprinting around bends. These increased forces can be modulated by changes in duty factor (the proportion of stride the limb is in contact with the ground). If duty factor is increased to keep limb forces constant, and protraction time and distance travelled during stance are unchanging, bend-running speeds are reduced. Here, we use results from the 2004 Olympics and World Indoor Championships to show quantitatively that the decreased performances in indoor competition, and the bias by lane number, are consistent with this 'constant limb force' hypothesis. Even elite athletes appear constrained by limb forces. PMID:17148323

  17. Extracurricular Activities, Athletic Participation, and Adolescent Alcohol Use: Gender-Differentiated and School-Contextual Effects

    ERIC Educational Resources Information Center

    Hoffmann, John P.

    2006-01-01

    This research investigates the effects of extracurricular activities on alcohol use among male (n = 4,495) and female (n = 5,398) adolescents who participated in the 1990-92 National Education Longitudinal Study. Previous studies have assessed the association between extracurricular activities and alcohol use, but none have explored whether the…

  18. Adolescent Athletic Participation and Nonmedical Adderall Use: An Exploratory Analysis of a Performance-Enhancing Drug

    PubMed Central

    Veliz, Philip; Boyd, Carol; McCabe, Sean Esteban

    2013-01-01

    Objective: A primary motive for adolescents and young adults to nonmedically use prescription stimulants is to help them study. Adolescents and young adults are using prescription stimulants, such as Adderall (amphetamine aspartate, amphetamine sulfate, dextroamphetamine saccharate, dextroamphetamine sulfate), as performance enhancers in certain social domains, including academics and sports. The purpose of this exploratory study was to examine the nonmedical use of Adderall (a commonly prescribed stimulant used nonmedically) among adolescents who participate in competitive sports. Method: The Monitoring the Future survey for 2010 and 2011, a representative sample of 8th- and 10th-grade students, surveyed involvement in competitive sports and nonmedical Adderall use among 21,137 adolescents. Pastyear nonmedical use of Adderall served as the main outcome measure. Logistic regression analyses were run to examine whether sports participation in general and involvement in different types of competitive sports participation were associated with past-year nonmedical use of Adderall among males and females. Results: The odds of past-year nonmedical use of Adderall among males were higher for male respondents who participated in lacrosse (adjusted odds ratio [AOR] = 2.52, 95% CI [1.20, 5.29]) and wrestling (AOR = 1.74, 95% CI [1.01, 2.98]). However, no particular sport among females was found to be associated with pastyear nonmedical use of Adderall. Conclusions: Certain extracurricular activities, such as high-contact sports, may influence male participants to misuse prescription stimulants as performance enhancers either on or off the playing field. PMID:23948530

  19. Evaluation and Management of Patellar Instability in Pediatric and Adolescent Athletes

    PubMed Central

    Khormaee, Sariah; Kramer, Dennis E.; Yen, Yi-Meng; Heyworth, Benton E.

    2015-01-01

    Context: The rising popularity and intensity of youth sports has increased the incidence of patellar dislocation. These sports-related injuries may be associated with significant morbidity in the pediatric population. Treatment requires understanding and attention to the unique challenges in the skeletally immature patient. Evidence Acquisition: PubMed searches spanning 1970-2013. Study Design: Clinical review. Level of Evidence: Level 5. Results: Although nonoperative approaches are most often suitable for first-time patellar dislocations, surgical treatment is recommended for acute fixation of displaced osteochondral fractures sustained during primary instability and for patellar realignment in the setting of recurrent instability. While a variety of procedures can prevent recurrence, the risk of complications is not minimal. Conclusion: Patellar stabilization and realignment procedures in skeletally immature patients with recurrent patellar dislocation can effectively treat patellar instability without untoward effects on growth if careful surgical planning incorporates protection of growth parameters in the skeletally immature athlete. PMID:25984256

  20. Acute effects of a caffeine-taurine energy drink on repeated sprint performance of American college football players.

    PubMed

    Gwacham, Nnamdi; Wagner, Dale R

    2012-04-01

    Consumption of energy drinks is common among athletes; however, there is a lack of research on the efficacy of these beverages for short-duration, intense exercise. The purpose of this research was to investigate the acute effects of a low-calorie caffeine-taurine energy drink (AdvoCare Spark) on repeated sprint performance and anaerobic power in National Collegiate Athletic Association Division I football players. Twenty football players (age 19.7 ± 1.8 yr, height 184.9 ± 5.3 cm, weight 100.3 ± 21.7 kg) participated in a double-blind, randomized crossover study in which they received the energy drink or an isoenergetic, isovolumetric, non-caffeinated placebo in 2 trials separated by 7 days. The Running Based Anaerobic Sprint Test, consisting of six 35-m sprints with 10 s of rest between sprints, was used to assess anaerobic power. Sprint times were recorded with an automatic electronic timer. The beverage treatment did not significantly affect power (F = 3.84, p = .066) or sprint time (F = 3.06, p = .097). However, there was a significant interaction effect between caffeine use and the beverage for sprint times (F = 4.62, p = .045), as well as for anaerobic power (F = 5.40, p = .032), indicating a confounding effect. In conclusion, a caffeine-taurine energy drink did not improve the sprint performance or anaerobic power of college football players, but the level of caffeine use by the athletes likely influenced the effect of the drink.

  1. Acute effects of a caffeine-taurine energy drink on repeated sprint performance of American college football players.

    PubMed

    Gwacham, Nnamdi; Wagner, Dale R

    2012-04-01

    Consumption of energy drinks is common among athletes; however, there is a lack of research on the efficacy of these beverages for short-duration, intense exercise. The purpose of this research was to investigate the acute effects of a low-calorie caffeine-taurine energy drink (AdvoCare Spark) on repeated sprint performance and anaerobic power in National Collegiate Athletic Association Division I football players. Twenty football players (age 19.7 ± 1.8 yr, height 184.9 ± 5.3 cm, weight 100.3 ± 21.7 kg) participated in a double-blind, randomized crossover study in which they received the energy drink or an isoenergetic, isovolumetric, non-caffeinated placebo in 2 trials separated by 7 days. The Running Based Anaerobic Sprint Test, consisting of six 35-m sprints with 10 s of rest between sprints, was used to assess anaerobic power. Sprint times were recorded with an automatic electronic timer. The beverage treatment did not significantly affect power (F = 3.84, p = .066) or sprint time (F = 3.06, p = .097). However, there was a significant interaction effect between caffeine use and the beverage for sprint times (F = 4.62, p = .045), as well as for anaerobic power (F = 5.40, p = .032), indicating a confounding effect. In conclusion, a caffeine-taurine energy drink did not improve the sprint performance or anaerobic power of college football players, but the level of caffeine use by the athletes likely influenced the effect of the drink. PMID:22349209

  2. Hyperventilation as a strategy for improved repeated sprint performance.

    PubMed

    Sakamoto, Akihiro; Naito, Hisashi; Chow, Chin-Moi

    2014-04-01

    Repeated high-intensity sprints incur substantial anaerobic metabolic challenges and create an acidic muscle milieu that is unfavorable for subsequent performance. Hyperventilation, resulting in respiratory alkalosis, acts as a compensatory mechanism for metabolic acidosis. This study tested the hypothesis that hyperventilation performed during recovery intervals would attenuate performance decrement in repeated sprint pedaling. Thirteen male university athletes performed 10 sets of 10-second maximal pedaling on a cycle ergometer with a 60-second recovery between sets under control (spontaneous breathing) and hyperventilation conditions in a crossover counter-balanced manner. Pedaling load was set at 0.075 × body mass. Peak and mean power outputs were documented for each set to compare performance decrements for 10 sets between conditions. Hyperventilation (60 breaths per minute and end-tidal partial pressure of CO2 maintained at 20-25 mm Hg) was performed 30 seconds before each sprint set. This intervention successfully increased blood pH by 0.03-0.07 but lowered P(CO2) by 1.2-8.4 mm Hg throughout exercise (p < 0.001). The peak and mean power outputs, and blood [La] accumulation were not significantly different between the conditions. However, a significant condition × time interaction existed for peak power (p = 0.035) and mean power (p = 0.023), demonstrating an attenuation in power decrement in later sprint sets with hyperventilation. In conclusion, hyperventilation implemented during recovery intervals of repeated sprint pedaling attenuated performance decrements in later exercise bouts that was associated with substantial metabolic acidosis. The practical implication is that hyperventilation may have a strategic role for enhancing training effectiveness and may give an edge in performance outcomes.

  3. Sprint running performance: comparison between treadmill and field conditions.

    PubMed

    Morin, Jean-Benoît; Sève, Pierrick

    2011-08-01

    We investigated the differences in performance between 100-m sprints performed on a sprint treadmill recently validated versus on a standard track. To date, studies comparing overground and treadmill running have mainly focused on constant and not maximal "free" running speed, and compared running kinetics and kinematics over a limited number of steps, but not overall sprint performance. Eleven male physical education students including two sprinters performed one 100-m on the treadmill and one on a standard athletics track in a randomized order, separated by 30 min. Performance data were derived in both cases from speed-time relationships measured with a radar and with the instrumented sprint treadmill, which allowed subjects to run and produce speed "freely", i.e. with no predetermined belt speed imposed. Field and treadmill typical speed-distance curves and data of maximal and mean speed, 100-m time and acceleration/deceleration time constants were compared using t tests and field-treadmill correlations were tested. All the performance parameters but time to reach top speed and deceleration time constant differed significantly, by about 20% on average, between field and treadmill (e.g. top speed of 8.84 ± 0.51 vs. 6.90 ± 0.39 m s(-1)). However, significant correlations were found (r > 0.63; P < 0.05) for all the performance parameters except time to reach top speed. Treadmill and field 100-m sprint performances are different, despite the fact that subjects could freely accelerate the belt. However, the significant correlations found make it possible to investigate and interpret inter-individual differences in field performance from treadmill measurements.

  4. Sprint running performance: comparison between treadmill and field conditions.

    PubMed

    Morin, Jean-Benoît; Sève, Pierrick

    2011-08-01

    We investigated the differences in performance between 100-m sprints performed on a sprint treadmill recently validated versus on a standard track. To date, studies comparing overground and treadmill running have mainly focused on constant and not maximal "free" running speed, and compared running kinetics and kinematics over a limited number of steps, but not overall sprint performance. Eleven male physical education students including two sprinters performed one 100-m on the treadmill and one on a standard athletics track in a randomized order, separated by 30 min. Performance data were derived in both cases from speed-time relationships measured with a radar and with the instrumented sprint treadmill, which allowed subjects to run and produce speed "freely", i.e. with no predetermined belt speed imposed. Field and treadmill typical speed-distance curves and data of maximal and mean speed, 100-m time and acceleration/deceleration time constants were compared using t tests and field-treadmill correlations were tested. All the performance parameters but time to reach top speed and deceleration time constant differed significantly, by about 20% on average, between field and treadmill (e.g. top speed of 8.84 ± 0.51 vs. 6.90 ± 0.39 m s(-1)). However, significant correlations were found (r > 0.63; P < 0.05) for all the performance parameters except time to reach top speed. Treadmill and field 100-m sprint performances are different, despite the fact that subjects could freely accelerate the belt. However, the significant correlations found make it possible to investigate and interpret inter-individual differences in field performance from treadmill measurements. PMID:21210279

  5. Time of Day – Effects on Motor Coordination and Reactive Strength in Elite Athletes and Untrained Adolescents

    PubMed Central

    di Cagno, Alessandra; Battaglia, Claudia; Giombini, Arrigo; Piazza, Marina; Fiorilli, Giovanni; Calcagno, Giuseppe; Pigozzi, Fabio; Borrione, Paolo

    2013-01-01

    Objectives: the issue of time-of-day effects on performance is crucial when considering the goal of reaching peak results in sport disciplines. The present study was designed to examine time-of-day effects in adolescents on motor coordination, assessed with Hirtz’s battery and neuromuscular components of strength, evaluated with reactive strength tests. Methods: forty-two elite female gymnasts, aged 13.3 ± 0.5 years (Mean ± SD), were recruited for the study. Fifty healthy female students (aged 12.8 ± 1.7 years) served as the control group. All participants underwent the testing sessions over two days at two different times of day in a randomized order. Results: Oral temperature was measured at the two times of the day and a significant diurnal variation (p < 0.01) in both groups was found. MANOVA revealed significant group differences in the overall tests (p < 0.01). The gymnast group showed no significant differences in the coordination tests with respect to the time of day, but significant differences were observed for reactive strength as assessed with the vertical jump tests (p < 0.01). Gyamnasts attained better results in the evening in the reactive strength tests [flight time (F1.90 = 17.322 p < 0.01) and ground contact time (F1.90 = 8.372; p < 0.01) of the hopping test]. Conclusion: the temperature effect was more evident in the reactive strength tests and orientation test, especially in the gymnast group in which this effect added to their usual training time effect. The time-since-awakening influenced coordination performances in complex tasks more than reaction strength tests in simple tasks. The main outcome of the study was that we did not observe time-of-day effects on coordination skills in elite gymnasts and in untrained adolescents. The time of day in which athletes usually trained these skills could influence these results. Key points The results obtained in this study suggested that the best time to perform a particular task depends

  6. Effects of sprint and plyometrics training on field sport acceleration technique.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Callaghan, Samuel J; Jeffriess, Matthew D

    2014-07-01

    The mechanisms for speed performance improvement from sprint training and plyometrics training, especially relating to stance kinetics, require investigation in field sport athletes. This study determined the effects of sprint training and plyometrics training on 10-m sprint time (0-5, 5-10, and 0-10 m intervals), step kinematics (step length and frequency, contact and flight time), and stance kinetics (first, second, and last contact relative vertical [VF, VI], horizontal [HF, HI], and resultant [RF, RI] force and impulse; resultant ground reaction force angle [RFθ]; ratio of horizontal to resultant force [RatF]) during a 10-m sprint. Sixteen male field sport athletes were allocated into sprint training (ST) and plyometrics training (PT) groups according to 10-m sprint time; independent samples t-tests (p ≤ 0.05) indicated no between-group differences. Training involved 2 sessions per week for 6 weeks. A repeated measures analysis of variance (p ≤ 0.05) determined within- and between-subject differences. Both groups decreased 0-5 and 0-10 m time. The ST group increased step length by ∼15%, which tended to be greater than step length gains for the PT group (∼7%). The ST group reduced first and second contact RFθ and RatF, and second contact HF. Second contact HI decreased for both groups. Results indicated a higher post-training emphasis on VF production. Vertical force changes were more pronounced for the PT group for the last contact, who increased or maintained last contact VI, RF, and RI to a greater extent than the ST group. Sprint and plyometrics training can improve acceleration, primarily through increased step length and a greater emphasis on VF.

  7. Computational Models Predict Larger Muscle Tissue Strains at Faster Sprinting Speeds

    PubMed Central

    Fiorentino, Niccolo M; Rehorn, Michael R; Chumanov, Elizabeth S; Thelen, Darryl G; Blemker, Silvia S

    2014-01-01

    Introduction: Proximal biceps femoris musculotendon strain injury has been well established as a common injury among athletes participating in sports that require sprinting near or at maximum speed; however, little is known about the mechanisms that make this muscle tissue more susceptible to injury at faster speeds. Purpose: Quantify localized tissue strain during sprinting at a range of speeds. Methods: Biceps femoris long head (BFlh) musculotendon dimensions of 14 athletes were measured on magnetic resonance (MR) images and used to generate a finite element computational model. The model was first validated through comparison with previous dynamic MR experiments. After validation, muscle activation and muscle-tendon unit length change were derived from forward dynamic simulations of sprinting at 70%, 85% and 100% maximum speed and used as input to the computational model simulations. Simulations ran from mid-swing to foot contact. Results: The model predictions of local muscle tissue strain magnitude compared favorably with in vivo tissue strain measurements determined from dynamic MR experiments of the BFlh. For simulations of sprinting, local fiber strain was non-uniform at all speeds, with the highest muscle tissue strain where injury is often observed (proximal myotendinous junction). At faster sprinting speeds, increases were observed in fiber strain non-uniformity and peak local fiber strain (0.56, 0.67 and 0.72, for sprinting at 70%, 85% and 100% maximum speed). A histogram of local fiber strains showed that more of the BFlh reached larger local fiber strains at faster speeds. Conclusions: At faster sprinting speeds, peak local fiber strain, fiber strain non-uniformity and the amount of muscle undergoing larger strains are predicted to increase, likely contributing to the BFlh muscle’s higher injury susceptibility at faster speeds. PMID:24145724

  8. ISS Update: SPRINT Exercise Program

    NASA Video Gallery

    NASA Public Affairs Officer Amiko Kauderer interviews Lori Ploutz-Snyder, Ph.D., NASA Lead Exercise Physiology Scientist, about the SPRINT exercise program used by the crew members aboard the Inter...

  9. Comparison of the Capacity of Different Jump and Sprint Field Tests to Detect Neuromuscular Fatigue.

    PubMed

    Gathercole, Rob J; Sporer, Ben C; Stellingwerff, Trent; Sleivert, Gord G

    2015-09-01

    Different jump and sprint tests have been used to assess neuromuscular fatigue, but the test with optimal validity remains to be established. The current investigation examined the suitability of vertical jump (countermovement jump [CMJ], squat jump [SJ], drop jump [DJ]) and 20-m sprint (SPRINT) testing for neuromuscular fatigue detection. On 6 separate occasions, 11 male team-sport athletes performed 6 CMJ, SJ, DJ, and 3 SPRINT trials. Repeatability was determined on the first 3 visits, with subsequent 3 visits (0-, 24-, and 72-hour postexercise) following a fatiguing Yo-Yo running protocol. SPRINT performance was most repeatable (mean coefficient of variation ≤2%), whereas DJ testing (4.8%) was significantly less repeatable than CMJ (3.0%) and SJ (3.5%). Each test displayed large decreases at 0-hour (33 of 49 total variables; mean effect size = 1.82), with fewer and smaller decreases at 24-hour postexercise (13 variables; 0.75), and 72-hour postexercise (19 variables; 0.78). SPRINT displayed the largest decreases at 0-hour (3.65) but was subsequently unchanged, whereas SJ performance recovered by 72-hour postexercise. In contrast, CMJ and DJ performance displayed moderate (12 variables; 1.18) and small (6 variables; 0.53) reductions at 72-hour postexercise, respectively. Consequently, the high repeatability and immediate and prolonged fatigue-induced changes indicated CMJ testing as most suitable for neuromuscular fatigue monitoring. PMID:26308829

  10. Comparison of the Capacity of Different Jump and Sprint Field Tests to Detect Neuromuscular Fatigue.

    PubMed

    Gathercole, Rob J; Sporer, Ben C; Stellingwerff, Trent; Sleivert, Gord G

    2015-09-01

    Different jump and sprint tests have been used to assess neuromuscular fatigue, but the test with optimal validity remains to be established. The current investigation examined the suitability of vertical jump (countermovement jump [CMJ], squat jump [SJ], drop jump [DJ]) and 20-m sprint (SPRINT) testing for neuromuscular fatigue detection. On 6 separate occasions, 11 male team-sport athletes performed 6 CMJ, SJ, DJ, and 3 SPRINT trials. Repeatability was determined on the first 3 visits, with subsequent 3 visits (0-, 24-, and 72-hour postexercise) following a fatiguing Yo-Yo running protocol. SPRINT performance was most repeatable (mean coefficient of variation ≤2%), whereas DJ testing (4.8%) was significantly less repeatable than CMJ (3.0%) and SJ (3.5%). Each test displayed large decreases at 0-hour (33 of 49 total variables; mean effect size = 1.82), with fewer and smaller decreases at 24-hour postexercise (13 variables; 0.75), and 72-hour postexercise (19 variables; 0.78). SPRINT displayed the largest decreases at 0-hour (3.65) but was subsequently unchanged, whereas SJ performance recovered by 72-hour postexercise. In contrast, CMJ and DJ performance displayed moderate (12 variables; 1.18) and small (6 variables; 0.53) reductions at 72-hour postexercise, respectively. Consequently, the high repeatability and immediate and prolonged fatigue-induced changes indicated CMJ testing as most suitable for neuromuscular fatigue monitoring.

  11. High performance image processing of SPRINT

    SciTech Connect

    DeGroot, T.

    1994-11-15

    This talk will describe computed tomography (CT) reconstruction using filtered back-projection on SPRINT parallel computers. CT is a computationally intensive task, typically requiring several minutes to reconstruct a 512x512 image. SPRINT and other parallel computers can be applied to CT reconstruction to reduce computation time from minutes to seconds. SPRINT is a family of massively parallel computers developed at LLNL. SPRINT-2.5 is a 128-node multiprocessor whose performance can exceed twice that of a Cray-Y/MP. SPRINT-3 will be 10 times faster. Described will be the parallel algorithms for filtered back-projection and their execution on SPRINT parallel computers.

  12. Importance of mitochondrial haplotypes and maternal lineage in sprint performance among individuals of West African ancestry.

    PubMed

    Deason, M; Scott, R; Irwin, L; Macaulay, V; Fuku, N; Tanaka, M; Irving, R; Charlton, V; Morrison, E; Austin, K; Pitsiladis, Y P

    2012-04-01

    Mitochondrial DNA (mtDNA) is inherited solely along the matriline, giving insight into both ancestry and prehistory. Individuals of sub-Saharan ancestry are overrepresented in sprint athletics, suggesting a genetic advantage. The purpose of this study was to compare the mtDNA haplogroup data of elite groups of Jamaican and African-American sprinters against respective controls to assess any differences in maternal lineage. The first hypervariable region of mtDNA was haplogrouped in elite Jamaican athletes (N=107) and Jamaican controls (N=293), and elite African-American athletes (N=119) and African-American controls (N=1148). Exact tests of total population differentiation were performed on total haplogroup frequencies. The frequency of non-sub-Saharan haplogroups in Jamaican athletes and Jamaican controls was similar (1.87% and 1.71%, respectively) and lower than that of African-American athletes and African-American controls (21.01% and 8.19%, respectively). There was no significant difference in total haplogroup frequencies between Jamaican athletes and Jamaican controls (P=0.551 ± 0.005); however, there was a highly significant difference between African-American athletes and African-American controls (P<0.001). The finding of statistically similar mtDNA haplogroup distributions in Jamaican athletes and Jamaican controls suggests that elite Jamaican sprinters are derived from the same source population and there is neither population stratification nor isolation for sprint performance. The significant difference between African-American sprinters and African-American controls suggests that the maternal admixture may play a role in sprint performance.

  13. Efficacy of a Four-Week Uphill Sprint Training Intervention in Field Hockey Players.

    PubMed

    Jakeman, John R; McMullan, Judith; Babraj, John A

    2016-10-01

    Jakeman, JR, McMullan, J, and Babraj, JA. Efficacy of a four-week uphill sprint training intervention in field hockey players. J Strength Cond Res 30(10): 2761-2766, 2016-Current evidence increasingly suggests that very short, supramaximal bouts of exercise can have significant health and performance benefits. Most research conducted in the area, however, uses laboratory-based protocols, which can lack ecological validity. The purpose of this study was to examine the effects of a high-intensity sprint training program on hockey-related performance measures. Fourteen semiprofessional hockey players either completed a 4-week high-intensity training (HIT) intervention, consisting of a total of 6 sessions of HIT, which progressively increased in volume (n = 7), or followed their normal training program (Con; n = 7). Straight-line sprint speed, with and without a hockey stick and ball, and slalom sprint speed, with and without a hockey stick and ball, were used as performance indicators. Maximal sprint speed over 22.9 m was also assessed. On completion of the 4-week intervention, straight-line sprint speed improved significantly in the HIT group (∼3%), with no changes in performance for the Con group. Slalom sprint speed, both with and without a hockey ball, was not significantly different after the training program in either group. Maximal sprint speed improved significantly (12.1%) in the HIT group, but there was no significant performance change in the Con group. The findings of this study indicate that a short period of HIT can significantly improve hockey-related performance measures and could be beneficial to athletes and coaches in field settings.

  14. Validity and reliability of hand and electronic timing for 40-yd sprint in college football players.

    PubMed

    Mann, J Bryan; Ivey, Pat J; Brechue, William F; Mayhew, Jerry L

    2015-06-01

    The 40-yd sprint is the premier event for evaluating sprint speed among football players at all competitive levels. Some questions remain concerning the validity of hand timing compared with electronic timing, as well as the lack of assessment and reliability of each method. The purpose of this study was to evaluate the validity of hand timing by experienced and novice timers compared with electronic timing and to establish the reliability and smallest worthwhile difference (SWD) of each method for the 40-yd sprint. National Collegiate Athletic Association (NCAA) Division I college football players (n = 81) ran two 40-yd sprint trials, with each being timed electronically (touch pad start and infrared beam stop) and with hand-held stopwatches by 2 experienced and 4 novice timers. There was no significant difference between trials timed electronically or by experienced and novice timers. Hand timing (experienced = 4.90 ± 0.34 seconds; novice = 4.86 ± 0.33 seconds) produced a significantly faster 40-yd sprint time than electronic timing (5.12 ± 0.35 seconds) by 0.22 ± 0.07 and 0.26 ± 0.08 seconds, respectively. Relative reliability was extremely high for all comparisons with intraclass correlation coefficient >0.987. The SWD was 0.12 seconds with electronic timing and 0.14 seconds with hand timing. In conclusion, hand timing produces faster sprint times than electronic timing in college football players, independent of timer experience. Repeated 40-yd sprint trials have high relative reliability regardless of timing method. A meaningful change in 40-yd sprint performance is dependent on timing method used.

  15. Effects of resisted sprint training on acceleration in professional rugby union players.

    PubMed

    West, Daniel J; Cunningham, Dan J; Bracken, Richard M; Bevan, Huw R; Crewther, Blair T; Cook, Christian J; Kilduff, Liam P

    2013-04-01

    The use of weighted sled towing as a training tool to improve athlete acceleration has received considerable attention; however, its effectiveness for developing acceleration is equivocal. This study compared the effects of combined weighted sled towing and sprint training against traditional sprint training on 10 and 30 m speed in professional rugby union players (n = 20). After baseline testing of 10 and 30 m speed, participants were assigned to either the combined sled towing and sprint training (SLED) or traditional sprint training (TRAD) groups, matched for 10-m sprint times. Each group completed 2 training sessions per week for 6 weeks, with performance reassessed post-training. Both training programmes improved participants' 10 and 30 m speed (p < 0.001), but the performance changes (from pre to post) in 10 m (SLED -0.04 ± 0.01 vs. TRAD -0.02 ± 0.01 seconds; p < 0.001) and 30 m (SLED -0.10 ± 0.03 vs. TRAD -0.05 ± 0.03 seconds; p = 0.003) sprint times were significantly greater in the SLED training group. Similarly, the percent change within the SLED group for the 10 m (SLED -2.43 ± 0.67 vs. TRAD -1.06 ± 0.80 seconds; p = 0.003) and 30 m (SLED -2.46 ± 0.63 vs. TRAD -1.15 ± 0.72 seconds; p = 0.003) tests were greater than the TRAD group. In conclusion, sprint training alone or combined with weighted sled towing can improve 10 and 30 m sprint times; however, the latter training method promoted greater improvements in a group of professional rugby players.

  16. Postactivation Potentation Effects From Accommodating Resistance Combined With Heavy Back Squats on Short Sprint Performance.

    PubMed

    Wyland, Timothy P; Van Dorin, Joshua D; Reyes, G Francis Cisco

    2015-11-01

    Applying accommodating resistance combined with isoinertial resistance has been demonstrated to be effective in improving neuromuscular attributes important for sport performance. The main purpose of this study was to determine whether short sprints can be acutely enhanced after several sets of back squats with or without accommodating resistance. Twenty recreationally resistance-trained males (age: 23.3 ± 4.4 years; height: 178.9 ± 6.5 cm; weight: 88.3 ± 10.8 kg) performed pre-post testing on 9.1-m sprint time. Three different interventions were implemented in randomized order between pre-post 9.1-m sprints. On 3 separate days, subjects either sat for 5 minutes (CTRL), performed 5 sets of 3 repetitions at 85% of their 1 repetition maximum (1RM) with isoinertial load (STND), or performed 5 sets of 3 repetitions at 85% of their 1RM, with 30% of the total resistance coming from elastic band tension (BAND) between pre-post 9.1-m sprint testing. Posttesting for 9.1-m sprint time occurred immediately after the last set of squats (Post-Immediate) and on every minute for 4 minutes after the last set of squats (Post-1min, Post-2min, Post-3min, and Post-4min). Repeated-measures analysis of variance statistical analyses revealed no significant changes in sprint time across posttesting times during the CTRL and STND condition. During the BAND condition, sprint time significantly decreased from Post-Immediate to Post-4min (p = 0.002). The uniqueness of accommodating resistance could create an optimal postactivation potentiation effect to increase neuromuscular performance. Coaches and athletes can implement heavy accommodating resistance exercises to their warm-up when improving acute sprint time is desired.

  17. Effect of Beta alanine and sodium bicarbonate supplementation on repeated-sprint performance.

    PubMed

    Ducker, Kagan J; Dawson, Brian; Wallman, Karen E

    2013-12-01

    This study aimed to investigate if combining beta alanine (BA) and sodium bicarbonate (NaHCO3) supplementation could lead to enhanced repeated-sprint performance in team-sport athletes, beyond what is possible with either supplement alone. Participants (n = 24) completed duplicate trials of a repeated-sprint test (3 sets; 6 × 20 m departing every 25 seconds, 4 minutes active recovery between sets) and were then allocated into 4 groups as follows: BA only (n = 6; 28 days BA, acute sodium chloride placebo); NaHCO3 only (n = 6; 28 days glucose placebo, acute NaHCO3); BA/NaHCO3 (n = 6; 28 days BA, acute NaHCO3); placebo only (n = 6; 28 days glucose placebo, acute sodium chloride placebo), then completed duplicate trials postsupplementation. Sodium bicarbonate alone resulted in moderate effect size (d = 0.40-0.71) and "likely" and "very likely" benefit for overall total sprint times (TST) and for each individual set and for first sprint (sets 2 and 3) and best sprint time (sets 2 and 3). Combining BA and NaHCO3 resulted in "possible" to "likely" benefits for overall TST and for sets 2 and 3. First sprint (set 3) and best sprint time (sets 2 and 3) also showed "likely" benefit after this trial. The BA and placebo groups showed no differences in performance after supplementation. In conclusion, these results indicate that supplementation with acute NaHCO3 improved repeated-sprint performance more than either a combination of NaHCO3 and BA or BA alone.

  18. Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat.

    PubMed

    Wilk, Boguslaw; Timmons, Brian W; Bar-Or, Oded

    2010-12-01

    We determined whether beverage flavoring and composition would stimulate voluntary drink intake, prevent dehydration, and maintain exercise performance in heat-acclimated adolescent males running in the heat. Eight adolescent (age, 13.7 ± 1.1 years) runners (peak oxygen uptake, 59.5 ± 4.0 mL·kg-1·min-1) underwent at least four 80-min exercise heat-acclimation sessions before completing 3 experimental sessions. All sessions were performed at 30 °C and 60%-65% relative humidity. Each experimental session consisted of five 15-min treadmill runs at a speed eliciting 65% peak oxygen uptake, with a 5 min rest prior to each run. Ten minutes after the final run, a time to exhaustion test was performed at a speed eliciting 90% peak oxygen uptake. Counterbalanced experimental sessions were identical, except for fluid intake, which consisted of tap water (W), flavored water (FW), and FW with 6% carbohydrate and 18 mmol·L-1 NaCl (CNa) consumed ad libitum. Fluid intake and body weight were monitored to calculate dehydration. Voluntary fluid intake was similar to fluid losses in W (1032 ± 130 vs. 1340 ± 246 g), FW (1086 ± 86 vs. 1451 ± 253 g), and CNa (1259 ± 119 vs. 1358 ± 234 g). As a result, significant dehydration was avoided in all trials (-0.45% ± 0.68% body weight in W, -0.66% ± 0.50% body weight in FW, and -0.13% ± 0.71% body weight in CNa). Core temperature increased by ~1 °C during exercise, but was not different between trials. Time to exhaustion was not different between trials and averaged 8.8 ± 1.7 min. Under exercise conditions more closely reflecting real-life situations, heat-acclimatized adolescent male runners can appropriately gauge fluid intake regardless of the type of beverage made available, resulting in consistency in exercise performance. PMID:21164555

  19. SIXTY SECONDS OF FOAM ROLLING DOES NOT AFFECT FUNCTIONAL FLEXIBILITY OR CHANGE MUSCLE TEMPERATURE IN ADOLESCENT ATHLETES

    PubMed Central

    Jones, Thomas W.; Horobeanu, Cosmin; Turner, Anthony P.; Sproule, John

    2016-01-01

    Background Physiotherapists and other practitioners commonly prescribe foam rolling as an intervention, but the mechanistic effects of this intervention are not known. Purpose The aim of this investigation was to establish if a single bout of foam rolling affects flexibility, skeletal muscle contractility and reflected temperature. Methods Twelve adolescent male squash players were evaluated on two separate occasions (treatment and control visits) and were tested on both legs for flexibility of the hip flexors and quadriceps, muscle contractility (as measured by tensiomyography) and temperature of the quadriceps (assessed via thermography) at repeated time points pre- and post a 60s rolling intervention (pre-, immediately post, 5, 10, 15, and 30 minutes post). They rolled one leg on the treatment visit and did not perform rolling on the control visit. Results The main outcome measure was the flexibility of hip flexor and quadriceps at repeated time points up to 30 minutes post intervention. The average foam rolling force was 68% of subject's body weight. This force affected the combination of hip and quadriceps flexibility (p = 0.03; 2.4 degrees total increase with foam rolling) but not each muscle independently (p = 0.05 – 0.98) following a single 60s bout. Muscle contractility is not affected (p = 0.09 – 0.93) and temperature is not increased by foam rolling across time points (p = 0.19). Conclusions A single sixty-second bout of rolling applied to the quadriceps induces a small significant change in flexibility that is of little practical relevance, while muscle contractility and temperature remain unchanged. Investigation of larger doses of rolling is merited in athletic populations to justify current practice. Level of Evidence 2c PMID:27757289

  20. Using self-determination theory to explain sport persistence and dropout in adolescent athletes.

    PubMed

    García Calvo, Tomás; Cervelló, Eduardo; Jiménez, Ruth; Iglesias, Damián; Moreno Murcia, Juan Antonio

    2010-11-01

    Motivational characteristics are influential in shaping adolescents' desire to persist in sport or to discontinue their sport participation. Self-determination theory (Deci & Ryan, 2000) was utilized as the theoretical framework for this study. This theory examines whether sustained participatory involvement, defined as continued participation in the sport through the next year, was influenced by individuals' self-determined motivation and by the fulfillment of the three basic psychological needs of autonomy, competence, and relatedness. Four hundred ninety two soccer players between the ages of 13 and 17 years comprised the sample. Results indicated sport dropout was explained by higher levels of amotivation, external regulation, and introjected regulation and by lower satisfaction of relatedness and autonomy needs. The findings of this study contribute to the knowledge base on sport dropout as they supported many of self-determination theory.

  1. The child and adolescent athlete: a review of three potentially serious injuries

    PubMed Central

    2014-01-01

    The increased participation of children and adolescents in organized sports worldwide is a welcome trend given evidence of lower physical fitness and increased prevalence of overweight in this population. However, the increased sports activity of children from an early age and continued through the years of growth, against a background of their unique vulnerability to injury, gives rise to concern about the risk and severity of injury. Three types of injury–anterior cruciate ligament (ACL) injury, concussion, and physeal injury – are considered potentially serious given their frequency, potential for adverse long-term health outcomes, and escalating healthcare costs. Concussion is probably the hottest topic in sports injury currently with voracious media coverage and exploding research interest. Given the negative cognitive effects of concussion, it has the potential to have a great impact on children and adolescents during their formative years and potentially impair school achievement and, if concussion management is not managed appropriately, there can be long term negative impact on cognitive development and ability to resume sports participation. Sudden and gradual onset physeal injury is a unique injury to the pediatric population which can adversely affect growth if not managed correctly. Although data are lacking, the frequency of stress-related physeal injury appears to be increasing. If mismanaged, physeal injuries can also lead to long-term complications which could negatively affect ability to participate in sports. Management of ACL injuries is an area of controversy and if not managed appropriately, can affect long-term growth and recovery as well as the ability to participate in sports. This article considers the young athlete’s vulnerability to injury, with special reference to ACL injury, concussion, and physeal injury, and reviews current research on epidemiology, diagnosis, treatment, and prevention of these injury types. This article is

  2. Injuries to the Young Athlete.

    ERIC Educational Resources Information Center

    Sandusky, Jane C.

    A review of literature on the incidence and nature of injuries to young athletes is presented on the topics of: (1) physiological characteristics of preadolescents, adolescents, and young adults; (2) musculo-skeletal changes in the growing athlete; (3) epiphyseal injuries and their potential for resulting in temporary or permanent impairment; (4)…

  3. CNTFR Genotype and Sprint/power Performance: Case-control Association and Functional Studies.

    PubMed

    Miyamoto-Mikami, E; Fujita, Y; Murakami, H; Ito, M; Miyachi, M; Kawahara, T; Fuku, N

    2016-05-01

    The aim of this study was to investigate whether rs41274853 in the 3'-untranslated region of the ciliary neurotrophic factor receptor gene (CNTFR) is associated with elite sprint/power athletic status and assess its functional significance. A total of 211 Japanese sprint/power track and field athletes (62 international, 72 national, and 77 regional athletes) and 814 Japanese controls were genotyped at rs41274853. Luciferase reporter assay was conducted to investigate whether this C-to-T polymorphism affects binding of microRNA miR-675-5p to this region. The TT genotype was significantly more frequent among international sprint/power athletes (19.4%) than in the controls after Bonferroni correction (7.9%, P=0.036, OR=2.81 [95% CI: 1.43-5.55]). Furthermore, in non-athletic young/middle-aged men (n=132), TT genotype carriers exhibited significantly greater leg extension power (26.6±5.4 vs. 24.0±5.4 W/kg BW, P=0.019) and vertical jump performance (50.1±6.9 vs. 47.9±7.5 cm, P=0.047) than the CC+CT genotype carriers. Reporter assays revealed that the miR-675-5p binds to this polymorphic region within the CNTFR mRNA, irrespective of the rs41274853 allele present. Although the functional significance of the rs41274853 polymorphism remains unclear, the CNTFR is one of the candidate genes contributing to sprint/power performance. PMID:26837930

  4. CNTFR Genotype and Sprint/power Performance: Case-control Association and Functional Studies.

    PubMed

    Miyamoto-Mikami, E; Fujita, Y; Murakami, H; Ito, M; Miyachi, M; Kawahara, T; Fuku, N

    2016-05-01

    The aim of this study was to investigate whether rs41274853 in the 3'-untranslated region of the ciliary neurotrophic factor receptor gene (CNTFR) is associated with elite sprint/power athletic status and assess its functional significance. A total of 211 Japanese sprint/power track and field athletes (62 international, 72 national, and 77 regional athletes) and 814 Japanese controls were genotyped at rs41274853. Luciferase reporter assay was conducted to investigate whether this C-to-T polymorphism affects binding of microRNA miR-675-5p to this region. The TT genotype was significantly more frequent among international sprint/power athletes (19.4%) than in the controls after Bonferroni correction (7.9%, P=0.036, OR=2.81 [95% CI: 1.43-5.55]). Furthermore, in non-athletic young/middle-aged men (n=132), TT genotype carriers exhibited significantly greater leg extension power (26.6±5.4 vs. 24.0±5.4 W/kg BW, P=0.019) and vertical jump performance (50.1±6.9 vs. 47.9±7.5 cm, P=0.047) than the CC+CT genotype carriers. Reporter assays revealed that the miR-675-5p binds to this polymorphic region within the CNTFR mRNA, irrespective of the rs41274853 allele present. Although the functional significance of the rs41274853 polymorphism remains unclear, the CNTFR is one of the candidate genes contributing to sprint/power performance.

  5. Effects of functional exercises in the warm-up on sprint performances.

    PubMed

    Sander, Andre; Keiner, Michael; Schlumberger, Andreas; Wirth, Klaus; Schmidtbleicher, Dietmar

    2013-04-01

    The process of warming up prepares athletes for subsequent stress and increases their level of performance. Functional exercises are often included in warm-up programs for power sports, although a positive effect of functional exercises has not been confirmed. The aim of this study was to measure a possible effect of functional exercises on sprint performance included in a warm-up program. A total of 121 elite youth soccer players between 13 and 18 years of age participated in this study and performed 2 different warm-up programs. The first program (NWP) consisted of 5 minutes of nonspecific running, coordination exercises, stretching, and acceleration runs. The second program (WPS) was the same with additional functional exercises. The subjects were tested performing linear sprints of approximately 30 m and change-of-direction sprints of approximately 10 m. The t-test for dependent samples showed significant differences between the groups for each segment of the linear sprint (p < 0.01 for 5 m; p < 0.001 for 10, 15, 20, 25, and 30 m); however, the effect sizes are small. Also, in the change-of-direction sprint, the t-test showed significant differences between the groups (p < 0.01 for 10 m left, 10 m right; p < 0.001 for 5 m right). These effect sizes are also small. In the change-of-direction sprint time for 5 m left, the data showed no significant differences between the groups. The results show no effects of functional exercises on sprint performance that are implemented in addition to a general warm-up. It appears that a general warm-up program, such as the NWP, generates sufficient activation of the performance-limiting muscles for sprint performance. Functional exercises did not lead to a supplemental activation with a positive effect on sprint performance. Therefore, a warm-up for sprint performance should contain nonspecific running, coordination exercises, stretching exercises, and acceleration runs. These components lead to sufficient activation of the

  6. Repair of Acute-on-Chronic Subscapularis Insufficiency in an Adolescent Athlete.

    PubMed

    Gornitzky, Alex L; Potty, Anish G R; Carey, James L; Ganley, Theodore J

    2015-09-01

    A 13-year-old right-hand-dominant skeletally immature boy presented to the authors' clinic after being blocked during an overhead dodgeball throw and hearing an abrupt "pop" in the shoulder. He had pain in the subdeltoid region that was most prominent during sports-related activity, particularly throwing. The patient had nonoperative management of a lesser tuberosity avulsion fracture 1 year earlier after a similar injury that occurred during a basketball game. He had returned to normal sporting activity 2 months before the most recent injury. Repeat advanced imaging showed an avulsion fracture of the subscapularis tendon, with a significantly retracted 2-cm component as well as a less retracted component, suggesting acute-on-chronic injury. Given this retraction and the symptoms during throwing, the patient was counseled that surgical management would best facilitate an asymptomatic return to sports-related activity. This case showed acute-on-chronic subscapularis tendon insufficiency with avulsion of the lesser tuberosity and significant retraction of the subscapularis tendon without tearing, a rare injury pattern in adolescents. For fixation of the avulsed lesser tuberosity fracture, an open approach technique was used in which SpeedBridge (Arthrex, Naples, Florida) sutures were passed behind the bone fragment. Four anchors were placed medial and lateral to the subscapularis insertion points to create a knotless double-row footprint. Compared with the published literature, this method of subscapularis fixation offered secure anatomic repair in a time-efficient, user-friendly manner.

  7. Response of parathyroid hormone to anaerobic exercise in adolescent female athletes.

    PubMed

    Takada, H; Washino, K; Nagashima, M; Iwata, H

    1998-02-01

    It has been shown that moderate exercise suppresses parathyroid hormone (PTH) secretion, while strenuous exercise is apt to induce continuous secretion, which has a negative effect on bone mineral densities (BMD). The present study investigated a typical response of PTH to brief exercise. The study group comprised six adolescent female basketball players whose BMD were within normal limits. Maximal anaerobic power by three-step cycling was loaded on each subject. The first blood sample was drawn 30 min prior to testing test, the second was immediately following, the third was 15 min after, and the fourth was 30 min after. The proportional change in plasma volume was -11.5% immediately following (P < 0.05), +2.1% 15 min after, and +5.5% at 30 min after exercise (P < 0.05). The expected value was calculated on the assumption of no effect, except changes in plasma volume, by exercise. The measured values of PTH and calcium (Ca) immediately after exercise were lower than each of the expected values (P < 0.05 for both). At 15 min after, there was no significant difference between expected and measured values of PTH, Ca and magnesium (Mg), respectively. At 30 min after, the measured value of Ca and Mg was higher than each expected value (P < 0.05 for both). It was concluded that PTH secretion is suppressed transiently immediately after maximal anaerobic exercise and is then stimulated during the recovery time in normal BMD subjects.

  8. Association analysis of the ACTN3 R577X polymorphism and complex quantitative body composition and performance phenotypes in adolescent Greeks.

    PubMed

    Moran, Colin N; Yang, Nan; Bailey, Mark E S; Tsiokanos, Athanasios; Jamurtas, Athanasios; MacArthur, Daniel G; North, Kathryn; Pitsiladis, Yannis P; Wilson, Richard H

    2007-01-01

    The functional allele (577R) of ACTN3, which encodes human alpha-actinin-3, has been reported to be associated with elite athletic status and with response to resistance training, while the nonfunctional allele (577X) has been proposed as a candidate metabolically thrifty allele. In a study of 992 adolescent Greeks, we show that there is a significant association (P=0.003) between the ACTN3 R577X polymorphism and 40 m sprint time in males that accounts for 2.3% of phenotypic variance, with the 577R allele contributing to faster times in an additive manner. The R577X polymorphism is not associated with other power phenotypes related to 40 m sprint, nor with an endurance phenotype. Furthermore, the polymorphism is not associated with obesity-related phenotypes in our population, suggesting that the 577X allele is not a thrifty allele, and thus the persistence of this null allele must be explained in other terms.

  9. Relationships between ground reaction force impulse and kinematics of sprint-running acceleration.

    PubMed

    Hunter, Joseph P; Marshall, Robert N; McNair, Peter J

    2005-02-01

    The literature contains some hypotheses regarding the most favorable ground reaction force (GRF) for sprint running and how it might be achieved. This study tested the relevance of these hypotheses to the acceleration phase of a sprint, using GRF impulse as the GRF variable of interest. Thirty-six athletes performed maximal-effort sprints from which video and GRF data were collected at the 16-m mark. Associations between GRF impulse (expressed relative to body mass) and various kinematic measures were explored with simple and multiple linear regressions and paired t-tests. The regression results showed that relative propulsive impulse accounted for 57% of variance in sprint velocity. Relative braking impulse accounted for only 7% of variance in sprint velocity. In addition, the faster athletes tended to produce only moderate magnitudes of relative vertical impulse. Paired t-tests revealed that lower magnitudes of relative braking impulse were associated with a smaller touchdown distance (p < 0.01) and a more active touchdown (p < 0.001). Also, greater magnitudes of relative propulsive impulse were associated with a high mean hip extension velocity of the stance limb (p < 0.05). In conclusion, it is likely that high magnitudes of propulsion are required to achieve high acceleration. Although there was a weak trend for faster athletes to produce lower magnitudes of braking, the possibility of braking having some advantages could not be ruled out. Further research is required to see if braking, propulsive, and vertical impulses can be modified with specific training. This will also provide insight into how a change in one GRF component might affect the others.

  10. Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics

    PubMed Central

    Lockie, Robert G.; Jalilvand, Farzad; Callaghan, Samuel J.; Jeffriess, Matthew D.; Murphy, Aron J.

    2015-01-01

    This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time), and leg muscle performance (power, stiffness, strength). Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0–5, 5–10, and 0–10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ), a five-bound test (5BT), and the reactive strength index (RSI) defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson’s correlations and stepwise regression (p ≤ 0.05) determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40–0.54). The 5BT (5–10 and 0–10 m intervals) and RSI (5–10 m interval) also related to velocity (r = 0.37–0.47). Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0–5 m flight times (r = −0.46 to −0.51), and a longer 0–10 m step length (r = 0.38). Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r2 = 0.14–0.29) tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes. PMID:26839607

  11. Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics.

    PubMed

    Lockie, Robert G; Jalilvand, Farzad; Callaghan, Samuel J; Jeffriess, Matthew D; Murphy, Aron J

    2015-12-22

    This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time), and leg muscle performance (power, stiffness, strength). Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0-5, 5-10, and 0-10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ), a five-bound test (5BT), and the reactive strength index (RSI) defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson's correlations and stepwise regression (p ≤ 0.05) determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40-0.54). The 5BT (5-10 and 0-10 m intervals) and RSI (5-10 m interval) also related to velocity (r = 0.37-0.47). Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0-5 m flight times (r = -0.46 to -0.51), and a longer 0-10 m step length (r = 0.38). Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r(2) = 0.14-0.29) tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes.

  12. Approach to the Underperforming Athlete.

    PubMed

    Solomon, Mary L; Weiss Kelly, Amanda K

    2016-03-01

    Children and adolescents who participate in intense sports training may face physical and psychologic stresses. The pediatric health care provider can play an important role in monitoring an athlete's preparation by obtaining a proper sports history, assessing sleep hygiene, discussing nutrition and hydration guidelines, and evaluating physiologic causes of fatigue. Educating parents and athletes on the potential risks of high-intensity training, inadequate rest and sleep, and a poor diet may improve the athlete's performance and prevent symptoms of overtraining syndrome. Infectious mononucleosis must also be considered a cause of fatigue among adolescents. The signs and symptoms of overtraining and burnout are discussed in this article. PMID:27031317

  13. Free radicals and sprint exercise in humans.

    PubMed

    Morales-Alamo, D; Calbet, J A L

    2014-01-01

    Sprint exercise ability has been critical for survival. The remarkably high-power output levels attained during sprint exercise are achieved through strong activation of anaerobic, and to a lesser extent, aerobic energy supplying metabolic reactions, which generate reactive oxygen and nitrogen species (RONS). Sprint exercise may cause oxidative stress leading to muscle damage, particularly when performed in severe acute hypoxia. However, with training oxidative stress is reduced. Paradoxically, total plasma antioxidant capacity increases during the subsequent 2 h after a short sprint due to the increase in plasma urate concentration. The RONS produced during and immediately after sprint exercise play a capital role in signaling the adaptive response to sprint. Antioxidant supplementation blunts the normal AMPKα and CaMKII phosphorylation in response to sprint exercise. However, under conditions of increased glycolytic energy turnover and muscle acidification, as during sprint exercise in severe acute hypoxia, AMPKα phosphorylation is also blunted. This indicates that an optimal level of RONS-mediated stimulation is required for the normal signaling response to sprint exercise. Although RONS are implicated in fatigue, most studies convey that antioxidants do not enhance sprint performance in humans. Although currently controversial, it has been reported that antioxidant ingestion during training may jeopardize some of the beneficial adaptations to sprint training.

  14. Effect of surface-specific training on 20-m sprint performance on sand and grass surfaces.

    PubMed

    Binnie, Martyn J; Peeling, Peter; Pinnington, Hugh; Landers, Grant; Dawson, Brian

    2013-12-01

    This study compared the effect of an 8-week preseason conditioning program conducted on a sand (SAND) or grass (GRASS) surface on 20-m sprint performance. Twelve team-sport athletes were required to attend three 1-hour training sessions per week, including 2 surface-specific sessions (SAND, n = 6 or GRASS, n = 6) and 1 group session (conducted on grass). Throughout the training period, 20-m sprint times of all athletes were recorded on both sand and grass surfaces at the end of weeks 1, 4, and 8. Results showed a significant improvement in 20-m sand time in the SAND group only (p < 0.05), whereas 20-m grass time improved equally in both training subgroups (p < 0.05). These results suggest that surface-specificity is essential for 20-m speed improvements on sand and also that there is no detriment to grass speed gains when incorporating sand surfaces into a preseason program.

  15. Faster Futsal Players Perceive Higher Training Loads and Present Greater Decreases in Sprinting Speed During the Preseason.

    PubMed

    Nakamura, Fábio Y; Pereira, Lucas A; Rabelo, Felipe N; Ramirez-Campillo, Rodrigo; Loturco, Irineu

    2016-06-01

    Nakamura, FY, Pereira, LA, Rabelo, FN, Ramirez-Campillo, R, and Loturco, I. Faster futsal players perceive higher training loads and present greater decreases in sprinting speed during the preseason. J Strength Cond Res 30(6): 1553-1562, 2016-The aims of this study were to assess the speed-power characteristics of professional futsal players before and after a 9-week preseason and to explore possible relationships with internal training loads. Ten under-20 professional Brazilian futsal players performed unloaded (squat jump [SJ] and countermovement jump [CMJ]) and loaded (jump squat [JS]) jumps and a 20-m sprint test before and after the preseason. Weekly training loads as measured by session rating of perceived exertion (s-RPE) varied between 2,179 and 5,519 a.u. The magnitude-based inference statistics revealed that performance in the SJ, CMJ, and 20-m sprint very likely decreased (effect size [ES] = -0.64, -0.49, and -0.92, respectively), whereas mean propulsive power in the JS likely increased (ES = 0.42) in response to the preseason. The Pearson coefficient of correlation between velocity in the 20 m sprint test and s-RPE during the first 2 weeks of training was 0.66 (p ≤ 0.05) while no significant correlation was detected between total s-RPE (i.e., 9 weeks) and changes in the power-speed tests. The baseline 20-m sprint velocity was very largely and inversely (r = -0.90) correlated with the change in the 20-m sprint performance. In conclusion, futsal preseason training leads to impaired unloaded vertical jump and sprint test performance, with speed decreasing more in faster than slower players. In addition, because of the large correlation between baseline sprint ability and s-RPE, coaches are advised to assess sprinting performance at the beginning of the preseason to finely adjust the training stimuli to each athlete.

  16. Effects of a Body-Weight Supporting Kite on Sprint Running Kinematics in Well-Trained Sprinters.

    PubMed

    Kratky, Sascha; Buchecker, Michael; Pfusterschmied, Jürgen; Szekely, Csaba; Müller, Erich

    2016-01-01

    Data of elite sprinters indicate that faster athletes realize shorter ground contact times compared with slower individuals. Furthermore, the importance of the so-called "front side mechanics" for elite sprint performance is frequently emphasized by researchers and coaches. Recently, it was demonstrated that using a body-weight supporting kite during full-effort sprints in highly trained sprinters leads to a reduction in ground contact time. The aim of this study was to investigate possible negative effects of this body-weight supporting device on sprint running kinematics, which was not clarified in previous studies. Eleven well-trained Austrian sprinters performed flying 20-m sprints under 2 conditions: (a) free sprint (FS); and (b) body-weight supported sprint (BWS). Sprint cycle characteristics were recorded during the high-speed phase by a 16 camera 3D-system (Vicon), an optical acquisition system (Optojump-next), and a high-speed camera. Paired sample t-tests and Cohen's d effect size were used to determine differences between sprinting conditions. Compared with FS, BWS caused a decrease in ground contact time by 5.6% and an increase in air time by 5.5% (both p < 0.001), whereas stride length and rate remained unchanged. Furthermore, a reduced hip joint extension at and after take-off, an increased maximal hip joint flexion (i.e., high knee position), and a smaller horizontal distance of the touchdown to the center of gravity could be observed (all p < 0.01). These results indicate no negative effects on front side mechanics during BWS and that sprinting with a body-weight supporting kite seems to be a highly specific method to reduce ground contact time in well-trained sprinters.

  17. Optimal elastic cord assistance for sprinting in collegiate women soccer players.

    PubMed

    Bartolini, J Albert; Brown, Lee E; Coburn, Jared W; Judelson, Daniel A; Spiering, Barry A; Aguirre, Nick W; Carney, Keven R; Harris, Kenten B

    2011-05-01

    Overspeed exercises are commonly integrated into a training program to help athletes perform at a speed greater than what they are accustomed to when unassisted. However, the optimal assistance for maximal sprinting has not been determined. The purpose of this study was to determine the optimal elastic cord assistance for sprinting performance. Eighteen collegiate women soccer players completed 3 testing sessions, which consisted of a 5-minute warm-up, followed by 5 randomized experimental conditions of 0, 10, 20, 30, and 40% body weight assistance (BWA). In all BWA sessions, subjects wore a belt while attached to 2 elastic cords and performed 2 maximal sprints under each condition. Five minutes of rest was given between each sprint attempt and between conditions. Split times (0-5, 5-10, 10-15, 15-20, and 0-20 yd) for each condition were used for analysis. Results for 0-20 yd demonstrated a significant main effect for condition. Post hoc comparisons revealed that as BWA increased, sprint times decreased up to 30% BWA (0%: 3.20 ± 0.12 seconds; 10%: 3.07 ± 0.09 seconds; 20%: 2.96 ± 0.07 seconds; 30%: 2.81 ± 0.08 seconds; 40%: 2.77 ± 0.10 seconds); there was no difference between 30 and 40% BWA. There was also a main effect for condition when examining split times. Post hoc comparisons revealed that as BWA increased, sprint times decreased up to 30% BWA for distances up to 15 yd. These results demonstrate that 30% of BWA with elastic cords appears optimal in decreasing sprint times in collegiate women soccer players for distances up to 15 yd.

  18. Physical Determinants of Interval Sprint Times in Youth Soccer Players

    PubMed Central

    Amonette, William E.; Brown, Denham; Dupler, Terry L.; Xu, Junhai; Tufano, James J.; De Witt, John K.

    2014-01-01

    Relationships between sprinting speed, body mass, and vertical jump kinetics were assessed in 243 male soccer athletes ranging from 10–19 years. Participants ran a maximal 36.6 meter sprint; times at 9.1 (10 y) and 36.6 m (40 y) were determined using an electronic timing system. Body mass was measured by means of an electronic scale and body composition using a 3-site skinfold measurement completed by a skilled technician. Countermovement vertical jumps were performed on a force platform - from this test peak force was measured and peak power and vertical jump height were calculated. It was determined that age (r=−0.59; p<0.01), body mass (r=−0.52; p<0.01), lean mass (r=−0.61; p<0.01), vertical jump height (r=−0.67; p<0.01), peak power (r=−0.64; p<0.01), and peak force (r=−0.56; p<0.01) were correlated with time at 9.1 meters. Time-to-complete a 36.6 meter sprint was correlated with age (r=−0.71; p<0.01), body mass (r=−0.67; p<0.01), lean mass (r=−0.76; p<0.01), vertical jump height (r=−0.75; p<0.01), peak power (r=−0.78; p<0.01), and peak force (r=−0.69; p<0.01). These data indicate that soccer coaches desiring to improve speed in their athletes should devote substantive time to fitness programs that increase lean body mass and vertical force as well as power generating capabilities of their athletes. Additionally, vertical jump testing, with or without a force platform, may be a useful tool to screen soccer athletes for speed potential. PMID:25031679

  19. Prediction of 200-m sprint kayaking performance.

    PubMed

    van Someren, Ken A; Palmer, Garry S

    2003-08-01

    The aim of this study was to determine the anthropometric and physiological profile of 200-m sprint kayakers and to examine relationships with 200-m race performance. Twenty-six male kayakers who were categorised in two ability groups, international (Int) and national (Nat) level, underwent a battery of anthropometric and physiological tests and a 200-m race. Race time was significantly lower in Int than Nat (39.9 +/- 0.8 s and 42.6 +/- 0.9 s, respectively). Int demonstrated significantly greater measures of mesomorphy, biepycondylar humeral breadth, circumferences of the upper arm, forearm and chest, peak power and total work in a modified Wingate test, total work in a 2-min ergometry test, peak isokinetic power, and peak isometric force. Significant relationships were found between 200-m time and a number of anthropometric variables and anaerobic and dynamometric parameters. Stepwise multiple regression revealed that total work in the modified Wingate alone predicted 200-m race time (R2 = 0.53, SEE = 1.11 s) for all 26 subjects, while biepycondylar humeral breadth alone predicted race time (R2 = 0.54, SEE = 0.52 s) in Int. These results demonstrate that superior upper body dimensions and anaerobic capacities distinguish international-level kayakers from national-level athletes and may be used to predict 200-m performance.

  20. The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint

    PubMed Central

    Phillips, Shaun M.; Findlay, Scott; Kavaliauskas, Mykolas; Grant, Marie Clare

    2014-01-01

    output with the carbohydrate mouth rinse may come at a relative cost for the remainder of the sprint, evidenced by non-significantly lower mean power output and a greater fatigue index in the carbohydrate vs. placebo trial. Serial administration of a carbohydrate mouth rinse may be beneficial for sprint athletes as a method of performance enhancement that minimizes the risk of performance decrement through body mass increase and gastrointestinal disturbances associated with ingesting carbohydrate solutions. PMID:24790476

  1. The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint.

    PubMed

    Phillips, Shaun M; Findlay, Scott; Kavaliauskas, Mykolas; Grant, Marie Clare

    2014-05-01

    output with the carbohydrate mouth rinse may come at a relative cost for the remainder of the sprint, evidenced by non-significantly lower mean power output and a greater fatigue index in the carbohydrate vs. placebo trial.Serial administration of a carbohydrate mouth rinse may be beneficial for sprint athletes as a method of performance enhancement that minimizes the risk of performance decrement through body mass increase and gastrointestinal disturbances associated with ingesting carbohydrate solutions.

  2. Depression and Participation in Athletics among Military-Dependent High School Athletes during War

    ERIC Educational Resources Information Center

    Madler, Gerald L.

    2009-01-01

    This applied research study investigated depressive symptoms in military-dependent high school athletes vs. non-athletes who have a parent on active duty during Operation Iraqi Freedom/Operation Enduring Freedom. The sample consisted of 332 adolescents who either did or did not participate in athletic activities and either did or did not have a…

  3. Athlete's Foot

    MedlinePlus

    ... Home » Learn About Feet » Foot Health Information Athlete's Foot What is Athlete's Foot? Athlete's foot is a skin disease caused by a fungus, ... fungus growth. Not all fungus conditions are athlete's foot. Other conditions, such as disturbances of the sweat ...

  4. Evaluation of the running-based anaerobic sprint test as a measure of repeated sprint ability in collegiate-level soccer players.

    PubMed

    Keir, Daniel A; Thériault, Francis; Serresse, Olivier

    2013-06-01

    Repeated sprint ability (RSA) refers to an individual's ability to perform maximal sprints of short duration in succession with little recovery between sprints. The running-based anaerobic sprint test (RAST) has been adapted from the Wingate anaerobic test (WAnT) protocol as a tool to assess RSA and anaerobic power. The purpose of this study was to evaluate the relationship between performance variables and physiological responses obtained during the RAST and the WAnT using 8 collegiate-level soccer players. Participants performed a single trial of both the WAnT and the RAST. Breath-by-breath gas exchange was monitored throughout each trial, and blood lactate (BL) measures were recorded postexercise. The oxygen uptake (VO2) profile suggested that the RAST required greater contributions from aerobic metabolism although there was no difference in VO2peak (p < 0.05). Peak BL values were also similar between the RAST and the WAnT (p < 0.05). Neither peak physiological values nor performance variables (peak and mean power) were significantly correlated between protocols. The weak association in physiological responses indicates that different combinations of metabolic contributions exist between protocols, suggesting that individual performances on each test are not related in collegiate soccer players. Further studies on these relationships with players of other competitive levels and team sport athletes are warranted.

  5. The Prevalence of Obesity and Elevated Blood Pressure in Adolescent Student Athletes From the State of Mississippi

    PubMed Central

    Stiefel, Eric C.; Field, Larry; Replogle, William; McIntyre, Louis; Igboechi, Oduche; Savoie, Felix H.

    2016-01-01

    Background: Over the past 30 years, there has been a dramatic increase in the prevalence of childhood obesity and hypertension in the United States. The prevalence of these diagnoses among individuals participating in school-sanctioned sports has not been clearly defined. Purpose: To identify the prevalence of obesity and elevated blood pressure (BP) among student athletes and investigate associations between race, sex, type and number of sports played, and the prevalence of these diseases. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Pre–sports participation medical examinations (N = 7705) performed between 2009 and 2013 were reviewed to identify the prevalence of obesity and elevated BP and examine relationships between the type of sports played, participation in multiple sports versus a single sport, and the athlete’s body weight and body mass index (BMI). Results: The prevalence of obesity was 23.5%. There was a significant association (P < .001) between the number of sports played by the student and BMI. The risk of obesity among single-sport athletes was more than 2-fold the risk (relative risk [RR], 2.13) compared with ≥3-sport athletes and 1.42 times greater compared with 2-sport athletes (RR, 1.42). The prevalence of elevated BP was 21.2%. There was a significant association (P < .001) between the number of sports played by the student and elevated BP. The risk of elevated BP among single-sport athletes was 1.59 times greater (RR, 1.59) than ≥3-sport athletes and 1.30 times greater compared with 2-sport athletes (RR, 1.30). Finally, obese students were 2.40 times more likely to have elevated BP compared with nonobese students (P < .001). Conclusion: The result of this study confirms the progressive nature of the obesity epidemic and identifies the contribution of obesity to the worsening cardiometabolic profiles in student athletes. The study also identifies that participation in multiple sports and running sports decreases

  6. Influence of Dehydration on Intermittent Sprint Performance.

    PubMed

    Davis, Jon-Kyle; Laurent, C Matt; Allen, Kimberly E; Green, J Matt; Stolworthy, Nicola I; Welch, Taylor R; Nevett, Michael E

    2015-09-01

    This study examined the effects of dehydration on intermittent sprint performance and perceptual responses. Eight male collegiate baseball players completed intermittent sprints either dehydrated (DEHY) by 3% body mass or euhydrated (EU). Body mass was reduced through exercise in the heat with controlled fluid restriction occurring 1 day before the trial. Participants completed twenty-four 30-m sprints divided into 3 bouts of 8 sprints with 45 seconds of rest between each sprint and 3 minutes between each bout. Perceived recovery status (PRS) scale was recorded before the start of each trial. Heart rate (HR), ratings of perceived exertion (RPE) (0-10 OMNI scale), and perceived readiness (PR) scale were recorded after every sprint, and session RPE (SRPE) was recorded 20 minutes after completing the entire session. A 2 (condition) × 3 (bout of sprints) repeated-measures ANOVA revealed a significant main effect of condition on mean sprint time (p = 0.03), HR (p < 0.01), RPE (p = 0.01), and PR (p = 0.02). Post hoc tests showed significantly faster mean sprint times for EU vs. DEHY during the second (4.87 ± 0.29 vs. 5.03 ± 0.33 seconds; p = 0.01) and third bouts of sprints (4.91 ± 0.29 vs. 5.12 ± 0.44 seconds; p = 0.02). Heart rate was also significantly lower (p ≤ 0.05) for EU during the second and third bouts. Post hoc measures also showed significantly impaired (p ≤ 0.05) feelings of recovery (PRS) before exercise and increased (p ≤ 0.05) perceptual strain before each bout (PR) during the second and third bouts of repeated sprint work (i.e., RPE and PR) and after the total session (SRPE) in the DEHY condition. Dehydration impaired sprint performance, negatively altered perception of recovery status before exercise, and increased RPE and HR response.

  7. Physiological correlates of multiple-sprint ability and performance in international-standard squash players.

    PubMed

    Wilkinson, Michael; Cooke, Matthew; Murray, Stafford; Thompson, Kevin G; St Clair Gibson, Alan; Winter, Edward M

    2012-02-01

    From measures on a battery of fitness tests in elite-standard squash players on different tiers of a national performance program, we examined the relationships among test scores and player rank, and fitness factors important for squash-specific multiple-sprint ability. Thirty-one (20 men, 11 women) squash players from the England Squash performance program participated: n = 12 senior; n = 7 transition; n = 12 talented athlete scholarship scheme (TASS) players. In 1 test session and in a fixed order, the players completed a battery of tests to assess countermovement jump height, reactive strength, change-of-direction speed, and multiple-sprint ability on squash-specific tests and endurance fitness. Two-way analysis of variance compared senior, transition, and TASS players by sex on all measures except jump height where only senior and transition players were compared. Effect size (ES) was calculated for all comparisons. Pearson's correlation examined relationships among test scores and multiple-sprint ability. Spearman's ρ investigated relationships among test scores and players' rank in men and women separately. Regardless of sex, seniors outperformed TASS players on all except the endurance test (p < 0.05, ES at least 1.1). Seniors had better multiple-sprint ability than did transition players (p < 0.01, ES = 1.2). Transition outperformed TASS players on the reactive-strength test (p < 0.05, ES = 1.0). Men outperformed women in all tests at all performance program tiers (p < 0.05, ES at least 0.5). In men, rank was related to multiple-sprint ability, fastest-multiple-sprint-test repetition, and change-of-direction speed (ρ = 0.78, 0.86, 0.59, respectively). In women, rank was related to fastest multiple-sprint-test repetition (ρ = 0.65). In men and women, multiple-sprint ability was related to change-of-direction speed (r = 0.9 and 0.84) and fastest-multiple-sprint-test repetition (r = 0.96 for both) and to reactive strength in men (r = -0.71). The results

  8. Mechanical work accounts for sex differences in fatigue during repeated sprints.

    PubMed

    Billaut, François; Bishop, David J

    2012-04-01

    To investigate whether the larger reduction in mechanical work observed during repeated-sprint exercise (RSE) in men versus women represents a true, physiological sex dimorphism or is the consequence of the higher initial mechanical work performed by men. Male and female team-sport athletes (n = 35) performed 20, 5-s cycle sprints interspersed with 25 s of rest. Mechanical work and surface electromyograms (EMG) of four muscles were recorded in every sprint. Mechanical work achieved in one sprint (20.7%, P = 0.0006), total work accumulated over the 20 sprints (21.1%, P = 0.009) and percent work decrement (32.2%, P = 0.008) were larger in men than in women. When both sexes were plotted together, there was a positive relationship between the initial-sprint work and the work decrement across sprint repetitions (r = 0.89, P = 0.002). The RSE induced larger (P = 0.009) absolute EMG amplitude changes in men (-155.2 ± 60.3 mVs) than in women (-102.5 ± 45.1 mVs). Interestingly, in a subset of men and women (n = 7 per group) matched for initial-sprint work, the sex difference in percent work decrement (men: -29.5 ± 1.5%; women: -27.2 ± 3.2%; P = 0.72) and EMG changes (men: -17.7 ± 6.9% vs. women: -15.3 ± 7.1%; P = 0.69) no longer persisted. Results show that the proposed greater fatigue in men is likely to be a consequence of their greater absolute initial-sprint performance, rather than a sex difference in fatigue resistance per se. We conclude that, on the basis of the absolute mechanical work completed, women are not more fatigue resistant than men and use comparable muscle recruitment strategies to perform RSE.

  9. Physiological correlates of multiple-sprint ability and performance in international-standard squash players.

    PubMed

    Wilkinson, Michael; Cooke, Matthew; Murray, Stafford; Thompson, Kevin G; St Clair Gibson, Alan; Winter, Edward M

    2012-02-01

    From measures on a battery of fitness tests in elite-standard squash players on different tiers of a national performance program, we examined the relationships among test scores and player rank, and fitness factors important for squash-specific multiple-sprint ability. Thirty-one (20 men, 11 women) squash players from the England Squash performance program participated: n = 12 senior; n = 7 transition; n = 12 talented athlete scholarship scheme (TASS) players. In 1 test session and in a fixed order, the players completed a battery of tests to assess countermovement jump height, reactive strength, change-of-direction speed, and multiple-sprint ability on squash-specific tests and endurance fitness. Two-way analysis of variance compared senior, transition, and TASS players by sex on all measures except jump height where only senior and transition players were compared. Effect size (ES) was calculated for all comparisons. Pearson's correlation examined relationships among test scores and multiple-sprint ability. Spearman's ρ investigated relationships among test scores and players' rank in men and women separately. Regardless of sex, seniors outperformed TASS players on all except the endurance test (p < 0.05, ES at least 1.1). Seniors had better multiple-sprint ability than did transition players (p < 0.01, ES = 1.2). Transition outperformed TASS players on the reactive-strength test (p < 0.05, ES = 1.0). Men outperformed women in all tests at all performance program tiers (p < 0.05, ES at least 0.5). In men, rank was related to multiple-sprint ability, fastest-multiple-sprint-test repetition, and change-of-direction speed (ρ = 0.78, 0.86, 0.59, respectively). In women, rank was related to fastest multiple-sprint-test repetition (ρ = 0.65). In men and women, multiple-sprint ability was related to change-of-direction speed (r = 0.9 and 0.84) and fastest-multiple-sprint-test repetition (r = 0.96 for both) and to reactive strength in men (r = -0.71). The results

  10. Human torque velocity adaptations to sprint, endurance, or combined modes of training

    NASA Technical Reports Server (NTRS)

    Shealy, M. J.; Callister, R.; Dudley, G. A.; Fleck, S. J.

    1992-01-01

    We had groups of athletes perform sprint and endurance run training independently or concurrently for 8 weeks to examine the voluntary in vivo mechanical responses to each type of training. Pre- and posttraining angle-specific peak torque during knee extension and flexion were determined at 0, 0.84, 1.65, 2.51, 3.35, 4.19, and 5.03 radian.sec-1 and normalized for lean body mass. Knee extension torque in the sprint-trained group increased across all test velocities, the endurance-trained group increased at 2.51, 3.34, 4.19, and 5.03 radian.sec-1, and the group performing the combined training showed no change at any velocity. Knee flexion torque of the sprint and combined groups decreased at 0.84, 1.65, and 2.51 radian.sec-1. Knee flexion torque in the sprint-trained group also decreased at 0 radian.sec-1 and in the combined group at 3.34 radian.sec-1. Knee flexion torque in the endurance-trained group showed no change at any velocity of contraction. Mean knee flexion:extension ratios across the test velocities significantly decreased in the sprint-trained group. Knee extension endurance during 30 seconds of maximal contractions significantly increased in all groups. Only the sprint-trained group showed a significant increase in endurance of the knee flexors. These data suggest that changes in the voluntary in vivo mechanical characteristics of knee extensor and flexor skeletal muscles are specific to the type of run training performed.

  11. Effect of pre-performance lower-limb massage on thirty-meter sprint running.

    PubMed

    Goodwin, Jon E; Glaister, Mark; Howatson, Glyn; Lockey, Richard A; McInnes, Gillian

    2007-11-01

    Massage is a commonly utilized therapy within sports, frequently intended as an ergogenic aid prior to performance. However, evidence as to the efficacy of massage in this respect is lacking, and massage may in some instances reduce force production. The aim of this study was to investigate the effect of massage on subsequent 30-m sprint running performance. Male university level repeat sprint sports players volunteered for the study (n = 37). After each of 3 treatment conditions, subjects completed a standardized warm-up followed by three 30-m sprint trials in a counterbalanced crossover design. Treatment conditions were 15 minutes of lower-limb massage (M), 15 minutes of placebo ultrasound (PU), and rest (R). Thirty-meter sprint times were recorded (including 10-m split times) for the 3 trials under each condition. Best times at 10 m (M: 1.85 +/- 0.09 seconds, PU: 1.84 +/- 0.11 seconds, R: 1.83 +/- 0.10 seconds) and 30 m (M: 4.41 +/- 0.27 seconds, PU: 4.39 +/- 0.28 seconds, R: 4.39 +/- 0.28 seconds) were not significantly different (p > 0.05). There was no significant treatment, trial, or interaction effect for 10- or 30-m sprint times (p > 0.05). No difference was seen in the location of subjects' best times across the 3 trials (p > 0.05). Relative to placebo or control, the results of this study showed that a controlled 15-minute lower-limb massage administered prior to warm-up had no significant effect on subsequent 30-m sprint performance. Massage remains indicated prior to performance where other benefits, such as reduced muscle spasm and psychological stress, might be served to the athlete.

  12. Psychological Characteristics of Adolescent Steroid Users.

    ERIC Educational Resources Information Center

    Burnett, Kent F.; Kleiman, Mark E.

    1994-01-01

    Used Millon Adolescent Personality Inventory and Profile of Mood States to assess psychological characteristics in 72 adolescent males: 24 adolescent athletes who reported steroid use, 24 athletes with no steroid use, and 24 nonathletes. Although some personality variables differentiated between athletes and nonathletes, no personality variables…

  13. Athlete's Foot

    MedlinePlus

    Athlete's foot is a common infection caused by a fungus. It most often affects the space between the toes. ... skin between your toes. You can get athlete's foot from damp surfaces, such as showers, swimming pools, ...

  14. Athlete's Foot

    MedlinePlus

    ... type of tinea, athlete's foot. The Basics on Tinea Infections Tinea (pronounced: TIH-nee-uh) is the medical name ... or scalp, including athlete's foot, jock itch , and ringworm (despite its name, ringworm is not a worm). ...

  15. Factors that differentiate acceleration ability in field sport athletes.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Knight, Timothy J; Janse de Jonge, Xanne A K

    2011-10-01

    Speed and acceleration are essential for field sport athletes. However, the mechanical factors important for field sport acceleration have not been established in the scientific literature. The purpose of this study was to determine the biomechanical and performance factors that differentiate sprint acceleration ability in field sport athletes. Twenty men completed sprint tests for biomechanical analysis and tests of power, strength, and leg stiffness. The sprint intervals analyzed were 0-5, 5-10, and 0-10 m. The subjects were split into a faster and slower group based on 0- to 10-m velocity. A 1-way analysis of variance determined variables that significantly (p ≤ 0.05) distinguished between faster and slower acceleration. All subject data were then pooled for a correlation analysis to determine factors contributing most to acceleration. The results showed that 0- to 5-m (∼16% difference) and 0- to 10-m (∼11% difference) contact times for the faster group were significantly lower. Times to peak vertical and horizontal force during ground contact were lower for the faster group. This was associated with the reduced support times achieved by faster accelerators and their ability to generate force quickly. Ground contact force profiles during initial acceleration are useful discriminators of sprint performance in field sport athletes. For the strength and power measures, the faster group demonstrated a 14% greater countermovement jump and 48% greater reactive strength index. Significant correlations were found between velocity (0-5, 5-10, and 0-10 m) and most strength and power measures. The novel finding of this study is that training programs directed toward improving field sport sprint acceleration should aim to reduce contact time and improve ground force efficiency. It is important that even during the short sprints required for field sports, practitioners focus on good technique with short contact times.

  16. The force, power, and energy of the 100 meter sprint

    NASA Astrophysics Data System (ADS)

    Helene, O.; Yamashita, M. T.

    2010-03-01

    At the 2008 Summer Olympics in Beijing, Usain Bolt broke the world record for the 100 m sprint. Just one year later, at the 2009 World Championships in Athletics in Berlin he broke it again. A few months after Beijing, Eriksen et al. [Am. J. Phys. 77, 224-228 (2009)] studied Bolt's performance and predicted that Bolt could have run about one-tenth of a second faster, which was confirmed in Berlin. In this paper we extend the analysis of Eriksen et al. to model Bolt's velocity time dependence for the Beijing 2008 and Berlin 2009 records. We deduce the maximum force, the maximum power, and the total mechanical energy produced by Bolt in both races. Surprisingly, we conclude that all of these values were smaller in 2009 than in 2008.

  17. A Study To Determine the Effect of Resistance Training and Specificity Training on Sprint Times Compared to the Effect of Natural Growth Development of Middle School Age Students.

    ERIC Educational Resources Information Center

    Havens, Craig M.

    The purpose of this study was to determine how physical education teachers and coaches could best help students/athletes increase sprint speed, investigating whether running speed over short distances could be improved significantly through resistance training or specificity training for middle school age students. A total of 70 7th- and 8th-grade…

  18. Muscle coordination changes during intermittent cycling sprints.

    PubMed

    Billaut, François; Basset, Fabien A; Falgairette, Guy

    2005-06-01

    Maximal muscle power is reported to decrease during explosive cyclical exercises owing to metabolic disturbances, muscle damage, and adjustments in the efferent neural command. The aim of the present study was to analyze the influence of inter-muscle coordination in fatigue occurrence during 10 intermittent 6-s cycling sprints, with 30-s recovery through electromyographic activity (EMG). Results showed a decrease in peak power output with sprint repetitions (sprint 1 versus sprint 10: -11%, P<0.01) without any significant modifications in the integrated EMG. The timing between the knee extensor and the flexor EMG activation onsets was reduced in sprint 10 (sprint 1 versus sprint 10: -90.2 ms, P<0.05), owing to an earlier antagonist activation with fatigue occurrence. In conclusion, the maximal power output, developed during intermittent cycling sprints of short duration, decreased possibly due to the inability of muscles to maintain maximal force. This reduction in maximal power output occurred in parallel to changes in the muscle coordination pattern after fatigue. PMID:15862899

  19. What Research Tells the Coach About Sprinting.

    ERIC Educational Resources Information Center

    Dintiman, George B.

    This booklet on sprinting is divided into four chapters. Chapter 1 "Introduction," provides an analysis of the 100-meter dash, summarizes world records, and discusses the reliability of timing the sprint race. Chapter 2, "Describing the Sprinter," discusses the following topics: anatomical characteristics, flexibility, reaction, strength/power,…

  20. Elbow Trauma in the Athlete.

    PubMed

    Redler, Lauren H; Dines, Joshua S

    2015-11-01

    In caring for athletes, the physician must be able to accurately diagnose and appropriately treat all forms of elbow injuries. Traumatic injuries to the elbow are common in the athlete. The late cocking phase of throwing produces tremendous valgus stress on the elbow that can lead to medial epicondyle avulsion fractures in adolescents or rupture of the medial ulnar collateral ligament in skeletally mature overhead throwers, such as baseball pitchers and javelin throwers. Common traumatic elbow injuries suffered by athletes, surgical techniques for operative repair of these injuries, as well as postoperative rehabilitation protocols and the clinical results are presented.

  1. Estimation of temporal parameters during sprint running using a trunk-mounted inertial measurement unit.

    PubMed

    Bergamini, Elena; Picerno, Pietro; Pillet, Hélène; Natta, Françoise; Thoreux, Patricia; Camomilla, Valentina

    2012-04-01

    The purpose of this study was to identify consistent features in the signals supplied by a single inertial measurement unit (IMU), or thereof derived, for the identification of foot-strike and foot-off instants of time and for the estimation of stance and stride duration during the maintenance phase of sprint running. Maximal sprint runs were performed on tartan tracks by five amateur and six elite athletes, and durations derived from the IMU data were validated using force platforms and a high-speed video camera, respectively, for the two groups. The IMU was positioned on the lower back trunk (L1 level) of each athlete. The magnitudes of the acceleration and angular velocity vectors measured by the IMU, as well as their wavelet-mediated first and second derivatives were computed, and features related to foot-strike and foot-off events sought. No consistent features were found on the acceleration signal or on its first and second derivatives. Conversely, the foot-strike and foot-off events could be identified from features exhibited by the second derivative of the angular velocity magnitude. An average absolute difference of 0.005 s was found between IMU and reference estimates, for both stance and stride duration and for both amateur and elite athletes. The 95% limits of agreement of this difference were less than 0.025 s. The results proved that a single, trunk-mounted IMU is suitable to estimate stance and stride duration during sprint running, providing the opportunity to collect information in the field, without constraining or limiting athletes' and coaches' activities. PMID:22325976

  2. Physiological and Neuromuscular Response to a Simulated Sprint-Distance Triathlon: Effect of Age Differences and Ability Level.

    PubMed

    García-Pinillos, Felipe; Cámara-Pérez, José C; González-Fernández, Francisco T; Párraga-Montilla, Juan A; Muñoz-Jiménez, Marcos; Latorre-Román, Pedro Á

    2016-04-01

    This study aimed to describe the acute impact of a simulated sprint-distance triathlon at physiological and neuromuscular levels and to determine whether age and athletic performance influenced the response in triathletes. Nineteen triathletes performed a sprint-distance triathlon under simulated conditions. Cardiovascular response was monitored during the race. Rate of perceived exertion along with muscular performance parameters (countermovement jump [CMJ], squat jump [SJ], and handgrip strength test [HS]) were tested at pre- and posttest and during every transition, while a 20-m sprint test (S20m) was performed before and after the race. Blood lactate was recorded postrace. A repeated measures analysis of variance showed that the neuromuscular response-in terms of CMJ, SJ, and HS-was unchanged (p ≥ 0.05), while S20m performance was impaired at posttest (p < 0.001). A linear regression analysis showed that ΔCMJ predicted the overall race time (R = 0.226; p = 0.046). In addition, 2 cluster analyses (k-means) were performed by grouping according to athletic performance and age. Between-group comparison showed no significant differences in the impact of the race at either the physiological or the neuromuscular level. The results showed that muscular performance parameters were not impaired throughout the race despite high levels of fatigue reported. However, despite maintaining initial levels of muscle force after the race, the fatigue-induced changes in S20m were significant, which could reinforce the need to train sprint ability in endurance athletes. Finally, despite the differences in ability level or in age, the acute physiological and neuromuscular responses to a simulated sprint-distance triathlon were similar.

  3. Pars Injuries in Athletes.

    PubMed

    Oren, Jonathan H; Gallina, Jason M

    2016-03-01

    Pars injuries are common causes of low back pain in adolescent athletes. Workup traditionally has included lumbar radiographs with oblique views and single-photon emission computed tomography (SPECT). However, recent literature has demonstrated the accuracy of MRI as a diagnostic modality. Acute injuries may be amenable to bracing with the goal of a healed lesion. Most cases of spondylolysis will result in asymptomatic non-union, though pars repair is an option for symptomatic pars defects without spondylolisthesis. PMID:26977552

  4. CONSERVATIVE MANAGEMENT OF AN ISOLATED GRADE III LATERAL COLLATERAL LIGAMENT INJURY IN AN ADOLESCENT MULTI-SPORT ATHLETE: A CASE REPORT

    PubMed Central

    Haddad, M. Alex; Budich, Justin M.; Eckenrode, Brian J.

    2016-01-01

    ABSTRACT Study design Case report Background Isolated, grade III lateral collateral ligament knee injuries are an uncommon traumatic injury with little guidance available in the literature for conservative management and prognosis for return to sport. The purpose of this case report is to describe the clinical decision-making in both differential diagnosis and physical therapy management of an isolated grade III lateral collateral ligament sprain in an adolescent multi-sport high school athlete. Case Description A 16 year-old male, high school, multi-sport athlete (cross country, wrestling, track and field) sustained a traumatic knee injury during a wrestling match when his involved lower extremity was forcefully externally rotated by his opponent. Initial clinical presentation revealed pain and increased laxity with varus stress testing of the left knee, which was subsequently identified via MRI as a complete lateral collateral ligament rupture (grade III). A conservative physical therapy program was developed targeting the active and neuromuscular subsystems, theorized to compensate for the lack of an intact lateral collateral ligament. Outcomes The subject attended 18 visits of physical therapy over a period of 12 weeks. His rehabilitation program focused on functional strengthening of the posterolateral corner, enhancement of neuromuscular control, and graded progression to sports specific drills. Return to play decisions were based on a combination of lower extremity functional performance measures, condition specific outcome measures and subjective performance on sports specific tasks. At discharge from physical therapy, he reported 0/10 pain, scored a 76/80 on the Lower Extremity Functional Scale, and was able to return to competitive track and field events. Discussion Few descriptions in the literature exist for the conservative management of isolated, grade III lateral collateral ligament injuries. A program of selective functional strengthening

  5. On the performance of Usain Bolt in the 100 m sprint

    NASA Astrophysics Data System (ADS)

    Hernández Gómez, J. J.; Marquina, V.; Gómez, R. W.

    2013-09-01

    Many university texts on mechanics consider the effect of air drag force, using the slowing down of a parachute as an example. Very few discuss what happens when the drag force is proportional to both u and u2. In this paper we deal with a real problem to illustrate the effect of both terms on the speed of a runner: a theoretical model of the world-record 100 m sprint of Usain Bolt during the 2009 World Championships in Berlin is developed, assuming a drag force proportional to u and to u2. The resulting equation of motion is solved and fitted to the experimental data obtained from the International Association of Athletics Federations, which recorded Bolt's position with a laser velocity guard device. It is worth noting that our model works only for short sprints.

  6. THE ACUTE EFFECTS OF VARIOUS TYPES OF STRETCHING STATIC, DYNAMIC, BALLISTIC, AND NO STRETCH OF THE ILIOPSOAS ON 40‐YARD SPRINT TIMES IN RECREATIONAL RUNNERS

    PubMed Central

    Christensen, Scott D.; Perry, Craig; Hoover, Donald L.

    2012-01-01

    Background and Purpose: The potential adverse effects of static stretching on athletic performance are well documented, but still appears to be controversial, especially as they relates to sprinting. The prevalence of this practice is demonstrated by the number of competitive and recreational athletes who regularly engage in stretching immediately prior to sprinting with the mindset of optimizing their performance. The purpose of this study was to examine the effects of acute static, dynamic, and ballistic stretching, and no stretching of the iliopsoas muscle on 40‐yard sprint times in 18‐37 year‐old non‐competitive, recreational runners. Methods: Twenty‐five healthy recreational runners (16 male and 9 female) between the ages of 24 and 35 (Mean = 26.76 yrs., SD = 2.42 yrs.) completed this study. A repeated measures design was used, which consisted of running a 40‐yard sprint trial immediately following each of 4 different stretching conditions aimed at the iliopsoas muscle and lasting 1 minute each. The 4 conditions were completed in a randomized order within a 2‐week time period, allowing 48‐72 hours between each condition. Prior to each 40‐yard sprint trial, a 5‐minute walking warm‐up was performed at 3.5 mph on a treadmill. The subject then ran a baseline 40‐yard sprint. After a 10‐minute self‐paced walk, each subject performed one of the 4 stretching conditions (ballistic, dynamic, static, and no stretch) and then immediately ran a timed 40‐yard sprint. Results: There was a significant interaction between stretching conditions and their effects on sprint times, F(3,72) = 9.422, p<.0005. To break down this interaction, simple main effects were performed with 2 repeated measures ANOVAs and 4 paired t‐tests using a Bonferroni corrected alpha (α = .0083). There were no significant differences between the 4 pre‐condition times, p = 0.103 (Greenhouse‐Geisser) or the post‐condition times, p = 0.029. In the no stretch condition

  7. Association of the MTHFR 1298A>C (rs1801131) polymorphism with speed and strength sports in Russian and Polish athletes.

    PubMed

    Zarebska, Aleksandra; Ahmetov, Ildus I; Sawczyn, Stanislaw; Weiner, Alexandra S; Kaczmarczyk, Mariusz; Ficek, Krzysztof; Maciejewska-Karlowska, Agnieszka; Sawczuk, Marek; Leonska-Duniec, Agata; Klocek, Tomasz; Voronina, Elena N; Boyarskikh, Uljana A; Filipenko, Maksim L; Cieszczyk, Pawel

    2014-01-01

    It has been suggested that DNA hypomethylation because of poorer effectiveness of the 5,10-methylenetetrahydrofolate reductase (MTHFR) enzyme induces muscular growth. We hypothesised that the common, functional 1298A>C polymorphism in the MTHFR gene is associated with athletic status. To test this hypothesis, we investigated the distribution of the 1298A>C variant in Polish (n = 302) and Russian (n = 842) athletes divided into four groups: endurance, strength-endurance, sprint-strength and strength-endurance, as well as in 1540 control participants. We found different genotypes (the AC heterozygote advantage) and allele distributions among sprint-strength athletes and strength athletes than the groups of sedentary controls for each nationality. In the combined study, the allelic frequencies for the 1298C variant were 35.6% in sprint-strength athletes (OR 1.18 [1.02-1.36], P = 0.024 vs. controls) and 38.6% in strength athletes (OR 1.34 [1.10-1.64], P = 0.003 vs. controls). The results of the initial and repetition studies as well as the combined analysis suggest that the functional 1298A>C polymorphism in the MTHFR gene is associated with athletic status. The presence of the C allele seems to be beneficial in sprint-strength and strength athletes. It needs to be established whether and to what extent this effect is mediated by alteration in DNA methylation status.

  8. Two-Dimensional Video Analysis of Youth and Adolescent Pitching Biomechanics: A Tool For the Common Athlete.

    PubMed

    DeFroda, Steven F; Thigpen, Charles A; Kriz, Peter K

    2016-01-01

    Three-dimensional (3D) motion analysis is the gold standard for analyzing the biomechanics of the baseball pitching motion. Historically, 3D analysis has been available primarily to elite athletes, requiring advanced cameras, and sophisticated facilities with expensive software. The advent of newer technology, and increased affordability of video recording devices, and smartphone/tablet-based applications has led to increased access to this technology for youth/amateur athletes and sports medicine professionals. Two-dimensional (2D) video analysis is an emerging tool for the kinematic assessment and observational measurement of pitching biomechanics. It is important for providers, coaches, and players to be aware of this technology, its application in identifying causes of arm pain and preventing injury, as well as its limitations. This review provides an in-depth assessment of 2D video analysis studies for pitching, a direct comparison of 2D video versus 3D motion analysis, and a practical introduction to assessing pitching biomechanics using 2D video analysis.

  9. Two-Dimensional Video Analysis of Youth and Adolescent Pitching Biomechanics: A Tool For the Common Athlete.

    PubMed

    DeFroda, Steven F; Thigpen, Charles A; Kriz, Peter K

    2016-01-01

    Three-dimensional (3D) motion analysis is the gold standard for analyzing the biomechanics of the baseball pitching motion. Historically, 3D analysis has been available primarily to elite athletes, requiring advanced cameras, and sophisticated facilities with expensive software. The advent of newer technology, and increased affordability of video recording devices, and smartphone/tablet-based applications has led to increased access to this technology for youth/amateur athletes and sports medicine professionals. Two-dimensional (2D) video analysis is an emerging tool for the kinematic assessment and observational measurement of pitching biomechanics. It is important for providers, coaches, and players to be aware of this technology, its application in identifying causes of arm pain and preventing injury, as well as its limitations. This review provides an in-depth assessment of 2D video analysis studies for pitching, a direct comparison of 2D video versus 3D motion analysis, and a practical introduction to assessing pitching biomechanics using 2D video analysis. PMID:27618245

  10. Balance ability and athletic performance.

    PubMed

    Hrysomallis, Con

    2011-03-01

    jump height and sprint time. Balance ability was related to competition level for some sports, with the more proficient athletes displaying greater balance ability. There were significant relationships between balance ability and a number of performance measures. Evidence from prospective studies supports the notion that balance training can be a worthwhile adjunct to the usual training of non-elite athletes to enhance certain motor skills, but not in place of other conditioning such as resistance training. More research is required to determine the influence of balance training on the motor skills of elite athletes.

  11. 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.

  12. Stepping back to improve sprint performance: a kinetic analysis of the first step forwards.

    PubMed

    Frost, David M; Cronin, John B

    2011-10-01

    Using a step backward to initiate forward movement can increase force and power at push-off and improve sprint performance over short distances. However, it is not clear whether the benefit provided by this paradoxical step influences the mechanics of the first step forwards. Twenty-seven men of an athletic background performed maximal effort 5-m sprints from a standing start and employed a step forwards (parallel and split stance) or backwards (false) to initiate movement. Each sprint was started with an audio cue that also activated the timing gates. Three trials of each starting style were performed and movement (0 m), 2.5-, and 5-m times were recorded. An in-ground force plate placed at the 0-m mark measured the kinetic and temporal characteristics of the first step. Sprint times to 2.5 and 5 m were slower (p < 0.05) when a parallel start was used. No differences were seen in the normalized peak forces (vertical and horizontal) or the vertical impulse between starts, but the vertical mean force was 11 and 12% higher for the false and split starts, respectively. Surprisingly, the parallel start's impulse was significantly greater than that of the false (24%) and split (22%) styles, a consequence of the additional time spent in contact with the ground. The ground contact time, time to peak force, and time from peak force to toe-off (vertical and horizontal) were significantly longer for the parallel start. These temporal variables were also better correlated with sprint performance than any kinetic measure (0.42 ≤ r ≤ 0.75). The false start appears to be advantageous over short distances by improving push-off and the temporal characteristics of the first step.

  13. Regression models of sprint, vertical jump, and change of direction performance.

    PubMed

    Swinton, Paul A; Lloyd, Ray; Keogh, Justin W L; Agouris, Ioannis; Stewart, Arthur D

    2014-07-01

    It was the aim of the present study to expand on previous correlation analyses that have attempted to identify factors that influence performance of jumping, sprinting, and changing direction. This was achieved by using a regression approach to obtain linear models that combined anthropometric, strength, and other biomechanical variables. Thirty rugby union players participated in the study (age: 24.2 ± 3.9 years; stature: 181.2 ± 6.6 cm; mass: 94.2 ± 11.1 kg). The athletes' ability to sprint, jump, and change direction was assessed using a 30-m sprint, vertical jump, and 505 agility test, respectively. Regression variables were collected during maximum strength tests (1 repetition maximum [1RM] deadlift and squat) and performance of fast velocity resistance exercises (deadlift and jump squat) using submaximum loads (10-70% 1RM). Force, velocity, power, and rate of force development (RFD) values were measured during fast velocity exercises with the greatest values produced across loads selected for further analysis. Anthropometric data, including lengths, widths, and girths were collected using a 3-dimensional body scanner. Potential regression variables were first identified using correlation analyses. Suitable variables were then regressed using a best subsets approach. Three factor models generally provided the most appropriate balance between explained variance and model complexity. Adjusted R values of 0.86, 0.82, and 0.67 were obtained for sprint, jump, and change of direction performance, respectively. Anthropometric measurements did not feature in any of the top models because of their strong association with body mass. For each performance measure, variance was best explained by relative maximum strength. Improvements in models were then obtained by including velocity and power values for jumping and sprinting performance, and by including RFD values for change of direction performance. PMID:24345969

  14. Pediatric elbow injuries in athletes.

    PubMed

    Makhni, Eric C; Jegede, Kola A; Ahmad, Christopher S

    2014-09-01

    Elbow injuries in pediatric and adolescent population represent a spectrum of pathology that can range from medial tension injuries to posterior shear injuries. Elbow injuries in this population continue to rise in parallel with the increase in youth participation in sports both throughout the calendar year and across multiple sports. Many of these injuries are noncontact and are attributed to overuse. Evaluation and management of youth and adolescent athletic elbow injuries requires knowledge of developmental anatomy, injury pathophysiology, and established treatment algorithms. Furthermore, risk factors contributing to elbow injuries must be recognized, with education and recommendations for safe play continually advocated. This education--of parents, athletes, and coaches--is paramount in reducing the climbing incidence of elbow injuries in our youth athletes.

  15. Nutrient Needs of Young Athletes.

    ERIC Educational Resources Information Center

    Willenberg, Barbara; Hemmelgarn, Melinda

    1991-01-01

    Explains the nutritional requirements of children and adolescents, and the physiological roles of the major nutrients. Details the nutrient needs of young athletes, including pre- and postgame meals and fluid replacement. Discusses eating disorders and obesity. Advocates a diet rich in complex carbohydrates. (BC)

  16. Kinematic Determinants of Early Acceleration in Field Sport Athletes

    PubMed Central

    Murphy, Aron J.; Lockie, Robert G.; Coutts, Aaron J.

    2003-01-01

    Acceleration performance is important for field sport athletes that require a high level of repeat sprint ability. Although acceleration is widely trained for, there is little evidence outlining which kinematic factors delineate between good and poor acceleration. The aim of this study was to investigate the kinematic differences between individuals with fast and slow acceleration. Twenty field sport athletes were tested for sprint ability over the first three steps of a 15m sprint. Subjects were filmed at high speed to determine a range of lower body kinematic measures. For data analysis, subjects were then divided into relatively fast (n = 10) and slow (n = 10) groups based on their horizontal velocity. Groups were then compared across kinematic measures, including stride length and frequency, to determine whether they accounted for observed differences in sprint velocity. The results showed the fast group had significantly lower (~11-13%) left and right foot contact times (p < .05), and an increased stride frequency (~9%), as compared to the slow group. Knee extension was also significantly different between groups (p < .05). There was no difference found in stride length. It was concluded that those subjects who are relatively fast in early acceleration achieve this through reduced ground contact times resulting in an improved stride frequency. Training for improved acceleration should be directed towards using coaching instructions and drills that specifically train such movement adaptations. PMID:24688275

  17. The Female Athlete Triad.

    PubMed

    Weiss Kelly, Amanda K; Hecht, Suzanne

    2016-08-01

    The number of girls participating in sports has increased significantly since the introduction of Title XI in 1972. As a result, more girls have been able to experience the social, educational, and health-related benefits of sports participation. However, there are risks associated with sports participation, including the female athlete triad. The triad was originally recognized as the interrelationship of amenorrhea, osteoporosis, and disordered eating, but our understanding has evolved to recognize that each of the components of the triad exists on a spectrum from optimal health to disease. The triad occurs when energy intake does not adequately compensate for exercise-related energy expenditure, leading to adverse effects on reproductive, bone, and cardiovascular health. Athletes can present with a single component or any combination of the components. The triad can have a more significant effect on the health of adolescent athletes than on adults because adolescence is a critical time for bone mass accumulation. This report outlines the current state of knowledge on the epidemiology, diagnosis, and treatment of the triad conditions. PMID:27432852

  18. The young female athlete.

    PubMed

    Hurvitz, Michal; Weiss, Ram

    2009-12-01

    Participation of adolescents and young women in strenuous sports activity may lead to various metabolic and psychological derangements of clinical relevance to the endocrinologist. The most common manifestations encountered in practice are primary and secondary amenorrhea, reduced bone mineral density and eating disorders. The occurrence of all three together has been named "the athletic triad". The underlying hormonal drivers that lead to some of these manifestations are the reduced leptin level as well as the persistent low grade stress response commonly observed in such females. "Exercise-related female reproductive dysfunction" (ERFRD), can possibly include short-term (infertility) and long-term (osteoporosis) consequences. Functional hypothalamic amenorrhea, a manifestation of ERFRD in adolescence, is an integrated response to the combination of excessive physical and emotional stress, exercise, and/or reduced food intake characterized by decreased endogenous GNRH secretion. The primary aim of treating these athletes should be the prevention of the development of any component of the triad as well as the whole complex by educating athletes, trainers, parents and health care professionals about proper nutrition and safe training. The long term prognosis is good. However, significant long term morbidity may affect these young women later in life. PMID:20118893

  19. Hang cleans and hang snatches produce similar improvements in female collegiate athletes.

    PubMed

    Ayers, J L; DeBeliso, M; Sevene, T G; Adams, K J

    2016-09-01

    Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed.

  20. Hang cleans and hang snatches produce similar improvements in female collegiate athletes

    PubMed Central

    Ayers, JL; DeBeliso, M; Sevene, TG

    2016-01-01

    Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed. PMID:27601779

  1. Hang cleans and hang snatches produce similar improvements in female collegiate athletes.

    PubMed

    Ayers, J L; DeBeliso, M; Sevene, T G; Adams, K J

    2016-09-01

    Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed. PMID:27601779

  2. Hang cleans and hang snatches produce similar improvements in female collegiate athletes

    PubMed Central

    Ayers, JL; DeBeliso, M; Sevene, TG

    2016-01-01

    Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed.

  3. A novel compression garment with adhesive silicone stripes improves repeated sprint performance – a multi-experimental approach on the underlying mechanisms

    PubMed Central

    2014-01-01

    Background Repeated sprint performance is determined by explosive production of power, as well as rapid recovery between successive sprints, and there is evidence that compression garments and sports taping can improve both of these factors. Methods In each of two sub-studies, female athletes performed two sets of 30 30-m sprints (one sprint per minute), one set wearing compression garment with adhesive silicone stripes (CGSS) intended to mimic taping and the other with normal clothing, in randomized order. Sub-study 1 (n = 12) focused on cardio-respiratory, metabolic, hemodynamic and perceptual responses, while neuronal and biomechanical parameters were examined in sub-study 2 (n = 12). Results In both sub-studies the CGSS improved repeated sprint performance during the final 10 sprints (best P < 0.01, d = 0.61). None of the cardio-respiratory or metabolic variables monitored were altered by wearing this garment (best P = 0.06, d = 0.71). Also during the final 10 sprints, rating of perceived exertion by the upper leg muscles was reduced (P = 0.01, d = 1.1), step length increased (P = 0.01, d = 0.91) and activation of the m. rectus femoris elevated (P = 0.01, d = 1.24), while the hip flexion angle was lowered throughout the protocol (best P < 0.01, d = 2.28) and step frequency (best P = 0.34, d = 0.2) remained unaltered. Conclusion Although the physiological parameters monitored were unchanged, the CGSS appears to improve performance during 30 30-m repeated sprints by reducing perceived exertion and altering running technique. PMID:24914412

  4. Mechanical loading with or without weight-bearing activity: influence on bone strength index in elite female adolescent athletes engaged in water polo, gymnastics, and track-and-field.

    PubMed

    Greene, David A; Naughton, Geraldine A; Bradshaw, Elizabeth; Moresi, Mark; Ducher, Gaele

    2012-09-01

    Bone health is considered not to benefit from water-based sports because of their weight-supported nature, but available evidence primarily relies on DXA technology. Our purpose was to investigate musculoskeletal health in the upper and lower body in well-trained adolescent female athletes using pQCT and compare these athletes with less-active, age- and sex-matched peers. Bone mineral content, volumetric cortical and trabecular BMD, total and cortical area, and bone strength index were assessed at the distal and proximal tibia and radius in four groups of adolescent females (mean age, 14.9 years) including water polo players (n = 30), gymnasts (n = 25), track-and-field athletes (n = 34), and nonactive controls (n = 28). Water polo players did not show any benefit in bone strength index or muscle size in the lower leg when compared with controls. In contrast, gymnasts showed 60.1 % and 53.4 % greater bone strength index at the distal and proximal tibia, respectively, than nonactive females (p < 0.05). Similarly, track-and-field athletes displayed 33.9 % and 14.7 % greater bone strength index at the distal and proximal tibia, respectively, compared with controls (p < 0.05). In the upper body, water polo players had 31.9 % greater bone strength index at the distal radius, but not the radial shaft, and 15.2 % larger forearm muscle cross-sectional area than controls (p < 0.05). The greatest musculoskeletal benefits in the upper body were found in gymnasts. In conclusion, despite training at an elite level, female water polo players did not show any benefits in musculoskeletal health in the lower leg and only limited benefits in the upper body when compared with nonactive girls. PMID:22614913

  5. Mechanical loading with or without weight-bearing activity: influence on bone strength index in elite female adolescent athletes engaged in water polo, gymnastics, and track-and-field.

    PubMed

    Greene, David A; Naughton, Geraldine A; Bradshaw, Elizabeth; Moresi, Mark; Ducher, Gaele

    2012-09-01

    Bone health is considered not to benefit from water-based sports because of their weight-supported nature, but available evidence primarily relies on DXA technology. Our purpose was to investigate musculoskeletal health in the upper and lower body in well-trained adolescent female athletes using pQCT and compare these athletes with less-active, age- and sex-matched peers. Bone mineral content, volumetric cortical and trabecular BMD, total and cortical area, and bone strength index were assessed at the distal and proximal tibia and radius in four groups of adolescent females (mean age, 14.9 years) including water polo players (n = 30), gymnasts (n = 25), track-and-field athletes (n = 34), and nonactive controls (n = 28). Water polo players did not show any benefit in bone strength index or muscle size in the lower leg when compared with controls. In contrast, gymnasts showed 60.1 % and 53.4 % greater bone strength index at the distal and proximal tibia, respectively, than nonactive females (p < 0.05). Similarly, track-and-field athletes displayed 33.9 % and 14.7 % greater bone strength index at the distal and proximal tibia, respectively, compared with controls (p < 0.05). In the upper body, water polo players had 31.9 % greater bone strength index at the distal radius, but not the radial shaft, and 15.2 % larger forearm muscle cross-sectional area than controls (p < 0.05). The greatest musculoskeletal benefits in the upper body were found in gymnasts. In conclusion, despite training at an elite level, female water polo players did not show any benefits in musculoskeletal health in the lower leg and only limited benefits in the upper body when compared with nonactive girls.

  6. Heat acclimation improves intermittent sprinting in the heat but additional pre-cooling offers no further ergogenic effect.

    PubMed

    Castle, Paul; Mackenzie, Richard W; Maxwell, Neil; Webborn, Anthony D J; Watt, Peter W

    2011-08-01

    The aim of this study was to determine the effect of 10 days of heat acclimation with and without pre-cooling on intermittent sprint exercise performance in the heat. Eight males completed three intermittent cycling sprint protocols before and after 10 days of heat acclimation. Before acclimation, one sprint protocol was conducted in control conditions (21.8 ± 2.2°C, 42.8 ± 6.7% relative humidity) and two sprint protocols in hot, humid conditions (33.3 ± 0.6°C, 52.2 ± 6.8% relative humidity) in a randomized order. One hot, humid condition was preceded by 20 min of thigh pre-cooling with ice packs (-16.2 ± 4.5°C). After heat acclimation, the two hot, humid sprint protocols were repeated. Before heat acclimation, peak power output declined in the heat (P < 0.05) but pre-cooling prevented this. Ten days of heat acclimation reduced resting rectal temperature from 37.8 ± 0.3°C to 37.4 ± 0.3°C (P < 0.01). When acclimated, peak power output increased by ∼2% (P < 0.05, main effect) and no reductions in individual sprint peak power output were observed. Additional pre-cooling offered no further ergogenic effect. Unacclimated athletes competing in the heat should pre-cool to prevent reductions in peak power output, but heat acclimate for an increased peak power output. PMID:21777052

  7. Advancing hypoxic training in team sports: from intermittent hypoxic training to repeated sprint training in hypoxia.

    PubMed

    Faiss, Raphaël; Girard, Olivier; Millet, Grégoire P

    2013-12-01

    Over the past two decades, intermittent hypoxic training (IHT), that is, a method where athletes live at or near sea level but train under hypoxic conditions, has gained unprecedented popularity. By adding the stress of hypoxia during 'aerobic' or 'anaerobic' interval training, it is believed that IHT would potentiate greater performance improvements compared to similar training at sea level. A thorough analysis of studies including IHT, however, leads to strikingly poor benefits for sea-level performance improvement, compared to the same training method performed in normoxia. Despite the positive molecular adaptations observed after various IHT modalities, the characteristics of optimal training stimulus in hypoxia are still unclear and their functional translation in terms of whole-body performance enhancement is minimal. To overcome some of the inherent limitations of IHT (lower training stimulus due to hypoxia), recent studies have successfully investigated a new training method based on the repetition of short (<30 s) 'all-out' sprints with incomplete recoveries in hypoxia, the so-called repeated sprint training in hypoxia (RSH). The aims of the present review are therefore threefold: first, to summarise the main mechanisms for interval training and repeated sprint training in normoxia. Second, to critically analyse the results of the studies involving high-intensity exercises performed in hypoxia for sea-level performance enhancement by differentiating IHT and RSH. Third, to discuss the potential mechanisms underpinning the effectiveness of those methods, and their inherent limitations, along with the new research avenues surrounding this topic.

  8. Correlation between backpack weight and way of carrying, sagittal and frontal spinal curvatures, athletic activity, and dorsal and low back pain in schoolchildren and adolescents.

    PubMed

    Korovessis, Panagiotis; Koureas, Georgios; Papazisis, Zisis

    2004-02-01

    This cross-sectional study was carried out to investigate any correlation between backpack carrying, spinal curvatures, and athletic activities on schoolchildren's dorsal (DP) and low back pain (LBP). Three thousand four hundred forty-one students aged from 9 to 15 years who carried backpacks to school were included in this study and asked for DP and LBP experiences in the school period while carrying the backpack. Nonradiating methods (surface back contour analysis) were used to indirectly measure frontal spinal curve (scoliosis) with the scoliometer and lateral curves (thoracic kyphosis and lumbar lordosis) with the kyphometer. All data analyses were undertaken regarding school year level, age, gender, sports participation, backpack weight, and way of carrying (one versus both shoulder) in relation to magnitude of scoliosis, thoracic kyphosis, lumbar lordosis, and DP and LBP while carrying the backpack. DP increased with increasing backpack weight (P < 0.05). The way (one versus both shoulder) of backpack carrying did not correlate either with DP or with LBP. Girls experienced much more LBP and DP than boys (P < 0.001). There was no difference in the prevalence of LBP and DP between adolescents and children. Students' age, height, and body weight as well as magnitude of kyphosis, lordosis, and scoliosis did not correlate with either LBP or DP. At the age of 11 years, girls and boys showed the highest prevalence for DP (72% and 38.5%, respectively), while at the age of 14 years, girls reported significantly (P < 0.05) more DP than boys. Girls showed the highest prevalence of LBP (71%) at the age of 11 years, while for the boys, it was at the age of 15 years (21%). Girls showed at the age of 11 years significantly more LBP (P < 0.05) than boys. Sports exposure seemed to increase LBP in girls (P < 0.001). The results of this study suggest a differential DP and LBP prevalence in schoolchildren and adolescents carrying backpacks with regard to gender and age. The peak

  9. Indirect ultrasound measurement of humeral torsion in adolescent baseball players and non-athletic adults: reliability and significance.

    PubMed

    Whiteley, Rod; Ginn, Karen; Nicholson, Leslie; Adams, Roger

    2006-08-01

    Accurate clinical interpretation of shoulder rotation range requires knowledge of the contribution of humeral torsion. This study compares the reliability of indirectly measuring humeral torsion using ultrasound visualisation with direct palpation and compares the degree of humeral torsion in a non-throwing adult population with a population of elite adolescent baseballers. The reliability of a novel method of indirectly measuring humeral torsion using palpation and ultrasound was established prior to using the ultrasound method to determine the amount of humeral torsion in both humeri of a group of 16 non-throwing subjects and 36 elite adolescent baseball players. Excellent inter-tester reliability was found for the ultrasound method of measuring humeral torsion in each arm (ICC 2,1: 0.98 and 0.94) but poor reliability for the direct palpation method (ICC 2,1: 0.51 and 0.49). Using the ultrasound method, side-to-side differences in humeral torsion ranged from 0 to 13 degrees for the non-throwing group and 0 to 29 degrees for the baseball players. This side-to-side difference was significant in the baseball players (p<0.001) but not significant in the non-throwing group (p=0.43). Whilst side-to-side differences in humeral torsion were noted between all subjects irrespective of arm dominance, only throwers demonstrated consistently greater humeral retrotorsion in their throwing arm. A reliable clinical tool for estimating humeral torsion, such as that employed in this study, will allow for a more valid prescription of interventions for the treatment of shoulder dysfunction.

  10. Athlete's foot

    MedlinePlus

    Tinea pedis; Fungal infection - feet; Tinea of the foot; Infection - fungal - feet; Ringworm - foot ... Athlete's foot is the most common type of tinea infection. The fungus or yeast thrives in warm, ...

  11. Isoinertial and isokinetic sprints: muscle signalling.

    PubMed

    Fuentes, T; Ponce-González, J G; Morales-Alamo, D; de Torres-Peralta, R; Santana, A; De Pablos-Velasco, P; Olmedillas, H; Guadalupe-Grau, A; Rodríguez-García, L; Serrano-Sanchez, J A; Guerra, B; Calbet, J A L

    2013-04-01

    To determine if the muscle signalling response to a 30 s all-out sprint exercise is modulated by the exercise mode and the endocrine response, 27 healthy volunteers were divided in 2 groups that performed isokinetic (10 men and 5 women) and isoinertial (7 men and 5 women) Wingate tests. Blood samples and vastus lateralis muscle biopsies were taken before, immediately after, 30 and 120 min after the sprints. Groups were comparable in age, height, body weight, percentage of body fat, peak power per kg of lower extremities lean mass (Pmax) and muscle fibre types. However, the isoinertial group achieved a 25% greater mean power (Pmean). Sprint exercise elicited marked increases in the musculus vastus lateralis AMPKα, ACCβ, STAT3, STAT5 and ERK1/2 phosphorylation (all P<0.05). The AMPKα, STAT3, and ERK1/2 phosphorylation responses were more marked after the isoinertial than isokinetic test (interaction: P<0.01). The differences in muscle signalling could not be accounted for by differences in Pmax, although Pmean could explain part of the difference in AMPKα phosphorylation. The leptin, insulin, glucose, GH, IL-6, and lactate response were similar in both groups. In conclusion, the muscle signalling response to sprint exercise differs between isoinertial and isokinetic sprints.

  12. The short-term effect of whole-body vibration training on vertical jump, sprint, and agility performance.

    PubMed

    Cochrane, Darryl J; Legg, Stephen J; Hooker, Michael J

    2004-11-01

    Previous studies have suggested that short-term whole-body vibration (WBV) training produces neuromuscular improvement similar to that of power and strength training. However, it is yet to be determined whether short-term WBV exposure produces neurogenic enhancement for power, speed, and agility. The purpose of this study was to investigate the effect short-term WBV training had on vertical jump, sprint, and agility performance in nonelite athletes. Twenty-four sport science students (16 men and 8 women) were randomly assigned to 2 groups: WBV training or control. Each group included 8 men and 4 women. Countermovement jump (CMJ) height, squat jump (SJ) height, sprint speed over 5, 10, and 20 m, and agility (505, up and back) were performed by each participant before and after 9 days of either no training (control) or WBV training. Perceived discomfort of every participant was recorded after daily WBV exposure and nonexposure. There were no significant differences between WBV and control groups for CMJ, SJ, sprints, and agility. Perceived discomfort differed between the first and subsequent days of WBV training (p < 0.05); however, there was no difference between the WBV and control groups. It is concluded that short-term WBV training did not enhance performance in nonelite athletes.

  13. Effects of Strength Training on Squat and Sprint Performance in Soccer Players.

    PubMed

    Styles, William J; Matthews, Martyn J; Comfort, Paul

    2016-06-01

    Styles, WJ, Matthews, MJ, and Comfort, P. Effects of strength training on squat and sprint performance in soccer players. J Strength Cond Res 30(6): 1534-1539, 2016-Researchers have demonstrated that increases in strength result in increases in athletic performance, although the development of strength is still neglected in some sports. Our aim was to determine whether a simple in-season strength training program would result in increases in maximal squat strength and short sprint performance, in professional soccer players. Professional soccer players (n = 17, age = 18.3 ± 1.2 years, height = 1.79 ± 0.06 m, body mass [BM] = 75.5 ± 6.1 kg) completed 1 repetition maximum (1RM) back squat and sprint tests (5, 10, and 20 m) before and after a 6-week (×2 week) in-season strength training (85-90% 1RM) intervention. Strength training resulted in significant improvements in absolute and relative strength (before = 125.4 ± 13.8 kg, after = 149.3 ± 16.2 kg, p ≤ 0.001, Cohen's d = 0.62; 1RM/BM before: 1.66 ± 0.24 kg·kg, after = 1.96 ± 0.29 kg·kg, p ≤ 0.001, Cohen's d = 0.45; respectively). Similarly, there were small yet significant improvements in sprint performance over 5 m (before = 1.11 ± 0.04 seconds, after = 1.05 ± 0.05 seconds, p ≤ 0.001, Cohen's d = 0.55), 10 m (before = 1.83 ± 0.05 seconds, after = 1.78 ± 0.05 seconds, p ≤ 0.001, Cohen's d = 0.45), and 20 m (before = 3.09 ± 0.07 seconds, after = 3.05 ± 0.05 seconds, p ≤ 0.001, Cohen's d = 0.31). Changes in maximal squat strength seem to be reflected in improvements in short sprint performance highlighting the importance of developing maximal strength to improve short sprint performance. Moreover, this demonstrates that these improvements can be achieved during the competitive season in professional soccer players.

  14. Influence of a caffeine mouth rinse on sprint cycling following glycogen depletion.

    PubMed

    Kizzi, Joseph; Sum, Alvin; Houston, Fraser E; Hayes, Lawrence D

    2016-11-01

    Attenuated performance during intense exercise with limited endogenous carbohydrate (CHO) is well documented. Therefore, this study examined whether caffeine (CAF) mouth rinsing would augment performance during repeated sprint cycling in participants with reduced endogenous CHO. Eight recreationally active males (aged 23 ± 2 yr, body mass 84 ± 4 kg, stature 178 ± 7 cm) participated in this randomized, single-blind, repeated-measures crossover investigation. Following familiarization, participants attended two separate evening glycogen depletion sessions. The following morning, participants completed five, 6 s sprints on a cycle ergometer (separated by 24 s active recovery), with mouth rinsing either (1) a placebo solution or (2) a 2% CAF solution. During a fifth visit, participants completed the sprints without prior glycogen depletion. Repeated-measures ANOVA identified significant main effect of condition (CAF, placebo, and control [P < .05; effect size (ES) = 0.850-0.897]), sprint (1-5 [P < .005; ES = 0.871-0.986]), and interaction (condition × sprint [P < .05; ES = 0.831-0.846]), for peak and mean power. The control condition exhibited the highest peak power (overall mean 760 ± 77 W) and mean power (overall mean 699 ± 83W) over the five sprints (P < .001 in both instances). CAF peak power (overall mean 643 ± 79 W) was significantly greater than placebo (mean 573 ± 79 W [P < .05; ES = 0.850]). Additionally, CAF mean power (overall mean 589 ± 80 W) was significantly greater than placebo (519 ± 82 W [P < .05; ES = 0.397]). These data indicate that mouth rinsing a caffeinated solution reduces decrements caused by CHO reduction, which may benefit athletes wishing to train in a low-CHO state. PMID:27686403

  15. Effects of resisted sprint training on acceleration with three different loads accounting for 5, 12.5, and 20% of body mass.

    PubMed

    Bachero-Mena, Beatriz; González-Badillo, Juan José

    2014-10-01

    The optimal resisted load for sprint training has not been established yet, although it has been suggested that a resistance reducing the athlete's velocity by more than 10% from unloaded sprinting would entail substantial changes in the athlete's sprinting mechanics. This investigation has evaluated the effects of a 7-week, 14-session, sled-resisted sprint training on acceleration with 3 different loads according to a % of body mass (BM): low load (LL: 5% BM, n = 7), medium load (ML: 12.5% BM, n = 6), and high load (HL: 20% BM, n = 6), in young male students. Besides, the effects on untrained exercises: countermovement jump (CMJ), loaded vertical jump squat (JS), and full squat (SQ) were analyzed. The 3 groups followed the same training program consisting in maximal effort sprint accelerations with the respective loads assigned. Significant differences between groups only occurred between LL and ML in CMJ (p ≤ 0.05), favoring ML. Paired t-tests demonstrated statistical improvements in 0-40 m sprint times for the 3 groups (p ≤ 0.05), and in 0-20 m (p ≤ 0.05) and 0-30 m (p < 0.01) sprint times for HL. Sprint times in 10-40 m (p < 0.01) and 20-40 m (p ≤ 0.05) were improved in LL. Time intervals in 20-30 m and 20-40 m (p ≤ 0.05) were statistically reduced in ML. As regards, the untrained exercises, CMJ and SQ for ML and HL (p ≤ 0.05) and JS for HL were improved. The results show that depending on the magnitude of load used, the related effects will be attained in different phases of the 40 m. It would seem that to improve the initial phase of acceleration up to 30 m, loads around 20% of BM should be used, whereas to improve high-speed acceleration phases, loads around 5-12.5% of BM should be preferred. Moreover, sprint-resisted training with ML and HL would enhance vertical jump and leg strength in moderately trained subjects.

  16. How Joint Torques Affect Hamstring Injury Risk in Sprinting Swing–Stance Transition

    PubMed Central

    SUN, YULIANG; WEI, SHUTAO; ZHONG, YUNJIAN; FU, WEIJIE; LI, LI; LIU, YU

    2015-01-01

    ABSTRACT Purpose The potential mechanisms of hamstring strain injuries in athletes are not well understood. The study, therefore, was aimed at understanding hamstring mechanics by studying loading conditions during maximum-effort overground sprinting. Methods Three-dimensional kinematics and ground reaction force data were collected from eight elite male sprinters sprinting at their maximum effort. Maximal isometric torques of the hip and knee were also collected. Data from the sprinting gait cycle were analyzed via an intersegmental dynamics approach, and the different joint torque components were calculated. Results During the initial stance phase, the ground reaction force passed anteriorly to the knee and hip, producing an extension torque at the knee and a flexion torque at the hip joint. Thus, the active muscle torque functioned to produce flexion torque at the knee and extension torque at the hip. The maximal muscle torque at the knee joint was 1.4 times the maximal isometric knee flexion torque. During the late swing phase, the muscle torque counterbalanced the motion-dependent torque and acted to flex the knee joint and extend the hip joint. The loading conditions on the hamstring muscles were similar to those of the initial stance phase. Conclusions During both the initial stance and late swing phases, the large passive torques at both the knee and hip joints acted to lengthen the hamstring muscles. The active muscle torques generated mainly by the hamstrings functioned to counteract those passive effects. As a result, during sprinting or high-speed locomotion, the hamstring muscles may be more susceptible to high risk of strain injury during these two phases. PMID:24911288

  17. The sports performance application of vibration exercise for warm-up, flexibility and sprint speed.

    PubMed

    Cochrane, Darryl

    2013-01-01

    Since the turn of the 21st century, there has been a resurgence of vibration technology to enhance sport science especially for power and force development. However, vibration exercise has been trialled in other areas that are central to athlete performance such as warm-up, flexibility and sprint speed. Therefore, the aim of this review was to attempt to gain a better understanding of how acute and short-term vibration exercise may impact on warm-up, flexibility and sprint speed. The importance of warming up for sporting performance has been well documented and vibration exercise has the capability to be included or used as a standalone warm-up modality to increase intramuscular temperature at a faster rate compared to other conventional warm-up modalities. However, vibration exercise does not provide any additional neurogenic benefits compared to conventional dynamic and passive warm-up interventions. Vibration exercise appears to be a safe modality that does not produce any adverse affects causing injury or harm and could be used during interval and substitution breaks, as it would incur a low metabolic cost and be time-efficient compared to conventional warm-up modalities. Acute or short-term vibration exercise can enhance flexibility and range of motion without having a detrimental effect on muscle power, however it is less clear which mechanisms may be responsible for this enhancement. It appears that vibration exercise is not capable of improving sprint speed performance; this could be due to the complex and dynamic nature of sprinting where the purported increase in muscle power from vibration exercise is probably lost on repeated actions of high force generation. Vibration exercise is a safe modality that produces no adverse side effects for injury or harm. It has the time-efficient capability of providing coaches, trainers, and exercise specialists with an alternative modality that can be implemented for warm-up and flexibility either in isolation or in

  18. Enhancing team-sport athlete performance: is altitude training relevant?

    PubMed

    Billaut, François; Gore, Christopher J; Aughey, Robert J

    2012-09-01

    Field-based team sport matches are composed of short, high-intensity efforts, interspersed with intervals of rest or submaximal exercise, repeated over a period of 60-120 minutes. Matches may also be played at moderate altitude where the lower oxygen partial pressure exerts a detrimental effect on performance. To enhance run-based performance, team-sport athletes use varied training strategies focusing on different aspects of team-sport physiology, including aerobic, sprint, repeated-sprint and resistance training. Interestingly, 'altitude' training (i.e. living and/or training in O(2)-reduced environments) has only been empirically employed by athletes and coaches to improve the basic characteristics of speed and endurance necessary to excel in team sports. Hypoxia, as an additional stimulus to training, is typically used by endurance athletes to enhance performance at sea level and to prepare for competition at altitude. Several approaches have evolved in the last few decades, which are known to enhance aerobic power and, thus, endurance performance. Altitude training can also promote an increased anaerobic fitness, and may enhance sprint capacity. Therefore, altitude training may confer potentially-beneficial adaptations to team-sport athletes, which have been overlooked in contemporary sport physiology research. Here, we review the current knowledge on the established benefits of altitude training on physiological systems relevant to team-sport performance, and conclude that current evidence supports implementation of altitude training modalities to enhance match physical performances at both sea level and altitude. We hope that this will guide the practice of many athletes and stimulate future research to better refine training programmes.

  19. Reliability of a Cycle Ergometer Peak Power Test in Running-based Team Sport Athletes: A Technical Report.

    PubMed

    Wehbe, George M; Gabbett, Tim J; Hartwig, Timothy B; Mclellan, Christopher P

    2015-07-01

    Given the importance of ensuring athletes train and compete in a nonfatigued state, reliable tests are required to regularly monitor fatigue. The purpose of this study was to investigate the reliability of a cycle ergometer to measure peak power during short maximal sprint cycle efforts in running-based team sport athletes. Fourteen professional male Australian rules footballers performed a sprint cycle protocol during 3 separate trials, with each trial separated by 7 days. The protocol consisted of a standardized warm-up, a maximal 6-second sprint cycle effort, a 1-minute active recovery, and a second maximal 6-second sprint cycle effort. Peak power was recorded as the highest power output of the 2 sprint cycle efforts. Absolute peak power (mean ± SD) was 1502 ± 202, 1498 ± 191, and 1495 ± 210 W for trials 1, 2, and 3, respectively. The mean coefficient of variation, intraclass correlation coefficient, and SE of measurement for peak power between trials was 3.0% (90% confidence intervals [CIs] = 2.5-3.8%), 0.96 (90% CIs = 0.91-0.98), and 39 W, respectively. The smallest worthwhile change for relative peak power was 6.0%, which equated to 1.03 W·kg⁻¹. The cycle ergometer sprint test protocol described in this study is highly reliable in elite Australian rules footballers and can be used to track meaningful changes in performance over time, making it a potentially useful fatigue-monitoring tool.

  20. The acute effects of static stretching on the sprint performance of collegiate men in the 60- and 100-m dash after a dynamic warm-up.

    PubMed

    Kistler, Brandon M; Walsh, Mark S; Horn, Thelma S; Cox, Ronald H

    2010-09-01

    Previous research has shown that static stretching has an inhibitory effect on sprinting performances up to 50 m. The purpose of this study was to see what would happen to these effects at longer distances such as those seen in competition. This study used a within-subjects design to investigate the effects of passive static stretching vs. no stretching on the 60- and 100-m sprint performance of college track athletes after a dynamic warm-up. Eighteen male subjects completed both the static stretching and the no stretching conditions in counterbalanced order across 2 days of testing. On each day, all subjects first completed a generalized dynamic warm-up routine that included a self-paced 800-m run, followed by a series of dynamic movements, sprint, and hurdle drills. At the end of this generalized warm-up, athletes were assigned to either a static stretching or a no-stretching condition. They then immediately performed 2 100-m trials with timing gates set up at 20, 40, 60, and 100 m. Results revealed a significant slowing in performance with static stretching (p < 0.039) in the second 20 (20-40) m of the sprint trials. After the first 40 m, static stretching exhibited no additional inhibition of performance in a 100-m sprint. However, although there was no additional time loss, athletes never gained back the time that was originally lost in the first portion of the trials. Therefore, in strict terms of performance, it seems harmful to include static stretching in the warm-up protocol of collegiate male sprinters in distances up to 100 m.

  1. Field monitoring of sprinting power-force-velocity profile before, during and after hamstring injury: two case reports.

    PubMed

    Mendiguchia, J; Edouard, P; Samozino, P; Brughelli, M; Cross, M; Ross, A; Gill, N; Morin, J B

    2016-01-01

    Very little is currently known about the effects of acute hamstring injury on over-ground sprinting mechanics. The aim of this research was to describe changes in power-force-velocity properties of sprinting in two injury case studies related to hamstring strain management: Case 1: during a repeated sprint task (10 sprints of 40 m) when an injury occurred (5th sprint) in a professional rugby player; and Case 2: prior to (8 days) and after (33 days) an acute hamstring injury in a professional soccer player. A sports radar system was used to measure instantaneous velocity-time data, from which individual mechanical profiles were derived using a recently validated method based on a macroscopic biomechanical model. Variables of interest included: maximum theoretical velocity (V0) and horizontal force (F(H0)), slope of the force-velocity (F-v) relationship, maximal power, and split times over 5 and 20 m. For Case 1, during the injury sprint (sprint 5), there was a clear change in the F-v profile with a 14% greater value of F(H0) (7.6-8.7 N/kg) and a 6% decrease in V0 (10.1 to 9.5 m/s). For Case 2, at return to sport, the F-v profile clearly changed with a 20.5% lower value of F(H0) (8.3 vs. 6.6 N/kg) and no change in V0. The results suggest that the capability to produce horizontal force at low speed (F(H0)) (i.e. first metres of the acceleration phase) is altered both before and after return to sport from a hamstring injury in these two elite athletes with little or no change of maximal velocity capabilities (V0), as evidenced in on-field conditions. Practitioners should consider regularly monitoring horizontal force production during sprint running both from a performance and injury prevention perspective. PMID:26648237

  2. Explosive force production during isometric squats correlates with athletic performance in rugby union players.

    PubMed

    Tillin, Neale Anthony; Pain, Matthew Thomas Gerard; Folland, Jonathan

    2013-01-01

    This study investigated the association between explosive force production during isometric squats and athletic performance (sprint time and countermovement jump height). Sprint time (5 and 20 m) and jump height were recorded in 18 male elite-standard varsity rugby union players. Participants also completed a series of maximal- and explosive-isometric squats to measure maximal force and explosive force at 50-ms intervals up to 250 ms from force onset. Sprint performance was related to early phase (≤100 ms) explosive force normalised to maximal force (5 m, r = -0.63, P = 0.005; and 20 m, r = -0.54, P = 0.020), but jump height was related to later phase (>100 ms) absolute explosive force (0.51 < r < 0.61; 0.006 < P < 0.035). When participants were separated for 5-m sprint time (< or ≥ 1s), the faster group had greater normalised explosive force in the first 150 ms of explosive-isometric squats (33-67%; 0.001 < P < 0.017). The results suggest that explosive force production during isometric squats was associated with athletic performance. Specifically, sprint performance was most strongly related to the proportion of maximal force achieved in the initial phase of explosive-isometric squats, whilst jump height was most strongly related to absolute force in the later phase of the explosive-isometric squats.

  3. [Anabolic steroids in athletes].

    PubMed

    Yesalis, C E; Wright, J E; Lombardo, J A

    1992-01-01

    The use of anabolic-androgenic steroids (AS) to enhance appearance as well as physical/physiological capacities has increased dramatically over the past four decades in all age groups from early adolescence to adulthood. Although higher AS use rates are reported by elite and competitive athletes, a significant number of recreational athletes appear to be using AS. The scientific literature is inconsistent and at times at odds with the conventional wisdom and empirical experiences of the athletic community regarding the ergogenic effects of AS. However, individuals experienced in weight training, with an adequate diet, and who continue training during AS administration seem to consistently increase their strength and lean mass over what would have been expected from training alone. Previous research documenting deleterious but transient and mostly asymptomatic acute changes in physiology, risk factors and behavior has been inconclusive regarding the long term health impact. The abuse of AS constitutes a special challenge to society. AS are not euphorigenic or mood altering immediately following administration, as are other illicit drugs; the appetite for AS has been created predominantly by our societal fixations on winning and physical appearance. Consequently any successful intervention in this area must go beyond education, law enforcement and drug testing, and attempt to change a social environment which currently encourages the use of AS.

  4. Athletic Activity and Hormone Concentrations in High School Female Athletes

    PubMed Central

    Wojtys, Edward M.; Jannausch, Mary L.; Kreinbrink, Jennifer L.; Harlow, Siobán D.; Sowers, MaryFran R.

    2015-01-01

    Context: Physical activity may affect the concentrations of circulating endogenous hormones in female athletes. Understanding the relationship between athletic and physical activity and circulating female hormone concentrations is critical. Objective: To test the hypotheses that (1) the estradiol-progesterone profile of high school adolescent girls participating in training, conditioning, and competition would differ from that of physically inactive, age-matched adolescent girls throughout a 3-month period; and (2) athletic training and conditioning would alter body composition (muscle, bone), leading to an increasingly greater lean–body-mass to fat–body-mass ratio with accompanying hormonal changes. Design: Cohort study. Settings: Laboratory and participants' homes. Patients or Other Participants: A total of 106 adolescent girls, ages 14–18 years, who had experienced at least 3 menstrual cycles in their lifetime. Main Outcome Measure(s): Participants were prospectively monitored throughout a 13-week period, with weekly physical activity assessments and 15 urine samples for estrogen, luteinizing hormone, creatinine, and progesterone concentrations. Each girl underwent body-composition measurements before and after the study period. Results: Seventy-four of the 98 girls (76%) who completed the study classified themselves as athletes. Body mass index, body mass, and fat measures remained stable, and 17 teenagers had no complete menstrual cycle during the observation period. Mean concentrations of log(estrogen/creatinine) were slightly greater in nonathletes who had cycles of <24 or >35 days. Mean log(progesterone/creatinine) concentrations in nonathletes were less in the first half and greater in the second half of the cycle, but the differences were not statistically significant. Conclusions: A moderate level of athletic or physical activity did not influence urine concentrations of estrogen, progesterone, or luteinizing hormones. However, none of the

  5. The effects of passive warm-up vs. whole-body vibration on high-intensity performance during sprint cycle exercise.

    PubMed

    Avelar, Núbia C P; Costa, Sidney J; da Fonseca, Sueli F; Tossige-Gomes, Rosalina; Gripp, Fernando J; Coimbra, Cândido C; Lacerda, Ana C R

    2012-11-01

    The purpose of this study was to compare the effects of passive warm-up (PW), whole-body vibration (WBV), and control (C) on high-intensity performance during sprint cycle exercise. Six recreationally trained men performed a 30-second sprint cycle test after the 3 aforementioned conditions; each test was carried out on a different day after balanced-order experimental tests. The WBV consisted of 5 minutes of squats associated with WBV (45 Hz, 2 mm). The PW consisted of 30 minutes of PW using a thermal blanket on the thighs and legs (35 W). The C consisted of 30 minutes of no warm-up with the subject lying down. Motor neuron excitability from the vastus lateralis muscle, evaluated by electromyography (EMG), was determined before exercise at rest and during sprint cycle exercise. Blood lactate levels (BLs), evaluated by spectroscopy, and muscle temperature (MT) of the thigh, estimated indirectly by measuring skin temperature, were determined at following time points: before exercise at rest (before and after experimental conditions), immediately, and 3 minutes after the 30-second sprint cycle test. Peak power, relative power, relative work, time of peak power, and pedaling cadence were significantly higher in the WBV compared with that for C (p < 0.05). Although MT was significantly greater in PW compared with that in WBV and C before exercise (p < 0.01), no significant differences were observed between the experimental conditions for BL immediately after sprint cycle exercise (p = 0.35) and in EMG during sprint cycle exercise (p = 0.16). Thus, it is plausible to suggest WBV as a method for an acute increase in high-intensity performance during sprint cycle exercise for athletes immediately before competition or training.

  6. Left ventricular morphology and function in female athletes: a meta-analysis.

    PubMed

    Whyte, G P; George, K; Nevill, A; Shave, R; Sharma, S; McKenna, W J

    2004-07-01

    The purpose of the present study was to examine the impact of physical training upon cardiac structure and function, and identify physiologic upper limits in female athletes. Meta-analytical techniques were applied to 13 published echocardiographic studies examining cardiac structure and function in female athletes. The study group included 890 athletes and 333 controls. For comparison of sporting discipline, studies were partitioned into 3 categories (endurance, strength/sprint, team). Significant (p < 0.05) effect sizes were observed for all structural measures between athletes and controls. Significant effect size differences existed between sporting groups for LVIDd and LVM only, with endurance and team game athletes demonstrating the largest effect sizes compared to strength trained athletes. No significant effect of training was observed for left ventricular diastolic or systolic function, with the exception of stroke volume where a significant effect size difference was observed between athletes and controls with no observed difference between sporting groups. Maximum reported upper limits for LV wall thickness and LVIDd in female athletes were 12 mm and 66 mm respectively. Chronic exercise training results in cardiac enlargement in female athletes. The nature of physiologic adaptation is similar to that observed in male athletes. LV wall thickness values greater than 12 mm in female athletes should be viewed with caution and indicate a more comprehensive evaluation to establish a physiological or pathological basis for the observed left ventricular enlargement.

  7. Athletics, Athletic Leadership, and Academic Achievement

    ERIC Educational Resources Information Center

    Yeung, Ryan

    2015-01-01

    This study examines the relationship between athletics, athletic leadership, and academic achievement. This is likely to be a tricky issue as athletes and athletic leaders are not likely to be a random group of students. To address this issue I control for school fixed effects and instrument the endogenous variables with height. I find that…

  8. Liability, Athletic Equipment, and the Athletic Trainer.

    ERIC Educational Resources Information Center

    Black, Richard

    Standards of conduct, roles, and responsibilities expected of athletic trainers should be developed and disseminated. These guidelines could be used in court to show that the athletic trainer was following basic standards if he should be charged with liability. A review of liability cases involving athletic injuries received while athletes were…

  9. Athletic footwear.

    PubMed

    Smith, L S; Bunch, R

    1986-10-01

    The development of technical athletic footwear is based on two interrelated principles: injury prevention and enhanced performance. Most athletes are interested in and will benefit from shoes that prevent injuries. On the other hand, in many situations, competitive or elite athletes might be willing to accept the increased injury risk if the shoe can enhance performance. For these performance athletes, injury prevention may be a less important consideration. Emphasis can be placed on ultra-lightweight shoes which maximize energy return and do not restrict the desirable motions of the individual sport. Every sport demands a specific shoe. The process of new shoe development is similar to those categories already described: an understanding of the sport's biomechanics; an evaluation of the sport's injury patterns; prototype construction; wear-testing to insure fit, comfort, and playability; and manufacturing. Sports with large numbers of participants get the most attention, but lesser known sports demand the same detailed development. Softball, field hockey, boxing, and wrestling are, to name a few, sports which require specialty footwear. As our understanding improves in each sport, footwear technology and construction will follow.

  10. The post-activation potentiation effect on sprint performance after combined resistance/sprint training in junior basketball players.

    PubMed

    Tsimachidis, Constantinos; Patikas, Dimitrios; Galazoulas, Christos; Bassa, Eleni; Kotzamanidis, Christos

    2013-01-01

    The aim of this study was to examine the effect of a 10-week combined resistance/sprint training programme in the post-activation potentiation of sprint performance before, between and after resistance training sets. Twenty-six junior basketball players were randomly divided into a control and a combined training group. The combined training group performed a combined training programme consisting of 5 sets at 5-8 RM (Repetition Maximum) half-squats with sprints performed between each set. Post-activation potentiation was considered as the increase in sprint velocity in trials executed between and after the resistance sets compared with the sprint trial performed before the resistance sets of the respective first and last training session. For sprint evaluation the running distances 0-10 and 0-30 m were selected. The intervention increased both strength and sprint performance. No post-activation potentiation effect was observed during the first training session in either group. Post-activation potentiation appeared in the combined training group during the last training session of the intervention in both 0-10 and 0-30 m sprint. This study illustrates that post-activation potentiation effect on sprint performance in junior basketball players, who did not previously follow systematic resistance training, emerges after a 10-week resistance/sprint combined training programme.

  11. Perceived parenting styles differ between genders but not between elite athletes and controls.

    PubMed

    Brand, Serge; Gerber, Markus; Beck, Johannes; Kalak, Nadeem; Hatzinger, Martin; Pühse, Uwe; Holsboer-Trachsler, Edith

    2011-01-01

    For adolescent elite athletes, parental financial and emotional support is crucial. However, parents of elite athletes may be critical and demanding. Moreover, there is evidence that girls report more favorable perceived parenting styles compared with boys. The aim of the present study was to investigate perceived parenting styles among female and male adolescent elite athletes and controls. We sampled 258 adolescent elite athletes (139 females, 119 males) and 176 controls (139 females, 37 males). Participants completed a questionnaire to assess perceived parenting styles (support, commendation, reproach, restriction, inconsistency). Results showed that parenting styles did not differ between athletes and controls, except for restriction, for which athletes reported lower levels. Female adolescents had higher scores for positive and lower scores for negative perceived parenting styles. PMID:24600271

  12. Perceived parenting styles differ between genders but not between elite athletes and controls

    PubMed Central

    Brand, Serge; Gerber, Markus; Beck, Johannes; Kalak, Nadeem; Hatzinger, Martin; Pühse, Uwe; Holsboer-Trachsler, Edith

    2011-01-01

    For adolescent elite athletes, parental financial and emotional support is crucial. However, parents of elite athletes may be critical and demanding. Moreover, there is evidence that girls report more favorable perceived parenting styles compared with boys. The aim of the present study was to investigate perceived parenting styles among female and male adolescent elite athletes and controls. We sampled 258 adolescent elite athletes (139 females, 119 males) and 176 controls (139 females, 37 males). Participants completed a questionnaire to assess perceived parenting styles (support, commendation, reproach, restriction, inconsistency). Results showed that parenting styles did not differ between athletes and controls, except for restriction, for which athletes reported lower levels. Female adolescents had higher scores for positive and lower scores for negative perceived parenting styles. PMID:24600271

  13. Analysis of sprinting activities of professional soccer players.

    PubMed

    Andrzejewski, Marcin; Chmura, Jan; Pluta, Beata; Strzelczyk, Ryszard; Kasprzak, Andrzej

    2013-08-01

    The aim of the study was a detailed analysis of the sprinting activity of professional soccer players. The study involved 147 players who played in 10 matches of the 2008-09 and 2010-11 UEFA Europa League seasons. The number of performed sprints and total sprint distances covered by the players were examined using collected statistical material. Two types of sprints were distinguished based on their duration: S, short-duration sprint (below 5 seconds) and L, long-duration sprint (above 5 seconds). Additionally, sprints were classified according to their distance: 0-10, 10.1-20.0, and >20 m, respectively. The analysis of the sprinting activity of soccer players also involved their respective positions of play. The study was carried out using Amisco Pro (version. 1.0.2), one of the most comprehensive up-to-date computer systems for match analysis. The statistical analysis revealed that the mean total sprint distance covered by players (≥24 km·h) amounted to 237 ± 123 m. With regard to the position of play, the forwards covered the longest sprint distance (345 ± 129 m), that is, 9% longer than midfielders (313 ± 119 m) and over 100% longer than central midfielders (167 ± 87 m). The average number of sprints performed by the soccer players was 11.2 ± 5.3. It should also be emphasized that about 90% of sprints performed by professional soccer players were shorter than 5 seconds, whereas only 10% were longer than 5 seconds. Analysis of physical loads of soccer players during matches can be useful for individualization of training of soccer players' speed capabilities. It is an essential instrument of modern planning and application of training loads.

  14. Effect of 8 days of a hypergravity condition on the sprinting speed and lower-body power of elite rugby players.

    PubMed

    Barr, Matthew J; Gabbett, Tim J; Newton, Robert U; Sheppard, Jeremy M

    2015-03-01

    -Sprinting speed and lower-body power are considered to be key physical abilities for rugby players. A method of improving the lower-body power of athletes is simulated hypergravity. This method involves wearing a weighted vest at all times during the day for an extended period of time. There are no studies that have examined the effect of hypergravity on speed or the benefit for rugby players. An experimental group (n = 8) and a control group (n = 7) of national team rugby players took part in the study, which consisted of rugby, conditioning, speed, and strength sessions. The experimental group wore a weighted vest equating to 12% of their body mass for 8 days. All players were tested for speed and lower-body power before, 2 days after, and 9 days after the intervention. Speed testing involved the athletes completing 40-m sprints with timing lights and high-speed video cameras assessing acceleration and maximal velocity sprinting kinematics. Lower-body power was assessed using weighted countermovement jumps (CMJs). No group differences were found for sprinting speed at any point. The experimental group displayed a large decrease in acceleration ground contact time (-0.01 ± 0.005 s, d = 1.07) and a moderate increase in 15-kg CMJ velocity (0.07 ± 0.11 m·s, d = 0.71). Individual responses showed that players in the experimental group had both negative and positive speed and power responses to the training intervention. Simulated hypergravity for 8 days is likely ineffective at improving sprinting speed while undergoing standard rugby training.

  15. The Anemias of Athletes.

    ERIC Educational Resources Information Center

    Eichner, Edward R.

    1986-01-01

    Diagnosing anemia in athletes is complicated because athletes normally have a pseudoanemia that needs no treatment. Athletes, however, can develop anemia from iron deficiency or footstrike hemolysis, which require diagnosis and treatment. (Author/MT)

  16. Kinematics of transition during human accelerated sprinting

    PubMed Central

    Nagahara, Ryu; Matsubayashi, Takeo; Matsuo, Akifumi; Zushi, Koji

    2014-01-01

    ABSTRACT This study investigated kinematics of human accelerated sprinting through 50 m and examined whether there is transition and changes in acceleration strategies during the entire acceleration phase. Twelve male sprinters performed a 60-m sprint, during which step-to-step kinematics were captured using 60 infrared cameras. To detect the transition during the acceleration phase, the mean height of the whole-body centre of gravity (CG) during the support phase was adopted as a measure. Detection methods found two transitions during the entire acceleration phase of maximal sprinting, and the acceleration phase could thus be divided into initial, middle, and final sections. Discriminable kinematic changes were found when the sprinters crossed the detected first transition—the foot contacting the ground in front of the CG, the knee-joint starting to flex during the support phase, terminating an increase in step frequency—and second transition—the termination of changes in body postures and the start of a slight decrease in the intensity of hip-joint movements, thus validating the employed methods. In each acceleration section, different contributions of lower-extremity segments to increase in the CG forward velocity—thigh and shank for the initial section, thigh, shank, and foot for the middle section, shank and foot for the final section—were verified, establishing different acceleration strategies during the entire acceleration phase. In conclusion, there are presumably two transitions during human maximal accelerated sprinting that divide the entire acceleration phase into three sections, and different acceleration strategies represented by the contributions of the segments for running speed are employed. PMID:24996923

  17. Fatigue during intermittent-sprint exercise.

    PubMed

    Bishop, David J

    2012-09-01

    1. There is a reversible decline in force production by muscles when they are contracting at or near their maximum capacity. The task-dependent nature of fatigue means that the mechanisms of fatigue may differ between different types of contractions. This paper examines how fatigue manifests during whole-body, intermittent-sprint exercise and discusses the potential muscular and neural mechanisms that underpin this fatigue. 2. Fatigue is defined as a reversible, exercise-induced reduction in maximal power output (e.g. during cycling exercise) or speed (e.g. during running exercise), even though the task can be continued. 3. The small changes in surface electromyogram (EMG), along with a lack of change in voluntary muscle activation (estimated from both percutaneous motor nerve stimulations and trans-cranial magnetic stimulation), indicate that there is little change in neural drive to the muscles following intermittent-sprint exercise. This, along with the observation that the decrease in EMG is much less than that which would be predicted from the decrease in power output, suggests that peripheral mechanisms are the predominant cause of fatigue during intermittent-sprint exercise. 4. At the muscle level, limitations in energy supply, including phosphocreatine hydrolysis and the degree of reliance on anaerobic glycolysis and oxidative metabolism, and the intramuscular accumulation of metabolic by-products, such as hydrogen ions, emerge as key factors responsible for fatigue.

  18. The effect of 40-m repeated sprint training on maximum sprinting speed, repeated sprint speed endurance, vertical jump, and aerobic capacity in young elite male soccer players.

    PubMed

    Tønnessen, Espen; Shalfawi, Shaher A I; Haugen, Thomas; Enoksen, Eystein

    2011-09-01

    The purpose of this study was to examine the effect of 10 weeks' 40-m repeated sprint training program that does not involve strength training on sprinting speed and repeated sprint speed on young elite soccer players. Twenty young well-trained elite male soccer players of age (±SD) 16.4 (±0.9) years, body mass 67.2 (±9.1) kg, and stature 176.3 (±7.4) cm volunteered to participate in this study. All participants were tested on 40-m running speed, 10 × 40-m repeated sprint speed, 20-m acceleration speed, 20-m top speed, countermovement jump (CMJ), and aerobic endurance (beep test). Participants were divided into training group (TG) (n = 10) and control group (CG) (n = 10). The study was conducted in the precompetition phase of the training program for the participants and ended 13 weeks before the start of the season; the duration of the precompetition period was 26 weeks. The TG followed a Periodized repeated sprint training program once a week. The training program consisted of running 40 m with different intensities and duration from week to week. Within-group results indicate that TG had a statistically marked improvement in their performance from pre to posttest in 40-m maximum sprint (-0.06 seconds), 10 × 40-m repeated sprint speed (-0.12 seconds), 20- to 40-m top speed (-0.05 seconds), and CMJ (2.7 cm). The CG showed only a statistically notable improvement from pre to posttest in 10 × 40-m repeated sprint speed (-0.06 seconds). Between-group differences showed a statistically marked improvement for the TG over the CG in 10 × 40-m repeated sprint speed (-0.07 seconds) and 20- to 40-m top speed (-0.05 seconds), but the effect of the improvement was moderate. The results further indicate that a weekly training with repeated sprint gave a moderate but not statistically marked improvement in 40-m sprinting, CMJ, and beep test. The results of this study indicate that the repeated sprint program had a positive effect on several of the parameters tested

  19. The effect of 40-m repeated sprint training on maximum sprinting speed, repeated sprint speed endurance, vertical jump, and aerobic capacity in young elite male soccer players.

    PubMed

    Tønnessen, Espen; Shalfawi, Shaher A I; Haugen, Thomas; Enoksen, Eystein

    2011-09-01

    The purpose of this study was to examine the effect of 10 weeks' 40-m repeated sprint training program that does not involve strength training on sprinting speed and repeated sprint speed on young elite soccer players. Twenty young well-trained elite male soccer players of age (±SD) 16.4 (±0.9) years, body mass 67.2 (±9.1) kg, and stature 176.3 (±7.4) cm volunteered to participate in this study. All participants were tested on 40-m running speed, 10 × 40-m repeated sprint speed, 20-m acceleration speed, 20-m top speed, countermovement jump (CMJ), and aerobic endurance (beep test). Participants were divided into training group (TG) (n = 10) and control group (CG) (n = 10). The study was conducted in the precompetition phase of the training program for the participants and ended 13 weeks before the start of the season; the duration of the precompetition period was 26 weeks. The TG followed a Periodized repeated sprint training program once a week. The training program consisted of running 40 m with different intensities and duration from week to week. Within-group results indicate that TG had a statistically marked improvement in their performance from pre to posttest in 40-m maximum sprint (-0.06 seconds), 10 × 40-m repeated sprint speed (-0.12 seconds), 20- to 40-m top speed (-0.05 seconds), and CMJ (2.7 cm). The CG showed only a statistically notable improvement from pre to posttest in 10 × 40-m repeated sprint speed (-0.06 seconds). Between-group differences showed a statistically marked improvement for the TG over the CG in 10 × 40-m repeated sprint speed (-0.07 seconds) and 20- to 40-m top speed (-0.05 seconds), but the effect of the improvement was moderate. The results further indicate that a weekly training with repeated sprint gave a moderate but not statistically marked improvement in 40-m sprinting, CMJ, and beep test. The results of this study indicate that the repeated sprint program had a positive effect on several of the parameters tested

  20. Longitudinal Study Evaluating Postural Balance of Young Athletes.

    PubMed

    Steinberg, Nili; Nemet, Dan; Pantanowitz, Michal; Zeev, Aviva; Hallumi, Monder; Sindiani, Mahmood; Meckel, Yoav; Eliakim, Alon

    2016-02-01

    Repeated anaerobic conditions during athletic performance may cause general and local fatigue that result in postural balance deficit. Evidence suggests that improved postural balance during athletic training may decrease the risk for fallings and traumatic injuries among athletes. Twenty athletes (12 girls, 8 boys) and 20 controls (12 girls, 8 boys) ages 10-15 years participated in the current study. All athletes were active in an 8-month physical activity program, 3 times per week for 90 min., specific to basketball, soccer, or athletic training. The control children participated in physical education at school only, with no involvement in organized extracurricular sports. All participants were evaluated for postural balance in three assessments over one year (at 4-mo intervals); the Interactive Balance System machine (Tetrax device) was used to assess balance at three test times (pre-, post-, and 10 min) after a session of a repeated sprint anaerobic test, consisting of 12 × 20 m run starting every 20 sec. The athletes had better postural balance than controls. There were different group patterns of change over the sessions; a significant interaction of session and group indicated that postural balance of the groups differed. The contribution of low sway frequencies (F1) and high sway frequencies (F6) differed between the controls and the athletes group. Results suggested that although athletes had better postural balance, improvement should be encouraged during training over the sessions and seasons, with special awareness of the balance deficit that occurs immediately after anaerobic stress and at the end of the season, to decrease the risk of injuries. PMID:27420320

  1. Longitudinal Study Evaluating Postural Balance of Young Athletes.

    PubMed

    Steinberg, Nili; Nemet, Dan; Pantanowitz, Michal; Zeev, Aviva; Hallumi, Monder; Sindiani, Mahmood; Meckel, Yoav; Eliakim, Alon

    2016-02-01

    Repeated anaerobic conditions during athletic performance may cause general and local fatigue that result in postural balance deficit. Evidence suggests that improved postural balance during athletic training may decrease the risk for fallings and traumatic injuries among athletes. Twenty athletes (12 girls, 8 boys) and 20 controls (12 girls, 8 boys) ages 10-15 years participated in the current study. All athletes were active in an 8-month physical activity program, 3 times per week for 90 min., specific to basketball, soccer, or athletic training. The control children participated in physical education at school only, with no involvement in organized extracurricular sports. All participants were evaluated for postural balance in three assessments over one year (at 4-mo intervals); the Interactive Balance System machine (Tetrax device) was used to assess balance at three test times (pre-, post-, and 10 min) after a session of a repeated sprint anaerobic test, consisting of 12 × 20 m run starting every 20 sec. The athletes had better postural balance than controls. There were different group patterns of change over the sessions; a significant interaction of session and group indicated that postural balance of the groups differed. The contribution of low sway frequencies (F1) and high sway frequencies (F6) differed between the controls and the athletes group. Results suggested that although athletes had better postural balance, improvement should be encouraged during training over the sessions and seasons, with special awareness of the balance deficit that occurs immediately after anaerobic stress and at the end of the season, to decrease the risk of injuries.

  2. On the Existence of Step-To-Step Breakpoint Transitions in Accelerated Sprinting.

    PubMed

    Ettema, Gertjan; McGhie, David; Danielsen, Jørgen; Sandbakk, Øyvind; Haugen, Thomas

    2016-01-01

    Accelerated running is characterised by a continuous change of kinematics from one step to the next. It has been argued that breakpoints in the step-to-step transitions may occur, and that these breakpoints are an essential characteristic of dynamics during accelerated running. We examined this notion by comparing a continuous exponential curve fit (indicating continuity, i.e., smooth transitions) with linear piecewise fitting (indicating breakpoint). We recorded the kinematics of 24 well trained sprinters during a 25 m sprint run with start from competition starting blocks. Kinematic data were collected for 24 anatomical landmarks in 3D, and the location of centre of mass (CoM) was calculated from this data set. The step-to-step development of seven variables (four related to CoM position, and ground contact time, aerial time and step length) were analysed by curve fitting. In most individual sprints (in total, 41 sprints were successfully recorded) no breakpoints were identified for the variables investigated. However, for the mean results (i.e., the mean curve for all athletes) breakpoints were identified for the development of vertical CoM position, angle of acceleration and distance between support surface and CoM. It must be noted that for these variables the exponential fit showed high correlations (r2>0.99). No relationship was found between the occurrences of breakpoints for different variables as investigated using odds ratios (Mantel-Haenszel Chi-square statistic). It is concluded that although breakpoints regularly appear during accelerated running, these are not the rule and thereby unlikely a fundamental characteristic, but more likely an expression of imperfection of performance.

  3. On the Existence of Step-To-Step Breakpoint Transitions in Accelerated Sprinting

    PubMed Central

    McGhie, David; Danielsen, Jørgen; Sandbakk, Øyvind; Haugen, Thomas

    2016-01-01

    Accelerated running is characterised by a continuous change of kinematics from one step to the next. It has been argued that breakpoints in the step-to-step transitions may occur, and that these breakpoints are an essential characteristic of dynamics during accelerated running. We examined this notion by comparing a continuous exponential curve fit (indicating continuity, i.e., smooth transitions) with linear piecewise fitting (indicating breakpoint). We recorded the kinematics of 24 well trained sprinters during a 25 m sprint run with start from competition starting blocks. Kinematic data were collected for 24 anatomical landmarks in 3D, and the location of centre of mass (CoM) was calculated from this data set. The step-to-step development of seven variables (four related to CoM position, and ground contact time, aerial time and step length) were analysed by curve fitting. In most individual sprints (in total, 41 sprints were successfully recorded) no breakpoints were identified for the variables investigated. However, for the mean results (i.e., the mean curve for all athletes) breakpoints were identified for the development of vertical CoM position, angle of acceleration and distance between support surface and CoM. It must be noted that for these variables the exponential fit showed high correlations (r2>0.99). No relationship was found between the occurrences of breakpoints for different variables as investigated using odds ratios (Mantel-Haenszel Chi-square statistic). It is concluded that although breakpoints regularly appear during accelerated running, these are not the rule and thereby unlikely a fundamental characteristic, but more likely an expression of imperfection of performance. PMID:27467387

  4. Time interval moderates the relationship between psyching-up and actual sprint performance.

    PubMed

    Hammoudi-Nassib, Sarra; Chtara, Moktar; Nassib, Sabri; Briki, Walid; Hammoudi-Riahi, Sabra; Tod, David; Chamari, Karim

    2014-11-01

    This study attempted to test whether the strongest effect of psyching-up (PU) strategy on actual sprint performance can be observed when the strategy is used immediately (or almost) before performance compared with when there is a delay between PU and performance. To do so, 16 male sprinters (age, 20.6 ± 1.3 years; body mass, 77.5 ± 7.1 kg; height, 180.8 ± 5.6 cm) were enrolled in a counterbalanced experimental design in which participants were randomly assigned to 10 sessions (2 [Experimental Condition: imagery vs. distraction] × 5 [Time Intervals: no interval, 1 minute, 2 minutes, 3 minutes, and 5 minutes]). Before performing the experimental tasks, participants rated: (a) the Hooper index, (b) their degree of self-confidence, and (c) after the completion of the experimental test; they rated their perceived effort. Findings showed that the imagery significantly improved sprint performance. Specifically, the imagery enhanced performance on the phase of acceleration (0-10 m) and on the overall sprint (0-30 m) when used immediately before performance and at 1- and 2-minute intervals but not for 3- and 5-minute intervals. These findings support the hypothesis that the potential effect of the PU strategy on performance vanishes over time. The pre-experimental task Hooper and self-efficacy indexes did not change across the 10 experimental sessions, reinforcing the view that the observed performance changes were directly caused by the experimental manipulation and not through any altered status of the athletes (self-efficacy, fatigue/recovery, and stress). The potential mechanisms underlying such a process and practical applications are discussed.

  5. Performance tolerance and boat set-up in elite sprint kayaking.

    PubMed

    Ong, Kuan; Elliott, Bruce; Ackland, Tim; Lyttle, Andrew

    2006-01-01

    The aim of this study was to examine the inter-relationship between athlete morphology, equipment set-up and performance in elite sprint kayaking. Correlations applied to data from the 2000 Olympics were used to select the most important links between morphology and boat set-up--paddle grip width and foot-bar distance. Associations between body size and the above selected equipment set-ups were calculated using a Pearson correlation matrix, to facilitate the logical selection of independent variables as input for regression analyses. Significant (p < 0.01) regression equations were developed for the prediction of foot-bar distance (r2 = 0.589: standard error of estimate (SEE) = 4.48) and paddle grip width (r2 = 0.541: SEE = 3.08). Three national-standard sprint kayakers used their preferred set-up together with modifications of their predicted set-up, derived from Olympic data, to test performance tolerance in sprint kayaking. Mean coefficients of multiple determination over three trials for the three paddlers of 0.91, 0.91 and 0.92 for left paddle force, right paddle force, and paddle angle at water entry, respectively, were recorded when using their preferred set-up. These data showed that the paddlers produce consistent patterns of motion. The intervention of altering the boat set-up resulted in varying changes to boat speed. The mean preferred speed for the three paddlers of 4.47 m/s was reduced by 0.07 and 0.10 m/s when the above boat set-up was modified to a predicted and 'predicted plus one standard deviation'respectively. These changes in boat speed were the result of alterations in the mechanics of paddling technique.

  6. What is the Safest Sprint Starting Position for American Football Players?

    PubMed Central

    Bonnechere, Bruno; Beyer, Benoit; Rooze, Marcel; Sint, Jan Serge Van

    2014-01-01

    The main objective of this study was to perform a biomechanical analysis of three different sprint start patterns to determine the safest position in term of neck injury and Sport-Related Concussion (SRC). The second objective was to collect data on the learning process effect between football players and non-players. Three different sprint initial positions adopted by football players were studied (i.e., 4-, 3- and 2-point positions). Twenty five young healthy males, including 12 football players, participated to this study. A stereophotogrammetric system (i.e., Vicon) was used to record motion patterns and body segments positions. Various measurements related to head and trunk orientation, and player field-of-view were obtained (e.g., head height, trunk bending, time to reach upright position, head speed (vertical direction) and body speed (horizontal direction)). Learning process was found to have no influence on studied parameters. Head redress is also delayed when adopting a 4-point position leading to a reduce field-of-view during the start and increasing therefore the probability of collision. Concerning the three different positions, the 4-point position seems to be the more dangerous because leading to higher kinetic energy than the 2- and 3-point start positions. This study proposes a first biomechanical approach to understand risk/benefit balance for athletes for those three different start positions. Results suggested that the 4-point position is the most risky for football players. Key points Motion analysis and biomechanical analysis of the initial start position of the sprint could be used to increase the safety of the football players. Analysis of kinematic and trajectory of the head and the time to reach the upright position could be used to determine whether or not a player can return to play after concussion. A balance needs to be found between player’s safety (2-point start) and speed (4-point start). PMID:24790500

  7. The Relationship between Coach Leadership, the Coach-Athlete Relationship, Team Success, and the Positive Developmental Experiences of Adolescent Soccer Players

    ERIC Educational Resources Information Center

    Vella, Stewart A.; Oades, Lindsay G.; Crowe, Trevor P.

    2013-01-01

    Background: The goals of participation youth sports are primarily concerned with the facilitation of positive youth development as opposed to outright success. Consequently, there are strong theoretical and empirical links between sports coaching and athlete development. Transformational leadership behaviours, in particular, have been…

  8. Timing of neuromuscular activation of the quadriceps and hamstrings prior to landing in high school male athletes, female athletes, and female non-athletes.

    PubMed

    Medina, Jennifer M; Valovich McLeod, Tamara C; Howell, Suzanne K; Kingma, Jackie J

    2008-08-01

    There is a discrepancy between males and females in regards to lower extremity injury rates, particularly at the knee [Agel, J., Arendt, E.A., Bershadsky, B., 2005. Anterior cruciate ligament injury in National Collegiate Athletic Association basketball and soccer: a 13-year review. American Journal of Sports Medicine 33, (4) 524-530]. Gender differences in neuromuscular recruitment characteristics of the muscles that stabilize the knee are often implicated as a factor in this discrepancy. There is considerable research in the area of gender differences in regards to neuromuscular characteristics of the lower extremity in response to perturbation; however, most studies have been performed on the adult population only. Additionally, there is no consensus as to the gender differences that have been demonstrated. The purpose of this study was to compare muscular preactivation of selected lower extremity muscles (vastus medialis, rectus femoris, and medial/lateral hamstrings) in adolescent female basketball athletes, male basketball athletes, and female non-athletes in response to a drop landing. Subjects in the female non-athlete group recruited rectus femoris significantly slower than both the female athlete and male athlete groups (619.9=588.5>200.1ms prior to ground contact). The female non-athlete group also demonstrated a significantly slower vastus medialis compared to the female athlete group (127.1 vs 408.1ms), but not significantly slower than the male athlete group (127.1 vs 275.7ms). There were no differences between female athletes and male athletes for time to initial contraction of any muscle groups. No differences were found among the groups for medial or lateral hamstring activation. This study demonstrates that physical conditioning due to basketball participation appears to affect neuromuscular recruitment in adolescents and reveals a necessity to find alternate methods of training the hamstrings for improved neuromuscular capabilities to prevent

  9. The Relationship Between Muscle Strength, Anaerobic Performance, Agility, Sprint Ability and Vertical Jump Performance in Professional Basketball Players

    PubMed Central

    Alemdaroğlu, Utku

    2012-01-01

    The purpose of this study was to investigate the relationship between isokinetic knee strength, anaerobic performance, sprinting ability, agility and vertical jump performance in first division basketball players. Twelve male first division basketball players participated in this study. The mean age was 25.1 ± 1.7 yrs; mean body height 194.8 ± 5.7 cm; mean body mass 92.3± 9.8 kg; mean PBF 10.1± 5.1; and mean VO2max 50.55 ± 6.7 ml/kg/min Quadriceps and hamstrings were measured at 60° and 180°/s, anaerobic performance was evaluated using the Wingate anaerobic power test, sprint ability was determined by single sprint performance (10–30 m), jump performance was evaluated by countermovement (CMJ) and squat jump (SJ) tests and agility performance was measured using the T drill agility test. Quadriceps strength was significantly correlated with peak power at all contraction velocities. However, for mean power, significant correlation was only found between the 60° left and 180° right knee quadriceps measurements. No measure of strength was significantly related to the measurements from/results of field tests. Moreover, strong relations were found between the performance of athletes in different field tests (p< 0.05). The use of correlation analysis is the limitation of the this study. PMID:23486566

  10. The relationship between muscle strength, anaerobic performance, agility, sprint ability and vertical jump performance in professional basketball players.

    PubMed

    Alemdaroğlu, Utku

    2012-03-01

    The purpose of this study was to investigate the relationship between isokinetic knee strength, anaerobic performance, sprinting ability, agility and vertical jump performance in first division basketball players. Twelve male first division basketball players participated in this study. The mean age was 25.1 ± 1.7 yrs; mean body height 194.8 ± 5.7 cm; mean body mass 92.3± 9.8 kg; mean PBF 10.1± 5.1; and mean VO2max 50.55 ± 6.7 ml/kg/min Quadriceps and hamstrings were measured at 60° and 180°/s, anaerobic performance was evaluated using the Wingate anaerobic power test, sprint ability was determined by single sprint performance (10-30 m), jump performance was evaluated by countermovement (CMJ) and squat jump (SJ) tests and agility performance was measured using the T drill agility test. Quadriceps strength was significantly correlated with peak power at all contraction velocities. However, for mean power, significant correlation was only found between the 60° left and 180° right knee quadriceps measurements. No measure of strength was significantly related to the measurements from/results of field tests. Moreover, strong relations were found between the performance of athletes in different field tests (p< 0.05). The use of correlation analysis is the limitation of the this study.

  11. Jocks, Gender, Binge Drinking, and Adolescent Violence

    ERIC Educational Resources Information Center

    Miller, Kathleen E.; Melnick, Merrill J.; Farrell, Michael P.; Sabo, Donald F.; Barnes, Grace M.

    2006-01-01

    Previous research has suggested a link between athletic involvement and elevated levels of adolescent violence outside the sport context. The present study expanded on this literature by positing differences in the sport-violence relationship across dimensions of athletic involvement (athletic participation vs. jock identity), type of violence…

  12. Vertical and leg stiffness and stretch-shortening cycle changes across maturation during maximal sprint running.

    PubMed

    Rumpf, Michael C; Cronin, John B; Oliver, Jon L; Hughes, Michael G

    2013-08-01

    The purpose of this study was to investigate whether vertical and leg stiffness, and stretch-shortening cycle (SSC) ability differed in developing athletes of various maturity status during maximal sprint running. Seventy-four male participants between 8 and 16 years of age were categorized into pre-, mid- or post-peak height velocity (PHV) and sprinted for 30 meters on a non-motorized treadmill. Dimensionless vertical stiffness increased significantly (p<.05) from pre-, to mid- and post-PHV state, while dimensionless leg stiffness was significantly higher in post- compared to mid- (18.4%) and pre-PHV participants (44.5%). Eccentric power was significantly lower in pre- compared to the mid- and post-PHV participants. Concentric power increased from pre- to mid- and post-PHV state. An analysis of covariance revealed no significant differences between all groups in dimensionless vertical and leg stiffness, eccentric and concentric time and power when controlling for years from PHV (maturation). Eccentric or concentric power, were found to be the best predictors of maximum velocity across all maturation groups (r2=.37-.68). It seems that maturation affects the ability to absorb and produce power and furthermore these variables are important predictors of maximal running velocity.

  13. Effects of weighted sled towing on ground reaction force during the acceleration phase of sprint running.

    PubMed

    Kawamori, Naoki; Newton, Robert; Nosaka, Ken

    2014-01-01

    Athletes use weighted sled towing to improve sprint ability, but little is known about its biomechanics. The purpose of this study was to investigate the effect of weighted sled towing with two different loads on ground reaction force. Ten physically active men (mean ± SD: age 27.9 ± 1.9 years; stature 1.76 ± 0.06 m; body mass 80.2 ± 9.6 kg) performed 5 m sprints under three conditions; (a) unresisted, (b) towing a sled weighing 10% of body mass (10% condition) and (c) towing a sled weighing 30% of body mass (30% condition). Ground reaction force data during the second ground contact after the start were recorded and compared across the three conditions. No significant differences between the unresisted and 10% conditions were evident, whereas the 30% condition resulted in significantly greater values for the net horizontal and propulsive impulses (P < 0.05) compared with the unresisted condition due to longer contact time and more horizontal direction of force application to the ground. It is concluded that towing a sled weighing 30% of body mass requires more horizontal force application and increases the demand for horizontal impulse production. In contrast, the use of 10% body mass has minimal impact on ground reaction force.

  14. Athlete and Non-Athlete Adjustment to College

    ERIC Educational Resources Information Center

    Drum, Jennifer; Ladda, Shawn; Geary, Colette; Fitzpatrick, Corine

    2014-01-01

    This study examined college adjustment between athletes and non-athletes at Manhattan College, a medium-sized college participating in NCAA Division I athletics located in the Bronx, New York. Groups included a total of fifty-two athletes, fifty-six non-athletes, twenty-five female athletes, twenty-seven male athletes, twenty-six female…

  15. Effects of Warm-Up Stretching Exercises on Sprint Performance

    ERIC Educational Resources Information Center

    Makaruk, Hubert; Makaruk, Beata; Kedra, Stanislaw

    2008-01-01

    Study aim: To assess direct effects of warm-up consisting of static and dynamic stretching exercises on sprint results attained by students differing in sprint performance. Material and methods: A group of 24 male and 19 female physical education students, including 12 and 9 sprinters, respectively. They performed warm-ups consisting of dynamic…

  16. Overview (looking west) of remote sprint launch site #2 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Overview (looking west) of remote sprint launch site #2 - Stanley R. Mickelsen Safeguard Complex, Remote Sprint Launch Site No. 2, West of Mile Marker 220 on State Route 1, 6.0 miles North of Langdon, ND, Nekoma, Cavalier County, ND

  17. Athletes' opinions of food provision at the 2010 Delhi Commonwealth Games: the influence of culture and sport.

    PubMed

    Burkhart, Sarah J; Pelly, Fiona E

    2013-02-01

    The aim of this study was to investigate whether athletes' opinion of food provision in the main dining hall of the athletes' village at the Delhi 2010 Commonwealth Games varied according to cultural background, sport, stage of competition, and previous experience at similar events. A previously developed questionnaire was distributed over 3 meal periods to 351 athletes dining in the main dining hall during the course of the games (Sept. 23 to Oct. 4, 2010). Despite the challenges of food provision in a non-Western region, the availability of food and beverage items was rated highly. However, athletes from Western regions tended to rate food-provision qualities lower than athletes from non-Western regions. Most athletes found it easy to find items to meet their nutrition needs; however, requests for sports foods, snacks, and culturally specific items were received. Power/sprint athletes were more critical of the food provision, whereas athletes from aesthetic sports tended to rate it more highly. Athletes farther from competition gave higher ratings for taste, while athletes who had more experience in this type of environment also tended to be more critical of the food provision. Overall daily mean opinion scores for taste and menu variety decreased over the games period. The results of this study can help organizers and caterers ensure that appropriate food and beverage are provided for athletes at major competition events.

  18. Joint Cooling does not Hinder Athletic Performance during High-intensity Intermittent Exercise.

    PubMed

    Kim, H; Lee, D; Choi, H-M; Park, J

    2016-07-01

    We examined the effects of ankle and knee joint cooling on 20-m sprint times and maximal vertical jump heights during high-intensity intermittent exercise. 21 healthy collegiate male basketball (n=14) and handball players (n=7) underwent 3 experimental sessions. Each session consisted of four 15-min quarters of high-intensity intermittent exercises including various intensities of 20-m shuttle running and jumping. A 20-min bilateral joint cooling (ankle, knee, or control-no cooling: in a counterbalanced order) was applied before quarters 1 and 3. After joint cooling, no warm-up activity other than the exercise protocol was given. The 20-m sprint times and maximal vertical jump heights in each experimental session were recorded at baseline (prior to quarter-1) and during each quarter. To test joint cooling effects over time, we performed 3×5 mixed model ANOVAs. Neither ankle nor knee joint cooling changed 20-m sprint times (F8,280=1.45; p=0.18) or maximal vertical jump heights (F8,280=0.76; p=0.64). However, a trend was observed in which joint cooling immediately decreased (quarters 1 and 3) but active warm-up for approximately 20 min improved 20-min sprint times (quarters 2 and 4). Our study suggests that athletic performance such as sprinting and jumping are not altered by joint cooling applied prior to or during high-intensity intermittent exercise. PMID:27119166

  19. Joint Cooling does not Hinder Athletic Performance during High-intensity Intermittent Exercise.

    PubMed

    Kim, H; Lee, D; Choi, H-M; Park, J

    2016-07-01

    We examined the effects of ankle and knee joint cooling on 20-m sprint times and maximal vertical jump heights during high-intensity intermittent exercise. 21 healthy collegiate male basketball (n=14) and handball players (n=7) underwent 3 experimental sessions. Each session consisted of four 15-min quarters of high-intensity intermittent exercises including various intensities of 20-m shuttle running and jumping. A 20-min bilateral joint cooling (ankle, knee, or control-no cooling: in a counterbalanced order) was applied before quarters 1 and 3. After joint cooling, no warm-up activity other than the exercise protocol was given. The 20-m sprint times and maximal vertical jump heights in each experimental session were recorded at baseline (prior to quarter-1) and during each quarter. To test joint cooling effects over time, we performed 3×5 mixed model ANOVAs. Neither ankle nor knee joint cooling changed 20-m sprint times (F8,280=1.45; p=0.18) or maximal vertical jump heights (F8,280=0.76; p=0.64). However, a trend was observed in which joint cooling immediately decreased (quarters 1 and 3) but active warm-up for approximately 20 min improved 20-min sprint times (quarters 2 and 4). Our study suggests that athletic performance such as sprinting and jumping are not altered by joint cooling applied prior to or during high-intensity intermittent exercise.

  20. Athletics and the Law.

    ERIC Educational Resources Information Center

    Appenzeller, Herb

    This book answers questions concerning athletics and the law. The chapters include trends in litigation, disruptive behavior, the changing attitude of the court toward married athletes, training rules, and good conduct codes. They include the problem of athletic travel, the changing role of state athletic associations with their diverse rules,…

  1. Collegiate Athletics Highlights.

    ERIC Educational Resources Information Center

    St. John, Eric

    1999-01-01

    Highlights 15 trends/events in black college athletics, including championship coaches, Black Coaches Association, eligibility issues, disclosure of athlete graduation rates, athletics resource allocation, early adoption of professional athlete status, success of the Women's National Basketball Association, lack of black access to certain sports,…

  2. Overuse injuries of the olecranon in adolescents.

    PubMed

    Parr, Thomas J; Burns, Travis C

    2003-11-01

    Overuse injuries are common in elite adolescent athletes due to intensive training demands. Overuse injuries of the olecranon have been divided into true stress fractures and osteochondroses. This article presents a third overuse injury, painful intraosseous edema, in elite adolescent athletes.

  3. 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.

  4. The acute effects of green tea and carbohydrate coingestion on systemic inflammation and oxidative stress during sprint cycling.

    PubMed

    Suzuki, Katsuhiko; Takahashi, Masaki; Li, Chia-Yang; Lin, Shiuan-Pey; Tomari, Miki; Shing, Cecilia M; Fang, Shih-Hua

    2015-10-01

    Green tea (Camellia sinensis) has anti-oxidative and anti-inflammatory effects, which may be beneficial to athletes performing high-intensity exercise. This study investigated the effects of carbohydrate and green tea coingestion on sprint cycling performance and associated oxidative stress and immunoendocrine responses to exercise. In a crossover design, 9 well-trained male cyclists completed 3 sets of 8 repetitions of 100-m uphill sprint cycling while ingesting green tea and carbohydrate (TEA) (22 mg/kg body mass catechins, 6 mg/kg body mass caffeine, 230 mg/kg glucose, and 110 mg/kg fructose) or carbohydrate only (CHO) (230 mg/kg body mass glucose and 110 mg/kg body mass fructose) during each 10-min recovery period between sets. Blood samples were collected before exercise, 10 min after exercise, and 14 h after exercise. There was no effect of acute TEA ingestion on cycling sprint performance (p = 0.29), although TEA maintained postexercise testosterone and lymphocyte concentrations, which decreased significantly in the CHO group (p < 0.001). While there was a trend for lower postexercise neutrophil count with TEA (p = 0.05), there were no significant differences between TEA and CHO for circulating cytokines (p > 0.20), markers of oxidative stress and antioxidant capacity (p > 0.17), adiponectin concentration (p = 0.60), or muscle damage markers (p > 0.64). While acute green tea ingestion prevents the postexercise decrease in testosterone and lymphocytes, it does not appear to benefit cycling sprint performance or reduce markers of oxidation and inflammation when compared with carbohydrate alone. PMID:26319564

  5. Effect of the HamSprint Drills training programme on lower limb neuromuscular control in Australian football players.

    PubMed

    Cameron, Matthew L; Adams, Roger D; Maher, Chris G; Misson, David

    2009-01-01

    This study examined the effect of the HamSprint Drills training programme and conventional football practice warm-up on lower limb neuromuscular control. The purpose-built active movement extent discrimination apparatus was used to assess lower limb neuromuscular control in 29 footballers from one professional Australian Football League club. Without vision of the contact point, participants performed 40 backward swing movement trials with each leg and made a judgment of the magnitude of each movement. Scores representing the ability to discriminate between different movement extents were calculated as the area under the player's receiver operating characteristic curve, constructed using non-parametric signal detection theory methods. Participants were randomized to either an intervention or control group that performed different procedures in the warm-up prior to football practice sessions over a 6-week period, and then were re-tested. The intervention group performed the HamSprint programme-drills specific to the improvement of running technique, co-ordination and hamstring function. The control group performed their usual warm-up of stretching, running, and increasingly intense football drills. Backward leg swing extent discrimination was significantly better in players following the 6-week HamSprint programme when compared to discrimination scores of players who performed their usual practice warm-up only. Significant improvement was observed in lower limb neuromuscular control in movements similar to the late-swing early stance phase of running. The HamSprint programme can therefore improve control in a specific aspect of sensorimotor system performance, and this may be useful particularly in athletes who have lower function levels or those deemed at risk of hamstring injury.

  6. Application of a body-weight-supporting kite for sprint running.

    PubMed

    Kratky, Sascha; Müller, Erich

    2013-11-01

    Improvements in sprint performance at the top level require adaptations concerning force application because ground contact time diminishes with increasing velocity. Applied training methods and devices must provoke appropriate stimuli. A knowledge about positive and negative effects of these stimuli is vital for coaches. The purpose of this study was to determine the angle of attack and lifting and retarding forces of a novel sprint training device that supports the athlete's body weight (BW), thereby decreasing ground contact time during sprints. Three different kite sizes (1.10, 1.75, 2.25 m) were investigated. A bicycle was used to accelerate the National Aeronautics and Space Administration (NASA) parawings (NPW-120, NPW-150, and NPW-170) on an indoor track to acquire data at velocities between 6.5 and 10.5 m · s. During a 5-m interval of constant speed, the resultant force of the kite was recorded on a portable computer by a load cell. The angle of attack was determined by a high-speed camera, and the mean velocity in the 5-m sector was measured by a laser gauge. Lifting and retarding forces were derived from the resultant force and angle of attack. Quadratic regression equations for lifting and retarding forces, depending on the velocity, were calculated for all 3 NPWs. A clear difference (p < 0.001) depending on the kite size was revealed for lifting and retarding forces. These forces also indicated high correlation coefficients related to velocity (r > 0.98; p < 0.001), whereas the angle of attack remained almost constant across the entire velocity range in all NPWs, yielding a lift-to-drag ratio of 2.35. Because of the kite's small retarding forces, we recommend the application of the NPW during the high-speed phase of sprinting with lifting force probably counteracting adverse effects. By adding a towing system, the retarding force can be fine tuned, erased, or turned into overspeed assistance, thereby emphasizing BW support.

  7. Differences in 200-m sprint running performance between outdoor and indoor venues.

    PubMed

    Ferro, Amelia; Floria, Pablo

    2013-01-01

    Athletes' times in 200-m indoor races are greater than in outdoor races. The purpose of this study was to determine which 50-m sections were slower indoors than outdoors in 200-m sprint events and by how much. Using 2-dimensional photogrammetric techniques, a 50-m split-time analysis was made of the performance of 17 men and 16 women, all well-trained athletes, at 4 national competitions held over 5 years. The time taken to run the 0- to 50-m section was longer indoors than outdoors in women (6.89 ± 0.12 vs. 6.75 ± 0.04 seconds; p < 0.05) and in men (6.18 ± 0.10 vs. 6.08 ± 0.09 seconds; p < 0.05). Similarly, both women and men took more time to run the 100- to 150-m section indoors (6.03 ± 0.15 vs. 5.84 ± 0.06 seconds; p < 0.01, respectively) than outdoors (5.26 ± 0.15 vs. 5.06 ± 0.07 seconds; p < 0.01, respectively). Both sections indoors were run mostly on the curve. However, significant differences were not found in the split times for 50-100 and 150-200 m in either sex. In both categories, the relative average velocity (RAV), percentage of average velocity relative to the maximum velocity reached in the fastest section (50-100 m), was about 3% lower indoors than outdoors in 100- to 150-m section. The athletes' lower capacity to develop speed indoors could be caused specifically, by the curved 0- to 50-m and 100- to 150-m sections of the indoor track. Coaches could use these data as reference values there being few published data from high-level competitions. The RAV could be used by coaches to compare results among athletes of different levels and sexes.

  8. Differences in 200-m sprint running performance between outdoor and indoor venues.

    PubMed

    Ferro, Amelia; Floria, Pablo

    2013-01-01

    Athletes' times in 200-m indoor races are greater than in outdoor races. The purpose of this study was to determine which 50-m sections were slower indoors than outdoors in 200-m sprint events and by how much. Using 2-dimensional photogrammetric techniques, a 50-m split-time analysis was made of the performance of 17 men and 16 women, all well-trained athletes, at 4 national competitions held over 5 years. The time taken to run the 0- to 50-m section was longer indoors than outdoors in women (6.89 ± 0.12 vs. 6.75 ± 0.04 seconds; p < 0.05) and in men (6.18 ± 0.10 vs. 6.08 ± 0.09 seconds; p < 0.05). Similarly, both women and men took more time to run the 100- to 150-m section indoors (6.03 ± 0.15 vs. 5.84 ± 0.06 seconds; p < 0.01, respectively) than outdoors (5.26 ± 0.15 vs. 5.06 ± 0.07 seconds; p < 0.01, respectively). Both sections indoors were run mostly on the curve. However, significant differences were not found in the split times for 50-100 and 150-200 m in either sex. In both categories, the relative average velocity (RAV), percentage of average velocity relative to the maximum velocity reached in the fastest section (50-100 m), was about 3% lower indoors than outdoors in 100- to 150-m section. The athletes' lower capacity to develop speed indoors could be caused specifically, by the curved 0- to 50-m and 100- to 150-m sections of the indoor track. Coaches could use these data as reference values there being few published data from high-level competitions. The RAV could be used by coaches to compare results among athletes of different levels and sexes. PMID:22395263

  9. Effect of the number of sprint repetitions on the variation of blood lactate concentration in repeated sprint sessions.

    PubMed

    Gharbi, Z; Dardouri, W; Haj-Sassi, R; Castagna, C; Chamari, K; Souissi, N

    2014-06-01

    The aim of the present study was to examine the effect of number of sprint repetitions on the variation of blood lactate concentration (blood [La]) during different repeated-sprint sessions in order to find the appropriate number of sprint repetitions that properly simulates the physiological demands of team sport competitions. Twenty male team-sport players (age, 22.2 ± 2.9 years) performed several repeated-sprint sessions (RSS) consisting of 1, 2, 3, 4, 5, 9, or 10 repetitions of 30 m shuttle sprints (2 × 15 m) with 30 s recovery in between. The blood [La] was obtained after 3 min of recovery at the end of each RSS. The present study showed that for RSS of 3 sprints (RSS3) there was a high increase (p<0.001) in blood [La], which reached approximately fivefold resting values (9.4±1.7 mmol · l(-1)) and then remained unchanged for the RSS of 4 and 5 sprints (9.6±1.4 and 10.5±1.9 mmol · l(-1), p=0.96 and 0.26, respectively). After RSS9 and RSS10 blood [La] further significantly increased to 12.6 and 12.7 mmol · l(-1), p<0.001, respectively. No significant difference was found between RSS3, RSS4 and RSS5 for the percentage of sprint speed decrement (Sdec) (1.5±1.2; 2.0±1.1 and 2.6±1.4%, respectively). There was also no significant difference between RSS9 and RSS10 for Sdec (3.9±1.3% and 4.5±1.4%, respectively). In conclusion, the repeated-sprint protocol composed of 5 shuttle sprint repetitions is more representative of the blood lactate demands of the team sports game intensity. PMID:24899781

  10. EFFECT OF THE NUMBER OF SPRINT REPETITIONS ON THE VARIATION OF BLOOD LACTATE CONCENTRATION IN REPEATED SPRINT SESSIONS

    PubMed Central

    Dardouri, W.; Haj-Sassi, R.; Castagna, C.; Chamari, K.; Souissi, N.

    2014-01-01

    The aim of the present study was to examine the effect of number of sprint repetitions on the variation of blood lactate concentration (blood [La]) during different repeated-sprint sessions in order to find the appropriate number of sprint repetitions that properly simulates the physiological demands of team sport competitions. Twenty male team-sport players (age, 22.2 ± 2.9 years) performed several repeated-sprint sessions (RSS) consisting of 1, 2, 3, 4, 5, 9, or 10 repetitions of 30 m shuttle sprints (2 × 15 m) with 30 s recovery in between. The blood [La] was obtained after 3 min of recovery at the end of each RSS. The present study showed that for RSS of 3 sprints (RSS3) there was a high increase (p<0.001) in blood [La], which reached approximately fivefold resting values (9.4±1.7 mmol · l−1) and then remained unchanged for the RSS of 4 and 5 sprints (9.6±1.4 and 10.5±1.9 mmol · l−1, p=0.96 and 0.26, respectively). After RSS9 and RSS10 blood [La] further significantly increased to 12.6 and 12.7 mmol · l−1, p<0.001, respectively. No significant difference was found between RSS3, RSS4 and RSS5 for the percentage of sprint speed decrement (Sdec) (1.5±1.2; 2.0±1.1 and 2.6±1.4%, respectively). There was also no significant difference between RSS9 and RSS10 for Sdec (3.9±1.3% and 4.5±1.4%, respectively). In conclusion, the repeated-sprint protocol composed of 5 shuttle sprint repetitions is more representative of the blood lactate demands of the team sports game intensity. PMID:24899781

  11. Effect of the number of sprint repetitions on the variation of blood lactate concentration in repeated sprint sessions.

    PubMed

    Gharbi, Z; Dardouri, W; Haj-Sassi, R; Castagna, C; Chamari, K; Souissi, N

    2014-06-01

    The aim of the present study was to examine the effect of number of sprint repetitions on the variation of blood lactate concentration (blood [La]) during different repeated-sprint sessions in order to find the appropriate number of sprint repetitions that properly simulates the physiological demands of team sport competitions. Twenty male team-sport players (age, 22.2 ± 2.9 years) performed several repeated-sprint sessions (RSS) consisting of 1, 2, 3, 4, 5, 9, or 10 repetitions of 30 m shuttle sprints (2 × 15 m) with 30 s recovery in between. The blood [La] was obtained after 3 min of recovery at the end of each RSS. The present study showed that for RSS of 3 sprints (RSS3) there was a high increase (p<0.001) in blood [La], which reached approximately fivefold resting values (9.4±1.7 mmol · l(-1)) and then remained unchanged for the RSS of 4 and 5 sprints (9.6±1.4 and 10.5±1.9 mmol · l(-1), p=0.96 and 0.26, respectively). After RSS9 and RSS10 blood [La] further significantly increased to 12.6 and 12.7 mmol · l(-1), p<0.001, respectively. No significant difference was found between RSS3, RSS4 and RSS5 for the percentage of sprint speed decrement (Sdec) (1.5±1.2; 2.0±1.1 and 2.6±1.4%, respectively). There was also no significant difference between RSS9 and RSS10 for Sdec (3.9±1.3% and 4.5±1.4%, respectively). In conclusion, the repeated-sprint protocol composed of 5 shuttle sprint repetitions is more representative of the blood lactate demands of the team sports game intensity.

  12. A rise in peak performance age in female athletes.

    PubMed

    Elmenshawy, Ahmed R; Machin, Daniel R; Tanaka, Hirofumi

    2015-06-01

    It was reported in 1980s that ages at which peak performance was observed had remained remarkably stable in the past century, although absolute levels of athletic performance increased dramatically for the same time span. The emergence of older (masters) athletes in the past few decades has changed the demographics and age-spectrum of Olympic athletes. The primary aim of the present study was to determine whether the ages at which peak performance was observed had increased in the recent decades. The data spanning 114 years from the first Olympics (1898) to the most recent Olympics (2014) were collected using the publically available data. In the present study, ages at which Olympic medals (gold, silver, and bronze) were won were used as the indicators of peak performance age. Track and field, swimming, rowing, and ice skating events were analyzed. In men, peak performance age did not change significantly in most of the sporting events (except in 100 m sprint running). In contrast, peak performance ages in women have increased significantly since 1980s and consistently in all the athletic events examined. Interestingly, as women's peak performance age increased, they became similar to men's peak ages in many events. In the last 20-30 years, ages at which peak athletic performance is observed have increased in women but not in men.

  13. A rise in peak performance age in female athletes.

    PubMed

    Elmenshawy, Ahmed R; Machin, Daniel R; Tanaka, Hirofumi

    2015-06-01

    It was reported in 1980s that ages at which peak performance was observed had remained remarkably stable in the past century, although absolute levels of athletic performance increased dramatically for the same time span. The emergence of older (masters) athletes in the past few decades has changed the demographics and age-spectrum of Olympic athletes. The primary aim of the present study was to determine whether the ages at which peak performance was observed had increased in the recent decades. The data spanning 114 years from the first Olympics (1898) to the most recent Olympics (2014) were collected using the publically available data. In the present study, ages at which Olympic medals (gold, silver, and bronze) were won were used as the indicators of peak performance age. Track and field, swimming, rowing, and ice skating events were analyzed. In men, peak performance age did not change significantly in most of the sporting events (except in 100 m sprint running). In contrast, peak performance ages in women have increased significantly since 1980s and consistently in all the athletic events examined. Interestingly, as women's peak performance age increased, they became similar to men's peak ages in many events. In the last 20-30 years, ages at which peak athletic performance is observed have increased in women but not in men. PMID:26022534

  14. Are "classical" tests of repeated-sprint ability in football externally valid? A new approach to determine in-game sprinting behaviour in elite football players.

    PubMed

    Schimpchen, Jan; Skorski, Sabrina; Nopp, Stephan; Meyer, Tim

    2016-01-01

    The aim of this study was to investigate the occurrence of repeated sprinting bouts in elite football. Furthermore, the construct validity of current tests assessing repeated-sprint ability (RSA) was analysed using information of sprinting sequences as they actually occurred during match-play. Sprinting behaviour in official competition was analysed for 19 games of the German national team between August 2012 and June 2014. A sprinting threshold was individually calculated based on the peak velocity reached during in-game sprinting. Players performed 17.2 ± 3.9 sprints per game and during the entire 19 games a total of 35 bouts of repeated sprinting (a minimum of three consecutive sprints with a recovery duration <30 s separating efforts). This averages one bout of repeated sprinting per player every 463 min. No general decrement in maximal sprinting speed was observed during bouts with up to five consecutive sprints. Results of the present study question the importance of RSA as it is classically defined. They indicate that shorter accelerations are more important in game-specific situations which do not reach speeds necessary to qualify them as sprints. The construct validity of classic tests of RSA in football is not supported by these observations.

  15. Are "classical" tests of repeated-sprint ability in football externally valid? A new approach to determine in-game sprinting behaviour in elite football players.

    PubMed

    Schimpchen, Jan; Skorski, Sabrina; Nopp, Stephan; Meyer, Tim

    2016-01-01

    The aim of this study was to investigate the occurrence of repeated sprinting bouts in elite football. Furthermore, the construct validity of current tests assessing repeated-sprint ability (RSA) was analysed using information of sprinting sequences as they actually occurred during match-play. Sprinting behaviour in official competition was analysed for 19 games of the German national team between August 2012 and June 2014. A sprinting threshold was individually calculated based on the peak velocity reached during in-game sprinting. Players performed 17.2 ± 3.9 sprints per game and during the entire 19 games a total of 35 bouts of repeated sprinting (a minimum of three consecutive sprints with a recovery duration <30 s separating efforts). This averages one bout of repeated sprinting per player every 463 min. No general decrement in maximal sprinting speed was observed during bouts with up to five consecutive sprints. Results of the present study question the importance of RSA as it is classically defined. They indicate that shorter accelerations are more important in game-specific situations which do not reach speeds necessary to qualify them as sprints. The construct validity of classic tests of RSA in football is not supported by these observations. PMID:26580089

  16. Assisted and resisted sprint training in swimming.

    PubMed

    Girold, Sébastien; Calmels, Paul; Maurin, Didier; Milhau, Nicolas; Chatard, Jean-Claude

    2006-08-01

    This study was undertaken to determine whether the resisted-sprint in overstrength (OSt) or the assisted-sprint in overspeed (OSp) could be efficient training methods to increase 100-m front crawl performance. Thirty-seven (16 men, 21 women) competition-level swimmers (mean +/- SD: age 17.5 +/- 3.5 years, height 173 +/- 14 cm, weight 63 +/- 14 kg) were randomly divided into 3 groups: OSt, OSp, and control (C). All swimmers trained 6 days per week for 3 weeks, including 3 resisted or assisted training sessions per week for the groups OSt and OSp respectively. Elastic tubes were used to generate swimming overstrength and overspeed. Three 100-m events were performed before, during, and after the training period. Before each 100-m event, strength of the elbow flexors and extensors was measured with an isokinetic dynamometer. Stroke rate and stroke length were evaluated using the video-recorded 100-m events. In the OSt group, elbow extensor strength, swimming velocity, and stroke rate significantly increased (p < 0.05), while stroke length remained unchanged after the 3-week training period. In the OSp group, stroke rate significantly increased (p < 0.05) and stroke length significantly decreased (p < 0.05) without changes in swimming velocity. No significant variations in the C group were observed. Both OSt and OSp proved to be more efficient than the traditional training program. However, the OSt training program had a larger impact on muscle strength, swimming performance, and stroke technique than the OSp program.

  17. Responses of sex steroid hormones to different intensities of exercise in endurance athletes.

    PubMed

    Sato, Koji; Iemitsu, Motoyuki; Katayama, Keisho; Ishida, Koji; Kanao, Yoji; Saito, Mitsuru

    2016-01-01

    Previous studies have shown that acute exercise elevates sex steroid hormone concentrations in rodents and that sprint exercise increases circulating testosterone in healthy young men. However, the effect of different exercise intensities on sex steroid hormone responses at different levels of physical fitness is still unclear. In this study, we compared circulating sex steroid hormone responses at different exercise intensities in athletes and non-athletes. Eight male endurance athletes and 11 non-athletes performed two 15 min sessions of submaximal exercise at 40 and 70% peak oxygen uptake (V̇(O2peak)), respectively, and exercised at 90% V̇(O2peak) until exhaustion. Venous blood samples were collected during the last minute of each submaximal exercise session and immediately after exhaustion. Acute exercise at 40, 70 and 90% V̇(O2peak) induced significant increases in serum dehydroepiandrosterone (DHEA) and free testosterone concentrations in non-athletes. On the contrary, only 90% V̇O2 peak exercise led to an increase in serum DHEA and free testosterone concentrations in athletes. Serum 5α-dihydrotestosterone concentrations increased with 90% V̇(O2peak) exercise in both athletes and non-athletes. Additionally, serum estradiol concentrations were significantly increased at moderate and high exercise intensities in both athletes and non-athletes. These results indicate that in endurance athletes, serum sex steroid hormone concentrations, especially serum DHEA and 5α-dihydrotestosterone concentrations, increased only with high-intensity exercise, suggesting that different responses of sex steroid hormone secretion are induced by different exercise intensities in individuals with low and high levels of physical fitness. In athletes, therefore, high-intensity exercise may be required to increase circulating sex steroid hormone concentrations.

  18. The effect of athletic clothing aerodynamics upon running speed.

    PubMed

    Kyle, C R; Caiozzo, V J

    1986-10-01

    The purpose of this study was to determine the effect of the wind resistance of athletic clothing upon running speed in sprinting and in distance running. Wind tunnel tests of clothing materials, hair, and shoes show that it is possible to lower the wind resistance of a runner from about 0.5% to over 6% by improved aerodynamics. Mathematical models of sprinting and distance running are developed to predict the effect of lower wind resistance upon race times. By lowering the wind resistance of a runner 2%, the models predict the effect of lower wind resistance upon race times. By lowering the wind resistance of a runner 2%, the models predict time savings from 0.01 s in the 100-m dash to 5.7 s in the marathon. This is the equivalent of lead distances of about 0.1 to 31 m. The sprint model may be used to predict the effect of altitude upon running speed. At the altitude of Mexico City, the model predicts an improvement of 0.08 s in 100 m and 0.16 s in 200 m. This is conservative compared to actual time savings. The results show that it is possible to lower the wind resistance significantly by improving clothing or by trimming or covering the hair, and that a small aerodynamic drag reduction can result in a significant performance increase.

  19. Characteristics of sprint performance in college football players.

    PubMed

    Brechue, William F; Mayhew, Jerry L; Piper, Fontaine C

    2010-05-01

    To investigate sprinting strategy, acceleration and velocity patterns were determined in college football players (n = 61) during performance of a 9.1-, 36.6-, and 54.9-m sprints. Acceleration and velocity were determined at 9.1-m intervals during each sprint. Lower-body strength and power were evaluated by 1 repetition maximum (1-RM) squat, power clean, jerk, vertical jump, standing long jump, and standing triple jump. Sprint times averaged 1.78 +/- 0.11 seconds (9.1 m), 5.18 +/- 0.35 seconds (36.6 m), and 7.40 +/- 0.53 seconds. Acceleration peaked at 9.1 m (2.96 +/- 0.44 m x s(-2)), was held constant at 18.3 m (3.55 +/- 0.0.94 m x s(-2)), and was negative at 27.4 m (-1.02 +/- 0.72 m x s(-2)). Velocity peaked at 18.3 m (8.38 +/- 0.65 m x s(-2)) and decreased slightly, but significantly at 27.4 m (7.55 +/- 0.66 m x s(-2)), associated with the negative acceleration. Measures of lower-body strength were significantly related to acceleration, velocity, and sprint performance only when corrected for body mass. Lower-body strength/BM and power correlated highest with 36.6-m time (rs = -0.55 to -0.80) and with acceleration (strength r = 0.67-0.49; power r = 0.73-0.81) and velocity (strength r = 0.68-0.53; power r = 0.74-0.82) at 9.1 m. Sprint times and strength per body mass were significantly lower in lineman compared with linebackers-tight ends and backs. The acceleration and velocity patterns were the same for each position group, and differences in sprint time were determined by the magnitude of acceleration and velocity at 9.1 and 18.3 m. Sprint performance in football players is determined by a rapid increase in acceleration (through 18.3 m) and a high velocity maintained throughout the sprint and is independent of position played. The best sprint performances (independent of sprint distance) appear to be related to the highest initial acceleration (through 18.3 m) and highest attained and maintained velocity. Strength relative to body mass and power appears to

  20. Breed-specific ancestry studies and genome-wide association analysis highlight an association between the MYH9 gene and heat tolerance in Alaskan sprint racing sled dogs.

    PubMed

    Huson, Heather J; vonHoldt, Bridgett M; Rimbault, Maud; Byers, Alexandra M; Runstadler, Jonathan A; Parker, Heidi G; Ostrander, Elaine A

    2012-02-01

    Alaskan sled dogs are a genetically distinct population shaped by generations of selective interbreeding with purebred dogs to create a group of high-performance athletes. As a result of selective breeding strategies, sled dogs present a unique opportunity to employ admixture-mapping techniques to investigate how breed composition and trait selection impact genomic structure. We used admixture mapping to investigate genetic ancestry across the genomes of two classes of sled dogs, sprint and long-distance racers, and combined that with genome-wide association studies (GWAS) to identify regions that correlate with performance-enhancing traits. The sled dog genome is enhanced by differential contributions from four non-admixed breeds (Alaskan Malamute, Siberian Husky, German Shorthaired Pointer, and Borzoi). A principal components analysis (PCA) of 115,000 genome-wide SNPs clearly resolved the sprint and distance populations as distinct genetic groups, with longer blocks of linkage disequilibrium (LD) observed in the distance versus sprint dogs (7.5-10 and 2.5-3.75 kb, respectively). Furthermore, we identified eight regions with the genomic signal from either a selective sweep or an association analysis, corroborated by an excess of ancestry when comparing sprint and distance dogs. A comparison of elite and poor-performing sled dogs identified a single region significantly associated with heat tolerance. Within the region we identified seven SNPs within the myosin heavy chain 9 gene (MYH9) that were significantly associated with heat tolerance in sprint dogs, two of which correspond to conserved promoter and enhancer regions in the human ortholog.

  1. Effect of different warm-up procedures on subsequent swim and overall sprint distance triathlon performance.

    PubMed

    Binnie, Martyn J; Landers, Grant; Peeling, Peter

    2012-09-01

    This study investigated the effect of 3 warm-up procedures on subsequent swimming and overall triathlon performance. Seven moderately trained, amateur triathletes completed 4 separate testing sessions comprising 1 swimming time trial (STT) and 3 sprint distance triathlons (SDT). Before each SDT, the athletes completed 1 of three 10-minute warm-up protocols including (a) a swim-only warm-up (SWU), (b) a run-swim warm-up (RSWU), and (c) a control trial of no warm-up (NWU). Each subsequent SDT included a 750-m swim, a 500-kJ (∼20 km) ergometer cycle and a 5-km treadmill run, which the athletes performed at their perceived race intensity. Blood lactate, ratings of perceived exertion, core temperature, and heart rate were recorded over the course of each SDT, along with the measurement of swim speed, swim stroke rate, and swim stroke length. There were no significant differences in individual discipline split times or overall triathlon times between the NWU, SWU, and RSWU trials (p > 0.05). Furthermore, no difference existed between trials for any of the swimming variables measured (p > 0.05) nor did they significantly differ from the preliminary STT (p > 0.05). The findings of this study suggest that warming up before an SDT provides no additional benefit to subsequent swimming or overall triathlon performance.

  2. Sport Opportunities for Athletes with Disabilities.

    ERIC Educational Resources Information Center

    Journal of Physical Education, Recreation & Dance, 1984

    1984-01-01

    This series outlines sport opportunities for athletes with disabilities. Included are articles discussing sports for athletes with cerebral palsy, deaf athletes, blind athletes, wheelchair bound athletes, amputee athletes, as well as a discussion of the Special Olympics. (JMK)

  3. Bibliography on Collegiate Athletics.

    ERIC Educational Resources Information Center

    Francois, Denise; And Others

    1979-01-01

    A bibliography on collegiate athletics with approximately 400 items is presented. Topics include: sports administration, sports histories, women's athletics, physical education, problems and scandals, sports organizations, sports and health, and references on many specific sports, especially football. (JMD)

  4. Feeding Your Child Athlete

    MedlinePlus

    ... snacks. The child athlete, however, will have higher energy and fluid requirements. Kids and teens who are ... consume more food to keep up with increased energy demands. Most athletes will naturally eat the right ...

  5. Athlete's Foot (Tinea Pedis)

    MedlinePlus

    ... The most common locations for athlete's foot include: Spaces (webs) between the toes, especially between the 4th ... no worm involved.) Between the toes (the interdigital spaces), athlete's foot may appear as inflamed, scaly, and ...

  6. Variation in Football Players’ Sprint Test Performance Across Different Ages and Levels of Competition

    PubMed Central

    Abrantes, Catarina; Maçãs, Vitor; Sampaio, Jaime

    2004-01-01

    The purpose of this study was to compare sprint test performance performed by football players of different ages and levels of competition. One hundred and forty six Portuguese players from different teams completed the test (seven maximal sprints interspersed with 25 s active recovery). A 6 (level of competition: 1st national division, 2nd national division, 1st regional division, sub 16, sub 14, sub 12) 7 (sprint trial: sprint 1, sprint 2, sprint 3, sprint 4, sprint 5, sprint 6, sprint 7) repeated measures ANOVA was carried out on subjects sprint times. The main effect of level of competition was statistically significant, F(5, 140) = 106.28, p < 0.001. Subjects from 1st national division were significantly faster than subjects from 2nd national division; subjects from 1st regional division obtained similar performances when compared to sub 16 and sub 14 level; subjects from sub 12 level were the slowest. The main effect of sprint trial was also statistically significant, F (6, 840) = 7.37, p < 0.001. Mean sprint times from the first trial were significantly slower than mean sprint times from the second, third and fourth trial. Results from the fifth, sixth and seventh trials were slower, denoting a decrement in performance. The two main effects were qualified by a significant level of competition x sprint trial interaction, F (30, 840) = 9.47 p < 0.001, identifying markedly different performance profiles. Coaches should be aware that normative data regarding this test can play a very important role if used frequently and consistently during the whole season. Key Points Groups of different ages (Sub 16, Sub 14 and Sub 12) and groups of different training quality (1st and 2nd national divisions and 1st regional division) were clearly discriminated by sprint test performances. Professional players exhibited higher performances in sprint test. Fatigue effects were the strongest between 5th to the 7th sprint. PMID:24778553

  7. Athletic Identity, Vocational Identity, and Occupational Engagement in College Student-Athletes and Non-Athletes

    ERIC Educational Resources Information Center

    Hook, Lacole L.

    2012-01-01

    Athletic departments in National Collegiate Athletic Association Football Bowl Subdivision universities provide academic support services to their student-athletes. Even though student-athletes receive help including career assistance from academic counselors, some studies have found that student-athletes are behind non-athletes in career…

  8. Innovative camera system developed for Sprint vehicle

    SciTech Connect

    Not Available

    1985-04-01

    A new inspection system for the Sprint 101 ROV eliminates parallax errors because all three camera modules use a single lens for viewing. Parallax is the apparent displacement of an object when it is viewed from two points not in the same line of sight. The central camera is a Pentax 35-mm single lens reflex with a 28-mm lens. It comes with 250-shot film cassettes, an automatic film wind-on, and a data chamber display. An optical transfer assembly on the stills camera viewfinder transmits the image to one of the two video camera modules. The video picture transmitted to the surface is exactly the same as the stills photo. The surface operator can adjust the focus by viewing the video display.

  9. Giving students the run of sprinting models

    NASA Astrophysics Data System (ADS)

    Heck, André; Ellermeijer, Ton

    2009-11-01

    A biomechanical study of sprinting is an interesting task for students who have a background in mechanics and calculus. These students can work with real data and do practical investigations similar to the way sports scientists do research. Student research activities are viable when the students are familiar with tools to collect and work with data from sensors and video recordings and with modeling tools for comparing simulation and experimental results. This article describes a multipurpose system, named COACH, that offers a versatile integrated set of tools for learning, doing, and teaching mathematics and science in a computer-based inquiry approach. Automated tracking of reference points and correction of perspective distortion in videos, state-of-the-art algorithms for data smoothing and numerical differentiation, and graphical system dynamics based modeling are some of the built-in techniques that are suitable for motion analysis. Their implementation and their application in student activities involving models of running are discussed.

  10. Effect of pre-cooling on repeat-sprint performance in seasonally acclimatised males during an outdoor simulated team-sport protocol in warm conditions.

    PubMed

    Brade, Carly J; Dawson, Brian T; Wallman, Karen E

    2013-01-01

    Whether precooling is beneficial for exercise performance in warm climates when heat acclimatised is unclear. The purpose of this study was to determine the effect of precooling on repeat-sprint performance during a simulated team-sport circuit performed outdoors in warm, dry field conditions in seasonally acclimatised males (n = 10). They performed two trials, one with precooling (PC; ice slushy and cooling jacket) and another without (CONT). Trials began with a 30-min baseline/cooling period followed by an 80 min repeat-sprint protocol, comprising 4 x 20-min quarters, with 2 x 5-min quarter breaks and a 10-min half-time recovery/cooling period. A clear and substantial (negative; PC slower) effect was recorded for first quarter circuit time. Clear and trivial effects were recorded for overall circuit time, third and fourth quarter sprint times and fourth quarter best sprint time, otherwise unclear and trivial effects were recorded for remaining performance variables. Core temperature was moderately lower (Cohen's d=0.67; 90% CL=-1.27, 0.23) in PC at the end of the precooling period and quarter 1. No differences were found for mean skin temperature, heart rate, thermal sensation, or rating of perceived exertion, however, moderate Cohen's d effect sizes suggested a greater sweat loss in PC compared with CONT. In conclusion, repeat- sprint performance was neither clearly nor substantially improved in seasonally acclimatised players by using a combination of internal and external cooling methods prior to and during exercise performed in the field in warm, dry conditions. Of practical importance, precooling appears unnecessary for repeat-sprint performance if athletes are seasonally acclimatised or artificially acclimated to heat, as it provides no additional benefit. Key PointsPre-cooling did not improve repeated sprint performance during a prolonged team-sport circuit in field conditions.If individuals are already heat acclimatised/acclimated, pre-cooling is

  11. Detecting growth hormone misuse in athletes.

    PubMed

    Holt, Richard I G

    2013-10-01

    Athletes have been misusing growth hormone (GH) for its anabolic and metabolic effects since the early 1980s, at least a decade before endocrinologists began to treat adults with GH deficiency. Although there is an ongoing debate about whether GH is performance enhancing, recent studies suggest that GH improves strength and sprint capacity, particularly when combined with anabolic steroids. The detection of GH misuse is challenging because it is an endogenous hormone. Two approaches have been developed to detect GH misuse; the first is based on the measurement of pituitary GH isoforms and the ratio of 22-kDa isoform to total GH. The second is based on the measurement of insulin like growth factor-I (IGF-I) and N-terminal propeptide of type III procollagen (P-III-NP) which increase in a dose-dependent manner in response to GH administration. Both methodologies have been approved by the World Anti-Doping Agency (WADA) and have led to the detection of a number of athletes misusing GH.

  12. The Foundation of Athletics

    ERIC Educational Resources Information Center

    Curry, Tom

    2012-01-01

    As a coach, this author likes to share some thoughts on children and sports. After 42 years in athletics in all capacities--coach, athletic director, official, parent, athlete, and observer--he can easily say he has seen, heard, or experienced it all. Each experience has helped him gain some insights on youth and interscholastic sports. Parent of…

  13. Who Are Student Athletes?

    ERIC Educational Resources Information Center

    Watt, Sherry K.; Moore, James L., III

    2001-01-01

    Describes and discusses student athletes' experiences and their environments from historical and current perspectives. Provides recommendations for student affairs professionals who wish to assist student athletes in reducing the tension between the students' academic and athletic worlds. (Contains 38 references.) (GCP)

  14. Women in Athletic Leadership

    ERIC Educational Resources Information Center

    Moore, Sandra L.; Gilmour, Suzanne L.; Kinsella, Mary P.

    2005-01-01

    Despite significant increased participation opportunities for girls and women in sport following the passage of Title IX, women remain underrepresented in athletic leadership roles. Thirty eight female and 158 male high school athletic directors responded to a 19-item Athletic Director Survey (ADS) designed to elicit information on the following:…

  15. The Student Athlete Experience

    ERIC Educational Resources Information Center

    Gayles, Joy Gaston

    2009-01-01

    Prior to the 1980s, the literature on the experiences of collegiate student athletes was rather scarce. Since that time the National Collegiate Athletic Association (NCAA) has passed several eligibility rules to address concerns about the academic performance and the overall experience of student athletes on college campuses. As such, the…

  16. Blitzing Athletic Abuses.

    ERIC Educational Resources Information Center

    Greene, John B.

    1982-01-01

    Considers academic integrity in community college athletics as essential for student success. Discusses the ramifications of several athletics regulations in California, e.g., those related to athlete recruitment, transfer regulations, credit load requirements, and coach selection. Uses Merritt College's program as an example of a balanced…

  17. Effects of limited peripheral vision on shuttle sprint performance of soccer players.

    PubMed

    Lemmink, Koen A P M; Dijkstra, Baukje; Visscher, Chris

    2005-02-01

    This study examined the effect of limited peripheral vision on the shuttle sprint performance of soccer players. Participants were 14 male soccer players of a student soccer club (M age = 22.1 yr., SD = 1.3 yr.). They performed a repeated shuttle sprint with full and limited peripheral vision. Mean total sprint time and mean turning time increased significantly with limited peripheral vision. It is concluded that only turning during shuttle sprint performance decreases when sprinting with a restricted peripheral field of view, indicating the use of peripheral vision for the control of directional changes while sprinting.

  18. Hand Grip Strength Vs. Sprint Effectiveness in Amputee Soccer Players

    PubMed Central

    Wieczorek, Marta; Wiliński, Wojciech; Struzik, Artur; Rokita, Andrzej

    2015-01-01

    Amputee soccer is one of the types of soccer designed for the disabled, especially those who have undergone amputations, as well as those with extremity dysfunction. The objective of the study was to find the relationship between hand grip strength and sprint time in amputee soccer players. Thirteen field amputee soccer players participated in the study. A SAEHAN hydraulic hand dynamometer manufactured by Jamar was used for hand grip strength measurements. The sprint running test was conducted over a distance of 30 m. The Fusion Smart Speed System was employed for running time measurements. No statistically significant relationships were found between hand grip strength of the left or right hand, and sprint times over 1, 5, 10, 15, 20, 25 and 30 m. Analysis of the running velocity curve of the subjects showed an interesting profile characterized by a 15 meter-long acceleration phase and a significant velocity increase over a distance of 20 – 25 m. The study suggests that there is no relationship between hand grip strength and sprint effectiveness in amputee soccer players. The specificity of locomotion with the use of elbow crutches among elite Polish amputee soccer players probably accounts for the profile of the sprint velocity curve. Extension of the acceleration phase in the sprint run and a velocity increase in the subsequent part of the run were observed. PMID:26834881

  19. Hand Grip Strength Vs. Sprint Effectiveness in Amputee Soccer Players.

    PubMed

    Wieczorek, Marta; Wiliński, Wojciech; Struzik, Artur; Rokita, Andrzej

    2015-11-22

    Amputee soccer is one of the types of soccer designed for the disabled, especially those who have undergone amputations, as well as those with extremity dysfunction. The objective of the study was to find the relationship between hand grip strength and sprint time in amputee soccer players. Thirteen field amputee soccer players participated in the study. A SAEHAN hydraulic hand dynamometer manufactured by Jamar was used for hand grip strength measurements. The sprint running test was conducted over a distance of 30 m. The Fusion Smart Speed System was employed for running time measurements. No statistically significant relationships were found between hand grip strength of the left or right hand, and sprint times over 1, 5, 10, 15, 20, 25 and 30 m. Analysis of the running velocity curve of the subjects showed an interesting profile characterized by a 15 meter-long acceleration phase and a significant velocity increase over a distance of 20 - 25 m. The study suggests that there is no relationship between hand grip strength and sprint effectiveness in amputee soccer players. The specificity of locomotion with the use of elbow crutches among elite Polish amputee soccer players probably accounts for the profile of the sprint velocity curve. Extension of the acceleration phase in the sprint run and a velocity increase in the subsequent part of the run were observed.

  20. Biomechanical analysis of two standing sprint start techniques.

    PubMed

    LeDune, Jason A; Nesser, Thomas W; Finch, Alfred; Zakrajsek, Rebecca A

    2012-12-01

    The purpose of this study was to examine any differences between the false step standing sprint start and a traditional forward step standing sprint start. Ten DI collegiate female soccer players performed 2 standing sprint starts (Forward step and False step). Each player was videotaped for the first 3 steps of each sprint start. Velocity, acceleration, and displacement were calculated at each of the 3 steps for both standing sprint start techniques. Velocity was significantly faster with the forward step for steps 1 and 2 but not with step 3. Displacement was significantly greater with the forward step for each of the 3 steps. Acceleration was greater with the false step for each step though differences were not significant. The results indicate the forward step outperforms the false step in both velocity and displacement. Even though the false step generates greater acceleration, the backward step drastically undercuts displacement nullifying acceleration. Controversy exists between these 2 standing sprint starts with proponents arguing for their favorite with no evidence to suggest one or the other. The results from this study suggest that the forward step is superior to the false step when the concern for an individual is to get from 1 point to the next as fast as possible.

  1. Hand Grip Strength Vs. Sprint Effectiveness in Amputee Soccer Players.

    PubMed

    Wieczorek, Marta; Wiliński, Wojciech; Struzik, Artur; Rokita, Andrzej

    2015-11-22

    Amputee soccer is one of the types of soccer designed for the disabled, especially those who have undergone amputations, as well as those with extremity dysfunction. The objective of the study was to find the relationship between hand grip strength and sprint time in amputee soccer players. Thirteen field amputee soccer players participated in the study. A SAEHAN hydraulic hand dynamometer manufactured by Jamar was used for hand grip strength measurements. The sprint running test was conducted over a distance of 30 m. The Fusion Smart Speed System was employed for running time measurements. No statistically significant relationships were found between hand grip strength of the left or right hand, and sprint times over 1, 5, 10, 15, 20, 25 and 30 m. Analysis of the running velocity curve of the subjects showed an interesting profile characterized by a 15 meter-long acceleration phase and a significant velocity increase over a distance of 20 - 25 m. The study suggests that there is no relationship between hand grip strength and sprint effectiveness in amputee soccer players. The specificity of locomotion with the use of elbow crutches among elite Polish amputee soccer players probably accounts for the profile of the sprint velocity curve. Extension of the acceleration phase in the sprint run and a velocity increase in the subsequent part of the run were observed. PMID:26834881

  2. Bone health in endurance athletes: runners, cyclists, and swimmers.

    PubMed

    Scofield, Kirk L; Hecht, Suzanne

    2012-01-01

    Weight-bearing exercise has been recognized widely to be beneficial for long-term bone health. However inherent differences in bone-loading characteristics and energy expenditure during participation in endurance sports place many endurance athletes at a relative disadvantage with regard to bone health compared with other athletes. Adolescents and adults who participate in endurance sports, such as running, and non-weight-bearing sports, such as biking and swimming, often have lower bone mineral density (BMD) than athletes participating in ball and power sports, and sometimes their BMD is lower than their inactive peers. Low BMD increases the risk of stress and fragility fractures, both while an athlete is actively competing and later in life. This article reviews the variable effects of distance running, cycling, swimming, and triathlons on bone health; the evaluation of stress and fragility fractures; and the diagnosis, management, and prevention of low BMD in endurance athletes. PMID:23147022

  3. Bone health in endurance athletes: runners, cyclists, and swimmers.

    PubMed

    Scofield, Kirk L; Hecht, Suzanne

    2012-01-01

    Weight-bearing exercise has been recognized widely to be beneficial for long-term bone health. However inherent differences in bone-loading characteristics and energy expenditure during participation in endurance sports place many endurance athletes at a relative disadvantage with regard to bone health compared with other athletes. Adolescents and adults who participate in endurance sports, such as running, and non-weight-bearing sports, such as biking and swimming, often have lower bone mineral density (BMD) than athletes participating in ball and power sports, and sometimes their BMD is lower than their inactive peers. Low BMD increases the risk of stress and fragility fractures, both while an athlete is actively competing and later in life. This article reviews the variable effects of distance running, cycling, swimming, and triathlons on bone health; the evaluation of stress and fragility fractures; and the diagnosis, management, and prevention of low BMD in endurance athletes.

  4. Doppler ultrasound and tibial tuberosity maturation status predicts pain in adolescent male athletes with Osgood-Schlatter's disease: a case series with comparison group and clinical interpretation

    PubMed Central

    Sailly, Matthieu; Whiteley, Rod; Johnson, Amanda

    2013-01-01

    Background The pathogenesis of the Osgood-Schlatter's disease (OSD) is still debated. The fragmentation of the ossification centre has been questioned as a definitive sign of OSD and has been seen as a normal development of the anterior tibial tubercle (ATT). Objectives It is unknown if such changes are present in the presumed pathological tendon insertion seen in OSD, nor the relation of Doppler-positive changes to pain on clinical examination. Methods A prospective analysis was carried out on 20 consecutive symptomatic male athletes (13.9 years±1.3) and a comparison group of asymptomatic subjects. All underwent a comparative clinical assessment and ultrasound with colour Doppler scan on both knees. Subjective pain was recorded with a visual analogue scale (VAS) during provocative manoeuvres: palpation, resisted contraction and single leg squat. Results Positive Doppler US (within the distal end of the patellar tendon) was associated with higher pain on palpation (47±24.5 vs 18±11.4, p<0.01) and resisted static contraction (59±20.2 vs 27±12.5, p<0.001) compared with Doppler-negative subjects. No Doppler activity was found in the comparison group. VAS for palpation and resisted contraction of the athletes graded as stage 2 (51.1±22.0 and 60.0±21.2) were significantly higher than stage 3 (17.8±12.0 and 18.9±16.9) and stage 4 (15.0±7.1 and 25.0±7.1; p<0.01). Conclusions More painful OSD is associated with the presence of neo-vessels. This may be linked with a particular stage of ATT maturation and applied compressive forces. A Doppler ultrasound scan adds practical information to develop the care plan of the patient. PMID:22952406

  5. Athletes with seizure disorders.

    PubMed

    Knowles, Byron Don; Pleacher, Michael D

    2012-01-01

    Individuals with seizure disorders have long been restricted from participation in certain sporting activities. Those with seizure disorders are more likely than their peers to have a sedentary lifestyle and to develop obesity. Regular participation in physical activity can improve both physical and psychosocial outcomes for persons with seizure disorders. Seizure activity often is reduced among those patients who regularly engage in aerobic activity. Recent literature indicates that the diagnosis of seizure disorders remains highly stigmatizing in the adolescent population. Persons with seizure disorders may be more accepted by peer groups if they are allowed to participate in sports and recreational activities. Persons with seizure disorders are encouraged to participate in regular aerobic activities. They may participate in team sports and contact or collision activities provided that they utilize appropriate protective equipment. There seems to be no increased risk of injury or increasing seizure activity as the result of such participation. Persons with seizure disorders still are discouraged from participating in scuba diving and skydiving. The benefits of participation in regular sporting activity far outweigh any risk to the athlete with a seizure disorder who chooses to participate in sports.

  6. Performance Enhancing Diets and the PRISE Protocol to Optimize Athletic Performance

    PubMed Central

    Arciero, Paul J.; Ward, Emery

    2015-01-01

    The training regimens of modern-day athletes have evolved from the sole emphasis on a single fitness component (e.g., endurance athlete or resistance/strength athlete) to an integrative, multimode approach encompassing all four of the major fitness components: resistance (R), interval sprints (I), stretching (S), and endurance (E) training. Athletes rarely, if ever, focus their training on only one mode of exercise but instead routinely engage in a multimode training program. In addition, timed-daily protein (P) intake has become a hallmark for all athletes. Recent studies, including from our laboratory, have validated the effectiveness of this multimode paradigm (RISE) and protein-feeding regimen, which we have collectively termed PRISE. Unfortunately, sports nutrition recommendations and guidelines have lagged behind the PRISE integrative nutrition and training model and therefore limit an athletes' ability to succeed. Thus, it is the purpose of this review to provide a clearly defined roadmap linking specific performance enhancing diets (PEDs) with each PRISE component to facilitate optimal nourishment and ultimately optimal athletic performance. PMID:25949823

  7. Update on the female athlete triad.

    PubMed

    Barrack, Michelle T; Ackerman, Kathryn E; Gibbs, Jenna C

    2013-06-01

    Updated prevalence estimates of all 3 components of the Female Athlete Triad, a syndrome characterized by low energy availability, functional hypothalamic amenorrhea, and osteoporosis, is low (0 %-16 %), however, estimates of 1 or 2 concurrent components approach 50 %-60 % among certain athlete groups. Recent research identifies components of the Triad among female adolescent athletes, particularly those participating in leanness sports, such as endurance running. This is alarming, as adolescents require adequate nutrition and normal hormone function to optimize bone mineral gains during this critical developmental period. Current literature highlights new assessments, such as measurements of bone microarchitecture and hormone levels to better evaluate bone strength and the hormonal and metabolic profile of athletes with and at risk for the Triad. Recent data also provides support for additional potential consequences of the Triad, such as endothelial dysfunction and related cardiovascular effects, stress fractures, and musculoskeletal injuries. Additional prospective research is needed to evaluate long-term indicators and consequences of the Triad and identify effective behavioral treatment strategies. PMID:23613226

  8. Effect of high-intensity intermittent cycling sprints on neuromuscular activity.

    PubMed

    Billaut, F; Basset, F A; Giacomoni, M; Lemaître, F; Tricot, V; Falgairette, G

    2006-01-01

    High-intensity intermittent sprints induce changes in metabolic and mechanical parameters. However, very few data are available about electrical manifestations of muscle fatigue following such sprints. In this study, quadriceps electromyographic (EMG) responses to repeated all-out exercise bouts of short duration were assessed from maximal voluntary isometric contractions (MVC) performed before and after sprints. Twelve men performed ten 6-s maximal cycling sprints, separated by 30-s rest. The MVC were performed pre-sprints ( pre), post-sprints ( post), and 5 min post-sprints ( post5). Values of root-mean-square (RMS) and median frequency (MF) of vastus lateralis (VL) and vastus medialis (VM) were recorded during each MVC. During sprints, PPO decreased significantly in sprints 8, 9, and 10, compared to sprint 1 (- 8 %, - 10 %, and - 11 %, respectively, p < 0.05). Significant decrements were found in MVC post (- 13 %, p < 0.05) and MVC post5 (- 10.5 %, p < 0.05) compared to MVC pre. The RMS value of VL muscle increased significantly after sprints (RMS pre vs. RMS post: + 15 %, p < 0.05). Values of MF decreased significantly in both VL and VM after sprints. In conclusion, our results indicate that the increase in quadriceps EMG amplitude following high-intensity intermittent short sprints was not sufficient to maintain the required force output. The concomitant decrease in frequency components would suggest a modification in the pattern of muscle fiber recruitment, and a decrease in conduction velocity of active fibers. PMID:16388438

  9. Enzyme adaptations of human skeletal muscle during bicycle short-sprint training and detraining.

    PubMed

    Linossier, M T; Dormois, D; Perier, C; Frey, J; Geyssant, A; Denis, C

    1997-12-01

    The effect of sprint training and detraining on supramaximal performances was studied in relation to muscle enzyme adaptations in eight students trained four times a week for 9 weeks on a cycle ergometer. The subjects were tested for peak oxygen uptake (VO2peak), maximal aerobic power (MAP) and maximal short-term power output (Wmax) before and after training and after 7 weeks of detraining. During these periods, biopsies were taken from vastus lateralis muscle for the determination of creatine kinase (CK), adenylate kinase (AK), glycogen phosphorylase (PHOS), hexokinase (HK), phosphofructokinase (PFK), lactate dehydrogenase (LDH) and its isozymes, 3-hydroxy-acyl-CoA dehydrogenase (HAD) and citrate synthase (CS) activities. Training induced large improvements in Wmax (28%) with slight increases (3%) in VO2peak (P < 0.10). This was associated with a greater glycolytic potential as shown by higher activities for PHOS (9%), PFK (17%) and LDH (31%) after training, without changes in CK and oxidative markers (CS and HAD). Detraining induced significant decreases in VO2peak (4%), MAP (5%) and oxidative markers (10-16%), while Wmax and the anaerobic potential were maintained at a high level. This suggests a high level in supramaximal power output as a result of a muscle glycogenolytic and glycolytic adaptation. A long interruption in training has negligible effects on short-sprint ability and muscle anaerobic potential. On the other hand, a persistent training stimulus is required to maintain high aerobic capacity and muscle oxidative potential. This may contribute to a rapid return to competitive fitness for sprinters and power athletes.

  10. Muscle Oxygen Changes following Sprint Interval Cycling Training in Elite Field Hockey Players

    PubMed Central

    Jones, Ben; Hamilton, David K.; Cooper, Chris E.

    2015-01-01

    This study examined the effects of Sprint Interval Cycling (SIT) on muscle oxygenation kinetics and performance during the 30-15 intermittent fitness test (IFT). Twenty-five women hockey players of Olympic standard were randomly selected into an experimental group (EXP) and a control group (CON). The EXP group performed six additional SIT sessions over six weeks in addition to their normal training program. To explore the potential training-induced change, EXP subjects additionally completed 5 x 30s maximal intensity cycle testing before and after training. During these tests near-infrared spectroscopy (NIRS) measured parameters; oxyhaemoglobin + oxymyoglobin (HbO2+ MbO2), tissue deoxyhaemoglobin + deoxymyoglobin (HHb+HMb), total tissue haemoglobin (tHb) and tissue oxygenation (TSI %) were taken. In the EXP group (5.34±0.14 to 5.50±0.14m.s-1) but not the CON group (pre = 5.37±0.27 to 5.39±0.30m.s-1) significant changes were seen in the 30-15IFT performance. EXP group also displayed significant post-training increases during the sprint cycling: ΔTSI (−7.59±0.91 to −12.16±2.70%); ΔHHb+HMb (35.68±6.67 to 69.44±26.48μM.cm); and ΔHbO2+ MbO2 (−74.29±13.82 to −109.36±22.61μM.cm). No significant differences were seen in ΔtHb (−45.81±15.23 to −42.93±16.24). NIRS is able to detect positive peripheral muscle oxygenation changes when used during a SIT protocol which has been shown to be an effective training modality within elite athletes. PMID:25807517

  11. Gender differences in the physiological responses and kinematic behaviour of elite sprint cross-country skiers.

    PubMed

    Sandbakk, Oyvind; Ettema, Gertjan; Leirdal, Stig; Holmberg, Hans-Christer

    2012-03-01

    Gender differences in performance by elite endurance athletes, including runners, track cyclists and speed skaters, have been shown to be approximately 12%. The present study was designed to examine gender differences in physiological responses and kinematics associated with sprint cross-country skiing. Eight male and eight female elite sprint cross-country skiers, matched for performance, carried out a submaximal test, a test of maximal aerobic capacity (VO(2max)) and a shorter test of maximal treadmill speed (V (max)) during treadmill roller skiing utilizing the G3 skating technique. The men attained 17% higher speeds during both the VO(2max) and the V (max) tests (P < 0.05 in both cases), differences that were reduced to 9% upon normalization for fat-free body mass. Furthermore, the men exhibited 14 and 7% higher VO(2max) relative to total and fat-free body mass, respectively (P < 0.05 in both cases). The gross efficiency was similar for both gender groups. At the same absolute speed, men employed 11% longer cycles at lower rates, and at peak speed, 21% longer cycle lengths (P < 0.05 in all cases). The current study documents approximately 5% larger gender differences in performance and VO(2max) than those reported for comparable endurance sports. These differences reflect primarily the higher VO(2max) and lower percentage of body fat in men, since no gender differences in the ability to convert metabolic rate into work rate and speed were observed. With regards to kinematics, the gender difference in performance was explained by cycle length, not by cycle rate.

  12. Charlie's Words: Supporting Gifted Male Athletes Using Athletes' Journals

    ERIC Educational Resources Information Center

    Kent, Richard

    2012-01-01

    A gifted student-athlete, Charlie Bloomfield is introduced to athlete's journals by his coaches at Burke Mountain Academy (Vermont), an elite American ski school. Used by Olympians and professionals alike, journals provide athletes with ways to organize and reflect on training and competitions. Athlete's journals help gifted male athletes address…

  13. Athletic coaches as violence prevention advocates.

    PubMed

    Jaime, Maria Catrina D; McCauley, Heather L; Tancredi, Daniel J; Nettiksimmons, Jasmine; Decker, Michele R; Silverman, Jay G; O'Connor, Brian; Stetkevich, Nicholas; Miller, Elizabeth

    2015-04-01

    Adolescent relationship abuse (ARA) is a significant public health problem. Coaching Boys Into Men (CBIM) is an evidence-based ARA prevention program that trains coaches to deliver violence prevention messages to male athletes. Assessing acceptability and impact of CBIM on coaches may inform prevention efforts that involve these important adults in health promotion among youth. As part of a two-armed cluster-randomized controlled trial of CBIM in 16 high schools in Northern California, coaches completed baseline and postseason surveys (n = 176) to assess their attitudes and confidence delivering the program. Coaches in the intervention arm also participated in interviews (n = 36) that explored program acceptability, feasibility, and impact. Relative to controls, intervention coaches showed increases in confidence intervening when witnessing abusive behaviors among their athletes, greater bystander intervention, and greater frequency of violence-related discussions with athletes and other coaches. Coaches reported the program was easy to implement and valuable for their athletes. Findings illustrate the value of exploring attitudinal and behavioral changes among ARA prevention implementers, and suggest that coaches can gain confidence and enact behaviors to discourage ARA among male athletes. Coaches found the program to be feasible and valuable, which suggests potential for long-term uptake and sustainability.

  14. Prevention of eating disorders in female athletes.

    PubMed

    Coelho, Gabriela Morgado de Oliveira; Gomes, Ainá Innocencio da Silva; Ribeiro, Beatriz Gonçalves; Soares, Eliane de Abreu

    2014-01-01

    Eating disorders are serious mental diseases that frequently appear in female athletes. They are abnormal eating behaviors that can be diagnosed only by strict criteria. Disordered eating, although also characterized as abnormal eating behavior, does not include all the criteria for diagnosing eating disorders and is therefore a way to recognize the problem in its early stages. It is important to identify factors to avoid clinical progression in this high-risk population. Therefore, the purpose of this review is to discuss critical information for the prevention of eating disorders in female athletes. This review discusses the major correlates for the development of an eating disorder. We also discuss which athletes are possibly at highest risk for eating disorders, including those from lean sports and female adolescent athletes. There is an urgent need for the demystification of myths surrounding body weight and performance in sports. This review includes studies that tested different prevention programs' effectiveness, and the majority showed positive results. Educational programs are the best method for primary prevention of eating disorders. For secondary prevention, early identification is essential and should be performed by preparticipation exams, the recognition of dietary markers, and the use of validated self-report questionnaires or clinical interviews. In addition, more randomized clinical trials are needed with athletes from multiple sports in order for the most reliable recommendations to be made and for some sporting regulations to be changed.

  15. Prevention of eating disorders in female athletes

    PubMed Central

    Coelho, Gabriela Morgado de Oliveira; Gomes, Ainá Innocencio da Silva; Ribeiro, Beatriz Gonçalves; Soares, Eliane de Abreu

    2014-01-01

    Eating disorders are serious mental diseases that frequently appear in female athletes. They are abnormal eating behaviors that can be diagnosed only by strict criteria. Disordered eating, although also characterized as abnormal eating behavior, does not include all the criteria for diagnosing eating disorders and is therefore a way to recognize the problem in its early stages. It is important to identify factors to avoid clinical progression in this high-risk population. Therefore, the purpose of this review is to discuss critical information for the prevention of eating disorders in female athletes. This review discusses the major correlates for the development of an eating disorder. We also discuss which athletes are possibly at highest risk for eating disorders, including those from lean sports and female adolescent athletes. There is an urgent need for the demystification of myths surrounding body weight and performance in sports. This review includes studies that tested different prevention programs’ effectiveness, and the majority showed positive results. Educational programs are the best method for primary prevention of eating disorders. For secondary prevention, early identification is essential and should be performed by preparticipation exams, the recognition of dietary markers, and the use of validated self-report questionnaires or clinical interviews. In addition, more randomized clinical trials are needed with athletes from multiple sports in order for the most reliable recommendations to be made and for some sporting regulations to be changed. PMID:24891817

  16. Attention Deficit Hyperactivity Disorder and Athletes

    PubMed Central

    White, Russell D.; Harris, George D.; Gibson, Margaret E.

    2014-01-01

    Context: Attention deficit hyperactivity disorder (ADHD) is common in the general population, and many individuals with this condition participate in sports activity at all competition levels. Evidence Acquisition: Related studies were selected through literature searches of PubMed, MEDLINE, and Cochrane databases for the years 1991 to 2011. Key search terms were ADD, ADHD, sports, athletes, athletics, guidelines, NCAA, WADA, IOC, college, concussion, diagnosis, management, treatment, evaluation, return-to-play, pharmacotherapy, adult, adolescent, student, screening, injury, risk, neuropsychiatry, TBI, traumatic brain injury, and epidemiology. Study Design: Literature review. Level of Evidence: Level 4. Results: ADHD usually has an early onset, with delayed diagnosis in some patients due to heterogeneous presentations. Suspected cases can be evaluated with available diagnostic tools and confirmed clinically. Athletes with ADHD may participate at all competition levels. Conclusion: Athletes with ADHD are able to participate at all competition levels by following published guidelines and requirements. Exercise benefits many athletes with ADHD. The relationship between ADHD and concussion syndromes is currently under investigation. PMID:24587866

  17. Developmental and Contextual Risks of Social Physique Anxiety among Female Athletes

    ERIC Educational Resources Information Center

    Gay, Jennifer L.; Monsma, Eva V.; Torres-McGehee, Toni M.

    2011-01-01

    In the present study, we examined developmental and contextual factors that may increase the odds of reporting higher social physique anxiety (SPA) among 404 adolescent athletes 11 to 16 years old. Findings showed older, later maturing athletes past peak height velocity and with greater body mass index (BMI) reported higher SPA. Individual…

  18. Correlates of child activity and television: The contribution of children's athletic identity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is evidence that athletic self-concept can be both an important outcome and/or a mediating variable for physical activity in children and adolescents. However much less is known about the relationship between sedentary behaviors, such as television with athletic self-concept. This study exam...

  19. Long-Term Effects of Athletics Meet on the Perceived Competence of Individuals with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Ninot, Gregory; Maiano, Christophe

    2007-01-01

    The purpose was to examine the effects of the type of athletic program (integrated versus segregated) and of the type of sport (basketball versus swimming) on two domains of perceived competence (athletic competence and social acceptance), and general self-worth. Participants were 48 adolescent females with intellectual disabilities (ID) divided…

  20. The effect of ice ingestion on female athletes performing intermittent exercise in hot conditions.

    PubMed

    Zimmermann, Matthew Robert; Landers, Grant Justin

    2015-01-01

    Studies have reported the benefits of pre-cooling prior to exercise in the heat for male athletes, but at this time no research has investigated female athletes. The aim of the following study was to test the effects of pre-cooling on female repeat sprint performance in hot, humid conditions; namely is ice ingestion effective in reducing core temperature (Tc) and does this reduced Tc lead to improved repeat sprint performance in female athletes? Nine female team sport athletes with mean age (21.0 ± 1.2 y), height (169.8 ± 4.1 cm) and body mass (62.3 ± 5.0 kg) participated in this study. Participants completed 72 min of an intermittent sprint protocol (ISP) consisting of 2 × 36 min halves in hot, humid conditions (33.1 ± 0.1 °C, 60.3 ± 1.5% RH) on a cycle ergometer. This was preceded by 30 min of either ice ingestion (ICE) or water consumption (CON) in a randomised order. At the end of the pre-cooling period, Tc significantly decreased following ICE (-0.7 ± 0.3 °C) compared to CON (-0.1 ± 0.2 °C; p = 0.001). Tc also remained lower in ICE compared to CON during the ISP (p = 0.001). Ratings of perceived thermal sensation were lower in ICE compared to CON (p = 0.032) at the beginning (p = 0.022) and mid-point (p = 0.035) of the second half. No differences in work, mean power, peak power, rating of perceived exertion, heart rate or sweat loss between conditions were recorded (p > 0.05). Ice ingestion significantly reduced female Tc prior to intermittent exercise in the heat and reduced thermal sensation; however, this did not coincide with improved performance.

  1. Combined inhalation of beta2 -agonists improves swim ergometer sprint performance but not high-intensity swim performance.

    PubMed

    Kalsen, A; Hostrup, M; Bangsbo, J; Backer, V

    2014-10-01

    There is a high prevalence of asthma and airway hyperresponsiveness (AHR) in elite athletes, which leads to a major use of beta2 -agonists. In a randomized double-blinded crossover study, we investigated the effects of combined inhalation of beta2 -agonists (salbutamol, formoterol, and salmeterol), in permitted doses within the World Anti-Doping Agency 2013 prohibited list, in elite swimmers with (AHR, n = 13) or without (non-AHR, n = 17) AHR. Maximal voluntary isometric contraction of m. quadriceps (MVC), sprint performance on a swim ergometer and performance in an exhaustive swim test at 110% of VO2max were determined. Venous plasma interleukin-6 (IL-6) and interleukin-8 (IL-8) were measured post-exercise. No improvement was observed in the exhaustive swim test, but swim ergometer sprint time was improved (P < 0.05) in both groups from 57 ± 1.7 to 56 ± 1.8 s in AHR and 58.3 ± 1 to 57.4 ± 1 s in non-AHR. MVC and post-exercise plasma IL-6 increased (P < 0.05) with beta2 -agonists in both groups, whereas IL-8 only increased in AHR. In summary, inhalation of beta2 -agonists, in permitted doses, did not improve swim performance in elite swimmers. However, swim ergometer sprint performance and MVC were increased, which should be considered when making future anti-doping regulations. PMID:23834392

  2. The effect of 8-week plyometric training on leg power, jump and sprint performance in female soccer players.

    PubMed

    Ozbar, Nurper; Ates, Seda; Agopyan, Ani

    2014-10-01

    The aim of this study was to determine the effect of 8-week plyometric training (PT) on the leg power and jump and sprint performance in female soccer players. Eighteen female soccer players from Women Second League (age = 18.2 ± 2.3 years, height = 161.3 ± 5.4 cm, body mass = 56.6 ± 7.2 kg) were randomly assigned to control (n = 9) and plyometric (n = 9) groups. Both groups continued together with regular technical and tactical soccer training for 4 days a week. Additionally, the plyometric group underwent PT for 8 weeks, 1 day per week, 60-minute session duration. During the 8-week period, the control group was hindered from any additional conditioning training. All players' jumps (triple hop, countermovement jump, and standing broad jump), running speed (20 m), and peak power were evaluated before and after 8 weeks. No significant difference was found between the groups at pretest variables (p > 0.05). Significant improvements were found in the posttest of both the groups (p ≤ 0.05), except for 20-m sprint test in the control group (p > 0.05). Triple hop distance, countermovement jump, standing broad jump, peak power, and 20-m sprint test values were all significantly improved in the plyometric group, compared with the control group (p ≤ 0.05). We concluded that short duration PT is an improved important component of athletic performance in female soccer players. The results indicate that safe, effective, and alternative PT can be useful to strength and conditioning coaches, especially during competition season where less time is available for training.

  3. Combined inhalation of beta2 -agonists improves swim ergometer sprint performance but not high-intensity swim performance.

    PubMed

    Kalsen, A; Hostrup, M; Bangsbo, J; Backer, V

    2014-10-01

    There is a high prevalence of asthma and airway hyperresponsiveness (AHR) in elite athletes, which leads to a major use of beta2 -agonists. In a randomized double-blinded crossover study, we investigated the effects of combined inhalation of beta2 -agonists (salbutamol, formoterol, and salmeterol), in permitted doses within the World Anti-Doping Agency 2013 prohibited list, in elite swimmers with (AHR, n = 13) or without (non-AHR, n = 17) AHR. Maximal voluntary isometric contraction of m. quadriceps (MVC), sprint performance on a swim ergometer and performance in an exhaustive swim test at 110% of VO2max were determined. Venous plasma interleukin-6 (IL-6) and interleukin-8 (IL-8) were measured post-exercise. No improvement was observed in the exhaustive swim test, but swim ergometer sprint time was improved (P < 0.05) in both groups from 57 ± 1.7 to 56 ± 1.8 s in AHR and 58.3 ± 1 to 57.4 ± 1 s in non-AHR. MVC and post-exercise plasma IL-6 increased (P < 0.05) with beta2 -agonists in both groups, whereas IL-8 only increased in AHR. In summary, inhalation of beta2 -agonists, in permitted doses, did not improve swim performance in elite swimmers. However, swim ergometer sprint performance and MVC were increased, which should be considered when making future anti-doping regulations.

  4. Prediction of kinematic and kinetic performance in a drop vertical jump with individual anthropometric factors in adolescent female athletes: implications for cadaveric investigations.

    PubMed

    Bates, Nathaniel A; Myer, Gregory D; Hewett, Timothy E

    2015-04-01

    Anterior cruciate ligament injuries are common, expensive to repair, and often debilitate athletic careers. Robotic manipulators have evaluated knee ligament biomechanics in cadaveric specimens, but face limitations such as accounting for variation in bony geometry between specimens that may influence dynamic motion pathways. This study examined individual anthropometric measures for significant linear relationships with in vivo kinematic and kinetic performance and determined their implications for robotic studies. Anthropometrics and 3D motion during a 31 cm drop vertical jump task were collected in high school female basketball players. Anthropometric measures demonstrated differential statistical significance in linear regression models relative to kinematic variables (p-range <0.01-0.95). However, none of the anthropometric relationships accounted for clinical variance or provided substantive univariate accuracy needed for clinical prediction algorithms (r(2) < 0.20). Mass and BMI demonstrated models that were significant (p < 0.05) and predictive (r(2) > 0.20) relative to peak flexion moment, peak adduction moment, flexion moment range, abduction moment range, and internal rotation moment range. The current findings indicate that anthropometric measures are less associated with kinematics than with kinetics. Relative to the robotic manipulation of cadaveric limbs, the results do not support the need to normalize kinematic rotations relative to specimen dimensions.

  5. The effect of weight loss by ketogenic diet on the body composition, performance-related physical fitness factors and cytokines of Taekwondo athletes.

    PubMed

    Rhyu, Hyun-Seung; Cho, Su-Youn

    2014-10-01

    The purpose of this study was to investigate the effects of the weight loss through 3 weeks of ketogenic diet on performance-related physical fitness and inflammatory cytokines in Taekwondo athletes. The subjects selected for this research were 20 Taekwondo athletes of the high schools who participated in a summer camp training program. The subjects were randomly assigned to 2 groups, 10 subjects to each group: the ketogenic diet (KD) group and the non-ketogenic diet (NKD) group. Body composition, performance-related physical fitness factors (2,000 m sprint, Wingate test, grip force, back muscle strength, sit-up, 100 m sprint, standing broad jump, single leg standing) and cytokines (Iinterleukin-6, Interferon-γ, tumor necrosis factor-α) were analyzed before and after 3weeks of ketogenic diet. No difference between the KD and NKD groups in weight, %body fat, BMI and fat free mass. However, the KD group, compared to the NKD group, finished 2,000 m sprint in less time after weight loss, and also felt less fatigue as measured by the Wingate test and showed less increase in tumor necrosis factor-α. This result suggests that KD diet can be helpful for weight category athletes, such as Taekwondo athletes, by improving aerobic capacity and fatigue resistance capacity, and also by exerting positive effect on inflammatory response.

  6. The effect of weight loss by ketogenic diet on the body composition, performance-related physical fitness factors and cytokines of Taekwondo athletes

    PubMed Central

    Rhyu, Hyun-seung; Cho, Su-Youn

    2014-01-01

    The purpose of this study was to investigate the effects of the weight loss through 3 weeks of ketogenic diet on performance-related physical fitness and inflammatory cytokines in Taekwondo athletes. The subjects selected for this research were 20 Taekwondo athletes of the high schools who participated in a summer camp training program. The subjects were randomly assigned to 2 groups, 10 subjects to each group: the ketogenic diet (KD) group and the non-ketogenic diet (NKD) group. Body composition, performance-related physical fitness factors (2,000 m sprint, Wingate test, grip force, back muscle strength, sit-up, 100 m sprint, standing broad jump, single leg standing) and cytokines (Iinterleukin-6, Interferon-γ, tumor necrosis factor-α) were analyzed before and after 3weeks of ketogenic diet. No difference between the KD and NKD groups in weight, %body fat, BMI and fat free mass. However, the KD group, compared to the NKD group, finished 2,000 m sprint in less time after weight loss, and also felt less fatigue as measured by the Wingate test and showed less increase in tumor necrosis factor-α. This result suggests that KD diet can be helpful for weight category athletes, such as Taekwondo athletes, by improving aerobic capacity and fatigue resistance capacity, and also by exerting positive effect on inflammatory response. PMID:25426472

  7. Long-term training-induced changes in sprinting speed and sprint momentum in elite rugby union players.

    PubMed

    Barr, Matthew J; Sheppard, Jeremy M; Gabbett, Tim J; Newton, Robert U

    2014-10-01

    Speed and sprint momentum are considered to be important physical qualities for rugby. The purpose of the study was to understand the development of these qualities in senior and junior international rugby players. In part 1 of the study, a group of senior (n = 38) and junior (n = 31) players were tested for speed over 40 m. Initial sprint velocity (ISV), maximal sprint velocity (MSV), initial sprint momentum (ISM), and maximal sprint momentum (MSM) were calculated using 10-m splits. In part 2 of the study, a group of junior (n = 12) and senior (n = 15) players were tracked over a 2-year period for body mass, ISV, MSV, ISM, and MSM. In part 1, senior backs and forwards were not found to have significantly greater ISV and MSV than junior players but were found to have greater ISM and MSM. Forwards were found to have significantly greater ISM and MSM than backs but significantly lower ISV and MSV than backs. In part 2, no significant differences were found over the 2 years between senior and junior players, but greater effect sizes for juniors were generally found when compared with seniors for improvements in ISV (d = 0.73 vs. 0.79), MSV (d = 1.09 vs. 0.68), ISM (d = 0.96 vs. 0.54), and MSM (d = 1.15 vs. 0.50). Sprint momentum is a key discriminator between senior and junior players, and large changes can be made by junior players as they transition into senior rugby. Speed appears to peak for players in their early 20s but sprint momentum appears to be more trainable.

  8. Effects of 12-Week Endurance Training at Natural Low Altitude on the Blood Redox Homeostasis of Professional Adolescent Athletes: A Quasi-Experimental Field Trial.

    PubMed

    Tong, Tomas K; Kong, Zhaowei; Lin, Hua; He, Yeheng; Lippi, Giuseppe; Shi, Qingde; Zhang, Haifeng; Nie, Jinlei

    2016-01-01

    This field study investigated the influences of exposure to natural low altitude on endurance training-induced alterations of redox homeostasis in professional adolescent runners undergoing 12-week off-season conditioning program at an altitude of 1700 m (Alt), by comparison with that of their counterparts completing the program at sea-level (SL). For age-, gender-, and Tanner-stage-matched comparison, 26 runners (n = 13 in each group) were selected and studied. Following the conditioning program, unaltered serum levels of thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (T-AOC), and superoxide dismutase accompanied with an increase in oxidized glutathione (GSSG) and decreases of xanthine oxidase, reduced glutathione (GSH), and GSH/GSSG ratio were observed in both Alt and SL groups. Serum glutathione peroxidase and catalase did not change in SL, whereas these enzymes, respectively, decreased and increased in Alt. Uric acid (UA) decreased in SL and increased in Alt. Moreover, the decreases in GSH and GSH/GSSG ratio in Alt were relatively lower compared to those in SL. Further, significant interindividual correlations were found between changes in catalase and TBARS, as well as between UA and T-AOC. These findings suggest that long-term training at natural low altitude is unlikely to cause retained oxidative stress in professional adolescent runners.

  9. Effects of 12-Week Endurance Training at Natural Low Altitude on the Blood Redox Homeostasis of Professional Adolescent Athletes: A Quasi-Experimental Field Trial

    PubMed Central

    Tong, Tomas K.; Kong, Zhaowei; Lin, Hua; He, Yeheng; Lippi, Giuseppe; Shi, Qingde; Zhang, Haifeng

    2016-01-01

    This field study investigated the influences of exposure to natural low altitude on endurance training-induced alterations of redox homeostasis in professional adolescent runners undergoing 12-week off-season conditioning program at an altitude of 1700 m (Alt), by comparison with that of their counterparts completing the program at sea-level (SL). For age-, gender-, and Tanner-stage-matched comparison, 26 runners (n = 13 in each group) were selected and studied. Following the conditioning program, unaltered serum levels of thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (T-AOC), and superoxide dismutase accompanied with an increase in oxidized glutathione (GSSG) and decreases of xanthine oxidase, reduced glutathione (GSH), and GSH/GSSG ratio were observed in both Alt and SL groups. Serum glutathione peroxidase and catalase did not change in SL, whereas these enzymes, respectively, decreased and increased in Alt. Uric acid (UA) decreased in SL and increased in Alt. Moreover, the decreases in GSH and GSH/GSSG ratio in Alt were relatively lower compared to those in SL. Further, significant interindividual correlations were found between changes in catalase and TBARS, as well as between UA and T-AOC. These findings suggest that long-term training at natural low altitude is unlikely to cause retained oxidative stress in professional adolescent runners. PMID:26783415

  10. Effects of 12-Week Endurance Training at Natural Low Altitude on the Blood Redox Homeostasis of Professional Adolescent Athletes: A Quasi-Experimental Field Trial.

    PubMed

    Tong, Tomas K; Kong, Zhaowei; Lin, Hua; He, Yeheng; Lippi, Giuseppe; Shi, Qingde; Zhang, Haifeng; Nie, Jinlei

    2016-01-01

    This field study investigated the influences of exposure to natural low altitude on endurance training-induced alterations of redox homeostasis in professional adolescent runners undergoing 12-week off-season conditioning program at an altitude of 1700 m (Alt), by comparison with that of their counterparts completing the program at sea-level (SL). For age-, gender-, and Tanner-stage-matched comparison, 26 runners (n = 13 in each group) were selected and studied. Following the conditioning program, unaltered serum levels of thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (T-AOC), and superoxide dismutase accompanied with an increase in oxidized glutathione (GSSG) and decreases of xanthine oxidase, reduced glutathione (GSH), and GSH/GSSG ratio were observed in both Alt and SL groups. Serum glutathione peroxidase and catalase did not change in SL, whereas these enzymes, respectively, decreased and increased in Alt. Uric acid (UA) decreased in SL and increased in Alt. Moreover, the decreases in GSH and GSH/GSSG ratio in Alt were relatively lower compared to those in SL. Further, significant interindividual correlations were found between changes in catalase and TBARS, as well as between UA and T-AOC. These findings suggest that long-term training at natural low altitude is unlikely to cause retained oxidative stress in professional adolescent runners. PMID:26783415

  11. The Effects of Muscular Fatigue on the Kinetics of Sprint Running.

    ERIC Educational Resources Information Center

    Sprague, Paul; Mann, Ralph V.

    1983-01-01

    To compare the kinematic and kinetic effects of fatigue on the biomechanics of sprint running, male subjects were filmed performing a short maximal exertion sprint and a long fatiguing sprint. Observable differences in the productive muscular activity of the better and the poorer sprinters occurred during the ground-phase of their strides.…

  12. Physiological responses to an acute bout of sprint interval cycling.

    PubMed

    Freese, Eric C; Gist, Nicholas H; Cureton, Kirk J

    2013-10-01

    Sprint interval training has been shown to improve skeletal muscle oxidative capacity, V[Combining Dot Above]O2max, and health outcomes. However, the acute physiological responses to 4-7 maximal effort intervals have not been determined. To determine the V[Combining Dot Above]O2, cardiorespiratory responses, and energy expenditure during an acute bout of sprint interval cycling (SIC), health, college-aged subjects, 6 men and 6 women, completed 2 SIC sessions with at least 7 days between trials. Sprint interval cycling was performed on a cycle ergometer and involved a 5-minute warm-up followed by four 30-second all-out sprints with 4-minute active recovery. Peak oxygen uptake (ml·kg·min) during the 4 sprints were 35.3 ± 8.2, 38.8 ± 10.1, 38.8 ± 10.6, and 36.8 ± 9.3, and peak heart rate (b·min) were 164 ± 17, 172 ± 10, 177 ± 12, and 175 ± 22. We conclude that an acute bout of SIC elicits submaximal V[Combining Dot Above]O2 and cardiorespiratory responses during each interval that are above 80% of estimated maximal values. Although the duration of exercise in SIC is very short, the high level of V[Combining Dot Above]O2 and cardiorespiratory responses are sufficient to potentially elicit adaptations to training associated with elevated aerobic energy demand.

  13. Sprint swimming performance of wild bull trout (Salvelinus confluentus)

    USGS Publications Warehouse

    Mesa, M.G.; Phelps, J.; Weiland, L.K.

    2008-01-01

    We conducted laboratory experiments to determine the sprint swimming performance of wild juvenile and adult bull trout Salvelinus confluentus. Sprint swimming speeds were estimated using high-speed digital video analysis. Thirty two bull trout were tested in sizes ranging from about 10 to 31 cm. Of these, 14 fish showed at least one motivated, vigorous sprint. When plotted as a function of time, velocity of fish increased rapidly with the relation linear or slightly curvilinear. Their maximum velocity, or Vmax, ranged from 1.3 to 2.3 m/s, was usually achieved within 0.8 to 1.0 s, and was independent of fish size. Distances covered during these sprints ranged from 1.4 to 2.4 m. Our estimates of the sprint swimming performance are the first reported for this species and may be useful for producing or modifying fish passage structures that allow safe and effective passage of fish without overly exhausting them. ?? 2008 by the Northwest Scientific Association. All rights reserved.

  14. Limitations to maximum sprinting speed imposed by muscle mechanical properties.

    PubMed

    Miller, Ross H; Umberger, Brian R; Caldwell, Graham E

    2012-04-01

    It has been suggested that the force-velocity relationship of skeletal muscle plays a critical limiting role in the maximum speed at which humans can sprint. However, this theory has not been tested directly, and it is possible that other muscle mechanical properties play limiting roles as well. In this study, forward dynamics simulations of human sprinting were generated using a 2D musculoskeletal model actuated by Hill muscle models. The initial simulation results compared favorably to kinetic, kinematic, and electromyographic data recorded from sprinting humans. Muscle mechanical properties were then removed in isolation to quantify their effect on maximum sprinting speed. Removal of the force-velocity, excitation-activation, and force-length relationships increased the maximum speed by 15, 8, and 4%, respectively. Removal of the series elastic force-extension relationship decreased the maximum speed by 26%. Each relationship affected both stride length and stride frequency except for the force-length relationship, which mainly affected stride length. Removal of all muscular properties entirely (optimized joint torques) increased speed (+22%) to a greater extent than the removal of any single contractile property. The results indicate that the force-velocity relationship is indeed the most important contractile property of muscle regarding limits to maximum sprinting speed, but that other muscular properties also play important roles. Interactions between the various muscular properties should be considered when explaining limits to maximal human performance.

  15. Current and Future Treatment of Hypertension in the SPRINT Era.

    PubMed

    Phillips, Robert A

    2015-01-01

    Based on the SPRINT trial, it is highly likely that new SPRINT-era guidelines will establish a blood pressure (BP) goal of < 130/80 mm Hg for those aged 50 or older who are at high risk for a cardiovascular event. In this group, SPRINT demonstrated that assignment to an intensive-treatment systolic BP (SBP) goal of < 120 mm Hg significantly reduced cardiovascular events and mortality compared to those assigned to a standard-treatment SPB goal of < 140 mm Hg. This review critically assesses current hypertension guidelines and presents predictions for SPRINT-era guidelines in the elderly, African Americans, and patients with uncomplicated essential hypertension, diabetes, chronic kidney disease, cardiovascular disease, and coronary artery disease. Specific attention is paid to BP goals and preferred pharmacological antihypertensive therapy in these populations, and an algorithm that incorporates the SPRINT trial results is presented. Inhibitors of the renin-angiotensin-aldosterone system as well as calcium channel blockers are universally accepted as first-line therapy in uncomplicated hypertension, but controversy exists over the role of thiazide diuretics and beta blockers. This review also discusses a physiologically and outcomes-based approach to combination therapy for treatment of hypertension.

  16. Repeated sprints, high-intensity interval training, small-sided games: theory and application to field sports.

    PubMed

    Hoffmann, James J; Reed, Jacob P; Leiting, Keith; Chiang, Chieh-Ying; Stone, Michael H

    2014-03-01

    Due to the broad spectrum of physical characteristics necessary for success in field sports, numerous training modalities have been used develop physical preparedness. Sports like rugby, basketball, lacrosse, and others require athletes to be not only strong and powerful but also aerobically fit and able to recover from high-intensity intermittent exercise. This provides coaches and sport scientists with a complex range of variables to consider when developing training programs. This can often lead to confusion and the misuse of training modalities, particularly in the development of aerobic and anaerobic conditioning. This review outlines the benefits and general adaptations to 3 commonly used and effective conditioning methods: high-intensity interval training, repeated-sprint training, and small-sided games. The goals and outcomes of these training methods are discussed, and practical implementations strategies for coaches and spor