Sprint Capacity Research Articles

Integrative Neuromuscular Training Enhances Physical Fitness in 6- to 14-Year-Old Rugby Players.

Alonso-Aubin, DA, Picón-Martínez, M, Rebullido, TR, Faigenbaum, AD, Cortell-Tormo, JM, and Chulvi-Medrano, I. Integrative neuromuscular training enhances physical fitness in 6- to 14-year-old rugby players. J Strength Cond Res 35(8): 2263-2271, 2021-The purpose of this study was to assess the effects of an 8-week integrative neuromuscular training (INT) program on physical fitness measures in young rugby players. A sample of 138 male rugby players (age range, 6-14 years) was divided into 5 age-related groups: group 1 (G1) (n = 20; age, 7.05 ± 0.58), group 2 (G2) (n = 27; age, 8.57 ± 0.49), group 3 (G3) (n = 31; age, 11.02 ± 0.56), group 4 (G4) (n = 33; age, 13.12 ± 0.58, and group 5 (G5) (n = 27; age, 14.85 ± 1.53 and additionally into 2 game position groups: forwards (FOR) (n = 69) and backs (BAC) (n = 69). Physical fitness measures included the Functional Movement Screen (FMS), dominant and nondominant hand-to-eye coordination, sprint capacity, core muscular endurance, and lower- and upper-body power. Integrative neuromuscular training (INT) included progressive strength, coordination, and speed exercises performed twice per week for 20 minutes. Following INT, significant improvements in selected age-related groups (p < 0.01) were found in total FMS score G3 (effect size [ES] = 0.47), G4 (ES = 0.88), and G5 (ES = 0.58); dominant hand-to-eye coordination G1 (ES = 1.48), G2 (ES = 0.71), G3 (ES = 0.55), G4 (ES = 1.47), and G5 (ES = 1.15), nondominant hand-to-eye coordination G2 (ES = 0.74), G4 (ES = 1.34), and G5 (ES = 1.09); lower-body power G2 (ES = 0.44), G4 (ES = 0.39), and G5 (ES = 0.43); core muscular endurance G1 (ES = 0.82), G3 (ES = 0.68), and G4 (ES = 1.04); upper-body power G2 (ES = 0.53); and sprint capacity G4 (ES = 0.69). Significant improvements were also found between player's positions for all tests. These findings indicate that a progressive INT program can enhance functional movement abilities and selected physical fitness measures in young rugby players regardless of game position and age.

Effects of Training on Sand or Hard Surfaces on Sprint and Jump Performance of Team-Sport Players: A Systematic Review With Meta-Analysis

ABSTRACT We examined the effectiveness of training on sand and compared the effects of sand and hard surface training programs on the sprint and jump performance of team-sport players. PubMed MEDLINE, SPORTDiscus, and Web of Science databases were used in the literature search. A total of 377 records were initially identified, and 6 studies comprising 136 athletes were included in the meta-analysis. Precomparisons and postcomparisons showed that sand training interventions were effective at improving both jump and sprint capacities. When comparing sand and hard surfaces, no significant differences in favor of any of the interventions were observed. In summary, this review revealed that sand training is an efficient strategy to improve jump and sprint performances in team-sport players. Moreover, sand surfaces produced similar gains to those observed after hard surface training schemes. Strength and conditioning coaches and sport scientists who work with team sports can use both sand and hard surface training programs as part of their regular training practices, during distinct phases of the season.

Fitness and Performance Testing of Male and Female Beach Soccer Players-A Preliminary Investigation.

Purpose: This study aimed to compare performance on sand and a firm surface and to describe the physical capacity of male and female beach soccer players.Methods: Sixty-six male and 29 female competitive beach soccer players voluntarily participated in this study. Firstly, within-subjects test scores were compared to scores on a firm surface (criterion validity; n = 15 men) and reconducted on a second occasion (reliability; n = 51 men). Secondly, the best score on sand was retained to compare test performance between ages (classified as below 20, 20–30, and above 30 years) and sexes. Performance assessments included sprint time over 5 and 15 m (once on a firm surface and twice on sand), standing long jump (SLJ, once on a firm surface and twice on sand) and Yo-Yo intermittent recovery level 1 (Yo-Yo IR1, once on a firm surface and once on sand; only data for men were available).Results: Five-m sprint and Yo-Yo IR1 performance on sand were not correlated to performance on a firm surface (P > 0.05). Test-retest reliability was acceptable for the 15-m sprint and SLJ tests (ICC > 0.90; CV < 5%). Performance in 15-m sprint and maximal sprinting speed were moderately lower in male players aged above 30 years. compared to players aged below 30 years (d = 0.35–0.42; P < 0.05). Irrespective of the age group, weight-bearing power-based performance mass was moderately to very largely higher in male players than in female players (d = 0.42–0.88; P < 0.05).Conclusions: The lack of a consistent relationship between performance on sand and on a firm surface might indicate the need to develop specific test batteries for sand-based athletes. Age-related differences in physical performance were evident only in sprint capacity. Further studies are warranted to elucidate our preliminary findings and to develop the sand specific tests.

Observations of Performance and Body Composition Following 8-weeks of Progressive Resistance Training in Participants With Cerebral Palsy

Purpose: To observe the effects of progressive resistance training on performance and body composition in participants with cerebral palsy. Methods: Four quadriplegic (3 male, 1 female) and two hemiplegic (2 female) participants (22 ± 5 yr, mean ± SD) completed moderate to high intensity resistance training 2-3 days a week for 8-weeks. Strength training programs were developed for each participant based on their physical ability. Measurements of exercise performance and body composition (InBody 270 &amp; S10) were collected prior to and following training. Data from all participants was pooled, and samples with 5-6 subjects were analyzed using a paired t-test with significance set at p &lt; 0.05. Results: Measurements of muscular fitness improved, including plank performance (pre: 64 ± 40, post: 95 ± 61 s, n = 6), supine sled leg press 1RM (pre: 225 ± 69, post: 378 ± 124 lb, n = 6) and bench/sled press 1RM (pre: 92 ± 54, post: 115 ± 58 lb, n = 5). There was no change in peak sprint capacity (pre: 89 ± 32, post: 96 ± 29 W, n = 5) or peak aerobic capacity (pre: 303 ± 136, post: 370 ± 246 s, n = 4). Measurements of body weight (pre: 151 ± 40, post: 151 ± 42 lb, n = 6) and skeletal muscle mass (pre: 53 ± 8, post: 54 ± 9 lb, n = 6) were unchanged following training. Conclusion: Preliminary data is encouraging that the unique and challenging strength training program employed with these participants can be utilized to gain meaningful improvements in muscular fitness. However, a larger sample size and longer training period may be necessary to significantly increase muscle mass.

Traditional Free-Weight Vs. Variable Resistance Training Applied to Elite Young Soccer Players During a Short Preseason: Effects on Strength, Speed, and Power Performance.

Loturco, I, Pereira, LA, Reis, VP, Zanetti, V, Bishop, C, and Mcguigan, MR. Traditional free-weight vs. variable resistance training applied to elite young soccer players during a short preseason: Effects on strength, speed, and power performance. J Strength Cond Res 36(12): 3432-3439, 2022-Maximizing the neuromuscular capacities of players is a critical challenge during short soccer preseasons. This study compared the effects of 2 strength-power training regimes, on the strength, speed, and power performance of elite young soccer players during a 4-week preseason. Twenty-five under-20 players from the same club were pair matched in 2 training groups as follows: traditional training group (TTG) ( n = 13), athletes performed half-squat (HS) and jump-squat (JS) exercises as traditionally prescribed, and elastic band (EB) group (EBG) ( n = 12), athletes performed HS and JS with EB attached to the barbell. Vertical jump height, 20-m sprint velocity, change of direction (COD) speed, HS and JS power, and 1 repetition maximum (1RM) in the HS were assessed before, after 2-week, and after 4-week of training. A two-way analysis of variance with repeated measures was used to assess the effects of both training protocols over the experimental period. Both strategies were effective for significantly improving HS and JS power (effect sizes [ESs] = 1.00-1.77), HS 1RM (ES = 1.68 and 1.51 for TTG and EBG, respectively), vertical jumping ability (ES = 0.37-0.65), and COD speed (ES = 0.81 and 0.39 for TTG and EBG, respectively), when comparing premeasures and postmeasures. By contrast, both TTG and EBG failed to increase 20-m sprint velocity (ES ranging between -0.54 and 0.23). In conclusion, both training schemes were able to improve the strength and power performance but not the sprint capacity of young soccer players. To accelerate strength gains over very-short time periods (i.e., 2 weeks), variable resistance training may be advantageous. Conversely, to optimize power adaptations in ballistic exercises across a similar time period, traditional free-weight training may be preferred.

Improvements in Muscle Strength Are Associated With Improvements in Walking Capacity in Young Children With Cerebral Palsy: A Secondary Analysis.

To evaluate whether changes in lower-limb muscle strength explain changes in walking capacity during 14-week periods of usual care, power training and follow-up for children with spastic cerebral palsy. Secondary analysis of a previously conducted double-baseline controlled trial of 22 children with spastic cerebral palsy. Generalized estimating equations were used to evaluate the relationships between within-subject changes in isometric muscle strength and walking capacity over 3 periods. Changes in hip abductor strength were associated with changes in the Muscle Power Sprint Test, changes in gastrocnemius and hip abductor strength were associated with changes in the Shuttle Run Test, and changes in gastrocnemius strength were associated with changes in the 1-minute walk test. All associations supported better walking capacity with increased strength. Walking capacity, especially sprint capacity, can be improved by increasing strength by functional power training in this population.

INVESTIGATION OF THE EFFECTS OF 8-WEEK FOOTBALL TRAINING ON FINE MOTOR SKILLS AND SELECTED PHYSICAL FITNESS ELEMENTS IN 11-13 YEARS OLD CHILDREN GROUP

This study aims to investigate the effects of 8-week football training on selected physical fitness elements and fine motor skills in 11-13-year-old children. Among the children who participated in the study, the children playing football in Marmarisspor formed the experimental group (n: 30), and the children studying at Salih Zeki Gur Secondary School formed the control group (n: 30). In total, 60 volunteer children participated in the study. The experimental method is applied in this study. Football training was applied to the participating group for 8 weeks, 3 days a week, and 50-60 minutes, and no exercise was applied to the control group. Statistical analysis of the data obtained from the research was done in the SPPS (version 16.0) package program. After examining the normality distribution of pre - test and post - test values of experiment and control groups with the Shapiro-Wilk test, paired t-test was used to compare the averages. The significance level was accepted as p 0, 05); there was a significant difference between body weight and flexibility features (p <0.05). It has been observed that 8-week football training positively affects body weight, body mass index, flexibility, handgrip strength, balance, fine motor skill, 30-meter sprint, and aerobic capacity (ml/kg/min). Article visualizations:

Greater Association of Relative Thresholds Than Absolute Thresholds With Noncontact Lower-Body Injury in Professional Australian Rules Footballers: Implications for Sprint Monitoring.

To examine the relationship between sprint workloads using relative versus absolute thresholds and lower-body soft-tissue and bone-stress injury incidence in professional Australian rules football. Fifty-three professional Australian rules football athletes' noncontact soft-tissue and bone-stress lower-body injuries (N = 62) were recorded, and sprint workloads were quantified over ∼18 months using the global positioning system. Sprint volume (m) and exposures (n) were determined using 2 methods: absolute (>24.9km·h-1) and relative (≥75%, ≥80%, ≥85%, ≥90%, ≥95% of maximal velocity). Relationships between threshold methods and injury incidence were assessed using logistic generalized additive models. Incidence rate ratios and model performances' area under the curve were reported. Mean (SD) maximal velocity for the group was 31.5 (1.4), range 28.6 to 34.9km·h-1. In comparing relative and absolute thresholds, 75% maximal velocity equated to ~1.5km·h-1 below the absolute speed threshold, while 80% and 85% maximal velocity were 0.1 and 1.7km·h-1 above the absolute speed threshold, respectively. Model area under the curve ranged from 0.48 to 0.61. Very low and very high cumulative sprint loads ≥80% across a 4-week period, when measured relatively, resulted in higher incidence rate ratios (2.54-3.29), than absolute thresholds (1.18-1.58). Monitoring sprinting volume relative to an athlete's maximal velocity should be incorporated into athlete monitoring systems. Specifically, quantifying the distance covered at >80% maximal velocity will ensure greater accuracy in determining sprint workloads and associated injury risk.

The influence of youth soccer players’ sprint performance on the different sided games’ external load using GPS devices

ABSTRACTThe aims of this study are 1) to compare sided games’ (SGs) external responses encountered by players according to pitch size and to 2) examine the relationships between sprint performance and SGs’ external physical responses. Twenty soccer players under 15 years of age (U-15) participated in this study. Each player performed a sprinting test (10 m and 30 m sprints) and played a SG on two different pitch sizes (small at 100 [SSG] and large at 200 [LSG] m2 per player). Higher external responses (p < 0.01, ES = −6.41–1.22) were found in LSG in comparison to SSG, except to distance accelerating and decelerating (p > 0.05, ES = −0.26–0.27). Players who were faster over 10 and 30 m covered higher distances cruising and sprinting (r = −0.47/-0.66; ± 0.23/± 0.30, respectively, p < 0.05), performed a greater number of sprints, achieved higher maximum velocity (Velmax) during LSG and covered a greater distance at high-intensity accelerating (r = −0.50/-0.70; ±0.21/±0.29, respectively, p < 0.05) during both SG. LSG demanded a higher external load in comparison with SSG. In addition, the improved sprint capacity could allow players to perform greater running activities and short-term actions at high-intensities during SG.

The Use and Abuse of Growth Hormone in Sports.

GH is banned by the World Anti-Doping Agency as a performance-enhancing anabolic agent. Doping with GH likely began in the early 1980s and became more prevalent with the advent of recombinant technology well before any scientific evidence of benefit. The expectation that GH improves physical function stems from its anabolic and lipolytic properties. Athletic performance depends on muscle strength and the energy required to power muscle function. In recreational athletes, GH selectively improves anaerobic sprint capacity but has not been proven to significantly enhance muscle strength, power, or maximum rate of oxygen consumption. GH is secreted as a family of isoform peptides in a pulsatile manner reflecting intermittent secretion and rapid clearance. Its anabolic actions are largely mediated by IGF-I, which stimulates whole-body protein synthesis, including skeletal muscle and collagen proteins. Two methods have been validated for detecting GH abuse in athletes. The first (the isoform method) is based on distinguishing pure recombinant 22-kDa GH from the heterogeneous isoforms secreted from the pituitary. The second (the marker method) is based on measuring blood levels of GH-responsive proteins, specifically IGF-I and the N-terminal propeptide of type III collagen (P-III-NP). Only a handful of athletes have been caught since the implementation of GH doping tests in 2004. The low rate likely reflects the limitation of in-competition testing using current methods. Improved detection rates may be achieved by more out-of-competition testing, introducing athletes' biological passports, and the development of novel methods. Governance, operational, technical, and political factors influence the effectiveness of an anti-doping program.

Initial Maximum Push-Rim Propulsion and Sprint Performance in Elite Wheelchair Rugby Players.

García-Fresneda, A, Carmona, G, Padullés, X, Nuell, S, Padullés, JM, Cadefau, JA, and Iturricastillo, A. Initial maximum push-rim propulsion and sprint performance in elite wheelchair rugby players. J Strength Cond Res 33(3): 857-865, 2019-Wheelchair rugby (WR) is an increasingly popular Paralympic sport; however, the evidence base supporting the validity and reliability of field tests to assess the physical condition of WR players is in its infancy. Therefore, here, we aimed to evaluate the intrasession reliability of the initial maximum push-rim propulsion (IMPRP) test and the sprint test, and to determine the relationships between IMPRP mechanical outputs and sprint performance variables. We studied 16 Spanish WR players (aged 33 ± 9 years). The maximum single wheelchair push from a stationary position and the sprint performance (i.e., times for 3, 5, and 12 m, and the maximum velocity) of elite WR players were measured in this study. The intraclass correlation coefficient, coefficient of variation, and standard error of measurement for IMPRP variables were >0.85, <10.6%, and <16.76, respectively; the corresponding values for a linear sprint were >0.97, <3.50%, and <0.15. In relation to IMPRP mechanical outputs (i.e., acceleration, maximum acceleration, force, maximum force, power, and maximum power) and sprint performance (i.e., times for 3, 5, and 12 m, and the maximum velocity), significant and large associations were observed in the WR players (r ± confidence limit = -0.78 ± 0.17 to -0.90 ± 0.11; 0/0/100, most likely; R = 0.613-0.812; p < 0.001). These tests provide simple and reliable methods for obtaining accurate mechanical pushing capacities and sprint performances of WR competitors (the 61.4-80.1% variance in sprint performance was explained by the IMPRP variables). These relationships indicate a need to implement specific strength exercises in WR players with the aim of improving the IMPRP and therefore improving sprint capacity.

Palaeoecological and genetic evidence for Neanderthal power locomotion as an adaptation to a woodland environment

The prevailing explanation for Neanderthal body form is the cold (glacial) adaptation hypothesis. However, palaeoecological associations appear to indicate a less cold woodland environment. Under such conditions, encounter and ambush (rather than pursuit) hunting – and thus muscular power and sprint (rather than endurance) capacity – would have been favoured. We hypothesise that the highly muscular Neanderthal body form reflects an adaptation to hunting conditions rather than cold, and here both review the palaeoecological evidence that they inhabited a mainly woodland environment, and present preliminary genetic analyses in support of this new hypothesis.

The use of dietary supplements among soccer referees: How much do they know?

Referees are essential for the correct execution of each soccer match and national soccer associations support them with physical training guidelines in order to improve agility, aerobic and sprint capacity, to reduce the risk of injury and to meet the minimum required performance levels. Despite the importance given to performance skills no specific nutritional guideline is provided to support the performance required. This study was aimed to investigate soccer field and assistant referees knowledge and consumption of dietary supplements. Seventy-one European referees participated to this survey by filling a short and quick anonymous questionnaire designed to collect information about their refereeing category, educational level, frequency of supplement consumption, type of supplement consumed. Moreover, a sub-group of 20 participants wore a training watch to record energy expenditure, distance, and heart rate during training sessions and matches. Our data show that referees frequently consume supplements especially those refereeing in lower categories, moreover they often follow a friend’s suggestion when deciding to take a supplement instead of trusting a professional prescription. According to our survey, national and international soccer federations should care more about their referee nutritional education.

Comparison of Agility, Sprint, Anaerobic Power and Aerobic Capacities of Soccer Players by Playing Positions

This study was carried out to compare the agility, sprint, anaerobic power and aerobic capacities of the soccer players by their playing positions. 33 male soccer players (defenders (n=8) 20±1.73 years; midfielders (n=10) 20.09±1.97 years forwards (n=7) 20.55±1.91) with a training age of over 5 years playing in different positions in Kastamonu amateur league participated in the study voluntarily. First, Body Mass Index (BMI) values were calculated by measuring the height and weight of each player. Then, Illinois Agility Test, Yoyo Intermittent Recovery Test, 30 m. Sprint Test and Running-Based Anaerobic Sprint Test (RAST) were conducted. Statistical analysis was done with the SPSS 22.0 program. No statistically significant differences were observed between defenders, midfielder and forwards in Yoyo Test (m.), MaxVO2 (ml/kg/min.), RAST maximal power, RAST average power and RAST fatigue index (p&gt;0.05). However, a significant difference was found between players in Illinois Test (sec.) and 30 m. Sprint Test (sec.) (p&lt;0.05). Forwards and midfielders were more agile than defenders, and midfielders were faster than defenders. It will therefore contribute to their performance to evaluate physical and physiological needs according to playing positions as the distances players cover vary depending on their playing positions (defense, midfield and forward) along with the movements they perform on the pitch and the frequency of these movements.

Effects of fatigue on interception decisions in soccer

In competitive soccer, match-induced fatigue is a common phenomenon that may negatively influence performance. Focusing on decision-making, the current study experimentally tested the impact of fatigue on players’ interception decisions and, in doing so, also took into account potential effects on physical capacity and motivation. Using a counterbalanced pretest–posttest design, 30 well-trained amateur soccer players were tested in a fatigued state vs. a non-fatigued control state (i.e. after performing a simulated soccer match and after watching soccer on television). Before and after both protocols, players performed a sprint test and an interception test in which they were instructed to either intercept or not intercept passes of different speeds. Dependent variables included physical capacity (i.e. maximal sprint capacity), motivation to intercept, decisions to intercept, and success rate of interceptions. Results showed that motivation to intercept but not sprint capacity was negatively affected by fatigue. Despite changes in motivation, fatigue did not significantly affect the number of interception attempts or the success rate of interceptions. In conclusion, findings suggest that match-induced fatigue reduces players’ self-reported motivation to engage in effortful actions (i.e. interception attempts) but does not necessarily affect objective (maximal) physical capacity and decision-making.

Determinant Factors of Physical Performance and Specific Throwing in Handball Players of Different Ages.

Ortega-Becerra, M, Pareja-Blanco, F, Jiménez-Reyes, P, Cuadrado-Peñafiel, V, and González-Badillo, JJ. Determinant factors of physical performance and specific throwing in handball players of different ages. J Strength Cond Res 32(6): 1778-1786, 2018-This study aimed to analyze various fitness qualities in handball players of different ages and to determine the relationships between these parameters and throwing velocity. A total of 44 handball players participated, pooled by age groups: professional (ELITE, n = 13); under-18 (U18, n = 16); under-16 (U16, n = 15). The following tests were completed: 20-m running sprints; countermovement jumps (CMJs); jump squat to determine the load that elicited ∼20 cm jump height (JSLOAD-20 cm); a progressive loading test in full squat and bench press to determine the load that elicited ∼1 m·s (SQ-V1-LOAD and BP-V1-LOAD); and handball throwing (jump throw and 3-step throw). ELITE showed greater performance in almost all sprint distances, CMJ, JSLOAD-20 cm, and bench press strength than U18 and U16. The differences between U18 and U16 were unclear for these variables. ELITE also showed greater (p < 0.001) performance for squat strength and throwing than U18 and U16, and U18 attained greater performance (p ≤ 0.05) for these variables than U16. Throwing performance correlated (p ≤ 0.05) with sprint times (r = -0.31; -0.51) and jump ability (CMJ: r = 0.39; 0.56 and JSLOAD-20 cm: r = 0.57; 0.60). Muscle strength was also associated (p < 0.001) with both types of throw (SQ-V1-LOAD: r = 0.66; 0.76; and BP-V1-LOAD: r = 0.33; 0.70). These results indicate that handball throwing velocity is strongly associated with lower-limb strength, although upper-limb strength, jumping and sprint capacities also play a relevant role in throwing performance, suggesting the need for coaches to include proper strength programs to improve handball players' throwing velocity.

Predictors of Initial Acceleration and Maximum Speed Phases of Sprint Running in Children and Adolescents

Sprint capacity is a key factor to succeed in many sports modalities and to identify successful predictors must be relevant to optimize speed training and talent detection. Jump tests, muscle strength, and anthropometric variables have been widely associated with sprint performance in adults. However, seeking the best sprinters among young individuals must be influenced by other variables such as sports training, body size, and maturation. Thus, the potential of jump and strength tests to explain sprinting phases (acceleration and maximum speed) might be affected during developmental ages. PURPOSE: To examine relations between the phases of sprinting performance (30m) and body composition (BC), maturation, strength, and jump tests in children and adolescents. METHODS: A database of 456 measures of participants aged 8-18y was analyzed (244 boys, age=14.8±2.3y, BMI=21.6±3.9kg/m2). Photoelectrical cells were used to measure sprint times (S30m, S0-15m, and S15-30m). An electronic mat read flight time to calculate vertical height after squat jump (SJ), counter-movement jump (CMJ), and CMJ with arms (CMJA); the difference between SJ and CMJ was also calculated (VJ- d). Lower limbs strength was tested with a portable dynamometer (LLS). Fat-free mass (FFM) was assessed by anthropometry and bioelectrical impedance analysis. Sports participation (SP) was recorded by questionnaire. A stepwise regression analysis was used to explore the relationship between sprint phases and BC, SP, jump and strength. RESULTS: CMJA was the best predictor of S30m speed (R2=0.724, P<0.001) and acceleration phase (S0-15m, R2=0.566, P<0.001). Maximum speed phase was best explained by SJ (S15-30m, R2=0.530, P<0.001). The model including FFM, gender, VJ-d, and maturity predicted S30m (R2=0.780, SEE=0.28m/s) and S15-30m (R2=0.698, SEE=0.51m/s). For S0-15m, the predictors were CMJA, impedance index, and SP (R2=0.610, SEE=0.36m/s). CONCLUSION: In accordance with other studies, sprinting performance was partially dependent on FFM and maturity. As expected, participation in organized sports seems to affect positively S30m and acceleration performance but did not explain maximal speed phase. Overall, the results highlight the relevance of BC and jump tests as a plausible model to track sprint performance in children and adolescents.

Muscle morphology of the vastus lateralis is strongly related to ergometer performance, sprint capacity and endurance capacity in Olympic rowers

ABSTRACTRowers need to combine high sprint and endurance capacities. Muscle morphology largely explains muscle power generating capacity, however, little is known on how muscle morphology relates to rowing performance measures. The aim was to determine how muscle morphology of the vastus lateralis relates to rowing ergometer performance, sprint and endurance capacity of Olympic rowers. Eighteen rowers (12♂, 6♀, who competed at 2016 Olympics) performed an incremental rowing test to obtain maximal oxygen consumption, reflecting endurance capacity. Sprint capacity was assessed by Wingate cycling peak power. M. vastus lateralis morphology (volume, physiological cross-sectional area, fascicle length and pennation angle) was derived from 3-dimensional ultrasound imaging. Thirteen rowers (7♂, 6♀) completed a 2000-m rowing ergometer time trial. Muscle volume largely explained variance in 2000-m rowing performance (R2 = 0.85), maximal oxygen consumption (R2 = 0.65), and Wingate peak power (R2 = 0.82). When normalized for differences in body size, maximal oxygen consumption and Wingate peak power were negatively related in males (r = −0.94). Fascicle length, not physiological cross-sectional area, attributed to normalized peak power. In conclusion, vastus lateralis volume largely explains variance in rowing ergometer performance, sprint and endurance capacity. For a high normalized sprint capacity, athletes may benefit from long fascicles rather than a large physiological cross-sectional area.

Effects of the Nordic Hamstring exercise on sprint capacity in male football players: a randomized controlled trial

ABSTRACT This assessor-blinded, randomized controlled superiority trial investigated the efficacy of the 10-week Nordic Hamstring exercise (NHE) protocol on sprint performance in football players. Thirty-five amateur male players (age: 17–26 years) were randomized to a do-as-usual control group (CG; n = 17) or to 10-weeks of supervised strength training using the NHE in-season (IG; n = 18). A repeated-sprint test, consisting of 4 × 6 10 m sprints, with 15 s recovery period between sprints and 180 s between sets, was conducted to evaluate total sprint time as the primary outcome. Secondary outcomes were best 10 m sprint time (10mST) and sprint time during the last sprint (L10mST). Additionally, peak eccentric hamstring strength (ECC-PHS) and eccentric hamstring strength capacity (ECC-CAPHS) were measured during the NHE. Ten players were lost to follow-up, thus 25 players were analyzed (CG n = 14; IG n = 11). Between-group differences in mean changes were observed in favor of the IG for sprint performance outcomes; TST (−0.649 s, p = 0.056, d = 0.38), 10mST (−0.047 s, p = 0.005, d = 0.64) and L10mST (−0.052 s, p = 0.094, d = 0.59), and for strength outcomes; ECC-PHS (62.3 N, p = 0.006, d = 0.92), and ECC-CAPHS (951 N, p = 0.005, d = 0.95). In conclusion, the NHE showed small-to-medium improvements in sprint performance and large increases in peak eccentric hamstring strength and capacity. Trial Registration Number: NCT02674919

Functional power training in children with CP: Does increased sprinting capacity lead to improvement in gait kinematics?

Functional power training in children with CP: Does increased sprinting capacity lead to improvement in gait kinematics?