Sprint Time Research Articles

Can caffeine improve early morning physical performance in team athletes?

Team-athletes often perform sub-optimally in early morning qualifiers and competitions (Drust et al., 2005, Chron Int, 22, 21-24). This study investigated whether caffeine could improve morning physical performance. Ten team-sport male athletes underwent four sessions [age (mean ± SD) 21 ± 1 years, stature 180 ± 5 cm, body mass 79 ± 9 kg]. These included two familiarisation sessions, one control (no pill) session and a caffeine pill (3 mg/kg body mass) session. Participants woke at 06:30h for all conditions (consuming the caffeine at 06:30 h) before arriving in the laboratory at 07:00 h. Temperature, lactate and glucose were recorded prior to mood states (POMS) and hand-grip strength. Thereafter, a warm -up (10 km/h for 5-mins on a treadmill), 10-mins of dynamic stretching and three build up 20m sprints of 50, 70, and 90% effort were undertaken. Temperature, lactate, and glucose were then measured. The repeated sprint performance (RSP) test was undertaken in 10 × 20 m RS on an indoor runway with 30 s recovery. Following each sprint; time was recorded via cameras and reflectors (Witty, UK); heart rate (HR) was recorded via a heart rate monitor on the upper arm connected to the POLAR app; thermal comfort and RPE were taken from participant verbal feedback. After the RSP, temperature, lactate and glucose were taken a final time. It was found that caffeine did not have an effect on sprint time (F1, 9 = 1.33, P = 0.278, ES = 0.129). However, sprint time for caffeine (3.16 m/s, s = 0.2) was quicker than that of no pill (3.18 m/s, s = 0.2). There was no difference (95% CI of the mean difference= −1.527 to 0.267) between caffeine and no pill on RPE. Handgrip strength for caffeine (45.65 kg, s = 9) was higher than that of no pill (44.48 kg, s = 10) and glucose levels for caffeine were higher and lactate levels lower than that of no pill, although not significantly. There was an effect of caffeine on ‘happy’ POMS score (P = 0.006). These results showed that caffeine did improve early morning physical performance for team-athletes, although not significantly. The effectiveness of caffeine as an ergogenic aid to improve early morning physical performance was challenged but needs to be investigated further, with a larger sample, to establish levels of significance.

The physical capabilities of national league female American Flag Football players

Flag Football is the fastest growing format of American Football and is a recent addition to the 2028 Olympics. The Flag format is a non-contact version of American Football, where tackles are made by removing flags from players hips. Activity profiles in the NFL (Sanchez et al., 2013, App Sci, 13:9278; Wellman et al., 2016, J Strength Cond Res, 30, 11–19) have highlighted the need for high levels of strength, power, and speed. Given the similarities within Flag, these physical capabilities may be equally applicable to Flag players. However, a lack of literature on the Flag format, and the paucity of research in female football, irrespective of format, exists. Therefore, the aim of this study was to explore the physical fitness capabilities of a national league Women’s Flag Football team. Fourteen participants (age 28 ± 5 years; stature 166 ± 8 cm; mass 79 ± 29 kg) from a national league Women’s Flag team took part in a physical fitness testing battery comprising; countermovement jump (CMJ), squat jump (SJ), broad jump (BJ), 20-yard sprint and shuttle, and the Isometric mid-thigh pull (IMTP). Participants were familiarised with testing procedures and initially completed a standardised warm-up. Mean and SD results from the jump assessments were as follows; CMJ jump height 25.1 ± 5.9 cm, peak power 39.1 ± 7.1 w/kg; SJ jump height 24.6 ± 6.3 cm, peak power 39.3 ± 6.6 w/kg; broad jump 1.89 ± 0.28 m. Absolute and relative peak force in the IMTP was 2201 ± 422 N and 30.1 ± 4.1 N/kg respectively. The Dynamic Strength Index (DSI) calculated from CMJ and IMTP peak force was 0.76 ± 0.12. Lastly, 20-yard sprint and shuttle times were 3.43 ± 0.28 and 5.36 ± 0.38 s respectively. Significant correlations were found between mean CMJ jump height and mean sprint time (p 0.001; r = −0.780), between mean CMJ jump height and mean shuttle time (p <.001; r −0.857), between mean BJ distance and mean shuttle time (p <0.01; r = 0.870) and between mean BJ distance and CMJ jump height (p <.001; r = −0.911). This study is the first of its kind to report the physical capabilities of female flag football players. The findings of this study may help develop the understanding of a growing and soon to be Olympic sport.

Acute effects of eccentric overload training with different loading doses in male sprinters

ObjectiveThe primary objective of this study was to investigate the immediate effects of two doses (Dose1 and Dose2,D1 and D2) of inertial Flywheel Eccentric Overload (FEOL), Eccentric Hook (EH), and High-intensity Half Squat (HHS) on muscle explosiveness in male sprinters. MethodsTwenty-one sub-elite male sprinters were randomly assigned to three groups: the FEOL group (n=7), the EH group (n=7), and the HSS group (n=7),Measurements of athletes' explosive jumps (CMJ, SJ, SLJ) heights, relative peak power indices, and 30-m sprint times were collected before and 6 min after the intervention. ResultsAt D1 loading dose, CMJ, SJ jump height, and relative peak power increased significantly (p < 0.05) after HHS training intervention, while there was no significant change in FEOL and EH training (p > 0.05). At D2 loading dose, CMJ, SJ jump height, and relative peak power increased significantly (p < 0.01) after FEOL and EH training intervention, but at D2HHS intervention, these indexes tended to decrease (p < 0.05). None of the three training protocols significantly improved SLJ performance (p > 0.05). CMJ vertical jump height and relative peak power were significantly higher after D2FEOL and D2EH interventions than after D1HHS (P < 0.05). ConclusionD1HHS, D2FEOL and D2EH3 intervention methods can all improve the performance of sub-elite athletes in the 30-m test, CMJ test and SJ test. in the CMJ test, FEOL training demonstrated a higher acute augmentation effect compared to EH training.

Microdosing Plyometric Training Enhances Jumping Performance, Reactive Strength Index, and Acceleration among Youth Soccer Players: A Randomized Controlled Study Design.

Microdosing can facilitate better accommodation to the training stimulus while aligning with the scheduling needs of teams. In this study, the effectiveness of microdosing exposure was investigated by comparing the effects of microdosing plyometric jump training (microPJT) with those of regular plyometric jump training (regPJT) and a control group not exposed to plyometric training. The comparison focused on the effects on jumping performance, reactive strength index (RSI), and acceleration over a 10-meter distance. Fifty-two male youth soccer players (16.3 ± 0.6 years old) from under-17 teams participated in a randomized controlled study, with interventions lasting 8 weeks. Assessments were conducted twice, before and after the intervention, measuring squat jump (SJ), countermovement jump (CMJ), RSI during drop jumps, and acceleration in a 10-meter sprint test. The regPJT group completed 34 bilateral jumps and 48 unilateral jumps per week over two weekly sessions, totaling 82 jumps. Conversely, the microPJT group performed 17 bilateral jumps and 24 unilateral jumps weekly over 4 sessions week, totaling 41 jumps. Significant interactions between groups and time were observed concerning SJ (p < 0.001; η2= 0.282), CMJ (p < 0.001; η2= 0.368), RSI (p < 0.001; η2= 0.400) and 10-m sprint time (p < 0.001; η2 = 0.317). Between-group analysis indicated that both the microPJT (p < 0.001) and regPJT (p < 0.001) groups exhibited significant better results compared to the control group in post-intervention evaluation of SJ, CMJ, RSI and 10-m sprint time, while no significant differences were found between experimental groups (p > 0.050). In conclusion, this study has revealed that both microPJT and regPJT are equally effective in enhancing jumping performance and acceleration time in soccer players. This suggests that a smaller training volume, distributed more frequently across the week, can effectively induce improvements in soccer players.

Assessing the Effectiveness of Speed, Agility, and Quickness (SAQ) Training on Performance among Senior and Junior Female Kho-Kho Players in Mumbai Region

Abstract: This study examines the impact of an eight-week Speed, Agility, and Quickness (SAQ) training program on senior and junior female Kho-Kho players in Mumbai. Sixty players were evenly divided into experimental and control groups. Results show significant improvements in SAQ-trained players’ performance, including enhanced speed, agility, and quickness observed through reduced completion times in Kho-Kho drills. ANOVA analysis indicates statistically significant differences in performance between experimental and control groups across various parameters. SAQ-trained groups consistently outperformed controls in sprint times, agility test scores, and reaction times. For instance, seniors in the experimental group improved from a pre-training mean sprint time of 12.5 sec to 10.8 sec post-training, while juniors improved from 13.2 sec to 11.2 sec. In contrast, control group means remained relatively unchanged. Similarly, experimental groups exhibited substantial enhancement in agility test scores and reaction times compared to controls. Seniors’ agility scores increased from a pre-training mean of 18 points to 24 points post-training, and juniors’ scores improved from 16 points to 22 points. Reaction times for both senior and junior experimental groups decreased notably post-training, whereas control groups showed minimal change. These findings emphasize the significance of integrating SAQ training into the routine of female Kho-Kho players, regardless of their age or skill level. Such training interventions hold promise for augmenting players’ physical capabilities and overall performance, thereby bolstering their competitiveness in Kho-Kho tournaments.

Potential Benefits of Postactivation Potentiation Protocols on Tennis Performance: A Systematic Review

ABSTRACT The study aimed to provide an overview of the benefits of postactivation potentiation (PAP) protocols on tennis performance. All procedures were in accordance with the PRISMA guidelines. After an online search, 8 studies with 133 tennis players were eligible for inclusion. Results showed that a variety of methods were used to elicit PAP in tennis players, with maximal voluntary isometric contraction showing promising results in improving serve velocity (SV) by 4.6 km·h−1 (3.4 ± 4.6%; ES = 0.711) immediately after the preconditioning activity (PCA). The most favorable effects of PAP on sprinting time and maximal power were observed in resistance training exercises using squats as PCA, with loads near 60% of 1 repetition maximum (1RM), whereas the heavy load leg press warm-up demonstrated positive effects on agility and power. By contrast, negative effects on SV were observed with heavy 600-g ball throws. Despite limitations in match application because of the post-activation performance enhancement effect duration, these protocols remain beneficial for training purposes. Calculating volume load relative to 1RM can provide helpful insights for optimal PAP. However, individualizing PAP protocols based on athletes' characteristics and training status seems crucial and should be investigated in future studies.

Abdominal Fatigue Impairs Anaerobic, but not Aerobic,Cycling Performance in Untrained Adults

Relevance. Coaches and athletes across a variety of sports commonly perform abdominal exercises to promote core strength and endurance. However, the precise influence of abdominal strength and endurance on cycling performance remains elusive. Purpose. Determine whether abdominal fatigue affects anaerobic sprint and aerobic time- trial (TT) cycling performance. Methods. Twenty-three untrained young adults (age: 19,2 ± 1,0 years, height: 170,4 ± 7,5 cm, and weight: 74,5 ± 14,1 kg) participated in this study. Twelve of the participants completed two Wingate anaerobic power tests on a Monark 834 E ergometer set at 7,5 % of body mass and the remaining 11 participants completed two 3,2 km cycling TTs on an Expresso S3U virtual reality bike; tests were separated by 96 hours. All participants performed abdominal crunches to fatigue prior to the second test. Dependent t-tests were used to assess differences between the cycling trials for the two groups. Results. Abdominal muscle fatigue decreased mean anaerobic power (Pre: 486,75 vs. Post: 408,83 Watts (W, p &lt; 0,001), increased the rate of fatigue (Pre: 42,01 vs. Post: 50,32 %, p = 0,004), and tended to decrease peak anaerobic power (Pre: 643,17 vs. Post: 607,27 W, p = 0,088). However, abdominal muscle fatigue did not affect TT mean power (Pre: 228,18 vs. Post: 220,09 W, p = 0,127) or TT performance (Pre: 382,7 vs. Post: 388,0 seconds, p = 0,222). Conclusion. Abdominal fatigue negatively affects anaerobic cycling performance in untrained young adults. Future studies should evaluate the impact of abdominal fatigue on cycling performance in trained cyclists.

Advancing 100m sprint performance prediction: A machine learning approach to velocity curve modeling and performance correlation.

This study presents a novel approach to modeling the velocity-time curve in 100m sprinting by integrating machine learning algorithms. It critically addresses the limitations of traditional speed models, which often require extensive and intricate data collection, by proposing a more accessible and accurate method using fewer variables. The research utilized data from various international track events from 1987 to 2019. Two machine learning models, Random Forest (RF) and Neural Network (NN), were employed to predict the velocity-time curve, focusing on the acceleration phase of the sprint. The models were evaluated against the traditional exponential speed model using Mean Squared Error (MSE), with the NN model demonstrating superior performance. Additionally, the study explored the correlation between maximum velocity, the time of maximum velocity occurrence, the duration of the maximum speed phase, and the overall 100m sprint time. The findings indicate a strong negative correlation between maximum velocity and final time, offering new insights into the dynamics of sprinting performance. This research contributes significantly to the field of sports science, particularly in optimizing training and performance analysis in sprinting.

Exploring Gender-Based Disparities in Speed, Agility, and Quickness Attributes Among Kho-Kho Players in Mumbai: A Comparative Study

This study aims to investigate the gender-based differences in speed, agility, and quickness (SAQ) attributes among Kho-Kho players in Mumbai, India. Kho-Kho, a traditional Indian sport, requires rapid changes in direction, acceleration, and deceleration, making SAQ crucial for performance. Despite the sport's popularity, there is limited research on gender-specific SAQ characteristics among Kho-Kho players. The study recruited 100 Kho-Kho players (50 males and 50 females) from various clubs and institutions in Mumbai. Participants underwent a series of SAQ tests, including the 40-yard dash, T-test, and Illinois agility test, to assess their speed, agility, and quickness. Results revealed significant gender-based differences in SAQ attributes among Kho-Kho players. Male participants exhibited superior performance in speed-related tests, such as the 40-yard dash, demonstrating faster sprint times compared to females. Conversely, females demonstrated greater agility and quickness in tests like the T-test and Illinois agility test, indicating superior multidirectional movement capabilities. These findings suggest that while male Kho-Kho players excel in straight-line speed, female players possess advantages in agility and quickness, possibly due to differences in biomechanical and physiological factors. Understanding these gender-specific differences can inform training programs tailored to enhance specific SAQ attributes in male and female Kho-Kho players, potentially optimizing their performance and reducing the gender gap in sports. Further research is warranted to explore the underlying mechanisms contributing to these disparities and develop targeted interventions to address them.

REGULAR LOW-DOSE CAFFEINE SUPPLEMENTATION DURING TRAINING DOES NOT PROVIDE ADDITIONAL BENEFIT TO SUBSEQUENT EXERCISE PERFORMANCE IN AUSTRALIAN RULES FOOTBALL ATHLETES

INTRODUCTION &amp; AIMS Acute caffeine supplementation can improve exercise types like those completed by Australian Rules football (ARF) players during training. Hypothetically athletes could implement caffeine supplementation prior to training, allowing them to complete more training volume, improving adaptation and subsequent exercise performance. This study aimed to investigate the effect of regular low-dose caffeine ingestion pre-training during a training block on subsequent exercise performance. METHODS Twenty-nine male semi-professional ARF players were randomly allocated to a caffeine or placebo group. The four-week intervention period involved participants ingesting 2 mg·kg·BM-1 of caffeine or a placebo 60 min prior to two of their three weekly training sessions, which incorporated sport-specific conditioning and skills training. To assess exercise performance, a battery of tests was used before and after the intervention period including the Yo-Yo Intermittent Recovery Test Level 2 (YYIRT2), 20 m sprint and vertical jump (VJ). Performance differences were assessed using a linear mixed-effect model. RESULTS Mean session rating of perceived exertion (p = .24) and total training load (p =.53) were not different between caffeine and placebo groups over the intervention. There were no significant time x condition interaction effects for YYIRT2 accumulated distance (p = .87), or 5, 10 and 20 m sprint times (p =.06 - .44), however both caffeine and placebo groups improved YYIRT2 distance and sprint times following four weeks of training (p &amp;lt; 0.01). There was a significant effect for time showing decreased VJ performance (p &amp;lt; 0.01), with greater reductions in the placebo group (p = .03). CONCLUSION It is more beneficial to implement an effective training program for athletes rather than focusing effort on regular low-dose caffeine supplementation to augment the training stimulus. The training stimulus itself is typically greater for developing endurance and sprint effort performance, with supplemental caffeine showing no additional performance benefit.

Relationship Between Individual and Composite FMS™ Scores with the Anthropometric and Physical Characteristics of Elite Touch (Rugby) Players

Abstract Purpose To describe and compare the movement patterns, anthropometric and physical characteristics of male and female Touch players; and examine the relationships between Functional Movement Screening (FMS™) scores and the anthropometric and physical characteristics. Methods This was a cross-sectional study with 35 elite Touch players (18 males, age = 24.7 ± 4.9 years; 17 females, age = 26.7 ± 5.2 years). Anthropometric (stature, body mass) and physical characteristics (sprint times, glycolytic change-of-direction test, and countermovement jump (CMJ) flight time and peak power) were assessed alongside movement patterns using the FMS™ battery. Data were analysed for between-sex differences (independent t-test, Mann–Whitney U) and relationships (Spearman’s correlation coefficient). Results Between-sex differences in body mass (t = 6.082, P &lt; 0.001), stature (t = 9.247, P &lt; 0.001), CMJ flight time (t = 3.576, P = 0.001), relative CMJ peak power (t = 6.578, P &lt; 0.001), 10 m sprint time (t = 15.861, P &lt; 0.001), glycolytic change of direction test time (t = − 11.831, P &lt; 0.001) and Yo–Yo IR1 (t = 6.842, P &lt; 0.001) were observed. There were minimal differences for deep squat (Z = − 1.036, P = 0.443), in-line lunge (Z = − 1.284, P = 0.303), shoulder mobility (Z = − 0.173, P = 0.883), trunk stability push-up (Z = − 0.896, P = 0.483) and rotary stability (Z = − 1.537, P = 0.273). The correlation between total and individual FMS™ scores with anthropometric and physical characteristics ranged from trivial-to-moderate (r = − 0.502 to 0.488). Conclusion The lack of difference for the FMS™ composite score and small-to-trivial differences in individual scores allows a comparison between mixed populations within Touch. Whilst many of the correlations were trivial-to-small, there were differences between sexes in the associations and evidence that improvements in functional deficiencies could translate into improved physical performance.

A comparative study of 8-week complex training and resistance training on athletic performance of amateur futsal players.

Background: Despite the acknowledged importance of resistance training (RT) in enhancing physical performance in futsal players., the comparative effectiveness of RT and complex training (CT) on both physical and technical performance in futsal players remains underexplored. This study aimed to compare the effects of RT vs. CT on physical and technical performance in amateur futsal players. Method: Players from two amateur futsal teams were assigned to RT (one team of 16 players; 18years) and CT (one team of 16 players; 18 years) to perform an 8-week intervention with two weekly sessions. The RT performed the squat and deadlift (6 sets of 6-10 repetitions at 75%-85% one-repetition maximum (1RM), while the CT performed the squat + squat jump and deadlift + high pull (3 sets of 4-6 + 10-12 repetitions at 75%-85% 1RM). Pre- and post-intervention assessments included the Futsal Special Performance Test (FSPT), repeated sprint ability (RSA), sprint decrement (Sdec), sprint times at 10-m (T10), 10-20-m (T10-20), and 20-m (T20), 1RM back squat (1RM BS), isometric mid-thigh pull (IMTP), and countermovement jump (CMJ). Results: At baseline, no significant differences between groups were observed for any variable analyzed (p > 0.05). After 8weeks, there were significant differences between CT vs. RT on FSPT (-10.8% vs. -3.4%; p < 0.05), T10 (-5.2% vs. -0.1%; p < 0.05), IMTP (7.8% vs. 5.1%; p < 0.05), and CMJ (10.2% vs. 4.5%; p < 0.05). On the other hand, no significant differences between CT vs. RT were observed for RSA (-2.0% vs. -1.2%; p > 0.05), Sdec (-7.6% vs. -3.5%; p > 0.05), T10-20 (-0.9% vs. -0.9%; p > 0.05), T20 (-1.8% vs. -1.7%; p > 0.05), and 1RM BS (5.7% vs. 4.5%; p > 0.05) after the training program. Both groups significantly improved FSPT, T20, 1RM BS, and IMTP, while only CT significantly improved RSA, Sdec, T10, and CMJ. Conclusion: The results suggest that CT may be valuable for improving specific performance parameters in amateur futsal players, with some advantages over RT in enhancing strength and power. These findings support tailored training protocols for futsal players to optimize performance.

The Association of Countermovement Jump, Isometric Mid-Thigh Pull, and On-Ice Sprint Performance in University Level Female and Male Ice Hockey Athletes

On-ice skating sprint performance is a significant predictor and requirement for playing at the highest levels of hockey. The purpose of this study was to determine the relationship between maximum and dynamic strength measures and on-ice sprint performance in university level ice hockey athletes. Both male (n=18) and female (n=13) hockey players participated in this study. The off-ice measures included two assessment procedures utilizing a force plate; an isometric mid-thigh pull (IMTP) to assess maximum strength and a countermovement jump (CMJ) to assess dynamic strength. Both off-ice measures were analyzed from both a relative (CMJr and IMTPr) and absolute (CMJa and IMTPa) perspective. The on-ice measures were 7.71m and 15.42m sprint times. Pearson product moment correlations were used to quantify the relationships between variables. CMJa (r = -0.56 to -0.61), IMTPa (r = -0.65 to -0.67) and IMTPr (r = -0.55) were significantly correlated (p &lt; 0.05) with on-ice sprint performance. When analyzed by sex, no significant relationships (p &gt; 0.05) were observed between CMJ measures and on-ice sprint times. No significant relationships (p &gt; 0.05) were observed between IMTP measures and on-ice sprint times when individually analyzing male participants, while significant relationships (p &lt; 0.05) were observed in females between IMTPa (r = -0.70 to -0.71) and IMTPr (r = -0.68 to -0.71) and on-ice sprint times. It is concluded that both maximum and dynamic strength are important factors in on-ice sprint performance in hockey players. Furthermore, maximum strength seems to be an important characteristic in on-ice sprint ability in females.

The Association between Countermovement Rebound Jump Metrics and Independent Measures of Athletic Performance

This study investigates the associations between countermovement rebound jump (CMRJ) performance metrics and various independent measures of athletic performance, including the isometric mid-thigh pull (IMTP), 20 m linear sprint, and 505 change-of-direction (COD) speed tests. Pearson’s correlations were used to analyse the relationship between the CMRJ measures with athletic performance, with significance being set at p ≤ 0.006. Results showed large significant positive relationships between IMTP peak force and force at 300 milliseconds with the first jump height of the CMRJ (JH-1, r = 0.54 to 0.55, p ≤ 0.002). Additionally, inverse relationships were observed between reactive strength index modified (RSImod) and reactive strength index (RSI) with 20 m sprint total and split times (r = −0.55 to −0.66, p ≤ 0.001), and the 10 m and total sprint times were significantly correlated with JH-1 (r = −0.54, p = 0.003), indicating that greater vertical explosive power and reactive strength are associated with faster sprint performance. Finally, a significant inverse relationship was identified between CMRJ metrics (two JH values and RSImod) and 505 COD times in both the left and right sides (r = −0.51 to −0.68, p ≤ 0.006). These findings suggest that CMRJ performance metrics are valuable indicators of lower-limb explosive force production, with a strong link to both linear sprint and COD performance. The finding underscores the importance of including CMRJ assessments in athletic performance evaluations due to their dual assessment capacity of slow and fast stretch–shortening cycle mechanics.

Sex differences in muscle morphology between male and female sprinters.

There is a marked difference between males and females in sprint running performance, yet a comprehensive investigation of sex differences in the muscle morphology of sprinters, which could explain the performance differences, remains to be completed. This study compared muscle volumes of 23 individual leg muscles and 5 functional muscle groups, assessed with 3 T magnetic resonance imaging, between male (n = 31) and female (n = 22) sprinters, as well as subgroups of elite males (EM, n = 5), elite females (EF, n = 5), and performance-matched (to elite females) males (PMMEF, n = 6). Differences in muscle volume distribution between EM, EF, and unathletic male (UM) controls were also assessed. For the full cohorts, male sprinters were more muscular than their female counterparts, but the differences were nonuniform and anatomically variable, with the largest differences in the hip extensors and flexors. However, among elite sprinters the sex differences in the volume of the functional muscle groups were almost uniform (absolute volume +47-53%), and the muscle volume distribution of EM was more similar to EF than to UM (P < 0.039). For PMMEF, relative hip extensor volume, but not stature or percent body fat, differentiated for performance (PMMEF and EF < EM) rather than sex. In conclusion, although the full cohorts of sprinters showed a marked sex difference in the amount and distribution of muscle mass, elite sprinters appeared to be selected for a common muscle distribution phenotype that for these elite subgroups was a stronger effect than that of sex. Relative hip extensor muscle volume, rather than stature, percent body fat, or total relative muscle volume, appeared to be the primary determinant of the sex difference in performance.NEW & NOTEWORTHY We present novel evidence suggesting muscle volume, specifically relative hip extensor volume, may be a primary deterministic variable for the sex difference in sprint performance, such that with matched sprint times, male and female sprinters may be expected to have equivalent muscle morphology. We highlight striking similarities in distribution of leg muscle mass between elite male and female sprinters and provide evidence for the existence of a muscular distribution phenotype specific to elite sprinters, irrespective of sex.

Caffeine Improves Sprint Time in Simulated Freestyle Swimming Competition but Not the Vertical Jump in Female Swimmers.

Caffeine (CAF) has been shown to be an effective ergogenic aid in enhancing sports performance, including vertical jump (VJ), sprint, balance, agility, and freestyle swimming performance (FSP). However, whether acute CAF supplementation improves FSP in moderately trained female swimmers has not been well documented. Therefore, this study aimed to investigate the effects of CAF intake on vertical jump, balance, auditory reaction time (ART), and swimming performance in female swimmers. In a double-blind, cross-over design, eight moderately trained female swimmers (age: 21.3 ± 1.4 years, height: 161.2 ± 7.1 cm, body mass: 56.3 ± 6.7 kg, body mass index (BMI): 21.9 ± 1.3 kg/m2, and habitual CAF intake: 246.4 ± 111.4 mg/day) ingested caffeine (CAF) (6 mg/kg) or a placebo (PLA) 60 min before completing VJ, balance, ART, and 25/50 m FSP. CAF supplementation resulted in a significantly lower time both in 25m (p = 0.032) and 50m (p = 0.033) FSP. However, CAF resulted in no significant difference in VJ, ART, and RPE (p > 0.05). Balance test results showed a non-significant moderate main effect (d = 0.58). In conclusion, CAF seems to reduce time in short-distance swimming performances, which could be the determinant of success considering the total time of the race. Thus, we recommend coaches and practitioners incorporate CAF into swimmers' nutrition plans before competitions, which may meet the high performance demands.

Strength Training Frequency and Athletic Performance in High School Girls Basketball Players.

This study investigated the effects of a six-week strength training intervention on the physical fitness of female high school athletes, with a focus on training frequency. Twenty-three female high school basketball athletes were recruited and split into two groups: one group participated in strength training once per week (S1), while the other participated in two training sessions per week (S2). The groups were not random as training sessions were voluntary, and some participants were only able to train once per week. Participants were tested before and after the intervention, and the data included: age, body height, body mass, body fat percentage, grip strength, leg/back dynamometer (LBD) strength, a seated medicine ball throw (MBT), a vertical jump (VJ), 505 tests from each foot, 0-5, 0-10, and 0-20 sprint times, and multistage fitness test shuttles. Data were analyzed by a two (time) x two (group) repeated measures analysis of variance (ANOVA; p < 0.05). When significant F ratios were detected in any ANOVA calculations, post hoc pairwise comparisons were conducted using the Bonferroni adjustment procedure. There were significant main effects for time that indicated the following: increased body height, body mass, grip strength, LBD strength, MBT distance, and VJ height, faster 505 times, and slower 0-5 and 0-10 m sprint times (p ≤ 0.021). There were no significant time by group ANOVAs or between-group main effects. These performance changes occurred irrespective of training frequency. High school girls who participate in at least one strength training session per week can improve their strength (grip, LBD), power (MBT, VJ), and change-of-direction speed (505).

Repeated-sprint sets test: a new method for evaluating and forecasting fitness in elite young male soccer players

The objective of the current study was to explore the correlation between repeated sprint sets (RSS) ability and several physical attributes, including maximum sprint speed, maximal aerobic speed, maximal anaerobic speed, aerobic capacity, and explosive strength. Moreover, the aim was to assess the suitability of RSS as a comprehensive evaluation tool for physical qualities and to determine which physical field tests most accurately predict RSS in elite young male soccer players. A total of thirty-two young elite male soccer players (mean age 14.6 ± 0.3 years; predicted years from peak height velocity (PHV): − 0.4 ± 0.3; years in training: 3.7 ± 0.5) voluntarily participated in the study. The players participated in eight consecutive specific physical tests, with a minimum 72-h recovery between each session to minimize the impact of fatigue during the second trial. The participants completed the tests in the following order: RSS test, Vam-Eval test, a constant velocity test performed until exhaustion at 100% of vVO2max (tlim100), 20-m Multi-Stage Shuttle Run test (VMSRT), Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), Maximal Anaerobic Shuttle Running Test (VMASRT), Maximal Sprinting Speed Test (20-m flying sprint), Countermovement Jump (CMJ), and Standing Long Jump test (SLJ). The results of the study showed that there were very large negative correlations between tlim100 and SST (sum of sprint times), and large negative correlations between Yo-Yo IR1, Vam-Eval, and SST during RSS in young elite male soccer players (p < 0.05). Additionally, VMASRT and SLJ demonstrated a moderate negative correlation with SST (p < 0.05). In contrast, significant positive correlations were found between 20-m flying sprint and the SST (p < 0.05). According to the stepwise multiple linear regression analysis, the primary predictors of SST, ranked by importance, were tlim100 and Yo-Yo IR1. These two predictors collectively accounted for 72% of the variance in players’ SST (p < 0.0001). Due to the importance of aerobic capacity and short repeated accelerations/sprint sets for overall competitive performance in soccer, in conclusion, our results suggest that elite young male soccer players should perform both high intensity interval training and aeorobic capactity exercises as part of soccer training if the primary outcome is to improve repeated sprint ability performance.

Effects of vertical and horizontal plyometric training on jump performances and sprint force-velocity profile in young elite soccer players.

During a soccer match, horizontal acceleration ability during short sprints is determinant for performance. Development of sprint force and velocity qualites have been reported after plyometric training. However, orientation of plyometric training exercises can influence the functional performance. The purpose of this study was to compare the horizontal and vertical orientation of plyometric training on explosiveness performances and sprint force-velocity profile in young soccer players. Twenty-eight soccer players were recruited and divided in two groups: vertical (VG, n = 14) and horizontal (HG, n = 14) groups. Tests including jumps and sprint performances were conducted before and after the 8week training period. Sprint force-velocity profile (FVP) was evaluated during a 30m sprint test. The results demonstrated significant improvements in both VG and HG for jump performances (from + 4.9% to + 9.0%), sprint times (from -5.5% to -8.7%) and FVP parameters. Higher relative changes for the HG than for the VG were observed in 5m and 15m sprint times, horizontal jump lengths, and also in FVP parameters, especially improvements in maximal power (VG: + 16.4% vs. HG: + 28.1%) and inthe decrease rate of horizontal orientation of force with increasing speed (HG: + 22.9%) during the 30m sprint. Both horizontal and vertical plyometric training can be either used in young soccer players to improve vertical and horizontal performances in jump and sprint. However, horizontal plyometric training may result in a greater improvement in horizontal ballistic actions while similarly developing vertical jump qualities compared to vertical plyometric training in young soccer players.

A New Method for Evaluating the Reactive Strength Index in Track and Field Sprinting: Relationships with Muscle Architecture

The aim of the present study was to assess a new reactive strength index (RSI RUN) based on contact time and stride length measured in sprint running and then to correlate this index with sprint performance, muscle architecture and echo intensity of the vastus lateralis. Participants included ten elite and sub-elite sprinters (age 24.4 ± 3.1 years, height 177.5 ± 7.7 cm, mass 69.8 ± 11.7 kg) who were tested with a vertical drop jump (VDJ) and a horizontal drop jump (HDJ) from a 30 cm high box, a 20 m straight-leg running drill (SLR) and a 60 m sprint. A nearly perfect correlation (r = from −0.90 to −0.96, p &lt; 0.01) was detected between RSI RUN and sprint performance (30 m, 60 m and 100 m sprint time), and a very large correlation (r = from −0.72 to −0.77, p &lt; 0.05) was found between the traditional RSI from vertical drop jump (RSIDJV) and sprint performance. In addition, the RSI RUN was more correlated to sprint performance than other RSI indices studied in previous research. The echo intensity of the vastus lateralis (VLEI) was largely correlated with maximum running speed (r = from 0.76 to 0.87, p &lt; 0.05) and the RSI RUN (r = −0.80, p &lt; 0.05). No significant correlations were noted between echo intensity and other RSIs. In conclusion, the RSI RUN and VLEI seem to be good predictors for track and field sprinting performance.