20-m Sprint Research Articles

Jump height ingenerated by countermovement and arm swing better correlates with proagility shuttle run tests but not with change of direction deficits in collegiate female athletes.

Jumping and linear sprinting performances show a moderate correlation with change of direction (COD) ability. However, the extent of these correlations remains unknown through statistical analysis. Thus, this study statistically compared correlation coefficients between COD, COD deficit (CODD), and jumping and linear sprint performances. National-level basketball (29) and baseball (18) intercollegiate female athletes performed 20-m linear sprint, proagility (5-10-5) test, squat jump (SJ), countermovement jump with (CMJarm) and without (CMJ) arm swing and modified reactive strength index (RSImod). Correlation analysis was used to assess factors correlated with COD performance and CODD; subsequently, correlation coefficient comparison test was used to determine better correlations with COD and CODD performance. CMJ (r=-0.483) and CMJarm (r=-0.446) had stronger correlations with 10-m COD (both, P<0.018) than with 10-m linear sprint (r=0.431, P=0.002). For 20-m COD, RSImod, CMJ, and CMJarm (r=-0.491--0.543, P<0.001) better correlated with 20-m COD than with 20-m linear sprints (r=0.436, P=0.002), while RSI (both r=-0.317, P<0.030) and SJ (r=-0.359, r=-0.293, P=0.046) were weakly correlated with 10- and 20-m COD. The differences in correlation coefficients for RSImod, CMJ, and CMJarm were not significant in both 10- and 20-m COD. Ten-meter linear sprint performance only correlated with 10-m CODD, while no correlation was observed with 20-m CODD. Stronger correlations of RSImod, CMJ, and CMJarm with 10-/20-m COD than with linear sprinting, RSI, and SJ suggest that training focused on improving countermovement and arm swings with jumping may enhance COD performance in female athletes.

Sprint performance following plyometric conditioning activity in elite sprinters

Introduction: Considering the significance of the ankle joint for sprinting with the spring-like properties of the Achilles tendon, it seems that plyometric activating exercises could significantly potentiate maximum velocity sprinting. Therefore, the objective of this study was to evaluate the effects of specific plyometric exercises engaging the ankle joint, called stiff-legged hops as a conditioning activity (CA) on countermovement jump (CMJ) and sprinting performance evaluated over a distance of 50m in elite female and male sprinters that differ in athletics level. Material and methods: Thirty-two sprinters of the Polish National Team were assigned into experimental and control (CTRL) groups, while the experimental group was further equally divided by the 50m sprint time (ELITE; S-ELITE). All participants performed pre-CA (5 min before) and post-CA (5 and 10 min after CA) CMJ and 50m sprints. The CA consists of 3 sets of 10 repetitions of stiff-legged hops, while the CTRL group did not perform any activity. Results: The stiff-legged hops had no significant effect on either CMJ or the 50 m sprint performance in both the ELITE and S-ELITE athletes. However, there was a significant increase in 20 m (p = 0.025; η2 = 0.162) and 30 m sprint time (p = 0.02; η2 = 0.172), with an increase in ground reaction time (p = 0.009; η2 = 0.211) in post-CA from pre-CA with no difference between the groups. The use of stiff-legged hops as a pre-sprint CA did not provide noticeable benefits or drawbacks in CMJ and 50 m sprinting among elite sprinters. However, it may even deteriorate 20 and 30 m performed due to increased ground reaction time. Conclusion: The results of this research do not provide evidence that supports the use of such CA in training or pre-competition contexts.

Effect of HIIT on Motor Performance in Female Handball Players

Abstract: The aim of this study was to investigate the effects of interval training at four different intensities in addition to handball training for 8 weeks on aerobic-anaerobic, speed and agility pa-rameters in female handball players. Twenty female handball players (experimental group: 10; control group: 10) voluntarily participated in the studyThe experimental group trained in high-intensity interval training (HIIT) 3 days a week for 8 weeks in addition to handball training, while the control group was allowed to continue their standard training program. The anaerobic capacity, speed, and agility of the experimental and control groups were measured twice before and after an 8-week training program. The HIIT training program for the experimental group was adapted to the movements most commonly used in handball. The values of the data obtained from the handball players were analyzed. ANOVA for mixed measures was applied to determine the difference between the pre-test and post-test values of the experimental and control groups. There was a statistically significant difference (p &lt; 0.05) between the pre and post-test values of the 20-m sprint test of the experimental and control groups of HIIT training for handball players, while there was no statistically significant difference between the pre and post-test values of the anaerobic capacity and agility test of HIIT training. In conclusion, it is recommended to include HIIT training in the training periodization of handball players during the season, and it is believed that it will have a positive effect on players' speed performance.

The Relationship Between Maximum Lower Limb Strength &amp; Power, and GPS Acceleration Speed in Elite U20 Gaelic Football Athletes

Previous research indicates positive relationships between high levels of lower limb strength and power, and acceleration sprint velocity in team sport athletes. This cross-sectional study aimed to investigate the relationship between lower limb absolute and relative strength, countermovement jump (CMJ) height, and Global Positioning System (GPS) recorded 20m acceleration sprint velocity in elite male U-20 Gaelic football athletes. Nineteen athletes (19.0 ± 0.5 years; 81.1 ± 5.5 kg; 182 ± 6.2 cm) from the same elite U-20 squad participated in this study during an in-season period. Subjects performed a &gt;95% 1RM box squat, a 20m sprint test, and a CMJ test. Relative maximum lower limb strength (r = 0.54, 95% CI [0.11 to 0.8]; p &lt; 0.05) and CMJ height (r = 0.66, 95% CI [0.29 to 0.86]; p &lt; 0.001) showed strong correlations with 20m sprint velocity. A multiple linear regression analysis demonstrated that lower limb maximum relative strength and CMJ height significantly predicted 20m sprint velocity (Adjusted R2 = 0.51, F (2, 16) = 6.29, p &lt; 0.05). These findings provide evidence for the importance of elite under-age Gaelic football athletes acquiring high levels of lower limb strength and power characteristics to enhance acceleration sprint performance.

The effects of neuro-vestibular-ocular exercises and myofascial release on proprioception and performance in football players with chronic ankle instability

BACKGROUND AND PURPOSE: Football players often use quick change of direction, sudden acceleration and explosive movements. This is why chronic ankle instability is one of the most common conditions affecting this athlete population. This study investigates the effects of neuro-vestibular-ocular exercises and myofascial release on proprioception and performance in football players with chronic ankle instability. MATERIALS AND METHODS: This randomized controlled clinical trial included 60 football players aged 18–30. The players were randomly divided into two groups. The first group (NVOEG, n=30) was included in the Neuro-Vestibular-ocular exercise training program, while the myofascial release was applied to the second group (MRHOG, n=30). Both protocols were applied for eight weeks. The participants’ Cumberland Ankle Instability Tool (CAIT) scores were assessed before and after the intervention. Proprioception was evaluated by using the joint position sense test. Additionally, kick speed (KS), 30-m sprint, zig-zag agility test (ZAT) and Landing error score system (LESS) tests were applied to evaluate their performance. RESULTS: Post-rehabilitation scores showed significant differences in proprioception and performance parameters compared to pre-scores in both groups. (p&lt;0.05). Significant differences were observed between the NVOEG and MRHOG in the post-test scores, including CAIT for unstable and stable ankle, proprioception for unstable ankle, LESS, ZAT with ball performance, and 30-meter sprint test. CONCLUSIONS: The neuro-vulvular-ocular exercise training protocol had superior results in terms of proprioception and performance parameters in chronic ankle instability management for football players.

Effects of different work-to-rest ratios of high-intensity interval training on physical performance and physiological responses in male college judo athletes

ObjectiveThis study aimed to compare the effects of high-intensity interval training (HIIT) with work-to-rest ratios of 2:1 and 3:1 on physical performance and physiological responses in male college judo athletes. MethodsForty-eight male college judo athletes were randomly assigned to one of three groups. One used HIIT with a 2:1 work-to-rest ratio (2:1 group), another used HIIT with a 3:1 work-to-rest ratio (3:1 group), while a control group (CG) continued its regular training program as before. Subjects completed two training sessions per week for 6 weeks. The participants completed the Modified Agility T-test, 30-m sprint, medicine ball put, countermovement jump, 20-m multistage shuttle run test, and 30-s Wingate test before and after the training, and blood lactate measurements at 3, 5, 10, and 15 min after the 30-s Wingate test were taken before and after the training. ResultsThe 2:1 group (p = 0.010, d = 0.88 (large)) and 3:1 group (p = 0.002, d = 0.46 (small)) showed significant improvements in VO2max estimated by the 20-m multistage shuttle run test in comparison with pre-test. The 3:1 group had a significant difference in agility in comparison with the CG post-training (p = 0.004). Peak power (PP) and relative peak power (PP/kg) significantly improved in the 3:1 group (p < 0.05) compared to the pre-test. Blood lactate values at the fifth minute (p = 0.029) after the Wingate test in the 3:1 group were significantly decreased compared to the pre-test. ConclusionOur findings suggest that HIIT with the 3:1 and 2:1 work-to-rest ratios can improve aerobic power, and HIIT with a 3:1 work-to-rest ratio can improve absolute and relative peak power.

The effect of different resistance and assistance loads on 30-m sprint kinematics.

Resisted sprint and assisted sprint are the two main types of training methods used by athletes in sprint training, so optimizing resisted sprint training and assisted sprint training process is beneficial for improving athletes' sprint performance. Kinematics is the most intuitive parameter that reflects the quality of training during running process, and it is particularly important to analyze the gait of athletes during resisted and assisted sprint process. Therefore, this paper investigates the effects of resisted and assisted sprint on the sprint kinematics of sprinters in the first 30 meters to demonstrate the targeted effects of resisted and assisted sprint training. The experimental results show that compared to the unloaded running, male collegiate sprinters increase their total step count, decrease their step length, increase their step time, increase their contact time, whereas have almost no change in the flight time when performing the 30-m resisted sprint. Male collegiate sprinters decrease their total step count, increase their step length, increase their step time, decrease their contact time and increase their flight time, when performing the 30-m assisted sprint. In addition, it is found that resisted sprint training is beneficial for improving the athletes' power and explosiveness during the acceleration phase, thereby improving acceleration ability. However, prolonged and frequent resisted sprint training may reduce the step length and step frequency of athletes. Assisted sprint training is beneficial for shortening the contact time of athletes, improving their step length and flight time, and enabling them to overspeed, thereby increasing their maximum speed ability.

Monitoring of sprint and change of direction velocity, vertical jump height, and repeated sprint ability in sub-elite female football players throughout their menstrual cycle

ABSTRACT Aims The aim of this study was to investigate the associations between the early follicular (EF, i.e., menstruation), late follicular (LF), and middle luteal (ML) phases of the menstrual cycle and different factors that may influence football performance. Methods To this end, 11 eumenorrheic sub-elite female football players underwent field tests to assess sprint speed, lower extremity power, repeated sprint ability, velocity on change of direction, and technical skills at each cycle phase. Results Performance during the 15-m change of direction ability test, 15-m ball dribbling test, squat jump height, total sprint time [sum of 7 sprints] and decrement score [(mean sprint time/best sprint time × 100) − 100], maximum and mean heart rate, and perceived exertion did not significantly differ among menstrual cycle phases. Conversely, the linear sprint velocity over 10, 20, 30-m distances was decreased in EF vs LF (10-, 20- and 30-m) and in ML vs LF (10- and 20-m) (p < 0.05). The 40-m sprint velocity did not change in the different menstrual cycle phases. Conclusion Overall, our study suggests that sex hormone fluctuations during the menstrual cycle are not associated with vertical jump, velocity on change of direction, and repeated sprint ability, but may influence linear sprint velocity over short distances (10, 20, and 30 m).

Evaluating the Effects of Consecutive Phases of Plyometric Jump Training on Athletic Performance in Male Soccer Players: The Effect of Training Frequency and Volume Manipulations.

Moran, J, Vali, N, Tallent, J, Howe, L, Clemente, FM, Chaabene, H, and Ramirez-Campillo, R. Evaluating the effects of consecutive phases of plyometric jump training on athletic performance in male soccer players: The effect of training frequency and volume manipulations. J Strength Cond Res 38(6): 1082-1089, 2024-This 14-week, 2-phase study aimed to determine the relative effects of 1 day or 2 days of volume-matched plyometric training on athletic performance (10- and 40-m sprints, change of direction [COD], and vertical jump [VJ]) in male soccer players (phase 1). The objective of phase 2 was to determine the relative effects of higher- and lower-volume plyometric training protocols in maintaining any previously attained increases in athletic performance from phase 1. A randomized parallel-group trial design was utilized. In phase 1, subjects ( n = 24; mean age: 19.5 ± 1.2 years; mean height: 179.7 ± 7.1 cm; mean weight: 69.8 ± 6.9 kg) were randomly allocated to 1 of 2 groups to receive either 1 day or 2 days of volume- and intensity-matched plyometric training for a 7-week period. For the second 7-week period (phase 2), half of each group was randomized into either a lower-volume or higher-volume plyometric training group. In phase 1, both the 1-day group and the 2-day group attained comparably significant ( p < 0.001) increases in performance in all fitness tests ranging from effect sizes (ESs) ( d ) of 0.4 (95% confidence interval: 0.11 to 0.70) for 10-m sprint to 1.51 (0.42-2.60) for VJ. There were no significant differences between the performance increases in the 2 groups. In phase 2, neither group increased or decreased performance, maintaining all previously attained increases with only trivial ESs observed (-0.02 [-0.58 to 0.53] to 0.11 [-0.38 to 0.61]). Increases in 10- and 40-m sprint speed, COD speed, and VJ height can be achieved and maintained with as little as 1 plyometric training session per week. Sessions can include 120 jumps to induce increases of the reported magnitudes, with 60 jumps to maintain these increases thereafter, in male soccer players.

The Relationship Between the Isometric Squat and Stretch Shortening Cycle Function and Sprint Acceleration Performance in Hurling Players.

Brady, CJ, Harrison, AJ, Flanagan, EP, Haff, GG, and Comyns, TM. The relationship between the isometric squat and stretch shortening cycle function and sprint acceleration performance in hurling players. J Strength Cond Res 38(6): e288-e298, 2024-The primary aim was to examine the relationship between sprint acceleration performance and the performance tests: isometric squat (ISqT), countermovement jump (CMJ), and reactive strength index (RSI). The secondary aim determined whether these tests could distinguish between sprint performance levels. Twenty-six male under-21 subjects completed the ISqT, with peak force (PF), relative PF, force at 100, 150, and 200 milliseconds (ms), and impulse (0-200 ms) measured. Jump height (JH) was calculated from the CMJ and RSI during the 10-5 repeated jump test. Subjects completed 3 × 30-m sprints with splits taken at 5, 10, 20, and 30 m. Pearson's product moment correlations were used to assess the relationships between measures, and independent samples t tests were used to determine whether differences existed in sprint ability of those in the top and bottom quartiles for force at 100 ms, CMJ, and RSI. Significant negative moderate correlations were reported between force at 100 ms and 0-5 m and 5-10 m, significant moderate and large negative correlations between CMJ and all splits and significant large correlations between RSI and splits over 5 m. Force at 100 ms distinguished between performance levels from 0 to 5 m, CMJ from 10 to 20 m, and RSI from 20 to 30 m; faster subjects produced significantly higher force, JHs, and RSI scores. Three principal components explaining 86.1% of the variation in the data set were identified: sprint times and stretch shortening cycle capabilities (33.3%), time-specific force (29.9%), and absolute and relative strength (22.8%).

Talent identification in soccer: The influence of technical, physical and maturity-related characteristics on a national selection process.

The present study examines the influence of technical, physical, and relative age characteristics on players selection success within the Scottish Performance School trials. Ninety adolescent players (81 males, 9 females; mean ± standard deviation: age = 11.3 ± 0.4 years, height = 149.6 ± 6.9 cm, mass 38.1 ± 4.7 kg) performed a battery of physical fitness (20m Sprint, CMJ, 5-0-5 agility test), anthropometric, and 8 small-sided games (SSG; 9v9) as part of a talent identification (TID) programme. Players technical (ball touches, time on the ball, high-speed releases) and locomotor activities (high-speed running distance, sprint distance, accelerations, and decelerations) were monitored using foot-mounted inertial measurements units during SSG's. The data was analysed using independent sample T-tests. Mann-Whitney U analyses were conducted to examine the differences between groups whose data was determined as being (non)parametric, with Cohen effect sizes applied. Successful players performed significantly better during physical tests (Effect size ± confidence limits: Left 5-0-5 = -0.89±0.13, Right 5-0-5 = -0.51±0.11), had significantly higher locomotor activities during SSG (high-intensity distance = 0.4±26.6, horizontal accelerations = 0.59±1.19) and significantly higher technical outputs during SSG (touches = 0.71±6.1, releases = 0.49±2.5, high-speed releases = 0.59±2.7, time on the ball = 0.52±3.4) compared to unsuccessful players. Successful players had significantly higher locomotor activities and technical outputs during SSG than their unsuccessful counterparts. Monitoring technical and locomotor activities during SSG may compliment or replace physical testing batteries for assessing TID processes in soccer.

Effects of Nordic versus Sprint Exercise Program in Prevention of Hamstring Injuries in Football Players

Background: Hamstring strain injuries (HSI) are frequent in football and other high-speed running sports. Nordic hamstring exercise (NHE) has been found to increase eccentric hamstring strength and decrease the risk of hamstring strain injury (HSI). Sprint exercise, which includes maximal eccentric contractions, is supposed to engage the hamstrings and prevent HSI. Objective: The aim of this randomized controlled trial was to compare the effectiveness of Nordic and sprint exercise programs in preventing hamstring injuries in football players. Methods: The study involved 26 male football players aged 18-25 years, who exercised regularly for 2-3 times a week in the preceding 3 months. They were randomly divided into two groups. One group received Nordic exercise and conventional treatment, while the other group received sprint training exercises and conventional treatment. The duration of the program was 6 weeks, with two 30-minute sessions per week. The evaluation was based on the 40m sprint test and active knee extension test, which were measured using a goniometer. The 40m sprint was timed, and the active knee extension test measured the range of motion. The results were analyzed based on these measurements. Results: The participants' average ages, heights, and weights were respectively 21.1538 1.91191, 1.74 0.029, and 74.8462 4.18275. Shapiro-Wilk test was applied showed data to be non-parametric distributed (P &lt; 0.05). Wilcoxon and Mann Whitney tests were used to analyze the difference between pre- and post-treatment scores in the experimental and control groups. which were found to significanlty improved in experimental group, while both groups found to be improved significantly in a pre-post analysis, p value &lt; 0.05. Conclusion: Both Nordic and sprint exercise programs were effective in reducing the risk of hamstring injuries. However, the Nordic exercise program showed significantly greater improvement in preventing HSI in football players.

SAQ training on sprint, change-of-direction speed, and agility in U-20 female football players.

The purpose of the study was to investigate the effects of an 8-week speed, agility, and quickness (SAQ) training on performance changes in linear sprint speed, change-of-direction (COD) speed, and reactive agility of U-20 female football players. Nineteen female football players randomly served as either experimental (n = 9) or control groups (n = 10). The players were tested for physical fitness tests: linear sprint speed including both short and long distances (5- and 10-m sprints without a ball and 20- and 30-m sprints with and without dribbling), COD speed (arrowhead agility test with and without dribbling a ball, Southeast Missouri [SEMO] agility test, and 22-m repeated slalom dribbling test), and reactive agility. Significant group × time interactions were observed for sprint over long distances and COD speed but not for short sprint and reactive agility performances. Paired t-tests revealed considerable improvements in all performances from the pre-test to post-test for the SAQ group, except for the arrowhead agility (left; p = .07). The control group only exhibited significant improvements in 10-m sprint performance after general football training. Eight weeks of SAQ training were effective at enhancing acceleration, maximum sprint speed, and agility performances amongst highly trained U-20 female football players.

Comparison of physical fitness and game demands between young female rugby sevens athletes in different sports development contexts

Aim: This study aimed to compare the physical and game demands among young women rugby sevens athletes inserted in a long-term athlete development process (LTAD) and selected to the national team. Methods: Twenty-four athletes were recruited in two different contexts: thirteen participants were inserted in the LTAD process (VSR) and eleven Brazilian athletes were selected for the youth national team (BRA). One-repetition-maximum tests, jumping performance, sprint times, and aerobic capacity determined the physical performance and GPS recorded the game demands in the national championship. T-tests for independent samples and Mann-Whitney were used to compare the groups, and effect size (ES) was presented using Cohen's d. Results: 10-m sprint time (p = 0.001; ES = 1.47), 30-m sprint time (p = 0.005; ES = 1.42), sprint distance (p = 0.030; ES = 1.14) and distance in zone 5 (p = 0.040; ES = 0.92) showed differences between groups, with better results in BRA. Moreover, VSR athletes covered greater distances in zone 1 while BRA had greater distances in zone 4, with moderate ES. The strength, power of lower limbs, and aerobic fitness variables did not present significant differences between the groups. However, VSR had the highest mean in squat jump and countermovement jump, with moderate ES. Conclusion: Speed in physical tests and game demands differentiated the groups, and these parameters are essential for selection for the national team. However, the LTAD process can bring physical

Comparison between backward, forward, and combined running training on performance of recreationally active young men

The study verified the effects of backward running training (BRT), forward running training (FRT), and combined backward/forward running training (BFRT), prescribed by Vpeak, on performance in 5-km running, countermovement jump, 20-m sprint, and the agility T-test, in thirty-three recreationally active young men. Thirty-three men (age 27.7 ± 4.8 years) were randomly assigned to one of three training groups (BRT; FRT; BFRT) and performed the following tests: 5-km running, vertical jump, 20-m sprint, agility performance, pre- and post-five weeks of running training. The normality of the data was verified by the Shapiro-Wilk test and the comparisons between groups and moments were performed by mixed ANOVA for repeated measures, followed by Bonferroni’s post hoc; the percentage of variation and the effect size (ES) were calculated. A significance level of P &lt; 0.05 was adopted. All groups improved 5-km (P = 0.01) performance at post-training. The Vpeak (P &lt; 0.01) and duration of the incremental test (P &lt; 0.01) increased significantly in all groups after training. The Vpeak_BR increased significantly in the BRT and BFRT groups. CMJ jump height increased significantly for the FRT (P &lt; 0.01) and BFRT (P &lt; 0.05) groups. In the agility T-test there was a significant moment effect (P &lt; 0.01) on the performance time. In conclusion, the inclusion of BRT sessions into FRT, prescribed based on Vpeak_BR and Vpeak_FR, leads to improvements in 5-km endurance running performance in recreationally active young men. Thus, it is suggested that BRT prescribed by Vpeak_BR could be more widely incorporated into FRT as a training method to obtain the same results in endurance performance as FRT alone.

Effects of Plyometric Training on Physical Fitness Attributes in Handball Players: A Systematic Review and Meta-Analysis.

This meta-analysis aimed to examine the effects of plyometric training on physical fitness attributes in handball players. A systematic literature search across PubMed, SCOPUS, SPORTDiscus, and Web of Science identified 20 studies with 563 players. Plyometric training showed significant medium-to-large effects on various attributes: countermovement jump with arms (ES = 1.84), countermovement jump (ES = 1.33), squat jump (ES = 1.17), and horizontal jump (ES = 0.83), ≤ 10-m linear sprint time (ES = -1.12), > 10-m linear sprint time (ES = -1.46), repeated sprint ability with change-of-direction time (ES = -1.53), agility (ES = -1.60), maximal strength (ES = 0.52), and force-velocity (muscle power) (ES = 1.13). No significant impact on balance was found. Subgroup analysis indicated more pronounced agility improvements in players ≤ 66.6 kg compared to > 66.6 kg (ES = -1.93 vs. -0.23, p = 0.014). Additionally, greater improvements were observed in linear sprint and repeat sprint ability when comparing training durations of > 8 weeks with those ≤ 8 weeks (ES = -2.30 to -2.89 vs. ES = -0.92 to -0.97). In conclusion, plyometric training effectively improves various physical fitness attributes, including jump performance, linear sprint ability, maximal strength, muscle power and agility.

Acute effects of caffeine supplementation on kinematics and kinetics of sprinting.

We investigated the acute effects of caffeine supplementation (6 mg･kg-1 ) on 60-m sprint performance and underlying components with a step-to-step ground reaction force measurement in 13 male sprinters. After the first round sprint as a control, caffeine supplementation-induced improvement in 60-m sprint times (7.811 s at the first versus 7.648 s at the second round, 2.05%) were greater compared with the placebo condition (7.769 s at the first versus 7.768 s at the second round, 0.02%). Using average values for every four steps, in the caffeine condition, higher running speed (all six step groups), higher step frequency (5th-16th and 21st-24th step groups), shorter support time (all the step groups except for 13th-16th step) and shorter braking time (9th-24th step groups) were found. Regarding ground reaction forces variables, greater braking mean force (13th-19th step group), propulsive mean force (1st-12th and 17th-20th step groups), and effective vertical mean force (9th-12th step group) were found in the caffeine condition. For the block clearance phase at the sprint start, push-off and reaction times did not change, while higher total anteroposterior mean force, average horizontal external power, and ratio of force were found in the caffeine condition. These results indicate that, compared with placebo, acute caffeine supplementation improved sprint performance regardless of sprint sections during the entire acceleration phase from the start through increases in step frequency with decreases in support time. Moreover, acute caffeine supplementation promoted increases in the propulsive mean force, resulting in the improvement of sprint performance.

Are the ground reaction forces altered by the curve and with the increasing sprinting velocity?

In 200- and 400-m races, 58% of the total distance to cover is in the curve. In the curve, the sprinting performance is decreased in comparison to the straight. However, the reasons for this decreased performance is not well understood. Thus, the aim of this study was to identify the kinetic parameters underpinning the sprinting performance in the curve in comparison to the straight. Nineteen experienced-to-elite curve specialists performed five sprints in the straight and in the curve (radius 41.58 m): 10, 15, 20, 30, and 40 m. The left and the right vertical, anterior-posterior, medial-lateral, and resultant ground reaction forces (respectively , , , and ), the associated impulses (respectively , , , and ) and thestance times of each side were averaged over each distance. In the curve, the time to cover the 40-m sprint was longer than in the straight (5.52 ± 0.25 vs. 5.47 ± 0.23 s, respectively). Additionally, the left and the right and were lower than in the straight while the left and the right increased, meaning that the was more medial. The left was also lower than in the straight while the left stance times increased to keep the left similar to the straight to maintain the subsequent swing time. Overall, the sprinting performance was reduced in the curve due to a reduction in the left and the right and , that were likely attributed to the concomitant increased to adopt a curvilinear motion.

Influence of Growth, Maturation, and Sex on Maximal Power, Force, and Velocity During Overground Sprinting.

Sudlow, A, Galantine, P, Del Sordo, G, Raymond, J-J, Dalleau, G, Peyrot, N, and Duché, P. Influence of growth, maturation, and sex on maximal power, force, and velocity during overground sprinting. J Strength Cond Res 38(3): 491-500, 2024-In pediatric populations maximal anaerobic power, force, and velocity capabilities are influenced by changes in body dimensions and muscle function. The aim of this study was to investigate the influences of growth, maturation, and sex on short-term anaerobic performance. One hundred forty children pre-, mid-, and postpeak height velocity performed two 30-m sprints concurrently measured using a radar device. Maximal power (Pmax), force (F0), and velocity (v0) were calculated from sprint velocity-time data and normalized using sex-specific, multiplicative, allometric models containing body mass, fat-free mass (FFM), or height, and chronological age. Absolute values for Pmax, F0, and v0 were higher with increasing maturity (p < 0.01; d ≥ 0.96), and boys had greater outputs than girls (p < 0.01; d ≥ 1.19). When Pmax and v0 were scaled all maturity-related and sex-related differences were removed. When F0 was scaled using models excluding age, all maturity-related differences were removed except for the least mature group (p < 0.05; d ≥ 0.88) and boys maintained higher values than girls (p < 0.05; d ≥ 0.92). All maturity-related and sex-related differences were removed when F0 was scaled using models including age. Maturity-related and sex-related variance in Pmax and v0 can be entirely explained when FFM, height, and chronological age are accounted for. Regarding F0, there seems to be a threshold after which the inclusion of age is no longer necessary to account for maturity-related differences. In young prepubertal children, the inclusion of age likely accounts for deficits in neuromuscular capacities and motor skills, which body dimensions cannot account for. Practitioners should focus on eliciting neural adaptations and enhancing motor coordination in prepubertal children to improve anaerobic performance during overground sprinting.

The Effectiveness of Physical Education Classes Through Collaborative Learning Methods for the Physical Development of 11th-Grade Students in Vietnam

Abstract Introduction. Collaborative Learning (CL) is a group learning method that involves mutual support and assistance among individual students to achieve learning goals. The purpose of this study is to assess the effectiveness of a 14-week Physical Education (PE) class using the CL method in enhancing the physical development of 11th-grade students. Material and Methods. Eighty healthy students were randomly selected and divided into two groups: the experimental group with 40 students applying the CL method in PE classes, and the control group with 40 students studying PE using conventional methods. In this study, five fitness tests were used such as a 30-s sit-up test, a 30-m sprint test, a 4 × 10-m shuttle run test, a standing long jump test, and a 5-min running field test. Results. After 14 weeks of experimentation, independent t-test results indicated a significant difference in the mean values between the experimental and control groups at the threshold of p &lt; 0.05. Paired t-test results for the mean values before and after the experiment in both groups also showed a difference, with the physical fitness growth rate of the experimental group being higher than that of the control group. Particularly, the control group exhibited a post-experiment value that had a negative significance. Conclusions. This demonstrates that the experimental results serve as an illustration, confirming the effectiveness of the CL method in high school PE classes. Teachers should enhance the use of CL in the future to achieve higher learning goals.