Drop jumps versus sled towing and their effects on repeated sprint ability in young basketball players

Background The aim of the investigation was to compare the occurrence of post-activation performance enhancement (PAPE) after drop jumps, or heavy sled towing, and the subsequent effect on repeated sprint ability (RSA). Methods Ten young basketball players (17 ± 1 yrs) performed, in randomized order, RSA test with changes of direction after a standardized warm up followed by drop jumps, heavy sled towing, or no exercise (control condition). Neuromuscular assessments composed of two maximal voluntary contractions of the knee extensors, peripheral nerve stimulation, and surface electromyography (EMG), responses were recorded before and immediately after the RSA. The EMG signal of leg muscles during sprinting were also recorded as well as the blood lactate concentration. Results The drop jumps improved the RSA mean time (P = 0.033), total time (P = 0.031), and slowest time (P = 0.029) compared to control condition, while heavy sled towing did not change RSA outcomes (P > 0.05). All conditions exhibited a decrease of doublet high frequency stimulation force (pre-post measurement) (P = 0.023) and voluntary activation (P = 0.041), evidencing the occurrence from peripheral and central components of fatigue after RSA, respectively, but no difference was evident between-conditions. There was a significantly greater EMG activity during sprints for the biceps femoris after drop jumps, only when compared to control condition (P = 0.013). Conclusion Repeated drop jumps were effective to induce PAPE in the form of RSA, while heavy sled towing had no effect on RSA performance in young basketball players. Furthermore, both conditioning activities exhibited similar levels of fatigue following the RSA protocol. Thus, drop jumps may be used as an alternative to induce PAPE and thus improve performance during sprints in young male basketball players.

Relationships between Strength and Step Frequency with Fatigue Index in Repeated Sprint Ability

Force−velocity profile (FVP) and repeated-sprint ability (RSA) tests are indicators of physical capacities in most team sport players. The purpose of this study was to examine the stride kinematics during a repeated-sprint ability (RSA) test and to analyze the relationship between Bosco’s force−velocity profile (FVP) and RSA performance in elite female field hockey players. Thirteen elite-female players performed both RSA (six 30 m maximal sprints) and jumping (CMJ weighted and body weight) tests. Sprinting time fatigue indexes during a 30 m RSA test were correlated with step frequency fatigue indexes (r > 0.7; p < 0.01). CMJ50 showed a large relationship with sprint time fatigue indexes. FV50 showed a very large relationship with sprint time fatigue indexes (r > 0.7; p < 0.01), and a large relationship with the step frequency fatigue indexes (r > 0.5; p < 0.05). This study highlighted two possible ways to improve fatigue indexes in RSA, with the aim of maximizing the distances covered at high-intensities during the matches: (a) strength training and (b) focusing on step frequency during speed training.

In Junior High School Boys, a Comparison Of Hollow Sprint and Acceleration Sprint Methods on the Sprinter 100 Meters

The purpose of the study. The purpose of this study was to describe the increase in extracurricular spint abilities of male students at SMP Negeri 03. The research method was this study using an experiment with a quasi-experimental type of research and the research pattern used in this study was a nonequivalent control group design. Materials and methods. This design involves two groups, namely the experimental group and the control group, and the time of the study was carried out in June 2021. The subjects of this research were 10 extracurricular students of SMP Negeri 03 Bangkinang, Kampar Regency. Results. The results of this study can be concluded that the results of the 100 meter sprint ability of male extracurricular students at SMP Negeri 03 Bangkinang Kampar Regency with an average sprint ability of 100 meters 0.933, thus it can be concluded that by using the hollow sprint method on acceleration can improve the ability to run 100 sprints. Conclusions. Based on the results of data analysis, description, testing of research results and discussion, conclusions can be drawn based on the results of calculations that have been carried out, a significant value of 1.080 1.054 is obtained. Thus, the hypothesis states that there is a significant difference between the hollow sprint and accelerating sprint exercises on the 100-meter running speed of male students of SMP Negeri 3 Bangkinang in the 2020/2021 academic year, which is acceptable.

The Relationship Between Repeated Sprint Performances and 50m and 100m Swimming Degrees of Swimmers

Aim: The aim of this study is to investigate the relationship between short distance swimming performance and repeated sprint ability in swimmers. Methods: 12 male swimmers between the ages of 14-18 from Denizli Pamukkale University Swimming Sports Club Performance team voluntarily participated at this study. Freestyle swimming time of the subjects was measured by using Casio stopwatch. 10x15-m, 50-m and 100-m freestyle swimming degrees of swimmers were recorded. The ideal sprint time (IS), the total sprint time (TS) and the performance decrement (PD) were determined after repeated sprint test (RST). Lactate levels were recorded at the end of each test. The Borg scale was used to determine the perceived difficulty level. For the statistical analysis Pearson’s correlation was used to determine the correlations between 50- m and100-m freestyle swimming time and swimming times obtained at the end of RST (IS, TS, PD). Results: Significant relationships were found between the 50-m and 100-m swimming performance (p<0.01). Significant correlations were found between the IS and the TS and the 50-m swim results (p<0.01) and also the 100-m swim results (p<0.05). Significant correlations were found between the 50-m lactate values and 100-m lactate values (p<0.05). Significant relationships were found between 10x15-m RST lactate values and 50-m lactate values (p<0.05). Moreover, strong relations were found between the 10x15-m RST lactate values and 100-m lactate values (p<0.01). Conclusion: This study has shown that repeated sprint ability as well as higher anaerobic capability as reflected by the short distance. Keywords: swimming, repeated sprint ability, short distance swimming performance

Effects of chronic betaine supplementation on performance in professional young soccer players during a competitive season: a double blind, randomized, placebo-controlled trial

Objective Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players. Methods Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. Results Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. Conclusions 14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.

The effect of whole body vibration on the sprint ability of Korean national bobsled and skeleton athletes

This study aims to find out whether whole body vibration has an effect on the sprint ability to shorten the time of bobsled-skeleton athletes. Seventeen bobsled-skeleton athletes (male = 11, female = 6) were recruited from Korea Winter Olympics National Team. Participants were randomly assigned to either a sprint immediately after whole body vibration or a sprint without whole body vibration protocol during two separate visits by a period of 3 months. To evaluate the effects of the sprint ability, measurements were performed 60-m sprint recorded test. In males, at the 45m (p<0.05) significant faster sprint section record after WBV more than Non-WBV. In females, at the 15m (p<0.05), 30m (p<0.01), 45m (p<0.05), and 60m (p<0.05) significant faster sprint section record after WBV more than Non-WBV. In males, at the 30m (p<0.05), 45m (p<0.05), and 50m (p<0.05) significant faster sprint cumulative record after WBV more than Non-WBV. In females, at the 15m (p<0.05), 30m (p<0.05), 45m (p<0.01), 50m (p<0.01), and 60m (p<0.01) significant faster sprint cumulative record after WBV more than Non-WBV. This study indicated that significant faster after WBV more than Non-WBV in males and females bobsled-skeleton athletes.

The Relationship Between Repeated Sprint Performances and 50m and 100m Swimming Degrees of Swimmers

The aim of this study is to investigate the relationship between short distance swimming performance and repeated sprint ability in swimmers. 12 male swimmers between the ages of 14-18 from Denizli Pamukkale University Swimming Sports Club Performance team voluntarily participated at this study. Freestyle swimming time of the subjects was measured by using Casio stopwatch. 10x15-m, 50-m and 100-m freestyle swimming degrees of swimmers were recorded. The ideal sprint time (IS), the total sprint time (TS) and the performance decrement (PD) were determined after repeated sprint test (RST). Lactate levels were recorded at the end of each test. The Borg scale was used to determine the perceived difficulty level. For the statistical analysis Pearson’s correlation was used to determine the correlations between 50- m and100-m freestyle swimming time and swimming times obtained at the end of RST (IS, TS, PD). Significant relationships were found between the 50-m and 100-m swimming performance (p<0.01). Significant correlations were found between the IS and the TS and the 50-m swim results (p<0.01) and also the 100-m swim results (p<0.05). Significant correlations were found between the 50-m lactate values and 100-m lactate values (p<0.05). Significant relationships were found between 10x15-m RST lactate values and 50-m lactate values (p<0.05). Moreover, strong relations were found between the 10x15-m RST lactate values and 100-m lactate values (p<0.01). In conclusion, this study has shown that repeated sprint ability as well as higher anaerobic capability as reflected by the short distance. Keywords: swimming, repeated sprint ability, short distance swimming performance