Journal of Sports Science and Medicine最新文献

Present study aimed to compare the effects of SSIT intervention with varying rest distributions on hormonal, physiological, and performance adaptations in soccer players. Thirty-six players were randomly divided into three SSIT groups, each performing 4 sets of 6-10 repetitions of 6-second all-out running with rest intervals at ratios of 1:3, 1:6, and 1:9. Prior to and following the 7-week training period, aerobic fitness indices and anaerobic power were evaluated using a graded exercise test with a gas collection system and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring vertical jump, 20-m sprint, and T-test change of direction speed, Yo-Yo IR1 and maximal kicking distance. Hormonal status was also monitored by evaluating testosterone and cortisol levels. Following the 7-week training period, all SSIT interventions resulted in significant enhancements (p < 0.05) in soccer-related performance, physiological parameters, and hormonal adaptations, exhibiting effect sizes that ranged from small to large. Comparative analysis indicated that the 1:9 SSIT results in greater adaptive responses (p < 0.05) in the vertical jump, peak power, testosterone, and cortisol compared to the 1:3 SSIT group. By contrast, the 1:3 SSIT group induced more adaptive responses (p < 0.05) in the mean power output, maximum oxygen consumption (V̇O_2max), and Yo-Yo IR1 compared to the 1:9 SSIT group. Hence, for enhancing physical performance, especially vertical jump height, anaerobic peak power, and hormonal adaptations, the 1:9 SSIT ratio is preferable. Conversely, shorter rest intervals (specifically, the 1:3 SSIT ratio) are better suited for eliciting heightened adaptive responses in mean power output, V̇O_2max, and Yo-Yo IR1 over the 7-week training period among young male soccer players.

The aim of this study was two-fold: (i) to compare physical fitness adaptations following small-sided games (SSG) and running-based high-intensity interval training (HIIT), considering sex interactions; and (ii) to describe intra-individual variations of adaptations in both men and women developmental/trained soccer players over an 8-week randomized parallel study design involving 25 women and 27 men. Pre and post-intervention assessments included countermovement jump (CMJ), 10-meter linear sprint test, change-of-direction (COD) deficit, and final velocity at 30-15 Intermittent Fitness Test (VIFT). Significant interactions between time, groups and sex were found in 10-m sprint (F_1,48 = 6.042; p = 0.018; η_p² = 0.112). No significant interactions between time, groups and sex were found in CMJ (F F_1,48 = 0.609; p = 0.439; η_p² = 0.013), COD deficit (F F_1,48 = 2.718; p = 0.106; η_p² = 0.054) and VIFT (F F_1,48 = 1.141; p = 0.291; η_p² = 0.023). Significant interactions were found between time and sex in CMJ (F F_1,48 = 29.342; p < 0.001; η_p²= 0.379), 10-m sprint (F F_1,48 = 4.359; p = 0.042; η_p² = 0.083), COD deficit (F F_1,48 = 5.066; p = 0.029; η_p²= 0.095) and VIFT (F F_1,48 = 11.248; p = 0.002; η_p² = 0.190). In conclusion, this study suggests similar effects of HIIT in both sexes. However, for women, SSG may entail less efficacy and more inter-individual variability compared to men. Therefore, HIIT could potentially be a better solution for women, whereas both training approaches were equally effective in men.

Small-sided games (SSGs) are frequently utilized in training settings to elicit specific stimuli that can promote physical fitness adaptations over time. However, various task constraints, such as pitch dimensions, can significantly influence both the acute external and internal load responses. Thus, understanding the impact of different pitch dimensions on physical fitness adaptations is crucial. This study sought to compare the physical adaptations induced by an SSG-based program utilizing more elongated pitches (SSGlw2; length-to-width ratio: 2.0) versus less elongated pitches (SSGwl1; length-to-width ratio: 1.0) on the Yo-Yo intermittent recovery test level 1 (YYIRT), and 30-meter sprint. This study employed a randomized controlled design. Forty-eight male soccer players (16.4 ± 0.6 years) participated. These players were randomly allocated to two experimental groups (N = 16, SSGlw1; N = 16, SSGlw2) and underwent two weekly additional training sessions over an 8-week period, while a group of 16 players continued with their regular in-field sessions as a control group. Evaluations were conducted before and after the intervention period. Significant interactions time u group were observed in regards YYIRT (F = 15.857; p < 0.001; = 0.413) and 30-m sprint test (p < 0.001). Between-group differences on YYIRT were found in post-intervention (p < 0.001), on which SSGlw2 (p < 0.001) and SSGlw1 (p < 0.001) were significantly greater in comparison to control group. Additionally, between-group differences on 30-m sprint were found in post-intervention (p < 0.001), on which SSGlw2 was significantly better than SSGlw1 (p < 0.001) and control group (p < 0.001). Coaches are advised to prioritize the use of more elongated pitch sizes to promote adaptations in sprint performance, while still acknowledging that aerobic capacity improvements remain significant compared to other pitch shapes.

This study aimed to identify the optimal surface for sprint interval training to maximize transfer effects on physical performance measures on the grass pitch. Using a randomized controlled trial design, 40 collegiate female soccer players were equally assigned to three experimental groups performing short sprint interval training (SSIT: 4 sets of 10 repetitions with 5 seconds all-out running, with a 50-second recovery period between each effort and a 3-minute rest interval between sets) on SAND, GRASS, LAND, and a control group. Before and after a 7-week training period, participants underwent a series of field-based tests to evaluate countermovement jump (CMJ), 20-m linear sprint, Illinois change of direction (CoD) speed, Yo-Yo IR1, 2.4 km time trial, and maximal kicking distance (MKD) performance. A two-way analysis of variance with repeated measures was conducted on the data, along with Bonferroni post hoc testing. After the intervention, the control group did not show any changes, while the SAND, GRASS and LAND training groups demonstrated improvements (p = 0.001) in their performance as follows: CMJ (effect size [ES] = 1.21, 0.97, 0.64), 20-m linear sprint (ES = -0.81, -0.55, -0.41), Illinois CoD (ES = -0.72, -0.79, -0.41), Yo-Yo IR1 (ES = 1.86, 1.19, 1.12), 2.4 km time trail (ES = -0.82, -0.62, -0.49), and MKD (ES = 0.60, 0.90, 0.72), respectively. Comparative analysis of SAND, GRASS, and LAND revealed that performing SSIT on SAND results in a significantly greater gain in CMJ than LAND (p = 0.041). Analyzing individual responses to training interventions indicated that the training surface had a favorable influence on CMJ (SAND vs. LAND, p = 0.009), but on other variables no statistically significant (p > 0.05) differences were observed. Considering these findings, it is advised that strength and conditioning coaches use the SAND surface as the initial choice for SSIT sessions regarding greater gains (i.e., ES) in performance. This recommendation aims to facilitate more favorable transfer in physical fitness adaptation on a soccer grass pitch. In case of unavailability of SAND surface, GRASS surface would be a suitable alternative to enhance the physical fitness of collegiate female soccer players.

Percussive massage (PM) is an emerging recovery treatment despite the lack of research on its effects post-eccentric exercise (post-EE). This study investigated the effects of PM treatments (immediately, 24, 48, and 72 h post-EE) on the maximal isometric torque (MIT), range of motion (ROM), and an 11-point numerical rating scale (NRS) of soreness of the nondominant arm's biceps brachii from 24-72 h post-EE. Seventeen untrained, college-aged subjects performed 60 eccentric elbow flexion actions with their nondominant arms. Nine received 1 minute of PM, versus eight who rested quietly (control [CON]). In order, NRS, ROM, and MIT (relative to body mass) were collected pre-eccentric exercise (pre-EE) and after treatment (AT) at 24, 48, and 72 h post-EE. NRS was also collected before treatment (BT). Electromyographic (EMG) and mechanomyographic (MMG) amplitudes were collected during the MIT and normalized to pre-EE. There were no interactions for MIT, EMG, or MMG, but there were interactions for ROM and NRS. For ROM, the PM group had higher values than the CON 24-72 h by ~6-8°, a faster return to pre-EE (PM: 48 h, CON: 72 h), and exceeded their pre-EE at 72 h by ~4°. The groups' NRS values did not differ BT 24-72 h; however, the PM group lowered their NRS from BT to AT within every visit by ~1 point per visit, which resulted in them having lower values than the CON from 24-72 h by ~2-3 points. Additionally, the PM group returned their NRS to pre-EE faster than the CON (PM: BT 72 h, CON: never). In conclusion, PM treatments may improve ROM without affecting isometric strength or muscle activation 24-72 h post-EE. Although the PM treatments did not enhance the recovery from delayed onset muscle soreness until 72 h, they consistently provided immediate, temporary relief when used 24-72 h post-EE.

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.

Research on the external physical load on elite youth soccer players during the weekly training microcycle in competitive periods and official matches is limited. The aims of this study were twofold: a) investigate possible differences in external physical load (PL) across player positions in U17 elite youth soccer players during official matches; b) determine the weekly training to match physical load ratio (WTMLr) across player positions. The sample included 20 outfield players from an elite soccer academy (mean age 15.94 ± 0.25 years) playing in four positions: central defender (CD), full-back (FB), central midfielder (CM) and Striker (S). Data were collected during the spring in-season period for 17 official matches played in a 4-3-3 game format. Indicators of external physical load monitored were: total distance (TD); total distance in high-speed running (HSR; > 16.1 km.h^-1); total distance in sprint running (SPR; > 21.6 km.h^-1); and relative physical load intensity (%HSR). The WTMLr was calculated for TD, HSR, SPR and %HSR as the ratio of the average weekly sum of training PL to the average sum of PL in an official match for a given players' position. Collectively, the training intensity during a one-week microcycle (%HSR in WTMLr) achieved only 76 % of match demands. CD performed significantly lower in all measured indicators of external PL during the official match than all other positions (p < 0.05; g > 0.80) except for TD in S. S achieved significantly higher SPR during official matches compared to CD (p < 0.05; g > 0.80), CM, and FB (g > 0.80). In contrast, CD reported higher WTMLr (medium-large effect size) in HSR and SPR indicators than all other positions. CM performed significantly higher %HSR in WTMLr than S and FB (p < 0.05; g > 0.80). Results revealed insufficient training intensity relative to match demands and, at the same time, weekly training PL did not meet match demands (especially in HSR and SPR) for players across the different positions. Therefore, practitioners should select appropriate training methods (drills and games) to ensure sufficient training intensity (HSR and SR metrics) and consider using the WTMLr, which can be used to help optimise and individualise training PL for different player positions.

Torsional stiffness of athletic footwear plays a crucial role in preventing injury and improving sports performance. Yet, there is a lack of research focused on the biomechanical effect of torsional stiffness in badminton shoes. This study aimed to comprehensively investigate the influence of three different levels of torsional stiffness in badminton shoes on biomechanical characteristics, sports performance, and injury risk in badminton players. Fifteen male players, aged 22.8 ± 1.96 years, participated in the study, performing badminton-specific tasks, including forehand clear stroke [left foot (FCL) and right foot (FCR)], 45-degree sidestep cutting (45C), and consecutive vertical jumps (CVJ). The tasks were conducted wearing badminton shoes of torsional stiffness measured with Shore D hardness 50, 60, and 70 (referred to as 50D, 60D, and 70D, respectively). The primary biomechanical parameters included ankle, knee, and MTP joint kinematics, ankle and knee joint moments, peak ground reaction forces, joint range of motion (ROM), and stance time. A one-way repeated measures ANOVA was employed for normally distributed data and Friedman tests for non-normally distributed data. The 70D shoe exhibited the highest ankle dorsiflexion and lowest ankle inversion peak angles during 45C task. The 60D shoe showed significantly lower knee abduction angle and coronal motions compared to the 50D and 70D shoes. Increased torsional stiffness reduced stance time in the FCR task. No significant differences were observed in anterior-posterior and medial-lateral ground reaction forces (GRF). However, the 70D shoe demonstrated higher vertical GRF than the 50D shoe while performing the FCR task, particularly during 70% - 75% of stance. Findings from this study revealed the significant role of torsional stiffness in reducing injury risk and optimizing performance during badminton tasks, indicating that shoes with an intermediate level of stiffness (60D) could provide a beneficial balance between flexibility and stability. These findings may provide practical references in guiding future badminton shoe research and development. Further research is necessary to explore the long-term effects of altering stiffness, considering factors such as athletic levels and foot morphology, to understand of the influence of torsional stiffness on motion biomechanics and injury prevalence in badminton-specific tasks.

Despite the numerous scientific evidence on the topic, there is no clear and consistent answer that clarifies the true effects of beetroot juice (BJ) supplementation on different types of physical performance. This study examined whether an acute intake of BJ improves swimming performance, physiological variables of anaerobic metabolism, or subjective measures during high-intensity interval exercise with incomplete rest in competitive swimmers. Eighteen competitive swimmers (nine females and nine males) participated in this cross-over randomized, placebo-controlled, double-blind and counterbalanced study. In two trials, swimmers ingested BJ (70 mL, 6.4 mmol/400 mg NO3-) or placebo (PLA) (70 mL, 0.04 mmol/3 mg NO3-) three hours before a 2×6×100 m maximal effort with 40 seconds rest between repetitions and three minutes between blocks. The 100 m times showed no differences between groups (p > 0.05), but there was an interaction between block×repetition×condition (F₅ = 3.10; p = 0.046; ηp² = 0.54), indicating that the BJ group decreased the time of the sixth repetition of block2 compared to block1 (p = 0.01). Lactate concentration showed no differences between conditions (p > 0.05), but there was a main effect of block (ηp² = 0.60) and a block×repetition interaction (ηp² = 0.70), indicating higher values in block2 and increasing values between repetitions in block1. The subjective scales, perception of exertion (RPE) and Total Quality Recovery (TQR), showed no effects of condition (p > 0.05), but BJ swimmers had a greater TQR in the last repetitions of each block. In conclusion, a single dose of BJ did not enhance intermittent swimming performance or modified the physiological (lactate and heart rate) or subjective (RPE and TQR) variables; although there was a possible positive effect on the exercise tolerance at the end of effort.

This study aimed to analyze the effects of three off-season training programs on the aerobic capacity, countermovement jump (CMJ), and linear sprint performance of young male soccer players. The study employed a randomized multi-arm design, consisting of three experimental groups: i) a high-intensity interval training (HIIT) group; (ii) a plyometric jump training (PJT) group; and (iii) a HIIT+PJT group; and an inactive control group. Fifty-eight under-19 male soccer players (aged 17.6 ±0.6 years) were randomly assigned to participate in a 3-week offseason training program exclusively performing HIIT, PJT, or a combination of both, while the fourth group remained inactive. Players underwent assessments twice, using the Yo-Yo Intermittent Recovery Test - Level 1 (YYIRT), CMJ, and 30-meter linear sprint. Significant interactions between time and groups were found in CMJ (p<0.001), YYIRT (p<0.001), and 30-m sprint (p<0.001). Group*time interaction revealed that the control group was significantly different from HIIT (p<0.001), PJT (p<0.001), and HIIT+PJT (p<0.001) considering the CMJ. Moreover, the control group was significantly different from HIIT (p=0.037) in YYIRT. Finally, the control group was significantly different from HIIT (p=0.024), PJT (p<0.001), and HIIT+PJT (p=0.021) considering the 30-m sprint. In conclusion, off-season training programs are effective in significantly reducing declines in CMJ and sprint performance compared to maintaining training cessation. However, in the YYIRT, only HIIT seems to be significantly superior to maintaining inactivity. To mitigate aerobic performance declines, incorporating HIIT sessions twice weekly during the offseason is advisable. To enhance or maintain jump performance, integrating at least one session of PJT weekly is beneficial.