Journal of Human Kinetics最新文献

This study examined the effects of a 10-week functional balance training program using unstable surfaces on dynamic postural control, lower-limb power, and technical shooting performance in adolescent male basketball players. Twenty-one participants were assigned to an experimental group (n = 11; age 16.14 ± 1.13 years) or a control group (n = 10; age 16.89 ± 1.34 years). Both groups trained three times per week over the intervention period. The experimental group completed additional neuromuscular exercises on unstable surfaces, while the control group performed traditional resistance-based routines. Pre- and post-intervention assessments included the Y-Balance Test (YBT), vertical jump height, and jump shooting accuracy (JSA). Statistically significant improvements in dynamic balance (p < 0.001, d = 1.84) and shooting efficiency (p < 0.001, d = 1.78) were observed in the experimental group. The control group also improved significantly in balance (p = 0.021, d = 0.87) and shooting accuracy (p = 0.014, d = 0.95), but to a lesser extent. Between-group comparisons demonstrated significant advantages for the experimental group in both the YBT (p = 0.007, d = 1.00) and JSA (p = 0.004, d = 1.07). No significant improvements were found in vertical jump performance in either group (p > 0.05). These findings suggest that incorporating functional balance training into basketball conditioning programs may enhance postural control and technical shooting execution, with a notable effect size, particularly in dynamic balance. The improvements in Y-Balance scores indicate enhanced sensorimotor control, although further research is needed to clarify the underlying neuromechanical mechanisms.

The purpose of this study was to differentiate the attack-defense performance at various playing positions between the top and bottom teams during the Tokyo Olympics men's basketball competition, and to determine the relationship between the attack-defense performance of various positions and the final competition rankings. The rank-sum ratio (RSR) was employed to describe the attack-defense abilities of a total of 144 male players from 12 participating teams, which were divided into three groups according to their playing positions, namely centers (n = 27), forwards (n = 58), and guards (n = 59). Additionally, the independent sample t-test and Spearman Rho Correlation analyses were conducted to evaluate the differences and relationships among the various variables, respectively, at a 0.05 level of significance. The results showed that there were significant differences in points (p = 0.003), the 2-point field goal made percentage (p = 0.035), and defensive rebounds (p = 0.004) at the guard position, and assists (p = 0.047) at the forward position between the top four and the bottom four teams. The attack-defense ranks of the guard position presented high positive correlations (p = 0.000, r = 0.876) with the final competition rankings, while the center (p = 0.017, r = 0.669) and forward positions (p = 0.036, r = 0.608) showed moderate positive correlations. These results may be considered by coaches and players to include targeted training to improve the overall strength of the team.

There is limited evidence of recording eye movements in real-time while performing specific motor tasks in team games in response to environmental stimuli. This study aimed to examine how elite basketball and volleyball athletes adopted strategies during agility tasks, based on the type of team sports and gender. A total of 60 skilled players from both sports (30 males and 30 females), aged 16-18 years, participated in this study. Agility variables were assessed using the "Five-Time Shuttle Run to Gates" test, based on the "stop and go" protocol. To determine variables of fixation and saccade eye movements during the agility task, a mobile eye-tracking system was employed. MANOVA showed statistically significant main effects of gender and the type of team sport on agility (for both factors, p < 0.001, η² _part > 0.14) and on the number of saccades (η² _part = 0.16, p = 0.002; η² _part = 0.10, p = 0.018). Additionally, gender affected the number of fixations (η² _part = 0.08, p = 0.037). Regression analysis was used to explore the correlation between oculomotor variables and agility, indicating that for female basketball players, the number of saccades (ß = 1.04, B = 0.10) and the average velocity of saccades (ß = 0.79, B = 0.02) were the primary factors explaining agility variability. However, for male basketball players, agility test outcomes were largely determined by the duration of saccadic movements (ß = 0.79, B = 0.02). The findings suggest that the oculomotor scanning strategy in agility tasks significantly impacts athletic performance, and is influenced by the type of team sports and gender.

The purpose of the study was to compare physiological and performance responses during surface and underwater fin swimming. Thirteen male, elite fin swimmers performed four repetitions of 50-m sprints using a monofin (4 x 50 m) either on surface (S) or underwater with apnea (U). Performance time and the number of lower body kicks were recorded during 4 x 50-m sprints. Lactate was evaluated before the start, after the second and the fourth sprint and five minutes into recovery. The heart rate was measured continuously and respiratory function was recorded before and after each condition. Performance time was shorter and kicking frequency was higher in U compared to S (17.73 ± 1.18 vs. 19.94 ± 1.41 s, 135 ± 18 vs. 121 ± 15 kicks∙min^-1, p < 0.05). Lactate concentration was no different between conditions. Forced expiratory volume in 1 s and peak expiratory flow were no different before and after the sprints and between conditions (p > 0.05). Forced vital capacity and maximal voluntary ventilation were increased after sprints under both conditions (p < 0.05). The heart rate was decreased in U compared to S during both sprints (167-177 vs. 183-185 b∙min^-1) and the recovery period (141-151 vs. 166-174 b∙min^-1). Underwater and surface repeated sprint swimming present maximal dynamic and physiological responses that should be considered during fin swimming training.

Fatigue has been considered a risk factor for sports injuries, modulating full-body jump-landing biomechanics. Biomechanical assessments of jump-landing manoeuvres are typically performed before and after short-term fatigue protocols, but changes during the protocol are often neglected. Therefore, this study investigated spike jump-landing strategy alterations during and following a short-term fatigue protocol in volleyball. Forty-three healthy, adult, male volleyball players participated in this study. Three-dimensional full-body kinematics were collected when performing spike jump-landings before, during and after a short-term fatigue protocol specific for volleyball. Full-body sagittal plane joint angles were calculated and analysed with curve analysis using one-way repeated measures ANOVA and post-hoc paired sample t-tests to investigate fatigue effects (p < 0.05). A significant main effect of fatigue was found for all kinematic variables (p = 0.015-0.041). More specifically, more pelvis-trunk flexion and less hip, knee, and ankle (dorsi-) flexion were observed during and after the protocol compared to baseline (p = 0.001-0.003). Moreover, less hip and knee flexion was observed during the protocol compared to after fatigue (p = 0.001-0.005). In conclusion, significant kinematic changes were found with fatigue, and these were somehow more pronounced during fatigue, possibly due to decreased attention towards the jump-landing task execution. A decision tree was provided to help researchers, coaches and/or clinicians in determining whether screenings should be better performed during or after fatigue, based on practical considerations.

Change of direction movements are highly relevant for performance in team sports. While bilateral movement patterns appear advantageous, research indicates unilateral dominance in cutting manoeuvres among handball athletes. This means, cutting manoeuvres in the direction of the throwing arm are executed faster than those against the direction of the throwing arm. The aim of this study was to evaluate whether this unilateral dominance stemmed from differences in physical capabilities. We predicted that the specific speed differences in cutting could be explained by lateral power differences. Thirty-two handball athletes completed lateral jump tests and a handball-specific change of direction test. Movement speed during the test was determined via video analysis. Participants showed significantly higher movement speed and significantly higher jump distances in the direction of the throwing arm. However, a significant interaction for both variables indicated that differences in the jump width could not fully explain the differences in movement speed. This likely indicates that the reasons of unilateral differences in cutting manoeuvres are not only based on physical capabilities. Coordinative-technical aspects or psychological variables should be investigated in further research as basis for an evidence-based training concept in educating the bilateral unpredictable abilities in handball players.

The purpose of the study was to investigate the effectiveness of the performance index (PI) in monitoring anaerobic endurance of adult competitive swimmers during a nine-week intervention. The study included 30 male competitive swimmers. Participants were allocated to an advanced or an intermediate group, taking into account their training experience and sport results. Each participant was tasked with swimming eight lengths of a 25-m pool at maximum speed and full commitment with front crawl and with 15-s rest intervals between subsequent laps at the start of the intervention (pre-test) and nine weeks later (post-test). The performance index determined by the average speeds in successive laps was analysed. No statistically significant differences were observed between the groups in the calculated performance index at the end of the training cycle. A repeated measures ANOVA revealed an interaction between TIME (a repeated factor) and GROUP (a fix factor) (F1.28 = 25.45, p < 0.0001, η² = 0.476). Swimmers from the intermediate group significantly improved their PI (p = 0.0002), while the advanced swimmers did not. Coaches could apply the methodology presented in this study to the specific requirements of their disciplines. The adaptability of the performance index method makes it a valuable tool for assessing anaerobic endurance among athletes of varying experience levels, though it does not serve as a means to directly enhance anaerobic endurance.

Application of virtual reality has gained traction as a promoting tool in rehabilitation techniques, particularly in the enhancement of postural balance. This study aimed to explore the effects of various virtual reality environments on the postural control of young adults. Twenty-five active collegiate students (14 females and 11 males) participated in this cross-sectional investigation. Participants experienced four distinct virtual environments: (1) a wall approaching at a constant speed, (2) a wall accelerating towards them, (3) a tilting wall, and (4) a wall that returns after tilting. Postural sway was assessed using a pedobarographic platform, and the center of pressure matrices was computed. A one-way repeated measures analysis of variance was conducted to analyze the postural sway metrics across the reference and the four experimental conditions. Significant alterations were detected in maximum sway excursion (p = 0.004), and sway variability (p < 0.001) in the anterior-posterior axis, as well as sway variability in the medial-lateral axis (p = 0.022). Pairwise comparisons indicated that the environments featuring the accelerating wall and the returning wall upon tilting produced the most significant changes. Conversely, maximum sway velocity and sway area variables did not exhibit significant changes in either direction. The findings suggest that virtual reality environments, particularly those simulating tilting or movement, considerably challenge postural control without inducing simulator sickness. Furthermore, virtual reality offers a cost-effective means to simulate realistic visual disturbances, which can be beneficial for designing balance training based on virtual reality like exergame therapies.

This study aimed to investigate the associations of bilateral deficit (BLD) during jumping with physical performance represented by linear sprints and changes of direction (CODs) in tennis players. Thirty-eight tennis players (10 females and 28 males) completed a test program that included three types of jumping tests to determine BLD, two types of linear sprint tests (10 m and 20 m) to assess sprint performance, and three types of COD tests (505COD, 5105COD, and T-test) to evaluate COD performance. The three types of jumping tests included countermovement jumps (CMJs), squat jumps (SJs), and horizontal countermovement jumps (HCMJs). The bilateral index (BI) in jump height (JH), flight time (FT), peak force (PF), peak power (PP), average power (AP), and the force impulse (FI) were then calculated to quantify BLD. Change of direction deficit (CODD) was calculated by subtracting linear sprint test time from COD test time. Results showed that the BI during the CMJ was positively correlated with the linear sprint index (1 correlation, r = 0.33, p = 0.045) and most COD indices (19 correlations, r = 0.32-0.40, p = 0.013-0.049). The BI during the SJ was positively correlated with linear sprint indices (2 correlations, r = 0.32-0.35, p = 0.033-0.049) and most COD indices (17 correlations, r = 0.32-0.44, p = 0.006-0.049). The BI during the HCMJ was positively correlated with COD indices (12 correlations, r = 0.32-0.41, p = 0.010-0.049). Conclusively, BLD during jumping is positively associated with linear sprint and COD performance in tennis players, indicating that lower limb BLD could serve as an index to optimize physical performance and training.

This study aimed to investigate the effect of eight weeks of high-intensity interval training (HIIT) plus L-arginine supplementation on performance of highly trained female handball players. Thirty-two female handball athletes (age: 20.69 ± 0.45 years, body height: 169.38 ± 0.57 cm, body mass: 66.49 ± 1.06 kg) were randomly assigned to a placebo (n = 8), a L-Arg (n = 8), a HIIT+placebo (n = 8) or a HIIT+L-Arg (n = 8) group. HIIT was performed 2 days/week for 8 weeks and consisted of running at 90 to 95% of maximum aerobic speed with 15 s of active recovery, with all training sessions performed on a handball court. The L-arginine supplementation was 0.1 g/kg on training days and 0.05 g/kg on rest days. Performance was assessed using a comprehensive battery of tests, including the 20-m sprint test, the T-agility test, the Cooper test, and the running-based anaerobic sprint test (RAST). Both high-intensity interval training (HIIT) and L-arginine (L-Arg) supplementation led to significant improvements in anaerobic power and 20-m sprint speed (p < 0.05). However, combining HIIT with L-Arg resulted in improvements solely in anaerobic power, without yielding any additional benefits compared to HIIT alone. Notably, all intervention groups (L-Arg, HIIT, and HIIT + L-Arg) experienced significant declines in agility performance (p < 0.05). None of the strategies improved performance during Cooper test. These findings suggest that L-Arg supplementation during HIIT does not confer additional performance benefits and may even exert detrimental effects. Therefore, HIIT alone appears to be sufficient for enhancing anaerobic capacity in highly trained female handball players, and the use of L-Arg supplementation may be unnecessary or counterproductive in this context.