Journal of Sports Science and Medicine最新文献

Table tennis athletes are required to execute appropriate footwork moving to the best position to hit the ball, while the chasse-step and one-step are typically employed in table tennis. This study aims to examine the difference in joint angles, joint moments, joint contact forces, and activation of lower limb muscles during the stance of chasse-step and one-step. Eighteen male table tennis athletes volunteered to perform topspin forehand with chasse-step and one-step. An eight-camera motion capture system and instrumented force plate were used to record makers' trajectories and ground reaction force, which was then used to calculate the kinematics and kinetics with Inverse Kinematics and Inverse Dynamics in OpenSim. Surface electromyography signals were measured to validate the musculoskeletal OpenSim modeling. Hip flexion angle and moment increased in the backward swing phase during the stance of one-step. Knee extension of the chasse-step increased more during the forward swing phase. Hip contact force increased in the anterior-posterior direction of one-step and the chasse-step in the medial-lateral direction. Key findings suggest that the chasse-step may increase the quality of footwork performance and prepare the next step but shows higher injury risk in knee joints. While the one-step may have faster performance for scoring and high injury risk in hip joint. The information may provide implications for athletes and coaches to improve athletic performance and develop specific footwork training schemes to prevent potential injuries.

The purpose of this study was to analyze the effects of compensatory training on later-born basketball players, who had less match time compared to their peers, focusing on their physical fitness and skill development. A prospective cohort study compared three groups of male youth basketball players (ages 12-14). One group consisted of later-born players with a high volume of match play in competitive scenarios (lbHPT), while the other two groups had match play below the median of the teams. Among these two groups, one received compensatory training (lbLPTcomp), and the other did not (lbLPTreg). Players were evaluated at three time points: baseline, 3 months, and 6 months. The assessments measured aerobic capacity (using the Yo-Yo intermittent recovery test), 10-meter sprint performance, 5-0-5 change of direction (COD deficit), and performance on the basketball technical test (LSPT). The compensatory training consisted of two weekly sessions in which, after regular training, the later-born players participated in 2v2 or 3v3 small-sided games lasting 15 minutes per session. The results revealed that lbLPTcomp was significantly effective in reducing the differences with lbHPT, as no significant differences were observed between the two cohorts over the 6 months for any of the outcomes (p > 0.05). Additionally, lbLPTcomp performed significantly better than lbLPTreg post-6 months in the LSPT (p = 0.033) and COD deficit (p = 0.003). The lbLPTreg group was also significantly worse than lbHPT in the YYIRT (p = 0.022), LSPT (p = 0.036), and COD deficit (p = 0.005). No significant between-group differences were found in 10-m sprint after 6 months (p = 0.241), though lbHPT and lbLPTcomp improved significantly (both p < 0.001). In conclusion, while compensatory training like twice-weekly small-sided games may help later-born youth athletes with limited playtime, further research is needed before broad implementation.

This systematic review and meta-analysis examines the effects of strength training (ST) and plyometric training (PT) on vertical jump (VJ), linear sprint (LS), and change-of-direction speed (CODS) in female adolescent team sport athletes. Additionally, it explores potential moderator variables, such as programming variables and participant characteristics, that may influence these training effects. Eligibility criteria: Randomized controlled trials examining the effects of ST or PT interventions lasting ≥4 weeks on VJ, LS, or CODS in female adolescent team sport athletes (aged 10-19 years) were included. A systematic search was conducted in PubMed, Web of Science, Cochrane, Embase, and SPORTDiscus from inception to August 28, 2024. The risk of bias of the included studies was assessed using the latest version of the Cochrane risk-of-bias tool for randomized trials (ROB-2). Meta-analyses were performed in Stata15.0 using random-effects models. Subgroup analyses were conducted based on the participant characteristics (age, height, weight, and type of sports) and programming variables (duration, frequency, and total sessions). Twenty-six studies involving 705 female adolescent team sport athletes were included. Meta-analyses revealed that ST and PT exhibited significant (p < 0.05) and moderate to large effects on VJ (ST, ES: 0.74, moderate; PT, ES: 0.87, moderate), LS (ST, ES: -1.26, large; PT, ES: -1.23, large), and CODS (ST, ES: -1.16, moderate; PT, ES: -1.20, moderate). Subgroup analysis indicated that for ST, training protocols of ≥ 10 weeks, ≤ 2 sessions/week, or ≤ 20 sessions were more effective. ST also showed greater benefits for athletes > 15 years old (LS), ≥ 163 cm (LS, CODS), ≥ 63 kg, and handball players. For PT, protocols of > 9 weeks, > 14 sessions (VJ), or ≥ 18 sessions (CODS) were more effective, with handball players responding best to PT. The overall risk of bias of the included studies was judged as moderate. The certainty of evidence was rated as moderate to high based on the GRADE approach. Both ST and PT are effective in improving VJ, LS, and CODS in female adolescent team sport athletes. Longer duration, lower frequency, or fewer sessions of ST produce better effects. Older and more mature athletes are better adapted to ST, likely due to increased muscle mass, hormonal factors, and neuromuscular adaptations. Longer duration or more sessions of PT produce better effects. Handball players showed a greater response to both ST and PT than athletes of other sports, according to observed trends.

Various physical training programs are widely used to enhance vertical jump height, but their relative effectiveness remains debated. This systematic review and meta-analysis evaluate effectiveness of four training methods -weight resistance, plyometric, complex, and routine training- on vertical jump height. A comprehensive search of six databases (PubMed, ERIC, Google Scholar, Web of Science, EBSCOhost, and Scopus) identified relevant studies coded based on training type, modality, and outcome measures. Methodological quality and statistical analysis were assessed using PEDro scale and R (version 4.1.3) with the 'meta' package. Eight studies revealed that plyometric training and weight resistance exercise increased vertical jump by 5.2 cm (95% CI: 2.6, 7.7 cm; I² = 4.7%) and 9.9 cm (95% CI: 6.7, 13.5 cm; I² = 0.0%), while improved squat jump by 1.5 cm (95% CI: 0.2, 2.6 cm; I² = 0.0%) and 3.1 cm (95% CI: 0.2, 2.6 cm; I² = 16.9%) compared to routine training. Fifteen studies indicated that plyometric training, weight resistance exercise, and complex training increased countermovement jump by 2.0 cm (95% CI: 1.4, 3.7 cm; I² = 0.0%), 2.2 cm (95% CI: 1.4, 3.7 cm; I² = 0.0%), and 5.0 cm (95% CI: 2.5, 7.6 cm; I² = 0.0%) compared to routine training. Complex training was more effective than weight resistance (2.6 cm; 95% CI: 0.2, 5.5 cm) and plyometric training (2.9 cm; 95% CI: 0.2, 5.8 cm), with no significant difference between weight resistance and plyometric training (0.2 cm; 95% CI: -1.0, 2.0 cm). Heterogeneity was low for most comparisons (I² = 0.0% to 16.9%), indicating consistent results across different interventions. This meta-analysis demonstrates that plyometric, weight resistance, and complex training significantly improve vertical, squat, and countermovement jump performance. Weight resistance is effective for vertical and stationary vertical jumps, while complex training is most effective for countermovement jumps.

This study aimed to (1) determine the kinematics of the different body parts during the execution of one of the basic combinations of plays - a few selected strokes and the footwork used to combine them, and (2) evaluate the variation of these kinematics. The study included eight male advanced-level (polish national team) table tennis players (aged 22.7 ± 2.7 years). All of them were right-handed and presented an offensive style of play. Participants performed one task: performing a series of topspin strokes. Kinematic parameters were measured using the MR3 myoMuscle Master Edition system. The movement of the playing hand was used to assess specific cycle events. Angular values and velocities of the body segments and maximal linear velocities of the playing hand were calculated. The basic statistics were applied. Quartile coefficients of variation were used to assess the interindividual variability. The research made it possible to determine the kinematics of the strokes used in the combination of plays in table tennis. The essential elements of coordination of movements during the combination of three topspin strokes were indicated. Players make strokes during a series of plays at high frequency and velocity (up to several hundred degrees/s at some joints), reducing the ranges of motion in specific body segments, which were observed to be smaller (even up to several dozen degrees) than the analogous ranges reported in the literature for single strokes. This seems to be a significant note to players and coaches in table tennis. In addition, the players execute the stroke slightly differently than in single strokes, which is caused by the need to combine the striking movement with footwork and quickly position themselves for subsequent hits. The players also used different, variable execution patterns (different angles - settings in the joints), although the effect - in the form of the maximum velocity of the playing hand - was very similar. This can be considered a manifestation of a phenomenon called "functional movement variability," which means that athletes adjust their movements using different movement patterns but achieve similar results regarding maximum linear hand speed. This highlights the importance of the individualisation process in table tennis.

Dynamic stretching (DS) uses a controlled movement through the range of motion (ROM) of the active joint(s) by contracting the agonist muscles without being held in an end position. In contrast, ballistic stretching (BS) typically uses uncontrolled movements of a higher velocity with bouncing actions. However, BS is often considered to be a form of DS. When considered together, DS and BS reportedly increase flexibility, evidenced by single- and multiple-joint ROM improvements and other measurements. However, a meta-analysis with subgroup analyses revealing the acute effects of DS and BS on flexibility in detail, independently of other stretching methods, has yet to be conducted. The purpose of this meta-analysis was to investigate the acute effects of DS and BS on flexibility in healthy participants. The PubMed, Web of Science, and Scopus databases were searched for eligible papers published before September 9, 2024; 17 papers were included in the meta-analysis. The main meta-analysis was performed with a random-effect model, and subgroup analyses were performed to examine the effects of age (young vs. middle-aged and older), sex (male vs. mixed sex), stretching methods (DS vs. BS), stretched muscles (hamstrings vs. plantar flexors vs. multiple muscles), and flexibility outcomes (single-joint ROM vs. straight-leg raise test vs. sit-and-reach test). A small increase in flexibility was found following DS and BS (considered together) (effect size = 0.372, Z = 3.936, 95% confidence interval = 0.187-0.557, p < 0.001, I² = 27%). Subgroup analyses revealed no significant differences between age (p = 0.24), sex (p = 0.76), stretching method (p = 0.83), stretched muscle (p = 0.20), or flexibility outcome (p = 0.34) groups. Our results suggest that DS and BS effectively provide acute, small-magnitude improvements in flexibility that are not significantly affected by individual characteristics, stretching methods, stretched muscles, or flexibility outcomes.

Prior studies have examined return-to-play (RTP) rates and performance outcomes following meniscus surgery in professional basketball players but have largely focused on earlier eras. With advancements in surgical techniques, rehabilitation, and player management strategies, updated insights into postoperative outcomes are needed. We hypothesized that National Basketball Association (NBA) players would demonstrate a higher return-to-play (RTP) rate than the ~80% reported in 2010, with short-term performance declines but recovery by the second postoperative season. We also evaluated the impact of age, body mass index (BMI), and position on outcomes. NBA players who sustained isolated meniscal tears and underwent surgery between 2010 and 2023 were identified through public databases. Performance metrics-including games played, minutes per game (MPG), player efficiency rating (PER), and distance covered per game-were assessed preoperatively and at one and two years postoperatively. Multivariable linear regression analyzed associations between age, BMI, position, and outcomes. Of 47 eligible players, 43 (90.7%) returned to NBA play. Players missed a median of 17 ± 34 games postoperatively and continued their careers for an average of 4.7 ± 3.4 seasons. The percentage of games played per season significantly declined at one (60.9%, p < 0.001) and two years (64.2%, p < 0.01) postoperatively versus pre-injury (79%), a novel finding. MPG and PER declined at one year (22.3 vs. 26.0, p = 0.02; 14.6 vs. 16.4, p = 0.04) but recovered by year two (23.8 MPG, 15.8 PER; both p > 0.1). Older age correlated with reduced games played, MPG, and PER. BMI and position had no significant impact. NBA players demonstrate high RTP rates after meniscus surgery. While playing time and efficiency recover by year two, reduced availability persists, likely reflecting ongoing workload management strategies.

Stretching the antagonist muscle to enhance agonist performance has gained considerable attention. However, most studies have focused on one stretching duration. Hence, the aim of this study was to compare varying durations (40-, 80-, and 120-seconds) of antagonist (dorsiflexors) static stretching (SS) on agonist (plantar flexors: PF) muscle performance. In this randomized crossover study, 16 participants (six females) underwent four sessions (40-, 80-, 120-s dorsiflexors SS and control), with pre- and post-intervention measurements of slow (60⁰/s) and fast (240⁰/s) PF isokinetic, isometric peak torque, total work, stiff leg drop jump (SDJ) performance (height, reactive strength index (RSI) and peak power), and tibialis anterior and soleus electromyography (EMG). Dorsiflexors SS protocol involved 1x40-s (40-s), 2x40-s (80-s), and 3x40-s (120-s). There were no significant pre- to post-intervention changes in any parameter. A main effect for time demonstrated an overall decrease in fast (p < 0.0001, 5.9%, d = 0.24) and slow (p = 0.05, 6.6%, d = 0.24) isokinetic peak torque, total work (p = 0.02, 5.1%, d = 0.20) and all SDJ measures (SDJ height: p = 0.02, 2.7%, d = 0.15, RSI: p < 0.0001, 5.9%, d = 0.23, peak power: p = 0.002, 4.4%, d = 0.22). Soleus EMG decreased from pre- to post-SS after 120-s in both isometric (p = 0.002, 13.6%, d = 0.73) and slow isokinetic (p = 0.002, 12.3%, d = 0.91) peak torque as well as 80-s with slow isokinetic peak torque (p = 0.02, 6.6%, d = 0.75). In summary, different durations of dorsiflexors SS (40-s, 80-s, 120-s) did not significantly influence PF performance. However, deficits associated with a main effect for time suggested possible testing effects as detected with the control condition.

The effect of plyometric jump training on children's jump and sprint performance remains unclear. To explore the effects of PJT on jump and sprint performance in children and to further analyze the influence of participant characteristics and training variables. A literature search was conducted in the PubMed, Web of Science, and SPORTDiscus databases. The included studies (n = 17) involved 587 children, with study sample sizes ranging from 9 to 44 participants. Overall, PJT improved children's vertical jump performance involving squat jump and countermovement jump (ES = 0.78, 95% confidence interval [CI] = 0.41-1.16, I² = 63%, p < 0.01; n = 474), standing long jump performance (ES = 0.56, CI = 0.3-0.83, I² = 26%, p < 0.0001; n = 414), and sprint performance involving 5 m to 30 m distances (ES = -0.41, CI = -0.61 to -0.22, I² = 0%, p < 0.01; n = 424). Subgroup analysis showed non-tapering strategies (ES = 0.92, n = 88) resulted in significant difference than tapering strategies (ES = 0.37, n = 336 np = 0.01). Meta-regression showed a positive correlation between the total number of training sessions and standing long jump performance improvement (p = 0.03). Two studies have a high risk of bias (RoB), and 15 studies have a moderate RoB (some concerns). The GRADE assessment indicated a very low to low robustness of the evidence. In conclusion, PJT can improve children's jump and sprint performance. Increasing the number of training sessions may lead to better standing long jump results. However, the low to very-low robustness of the currently available evidence precludes recommendations regarding PJT for improving children's neuromuscular performance.

Effective decision making and communication are essential skills for sports officials, who frequently report experiencing considerable stress across various sports. This study evaluated the impact of a stress management program on elite volleyball referees. The intervention aimed to reduce stress and anxiety while enhancing coping strategies. Thirty-eight referees (24 males, 14 females) participated in a randomized intervention guided by two experienced applied sport psychologists. Stress and physiological measures were assessed before and after officiating. Anxiety and officiating-related stress were evaluated using the State-Trait-Anxiety Inventory (STAI) and an adapted version of the Basketball Officials Source of Stress Survey (BOSSS-d), respectively. Cardiac responses, including heart rate (HR) and heart rate variability (HRV), were monitored during games. The program's effectiveness was assessed using the Inventory of Quality Sport Psychological Support (QS17). Although the pre- and post-intervention comparisons did not reveal significant changes in anxiety, reported sources of officiating-related stress, or cardiac responses, findings from the QS17 indicated potential benefits of the stress management program for elite volleyball referees, highlighting avenues for sport psychological support and interventions. Future research, particularly longitudinal studies, is needed to further explore referees' stress experiences during officiating.