Journal of Sports Medicine and Physical Fitness最新文献

Background: Although cross-sectional evidence exists regarding the association between sport specialization and health outcomes, sport-specific, prospective research is lacking. The aim of this study was to determine the relationship between sport specialization status and in-season injury and illness risk in elite female adolescent soccer players.

Methods: 80 female youth soccer players (ages 13-18) from a local youth soccer organization underwent preseason evaluation of maximal aerobic capacity (VO2max) and sport specialization and provided self-reporting of daily training load (session-rating of perceived exertion), injury and illness for two four-month competitive soccer seasons. Mixed effects logistic regression models were used to predict individual injury and illness (yes/no) during the study period, using sport specialization, age, and training load as fixed effects and individual athlete as a random effect.

Results: Specialized (N.=46) athletes did not differ from non-specialized (N.=34) athletes with respect to age, preseason physical activity, VO2max or in-season training load (all P>0.05). 28 athletes participated in both years, representing 108 player-years. No differences were seen in the proportion of individuals from each group that reported an in-season injury (specialized = 25% vs. 20%, P=0.55) or illness (46% v 38%, P=0.41). After adjusting for age and training load, individual injuries (OR=0.86 [0.26, 2.8], P=0.81) and illnesses were not significantly predicted by specialization (OR=1.06 [0.45, 2.5], P=0.89).

Conclusions: After adjusting for age and training load, late sport specialization was not associated with in-season injury or illness risk in elite female soccer players.

Background: Exercise addiction (EA) is a maladaptive pattern of excessive exercise despite negative physical, psychological, and social consequences. The Expanded Exercise Addiction Inventory (EAI-3) was developed to improve the assessment of EA. This study validates the Hebrew version of the EAI-3 in Israel, where physical fitness is closely tied to national identity and military culture.

Methods: A sample of 367 recreational exercisers (140 men, 227 women; aged 18-45) completed the Hebrew EAI-3, the Exercise Dependence Scale-Revised (EDS-R), and the Eating Attitudes Test (EAT-26). Confirmatory factor analysis (CFA) and measurement invariance testing were conducted.

Results: CFA supported a two-factor structure (Health Relevance and Addiction Tendency). A 7-item version demonstrated superior psychometric properties compared to the original 8-item scale. Internal consistency was moderate (α=0.61), but McDonald's omega (ω=0.68) indicated better reliability. The EAI-3 showed strong convergent validity with the EDS-R (r=0.45) and concurrent validity with the EAT-26 (r=0.24). The 7-item version achieved scalar invariance across gender, allowing for meaningful comparisons.

Conclusions: The Hebrew EAI-3 is a valid tool for assessing risk of exercise addiction in Israeli exercisers. The 7-item version is recommended for clinical and research applications, particularly for gender-based analyses.

Introduction: Core stability is essential for maintaining postural alignment and preventing injuries during athletic activities. A growing body of literature suggests that structured core stability programs can reduce the risk of both upper and lower limb injuries across various sports. However, the evidence remains scattered and inconsistent, particularly regarding specific populations and sports contexts.

Evidence acquisition: This scoping review was conducted following the Joanna Briggs Institute (JBI) methodology and reported according to the PRISMA-ScR guidelines. A comprehensive literature search was carried out across MEDLINE (via PubMed), Cochrane Library, PEDro, Scopus, and grey literature databases. Studies were included if they investigated the impact of core stability training on injury prevention in athletic populations, using the PCC (Population, Concept, Context) framework. Data extraction focused on participant characteristics, interventions, outcomes, and conclusions.

Evidence synthesis: Five randomized controlled trials (RCTs) met the inclusion criteria. The studies involved athletes aged 8 to 58 years across six sports disciplines (soccer, Gaelic football, basketball, volleyball, gymnastics, and swimming). All included interventions demonstrated positive outcomes in reducing injury incidence, improving neuromuscular control, and enhancing dynamic stability. However, variability in training protocols and methodological quality limited cross-study comparability. Most interventions were low-cost, equipment-free, and feasible in both team and individual settings.

Conclusions: Core stability training shows strong potential as a preventive strategy in sports injury management. Despite the variability among existing studies, the consistent positive effects suggest the need for broader integration into routine athletic training. Future research should aim to standardize protocols and explore long-term efficacy across diverse athletic populations.

Background: Monitoring body composition is crucial for optimizing performance and preventing injuries in young athletes during a competitive season. This study evaluated changes in body composition and bioelectrical impedance vector analysis (BIVA) in 15 male U17 Italian national handball players (age: 16.44±0.60 years).

Methods: Bioelectrical parameters were analyzed across four time points: end of the season (T0), pre-season (T1), season onset (T2), and winter break (T3), using repeated measures mixed models, while Mahalanobis' tests track vector shifts and ellipse distances (D). Statistical significance was set at P<0.05.

Results: The vector significantly lengthened from T0 to T1 (D=1.95), then shortened from T1 to T2 (D=1.63) and T2 to T3 (D=0.88). Stature-adjusted resistance significantly decreased at T2 (262.9 Ω/m±26.1) compared to T1 (275.6 Ω/m±27.8) and at T3 (249.7 Ω/m±21.4) compared to T0 (269.7 Ω/m±27.9), T1, and T2. Stature-adjusted reactance significantly increased at T1 (39.00 Ω/m±3.7) compared to T0 (35.3 Ω/m±3.6) then decreased at T2 (36.2 Ω/m±3.2) and T3 (35.7 Ω/m±3.4) compared to T1. From T0 to T3, phase angle, total body water, and fat-free mass increased significantly from 7.4°±0.5 to 8.1±0.6°, 59.9±3.6% to 61.1±3.7%, and 82.0±4.5% to 84.0±5.1%, respectively.

Conclusions: Bioelectrical analysis effectively tracks hydration indices and training adaptations in young athletes, representing a valuable tool for managing performance and recovery.

Background: Monitoring tendon morphology and function can improve our understanding of how tendons adapt to chronic training, potentially supporting the maintenance of strength and endurance. Despite that explosive sports share similarities, they also differ in key factors like movement speed and reactivity, loading duration and direction, range of motion, and muscle contraction type. This study aimed to compare the patellar tendon morphology and mechanical characteristics among sprinters, long and high jumpers, gymnasts, and karate athletes.

Methods: Forty-one elite male athletes with national and international competition experience participated. Patellar tendon properties, knee extensor strength, power, and rate of force development during countermovement jumps were measured during the pre-competition training phase.

Results: Results indicated that patellar tendon length, cross-sectional area, stiffness, and Young's modulus were similar across these athletes (P>0.05), despite differences in body weight, height, body composition, force production, and power output during dynamic movements. However, significant differences in patellar tendon stress were observed, correlating strongly with maximal knee extension peak torque and peak power during the countermovement jump (r > 0.646, P<0.01).

Conclusions: These findings suggest that patellar tendon morphology and mechanical properties were largely consistent across different power athletes, but high tendon stress resulting from increased force production highlights the need for a balanced relationship between force development and tendon adaptation.

Background: Reduced hip joint mobility increases lumbar spine stress, leading to disorders. However, the impact of thoracic spine mobility on lumbar spine disorders remains unclear, as do sport-specific differences in thoracic mobility.

Methods: Participants were male athletes aged ≥18 years (26 baseball, 50 rugby, 20 handball, 33 gymnastics). Thoracic spine flexion, extension, and total ROM were measured using a Spinal Mouse, and rotation ROM using an inclinometer. Study 1 examined thoracic ROM differences among sports. Study 2 classified rugby players and gymnasts based on presence or absence of low back pain (LBP) in the past 6 months and compared thoracic ROM.

Results: In Study 1, thoracic flexion ROM was lower in handball than in baseball and rugby. Thoracic extension ROM was greatest in gymnastics. Total thoracic ROM was lowest in handball and highest in gymnastics. Thoracic rotation was greater in baseball than rugby or handball on both sides. In gymnastics, dominant-side rotation was greater than rugby, and non-dominant-side rotation was greater than rugby and handball. In Study 2, rugby players with LBP had reduced thoracic flexion ROM, while gymnasts with LBP had reduced total thoracic ROM.

Conclusions: This study found that thoracic spine ROM differs by sport and is decreased in athletes with LBP, suggesting thoracic ROM is important for treating LBP in athletes.

Background: Despite a substantial body of literature on identifying talent in outfield players, information on goalkeepers (GKs) is scarce due to the specialist demands associated with the position. The purpose of this study was to explore which qualities GK coaches perceive as important for talented youth soccer GKs.

Methods: This qualitative study used a pragmatic research paradigm. The sample consisted of eight GK coaches (mean age 50.12±9.33 years; mean experience 17.25±9.97 years) who were purposively recruited to participate in the study. A semi-structured interview guide was used to collect data, and a two-stage thematic analysis was employed to identify themes.

Results: Four themes and 10 sub-themes were constructed: technical (i.e. handling), physical (i.e. upper body strength and height), tactical (defensive organization, build-up play and decision-making) and psychosocial (i.e. bravery, coachability, communication and composure) attributes.

Conclusions: These findings may provide coaches with valuable information regarding the traits that potentially talented GKs should possess, which could guide training for talent development programs to increase their chances of being chosen for future opportunities.

Background: This study investigates the key variables influencing injury occurrence in elite-level female volleyball players. It aims to evaluate three hypotheses: (1) the quantification of workload using the "System Training Response" score provides a superior explanation and prediction of injury occurrence compared to traditional methods such as sum or mean; (2) both menses and external workload serve as primary variables that explain injury occurrence; and (3) non-linear models yield better explanatory and predictive capabilities for injury occurrence than linear models.

Methods: Nineteen elite female volleyball players were monitored throughout a 190-day competitive season, during which various training-related parameters were collected. These parameters included internal and external workload quantification and menses data. To analyze and predict injury occurrence, machine learning techniques were employed, with a particular emphasis on Random Forest models.

Results: The Random Forest model demonstrated superior performance in describing injury occurrence, achieving an area under the receiver operating characteristic curve of 0.87. Key variables identified as significant contributors to injury occurrence included the players' age, menses status, and the percentage of intense jumps executed. Furthermore, the cross-validation procedure conducted on a reserved portion of the dataset yielded positive results, with an area under the receiver operating characteristic curve of 0.74, indicating a good generalization performance of the model.

Conclusions: The findings of this study suggest that intense training prior to performance may increase the risk of injury, while older players appear to exhibit a lower risk of injury. These insights highlight the importance of tailored training strategies that consider both physiological factors and individual player profiles to mitigate injury risks in elite female volleyball athletes, including the presence or absence of menstruation with associated discomfort, which appears to be a relevant factor.

Background: This study examines how coaching strategies influence performance patterns in elite Italian football, comparing the possession-based "building-from-the-back" style with a direct approach.

Methods: Observational data from all 380 matches of the 2022-2023 Serie A season, sourced from a public online platform, were categorized by playing style based on goalkeeper distribution patterns.

Results: Teams favoring the "building-from-the-back" strategy (Group 1) achieved superior results compared to those adopting direct play (Group 2). On average, Group 1 earned more points (63.8±14.4 vs. 40.2±14.1, P<0.002), scored more goals (57.3±10.5 vs. 40.1±12.5, P=0.004), and conceded fewer (42.4±10.4 vs. 55.0±10.9, P=0.017). They also recorded a higher goal difference (+14.9 vs. -14.9, P=0.003), greater ball possession (53.1±4.3% vs. 46.9±5.0%, P=0.009), more shot-creating actions (906.6±128.4 vs. 777.9±133.2, P=0.041), and more goal-scoring actions (97.7±17.3 vs. 64.8±24.0, P=0.003). Logistic regression showed that teams using build-up play were 13.5 times more likely to qualify for European competitions (95% CI: 1.20-152.0), with six of the seven qualified teams adopting this style. Effect sizes across metrics were consistently large (Cohen's d: 0.94-1.65).

Conclusions: Possession-oriented teams outperformed direct-play teams in both offensive and defensive indicators, underscoring the strategic role of coaches in orchestrating effective build-up play. These descriptive findings highlight how tactical choices are strongly associated with measurable outcomes in elite Italian football, offering data-driven insights for coaching methodologies and future research.