The present study analyzed the kinematic changes under fatigue in highly trained adolescent swimmers during a 50-m all-out front cwal test. Twenty-four girls and fourteen boys aged 12–13 participated in the study. The movement of the hip rim was analyzed using a specialized inertial device equipped with a triaxial gyroscope and accelerometer to measure changes in angular velocity and acceleration. Between the first and second lengths of the pool, the following were observed: a significant (F1.36 = 63.6; p < 0.0001; η² = 0.64) increase (34%) in maximum pelvic angle, significant (F1,36 = 6.0; p = 0.0193; η² = 0.14;) increase (12.10%) in angular velocity in rotational motion around a vertical axis, and a significant (F1,36 = 11.29; p = 0.0018; η² = 0.24) increase (6.86%) in angular velocity in yaw rotation motion around the sagittal axis. Significant (F1,36 = 13.96; p = 0.0006; η² = 0.28) differences in maximum pelvic angle were observed for lap and side. As unfavourable changes in kinematics are already observed in the second half of the distance, it is therefore suspected that performing frequent high-intensity repetitions may lead to the perpetuation of unfavourable movement patterns. Taking this into account, coaches should limit maximum-speed swimming in adolescent athletes to short distances and an appropriate interval and use training methods to reduce asymmetric work such as training snorkels.

Study aim: The aim of the study was to investigate the variability and symmetry of upper limb physiological tremor in elite sport dancers under simulated competitive conditions. Material and methods: Eighteen elite dancers (9 males, 9 females; age:16.1 ± 2.3 years; training experience: 8 ± 2.1 years; body mass: 62.0 ± 10.4 kg; height: 169.8 ± 7.9cm) all members national team and finalists in Polish championship, participated in the study. The experimental protocol involved a two-phase simulated competition, during which participants performed five standard dances in both semifinal and final rounds. Tremor signals were recorded before and after simulation using tri-axial accelerometry in a standardized postural postition. Frequency-domain analysis was conducted to extract tremor amplitude (L) and frequency (F) in two specific bands: 2–5 Hz and 9–14 Hz. Repeated measures ANOVA was used to analyze the effects of condition (pre vs. post), limb side, and gender. Results: Post-simulation tremor amplitude in the 9–14 Hz range increased significantly ( p = 0.0003; η _p ² = 0.60), suggesting the presence of neuromuscular fatigue and possible increased recruitment of fast-twitch muscle fibers. A significant interaction between limb side and gender (p = 0.006; η _p ² = 0.384) revealed asymmetrical tremor only in male participants, with higher post-exercise values in the dominant arm. Conclusions: Physiological tremor may serve as a low-cost, non-invasive biomarker of neuromuscular fatigue and motor asymmetry in competitive dance. Its application could support individualized training monitoring, optimize fatigue management, and injury prevention strategies in sports requiring high motor precision.

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.

Background/Objectives: Sports tendinopathy management has traditionally focused on mechanical loading protocols, yet emerging evidence suggests metabolic factors significantly influence clinical outcomes and tissue adaptation responses. The aim was to systematically evaluate the impact of metabolic factors on sports tendinopathy outcomes and assess the effectiveness of advanced rehabilitation approaches that extend beyond traditional mechanical loading protocols. Methods: A comprehensive search across academic papers from Semantic Scholar corpus identified studies investigating metabolic influences and advanced rehabilitation strategies in sports tendinopathy. Inclusion criteria encompassed athletes and active individuals with chronic tendinopathy, interventions targeting metabolic factors or advanced rehabilitation techniques, and validated outcome measures. Risk of bias was assessed using RoB 2 for randomized trials and ROBINS-I for observational studies. Evidence certainty was evaluated using GRADE methodology. Results: Forty studies met inclusion criteria, comprising 5 randomized controlled trials, 9 systematic reviews, and 5 cohort studies. Metabolic syndrome significantly impaired eccentric exercise outcomes in Achilles tendinopathy (F[1,54] = 24.45, p < 0.001). Collagen-derived peptide supplementation combined with eccentric training demonstrated superior pain reduction at rest compared to exercise alone (p < 0.05). Advanced rehabilitation strategies including criteria-based progression, neuroplastic training, and staged loading protocols showed improvements in patient-reported outcomes and functional scores, with some approaches demonstrating superiority over traditional eccentric protocols. Conclusions: Metabolic factors negatively influence sports tendinopathy rehabilitation outcomes, while advanced rehabilitation approaches incorporating metabolic considerations show promise for enhancing treatment effectiveness. Integration of metabolic assessment and targeted interventions may optimize tendinopathy management beyond mechanical loading alone.

The aim of this study was to assess the effect of long-term use of technical tethered swimming on kinematics of front crawl swimming, and swimming performance. The experiment was attended by 19 girls Thirty-nine adolescent swimmers (19 girls and 20 boys, aged 13 years) participated in the study. The participants were randomly assigned to two groups. The experimental group received additional technical tethered swimming protocol. At this time, the control group performed standard technical training in free swimming. The study included an 8-week training cycle. Changes in swimming technique were assessed using a device equipped with a triaxial gyroscope and a triaxial accelerometer, with a particular focus on body roll and yaw rotationof the athletes. Significant changes were observed in yaw rotation (ω_maxY, ab_max) and body roll (A_maxR) variables. The study showed that a training protocol involving technical tethered swimming can positively affect front crawl kinematics in adolescent athletes when applied over the long term.