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THE LARGE VOLUME AND THREE-DIMENSIONAL SHAPE OF THE FLEXOR HALLUCIS LONGUS MUSCLE IN SPRINTERS AND DISTANCE RUNNERS
No full textWe investigated the anatomical characteristics of flexor hallucis longus (FHL) in high-level sprinters and distance runners. We recruited 14 sprinters, and 15 distance runners. The lower leg was scanned using magnetic resonance imaging. All scans were segmented then FHL’s 3-D shape was compared between groups using statistical shape modelling. In addition, we quantified muscle volume and mass, largest anatomical cross-sectional area, muscle length. Considering muscle volume, largest anatomical cross-sectional area and muscle length, we found no significant differences between sprinters and distance runners, and the shape of the muscle was also similar between groups. When compared to studies on non-runners and cadavers, runners in this study had larger FHL volume, which may implicate the role of FHL in running
PACING AND STROKE MECHANICS IN 400M FREESTYLE: A HIERARCHICAL GENERALIZED ADDITIVE MODEL ACROSS PERFORMANCE LEVELS
No full textThis study explores the relationship between stroke mechanics regulation and pacing optimization in the 400m freestyle across different performance levels. The analysis involves 127 trained to elite swimmers, divided into performance groups, using an IMU sensor to measure spatiotemporal parameters. A Hierarchical Generalized Additive Model identified trends and group-specific variations in speed, stroke rate, stroke length, and stroke smoothness (jerk cost). Results show higher-performing swimmers better adapt technique to pacing by balancing stroke rate and length. Models reveal group differences, especially in pacing management and efficient technical regulation among top swimmers. This study emphasizes developing technical skills for pacing to enhance 400m freestyle performance
MACHINE LEARNING AND DEEP LEARNING APPLICATIONS IN SPORTS BIOMECHANICAL ANALYSIS: A SYSTEMATIC SCOPING REVIEW OF PERFORMANCE ENHANCEMENT AND INJURY PREVENTION STRATEGIES
No full textAim: This scoping review systematically maps current trends in artificial intelligence applications for sports biomechanical analysis, examining performance enhancement and injury prevention utility, methodological approaches, implementation challenges, and ethical considerations. Methods: A comprehensive analysis synthesized evidence on AI methodologies applied to sports biomechanics across various contexts, including machine learning, neural networks, and deep learning approaches integrated with learning management systems. This review examined data collection modes, analytical approaches, and practical implementation in laboratory and field settings. Results: AI applications evolved from basic statistical modeling to sophisticated machine learning configurations, demonstrating superior performance in technique analysis (94% agreement with international judges), individualized training prescription (25% improvement over baseline), and injury risk forecasting (85% pre-competition accuracy). Computer vision technology achieved marker-based joint tracking accuracy within 15mm, while temporal modeling detected biomechanical changes 2.5 training sessions before injury emergence. Learning management systems enhanced knowledge translation, improving coach understanding (45% increase) and athlete adherence (3.4-fold higher). Primary challenges remain data standardization, field validation, model explainability, and integration into established coaching workflows. Conclusion: AI integration into sports biomechanical analysis represents an irreversible paradigm shift, enabling unprecedented capabilities for movement analysis and preservation in sport. Implementation barriers and ethical considerations regarding data ownership, privacy, and equitable access require addressing through interdisciplinary partnerships and technological innovation to extend sophisticated biomechanical analysis across all competitive levels
NO DIFFERENCES BETWEEN MALES AND FEMALES IN THE NEURAL CONTROL OF EXPLOSIVE CONTRACTIONS
No full textMales and females exhibit comparable explosive relative to maximal strength. Given the greater proportion of type I fibres area in female muscles, motor units discharge rate (MUDR) in explosive efforts may be higher to compensate for slower contractile properties. To verify this, 22 females and 12 males (20-34 y), performed 10 rapid isometric ankle dorsiflexors, while recording high-density electromyography from tibialis anterior. Relative rate of torque development (RTD) measures (normalised to maximal torque) in the first 150 ms from contraction onset were not different (P \u3e 0.07) between sexes, nor MUDR at the beginning of the explosive efforts (61 ± 15 vs. 67 ± 16 Hz; P = 0.23). Time to peak RTD was shorter in males (61 ± 12 vs. 74 ± 14 ms; P \u3c 0.01). Thus, despite faster torque kinetics in males, the control of rapid torque production does not differ between sexes
THE INFLUENCE OF PINCH HOLDS\u27 WIDTH ON THE MECHANICS AND MUSCULAR ACTIVITY CHARACTERISTICS OF THE PINCH TECHNIQUE FOR ADVANCED CLIMBERS
No full textThis study aims to explore the effects of pinch holds’ width on the mechanics and muscle activity characteristics of the pinch technique in sport climbing. 22 climbers completed maximum gripping or pinching biomechanic test of a jug hold and two pinch holds with different width. The resultant traction force, traction force components, the utilization ratio of traction forces and root mean square (RMS) amplitude of the electromyography (EMG) signals of upper limb muscles were collected. Compared to the jug, traction force decreased by 6%-19% when using the broad pinch and 31%-46% with the narrow pinch (all P \u3c 0.05). The RMS of the pectoralis major, biceps brachii, and latissimus dorsi showed the pattern: jug \u3e the broad pinch \u3e the narrow pinch (all P \u3c 0.05). Traction force utilization at the broad pinch was 21%-62% higher than at the narrow (all P \u3c 0.05). Holds’ width is a significant factor in the biomechanical characteristics of pinching technique for climbers
SIMULATING THE EFFECT OF MEASUREMENT ERROR ON STRIDE TIME DETRENDED FLUCTUATION ANALYSIS
No full textThe aim of this study was to investigate the sensitivity of running stride time detrended fluctuation analysis (DFA) to simulated noise and the impact of noise on reliability measures. Varying magnitudes of Gaussian and uniform noise were added to series of touchdown event timings from 11 runners. DFA-α were calculated for ground truth and simulated stride time series. Simulated series were paired and test-retest ICC estimates computed. The error in DFA-α increased with noise magnitude, with stride time series transitioning from persistent to anti-persistent behaviour for greater magnitudes of noise. However, median ICC estimates stayed above 0.95 for all standard deviations of noise investigated. Thus, measurement noise in touchdown event timings is unlikely an explanation for the reported differences in the reliability of stride time DFA-α
EFFECT OF HAMSTRING STRENGTH INTERVENTION ON LOWER EXTREMITY BIOMECHANICS OF SPRINTING
No full textThe purpose of this study was to examine the effects of hamstring strength intervention on the lower extremity biomechanics. Fourteen college students volunteered to participate in this study, and underwent three weekly sessions of hamstring strength intervention for eight weeks. Three-dimensional kinematic and kinetic data during a sprint test (40 m) were collected before and after the intervention. The hip flexion angle, knee flexion angle at touch down and peak knee flexion angle instant, and peak knee extension moment during stance phase showed significant decreases in the post-intervention test compared to the pre-intervention test. The hip and knee joints were more extended in stance phase after intervention. Hamstring strength intervention may reduce the risk of hamstring strains and other knee injuries
DIFFERENCES IN TRUNK AND HIP ISOKINETIC STRENGTH PERFORMANCE AMONG CHEERLEADERS WITH VARYING SOMERSAULT TECHNICAL LEVELS
No full text啦啦隊中的站立後空翻 (SBTS) 需要精確的速度控制和軀幹-臀部協調，並依靠特定肌肉的力量。雖然 SBTS 通常可以實現，但更高級的站立全空翻 (SF) 需要更大的力量。這項研究評估了 17 名啦啦隊在 3 種不同速度（軀幹：30-120°/s；臀部：60-300°/s）下的軀幹和臀部等速力量。參與者根據技能分組：僅 SBTS（NSF，n = 9）和同時進行 SBTS 和 SF（SF，n = 8）。雙向變異數分析顯示 SF 組的髖部屈曲峰值扭矩明顯較大（p \u3c .05）。髖部伸展的顯著交互作用顯示 NSF 中 300°/s 和 180°/s 時的扭矩下降（p \u3c .05），而在 SF 中沒有觀察到。研究結果強調了強大的髖屈肌和保持高速髖伸展對於空翻動作的重要性，為有針對性的啦啦隊訓練提供了指導
Estimation of the Ground Reaction Forces During Golf Swing Using Recurrent Neural Networks
No full textAccurate ground reaction force (GRF) measurement is essential for in-depth golf swing analysis, but force plates are costly and require complex installation. This study develops an AI-based GRF estimation method using a Bi-LSTM model. Motion capture and force plate data from 1,032 swings by 344 golfers were used to train the model, while data from 29 unseen golfers were reserved for validation to prevent overfitting. A total of 864 models were trained using cross-validation and grid search, with the best-performing model selected based on ICC. The model achieved high accuracy (ICC up to 0.983), particularly for lead foot vertical GRF. This approach provides a scalable, cost-effective solution for movement analysis, with potential applications beyond golf
IMMEDIATE EFFECT OF HANDLE USE ON A NEW SWIMMING STARTING BLOCK
No full textThe purpose of this study was to compare kinematic variables between the handle start (using a starting block equipped with handles) and the kick start (without a handle) in male competitive swimmers and assess the immediate effects of adopting the handle start. Eight high school swimmers participated. Each participant performed two trials for each start type after two practice trials. Hand-release time, block time, 15-m time, attitude angles, and horizontal velocity were measured using two video cameras. Paired two-sample t-tests and effect size analyses were conducted to compare these variables. The 15-m time was significantly longer in the handle-start group (p = 0.03), with no differences in other variables. Handle starts without prior practice are not recommended