Sports Biomechanics最新文献

The study aimed to investigate the effects of accumulated pitching counts on lower body neuromuscular fatigue (NMF) and pitching velocity. Twelve first-level collegiate baseball pitchers completed seven simulated innings (a total of 105 pitches), during which data on ball speed, countermovement jump (CMJ), and rate of perceived exertion (RPE) were collected. Ball speed did not show a significant difference over time (F_7,77 = 2.14; p = 0.57; η² = 0.16). Except for the modified reactive strength index (mRSI) (F_7,77 = 0.14, p = 0.94; η² = 0.01), all other CMJ parameters showed significant differences (e.g. eccentric rate of force development: F_7,77 = 17.44; p < 0.01; η² = 0.53; concentric impulse: F_7,77 = 9.66; p < 0.01; η² = 0.46). RPE showed a significant difference over time (F_7,77 = 52.86; p < 0.01; η² = 0.82) with a large effect size. Accumulated pitch counts caused lower body NMF in pitchers, while ball speed remained stable. Coaches should actively monitor pitcher conditions after completing the fifth inning (75 pitches), as ball speed may not be a reliable indicator of fatigue.

The study aimed to investigate the effects of different lengths of kinesiology tape (KT) on multi-segment foot biomechanical variables in individuals with chronic ankle instability (CAI). Kinematic and kinetic data were collected using a ten-camera Vicon motion capture system (200 Hz) and a force plate (1000 Hz). Twenty participants with CAI ran under three different conditions: no KT (NT), short KT (ST), and long KT (LT). A five-segment foot model was used, which has 8 degrees of freedom. The results indicated that CAI individuals running with KT might decrease the subtalar eversion angle and Chopart oblique angle during the stance phase. Differences in joint moments were observed at the ankle and subtalar joints during the running stance phase, with smaller ankle plantarflexion and inversion subtalar joint moments in the LT condition compared to the NT and ST conditions. Furthermore, LT was found to decrease the ankle ligament force and increased the force of lateral gastrocnemius muscle, soleus, peroneus longus, and peroneus brevis in individuals with CAI during the stance phase. These findings suggest that KT might reduce ankle ligament force and the risk of ankle sprains in individuals with CAI during running.

Body roll during front crawl swimming refers to spinal rotation along the longitudinal axis. It is typically evaluated at the shoulders and pelvis; however, the middle and lower thoracic and lumbar spine are overlooked. Therefore, we aimed to investigate the differences in rotation angles and peak timing across the upper (shoulder roll), middle and lower thoracic spine, lumbar spine, and pelvis (hip roll) during front crawl swimming. This study included 16 healthy swimmers. Participant had five inertial measurement units attached to the spinous processes and performed a 50 m front crawl swim. We measured and compared peak rotation angle and timing on the breathing side across the spinal segments. The upper thoracic spine (67.5 ± 13.6°) exhibited the greatest rotation, followed by the middle thoracic (55.2 ± 13.6°), which exceeded the lower thoracic (46.1 ± 12.2°), lumbar spine (46.3 ± 11.7°), and pelvis (46.5 ± 9.0°). No significant differences were found among angles of lower thoracic spine, lumbar spine, and pelvis, nor in peak timing across all segments. A significant positive correlation was observed between thoracic torsion and upper thoracic rotation angles. Study findings highlighted the importance of evaluating the middle thoracic spine along with shoulder and hip roll.

The importance of accelerating from a standstill is crucial in dynamic wheelchair sports, as it is closely tied to the ability to generate and apply significant power and net horizontal propulsion force. Assessing and quantifying para-athletes' physical capabilities could enhance training to performance transition. This study aimed to propose a field method for quantifying total wheelchair propulsion forces and output power, while exploring the usability of the 1080 Motion Sprint. Five para-athletes from the national French wheelchair racing team and seven wheelchair tennis players from the national French team participated. Unloaded and resisted sprints of 50 m and 20 m were performed. Mono-exponential velocity function was deduced using photocells, IMUs and the 1080 Motion Sprint velocity-time raw data. Net horizontal propulsion force was estimated from Newton's second law and considered the loads applied by the 1080 Motion Sprint, rolling resistance and aerodynamic drag. While no significant difference was observed between conditions for theoretical maximal force and maximum power developed, variations were evident in estimated power output and mechanical variables from force-velocity relationships, contingent on the athlete's classification and sport speciality. The developed protocol can be used by trainers to assess physical capacities during training sessions, guiding subsequent training.

Short-track speed skating is an incredibly precise sport, where even the smallest technical or physiological adjustment can profoundly impact performance, underscoring the importance of its study for achieving success. This study aims to identify short-track speed skating performance factors and quantify their impacts on athletes' performances. Twenty-nine short-track speed skaters (16 males and 13 females), with two different skill levels (National Elite and Junior Elite athletes), participated in this study. Movella IMU Link suits and Python scripts were employed to record and analyse one on-ice high-speed trial per athlete, focusing on lower body kinematics. From an initial pool of 535 tested factors, Pearson's product moment correlations and stepwise multiple linear regression identified seven significantly associated with lap time, with notable differences between sex and skill levels. Results revealed that inter-foot spacing and pelvic height, which are actionable by athletes, could each contribute to a gain of up to 0.51 seconds per lap if improved by 10 cm. For an average lap on a 500 m race, this means a 5.2%-time improvement. This research enhances the understanding of short-track speed skating performances by identifying factors that can improve lap times, offering practical implications for coaching strategies and athlete training programs.

The objective of this study was to compare joint angles and spatiotemporal variables between male and female ice hockey players during skating slap shots. Thirty-nine collegiate players (25 men, 14 women) participated. Kinematic data were collected using a Xsens 17-inertial measurement system. Key variables included joint angles for the trunk, upper, and lower extremities, as well as temporal measures for shot execution time, and the backswing, downswing, and follow-through phases. Statistical Parametric Mapping (SPM) was applied to analyse sex-based differences in joint kinematics. Temporal data were compared using two-way ANOVAs. Results indicated that males exhibited longer backswing and downswing phases, contributing to longer overall shot execution times. Males also demonstrated greater trunk flexion and lead shoulder flexion, while females showed more lead shoulder abduction, elbow flexion, and trail wrist extension during the backswing and downswing phases. These findings highlight the influence of anatomical and strength differences on slap shot mechanics. Considering sex-specific biomechanical differences in the development of training regimens and equipment design may enhance performance and development in ice hockey for all.

In Acrobatic Gymnastics, base and top gymnasts collaborate to perform partner-assisted flight. According to the literature, individuals engaged in pair/group tasks influence each other's movements to achieve a common goal. This study investigates similarity, time delay and relationship between base and top movements. It also examines distinct time frames-the motion until take-off versus until the end of the rotation, task difficulty and experience level. Eleven pairs performed two pair tasks in laboratory settings and were divided into less and more experienced groups. Cross-correlation (to assess movement similarity and time delay) and Granger causality (to evaluate mutual influence) were applied to the resultant centre of mass position of both gymnasts. The effects of time frame, task difficulty and experience level were analysed. Cross-correlation results show very high correlation coefficients (.98), with no effects from experience and task difficulty. Granger causality results indicate variations in predictive behaviour across conditions, particularly concerning the time frame and the effect of the task for the top gymnast, but did not provide evidence of causality. In conclusion, gymnasts perform highly similar and synchronised motion, with no clear evidence of direct influence, regardless of task difficulty or experience level.

A key motion in developing clubhead speed (CHS) during a golf swing is wrist cocking and uncocking on the swing plane. This study aimed to investigate how the morphological, temporal, and kinematic characteristics of drives performed by 84 elite male golfers differ among four distinct wrist release styles (WRS), classified based on the timing of uncocking and the shape of the on-plane wrist angular velocity pattern: Delayed Release 1 and 2 (DR1 and DR2), Early Release (ER), and Recocking (RC). Significant (p < .05) inter-style differences were observed in peak on-plane wrist uncocking velocity, transition and early downswing phase times, directions of the swing plane and hand motion plane, off-plane motions of the hand centre and clubhead, and the transition sequence. The DR styles generally showed larger uncocking velocities, longer transition and shorter early downswing phases, along with a complete proximal-to-distal sequential transition compared to the ER/RC styles. Styles with a prominent negative acceleration phase in the wrist angular velocity (DR1 and RC) exhibited relatively larger off-plane shallowing motions. CHS, however, did not show significant inter-style difference. The WRS reflects variations in backswing pattern (body- vs. arm-driven) and the degree of off-plane shallowing motions of the hands and club.

Collar height is a distinctive feature of court-sport footwear, yet its biomechanical effects remain underexplored. This study compared the effect of low-cut and high-cut footwear on lower-limb biomechanics during straight-line running and change-of-direction tasks in court-sport athletes (11 females, 11 males). During straight-line running, reduced ankle dorsiflexion (32-77% of gait cycle, mean difference [MD]: 2.6°) and toe-out angles (46-76%, MD: 2°), and increased knee abduction angles (14-20%, MD: 0.9°) were observed in high-cut footwear. During the change-of-direction task, reduced ankle dorsiflexion (28-64%, MD: 2.8°) and rearfoot inversion angles (72-87%, MD: 2.6°) were observed in high-cut footwear. Independent of collar height, female participants exhibited greater knee abduction angles during running (79-100%, MD: 5°), while they exhibited smaller knee flexion (38-49%, MD: 7.3°; and, 65-82%, MD: 9.6°), hip abduction angles (36-97%, MD: 8.6°), reduced knee extension moments (54-82%, MD: 0.8 Nm/kg), and greater hip abduction moments (33-40%, MD: 0.9 Nm/kg) during the change-of-direction task. Overall, our findings indicate that low-cut footwear allowed greater ankle mobility, while high-cut designs limited rearfoot inversion during lateral movements. Hip and knee biomechanics were similar across collar heights, but sex-based differences existed. Footwear collar selection should reflect common playing demands and individual biomechanics.