Virtual reality has recently been recognised as an effective tool for investigating visual-perceptual tasks. To develop a sport-specific virtual environment with realistic locomotion, it is crucial to examine the effect of using virtual reality devices on athletes performing intense and complex movements. Twelve collegiate football players were instructed to perform pre-planned and unplanned sidestepping in both environments with the same dimension and experimental setup in the virtual environment as in the real one. Analysis of the performance and knee biomechanical parameters showed that movements performed in the two environments were generally comparable. Consistent changes in approach velocity and knee angle/moment under unplanned conditions (compared with preplanned conditions) were also found in the virtual environment as in the real one, except for the significantly larger peak flexion angle (p < .05) observed in the virtual environment. Interestingly, half of the participants changed from producing abduction to adduction moment at the weight acceptance phase in the preplanned condition (p < .05). These findings suggested that while it is generally feasible to use virtual reality head-mounted displays for designated experiments and training, the effect of wearing virtual reality devices could be somewhat subject-specific.

This study aimed to explore the feasibility of using OpenCap with a lab-based multi-camera motion capture (MOCAP) system and to evaluate the influence of camera configurations on the trunk and lower-limb kinematic accuracy for athletic movements. Six top-level female football players performed drop jump (DJ) and sidecut (SC) tasks while their motion was recorded synchronously by marker- and video-based cameras. Lower-limb and trunk joint angles, as well as pelvis translations and rotations, obtained with three camera configurations—two, four, and eight cameras—were compared with the marker-based reference. Statistical parametric mapping repeated measures ANOVAs revealed significant differences in kinematic waveforms, decreasing from 16 and 14 degrees of freedom in the two-camera configuration during DJ and SC, respectively, to 9 degrees of freedom in the eight-camera configuration. Improvements in root mean square error were also observed in pelvis anterior–posterior translation and pelvis rotation in both tasks; vertical translations, right ankle dorsiflexion, and inversion in DJ; lumbar bending, and right hip rotation in SC. The result suggested that using a lab-based MOCAP system with more cameras could modestly enhance accuracy and provide several advantages, e.g., broader camera coverage. However, further investigation is needed to ensure the differences are biomechanically meaningful.

Although the support foot plays an important role in kicking a football, there has been a paucity of research exploring the effect of the placement of the support foot on kicking performance. To investigate the kick performance under different support foot positions, ten male footballers were recruited to participate in two experiments: one determining the maximum ball speed and the second determining accuracy. The participants were instructed to plant their support foot on one of nine different spots marked in the form of a 3 × 3 shape on a piece of artificial grass and asked to kick the ball. In the first (maximum speed) test, the participants tried their best to kick the ball at the maximum ball speed from nine different support foot positions. In the second (accuracy) test, the participants kicked the ball toward the target area without restricting the support foot position. The ball speed, as well as the success rate, were recorded from each support foot position. Significantly higher ball speed and accuracy were obtained at medial positions than was the case at lateral positions from the nine spots. It was concluded that although footballers may choose different positions for support foot placement, the maximum ball speed and better accuracy could be expected when the support foot was next to or slightly in front of the ball centre without too much side-by-side separation (27–37 cm).

Traditional sidestepping experiment often relies on simplified visual stimuli that lack ecological validity. This study aimed to develop a fully immersive, football-specific virtual reality (VR) system to examine knee biomechanics during sidestepping in response to realistic visual stimuli. Twelve male collegiate footballers performed unanticipated sidestepping in response to a virtual footballer avatar executing either non-deceptive (VF-ND) or deceptive (VF-D) dribbling. Despite similar approach velocity and stance time, participants exhibited greater knee flexion angles and abduction and internal rotation moments in VF-D trials. Secondary analyses compared the results with previously reported arrow-preplanned (A-PP) and arrow-unplanned (A-UP) trials from the same participants. Approaching velocity decreased, and stance time increased in the following order: A-PP, VF-ND, VF-D and A-UP. Knee flexion angles and abduction moments increased, while peak internal rotation moments decreased in the same order. These findings suggested that the VR-based approach imposed more realistic visuospatial and temporal constraints than traditional methods, enhancing ecological validity. As in real environment, players in VR can perceive subtle cues, distinguish deceptive from non-deceptive actions and adapt their movements accordingly. Practitioners should design their protocols to resemble real-world scenarios as closely as possible and interpret the biomechanical outcomes cautiously when comparing across different visual stimuli.

This study compared the kinematic and neuromuscular characteristics of the tennis forehand drive between high-performance (HP) and intermediate (INT) players. Eighteen right-handed male players (HP: n = 9; INT: n = 9) performed cross-court forehands while three-dimensional motion capture and surface electromyography (EMG) were recorded from the dominant upper limb and trunk. Kinematic and EMG data were time-normalized to the forward swing. One-dimensional statistical parametric mapping two-sample t-tests were used to compare joint angles, angular and linear velocities, and EMG amplitude waveforms between groups. Bonferroni-corrected significance levels were set at α = 0.0017 for kinematic variables and α = 0.0063 for EMG data. HP players exhibited greater racket linear velocity during the final part of the forward swing, accompanied by higher shoulder, elbow and wrist linear velocities, whereas hip linear velocity did not differ between groups. Joint angles were broadly similar, with SPM revealing only slightly greater early knee flexion in HP players. In contrast, HP players showed higher hip and knee angular velocities and greater wrist angular velocities in both flexion/extension and radial/ulnar deviation towards impact. EMG patterns were generally comparable, but HP players displayed higher biceps brachii activation in two significant clusters during the mid-to-late forward swing and greater triceps brachii activation in the late forward swing. No significant differences were observed for deltoid, pectoralis major, latissimus dorsi, flexor carpi radialis or extensor carpi radialis. These findings indicate that superior forehand performance in HP players is associated primarily with refined segmental coordination, greater lower-limb and distal segment velocities, and locally increased elbow muscle activation, rather than with widespread increases in upper-limb or trunk muscle activity.