ECSS Paris 2023: CP-BM08
INTRODUCTION: Athletic training may help athletes maintain their performance even when mentally fatigued. However, the previous studies only tested male athletes when investigating mental fatigue. Unfortunately, there is limited research comparing the effects of mental fatigue on performance between male and female athletes. The aim of the current study was to determine whether male and female varsity rugby players are similarly resistant to mental fatigue. Using a Virtual Reality (VR) crossing order task, it was hypothesized that: (1) Following a 30-minute Stroop task, performance on a VR decision-making task would decrease, with slower, more variable response times and decreased accuracy, compared to pre-fatigue levels; (2) Conditions that most closely matched the athlete’s average walking speed would be the most difficult to determine crossing order (i.e. increased response time; decreased accuracy); and (3) There would be no differences between male and female rugby players’ performance. METHODS: Eighteen (x̄ = 19.1 years ± 1.02; 9 males, 9 females) varsity rugby players participated in this study. In a virtual environment, participants approached a 90 cm doorway while a virtual person approached from the opposite side. When participants reached two meters from the doorway, the screen went blank, and they were instructed to respond as quickly and accurately as possible whether they would pass through the doorway first. The virtual person approached at four different speeds relative to the participant’s average walking speed (i.e., 0.8x, 0.9x, 1.1x, and 1.2x). After completing 20 trials they completed a 30-minute Stroop task, followed by a second block of the collision avoidance task. A 5-minute psychomotor vigilance task (PVT) was used as a behavioural measure of mental fatigue. RESULTS: Statistical analyses showed a significant increase in PVT response time following the 30-minute Stroop task, however participants’ response times did not increase nor was there evidence to suggest a decline in accuracy. Participants were substantially less accurate when the VP approached at 1.1x their walking speed, but not when the VP approached at 0.9x their average walking speed. While no sex differences in accuracy were observed, there was evidence to suggest that female rugby players demonstrated faster response times following the Stroop task compared to male rugby players. CONCLUSION: The lack of differences in performance following mental fatigue is likely due to the low cognitive demands or the simple binary decision. Regardless of the time point, accuracy was reduced when the VP’s approach speed was slightly faster than the participant’s action boundary, which may reflect increased familiarity with walking while in the virtual environment. There is some support to suggest that female athletes responded faster following mental fatigue compared to males, which may reflect different strategies under fatigue or faster processing times.
Read CV Michael CinelliECSS Paris 2023: CP-BM08
INTRODUCTION: The early pickup of task-relevant informational cues from the pitcher is a decisive factor in enhancing batting performance outcomes. An observer’s ability to accurately extract task-relevant kinematic features from a pitching pattern is constrained by affordances shaped through sport-specific expertise. Previous research has demonstrated that invariants of pitching coordination patterns are perceptually available, highlighting the visual system’s sensitivity to the structural properties of biological motion. This experiment examined perceptual performance in identifying different pitching patterns across baseball skill levels. METHODS: Thirty-six participants were recruited, including 12 Division I collegiate pitchers, 12 Division I field players, and 12 individuals without formal baseball training. Biological motion videos were obtained from two Division I pitchers (one left-handed and one right-handed) by manually digitizing 13 anatomical landmarks using Tracker software. Point-light displays representing fastball and breaking-ball deliveries, as well as strike and ball outcomes, were generated and presented in a randomized order. Participants identified pitch type, pitch location, and pitcher handedness. Recognition accuracy was evaluated using one-sample t-tests against chance level (0.5), and group differences were conducted by using Welch’s one-way ANOVA. RESULTS: The results showed that accuracy rates for all three groups were significantly higher than the random guessing probability of 0.5 (ps < .001). ANOVA indicated significant differences in accuracy rates for identifying handedness and pitching type among the three groups, where pitchers and fielders were significantly higher than individuals (ps < .001). No significant differences were found among the groups for strike/ball recognition. CONCLUSION: This study found significant differences among individuals with varying levels of expertise in identifying pitcher handedness and pitching types using dynamic point-light displays. The results demonstrate that biological motion serves as a vital tool for verifying the existence of informational invariants and examining affordances. Although mirror flipping alters the pitcher’s structural orientation and spatial coordinates, the relative motion between joints remains unchanged. These findings suggest that professional sports expertise arises from the integration of physical performance and sport-specific perceptual abilities, as kinematic information structures invariant cues that specify motion identity regardless of spatial orientation. References: Johansson G. Percept Psychophys 1973;14:201–211. Tsai KF, Liu YT. Q Chin Phys Educ 2006;20:93–101. Hsieh TY, Liu YT. Q Chin Phys Educ 2007;21:68–74.
Read CV HAO-WEI WUECSS Paris 2023: CP-BM08
INTRODUCTION: Muscular exhaustion impairs postural control, but quantifying fatigue in daily routine is often impractical. Static postural sway is a promising fatigue-sensitive outcome, traditionally measured with force plates to obtain center of pressure (CoP). With force plates rarely available for field testing, recent work suggests center of mass (CoM) may be a practical alternative measure of balance when CoP is unavailable (Richmond et al., 2021). This study aims to assess pre- to post- training changes in CoM displacement features across sessions during a static postural control task, with CoM computed from markerless motion capture. METHODS: 9 elite athletes performed 1-min quiet stance trials pre- and post-training. Post-training assessments were conducted 10–20 min post-session to avoid hyperventilation (Sakellari et al., 1997) and limiting muscle stiffness (Kawama et al., 2024). Session intensity was assessed on a 1-10 scale by athletes and coach. Primary outcomes were sway metrics derived from CoM time series, evaluated in the medio-lateral (ML), antero-posterior (AP), and radial directions using spatio-temporal features and non-linear measures: Stabilogram Diffusion Analysis (SDA) (Quijoux et al., 2021) and Sample Entropy (Ramdani et al., 2009). CoM was computed using Body-Segment Inertial Parameters (BSIP) (Dumas and Wojtusch, 2018) from segment positions reconstructed with 3D keypoints. Baseline test–retest reliability across subjects and sessions was assessed using ICC (3,k) and training-induced changes were analyzed as post–pre differences, estimated with a linear mixed-effects model and reported as estimated mean change with 95% confidence intervals. RESULTS: We recorded 18 training sessions (mean intensity = 6.94, std = 1.47). Each athlete averaged 11 sessions (std = 2.31) and 7 athletes completed at least 8 high-intensity (≥ 7) sessions. - At baseline, variance components analyses indicated that session and residual sources accounted for most variability, while the proportion attributable to stable between-subject differences remained small (ICC subject ≈ 0.02–0.26 across metrics). - At high intensity, a significant pre-to-post change was observed for the long-term SDA slope in the AP axis, with a negative mean ∆ (post < pre). Other metrics showed no clear change (95% CI crossed 0). CONCLUSION: CoM-based sway metrics extracted from markerless motion capture showed low subject-specific stability across sessions, indicating that inter-session variability exceeded inter-individual variability, with variability largely driven by session and residual effects. A significant decrease was observed for the long-term SDA slope in the AP axis, indicating reduced long-term drift and improved postural regulation. As quiet standing may be insufficiently challenging for young elite athletes, more demanding dual-task balance conditions (eyes closed, joint feet, etc.) are the next step to enhance sensitivity to individual signatures and fatigue-related changes.
Read CV Nicolas VuillodECSS Paris 2023: CP-BM08