ECSS Paris 2023: CP-BM15
INTRODUCTION: An essential component of individual and team success in basketball is decision-making ability. Critically, basketball coaches require reliable and valid tools to assess this skill to aid their talent evaluation processes. To address previous challenges in examining decision-making, the current study aimed to create a laboratory-based perceptual task that could serve as a proxy for in-game decision-making ability. METHODS: Grounded in ecological psychology, the perceptual task allowed participants to perceive and act upon collision and aperture affordances in a virtual reality environment. The study sample included Canadian university basketball players and non sport-playing Canadian university students (x̄ = 21.14 years ± 2.43; 17 athletes and 19 non athletes). RESULTS: Two separate two-way mixed ANOVAs revealed that basketball players were more accurate (F(1, 34) = 4.327, p = 0.045, ω² = 0.052) and more consistent (F(1, 34) = 7.695, p = 0.009, ω² = 0.156) than non-athletes on the perceptual task. Correlational analyses suggested that consistent performance on perceptual task was moderately associated with higher assists (r(14) = 0.41 [-0.11, 0.75], p = 0.119), higher turnovers (r(15) = 0.42 [0.05, 0.79], p = 0.093), and higher box creation scores ((r(15) = 0.47 [0.10, 0.78], p = 0.060) CONCLUSION: Overall, the current study lays the foundation for a more holistic testing of athletes and challenges traditional approaches to evaluating decision-making. Future iterations of the perceptual task could prove useful for talent identification and investigations of decision-making ability in basketball players.
Read CV Jackson KellyECSS Paris 2023: CP-BM15
INTRODUCTION: In target-aiming motor tasks, increasing target distance instinctively evokes the need for greater force exertion. For example, in golf, demands for greater distance often trigger “over-swinging”—an excessive force exertion that paradoxically degrades performance. We propose that this phenomenon arises from a “speed-dominant adjustment” strategy. Although actual ball distance is determined by both launch angle and velocity, humans tend to perceive speed control as a more intuitive and reliable variable than angle control. Consequently, performers increase movement speed even when the required distance could be achieved solely through angle adjustments. We hypothesized that this distance-induced over-powering compromises movement smoothness and tested this hypothesis using a target-aiming throwing task. METHODS: Thirteen participants performed a ball throwing task toward targets at two distances (3.0 m and 4.5 m) under two instruction conditions: accuracy-over-velocity (AV) and velocity-over-accuracy (VA). Ball release velocity, release angle, and release height were measured. Movement smoothness was quantified using jerk cost (JC), calculated from the angular kinematics of the wrist, elbow, and shoulder joints. Using a flight-trajectory simulation that incorporated air resistance, the theoretical minimum angle required to reach 4.5 m was computed based on the measured release velocity in the 3.0 m condition. RESULTS: A two-way ANOVA revealed that both release velocity and release angle increased significantly with target distance and instruction condition, with no interaction effects. Notably, in the VA condition, the measured release angle at 4.5 m was statistically equivalent to the theoretical angle required to reach the target using the 3.0 m release velocity. This indicates that participants had already secured a kinematic configuration sufficient to extend the reachable distance to 4.5 m without additional acceleration. Nevertheless, participants significantly increased their velocity. This superfluous increase in speed was accompanied by significant increases in JC at the elbow and shoulder joints, indicating reduced movement smoothness. CONCLUSION: The absence of interaction effects suggests that distance-dependent increases in movement speed are a robust feature of motor scaling. Critically, the VA-condition results provide direct evidence of over-powering: participants applied additional power despite already possessing a kinematic configuration that was physically sufficient to achieve the required throwing distance. The concomitant increase in JC suggests that prioritizing speed over strategic angle adjustment disrupts motor coordination efficiency. These findings demonstrate that “trying too hard” to overcome distance through speed leads to kinematic degradation, offering a mechanistic explanation for suboptimal performance in far-aiming motor tasks.
Read CV Tsubasa WakatsukiECSS Paris 2023: CP-BM15
INTRODUCTION: Muscle architecture is closely related to muscle function [1]. That is, muscle fibre arrangement can change to force or velocity dominant positions. While these chronic training adaptations are well known, the acute effect of fatigue on pennation angle remains inconclusive. The aim of this study was to evaluate pennation angle changes following a dorsiflexion specific fatigue intervention METHODS: Twenty-six healthy recreational athletes (Body stature: 168.9 ± 9.5cm; mass: 66.3 ± 9.8kg) volunteered for the study. were recorded. An isometric fatiguing intervention was applied where participants were required to produce maximal dorsiflex force a duration of 20 seconds across three repetitions. This was repeated over 4 sets and isometric dorsiflexion forces were measured using a VALD DynaMo. Isokinetic dorsiflexion peak power and Countermovement jump (CMJ) heights were evaluated prior to and following the fatiguing protocol. Finally, ultrasonography evaluated the tibialis anterior, lateral and medial gastrocnemius pennation angles, before and after the first isometric and isokinetic attempts. Ultrasonography was also measured after the second to fourth isometric attempts, second isokinetic attempt and CMJ heights. Paired data were analysed using Wilcoxon signed ranked and Friedman’s tests in SPSS 30, with p<0.05. RESULTS: Isometric dorsiflexion force differences (p>0.001) were noted between attempts 1 (292.54 ± 65.23 N) and 2 (278.00 ± 64.27N), 1 and 3 (270.65 ± 93.14 N), and 1 and 4 (263.85 ± 79.74N). Additionally, Isokinetic peak power declined (34.68 ± 13.09 vs 16.40 ± 5.74 W; p<0.001). However, no difference in CMJ height (30.58 ± 7.98 vs 31.17 ± 8.54 cm; p=0.382). Specific to muscle architecture, pennation angle of the tibialis anterior (p= 0.786; lateral gastrocnemius p=0.833; medial gastrocnemius p=0.271) all remained statistically unchanged. CONCLUSION: While the isometric fatigue protocol of the dorsiflexors was effective, it seems the pennation angles of the tibialis anterior and gastrocnemius remain unaffected. It is likely that muscle fibres maintain their orientation following a bout of acute isometric fatigue. The effects of eccentric and concentric actions may alter the pennation angles due to the greater range of motion required during the joint movement. Indeed, pennation angle is known to change following movements like squats [2], [3]. References 1. Sekir et al. (2019). Effects of Static and Dynamic Stretching on Muscle Architecture. Turk J Sports Med, 54(3):158. 2. Vieira et al. (2018). Acute changes in muscle thickness and pennation angle in response to work-matched concentric and eccentric isokinetic exercise. Appl Physio, Nut Metabol, 43(10): 1069. 3. Coenning et al. (2024). Impact of contraction intensity and ankle joint angle on calf muscle fascicle length and pennation angle during isometric and dynamic contractions. Sci Reports, 14:24929.
Read CV Andrew GreenECSS Paris 2023: CP-BM15