Author(s): BODDY, A., CONTEMORI, S., WALLIS, G., MANN, D., CARROLL, T., Institution: THE UNIVERSITY OF QUEENSLAND, Country: AUSTRALIA, Abstract-ID: 2528

INTRODUCTION:
Successful skill execution in high-velocity interceptive sports requires transforming visual information into action within severe temporal constraints. Skilled actions are typically attributed to conscious visual processing and motor planning through cortical pathways. However, laboratory-based reaching studies reveal a phylogenetically preserved fast-response system operating via subcortical structures that generates inflexibly time-locked express visuomotor responses (eVMR)—eye movements and premotor muscle bursts from ~70ms after target onset (1-4). Kinematic movement appears driven not by these early responses but by a subsequent burst of cortically generated muscle activity, leaving the functional role of the subcortical pathway unclear. We therefore asked whether eVMR contribute meaningfully to performance in ecologically valid, time-critical, real-world tasks. To test this, we developed a ball-catching paradigm inspired by slip-catching in cricket.
METHODS:
Twenty skilled cricketers performed a catching task with tennis balls propelled from two laterally positioned ball machines set behind an occluding screen (Ball velocity ~46km/h, reaction time window 300-320ms). We recorded eye movements (EOG), upper-limb kinematics (accelerometer), and muscle activity (surface EMG) of the pectoralis major and posterior deltoid. Ball presentation time was determined by infrared sensors and a microphone.
RESULTS:
Robust express responses (~65-95ms) were observed on most trials with limb kinematic movement initiated within 100ms of target presentation in a substantial subset of trials (error rates <3% dismissing anticipatory strategies). This markedly exceeds computer-based reach tasks findings where eVMR are detected in the pectoralis major and posterior deltoid on only 59% and 54% of trials respectively (4), and reaction time <130ms classified as anticipatory (3) or as outliers (1,2). Together, this indicates that the subcortical pathway is functioning to facilitate movement in high-velocity catching.
CONCLUSION:
This study provides new evidence that limb movements are meaningfully initiated by the first subcortical wave of muscle activity that occurs prior to cortical visuomotor processing in a real-world sporting task. Understanding the mechanism underlying rapid reaction capabilities and how to engage it has potential applications for: (1) talent identification using neurophysiological markers; (2) informed targeted junior development; (3) monitoring athlete readiness and fatigue through response latency tracking; and (4) developing perceptual-motor training interventions that engage subcortical pathways. Furthermore, this paradigm translates to other sports/skills (e.g. racquet sports, goalkeeping, and combat) where rapid target detection and response are performance-critical.

References:
1. Pruszynski et al. (2010).
2. Gu et al. (2016).
3. Contemori et al. (2021).
4. Contemori et al. (2022).