Quantification of Goal-Directed Stepping Behavior Under Two Limb Choice Conditions in Neurotypical Adults: A Preliminary Investigation

During reaching, arm choice depends on handedness, success, and effort; however, whether these factors influence leg choice for goal-directed stepping is still unknown. We aimed to quantify the kinematics and behavioral patterns of leg choice and to explore whether success and/or effort influence leg choice during goal-directed stepping under two Choice conditions in 20 right-leg dominant neurotypical adults. We adapted the classic center-out target array; participants stepped to pre-cued targets with an emphasis on accuracy without time constraints. The first set of trials was always Free for which either leg could be chosen. The second set of trials was verbally Constrained for which there was no choice as only the left non-dominant leg was to be used. We separately compared success, effort, and subjective difficulty between Free and Constrained trials for left and right target regions. In Free, participants uniformly selected the limb ipsilateral to the target. While success and subjective difficulty were not influenced by Choice, effort varied depending on Choice. Our preliminary findings suggest that during goal-directed stepping, leg choice depends on effort and may be independent of leg dominance and subjective difficulty, while the difficulty of the Constrained Choice condition can improve success independent of leg used.