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Full-Text Articles in Social and Behavioral Sciences
Postural Responses To Multidirectional Perturbations To The Hand During Stance, Ali Forghani, Sheida Rabipour, Theodore E. Milner, Paul J. Stapley
Postural Responses To Multidirectional Perturbations To The Hand During Stance, Ali Forghani, Sheida Rabipour, Theodore E. Milner, Paul J. Stapley
Dr Paul J Stapley
Humans are easily able to maintain their balance while applying force with their hands to move or stabilize objects. Based on Newton's laws, the applied force must be counteracted by ground reaction force (GRF) to maintain balance. However, because the GRF is partitioned between the two legs there is no unique solution. Furthermore, central nervous system (CNS) can employ an infinite number of muscle activation patterns to achieve ground reaction force (GRF) vectors needed to satisfy both the task-level goal and balance. This study examines the postural response when hand position must remain stable as an external force is applied …
Equilibrium Constraints But Not Joint Constraints Determine Hand Trajectory Planning, C Paizis, C Papaxanthis, P Stapley, T Pozzo
Equilibrium Constraints But Not Joint Constraints Determine Hand Trajectory Planning, C Paizis, C Papaxanthis, P Stapley, T Pozzo
Dr Paul J Stapley
Introduction: Equilibrium constraints play a major role in finger trajectory formation and curved hand paths seem to be the result of a strong coupling between postural and focal task components. However, such curvatures might also result from joint constraints. To test this hyputhesis we investigated the elrect of imposed joint strategies and support conditions on hand trajectory formation during a pointing task beyond arm's length.