For a reach-to-grasp reaction to prevent a fall, it must be executed very rapidly, but with sufficient accuracy to achieve a functional grip. Recent findings suggest that the CNS may avoid potential time delays associated with saccade-guided arm movements by instead relying on peripheral vision (PV). However, studies of volitional arm movements have shown… (More)
A fundamental principle that has emerged from studies of natural gaze behavior is that goal-directed arm movements are typically guided by a saccade to the target. In this study, we evaluated a hypothesis that this principle does not apply to rapid reach-to-grasp movements evoked by sudden unexpected balance perturbations. These perturbations involved… (More)
Reaching to grasp an object for support is a common and functionally important response to sudden balance perturbation. The need to react very rapidly (to prevent falling) imposes temporal constraints on acquisition and processing of the visuospatial information (VSI) needed to guide the reaching movement. Previous results suggested that the CNS may deal… (More)
Balance-recovery reactions that involve rapid step or reach-to-grasp movements are prevalent and functionally important responses to instability. Successful use of these reactions to recover balance in daily life requires a capacity to modulate the reaction to deal with the continual variation in environmental constraints that occurs as the person moves,… (More)
Grab-bars and transfer poles are common sit-to-stand aids for mobility limited older adults. This study investigated differences in kinetics and kinematics to characterize the lower-limb strength and dynamic balance requirements across different pole configurations and positions in nine mobility limited older adults. Poles were varied by location (near and… (More)
Many eye-tracker systems display the point of central gaze fixation on video images of the viewed environment. We describe here a method for determining the visual angles of objects located in the periphery. Such data are needed to study the potential contributions of peripheral vision during cognitive and motor tasks.