The effects of grip force on wrist kinematics in response to sudden perturbations

This work evaluated the effects of grip force magnitude and forearm muscle activity on wrist kinematics in response to sudden wrist perturbations. A haptic wrist robot delivered perturbations that caused wrist flexion, extension, radial and ulnar deviation. Prior to each perturbation, participants performed a submaximal grip task at 4 magnitudes (5%, 20%, 50% and 80% of maximum). This work showed a decrease in angular wrist displacement with increased grip forces. This was consistent, regardless of perturbation direction and enhances our understanding of the relationship between grip demands and wrist stiffness.