Changes of postural gain scaling by constrained somatosensory cues

Abstract

Somatosensory signals are known to have an important role in human postural responses which could be described in terms of feedback control gains. In the present study, the changes of feedback control gains were investigated to see the effects of somatosensory cues to the postural control strategy. To observe how postural control strategy changes with altered somatosensory cues, we applied backward perturbation to 6 young volunteers both in firm supporting surface and compliant supporting surface. As the result, ankle gains decreased when subjects stood on a compliant surface and the hip gains remained unchanged. From kinematic data, we also found that changed of hip angle with respect to ankle angle were increased as well as changes of hip torque with respect to ankle torque. These results demonstrate that, the altered somatosensory cues made the ankle gain decreased and consequently made contribution of ankle strategy decreased relative to hip strategy.