Does the stability of elbow support influence the elbow joint matching accuracy?

The aim of the present work was to determine if the elbow joint instability and translatory movements during elbow flexion lead to significant errors in elbow angle perception. The matching elbow was fixed on a rocking platform of two different heights so that the elbow flexion was associated with tilting movement of the support and the angle/torque relationship changed depending on the height of the platform. The matching on any of the rocking supports did not cause an over-flexion constant error but it did increase the error variance, especially in the high rocking support condition. An adaptation to the rocking support condition was revealed by an after-effect resulting in an overestimation of the reference angle in the final testing on a rigid support. It is concluded that the elbow angle perception is modified as a result of adaptation to the rocking support, which is associated with recalibration of position sense during the experimental session. The results are consistent with the hypothesis that the estimation of the elbow joint angle depends on the internal representation of the arm's dynamics.