Fig. 8.
A: illustration of a task performed by 2 muscle groups, flexors (agonists) and extensors (antagonists). The thresholds of the 2 muscle characteristics are shown as λFL (flexor) and λEXT (extensor). The initial state is shown by the vertical dotted line connecting 2 black dots on the flexor and extensor characteristics. Vibration of extensors is expected to result in perception of larger values of both muscle length and force produced by those muscles (point V, corresponding to lower net torque and end-effector force). B: perception of higher force caused by vibration of antagonist muscles may be expected if the referent coordinate (RC) of the effector shifts to RCV. The slanted lines show the effector characteristics.