[Acquisition of the control of a novel muscular activity by electromyograph biofeedback]

Present study aimed at to examine the process that people acquire the control of a novel muscular activity, of which they have had little experience of voluntary control, by electromyograph (EMG) biofeedback. Thirty undergraduate students who were unable to move their ears served as subjects. They were asked to give tension unto the m. auricularis posterior (the muscle to draw an ear backward). A factorial design was employed with two levels of strategy (transferring, non-transferring) and three methods of how to provide with the EMG feedback signals from the m. auricularis posterior during training session (no-feedback, biofeedback, intermittent biofeedback). The experiment was consisted of four sessions: rest, pre-test, training, and post-test. Main results were as follows: (1) Two groups, which subjects used the transferring strategy and the feedback signals, significantly increased the integrated EMG of the m. auricuralis posterior from pre- to post-tests. (2) Furthermore, the EMG-increase was significantly greater in one group, which feedback signals were intermittently given at every other training trial, than another group, which feedback signals were given at all trials. (3) It was also found that no increase of awareness to the muscular tension occurred despite the increase of EMG activity.