EMG Feedback as a Muscle Reeducation Technique: A Controlled Study

Abstract

In an effort to evaluate the efficacy and function of EMG feedback in muscle reeducation, improvement of the abductor function of the abductor hallucis muscle was studied under three training conditions involving 1) EMG feedback, 2) sensory stimulation or 3) equal time for unassisted practice; and a fourth, control condition involving testing without training. Active range of motion was measured before and after training to assess ability to use the muscle as an abductor. EMG activity was quantified for a 1-minute test contraction to evaluate ability to maintain and maximize a voluntary contraction of the target muscle. The results indicated that EMG feedback was highly effective when subjects had little initial use of the target muscle. EMG feedback improved the ability of these subjects to maintain and maximize voluntary muscle contractions, as demonstrated on the EMG measure. EMG feedback did not add to the learning situation when only a relatively brief, phasic contraction was required, as on the range-of-motion measure; similar gains were made with equivalent practive without EMG feedback. When subjects already had considerable use of the target muscle prior to training, EMG feedback may have actually interfered with training; in this case unassisted practice was more effective.

The Effect of Differing Feedback Conditions on Grip Strength: A Pilot Study

“…In a study by Middaugh (1978) on the effectiveness of EMG feedback for improvement of function of the abductor hallucis muscle, extrinsic feedback was found to be effective only for those subjects who did not have the ability to use this muscle as an abductor. Possibly the assessment of a task or a skill that is already learned, such as grip strength, does not benefit from extrinsic feedback.…”

“…Biofeedback has developed treatments that have been used with clinical success in the treatment of a number of disorders: recovery of movement loss due to stroke (Basmajian, 1967;Middaugh, 1978), relaxation of hyperactive neck muscles (Korein, Brudny, Grynbaum, Sachs-Frankel, Weisinger, & Levidow, 1976), head and limb control in cerebral-palsied children (Block & Silverstein, 1978;Wooldridge & Russel, 1976), and several other neurological conditions such as paraplegia (Dunn & Eads, 1979), parkinsonism (Hand, Burns, & Ireland, 1979), and Bell's palsy (Brown, Nahai, Wolf, & Basmajian, 1978).…”

Researchers and Clinicians: A Growing Divide or Narrowing Gap?

“…Researchers today are asking clinically relevant questions and answering many of these questions. Our journals have moved from publishing study after study on biological plausibility of our interventions and trivial explorations of EMG activity in abductor hallucis, 34 to patient-oriented and clinically relevant investigations, commentaries, and editorials in virtually every issue. My opinion is that the chasm has now narrowed to the point where the researchers are standing shoulder-to-shoulder with clinicians to investigate clinical practice.…”

Influence of Mental Practice on Development of Voluntary Control of a Novel Motor Acquisition Task

“…Research has demonstrated that it is possible to train subjects to recruit voluntarily the abductor hallucis for big toe abduction while avoiding excessive simultaneous activation of the other intrinsic foot muscles (Middaugh, 1978;LeDoux & Quinones, 1981;Middaugh, et al, 1982;Tohya, 1991), but mental practice has not been included as an intervention. LeDoux and Quinones (1981) employed electrical stimulation to train their subjects over a 3wk, period, whereas Tohya (1991) employed various cognitive strategies with his subjects.…”

“…The time required for acquisition in these studies was not specified, although Tohya reported that a relatively long duration was needed. Middaugh (1978) compared normal sensory input (tactile and proprioceptive) to ele~trom~ographic (EMG) biofeedback and showed increased EMG output of the abductor hallucis and increased active range of motion in big toe abduction in her subjects after only 20 min. training.…”