The effects of EMG Biofeedback in physical therapy have been documented in many studies. EMG biofeedback has been shown to produce more rapid and significantly greater development of strength when combined with more traditional forms of physical therapy. EMG biofeedback has been successfully used for muscle reeducation and muscle strengthening in hemiplegic patients, rehabilitation following surgery or trauma, selective training of the vastus medialis during patella realignment. More recently, the use of EMG biofeedback training to remediate lower back pain has been studied.
The studies on the effects of EMG Biofeedback on strength acquisition have been sparse. Following participation in weight training, less EMG activity is observed at submaximal force relative to prior participation (Fleck & Kraemer 1987). Croce (1986) studied the effects of EMG biofeedback on isokinetic strength development in untrained college students. Croce used an Isokinetic leg extension apparatus to monitor torque produced by the quadriceps.
Closed chained, or multi-joint exercises have been recognized to offer many advantages over open chain, or single joint exercises for both physical therapy and strength development. Future research may study the effects of EMG biofeedback on isotonic close chain, or multi-joint exercises such as in leg press movement. Multiple muscles could then be monitored simultaneously and studied. The synergistic effects of agonist and secondary synergistic muscles may be studied as subjects strategically attend to multiple signals.
The question for effectiveness of EMG biofeedback for the power athlete still remains unclear. The mere achievement of isotonic resistive training may serve as its own biofeedback render EMG biofeedback useless. If EMG biofeedback shows to be effective, a decrease of EMG activity may be prove to be advantageous with isotonic weight training, particularly for monitoring coactivation of antagonist muscles involvement. These questions will have to be addressed in future research.