EFFECT OF REAL-TIME EMG BIOFEEDBACK ON SELECTIVE ACTIVATION OF THE INFRASPINATUS AND POSTERIOR DELTOID DURING THERABAND SHOULDER EXTERNAL ROTATION EXERCISE IN INDIVIDUALS WITH ROUND SHOULDER POSTURE

The infraspinatus supports glenohumeral stability and external rotation, but compensatory posterior deltoid activity disrupts muscle balance and contributes to dysfunction, particularly in individuals with round shoulder posture (RSP). Real-time surface electromyographic (EMG) biofeedback provides visual cues that may promote selective activation of the target muscle while minimizing unwanted activity. This study aimed to determine the effects of real-time EMG biofeedback on selective activation of the infraspinatus and inhibition of the posterior deltoid during seated shoulder external rotation. Thirty adults with RSP performed two exercise conditions, with and without real-time EMG feedback. Surface EMG electrodes were placed over the infraspinatus and posterior deltoid. Isometric contractions were held for 5[Formula: see text]s, with EMG data from the middle 3[Formula: see text]s analyzed using root mean square and %MVIC normalization. Paired t-tests were used to compare muscle activation and activation ratios. Infraspinatus activation significantly increased in the biofeedback condition ([Formula: see text]), whereas posterior deltoid activity significantly decreased ([Formula: see text]). The infraspinatus-to-posterior deltoid activation ratio also significantly rose with biofeedback ([Formula: see text]). Real-time EMG visual feedback during seated TheraBand shoulder external rotation enhanced infraspinatus activation and reduced posterior deltoid coactivation, potentially improving motor control and rehabilitation in individuals with RSP.