ELECTROMYOGRAPHIC ACTIVITY AND APPLIED LOAD DURING SHOULDER REHABILITATION EXERCISES USING ELASTIC RESISTANCE

Muscle activity (measured by electromyography) and applied load were m easured during seven shoulder rehabilitation exercises done with an el astic resistance device. Nineteen men with no shoulder abnormalities p erformed seven exercises: external and internal rotation, forward punc h, shoulder shrug, and seated rowing with a narrow, middle, and wide g rip. Qualitative video (60 Hz) was synchronized with the electromyogra phy data from eight muscles (2000 Hz). Fine-wire intramuscular electro des were inserted into the supraspinatus and subscapularis muscles, an d surface electrodes were placed over the anterior deltoid, infraspina tus, pectoralis major, latissimus dorsi, serratus anterior, and trapez ius muscles. Ten trials per subject were analyzed for average and peak amplitude, and the results were expressed as a percentage of maximum voluntary contractions. The peak loads for all exercises ranged from 2 1 to 54 N. The muscle activity patterns suggest that these shoulder re habilitation exercises incorporating elastic resistance, controlled mo vements, and low initial loading effectively target the rotator cuff a nd supporting musculature and are appropriate for postinjury and posto perative patients.