An Electromyographic Analysis of the Shoulder While Performing Exercises Using the Bodyblade Classic and Pro

Abstract

PURPOSE: The Bodyblade, which is an exercise device which oscillates back and forth with the shoulder in varying positions with little movement, is used during shoulder rehabilitation. The purpose was to compare glenohumeral and scapular muscle activity using electromyography (EMG) while performing exercises with the Bodyblade Classic (BBC) and Pro (BBP). METHODS: Eighteen healthy subjects participated, nine males and nine females, with a mean age of 28.1(6.8) yo. Seven exercises were performing both with the BBC and BBP: 1) One hand up and down motion with arm at side; 2) One hand front to back motion with shoulder flexed 90°; 3) One hand up and down motion with shoulder abducted 90°; 4) One hand side to side motion with arm at side and elbow flexed 90°; 5) Two hand side to side motion with shoulders flexed 90°; 6) Two hand up and down motion with shoulders flexed 90°; and 7) Two hand front to back motion with shoulders flexed 90°. Surface electrodes were positioned on the right anterior and posterior deltoids, sternal pectoralis major, latissimus dorsi, infraspinatus, upper and lower trapezius, and serratus anterior. Electromyographic (EMG) data were collected from a Noraxon EMG system during 12 sec of continuous motion for each exercise. EMG exercise data were normalized by maximum voluntary isometric contractions (MVIC). A two-factor repeated measures ANOVA (p < 0.01) assessed EMG differences. RESULTS: Compared to other exercises, EMG was significantly greater in BBC3 and BBP3 (anterior and posterior deltoids), BBC4, BBC5, BBP4, and BBP5 (sternal pectoralis major), BBC1, BBC3, BBP1, and BBP3 (latissimus dorsi), and BBC3, BBC6, BBP3, and BBP6 (upper trapezius), and significantly lower in BBC1, BBC7, and BBP1 (lower trapezius), BBC1, BBC4, and BBP1, BBP4 (serratus anterior), and BBC1,BBC5, BBC7, BBP1, and BBP5 (infraspinatus). There were generally no EMG differences in exercises between BBC and BBP. Females generally exhibited greater EMG than males. CONCLUSIONS: Because moderate (20-40% MVIC) muscle activity was generated for most exercises with little shoulder motion, the Bodyblade appears to be an effective device to employ to enhance shoulder muscle endurance (males more than females) and strength (females more than males) during rehabilitation and training, especially when limited joint motion is desired.