MUSCLE ACTIVATION PATTERNS DURING TOTAL-BODY STEADY-STATE EXECISE

Abstract

870 Physiological responses to exercise vary with mode and intensity. The standard treadmill and cycle ergometers have allowed researchers to study these responses during walking, running, and cycling. However, newly designed ergometers that combine both upper and lower extremity exercise creates yet another mode of exercise. This new mode of exercise potentially increases the muscle mass used to perform the activity and, therefore, may alter the physiological responses. The purpose of this study was to examine the concentric activation patterns of brachioradialis (BR), triceps (TR), posterior (PD) and anterior deltoid, pectoralis major, latissimus dorsi, vastus lateralis, and rectus femoris muscles located on the right side of the body during steady-state exercise on a total-body recumbent stepper (RS) using surface electromyographic technique. Twelve healthy college students (8M, 4F) exercised at 46% VO2 peak until an equivalent of 300 kcal was expended. Oxygen consumption, heart rate, ratings of perceived exertion, and integrated EMG were monitored continuously, and an average IEMG values were analyzed at the fifth and final minute of exercise. An ANOVA with repeated measures (p<0.05) revealed a significant decrease in force exerted by upper body muscular activity, with significant decreases observed in the BR, TR, and PD muscles. These findings suggest that when exercising on the total-body RS, the degree of muscle activation shifts among various muscles in order to maintain steady-state.