EMG And Torque Differences During Supported And Unsupported Isokinetic Bicep Curl Exercise

Abstract

PURPOSE: To compare the electromyographic (EMG) activity of three elbow flexors (biceps brachii, brachioradialis, pronator teres), and isokinetic torque responses during standing bicep curl (SC) and preacher curl (PC) exercise. METHODS: Ten male subjects (aged 21.8 ± 2.4 years), performed fifteen maximal isokinetic contractions using supported and unsupported elbow positions, at three selected randomized velocities (60 deg·sec−1, 150 deg·sec−1, and 240 deg·sec−1). EMG recordings were made at the biceps brachii (BB), brachioradialis (BR), and pronator teres (PT) sites. RESULTS:Repeated Measures ANOVA revealed no significant differences in EMG Root Mean Square across muscles during the isometric SC (BB: 0.312±.20; BR:0.179±0.04) and PC (BB:0.229±0.11; BR: 0.196±0.06). There were significant differences (p<0.05) in PT amplitudes (SC 0.174±0.05; PC 0.13±0.03). RM ANOVA indicated non-significant differences in EMG across the testing speeds. There were significant differences in isometric torque (SC: 88.51±9.17Nm vs PC: 79.69±7.22Nm, p<0.05). A two-way ANOVA procedure revealed significant torque differences at 150 deg·sec−1 (SC:48.54±8.45 Nm, PC: 37.29±5.28Nm) and 240 deg·sec−1 (SC:41.81±10.84; PC: 31.80±8.88 Nm). CONCLUSIONS: There were no significant differences in EMG activity during any of the isokinetic testing velocities. Significantly greater torque production was elicited during the standing curl at the two faster isokinetic velocities.