Electromyography during Wingate upper body exercise

Introduction The specific muscles contributing to power production and/or stabilisation during arm crank ergometry (ACE) have been examined (Smith et al., 2008: Journal of Electromyography & Kinesiology, 18, 598–605). To the authors knowledge these muscles have not been examined during Wingate anaerobic testing (WAnT) for ACE. Therefore, the purpose of the research was to examine EMG during WAnT for ACE. Methods Following institutional ethical approval thirteen male students (Age 21.9, s = 7.0 years) volunteered to participated in this study. Each participant completed five seated upper body WAnTs using a table mounted cycle ergometer (Monark 894E, Monark Exercise AB, Sweden) using 2, 3, 4 and 5% body mass (BM) as resistive loads. The order of testing was randomised with a minimum of 24-h between tests. The first test, 4% BM, was a familiarisation session. Before each test a standardised warm-up including three 3-4 s practise sprints against 4% BM was completed. Corrected and uncorrected peak power (PP; over 1 s duration) and mean power (MP; over 29 s duration) were recorded using Cranlea UK Wingate software (version 4.0). During the warm-up sprints the peak EMG (3-4 s) was used to normalise the WAnT EMG data. Data were recorded using double-differential (16-3000Hz bandwidth, x300 gain), bipolar, active electrodes (MP-2A, Linton, Norfolk, UK). The average root-mean-square (RMS) value for each muscle was calculated over 250-ms, for each trial. The following sites were examined: flexor carpi ulnaris (FCU), biceps brachii (BB), triceps brachii lateral (TB), anterior deltoid (AD), infraspinatus (I), external oblique (EO), vastus medialis (VM) and lateral soleus (LS). Statistical analysis: EMG data at peak power and fatigue were analysed by general linear model (SPSS 17.0) with Bonferroni correction. Significance was accepted with P < 0.05. Effect size range .010 to .312 (eta squared). Results At the end of the test (29 s) there were significant differences in normalised EMG responses for, AD at 5% versus 2, 3 and 4%, BB at 5% versus 2 and 3%, TB at 5% versus 2% and 2% versus 3% and OE 2% versus 4 and 5%. Peak power BB was significantly different at 2% versus 5% and approached significance (P=0.068) for EO. There were no significant differences between trials for the remaining muscles although at 29 s FCU at 5% versus 2% and TB 2 versus 4% approached significance (P = 0.057 and P = 0.081 respectively). Discussion During WAnT ACE at 29 s the AD appears to contribute an increasing role to arm stabilisation and/or power produced. Greater EMG activity at 2 vs 5% BM loads represents greater muscular effort. Conclusion The results suggest lower loads (2% BM), may be better for shoulder injury rehabilitation, whereas, a 4 or 5% BM load is suggested for power training. BB and EO may contribute a significant proportion to power production towards the end of the WAnT.