Inter-individual variability in the patterns of responses for electromyography and mechanomyography during cycle ergometry using an RPE-clamp model.

Abstract

To examine inter-individual variability versus composite models for the patterns of responses for electromyography (EMG) and mechanomyography (MMG) versus time relationships during moderate and heavy cycle ergometry using a rating of perceived exertion (RPE) clamp model. EMG amplitude (amplitude root-mean-square, RMS), EMG mean power frequency (MPF), MMG-RMS, and MMG-MPF were collected during two, 60-min rides at a moderate (RPE at the gas exchange threshold; RPEGET) and heavy (RPE at 15% above the GET; RPEGET+15%) intensity when RPE was held constant (clamped). Composite (mean) and individual responses for EMG and MMG parameters were compared during each 60-min ride. There was great inter-individual variability for each EMG and MMG parameters at RPEGET and RPEGET+15%. Composite models showed decreases in EMG-RMS (r (2)=-0.92 and R (2)=0.96), increases in EMG-MPF (R (2)=0.90), increases in MMG-RMS (r (2)=0.81 and 0.55), and either no change or a decrease (r (2)=0.34) in MMG-MPF at RPEGET and RPEGET+15%, respectively. The results of the present study indicated that there were differences between composite and individual patterns of responses for EMG and MMG parameters during moderate and heavy cycle ergometry at a constant RPE. Thus, composite models did not represent the unique muscle activation strategies exhibited by individual responses when cycling in the moderate and heavy intensity domains when using an RPE-clamp model.