Meeting Abstract

P1.157  Monday, Jan. 4  Patterns of muscle coordination vary with terrain during locomotion BLAKE, OM*; FORSMAN, K; WAKELING, JM; Simon Fraser University, Burnaby; Simon Fraser University, Burnaby; Simon Fraser University, Burnaby omb@sfu.ca

Patterns of muscle coordination have been well studied in laboratory settings, yet conclusions and correlations to outdoor environments are limited by the ability of laboratory studies to recreate realistic variations in terrain. Few studies have ventured into the field to investigate how muscle coordination varies in a more natural setting. The purpose of this study is to identify correlations between muscle activation patterns and factors known to affect muscle coordination in the field. To accomplish this muscle activity was measured in human subjects while cycling outdoor on paved roads. Subjects cycled 20km (4 laps of 5km) in the shortest time possible. Muscle activity of 8 leg muscles was continuously recorded using surface electromyography (EMG) while power output, cadence, heart rate and rider location were recorded. The time-varying intensity of the EMG signals was calculated and the dominant coordination patterns were identified using principal components analysis. Coefficients for muscle coordination were statistically compared to the mechanical power output, cycle frequency, velocity, heart rate, course slope and lap number using analysis of covariance. The muscle coordination patterns significantly covaried with the power output, cycle frequency, heart rate, course slope and lap number. These results show that muscle coordination changes with altered locomotor demands and terrain, and highlights the importance of recording these parameters under field conditions.