Coordination variability during overground, treadmill and treadmill-on-demand running

The purpose of this study was to investigate differences in lower extremity coordination variability between overground, treadmill and treadmill-on-demand running. A modified normalised root mean square difference technique was used to quantify the variability in lower extremity coordination calculated from the kinematic data collected during ten strides of overground, treadmill and treadmill-on-demand running at 3.5 m.s". Although no significant differences were observed between the two types of treadmill, significantly reduced (p < 0.02) coordination variability was seen in the treadmill and treadmill-ondemand conditions compared to overground locomotion. Therefore, a constant belt speed during treadmill locomotion does not account for the differences seen between overground and treadmill running and further work is required to determine factors that cause the difference.