Use of Self-Organizing Maps for Exploring Coordination Variability in the Transition Between Walking and Running

Abstract

This study investigated multi-dimensional coordination instability and variability in the transitions between walking and running for a 26 year old female runner using self-organizing maps (SOMs) in three experimental procedures. We found different multi-dimensional coordination patterns for walking and running using the output from SOMs as stride trajectories on U-matrices and attractor diagrams. In transient conditions, the participant showed multi-stability, or instability, in the transition region for decreasing but not for increasing speeds. She also clearly showed increased multi-dimensional coordination variability around the transition region only for decreasing speeds and only in transient conditions. These findings may not be general across runners nor were they conclusive enough to support variability as a facilitator of the change from running to walking. Self-organizing maps provide us with a tool to study multi-dimensional coordination (and coordination variability) and to reduce its complexity to relatively simple map outputs, including basins of attraction and attractor landscapes.