Short and long term adaptation of variability during walking using unstable (Mbt) shoes

Background: The purpose of the study was to compare the variability of biomechanical variables during treadmill walking using unstable shoes (Masai Barefoot Technology, MBT, Roggwil, Switzerland) and conventional shoes, before and after a 10 week (wk) training period. Methods: Cycle characteristics, plantar pressure distribution, whole body 3D kinematics, and electromyographic signals of selected leg muscles during ground contact were recorded on 12 Sport Science students while walking on a treadmill with both conventional and unstable shoes before and after a 10 wk training intervention. The intervention consisted of more than 4 h use of unstable shoes during daily activity. The standard deviation of 15 consecutive cycles in each analyzed variable was taken as the measure for variability. Findings: The main pattern was marked by a 35% (SD 10%) higher variability with the unstable shoes at pretest when compared with the conventional shoes, but decreased 30% (SD 12%) (both P<0.05) during the training intervention to almost equal variability in between the two shoe situations. This was especially true with regard to variables representing within gait characteristics (peak foot force, joint angles, etc.), whereas in variables describing the overall gait cycle (e.g. cycle rate, impulse of total force, etc.) no difference between MBT and conventional shoes at pre and post tests were found. Interpretation: The current study supports the idea that the unstable shoe serves as a motor constraint applicable during everyday activity, provoking increased variability during walking. In addition, a decrease in movement variability on the MBT shoes during the training intervention to the level of conventional shoes was observed. (C) 2010 Elsevier Ltd. All rights reserved.