METHODOLOGICAL ISSUES IN QUANTIFYING COORDINATION-VARIABILITY

Abstract

The aim was to investigate the effects of stride definitions on vector-coding for quantifying coordination-variability between the shank and rearfoot angles for strides extracted from heel-strike (HS) versus toe-off (TO) events. Subjects with chronic ankle instability were randomly assigned to control and balance-training groups (n=31). Three peaks of coordination-variability consistently existed near midswing, midstance and just before HS during treadmill walking at 1.32m/s. Variability only reduced near HS after balance training for the HS to HS stride definition (pre 0.45±0.14; post 0.34±0.12; P<0.05). The inconsistent findings with stride definitions may be owing to rapid changes in variability near HS that are sensitive to error sources and identification of stride events. Greater accuracy in extracting data is required to enhance the use of coordination-variability to explain movement.