Is coordination variability using vector coding different in overground and treadmill walking and running?

Background: Coordination variability has been linked to overuse running injuries and has been studied both on a treadmill and over-ground. It is not clear, however, if the coordination variability data from over-ground locomotion can be compared with treadmill locomotion data.& nbsp;Research question: Therefore, the purpose of this study was to compare coordination variability of selected lower extremity couplings at different locomotor speeds during over-ground and treadmill walking and running.& nbsp;Methods: Nineteen (10 female, 9 male) healthy, recreational collegiate runners participated in this study. Each participant performed in two different conditions: over-ground and on a treadmill at three walking speeds (1.2, 1.6, and 2.0 m?& nbsp;s(-1)) and three running speeds (2.8, 3.2, and 3.6 m?& nbsp;s(-1)). A modified vector coding technique was used to calculate coordination variability for five selected coupled segment and joint angles. Each of the segmental couples was analyzed separately using a two-way repeated measures ANOVA (Condition X Speed) implemented with one-dimensional statistical parametric mapping.Results: While no interaction effects were observed for condition X speed, we saw increased coordination vari-ability in the sagittal couples during overground compared with treadmill locomotion, which predominantly occurred during the stance phase. There were mixed results for changes in coordination variability as a function of gait speed. However, for the sagital plane couplings, coordination variability decreased with speed, particu-larly during the stance phase.& nbsp;Significance: These results suggest that the controlled belt speed of the treadmill affects the intrinsic dynamics of human movement and this should be considered when making comparisons between treadmill and over-ground studies and in future study designs.

Automated summary

This study compared coordination variability during over-ground and treadmill walking and running at different speeds. The results showed that coordination variability was higher during over-ground locomotion compared to treadmill locomotion. Additionally, coordination variability decreased with speed, particularly during the stance phase in the sagittal plane.