Coordination variability during running in adolescents with autism spectrum disorder
Authors: Bennett Hunter J , Jones Taylor , Valenzuela Kevin A , Haegele Justin A 
Published: September 2021

Autistic persons exhibit variable movement, loading, and coordination patterns during walking. While much research has examined walking, little to no research exists regarding running for autistic persons despite its prevalence and benefits as a mode of physical activity. This study determined if autistic adolescents demonstrate increased coordination variability during running compared to matched controls. Seventeen autistic adolescents (aged = 13–18 years) and seventeen sex, age, and body mass index matched controls performed running at two matched speeds: self-selected of autistic adolescents and at 3.0 m/s. Modified vector coding was used to determine the patterns of movement for foot-shank, shank-thigh, left/right thigh, and contralateral arm-thigh coupling. Coordination variability, measuring cycle-to-cycle variability, was determined during loading response and pushoff phases. Mixed-model analyses of variance were used to determine group by speed interactions and main effects. Coordination variability was nearly 2× larger (all p < 0.001) in autistic adolescents compared to controls. Speed main effects were found for several sagittal plane couples during loading response. In agreement with walking analyses, this study illustrates that autistic adolescents run with increased intra-limb, inter-limb, and cross-body coordination variability. Like walking, increased coordination variability during running may negatively impact this mode of physical activity for autistic persons. Lay abstract Walking and running are popular forms of physical activity that involve the whole body (pelvis/legs and arms/torso) and are coordinated by the neuromuscular system, generally without much conscious effort. However, autistic persons tend not to engage in sufficient amounts of these activities to enjoy their health benefits. Recent reports indicate that autistic individuals tend to experience altered coordination patterns and increased variability during walking tasks when compared to non-autistic controls. Greater stride-to-stride coordination variability, when the task has not changed (i.e. walking at same speed and on same surface), is likely indicative of motor control issues and is more metabolically wasteful. To date, although, research examining running is unavailable in any form for this population. This study aimed to determine if coordination variability during running differs between autistic adolescents and age, sex, and body mass index matched non-autistic controls. This study found that increased variability exists throughout the many different areas of the body (foot-leg, left/right thighs, and opposite arm-opposite thigh) for autistic adolescents compared to controls. Along with previous research, these findings indicate autistic persons exhibit motor control issues across both forms of locomotion (walking and running) and at multiple speeds. These findings highlight issues with motor control that can be addressed by therapeutic/rehabilitative programming. Reducing coordination variability, inherently lessening metabolic inefficiency, may be an important step toward encouraging autistic youth to engage in sufficient physical activity (i.e. running) to enjoy physiological and psychological benefits.