Are Gait Biomechanics Related to Physical Activity Engagement? An Examination of Adolescents with Autism Spectrum Disorder.

Purpose: Adolescents with autism spectrum disorder (ASD) rarely meet physical activity (PA) guidelines, thus not reaping associated health benefits. Although many barriers exist, abnormal or inefficient gait biomechanics could negatively impact engagement in PA. This study has two purposes: first, to compare total body mechanical work between adolescents with ASD and neurotypical age-, sex-, and body mass index-matched controls, and second to determine whether gait biomechanics are significantly related to engagement in PA.

Methods: Twenty-five adolescents (age, 13-18 yr) with ASD and 17 neurotypical controls (eight with ASD had no match) participated in the study. Three-dimensional motion capture and force platforms were used to record and analyze gait biomechanics at self-selected speeds and a standardized 1.3 m·s-1. Total body mechanical work (sum of joint works across lower extremity, low back, torso, and shoulders) was compared between groups (n = 17 for each) and speeds using a mixed model analysis of variance. Average daily light PA, moderate to vigorous PA, and total PA was recorded for the entire data set with ASD using triaxial accelerometers worn for 1 wk. Regression analyses were performed between work, stride time variability, speed, and stride length with each PA variable.

Results: Adolescents with ASD generated 9% more work compared with the controls (P = 0.016). Speed and stride length were significant regressors of light PA, moderate to vigorous PA, and total PA, explaining greater than 0.20 variance (P < 0.02 for all regressions).

Conclusions: Although adolescents with ASD walked with significantly greater work, the complex full-body variable is not significantly related to engagement in PA. In agreement with research spanning multiple populations and ages, speed and stride length are indicative of PA engagement in adolescents with ASD.