Running Biomechanics of Adolescents With Autism Spectrum Disorder

Are Gait Biomechanics Related to Physical Activity Engagement? An Examination of Adolescents with ASD

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 years) with ASD and seventeen 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. 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 (LPA), moderate to vigorous (MVPA), and total PA was recorded for the entire dataset with ASD using triaxial accelerometers worn for one week. 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 to the controls (p=0.016). Speed and stride length were significant regressors of LPA, MVPA, and total PA, explaining greater than 0.20 variance (p<0.02 for all regressions).

CONCLUSION

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.

Lower Limb Proprioception and Strength Differences Between Adolescents With Autism Spectrum Disorder and Neurotypical Controls

Autism spectrum disorder (ASD) is a complex diagnosis characterized primarily by persistent deficits in social communication/interaction and repetitive behavior patterns, interests, and/or activities. ASD is also characterized by various physiological and/or behavioral features that span sensory, neurological, and neuromotor function. Although problems with lower body coordination and control have been noted, little prior research has examined lower extremity strength and proprioception, a process requiring integration of sensorimotor information to locate body/limbs in space. We designed this study to compare lower limb proprioception and strength in adolescents with ASD and neurotypical controls. Adolescents diagnosed with ASD (n = 17) and matched controls (n = 17) performed ankle plantarflexion/dorsiflexion bilateral proprioception and strength tests on an isokinetic dynamometer. We assessed position-based proprioception using three targeted positions (5 and 20-degrees plantarflexion and 10-degrees dorsiflexion) and speed-based proprioception using two targeted speeds (60 and 120-degrees/second). We assessed strength at 60-degrees/second. Participants with ASD performed 1.3-times more poorly during plantarflexion position and 2-times more poorly during the speed-based proprioception tests compared to controls. Participants with ASD also exhibited a 40% reduction in plantarflexion strength compared to controls. These findings provide insight into mechanisms that underly the reduced coordination, aberrant gait mechanics, and coordination problems often seen in individuals with ASD, and the identification of these mechanisms now permits better targeting of rehabilitative goals in treatment programs.