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.
Keywords: autism spectrum disorder; exercise; lower extremity; proprioception; sensorimotor feedback.