College of Education & Professional Studies (Darden)


Human Movement Sciences

Graduate Level


Graduate Program/Concentration

Applied Kinesiology

Publication Date





During late adolescence, children undergo rapid skeletal growth changes leaving the child more vulnerable to injury during physical activity. This is consistent for autistic youth, who reportedly enjoy individual activities, such as running, more than team-based sports [1-3]. Inadequate joint stiffness is one of several factors that may influence injury risk [4]. The purpose of this study was to examine lower extremity joint stiffness in autistic and non-autistic matched controls at self-selected and matched running speeds.

Twenty-two persons with a confirmed autism spectrum disorder (ASD) diagnosis and seventeen age, sex, and body mass index controls (CON) were enrolled into the study. Position and force data were collected in the Neuromechanics Laboratory using the motion capture system. Participants were asked to complete a series of over-ground running trials at their self-selected speed and a standardized speed of 3.0 m/s.

Joint stiffness was calculated as the quotient of the change in joint moment and the change in joint angle during the energy absorption period of stance. Statistical analyses were performed in SPSS (version 27, IBM Corp.). Stiffness and changes in joint moments were analyzed using 2 (group) x 2 (speed) analyses of variance.

There were no significant interactions between groups and speeds (p>0.05) for any variable. Persons with ASD had reduced knee and ankle joint stiffness (all p

Persons with ASD had reduced lower extremity stiffness, which was due to their reduced joint moments. Decreased joint stiffness by those with ASD could be indicative of a less efficient running style whereby the elastic recoil is not being optimally utilized.


Autism Spectrum Disorder, Joint Stiffness, Biomechanics, Running


Sports Sciences



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Lower Extremity Joint Stiffness During Running in Adolescents with Autism Spectrum Disorder