Grant: Travel Awards - Institute Community Support

Introduction: The variability of movements during walking is linked to fall risk in aging males and females. Currently, the source of this variability is unclear. One potential source is the variability of the muscle patterns, as these muscle patterns produce the movements involved in walking. However, the influences of older age and sex on the variability of muscle patterns during walking is unknown; this information could help understand how falls occur in aging males and females. Methods: Males and females aged 20 to 82 years walked over a platform at their preferred speed. These participants wore electrical sensors over several lower limb muscles to measure their muscle patterns. The variabilities of these patterns, from stride-to-stride, were calculated; these muscle pattern variabilities were then analyzed using statistical models to test how they were influenced by older age and sex. Results: Older age was generally associated with higher muscle pattern variability in males and females, except for the single leg support phase of walking. During this phase, older age was associated with lower muscle pattern variability in females only. Conclusions: There were both sex-independent and sex-dependent influences of older age on the variability of muscle patterns. The sex-dependent influence points towards less flexibility in how aging females, when compared to males, stabilize their ankle during the single leg support phase of walking. This may help explain the sex difference in fall risk of aging adults.