Impact of Age and Surface on Lower Limb Muscle Activity During Walk and Pivot Tasks
Dr. Tyler Brown
Introduction: Muscular strength decreases with age leading to changes in lower limb muscle activity, such as increased agonist and antagonist co-contraction, during gait task older adults (over 65 years). External perturbations, including cognitive distraction and slick surface, challenge the central nervous system, resulting in muscle activity alterations to safely walk. Yet, it is unclear whether older adults exhibit greater alterations in muscle activity than young adults during gait task with challenging perturbations.
Purpose: To quantify the effects of age and challenging perturbations (both distraction and slick surface) on lower limb muscular activity.
Methods: Twenty-nine (16 young – 18 to 25 years and 13 older – over 65 years) adults had lower limb muscle activity quantified while they walked and pivoted with and without external perturbations (i.e., cognitive distraction and/or slick surface). Then, average lower limb muscle re-activity and thigh co-contraction index (CCI) were calculated for the walk and pivot tasks and submitted to a repeated measures ANOVA analysis.
Results: During the walk, each muscle and co-contraction index exhibited a significant distraction by surface interaction (all: p < 0.041), muscle activity decreased on both surfaces when distracted, and on the slick compared to normal surface with and without the distraction. Older adults exhibited greater lateral hamstring activity (p = 0.048) during the walk. During the pivot, a significant distraction by age interaction was observed for tibialis anterior activity (p = 0.041), as young adults decreased activity when distracted. Also during the pivot, both tibialis anterior (p=0.010) and the lateral gastrocnemius (p=0.026) activity decreased when distracted, and lateral gastrocnemius (p=0.026), vastus lateralis (p=0.007), and lateral hamstring (p=0.030) decreased on the slick surface. Older adults exhibited greater tibialis anterior (p = 0.004) and lateral gastrocnemius (p= 0.019) during the pivot task.
Conclusion: Participant decreased lower limb muscle activity with the addition of challenging perturbation (both slick surface and cognitive distraction). But, the challenging perturbation did not further alter older adults muscle activity.
Robinett, Matthew; Brown, Tyler; and Hunt, Nicholas, "Impact of Age and Surface on Lower Limb Muscle Activity During Walk and Pivot Tasks" (2022). 2022 Undergraduate Research Showcase. 77.