Differences in Reactive Muscle Recruitment Between Standing and Sit-to-Stand Perturbations

Alyssa H. Reeves* and Jessica L. Allen

Neuromechanics of Mobility Lab, Department of Chemical and Biomedical Engineering, West Virginia University, Morgantown, WV 26505

Presentation Category: Physical Sciences & Engineering (Poster Presentation #144)

Student’s Major: Biomedical Engineering

When standing or walking in day-to-day life, our bodies keep us balanced. Sometimes the disturbance in our balance is too great, causing us to stumble and we have to recruit our muscles to prevent a fall to the ground. How we should recruit our muscles depends on how off-balance the stumble puts us and what we were doing when we stumbled. We can examine the relationship between these stumbles and muscle recruitment in a controlled manner by perturbing people in the lab. In this study, we focused on perturbations while standing and arising from a chair (or sit-to-stand) that made people stumble forwards. The question we seek to answer in this study is: what are the differences between the two in terms of the muscles that prevent a fall? We analyzed three young, healthy subjects from a previously collected dataset that included muscle activity recorded from four muscles on the front and back of the lower leg. Using MATLAB, we calculated reactive muscle recruitment, or RMR, which is the muscle activity immediately following the perturbation. Our preliminary results demonstrate that Lateral Gastrocnemius was recruited the most after standing perturbations and Vastus Lateralis has significantly less activity in the sit-to-stand perturbations, with all muscle activity increasing as the stumble difficulty increased. This study will help us understand how we stay balanced depending on the situation and help us target a specific muscle if a patient is struggling with gait or arising from a chair.

Funding:

Program/mechanism supporting research/creative efforts: WVU's Research Apprenticeship Program (RAP) & accompanying HONR 297-level course