Age-related changes in multi-behavioral reactive balance control

项目总结

PROJECT SUMMARY Our long-term goal is to advance knowledge on age-related changes in the multi-behavioral sensorimotor control of balance leading to falls in older adults to guide the development of more effective treatments and rehabilitation for improving balance. Despite conventional diagnostic and rehabilitative efforts, our rapidly aging population remains at a high risk of debilitating falls. These falls can occur in a variety of different movement behaviors important for daily life, including standing, arising from a chair, and walking. When a loss of balance occurs during any of these movement behaviors, muscles must be reactively recruited to return the body upright in order to prevent a fall. How muscles should be recruited depends on the size of the balance loss (e.g., small versus large) and what a person is doing when the balance loss occurs (e.g., standing versus walking). How the modulation of reactive muscle recruitment is affected by aging and associated with risk of falling is unknown. As a first step towards our long-term goal, the objective of the proposed project is therefore to identify changes in reactive muscle recruitment across several movement behaviors in which falls often occur in older adults – standing, sit-to-stand, and walking. To investigate changes in reactive muscle recruitment, we will experimentally impose balance loss through discrete translations of the support surface (i.e. perturbation) during each of these movement behaviors while measuring muscle activity using electromyography from a group of young adults, older adults, and older adults with a history of falling. In Specific Aim 1, we will investigate how scaling of reactive muscle recruitment is altered due to aging and a history of falls. Scaling refers to the ability to modulate reactive muscle recruitment within a single movement behavior to the size of the perturbation (e.g., larger perturbations require higher levels reactive muscle recruitment to prevent a fall). Scaling will independently be investigated in standing, sit-to-stand, and walking by exposing subjects to various levels of perturbation difficulty. In Specific Aim 2, we will investigate how the tuning of reactive muscle recruitment is altered due to aging and a history of falls. Tuning refers to the ability to modulate reactive muscle recruitment across different movement behaviors (e.g., how ankle muscles should be recruited depends on if the loss of balance occurs in standing versus walking). Tuning will be investigated by examining the differences in reactive muscle recruitment across each of the three movement behaviors. The outcomes of this project will enhance our fundamental understanding regarding changes in multi- behavioral reactive muscle recruitment due to aging that are associated with fall history – changes which could serve as targets for rehabilitation interventions to improve balance. In addition, the proposed project will also provide undergraduate students at WVU training opportunities in biomechanics and motor control research, providing a strong basis for their success in their future research careers.