Movement strategies for transferring without falling in older people

Falls are the leading cause of injury-related hospitalizations among seniors and a major cause of disability and death. About 30 percent of people over age 65, and 50 percent of older people in residential care, experience at least one fall per year. The risk for falls is mediated by various physiological, behaviour and environmental factors, but ultimately depends on the frequency of imbalanced events and abilities to successfully recover balance.

One of the most essential and fall-prone activities for older people is transitioning from sitting to standing. Even though imbalance occurs frequently during transfers, not all transfers result in falls. Our understanding of what determines the success of sit-to-stand transfers is limited. This project will use video and wearable sensor technology to clarify environmental and biomechanical differences between successfully and unsuccessfully performed sit-to-stand movements in older people as they go about their daily activities. In complementary experiments, the project will examine the role of muscle power as an underlying mechanism for successful transferring.

This project has two objectives:

1. Quantify the importance of avoiding imbalance vs. recovery of balance in sit-to-stand transfers.
2. Identify the importance of muscle power for sit-to-stand performance in older people.

Objective 1 – Our research group is involved with an ongoing collection of video footage and wearable sensor data of mobility and falls in older people in long-term care. This project will contrast successful vs. unsuccessful transfers (resulting in falls) in individuals to identify strategies to prevent imbalance and attempts to recover balance (e.g. through muscle torque generation or through change in support, stepping and grasping). It will further quantify biomechanical characteristics of recovery attempts (e.g. size, direction and timing). This analysis will provide new ecological insight on the importance of avoiding imbalance vs. successfully recovering balance for older people prone to falls when transferring.

Objective 2 – The ability to plan and execute movements is a complex process that relies on sensory, cognitive and neuromuscular systems. This project will test the hypothesis that speed modulation is a key determinant of success for the task of rising from sitting, and that speed modulation will relate to lower limb power — a target amenable to improvement through exercise. These findings will contribute to current knowledge by identifying the key muscle functions for rising from sitting, to guide the development of a personalized intervention for those individuals at high risk for falling during transfers.

This project will ultimately provide key information on the cause and prevention of mobility impairments and falls in older people.