Physical activity, muscle quality, and reactive balance control in community-dwelling older adults

Abstract

Falls are a leading cause of injury, disability, and mortality among older adults, yet existing fall prevention strategies have not effectively reduced fall rates. Despite widespread recommendations promoting general physical activity and conventional balance training, falls and fall-related deaths continue to increase. One potential reason for this limited success is that conventional interventions primarily focus on proactive balance control and functional capacity, while most falls arise from unexpected perturbations that necessitate rapid reactive balance responses. Perturbation-based balance training (PBT) has emerged as a promising strategy to improve reactive balance control and lower fall risk, but its feasibility, effectiveness, and broader implementation remain insufficiently explored. Through three studies, this dissertation investigated key factors contributing to fall risk and balance recovery in older adults. Study 1 examined whether habitual physical activity and conventional functional assessments can predict future falls in community-dwelling older adults. Results showed no significant association, suggesting that traditional measures may not adequately capture the neuromuscular mechanisms crucial for fall prevention. Study 2 explored the link between lower limb muscle quality and balance recovery, finding that biceps femoris muscle quality was related to improved reactive balance responses. This preliminary evidence underscores the potential role of muscle composition in assessing fall risk. Study 3 evaluated the acceptability and feasibility of a community-based PBT program, revealing that while older adults and healthcare providers regarded PBT as beneficial, cost and accessibility posed barriers to widespread adoption. Collectively, these findings reinforce the need for a paradigm shift in fall prevention, emphasizing targeted assessments and interventions that specifically enhance reactive balance control. Future research should focus on refining assessment tools, optimizing PBT protocols, and developing cost-effective methods for integrating reactive balance training into clinical and community settings. Addressing these gaps is essential for advancing fall prevention strategies and improving outcomes for older adults at risk of falls.