Associations Between Fall Risk and Lower Limb Joint Range of Motion During Sit-to-Stand Among Community-Dwelling Older Adults.

INTRODUCTION: Despite the sit-to-stand transition being an acute period of increased fall risk among older adults, it is currently unclear how lower-limb joint range-of-motion (ROM) during this task relates to fall risk. METHODS: We examined 45 community-dwelling older adults (female = 32 (71.1%), age = 76.5±6.1years, BMI = 26.4±4.0kg/m2) within this cross-sectional study, assessing lower-limb mobility during 10 seconds of sit-to-stand repetitions using a single camera marker-less system. Hip and knee flexion, hip adduction, and ankle dorsiflexion were assessed for the right and left limbs, as well as asymmetry indices between sides. Fall risk was assessed using the STEADI checklist, Short Physical Performance Battery (SPPB), lower-body muscular power, postural sway, the Short Fall Efficacy Scale-International (FES-I), and 4-meter walking gait speed. Spearman's rho (ϱ) and Kruskal Wallis H-test were used due to nonnormal data distributions. RESULTS: High fall risk participants had significantly lower muscular power (2.8±0.6W/kg, p = 0.004, ε2 = 0.187) and higher knee flexion asymmetry (4.5±2.5°; p = 0.021, ε2 = 0.121) than low fall risk participants (3.6±1.0W/kg; 2.9±2.4°). All correlations between joint movements and fall risk assessments were relatively small/weak (ϱ ≤ |0.38|). Hip flexion asymmetries were significantly correlated with SPPB performance (ϱ = -0.33, p = 0.03) and Short FES-I scores (i.e., fear of falling; ϱ = 0.35, p = 0.02). CONCLUSIONS: Lower-limb ROM during the sit-to-stand transition may not be a strong indicator of fall risk on its own but may provide clinically relevant insight when paired with a validated fall risk assessment.