Differences of Physical Functions and Gait Kinematics in Selection of Strategies for Increasing Gait Speed in Older Adults: A Cross-sectional Study.

Objectives: This cross-sectional study aimed to examine the differences among strategies for improving gait speed, gait kinematics, and physical function in community-dwelling older adults. Methods: This study included 383 community-dwelling older adults. Spatiotemporal and kinematic gait parameters during preferred and fast walking were measured using inertial measurement units. Participants were classified into three groups based on the differences in step length and time between preferred and fast walking: time group (primarily decreasing step time), length group (primarily increasing step length), and intermediate group (intermediate strategies between time and length groups). The five-times sit-to-stand test was performed to assess lower-limb function. Two-way analysis of variance was conducted to compare physical functions and gait parameters between groups (time, intermediate, and length groups) and walking conditions (preferred and fast). Results: No significant interaction effect of group and sex was found for strategies for increasing gait speed (P = 0.875). The length group showed lower preferred and fast walking speeds (P <0.001) and longer sit-to-stand time (P = 0.006) than the time group. The length group also showed smaller trailing limb angle (defined by the location of the ankle joint relative to the hip joint in the sagittal plane) and smaller ankle plantar flexion angle at the pre-swing phase during preferred walking than the time group (P = 0.002). Conclusions: Strategies for increasing gait speed differed depending on lower-limb function and gait kinematics during preferred walking. These findings provide direction for the implementation of tailored gait interventions to prevent a decline in gait speed in older adults.