Objectively Monitored Physical Activity and Time in Sedentary Behaviors: Association with Older Adults’ Gait Speed

Clinically assessed gait speed is a valuable test of older adults’ functioning and an important predictor of adverse outcomes including disability, cognitive decline, falls, institutionalization, and mortality. It is logical to pursue correlates of gait speed.

Purpose To evaluate the relationship between accelerometer-determined indicators of free-living walking volume (steps/day, activity counts/day), walking speed (steps and time spent at incrementally higher cadences, peak cadence indicators), and time spent in sedentary behavior with older adults’ usual gait speed.

Methods 148 older adults (71.6 ± 8.0 years of age) provided ≥ 3 valid days of accelerometer (GT3X+; ActiGraph LLC, Pensacola, FL) data (17.0 ± 2.5 hr/day of wear time) and GAITRite-assessed gait speed. Spearman correlation coefficients described associations between these data. Partial correlations controlled for age and BMI. Linear regression was used to determine optimal steps/day associated with 0.05 m/s (small) and 0.1 m/s (substantial) differences in gait speed.

Results Nearly all accelerometer-determined movement variables were significantly associated with gait speed, however, of all considered, steps/day had the strongest and most consistent relationship with gait speed (Spearman r = 0.562-0.578, partial r = 0.392-0.414, p < 0.001). There was evidence to suggest that the relationship (r=0.609) was stronger when focused on time spent at a cadence of 20+ steps/min compared to time spent at any cadence above zero (r=0.442). 1,100 steps/day and 2,200 steps/day were associated with 0.05 m/s and 0.1 m/s differences in gait speed, respectively. There was no relationship between time in sedentary behaviors and gait speed.

Conclusions These cross-sectional data suggest that strategies to improve gait speed among older adults include walking more, and specifically replacing at least some of the abundant amount of time spent in sedentary behaviors and incidental movement with more purposeful ambulation.