Association between Daily Living Walking Speed and Walking Speed in Laboratory Settings in Healthy Older Adults.

Although there is evidence on the predictors of adverse health outcomes in older individuals, walking speed has typically been measured in laboratory settings (LWS); LWS may be distinct from individuals' actual walking speed in their daily lives (DWS). We examined whether DWS differs from LWS among older adults, and its association with physical frailty. Participants were 90 community-dwelling older adults. A five-meter normal (LWS) and maximum (LWS) walking speed was measured with a stopwatch. DWS was measured using a global positioning system-related smartphone application for one month during their daily lives. DWS, DWS, and DWS were defined as the average, maximum, and standard deviation of walking speed for one month. Participants' mean DWS and DWS were 1.28 m/s and 2.14 m/s, respectively, significantly slower than the mean LWS (1.42 m/s) and LWS (2.24 m/s); the intraclass correlation coefficient between DWS and LWS were 0.188 to 0.341. DWS was significantly correlated with grip strength, one-legged stance, and LWS. The area under the receiver operating characteristic curve of DWS concerning pre-frailty was largest among DWSs, at 0.615, while that of LWS was 0.643. The findings suggest that DWS differs from LWS and is associated with physical function and pre-frailty.