Objectives: Standardized tests of gait speed are regarded as being of clinical value, but they are typically performed under optimal conditions, and may not reflect daily-life gait behavior. The aim of this study was to compare 4-m gait speed to the distribution of daily-life gait speed. Study design: The cross-sectional Grey Power cohort included 254 community-dwelling participants aged 18 years or more. Main outcome measures: Pearson's correlations were used to compare gait speed assessed using a timed 4-m walk test at preferred pace, and daily-life gait speed obtained from tri-axial lower-back accelerometer data over seven consecutive days. Results: Participants (median age 66.7 years [IQR 59.4–72.5], 65.7% female) had a mean 4-m gait speed of 1.43 m/s (SD 0.21), and a mean 50th percentile of daily-life gait speed of 0.90 m/s (SD 0.23). Ninety-six percent had a bimodal distribution of daily-life gait speed, with a mean 1st peak of 0.61 m/s (SD 0.15) and 2nd peak of 1.26 m/s (SD 0.23). The percentile of the daily-life distribution that corresponded best with the individual 4-m gait speed had a median value of 91.2 (IQR 75.4–98.6). The 4-m gait speed was very weakly correlated to the 1st and 2nd peak (r = 0.005, p = 0.936 and r=0.181, p = 0.004), and the daily-life gait speed percentiles (range: 1st percentile r = 0.076, p = 0.230 to 99th percentile r = 0.399, p < 0.001; 50th percentile r = 0.132, p = 0.036). Conclusions: The 4-m gait speed is only weakly related to daily-life gait speed. Clinicians and researchers should consider that 4-m gait speed and daily-life gait speed represent two different constructs.
van Ancum, J. M., van Schooten, K. S., Jonkman, N. H., Huijben, B., van Lummel, R. C., Meskers, C. G. M., ... Pijnappels, M. (2019). Gait speed assessed by a 4-m walk test is not representative of daily-life gait speed in community-dwelling adults. Maturitas, 121, 28-34. https://doi.org/10.1016/j.maturitas.2018.12.008