Four-Meter Gait Speed: Normative Values and Reliability Determined for Adults Participating in the NIH Toolbox Study

Objectives: To establish reference values and determine test-retest reliability for usual and maximal 4-meter gait speed. Design: Cross-sectional observational study. Setting: Offices in 10 geographically dispersed cities in the United States. Participants: Men and women (N=1320), aged 18 to 85 years, enrolled in the National Institutes of Health Toolbox forming study. Intervention: Not applicable. Main Outcome Measures: Specifically used were data from men and women who were timed over 4 meters (after a static start) while walking at their usual and maximum speeds. Norms for usual and maximum gait speed were derived using data from 1320 participants. Test-retest reliability for 164 participants was described using paired t tests, intraclass correlation coefficients (ICCs), and minimal detectable changes (MDCs). Results: Mean usual speed was 1.12 meters per second, whereas mean maximum speed was 1.61 meters per second. As a general linear model showed 4-meter gait speed to differ significantly according to gait condition (speed), sex, and age group; estimates of normal were calculated accordingly. The usual speed of 80- to 85-year-old women was lowest at 0.95 meters per second; the maximum speed of 18- to 29-year-old men was highest at 1.85 meters per second. Test-retest measures did not differ significantly, but the ICCs were only fair and the MDCs were high. Conclusions: Normative reference values provided herein may be helpful in interpreting measurements of 4-meter gait speed obtained from adult men and women. The limited reliability of the gait speed measurements, however, limits their usefulness in making judgments regarding change. (C) 2018 by the American Congress of Rehabilitation Medicine