The repeatability of gait speed and physiological cost index measurements in working adults.

Abstract

OBJECTIVES: To determine the performance characteristics of gait speed measurements and the physiological cost index (PCI; heart rate change/gait speed) in working adults. METHODS: Gait speeds, heart rate changes, and non-steady state PCIs were calculated in 61 volunteers who worked in our health sciences center. These subjects completed 9 separate 100-foot walk tests in 3 separate sessions. RESULTS: The mean heart rate change after a 100-foot walk was 16.6 ± 8.1 beats per minute. The mean gait speed was 76.1 ± 9.6 meters per minute, and the mean PCI was 0.22 ± 0.11 beats per meter. There were highly significant correlations among all measurements on the 9 separate tests (correlation coefficients 0.41-0.95); gait speed measurements had the highest correlations (0.91-0.95). In a multivariable model hypertension and arthritis were associated with reduced gait speeds. CONCLUSION: Gait speed, heart rate changes, and non-steady state PCIs have good repeatability when measured over short walks. This information provides a rapid physiological assessment and a method for measuring changes in functional status in healthy subjects and most patients.