Activity-Monitor Accuracy in Measuring Step Number and Cadence in Community-Dwelling Older Adults

Abstract

The primary purpose of this study was to investigate the accuracy of theactivPAL physical activity monitor in measuring step number and cadence in older adults. Two pedometers (New-Lifestyles Digi-Walker SW-200 and New-Lifestyles NL-2000) used in clinical practice to count steps were simultaneously evaluated. Observation was the criterion measure. Twenty-one participants (65-87 yr old) recruited from community-based exercise classes walked on a treadmill at 5 speeds (0.67, 0.90, 1.12, 1.33, and 1.56 m/s) and outdoors at 3 self-selected speeds (slow, normal, and fast). The absolute percentage error of theactivPAL was <1% for all treadmill and outdoor conditions for measuring steps and cadence. With the exception of the slowest treadmill speed, the NL-2000 error was <2%. The SW-200 was the least accurate device, particularly at slower walking speeds. TheactivPAL monitor accurately recorded step number and cadence. Combined with its ability to identify primary postures, theactivPALmight be a useful and versatile device for measuring activity in older adults.