Medicine and Science in Sports and Exercise · Oct 19, 2016

Evaluating Walking Intensity with Hip-Worn Accelerometers in Elders

By Corbett DB, Valiani V, Knaggs JD et al.

PURPOSE: Accelerometer activity counts are used to objectively categorize physical activity levels. We examined the association between accelerometer activity counts and metabolic effort in older adults. METHODS: Forty-five older adults (76.3 ± 5.1 yr) completed a 400-m walk at both a usual and a rapid pace. A portable metabolic unit measured pulmonary gas exchange, whereas a hip-worn accelerometer measured activity counts. Participants were categorized as either a "slow walker" or a "fast walker" based on the threshold of 1.0 m·s during usual-pace walking. RESULTS: Activity counts during rapid (r = 0.62, P < 0.01) but not usual-pace (r = 0.24, P = 0.11) walking were significantly associated with METs. Slow walkers attained only half the activity counts of fast walkers during each walk condition (P < 0.01), while at the same time achieving between 82% and 90% of their MET level. CONCLUSION: Accelerometers may misclassify the activity level of functionally impaired older adults with slow walking speed.

doi.org/10.1249/mss.0000000000001018PubMed 27327031Biomarkers