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Updated: Jul 2, 2026
A Method for Quantifying Upper Limb Performance in Daily Life Using Accelerometers
Published on: April 21, 2017
Measuring free-living physical activity in adults with and without neurologic dysfunction with a triaxial
Leigh A Hale1, Jaya Pal, Ines Becker
1REAL Neurology Research Group, Centre for Physiotherapy Research and School of Physiotherapy, University of Otago, Dunedin, New Zealand. leigh.hale@otago.ac.nz
Objective:
To investigate the reliability, validity, and utility of a triaxial accelerometer to measure physical activity in the free-living environment in adults with and without neurologic dysfunction.
Design:
Repeated-measures design.
Setting:
General community.
Participants:
Volunteer sample of 17 men and 30 women (age range, 28-91y) living in the community with stroke of greater than 6 months in duration (n=20), Parkinson disease (n=7), or multiple sclerosis (n=11), and healthy but sedentary controls (n=9).
Interventions:
Not applicable.
Main Outcome Measures:
Physical activity measured with the TriTrac RT3 accelerometer, 7-day recall questionnaire, and activity diary.
Results:
The accelerometer reliably measured free-living physical activity (intraclass correlation coefficient, .85; 95% confidence interval, .74-.91; P=.000). The standard error of measurement indicated that a second test would differ from a baseline test by +/-23%. Mean daily RT3 data collected in the first 3 days differed significantly from that of the mean daily RT3 data collected over 7 days. The RT3 appeared to distinguish level of mobility better than the 7-day recall questionnaire, and participants found the RT3 to be a user-friendly and acceptable measure of physical activity.
Conclusions:
The triaxial accelerometer provided a stable measure of free-living physical activity, was found to distinguish between people with varying levels of mobility, and was well tolerated by participants. The results indicate that collecting data for 3 days was not reflective of data collected over 7 days.
