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Comment & Response
May 2017

Measuring Postconcussive Activity Levels of Patients: Step Count or Activity Intensity?

Author Affiliations
  • 1Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, United Kingdom
  • 2University of Idaho, Moscow
JAMA Pediatr. 2017;171(5):493-494. doi:10.1001/jamapediatrics.2017.0131

To the Editor Wiebe et al1 examined the relationships between physical activity and symptoms of patients following concussion. We have several methodological concerns.

First, this study used accelerometer-based step count to reflect physical activity level of patients. The validity of accelerometer-based step count has been questioned. For example, a particular model of accelerometer overestimated step count by 5265 steps per day in free-living condition.2 However, the model of accelerometer used in this study was not reported nor was the compliance rate (eg, mean wear/nonwear time per day), which may affect the validity of measurement.

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