Physical activity measurement using MTI (actigraph) among children with cerebral palsy

Catherine Mamaid CAPIO, Cindy H. SIT, Bruce ABERNETHY

Research output: Contribution to journalArticlespeer-review

42 Citations (Scopus)


Objective: To investigate the validity of MTI accelerometer as a physical activity (PA) measurement instrument for children with cerebral palsy (CP). 

Design: Participants were classified within Gross Motor Function Classification System I to III and took part in 2 activity sessions: (1) a structured activity protocol with increasing intensities and (2) a free play session. Concurrent measurements of activity counts, heart rate, and observed physical activity were performed. 

Setting: Data were collected on normal school days in special schools within the participants' 30-minute break period. 

Participants: Convenience sample of children with CP (N=31; 17 girls, 14 boys) age between 6 and 14 years (mean ± SD, 9.71±2.52y). 

Interventions: Not applicable. 

Main Outcome Measures: MTI measured activity counts, a monitoring device measured heart rate, and the System for Observing Fitness Instruction Time (SOFIT) was used for direct PA observation. 

Results: There were strong relationships between MTI and SOFIT (r=.75; R2=.56; P<.001) and heart rate monitor (HRM) and SOFIT (r=.65; R2=.43; P<.001) data in structured activities, but the difference between these 2 correlation coefficients was not significant (P=.46). In free play activities, the association between MTI and SOFIT data (r=.67; R2=.45; P<.001) was significantly stronger (P=.01) than that between heart rate and SOFIT data (r=.14; R2=.02; P<.001) . Bland-Altman plots showed better agreement between observed SOFIT and MTI-predicted SOFIT data than observed SOFIT and HRM-predicted SOFIT data from the linear regression analysis. 

Conclusions: The findings suggest that the MTI appears to be a valid instrument for measuring raw activity volume among children with CP and is suitable for use in studies attempting to characterize the PA of this population. Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)1283-1290
JournalArchives of Physical Medicine and Rehabilitation
Issue number8
Publication statusPublished - Aug 2010


Capio, C. M., Sit, C. H., & Abernethy, B. (2010). Physical activity measurement using MTI (actigraph) among children with cerebral palsy. Archives of Physical Medicine and Rehabilitation, 91(8), 1283-1290. doi: 10.1016/j.apmr.2010.04.026


  • Cerebral palsy
  • Child
  • Heart rate
  • Rehabilitation


Dive into the research topics of 'Physical activity measurement using MTI (actigraph) among children with cerebral palsy'. Together they form a unique fingerprint.