Accelerometer use in young people with Down syndrome: A preliminary cross-validation and reliability study

ABSTRACT

Background Inadequate physical activity is a problem for people with Down syndrome and objective monitoring using accelerometers may be inaccurate in this population.

Method This was a cross-validation and reliability study comparing two triaxial accelerometers (the SenseWear and RT3) to a criterion measure (the OxyCon Mobile) in 10 young people (M age = 20 ± 2) with Down syndrome. A ROC curve analysis was conducted to determine intensity thresholds from RT3 activity counts.

Results During self-selected pace walking, the accelerometers overestimated energy expenditure and had large limits of agreement (SenseWear: −0.5–3.6 METs; RT3: −0.2–2.7 METs). At this pace, SenseWear armband step counts were highly correlated with observed steps (r = .98) but underestimated steps by up to 12%. We developed RT3 thresholds that demonstrated good to excellent sensitivity and specificity in classifying physical activity intensity.

Conclusions SenseWear steps and RT3 activity count thresholds can be used to monitor physical activity in young people with Down syndrome, although energy expenditure estimates should be used with caution in this population.

KEYWORDS:

• Down syndrome
• accelerometry
• motor activity
• trisomy 21
• intellectual disability

Acknowledgements

The authors would like to acknowledge Julie Bernhardt (Florey Institute of Neuroscience and Mental Health, Melbourne, Australia) and Bo Fernhall (University of Illinois, Chicago, United States) for their contributions to the study protocol.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was funded by the La Trobe University Physical Activity and Rehabilitation research group, Faculty of Health Science, La Trobe University, Melbourne, Australia. This group did not impose any restrictions on free access to, or publication of, the research data.