The Merit of an Individual Calibration: Estimating Physical Activity Energy Expenditure in Wheelchair Users

INTRODUCTION: The use of multi-sensor devices, which integrate accelerometry and physiological signals to predict PAEE, is widespread in able-bodied humans. However, the validity of such devices remains to be established in wheelchair users. The aim of this study is to assess the error of a multi-sensor physical activity monitor to predict PAEE in wheelchair users and to assess the efficacy of individual heart rate calibration. METHODS: Seventeen manual wheelchair users (36±10 yrs, 72±11 kg) completed an activity of daily living and wheelchair propulsion at various velocities and gradients on a motorised wheelchair treadmill. Participants wore a combined accelerometer and heart rate monitor (ActiheartTM). Heart rate was also monitored during an incremental arm crank ergometer test to permit retrospective individual calibration of the ActiheartTM for the activity protocol. Linear regression analysis was conducted between criterion (indirect calorimetry) and estimated PAEE from the ActiheartTM using manufacturers proprietary algorithms or individual calibration. Subsequent error statistics were calculated. RESULTS: Predicted PAEE was significantly (p