Preliminary Field Validity of Free-Living Energy Expenditure Estimation in Wheelchair Users with Spinal Cord Injury via Wearable Device-based Models

Study Design Cross-sectional validation study. Objectives To develop a raw acceleration signal-based random forest (RF) model for predicting total energy expenditure (TEE) in manual wheelchair users (MWUs) and evaluate the preliminary field validity of this new model along with four existing models published in prior literature using the Doubly Labeled Water (DLW) method. Setting General community and research institution in Pittsburgh, USA. Methods A total of 78 participants’ data from two previous studies were used to develop the new RF model. A seven-day cross-sectional study was conducted to collect participants’ free-living physical activity and TEE data, resting metabolic rate, demographics, and anthropometrics. Ten MWUs with spinal cord injury (SCI) completed the study, with seven participants having valid data for evaluating the preliminary field validity of the five models. Results The RF model achieved a mean absolute error (MAE) of 0.59 ± 0.60 kcal/min and a mean absolute percentage error (MAPE) of 23.6%±24.3% on the validation set. For preliminary field validation, the five assessed models yielded MAE from 136 kcal/day to 1141 kcal/day, and MAPE from 6.1–50.2%. The model developed by Nightingale et al. in 2015 achieved the best performance (MAE: 136 ± 96 kcal/day, MAPE: 6.1%±4.7%), while the RF model achieved comparable performance (MAE: 167 ± 99 kcal/day, MAPE: 7.4%±5.1%). Conclusions: Two existing models and our newly developed RF model showed good preliminary field validity for assessing TEE in MWUs with SCI and the potential to detect lifestyle change in this population. Future large-scale field validation study and model iteration is recommended.