Validation of a wireless device-driven method of estimating caloric expenditure during running.

Monitoring energy expenditure, such as VO2max, enables individuals to track their progress over time and can be used to guide training. Athletes are restricted to impractical wearable systems or smartwatches with high variable error rates. The device-driven model estimates caloric expenditure by using two wireless Inertial Measurement Units (IMUs). Our system uses off-the-shelf parts, each unit weighing 8.5 g with a total cost of $250. This was compared to the reference standard breath-by-breath respirometry during a maximal exercise protocol and found an average RMSE of 2.16 ± 1.50 W/kg. When the initial 180 s are excluded, the RMSE drops to 1.53 ± 0.97 W/kg indicating there may be a systematic bias present during the initial period of exercise. Validation of this device may provide individualized feedback in a wireless, affordable, and easy to use package.