High Resolution MEMS Accelerometers to Estimate VO2 and Compare Running Mechanics between Highly Trained Inter-Collegiate and Untrained Runners

Abstract

The purposes of this study were to determine the validity and reliability of high resolution accelerometers (HRA) relative to VO₂ and speed, and compare putative differences in HRA signal between trained (T) and untrained (UT) runners during treadmill locomotion. Runners performed 2 incremental VO_2max trials while wearing HRA. RMS of high frequency signal from three axes (VT, ML, AP) and the Euclidean resultant (RES) were compared to VO₂ to determine validity and reliability. Additionally, axial rms relative to speed, and ratio of axial accelerations to RES were compared between T and UT to determine if differences in running mechanics could be identified between the two groups. Regression of RES was strongly related to VO₂, but T was different than UT (r = 0.96 vs 0.92; p<.001) for walking and running. During walking, only the ratio of ML and AP to RES were different between groups. For running, nearly all acceleration parameters were lower for T than UT, the exception being ratio of VT to RES, which was higher in T than UT. All of these differences during running were despite higher VO₂, O₂ cost, and lower RER in T vs UT, which resulted in no significant difference in energy expenditure between groups. These results indicate that HRA can accurately and reliably estimate VO₂ during treadmill locomotion, but differences exist between T and UT that should be considered when estimating energy expenditure. Differences in running mechanics between T and UT were identified, yet the importance of these differences remains to be determined.