The impact of pedal rate on muscle oxygenation, muscle activation and whole-body VO2 during ramp exercise in healthy subjects

Purpose The aim of this project was to study the impact of pedal rate on breakpoints in muscle oxygenation (deoxy[Hb + Mb] and total[Hb + Mb]) and activation (iEMG and MPF) at high intensities during ramp exercise. Methods Twelve physically active students performed incremental ramp exercises at 60 rpm, starting either at 50 or 80 W (i.e., 60rpm50 and 60rpm80), and at 100 rpm, starting at 50 W (100rpm50). Pulmonary V O 2 , muscle activation (iEMG and MPF) and oxygenation were recorded with EMG and NIRS, respectively. IEMG, MPF, deoxy[Hb + Mb] and total[Hb + Mb] were expressed as functions of work rate (WR) and pulmonary V O 2 (% V O 2peak ) and analyzed with double-linear models. Results The breakpoints (BP) of iEMG, MPF, total[Hb + Mb] and deoxy[Hb + Mb] in % V O 2peak did not differ among the pedal rate conditions ( P > 0.05), whereas the BPs in WR were significantly lower in 100rpm50 compared to 60rpm50 and 60rpm80 ( P