Details

Autor(en) / Beteiligte

• Boone, Jan
• Barstow, Thomas J.
• Celie, Bert
• Prieur, Fabrice
• Bourgois, Jan

Titel

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

Ist Teil von

• European journal of applied physiology, 2015-01, Vol.115 (1), p.57-70

Ort / Verlag

Berlin/Heidelberg: Springer Berlin Heidelberg

Erscheinungsjahr

2015

Quelle

MEDLINE

Beschreibungen/Notizen

• 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  < 0.01). Across the pedal rate conditions the BP (in % V O 2peak ) of total[Hb + Mb] (82.7 ± 1.5 % V O 2peak ) was significantly lower ( P  < 0.01) compared to the BP in iEMG (84.3 ± 1.7 % V O 2peak ) and MPF (84.2 ± 1.6 % V O 2peak ), whereas the BP in deoxy[Hb + Mb] (87.4 ± 1.4 % V O 2peak ) and respiratory compensation point (89.9 ± 1.8 % V O 2peak ) were significantly higher ( P  < 0.01) compared to the BP in total[Hb + Mb], iEMG and MPF. Additionally, the BPs in iEMG, MPF, total[Hb + Mb] and deoxy[Hb + Mb], and the RCP were highly correlated ( r  > 0.90; P  < 0.001). Conclusions The present study showed that muscle activation and oxygenation at high intensities during incremental exercise are related to pulmonary V O 2 rather than external WR, with a close interrelationship between that muscle activation, oxygenation and pulmonary V O 2 .