Oxygen consumption during constant-load exercise - Heterogeneity of quadriceps muscle oxygen consumption during submaximal constant-load dynamic cycling

Introduction: There have been a lot of studies examining all aspects of whole body oxygen consumption (pVO2), but when it comes to what happens on a local level, there is still a lot that is unexplored. The aim of this study is to expand on the area that is heterogeneity of local muscle oxygen consumption (mVO2) using near-infrared spectroscopy (NIRS) as the measurement tool and a cycle ergometer as the exercise device. Methods: Using 15 trained cyclists to measure mVO2 at rest and at three different intensities in 3 different muscles, vastus lateralis, vastus medialis, and rectus femoris at once using an 8-channel NIRS setup. Results: Heterogeneity was found in various circumstances both between muscles and within muscles. Statistical tests showed that the participants were a homogeneous group. Discussion: Vastus lateralis and vastus medialis was heterogeneous at low intensity, but at this difference was lower at the highest intensity of 250 Watts. Conclusion: This is one of the first studies using an 8-channel NIRS setup to examine the oxygenation of quadriceps. There might be a displacement with NIRS on the rectus femoris muscle. Keywords: pVO2, NIRS, mVO2, Vastus Lateralis, Vastus Medialis, Rectus Femoris, heterogeneity, cycle ergomete