%0 Journal Article
%T Greater V步O2peak is correlated with greater skeletal muscle deoxygenation amplitude and hemoglobin concentration within individual muscles during ramp坼incremental cycle exercise
%A Dai Okushima
%A David C. Poole
%A Harry B. Rossiter
%A Narihiko Kondo
%A Shunsaku Koga
%A T. Scott Bowen
%A Tatsuro Amano
%A Thomas J. Barstow
%J Archive of "Physiological Reports".
%D 2016
%R 10.14814/phy2.13065
%X It is axiomatic that greater aerobic fitness ( V步 O2peak) derives from enhanced perfusive and diffusive O2 conductances across active muscles. However, it remains unknown how these conductances might be reflected by regional differences in fractional O2 extraction (i.e., deoxy [Hb+Mb] and tissue O2 saturation [StO2]) and diffusive O2 potential (i.e., total[Hb+Mb]) among muscles spatially heterogeneous in blood flow, fiber type, and recruitment (vastus lateralis, VL; rectus femoris, RF). Using quantitative time坼resolved near坼infrared spectroscopy during ramp cycling in 24 young participants ( V步 O2peak range: ~37.4每66.4 mL kgˋ1 minˋ1), we tested the hypotheses that (1) deoxy[Hb+Mb] and total[Hb+Mb] at V步 O2peak would be positively correlated with V步 O2peak in both VL and RF muscles; (2) the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) during submaximal exercise would not differ among subjects differing in V步 O2peak. Peak deoxy [Hb+Mb] and StO2 correlated with V步 O2peak for both VL (r = 0.44 and ˋ0.51) and RF (r = 0.49 and ˋ0.49), whereas for total[Hb+Mb] this was true only for RF (r = 0.45). Baseline deoxy[Hb+Mb] and StO2 correlated with V步 O2peak only for RF (r = ˋ0.50 and 0.54). In addition, the deoxy[Hb+Mb] slopes were not affected by aerobic fitness. In conclusion, while the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) did not differ between fitness groups the capacity to deoxygenate [Hb+Mb] (index of maximal fractional O2 extraction) correlated significantly with V步 O2peak in both RF and VL muscles. However, only in the RF did total[Hb+Mb] (index of diffusive O2 potential) relate to fitness
%K Diffusive oxygen potential
%K fractional oxygen extraction
%K peak oxygen uptake
%K time坼resolved NIRS
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5260088/