Association between muscle aerobic capacity and whole-body peak oxygen uptake.

Abstract

Decline in skeletal muscle mitochondrial oxidative capacity (MOC) is associated with reduced aerobic capacity and increased risk ofcardiovascular and metabolicdisease. Measuring skeletal muscle MOC may be an alternative method to assess aerobic capacity, especiallyfor individuals unable to perform a whole-body maximum oxygen uptake protocol. In this study, linear regression analysis in two leg muscles was performed to determine whether MOC values could be used to predict whole-body peak oxygen uptake. MOC was measured with near infrared spectroscopy (NIRS) inthemedial gastrocnemius (MG) and vastus lateralis (VL) musclesof 26 participants (age, 27.1 ± 5.8years old). Whole-body peak oxygen uptake (VO2 peak) was determinedby indirect calorimetry during a continuous ramp protocol on a cycle ergometer. VO2 peak values were significantly correlated with the muscle recovery rate constant (k)ofthe MG (kMG,r = 0.59;p < 0.01) and VL (kVL,r = 0.63; p < 0.01) muscles. Summingrecovery rate constantsof both muscles together (kMG + kVL)improved thestrength of thecorrelation with VO2 peak (r = 0.78;p < 0.0001)andcouldexplain amajorityof the variance(R2 = 0.61)between the two measurements. Data suggest that NIRS can provide reliable MOC measurements on two leg muscles that correlate well with whole-body peak oxygen uptake.