[Determination of Aerobic-anaerobic Transition in Working Muscle Using EMG and Near Infrared-Spectroscopy Data].

A new method for assessing the aerobic–anaerobic transition (AAT) in energy supply of exercise of a small- and large-muscle mass by the dynamics of the integrated electromyographic (EMG) activity indicators and changes in the content of deoxygenated hemoglobin (HHb) in the muscle tissue is proposed. Subjects performed two incremental exercise tests until exhaustion: the bicycle ergometer test and one-legged knee extension test. The dependence describing the change in the HHb content in m. vastus lateralis and its EMG activity during the test has a characteristic maximum, which corresponds to the AAT. Significant correlation (r = 0.78; p < 0.05) between the power at AAT and the power at the anaerobic threshold determined by the lactate concentration in capillary blood was found. It was shown that this method for determination of AAT is also suitable for determining the aerobic–anaerobic transition during the exercise of small-muscle mass.