Associations between heart rate threshold, lactate threshold and muscle tissue oxygen desaturation in competitive female cyclists

Research has identified the lactate threshold (LaT) as a measurement of exercise intensity. Muscle tissue oxygen saturation has been observed non-invasively by near infrared spectroscopy (NIBS). The purpose of this study is to examine associations between the heart rate threshold (HRT), LaT, and percent muscle tissue saturation (StO2) during exercise in eighteen elite female cyclists. Each performed a maximal cycle test to volitional fatigue. Venous blood lactate (mM), heart rate (bpm) and StO2 (%) were collected every minute. Thresholds were identified utilizing logarithmic transformations of data and the point disproportionate variable rate change. Correlation coefficients were determined to recognize associations between variables. Statistical significance was set at p ≤ 0.05. Significant associations were established between the collected variables. Thresholds for muscle tissue oxygen saturation, heart rate and lactate show associations in elite female cyclists. In addition, HRT is significantly associated with LaT. Non-invasive procedures for determination of LaT may be provided by StO2 and HRT.