Specific Intensity of Physiological Costs during Cyclic Operation of Different Power

The aim of the study is the search for heart rate criteria of the rate of energy consumption during intense cyclic work. In the first part of the study, nine athletes (qualified athletes, age 18.3 ± 1.5 years, weight 72.2 ± 8.04 kg), specializing in BMX (Bicycle MotoX), performed on different days a series of five all-out exercises on a cycle ergometer at a maximal power output and fixed durations of 10, 30, 60, 120 and 360 s. In the second part of the study, eight road racers (qualified athletes, age 21.3 ± 3.4 years, weight 72.9 ± 11.3 kg) performed two exercises on the cycle ergometer at the aerobic threshold and at the anaerobic threshold, each trial lasting 30 min. We observed a high correlation (p < 0.05, R2 > 0.9) between the paired values of the specific intensity of physiological costs (SIPC), calculated from oxygen consumption ( SIPC_O₂ ) and heart rate sums (SIPCfh). This correlation was present throughout the whole range of exercise intensities—from the aerobic threshold to maximum anaerobic power. Thus, it is possible to use the SIPCfh parameter in training practice for assessing the rate of energy consumption during exercise.