Eight healthy college students volunteered as subject to determine the submaximal exercise intensities based on the arterial blood lactate concentrations during the incremental exercise test.
　The incremental exercise test consisted of 4-min unloaded pedalling (Monark ergometer), and thereafter 25 W increased every minute until volitional exhaustion. To obtain the change in blood lactate concentration, arterial blood was collected by inserting a catheter into either the radial or brachial artery with local anaesthesia. Then, the intensities of submaximal exercise tests were determined at the workload which the arterial lactate began to increase above the resting value (AT level), at the workload corresponding to the value of 2 mM arterial lactate (2 mM LA level), and at the workload corresponding to 4 mM LA (4 mM LA level). The submaximal exercise tests were performed at these intensities for 15 minutes. Oxygen uptake was measured by the Douglas bag method and arterial lactate was determined by the enzymatic method.
　During the submaximal exercise tests of the AT level, VO₂, % VO₂max, heart rate and LA were well coincided with the predetermined value at the incremental exercise test. However, at the 2 mM LA level and 4 mM LA level, the parameters obtained during the submaximat exercise test tended to overestimate the predetermined value, respectively.
　These results indicate that the intensities based on arterial blood lactate were one of the most usefulness for training or rehabitation activity, but that further investigation would necessitate for this method to be most commonly used.

DESCENTE SPORTS SCIENCE Vol.24/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE