In the metabolism of exercising muscle, to understand the form of the demand and supply of oxygen, to fine out the suiTable exercise intensity and the effective exercise form for the health through the exercise evaluation, the 17 subject of the age 17 to 21, in the D-University were selected. Appril 7. 1997 to Jun 28. 1997, we prescribed the subjects the running group(8 subjects) and the swimming group(9 subjects) carried into effect most generally. During 12 weeks, they performed aerobic training, and then, when they performed the graded maximal exercise test using the bicycle ergometer, we observed the oxygenation(%) and blood volume(O.D) in the NIRcws. As the results, the observed value showed the regarded increase after the training in the basic research, VO_2max(㎖/kg/min), HRmax(bests/min), VEmax(ℓ/min) and exercise duration. The next, according to the change of the muscle oxygenation and blood volume indecating the form of the demand and supply of oxygen in the exercising muscle after the training the result was summarized the following three point. 1) When they started the exercise, in both groups, consideration was given to the supply of oxygen before the consume. This result accordingly, the result show the necessity of the warming up to protect the injury during the exercise. 2) First, when we observed the form of oxygen consume in the ventilatory threshold(VT), the oxygen consume increased much more in the running group. Nextly, the form of oxygen supply was similar to the state before the training in both groups. 3) In case of the high intensity exercise, the oxygen consume regarded increased in swimming group, the supply decreased remarkably in both groups. It seems that this phenomenon was the result that the increase of O_2 extraction in the exercising muscle was more then the trend by the increase of arterial blood flow and venous return. Also, because of the improvement in the contractile force of the exercising muscle and the rise in bodily temperature by the increase of exercise duration, there was a decline in blood volume. In view of the results, in the low intensity exercise the consume and supply of oxygen was affected more by the increase of arterial blood flow and venous return than the increase of the O_2 extraction, but in the high intensity exercise, strongly by the increase of the O_2 extraction in the exercising muscle. Therefore, the proper intensity of exercise to keep and improve the health was the maximum intensity of exercise within the range aerobic exercise of performing the aerobic exercise in the exercising muscle and then, it is more useful that the running exercise is performed at the exercise intensity under the VT and the swimming exercise is performed at the highest exercise intensity. In this study, because of the difficult of the method of measurement, there are many unclear point. However, it is very significant that the non invasive and continuous measurement by NIRcws is made possible. It may be say in this connection that, because this study evaluated the relative value, more study is required. Key words : exercising muscle, NIRcws, blood volume, O_2 extraction, ventilatory threshold(VT)