Intraindividual variation in oxygen debt was determined following maximumeffort work and a near-maximum-effort work at a given rate by means of the Monark's bicycle ergometer for sixty seconds. Both experiments were carried out four times, respectively. At the same time the measurement of work done and rectal temperature at rest were taken. Every experiment was carried out once a day at the same hour (9 : 00) on the moring of Monday.
Intraindividual variation in oxygen debt, work done and rectal temperature was expressed in terms of a coefficient of variation (C. V.: %) . The subjects were four healthy male students, aged 18-21.
The results obtained are as follows
1) The C. V. value of intraindividual variation in oxygen debt following maximum-effort work was from 4.7% to 15.3% and its mean value was 9.1%.
2) The C. V, value of intraindividual variation of the work done following maximum-effort work was from 0.7% to 2.5% and its mean value was 1.4%.
3) The C. V. value of intraindividual variation in oxygen debt following a nearmaximum-effort work at a given rate was from 7.0% to 12.8% and its mean value was 9.5%.
4) The mean value of the work done following a near-maximum-effort work at a given rate was 85.8% in contradistinction to maximum effort work. The mean value of C.V, of work done was 1.1%.

We made the subjects take the exercise of six kinds from 5 to 90 seconds with maximum effort by Monark's bicycle ergometer. And we studied on anaerobic work by means of measuring the course of mechanical power, blood lactate, and oxygen debt.
The results were as follows :
1) The mechanical power reached the maximum value from about 3 to 6 seconds after beginning the exercise regardless of the subjects and the work times, and then it decreased gradually with the passing of time.
2) The subjects who sent out the higher power in each work time within 60 seconds indicated the higher blood lactate and oxygen debt.
3) The relation between the oxygen debt per lean body mass and the blood lactate was found to be linear when the oxygen debt was less than about 110 ml, in other words, within about 60 seconds in the work time. But this relation became lower when the oxygen debt became over about 110 ml, or, the work time passed more than about 60 seconds.
From these results we classified the work of maximum effort as follows:
(1) the anaerobic work within about 6 seconds, (2) the work which contained a great deal of anaerobic factor from about 6 to 60 seconds, and (3) the work in which aerobic factor began to increase when the work time passed about 60 seconds.

We measured the power that sprinters and non-athletes put out by Monark's bicycle ergometer under eight work loads from light to heavy.
Also we measured the power that was put out when sprinters and non-athletes repeated the work that recorded the maximum power respectively 10 and 9 times.
The results were as follows :
1) Large difference was not found between the largest power of sprinters and that of non-athletes in the works of 3 or 4 kp light work loads. But considerable difference between the largest power of sprinters and that of non-athletes was found as the work loads got on heavy from 5 to 7 kp. Sprinters who had best record of 10''7-10''9 in 100 meters dash put out the maximum power (90.4-105.8kgm/sec) under the work loads of 7 or 8 kp. On the other hand non-athletes put out the maximum power (62.1-85.2kgm/sec) under the work loads of 5 or 6 kp.
2) As the work loads got on heavy from 5 to 7 kp, such a large difference between sprinters and non-athletes was not found in forces, but remarkable difference was found in speed. And sprinters were better in speed under comparatively heavier work loads than non-athletes. This was a factor which caused the large difference in the max-imum power between sprinters and non-athletes.
3) The maximum powers which were put out by all subjects except two sprinters were situated on almost a straight line. But those of two sprinters were situated on the left of that line. This means that two sprinters excelled power output especially in speed.
4) When sprinters and non-athletes repeated the work which put out the maximum power respectively 10 and 9 times, having a rest for 4 minutes between the works, the powers did not indicate great decline from 1 to 910 times in both sprinters and non-athletes. But when they repeated the same work, having a rest for 1 mimute between the works, the powers indicated a considerable decline from about 5 to 910 times in both sprinters and non-athletes. And the rate of those decline did not indicate great difference between sprinters and non-athletes.
5) We found out three types on the power output in both sprinters and non-athletes as follows : (1) compared with the power decline from 4 to 5 sec, the rate of that from 5 to 6 sec was considerably high, (2) the power declined from 4 to 6 sec, and the rate of this decline was comparatively small, (3) the rate of power decline 4 to 6 sec was wholly maintained high.