The effect of isokinetic training was investigated for the strength development in the thigh muscles under various training conditions. Thirty one males from healthy high-school students served as subjects of this study. Training was performed using a Cybex II machine with two kinds of repeated load conditions (number of repetitions, cf. Table 1 & Fig. 1) at to different rotational speeds (30 degrees and 180 degrees per second) . The training was done three times per week for nine weeks. The effects of training were evaluated on the basis of the amount of increase in the strength during knee flexion and extension.
The results were summarized as follows :
1) The effect of training became apparent most swiftly under the rotational speed of 180 degrees per second and light load of repetitions, respectively.
2) The largest increase in the muscluar strength was observed for the group with training speed of 180 degrees per second and hevey load of repetitions, respectively.
3) The strength increased periodically every four or five week for all conditions.

1. We observed how brain waves change, especially in frequency, during the period of physical exercise training as subjects are becoming more skilful.
2. In the first, subjects, with eyes closed, were given bicycle ergometer load in the hypnotic state, the brain waves of the subjects were clearer when they were suggested that they can pedal easily than when they were suggested that their pedaling is heavy.
3. In the second experiment, we took up a fourteen-year-old school girl as a subject, who had been unable to ride a bicycle and whose brain wave shows no alpha blocking while her eyes are open. Using a radio-telemeter, we took her electroencephalograms every day for about ten days when she was learning bicycle-riding. As a result, we find that her brain waves were complicated at first when she was pedaling with voluntary effort and with others' help, and that they were becoming simpler as she got used to riding, until alpha waves began to appear with her skill in and smoothness of riding.
4. In the third experiment, with a number of novices in skiing as our subjects, we made electroencephalographical observations of them practising on natural snow. In order to avoid the alpha blocking, we imposed the condition that they keep their eyes closed during the experiments. Brain waves were taken by using a radio-telemeter, whose receiver was set in a house and antenna in the middle of an about seventy-meter slow descent course. Because of their closed eyes, they seemed to feel no little fear so that their brain waves were too complicated to analyze and were mixed with electromyographical fluctuations. But as they became more skilled, their brain waves were more normal and simpler, until even alpha waves sometimes appeared during smooth descent skiing.
5. When we learn new exercise, we need higher mental activity using the cerebral cortex in the beginning, but that as we are growing more skilled and more used to the exercise, our mental activity becomes a lower and reflexive one that needs no much participation of the cerebral cortex. And alpha wave become to appear in the brain waves.
6. We discussed that how related our researches are with Jasper and Penfield's beta wave and “rhythme en arceau” of Gastaut and Chatrian in rolandic region blocking owing to the voluntary movement. It may be given a conclusion that electroencephalographic blockings are based on the mental activity of the preparation to voluntary movements.