Kinesiology is inviting keen interests among the physical educators in Japan. For example, twelve young kinesiologists presented their results in various international conferences in these three years. Considering the fact that there were fourteen presentations of such nature ever made in its young history by the Japanese researchers, the trend is more than significant in that the futue of research activities in kinesiology is quite promissed. It should be remembered, however, that noticeable number of books in the said field had been published since 1920. It was 1957 when the Division of Studies in Kinesiolology was first established in the Japanese Society of Physical Education. The number of research results presented in the annual convention since amounts to 682, while 83 studies have have published in the current journal. The development of studies in kinesiology as traced by these research reports may be analyzed as the followings : During the early years, attention was given on the figure and figure controling, and on various body movements by analyzing loci of body parts using pictures and motion films. Later, measurement of physical parameters on the body movements applying electronlc devices has been attempted, and thus, force, velocity and power in relatlon to body movement have been investigated. In the recent years, exertion, transfer and action analysis of strength, by means of electromyography, along with development of EMG integrator, has accelerated the research activities. The scope of research has been widened now, due to application of telemeter apparatus. The epoch making event in the research trend of kinesiology was the First National Kinesiology Seminar, held in July, 1972, in Nagoya City, to which l00 researchers attended under the title of "Kinesiological studies of human power." With the zest and energy of the participants, instructional and discussion sessions took place, about various devices of kinesiological studies, including EMG, computer system, photography and electronic apparatuses. The seminar was a great success indicating the growth of the group of people as well as the promissing future of kinesiology in Japan.
It has been observed that the tonic discharge disappears for some extent immediately preceding the act in rapid voluntary movements. To reveal the mechanism of this phenomenon, a series of experiment was conducted in healthy normal subjects. The action potentials were led-off by bipolar surface electrode, simultaneous mechanical response was recorded with resistance strain gauge transducer. While a subject made a slight voluntary contractions and maitained it steadily, he was asked to respond with a rapid voluntary movements as quick as possible to a visual or acoustic stimulus. The latency of this silent period in elbow extension was found to be around 40 msec at minimum. It was also found that the most consistent results were obtained by using upward jumping movement. The silent period preceding the act usually occurred in the musle synergist; however, antagonist showed the same silent period simultaneously. This finding suggested this phenomenon was not to be reciprocally innervated. The silent period in the triceps brachii and the rectus femoris were simultaneously found in the electromyogram of the whole body movements such as the starting in sprint running. It was supposed from these results that the center in the brain or brain stem sent some inhibitory discharge to the motoneurons in the ventral horn of the spinal cord.
The purpose of the present study is to investigate the effect of physical exercise on the performance of calculation. As a resu1t of pedaling on the Monark's bicycle ergometer with loads gradually increased to the point of exhaustion, the performance of simple calculation (addition) obviously increased. At the same time, the finger volume measured by means of the water plethysmograph reduced more clearly after physical exercise. The heart rate, the respiration rate and the blood pressure during calculation rose prominetly. After exercise, these factors were accelerated by calculation moreover. It can be considered that the mechanism of improvement of the calculation performance caused by physical exercise should be closely related both to the advanced wakefulness and to the reinforcement of the orienting reflexes.
The atrophy of muscle fibers after the cutting of N. fibularis profundus to M. tibialis ant. was studied histologically by making a distinction among red muscle fibers, medium muscle fibers and white muscle fibers. The experimental animals, Wistar-strain rats, were devided into two groups, namely the nerve-cutting group and the control group. In the nerve-cutting group, N. fibularis profundus was cut on the 70 days after birth. M. tibialis ant. was removed on the 10 days and 20 days after the cutting of nerve. The histological method, using Sudan black B stain, was adopted. The results obtained were as follows : 1) No apparent effect of the nerve cutting on the rats' body weight could be observed. 2) The decreasing rate of the weight of M. tibialis ant. was 28.4% on the 10 days and 39.8% on the 20 days after the nerve cutting. 3) In the group of the 10 days after the nerve cutting, the decreasing rate of the entire area of cross section at the middle part of M. tibialis ant. was 19.3% in red muscle fibers, 34.7% in medium muscle fibers, and 43.7% in white muscle fibers. 4) The effect of the nerve cutting on the average area of cross section per fiber showed the same tendency as that on the entire area of cross section in red muscle fibers, medium muscle fibers and white muscle fibers.