The purposes of this study were firstly to observe relationship between positions of lower abdominal region (called “Seika-Tanden” in Japanese) and whole-body centers of gravity (CGs) in four types of the correct sitting posture (called “Seiza” in Japanese) and the sitting postures crossing legs on four conditions (called “Kekkahuza” in Japanese), and secondly to compare these postures by degree of spinal curvature which had measured with a conformateur. Four types of “Seiza” was prescribed as follows: (1) Tanza: incorrected “Seiza” , (2) Sokushinza: “Seiza” corrected with piling a top side in one foot on an arch of another foot, (3) Koushiza: “Seiza” corrected with crossing hallux, (4) Heishiza: “Seiza” corrected with placing toes side by side. Four conditions on “Kekkahuza” were (1) non-cushion, (2) one cushion, (3)add one more cushion, (4) add two more cushions. Estimation of CGs was based on H. Matsui's body segment parameters by means of pictures in profile. Positions of “Tanden” were obtained by T. Sato's drawing figure method. The subjects were eleven Judoist (on “Tanza” , “Sokushinza”,“Koushiza” and “Heishiza”) and a practician of “Zazen” (on “Kekkahuza”). The results were as follows:
1) As to characteristics in each posture estimated by degree of spinal curvature,“Tanza” characterized by a shape of that like an alphabet C, and the lumbar curvature was not found. On the other hand, the corrected “Seiza” (“Sokushinza”,“Koushiza” and “Heishiza”) and “Kekkahuza” expressed curvatures like an alphabet S that showed the same characeristics as a standing posture.
2) In both “Seiza” and “Kekkahuza”, the positions of CGs located above the navels, and the heights of CGs were higher than those of “Tanden”.
3) In“Seiza”, the antero-posterior positions of CGs were more behind than those of “Tanden”(50%).
4) About “Kekkahuza”, the antero-posterior positions of the CGs were in the rear of those of “Tanden” on all conditions (39.5-42.2%).

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For the purpose of determining the technical characteristics of the Kendo strike with the Jodan-no-Kamae in Kendo, we measured the impact force of the one-hand Shomen-and Kote-uchi using as subjects five college Kendo club students. And analyzed the data by a motion analysis system with a video tape recorder. We also measured the impact force of the two-hand Chudan-no-Kamae strike for comparison. The following are the results obtained from a biomechanical examination of the data.
1. The downward maximum magnitude of the impact force of the one-hand Kote-Uchi (150.03 ± 21.35kgf) was greater than that of the one-hand Shomen-Uchi (120.99 ± 11.55kgf). This difference was a characteristic of the one-hand strike but not of the two-hand strike.
2. The angular motion at the left shoulder, from which the Shinai is brought down, was greater for the one-hand Kote-Uchi than for the one-hand Men-Uchi. This will explain why the vertical component force of the one-hand Kote-Uchi was greater than that of the one-hand Men-Uchi.
3. With respect to the vertical movement of the Kensen, the maximum speed was greater for the one-hand Kote-Uchi than for the one-hand Men-Uchi while the opposite was the case with respect to the forward movement. This was in accord with the observation that the maximum magnitude of the impact force was greater for the one-hand Kote-Uchi than for the one-hand Men-Uchi with respect to the vertical movement whereas the opposite was the case with respect to the forward movement.
4. The correlation coefficient between the impact time and the maximum magnitude of the impact force was small whereas the correlation coefficient between the impact time and the impulse value was great.
5. There was not an appreciable difference in the magnitude of the impact force between the one-hand and two-hand Men-Uchi. However, with respect to the right Kote-Uchi, the maximum magnitude of the impact force was greater in every direction for the one-hand strike than for the two-hand strike. Most notably, with respect to the downward movement, the maximum magnitude of the impact force of the one-hand Kote-Uchi was greater than that of the two-hand Men-Uchi.

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The purpose of this study was to investigate the influence of Judo practice on cardiorespiratory and blood properties in summer season which is relatively a hot environment. Subject was 4 young male Judo players. Average of VO₂max among 4 subjects was 4.071/min,53.6ml/kg/min. Average value of heart rate during practice was from 154 to 178 beats/min. Predicted oxygen uptake during practice of Kakari-Renshu, Randori, additional practice for Newaza and Newaza was represented percentage of VO₂max,82.9%,85.0%,80.4%, and 82.9%, respectively. But it is difficult to investigate the work intensity because of exercise mode of Judo was included factor of intermittent exercise, indeed it was considerable possibility that intensity was the lower than result of this study. As a result of blood properties, although we observed weight loss with much use of skeletal muscle for practice of Judo, we didn't find the influence of Judo practice on cardiorespratory and blood properties in summer season.

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Isokinetic muscle strengths of kendo players were observed at fifteen male kendo players. The subjects were grouped into higher competitive ability (H-Group; 7 persons) and non-higher competitive ability players (NH-Group; 8 persons). Isokinetic muscle strengths at various speed were measured at elbow, trunk and knee by Isokinetic dynamometers. The results were as follows: 1) There were not significant differences in physique and body composition between two groups.2) Elbow extension force (absolute value) of H-group was significantly larger than NH-group.3) There were not significant differences in knee extension and flexion forces between two groups.4) Trunk extension force (back strength) of H-group was larger than NH-group.5) Circumferences of right upper arm, forearm and thigh were significantly larger than that of left ones, but the value of left calf was significantly larger than that of right one.6) Elbow extension force of right arm was significantly larger than that of left one, but for elbow flexion force the value of left arm was significatly larger than that of right one.

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