The purpose of this study is to clarify the physical activities of the Tokyo Factory Association, 1931-1940, which was the biggest association at that time. The results of this study are as follows:1) From September 1931 through 1937, the Tokyo Factory Association encouraged factory physical education for the purposes of promoting labor-capital cooperation, improving industrial efficiency, and promoting laborers' health. The activities of the association until 1937 consisted of training of the factory physical education leaders, popularizing factory gymnastics and folk dances by publishing brochures such as 'Factory Physical Education', giving lessons in physical education, lecturing on physical education, holding the Factory Physical Education Day and athletic meetings, and so on. Though free gymnastics was encouraged by the authorities and the association, athletic sports, martial arts, archery, sumo, baseball, and tennis were also activities practiced in those days. 2) From 1938 the activities began to change. In 1938 baseball matches and tennis tournaments that had been popular with laborers were suppressed. In 1940 the purpose of the factory physical education had a stronger nationalistic tendency of the day. Therefore, at the athletic meetings held in the same year, mass free gymnastics were encouraged and military sports were adopted.
For the purpose of studying evaluation methods of shock absorption and stability of gymnastics landing mats, we did experiments of jumps and landings in men's gymnastic vault with five toy-level male gymnasts. The landing performances and landing loads on four common skills were examined by 3-D high-speed video analysis and measurement of landing load with force plate. Consequently, we clarified the ranges of and the correlations between the parameters, namely, velocity and angle of the center of gravity, angular velocity of spin and twist, and maximum vertical and, horizontal load, etc. in the landing. The results were as follows: 1) The verticla velocity of the center of gravity on landing averaged from -5.2 to -6.0m/s in each vaulting skill. The horizontal velocity (longitudinal direction) averaged from 3.4 to 3.9m/s. 2) The angular velocity of spin on landing averaged 310, 620, 550, 500deg/s in 'Handspring forward and salto forward tucked', 'Cuervo stretched', 'Kasamatsu stretched' and 'Kasamatsu stretched with 1 / 1 twist', respectively. The angular velocity of twist averaged 20, 90, 215, 265deg/s. 3) The landing angles were different according to the landing direction. Namely, the landing angle of' Cuervo stretched', 'Kasamatsu stretched' and 'Kasamatsu stretched with 1 / 1 twist' averaged from 50 to 55 deg, and that of' Handspring forward and salto forward tucked' averaged 70 deg. 4) The extents of maximum vertical load, in the four skills ranged from 5.0kN to 9.5kN and their weight-ratios ranged from 8 r to 15. The maximum horizontal load extents ranged from 0.8kN to 3.8kN and their weight-ratios ranged from 1.5 to 6.5.
To discuss the dynamics of a snowboard turn, it is necessary to consider a) a snowboarder's snowboard control, b) the shape and mechanical properties of the snowboard, c) the contact mechanism between snowboard and slope, and d) the shape and mechanical properties of the slope. However, until the present, there have been no reports taking these factors into consideration due to the mathematical difficulty. Especially, it is difficult to explain the contact mechanism between snowboard and slope. The present study attempts to estimate experimentally the contact area between snowboard and slope. First, some models of snowboard are machined precisely by using machining center. Second, the contact area between the snowboard and slope is measured by using a thin sensor sheet. The effects of the slope (mechanical property and inclination), the snowboarder (weight and snowboard control), and the snowboard (width and length) on the contact area are discussed. From the experimental results and discussions it is concluded that one can estimate experimentally the contact area.
This paper deals with the measuring method of load distribution and the contact line between the ski edge and the snow. On the basis of many sensory tests, it is pointed out that the two factors of load distribution and contact line definitely affect the turning in skiing. In order to measure these factors in a room, we tried to make the testing equipment. The equipment was constructed from 20 load detectors installed longitudinally and the support rotated as an edging simulation. Testing materials were wooden GFRP-skis of 2, 000mm in constant length and variable side-cut and thickness. The following was clarified after the investigation of two factors by using the equipment. The load distribution is dependent on the thickness and is concentrated at the mounting area by load increase on ski plate. The contact line is dependent on the side-cut and the edging degree, regardless of the thickenss and the load which acts on the ski plate. From the results of testing these ski plates, it can be considered that this equipment becomes a very useful method for assisting in the design of Carving Ski and the evaluation of ski plate.
The effects of the inertia property of a club head to the restitution property of golf balls were investigated. The three-dimensional inertia properties of a golf club head were expressed by using the inertia ellipsoid. The inertia ellipsoid was cut in the plane which was parallel to the club face and passed through the center of gravity. The correlation between the cut ellipsoid and the restitution property was shown. It became possible by using the cut ellipsoid to express the restitution property on the golf club face. The restitution property was predicted by using the collision model of the rigid bodies. Furthermore, it became possible to prescribe the area of the high restitution on the golf club face from the inertia property of golf club head, its mass and the mass of the golf ball. With the technique used in this research, it is possible to predict the direction in which a high restitution area spreads out in the restitution property specially at the design. And a high restitution area can be predicted on the basis of three measurements of the inertia moment. Furthermore, rigid body collision simulation Twas examined. The simulation is consistent with the result of the experiment. By using this simulation it is possible to do more suitable design of the golf club head.