Baseball is one of the most popular sports in Japan and in U.S.A. However, many players, especially pitchers, have shoulder injuries incurred during pitching motions because the shoulder suffers repeated stress in the late cocking phase. In that phase the shoulder is externally rotated far beyond the normal range of motion by the inertial force applied on the forearm due to the rapid forward movement of the shoulder. Many researchers have analyzed pitching motion. However no one could calculate the inter-joint force applied between the glenoid fossa and the humeral bone. They calculated the "joint force", which makes the center of gravity of the upper arm accelerate or decelerate. This force is different from inter-joint force. The purpose of this study was to calculate the joint moment, the muscle force, and the inter-joint force on the shoulder during pitching. The subjects were five elite baseball pitchers. Twenty-five reflective markers were attached to the subjects. Four 60-Hz CCD TV cameras (Expert Vision; Motion Analysis) were used to calculate 3D locations of these markers. Shoulder joint angles were calculated from the orientation of the markers. Eulerian angles were calculated to represent the spatial orientation of the upper arm and the fore arm. Angular velocity around the local axes fixed on the upper arm and the fore arm were calculated from Eulerian angles. Joint moments were calculated from the angular velocity and angular acceleration. As the first step of this study, joint moment and joint force, which were calculated by the ordinal method, were analyzed. The ball speeds of these trials were 71 to 87% of each subject's average speed during real baseball matches, so the trials were suitable for analyzed. The average time of the late cocking period and acceleration period were 73ms and 54ms respectively. These were comparable to the 60ms and 50ms of Pappas's results. Maximum external rotation of the shoulder was about 55 degrees, which was smaller than Feltner's data. The angular velocity, joint force, and joint moment were smaller than the Feltner's results. The reason why our results were smaller than others' was partly due to the difference in physical stature between Japanese and American players. Maximum external and horizontal adduction moments were found in the late cocking phase, not in the acceleration phase. All joint moments decreased when the ball was released. Approximately 54ms prior to the ball release, the shoulder was rapidly rotated in the external direction, and it was believed to cause the over-stress on the shoulder joint. At the same time, however, the shoulder was horizontally adducted to reduce the stress.

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This paper reports on a virtual training environment developed using virtual reality technology with force and visual image feedback capability. In our system: (1) A light and safe force-display implemented using a pneumatic rubber actuator is available. It has a wide range of motion and large driving force comparable to those of human joints and muscle. (2) The trainee's muscle characteristics can be measured. (3) The parameters of the training environment (e. g. spring constant, weight of dumbbell) can be changed easily so as to obtain an environment best fitting the characteristics of human muscle. In order to accomplish the above purposes, a system must be capable of freely generating and controlling the physical and psychological elements of a training environment. For the first step, applying virtual reality techniques, we are developing a computer controlled training system which can generate and control various audio/visual images and forces to be applied to the trainee. Currently, however, we have decided to limit the scope of implementation to the upper extremity as the training target, and to visual images for the environmental information. The trainee using this system wears a force-display which can apply force to his/her upper extremity and a head mount display through which he/she can see the virtual world, a room with wall, windows, etc., in which a spring and a dumbbell are placed in the room. The trainee can "use" these sporting goods and can feel forces on his/her upper extremity as if he/she were actually exercising using them. By measuring the trainee's muscle characteristics and setting them in the system's computer before starting a training session, an improved training environment results. In addition, in the case of rehabilitation, the system can provide information such as video images of rehabilitation history data, which can help increase the trainee's motivation for attending the exercise. In our system, an important role is played by the actuators which are attached to the force-display to generate various reaction forces. An actuator serving those purposes should be safe, small, light, and capable of high force output. As human muscle of the upper extremity is much stronger than the muscle of the fingers, an actuator with high output is very desirable. It is also important that the apparatus not feel unpleasant to the trainee when he/she wears the force-display. For these reasons, we have chosen a pneumatically controlled rubber actuator.

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To investigate the influence of alpine ski event results on the new devised performance test for alpine ski racers (call for Bosco test). Bosco test evaluates the performance in the jumping height that carries a barbell on its shoulder with weight load from 0kg to 50kg at random, and indicate counter, and it is consisted of from vertical posture to squat posture with countermovement, and jump performance, and evaluation whether performance in the jump height; experimentally. The subjects were ten male alpine ski racers. Five kind of extra load on the counter movement of jump exercise test. The analyzed mechanical parameters are on the basis of flight time (sec), peak velocity (m/sec), peak force (N), and peak power (watt). As a result of having compared it in relationship with event results, by an International Ski Federation (F.I.S. 2008 version) of point , It was recognized significantly correlated (r= -0.64~-0.75 p<0.05) between in slalom point and jump height by Bosco test and out put mechanical power. It was observed that the alpine ski giant slalom point was significantly correlated to these variable in Bosco test condition and also to jumping height of center of gravity (p<0.05) and peak power (p<0.05) in Bosco test. In conclusions , Bosco test result have suggested in that it was an effective evaluation of physical fitness index was shown as a measurement and evaluation physical fitness characteristics as ski performance event results of an Alpine ski athlete.

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全日本スキー選手権大会に出場した33選手の実際の競技場面でのスキージャンプのサッツ動作についてAPASのコンピューターで3次元動作分析を行った.33選手を純ジャンプ群, 複合ジャンプ群, ジュニア群の3群に分けて, それぞれの下肢3関節の角速度, 踏切時の助走速度を検討した.純ジャンプ群はLarge hill, 複合ジャンプ群およびジュニア群はNormal hillでのジャンプであった.1.純ジャンプ群と複合ジャンプ群にだけ股関節と膝関節の角速度のピークは同期していた.また, 足関節の底背屈はわずかに行われていた.2.純ジャンプ群の股関節の角速度ピーク値は809～1227, 平均968.9deg/s, 純ジャンプ群の膝関節の角速度ピーク値は620～1124, 平均875.8deg/sに対して, 複合ジャンプ群の股関節のそれは, 439～565, 平均508.6deg/s, 膝関節のそれは469～670, 平均553.5deg/sであった.3.ジュニア群の股関節, 膝関節のカーブは, 種々なカーブを示した.そのピーク値は股関節が269～617, 平均463.6deg/s, 膝関節が320～696, 平均463.5deg/sであった.4.ナショナルチームのほとんどの選手はサッツ動作の際に, 足関節の角速度の最大値にしても, 300deg/s以下であり, ジュニア群の半数以上の選手が300deg/s以上であった.5.純ジャンプ群の助走速度は2312～2372, 平均2333.9cm/sで, take-offの0.1秒前よりサッツ動作を開始する.複合ジャンプ群のそれは2319～2358, 平均2333.3cm/sで, take-offの0.1秒前よりサッツ動作を開始する.ジュニア群のそれは1868～2322, 平均2112.7cm/sで, take-off0.1～0.2秒前よりサッツ動作を開始し, ばらつきが目立った, 以上より, サッツ動作は1.股, 膝関節の角速度のピークは同期していた.2.統計学的に股, 膝関節の角速度は高いほど, 飛距離を長くしていることがわかった.3.足関節はカンテを蹴るのではなく, 押すのである.4.各ジャンプ群の足関節速度に有意差はなかった.5.統計学的に助走速度が速いほど飛距離を長くしていることがわかった.垂直抗力や空気抵抗に負けないで, サッツ動作を起こすためには腰背部, 殿部や下肢の筋力も重要である.

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This study focuses on the introduction of aerobic dance in Japan in the beginning of the 1980s.It examines the image aerobic dance was given and how it was introduced. The results are as follows:

(1)Ken Cooper’s book, Aerobics, was published in 1968. In it, Cooper defined “aerobics” as a variety of exercises, such as running, swimming and walking. The Cooper’s aerobics theory was introduced to Japan in the 1970s.

(2)Jackie Sorensen devised “Aerobic Dancing” as the first aerobic dance program based on Cooper’s aerobics theory and opened a Japanese branch office in 1980. Ken Cooper visited the Asahi Aerobics Seminar held in 1981 where his theories were used to present aerobic dance as a form of physical fitness.

(3)In 1982 The Sports Collection opened in Japan as an exercise club using aerobic dance from America. In the same year the advertising agency Daiiti Kikaku also presented aerobic dance to the Japanese public with the sponsor, Otukaseiyaku, broadcasting the television program “Aerobicise” and drawing from the Oronamin C Aerobics Campaign. Both of these were connected with a concept that explained aerobic dance as a form of entertainment or topical gimmick, and not an actual fitness program. These two experiments identified aerobic dance with an image of being a violent dance performed by women in high-cut leotards.

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