The purpose of this study was to measure the degree of stability of Various standing postures when external force was applied to the body. The subjects (16 healthy adults) were asked to resist against an external force with a maximum effort in nine different defensive postures. These postures were divided into two groups: one in which the hip or knee joints or both were flexed and the other with the feet spread apart in different positions. A rope was wound to the chest of the standing subject. The other end of the rope was attached to a winch which was rotated electrically at the desired speed. The rope was pulled at speeds of 10.6, 32.3, 53.7, 76.8 and 105.4cm/sec, respectively. The rope was pulled continuously at a uniform rate until the subject could not maintain his initial position. The tensile force of the rope was measured with a semiconductive strainmeter. The maximum tensile force of the rope represents the maximum resistant force exertet by the subject against the external force. Quadratic equations between the maximum resistant force and the pulling speed were determined by the least squares method in the rigid body. Y = a_0 + a_1V + a_2V^2 (Y : the maximum resistant force; kg., V: the pulling speed; cm/sec) (0 < V < 105.4). The same relationship was found in an erect posture with a closed stride position for each subject. Although a relationship was found in the other postures in which the higher the pulling speed, the greater the resistant force, the quadratic equations could not be obtained. The most stable posture was a crouching one with one foot in front of the other and the least stable posture was an erect one with a closed stride position at all speed. For the most stable posture, (make the resistant force greatest) the position with the knee and hip joints flexed was more effective than that with the feet spread. As a conclusion, the muscular activity has a large influence on the stability in the human standing posture in addition to the mechanical principles.

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The purpose of this study was to obtain materials and data of the anticipative function of forearm upon the motor external disturbance. Subjects are requested to pursue one beam in the CRO or to hold one beam in the same position and are forced to move or td keep their forearm still for the anteroposterior direction horizontally. Suddenly in this movement, many kinds of external disturbances were added to the motor system of Subjects. Responses against disturbances were utilized as the data of anticipative function and fundamental characteristics of this function were analyzed according to the automatic control theory. Furthermore, two kinds of motor disturbances which were brought about two anticipative function of dynamic and static nature are discussed and analyzed. The results were as follows: 1. Quickness and performance in the anticipative function were remarkably elevated at the midway of movement courses, when the regular interval disturbance was added to static holding. But irregular interval disturbances did not have the effect of the improvement in this function. 2. In the dynamic frequency tracking, the anticipative performance showed the most optimal record at the rectangular wave of 0.4Hz. 3. Comparing two movements pattern of forearm, such as the elbow extension and flexion, the anticipative quickness of the latter clearly displayed more speedy result than that of the former. 4. When the anticipative function existed in the tracking response, integrated EMG of the flexor muscles had larger voltage than that of the extensor.

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This study was attempted to investigate the characteristics of fundamental motor ability and its degree of contribution to motor performance in various sport activities. The sixteen test items, which were picked out of the areas of physique, physical function and motor ability, were administered to 394 athletes (selected out of 9 sport teams) and 50 non-athletes of 10 senior high schools. Principal factor analysis was applied to the correlation matrix of each team which was calculated with these variables, respectively. Thus, the first principal factor was interpreted as a fundamental motor ability factor, because this factor correlated with most of variables at high significant level and in addition, had the largest amount of contribution to total variance. Thus, the characteristics of fundamental motor ability, the degree of contribution of fundamental motor ability factor to total variance and the degree of contribution of subsets of variables to the variance of fundamental motor ability factor were investigated in each sport team, respectively. The results were summarized as follows: 1. Track and field and basketball teams were superior in fundamental motor ability, while tennis and non-athletes were poor. 2. As for the degree of contribution of fundamental motor ability to motor performance in sport activities, baseball team showed the largest value, and non-athletes, tennis and soccer, the next largest values, while basketball team showed the smallest value, and track and field, gymnastics and judo, the next smallest values. Consequently, it is considered that the teams, whose fundamental motor ability factor showed the large contribution to motor performance, are needed to have more fundamental motor ability in performing their own sports than the other teams whose contributions were not so large. 3. As for the degree of contribution of the subsets of variables to the variance of fundamental motor ability factor, physique variables were remarkably larger than the other variables in all teams except gymnastics and judo teams. In addition, as to the other elements but physique element, the explosive strength of lower and upper limbs and static muscular strength were somewhat larger. But if another investigation would be made by removing the influence of physique variables, a certain difference will be resulted in.

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The purpose of this study is to investigate the energy expenditure of the students during school hours of physical education in junior high school. From a course of study which was set by the Ministry of Education, truck and field, gymnastics and volleyball activities were taken up for measurment of energy expenditure. The activity time of each student in school hour was analyzed in seconds by the time study methods using tape-recorder and video-tape-recorder. The subjects were 117 healthy junior high school boys. The results were as follows; (1) In a course consisted of sprint and running broad jump, the mean R.M.R., Exercise Quantity Index (EQI) and Calorie Expenditure (CE) during 50 minutes were 2.19, 109.5, and 149.8 Kcal, respectively. The mean R.M.R., EQI and CE were 2.50, 125.0, 168.6 Kcal in the sprint event, 2.94, 148.6, 185.5 Kcal in the running broad jump event, 2.27,132.3, 158.1 Kcal in the vaulting box course, 2.35, 117.3, 166.2 Kcal in the volleyball event, respectively. (2) The R.M.R. of various activities obtained materials were as follows; 65.1 for 50m dash, 43.5 for running broad jump, 19.6 for vaulting box, 55.1 for spike action in volleyball, 41.9 for blocking in volleyball and 33.6 for volleyball rolling receive. (3) For each student, the actual exercise time length for given teaching material was rather short in one school hour of physical education. For example, the ratio of actual exercise time to one school hour was 7.4% in the sprint material, 8.2% in combination of sprint and running broad jump, 7.4% in the running broad jump, 10.5% in the vaulting box and 6.7% for the volleyball, respectively. In many cases, mote than 50% of one school hour was found to be occupied by sedentary activities. (4) The margin of error between the value of time study method and the observed value was not more than 1O%. (5) The results of this investigation show that the mean exercise intensity and actual exercise time with respect to R.M.R. and EQI in one school hour are insufficient to improve the physical fitness of junior high school students. Accordingly, instructional technique, educational equipment and facilities should be reexamined from a stage of planning for school physical education.

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