The subjects of this study are children belonging to a junior soccer club team which specializes in a single sporting event. We prepared an environment where G-balls could be used freely for a certain period and offered the subjects sporting programs. Our aim was to get fundamental knowledge on playing with G-balls through investigation of the inner reflection of the children and interviews with instructors. The result of the inner reflection investigation was as follows. The pleasantness was satisfactory with the score 4.8 out of 5 full points, in the first and the third trials in every class of the subjects. A tendency was observed through interview results with the instructors that the children in the class of elementary school enjoyed themselves by themselves at their free time, and students in the class of junior high school and high school utilized them for the purpose of training their body trunk or weight training. Furthermore, a tendency was also observed that the instructors comprehended the fundamental movement with G-balls as useful in the sense of body control.

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The purpose of this study was to obtain basic knowledge which was necessary for the coaching on the exercise using a Large-sized ball through the following two tasks.
1) The deformation of each a Large-sized ball was measured and compared when an adult man performed static and dynamic exercise tasks on 7 kinds of a Large-sized balls.
2) By using the characteristic a Large-sized balls that exhibited the largest and the smallest deformation, 10 adults performed the same exercise tasks on them; their inner reflection was compared.
The result of the investigation was as follows.
The deformation rate of each a Large-sized ball when static-weight exercise tasks were performed on it was different according to its kind. The smallest deformation rate was 10.5% and the largest deformation rate was 23.5%. In the case of the a Large-sized ball that exhibited the largest deformation rate, the part which touched the body of the performer sank and the position of the center of gravity of the performer was low, which tended to make it easier to perform the task.
On the other hand, the deformation rate of each a Large-sized ball when dynamic-weight exercise tasks were performed on it was also different according to its kind. The smallest deformation rate was 16.4% and the largest deformation rate was 28.8%.
70% of the subjects (7 persons) replied that they could perform the tasks "comfortably" on the a Large-sized ball which exhibited the smallest deformation rate, which showed the tendency that the material characteristics of elasticity of the ball could be utilized preferably.

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　We hosted events where light exercise was infrequently implemented, once every 2 weeks, for 4 months. The events were held as a class for group exercise "Session 25 in new sports college" aiming at middle aged and elderly persons with a wide spectrum in age and body strength, in which participants without much body strength could safely join because only a low burden was required in the activity. We measured and investigated the body strength and ADL before and after the events for the subjects comprised of 56 persons (men 9 and women 47). According to the results, we grouped the subjects into 3 cohorts in accordance with age, and 3 cohorts in accordance with the body strength at the time of starting, and compared the results for each cohort. At the completion time, for women, the cohort with higher age tended to be lower in grip strength, one-leg standing time with eyes open, and gripping bar reaction time (p<0.05, p<0.001, p<0.01). 　The grip strength for women was found to decrease as a whole irrespective of the results at the starting time (p<0.05, p<0.001), but as for the anteflexion in the legs-straightened seating posture, one-leg standing time with eyes open, and gripping bar reaction time, the cohort which was lower in body strength at the starting time tended to increase in ability, whereas the cohort which was higher in body strength at the starting time tended to decrease in ability. As for ADL, in women, the cohort with higher age tended to be lower in ADL, and both in men and women, the cohort which was higher in one-leg standing time with eyes open tended to be significantly higher in ADL (p<0.05, p<0.01, p<0.001).

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