When considering the preventive effect of sport on osteoporosis, it is important to determine whether a sport leads to elevation of peak bone mass. Our studies demonstrated that not only baseball players who practiced for an average of 36 hours or more per week but members of basketball clubs at universities practicing an average of approximately 9 hours per week could be expected to acquire significantly higher BMD. In females, due to marked reduction in bone mass after menopause, it is important to determine whether a sport in middle age can prevent bone mass decrease and if so, what degree of impact is needed. Our studies proved that even if females continued in a sport from youth and had a high level of bone mass before menopause, habitual exercise from regular volleyball practice for about 5 hours per week was far from being sufficient to maintain bone mass after menopause.
　Their BMD declined in parallel with that of the non-sport group. Moreover, our measurement of joggers revealed that the female group which continued jogging approximately 27 km a week on an average showed the greatest preventative effect on postmenopausal osteoporosis. It is extremely difficult, however, for the elderly in whom exercise related impact is small to acquire higher bone mass with gateball, though, it was considered that the synergistic effect of exercising and Ca intake should be expected in elderly people in whom sport related impact was limited.

DESCENTE SPORTS SCIENCE Vol.12/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE