Osteoporosis is a major cause of chronic disability in older women. Although the eiology of this disease is multifactorial, accelerated bone loss early in menopause may result in subsequent osteoporotic fracture.

To assess the effect of physical activity pattern on bone mineral density in women, we studied two groups of nonsmoking women with different exercise regimens.

There were ten women who performed aerobic(AER) exercise and eighteen women who supplemented aerobic with muscle-building activities(MB) for 50min/day for 4 months.

Resting energy expenditure, caloric, protein, and calcium intake, and total body weight were not statistically different among the two groups. No increase in bone mineral density(BMD) in both groups was appeared, but were found significantly decrease in urine pyridinoline(PYD) and deoxypyridinoline(D-PYD) level in both groups after training.

We conclude that exercise is a major determinant of bone remodeling and bone mass by both local factors and possible systemic factors.

The implications of these findings for the prevention of osteoporosis warrant further intervention.