Our experimental and clinical studies lead to the following conclusions: 1. The amount of exercise that has a favorable effect on bone tissue differs between males and females among individuals. 2. An appropriate amount of exercise has a favorable influence not only on weight-bearing bone but also on non-weight-bearing bone, provided there is a sufficient intake of calcium. 3. Exercise may prevent the bone loss in osteoporosis, but an increase in bone mass cannot be expected. The major aim is to increase bone mass before the achievement of peak bone mass in order to prevent osteoporosis. However, suitable weight-bearing exercise in osteoporosis is useful for the prevention of falls which may result in fractures, to increase muscle strength, to improve walking balance and coordination, and to prevent orthostatic hypotension.