1. The skeletal effects of physical training were studied in a controlled trial involving 31 healthy women (aged 50–73 years) with previous Colles' fracture of the forearm. The bone mineral content of the lumbar spine and both distal forearms was measured by dual-photon (153Gd) absorptiometry.
2. The participants were allocated to either a physical exercise group or a control group. The former group followed a standardized exercise programme, exercising for 1 h twice weekly during 8 months.
3. Twenty-seven women completed the study. Lumbar spine bone mineral content of the exercise group increased by 3.5%, whereas that of the control group decreased by 2.7%. The rate of bone loss in the control group equalled that of age-matched normal women.
4. The changes in forearm bone mineral content appeared to be independent of the exercise. The bone mineral content of the previously fractured forearm remained nearly unchanged. The bone mineral content of the uninjured forearm decreased on average by 3.5%.
5. The data suggest that physical exercise can inhibit or reverse the involutional bone loss from the lumbar vertebrae in normal women. Physical exercise may prevent spinal osteoporosis.