Research suggests the effects of weight-bearing exercises as a teenager can offer benefits that last for more than 40 years.
Researchers led by Dr Takeru Kato, from the Suzuka University of Medical Science in Japan, found that exercises such as handball, softball and tennis kept bones stronger for many years.
The study questioned 46 women aged 52 to 73 about the types of sports they played between the ages of 12 and 18. The women were grouped according to whether they did weight-bearing exercise, non weight-bearing exercise or no exercise at all.
Tests were done on the size, shape and structure of the spine and the femur, including bone content and mineral density.
The results showed there was no difference in bone mineral density, but those who had taken part in weight-bearing sports had significantly greater bone mineral content.
The study also found that their thigh bone area was larger, meaning they were more able to withstand fractures.
Researchers wrote: "In middle-aged women, weight-bearing exercise during growth affects bones, and these effects may be preserved as bone mineral content, geometric and structural advantages of bone strength even after 40 years."