Exercise — particularly certain types of weight-lifting and jumping routines — has been shown to reverse bone loss in in active, healthy, middle-aged men.

University of Missouri researchers say such workouts could offer a viable way to combat osteoporosis, at least in men. Although the conditions strikes more women than men, nearly two million men in the U.S. have the condition, and 16 million more have low bone mass, studies have shown.

But by engaging in such exercises for at least six months, men may be able to prevent the development of osteoporosis by facilitating bone growth, according to the study published in the journal Bone.

"Weight-lifting programs exist to increase muscular strength, but less research has examined what happens to bones during these types of exercises," said Pam Hinton, an associate professor and the director of nutritional sciences graduate studies in the MU Department of Nutrition and Exercise Physiology. "Our study is the first to show that exercise-based interventions work to increase bone density in middle-aged men with low bone mass who are otherwise healthy. These exercises could be prescribed to reverse bone loss associated with aging."

For the study, Hinton and colleagues studied 38 physically active, middle-aged men who completed either a weight-lifting program or a jumping program for a year. Both programs required participants to complete 60-120 minutes of exercises each week.

The men also took calcium and vitamin D supplements throughout their training programs. The researchers measured the men's bone mass at the beginning of the study and again at six and 12 months.

The results showed the men’s bone mass significantly increased after six months of completing the weight-lifting or jumping programs.

Hinton said the study results do not indicate that all kinds of weight lifting will help improve bone mass, but that targeted exercises made the training programs effective.

"Only the bone experiencing the mechanical load is going to get stronger, so we specifically chose exercises that would load the hip and the spine, which is why we had participants do squats, deadlifts, lunges and the overhead press," Hinton said. "Also, the intensity of the loading needs to increase over time to build strength. Both of the training programs gradually increased in intensity, and our participants also had rest weeks. Bones need to rest to continue to maximize the response."

The study was funded, in part, by the National Institutes of Health