Our bones are living tissue that adjusts based on when and how it is needed. A new study, published in the Proceedings of the National Academy of Sciences, suggests that exercising during youth helps build bigger and stronger bones for life, and the effect lasts during aging.

The researchers from the United States and Australia examined the cross-sectional size of the upper arm bone torsional strength, bone mass and bone mineral density of the throwing arm of 103 Major League Baseball players at numerous stages of their careers. They compared the differences between the throwing and non-throwing arm of their arms measured at different points in their careers to the differences measured in non-baseball players.

The researchers found that half of the bone size and one-third of the bone strength was largely preserved when they conducted a cross-sectional of the bone.

Baseball players were used in the research because the muscles in the upper part of the arm twist, when they throw the fastball, and therefore twist the bone. This was discovered when the researched with computed tomography imaging showing the increase of bone size due to the twisting motion.

Professor Marcus Pandy, chair of biomedical and mechanical engineering at the University of Melbourne, says, “The current paradigm seems to be that if you increase bone mass, then you preserve bone strength over a lifetime, but we know that as we age the bone mass decreases.”

Professor Pandy does not believe the “use it or lose it” quote applies to the skeleton, though it does apply to the skeletal muscles.

The researchers even compared bone size and strength in players who continued to play baseball after their careers versus individuals who stopped playing completely immediately after retirement. They found that even former players at 90 years old still retained more than half of the throwing-related increase in bone size — around the same amount as those who continued playing — and around one-third of the benefits in bone torsional strength.

“The bone gets less dense and therefore it loses mass, but if you can preserve the size of the bone then you preserve the strength,” Pandy says.

Additional Resource:

Physical activity when young provides lifelong benefits to cortical bone size and strength in men