Gabe Mirkin, M.D.
How does exercise make bones stronger?
Bones are not static. Certain cells called osteoblasts
constantly bring calcium into bones to make them stronger and
osteoclasts take calcium from bones. Exercise increases the
rate that osteoblasts strengthen bones. Inactivity slow
osteoblastic activity to weaken bones. So any exercise that
places force on a bone will strengthen that bone.
If they live long enough, every woman and most men will
suffer from osteoporosis. Women who break their hips from
osteoporosis must have a hip replacement immediately.
Otherwise, they have a 20 percent chance of dying from
complications within a year. A study from Australia shows that
running strengthens the leg bones of both older and younger
women (
Medicine & Science in Sports & Exercise, October
2005.) However, the research shows that bones used in an
exercise are the only bones that are strengthened by that activity.
So running strengthens leg bones, rowing strengthens arms and
back, and lifting weights strengthen bones that are used for each
lift.
December 31, 2005