In obese older adults undergoing weight loss, resistance exercise and combined resistance and aerobic exercise have no statistically significant difference in their effects on hip bone mineral density or bone turnover markers.

When older adults who are overweight lift weights, the force on their hip bones tells bone cells to stop producing a protein that blocks bone building. This lets bone-forming cells work better and slows down bone-breaking cells. At the same time, losing weight lowers a fat hormone that normally helps protect bones; resistance exercise prevents this hormone from dropping too much, which keeps bone breakdown in check. Adding walking or cardio does not change this effect because the bones still get the same mechanical signal and hormone balance from resistance training alone.