Treadmill vs. Hitting the Road

In terms of building bone strength, they work equally well.

Q: Is walking on a treadmill just as good for increasing bone density as pounding the pavement?

A: Yes. Whether you're doing laps around the neighborhood or trekking on a treadmill, the crucial element is the same: weight-bearing activity.

"To build bone, you need to move your muscles and bones against the force of gravity," says Wayne L. Westcott, PhD, fitness research director. Eventually your bones adapt to the weight and the pull of muscles by producing more cells and becoming stronger. Although you'll reap bone-building rewards regardless, the harder the surface you walk on, the faster you'll get results. When the ground doesn't give beneath your feet, there's more impact and, therefore, more pressure on the muscles and bones, Westcott notes. You may want to opt for a concrete path instead of a dirt track, or a treadmill with a belt that's board-supported over one that gives. Remember, though, hard surfaces are best for walking, not running. Jogging on a rigid surface puts too much stress on joints and may cause injury. Regardless of your pace or the inflexibility of the surface, always lace up in quality, shock-absorbent shoes with thick midsole support.