RUNNING CAN BE TOUGH ON YOUR LEG JOINTS; with each stride, you bring three to five times your body weight down onto your feet, ankles, knees and hips. The running surfaces you choose play a big role in your risk for joint injury. To minimize your risk, you should look for surfaces that can absorb the shock of each step.

Here’s how some common running surfaces compare:

GRASS OR DIRT:
A good bet, as long as it’s smooth and even

SAND:
Not great; offers some absorption but doesn’t provide much “rebound”

CONCRETE OR ASPHALT:
Best avoided for long distances

TREADMILLS:
 Helpful if they feature a flexible deck