Here at We Run and Ride, we received an invitation to share information about a study done on treadmills. So I skimmed through the material and right away found information that intrigued me. The comparison between outdoor running and training on a treadmill has always been something I’ve been curious about. So this bit of insight jumped out:

It takes a 2 percent grade on a treadmill to approximate outdoor running.

Motorized treadmills pull their users forward instead of requiring the runner to propel themselves. In order to compensate for the treadmill’s momentum, NSCA strength and conditioning coach Derek Zahler suggests you “adjust the running surface to a 1 percent incline to execute your workout.”

And then bump it up one more. Running outside comes with wind resistance and environmental pressure, so running on the treadmill requires less energy. “Athletes training on a treadmill can compensate for this discrepancy by adding another [percentage point] of running surface incline,” he added.

Then I noticed a bit of informaton about shock absorption, which is something I’ve always wondered about as well.

“Running on a treadmill may have the advantage of absorbing some of the shock/loading to the joints, but it’s still impact exercise. Biomechanical abnormalities will, just like when you run outside, become apparent quickly with impact and repetitive motion. Low back, hips, knees, and feet will get almost just as much loading.”