Last winter I struggled with hip pain when I ran on the treadmill, but all the problems cleared up when the weather was nice and I was back to running outside.

Yesterday while D.C. was being washed away by torrential downpours, a treadmill was the only real option if I wanted to get my run in.

The run started out just fine, but before I hit mile three, that nagging hip pain was back.

Over the winter I did everything I could think of to fix the problem. Foam roller. New shoes. Stretching. Nothing worked.

Since my treadmill issues haven't gone away after months of avoiding it, I researched what could be causing the pain and concluded that my form must change drastically when I run on a treadmill.

The last section of this article from Running Planet explained things well:

"Your running form should not change when you are training on the treadmill. Unfortunately, the moving belt of the treadmill can create havoc with your running mechanics. The moving belt can cause some runners to lean too far forward at the waist in an attempt to “keep up” with the belt. Other runners may run with an extremely “bouncy” stride or may run with a very short and tight stride. You can avoid these form problems by focusing on your running mechanics."

I think I probably lean too far forward and bounce too much on the treadmill.

Runners also tend to reach out too far with their legs, lengthening their stride too much and putting excess pressure on the hips when they're on the 'mill. I'm not sure I do that, but it's something to pay closer attention to.

Hopefully I won't have to run many more times on a treadmill this training cycle, but in case I do, I know what to look for in my form now so that I can correct it before it causes pain.

Are you a treadmill runner? Have you ever experienced pain switching from running outside to inside?