An exercise physiologist reveals the mistake many runners make — and it has nothing to do with legs or feet

Heather Milton, exercise physiologist at NYU Langone Health, reveals the biggest mistake many runners make. Following is a transcript of the video.

To maximize the amount of energy you are using when you are walking or running on an incline or not, is to maintain good upper-body form and that includes keeping your core engaged throughout the entire exercise as well as maintaining good arm-form. 

So you're moving in a hand-to-pocket position with your arms moving forward and back.

If you are swinging your arms, a lot of people tend to either keep their arms up really tight or let them go out to the side so we want to make sure that your arms are moving in the direction that you want to be going, whether or not you are on a treadmill or outside, and your hands swing down to about your hip level and come back up, so your elbow stays at a 90° and you are just swinging forward and back.

The hand-to-pocket position can improve your stability of the upper-body as well as help you to continue to maximize the amount of whole-body exercise you are doing when you are running rather than holding on if you are on a treadmill. 

When you see runners that have more of what we call cross-body position of their arms, that generally is an indication of decreased activation or maybe even weakness of the core musculature.