What changes when you assess running on a treadmill?

Dan Pfaff explains the biomechanical differences athletes exhibit when running on motorized versus curved treadmills compared to overground running.

What changes when you assess running on a treadmill? In our latest Coaching Eye live session, Dan Pfaff discussed some of the differences he looks for when comparing treadmill and overground running. On a motorized treadmill, the belt is moving backwards underneath the athlete. Dan commonly sees athletes respond by reaching slightly further ahead at touchdown, effectively giving themselves more time to coordinate with the moving surface. The effect tends to be less obvious on a curved treadmill, where the athlete is responsible for propelling the belt, but the interaction with the surface is still different from running overground. Speed matters too. Dan noted that in their work with curved treadmills, they generally kept assessment at 90% of maximum velocity or below. Above that, the coordinative demands could begin to introduce too much noise into what they were seeing. So why use a treadmill at all? One major advantage is the amount of information you can collect relatively easily. Multiple contacts can be viewed from the front, rear, side and even axially, giving the coach an opportunity to observe how movement changes across repeated contacts and at different speeds. As Dan puts it, treadmill assessment has a place. It’s one layer of the assessment — rather than a direct replacement for what you see on the ground. 📥 To start developing your own Coaching Eye, we created a free introductory guide: Coaching Eye 101. It includes an ebook and a full webinar with Dan on how to watch movement with structure and intent. 🔗 Grab the guide here: loom.ly/uXtc61A