(AP) – Attention, runners: your expensive shoes may not be doing you any favors.

A new University of Kansas study finds that the extra padding found in conventional running shoes may be changing the way runners strike the ground and could eventually lead to injury.

The Kansas City Star reports that University of Kansas researchers put high school athletes on a treadmill. Running barefoot produced forefoot striking, believed by many to be a more natural way to run.

Putting on conventional, cushioned-heel shoes led the runners to land on their heels — which some experts say can lead to knee and hip injuries over time.

So-called “minimalist” shoes that mimic the barefoot experience are catching on with consumers, but experts say anyone making the switch should go slowly to avoid injury.