Prevent Stepping with the ball

Can someone advise on approaches to stop someone persistently stepping with the ball? It is proving almost impossible!

When doing a simple running and catching excercise drill, tell them to land on their left foot, or their right foot. Another idea is to get the whole team in lines and get them to jump landing on one foot and pivot. then get them running E.g blow your whistle and tell them to face the building or the trees

One really good thing I use is putting a pebble in their shoe, this helps remember what foot they land on. To be honest they learn really quickly as they get a sore foot from landing on it.