My sons high school baseball practice started today. As I watched the players hit in the cage I saw one kid lifting his back foot and planting it in front of his other foot after the swing. This was a varsity player so I was taken aback on poor mechanics.
I found out that the coach is having all the players using forward momentum to get "more power". I was completely shocked especially after seeing my son do everything in his swing mechanics that was opposite of the proper way to hit a ball.
I told my son to keep swinging the correct way (see Science of Hitting by Ted Williams) and only satisfy the coach when needed.