We have a piece of equipment that looks like a ladder. There are 16 inches BETWEEN the rungs. This "ladder" is approximately 5 feet long and 3 feet wide. These are made of 1 inch metal tubing. We have one of these in each of the spots on our chute.
The player will get in his normal stance with his toe up against the first rung. On the whistle the player explodes through the chute. After the players get accustomed to doing this we put a defender in the chute. The offensive player must get him out of the chute. The player must put a foot in each opening. This requires the player to take a 6 to 12 inch step on his first 3 steps. It will not allow him to overextend on his steps.
Make sure the player puts a foot in EACH opening. Otherwise his first two steps will be too big.
This drill will improve body lean. It will also improve footwork and explosion off of the football.