There is a connection between the heel and the knee that is often lost in coaching. When the heel comes up, the knee naturally rises to its proper position.
Wide receivers require great acceleration coming off the ball and out of breaks. Fast foot turnover improves the first couple of steps that influence how fast an athlete can get to full speed.
Mini Hurdles provide speed training that focuses on acceleration through fast stride rate/frequency. For best results, set up 10 Mini Hurdles at 3-foot spacing. The Spatial Illusion drill uses 4-foot spacing.