From our filming of top level Collegiate lacrosse, we are seeing these Power Shafts appear across many programs throughout the nation. The heavy trainers are used for running and foot speed drills and the light trainers get heads attached and are used in shooting, sliding and goalie drills. We would recommend these shafts for players coming up from the ranks of JV through college and then on to elite play. A real breakthrough from famed Coach Rotanz.