I wasn't sure about the idea of my soccer players, ages 12 to 13, running with parachutes. I wasn't sure if they would put out the effort OR if the things would really make a difference. Turns out, my players LOVE them! They almost fight for more opportunities to race with them on. And in just two weeks of use I saw marked improvements in everyone's running speed. I would recommend these to anyone of any sport that requires sprinting. There is no doubt whatever your current speed, training with these will increase it.