One of my pet peeves is young players that run around the pitch with floppy arms and a coach does nothing to correct it. It's a myth that you can't teach speed. Your not going to teach a slug to be Usain Bolt, but you can teach a slug to improve by a step, or maybe two, which makes a huge difference on the pitch.This is an interesting video that show the difference in running dynamics between a soccer player and a track sprinter. This is why we must train specific agility exercises that work for soccer and not specfic to track or American football.
How many soccer coaches have you seen teach a kid proper running form? First step is as important as first touch.