You have camps because it's an easy way to make money. Truth it they are kids, if they want to run faster send them to a track coach. Parents don't see that and send them to you. A former bodybuilder now claiming to teach speed. BTW combine training is a joke. Let me guess you have them do the bench, jump up and down then run 40's and squat? WOW! breath taking!
Truth is the college kids have a base from real coaches in college, all you have to do is get them to then specialize for a few weeks to improve in those areas.
Well....if those kids ran track I would send them to a track coach, but none of those kids run track, most play football and since football and most sports like baseball, soccer, Lacrosse are all first step and 90% change of direction and deceleration, someone who does what I do would suit them better.
I had 2 athletes from USC in the NFL combines this year, can I make someone like that faster, hell no, but I teach them to be more efficient in their running mechanics and maybe teach them a better technique to help bring their times down. It's harder to teach kids than it is to teach a college JR or Sr. or pro because they've been there, but showing them how to relax when they run or adjusting mechanics in a drill WILL make them quicker in a change of direction drill. We don't teach them how to run 400m, as a matter of fact we rarely go beyond 20 yards because they don't have first step quickness they'll have a hard time making it in any sport. Besides....speed starts in the gym, not on a track.