Acquire a training bungee, or sled, and have the athlete do resistance running 50 yards for 3 reps, with 3 minute rests in-between. Then without resistance for 2 reps, 3 minute rest. The point is to have the athlete do the reps as fast as possible; practice with quality of speed, not quantity of reps.
I use the PlayFast system if anyone is interested, and I download custom programs from:
They could sprint hills, that works on raising their legs high and having to use their hamstrings. Another exercise that I like to do is called squat sprints. I have various different types of squat exercises that they line up and do, when they finish doing the squat they then have to run a 20 yard dash. Turn around and jog back. After 3 sets of different squats, the 4th set is a lunge that they do all the way down to the other end of the 20 yds and they walk back for a breather. I repeat the group of 4 series and then move on to a different set. I have a total of 12 different squat moves and 4 different lunges. This workout can take up to 45 min to do.