It’s been a while now…I don’t know of any off the top of my head.
Take a video of him running. Watch his start. If his heels are hitting right off the bat, he can speed up by getting more forward in his push off. Shorten his initial stride to get up to a faster speed quicker.
When he hits his full speed, his foot strikes should be directly below him. If his feet are hitting ahead of his body, then his foot strike is decreasing his speed.
If you have access to soft sand, have him sprint in the sand. He will get much faster much quicker. Also, in the sand, you can see his stride lengths. It’s easier to correct his technique…