I coach an extremely powerful sprinter who runs high 6's in the 60m, but only 11.4's in the 100m because he cannot seem to run relaxed. He runs tight and hard. He's a senior now and will play D1 football, and a good indoor season would help. He just wants to have a breakout year because he knows he's much faster than his times.
We've tried many different things to get him to run relaxed:
-buildups from a slow, relaxed jog
-55m sprints
-sprints with partner in the lead
-sprints with partner trailing
-visualization (although I don't think he's too good at that)
-overspeed
-breathing techniques
-etc.
If anyone could help, I'd really appreciate it. We've been struggling with this problem to two years now and I'm searching for anything. Thanks.