Would there be a practical use in using a trampoline for jump/sprint training? Would it be similar to over-speed/assisted sprint training, in that, you can reach bigger jumps with the assistance?
I don’t think so.
I’m not sure what the benefits of overspeed training are supposed to be, though I think there’s a little bit of research showing that there might be a positive effect. But with overspeed, you’re increasing turnover speed through higher limb velocity/shorter ground contact time but you’re not actually increasing force into the ground. So it’s the opposite of a resisted load.
But maybe the overspeed effect is that it’s getting your body ready for the increased limb velocity/reduced GCT that occurs when you’re able to produce increased force into the ground; so that the coordination necessary for the faster turnover is embedded into your muscle memory when you do improve the CNS/muscular output for increased force production.
But you’re not even getting that hypothetical benefit from the trampoline jump. It’s just reducing the amount of force necessary to get X inches off the ground. I don’t see it but someone else could correct me if I’m missing something.
Aside from those valid points, so there’s really no benefit or practical use for it?
Try doing some jumps or runs on a trampoline and then do some reactive jumps (e.g. hurdle hops, depth jumps or something like that) on the ground afterwards. If you’re anything like me you’ll find that your ground contact time has drastically increased and it’s very difficult to get any height. My experience has been that the trampoline seems to re-programme my stretch-shortening cycle to something a lot slower and less powerfull.
Exactly, the biomechanics are vastly different. You’re teaching your body to increase ground contact time, because the deeper you get down the higher you get up.