Then it must be that the hip flexors, hamstrings and possibly tibialis anterior (to a lesser degree) could be culprits in this equation. If that's the case, if I were LBSS (I might implement this regardless in my training) I would do 1 set of supine psoas leg raises (with cables), leg curls and toe raises at the end of each and every workout.
??? Muscles have nothing to do with this bullshit.
Jk. But on a serious note, how much would you expect his sprint times to decrease? 5.1s 40yd dash to ___ following a release of this inhibition?
I would expect less than a 0.1s difference in a 40. LBBS strength doesn't translate to good 40yd dash times without practice, or a good DLRVJ without practice, thus there should be focus on reactive strength imo. Of course, LBSS has a LOT of practice, so this is why some of us think it doesn't make sense. But...
Last week with LBBS we did some broad jumps into vertical jumps. I like this exercise because the athlete needs to produce forces vertically, after absorbing impact coming horizontally, quickly. It's also called a horizontal depth jump and is much more specific to a running vertical imo. The exercise looked novel for LBSS and he had some initial difficulty with it. Perhaps hip flexor inhibition played some role, but I think rather a lack of coordination and speed were the biggest weaknesses. Being able to transfer forces horizontally to vertically can be improved here.
Furthermore, his 2xbw LBBS is glute dominant. His SVJ is hip dominant. There are many more excellent knee dominant SVJs than hip SVJs - thus although he is strong, I don't think it's specific enough to a knee driven vertical jump, and I have to disagree with Lance that 2 inches on the back doesn't make much of a difference, I think it makes a giant difference. Even neck angle during a high bar squat or sprinting can make a giant difference in pattern of muscle activation. Just switching from vibrams to 100% barefeet makes a giant difference (extremely VMO dominant and no glute sensation at all to major glute sensation and more in the vastus lateralis), at least for me but I suspect for many people it would.
I don't think Raptor's suggestion could go wrong by any means, and if anything they would help strengthen the muscles, but I don't see how inhibition is the answer?
However if there is an inhibition I would suggest sprinting longer distances at a fast pace (like 60meters at least). I've noticed that the only times my hip flexors ever feel like they're inhibiting my stride is when I haven't sprinted in a while. After I sprint a little more my strides feel very loose and there is no burning sensation in my hip flexors, however without the addition of ankle weights or other stimuli, I cannot apply progressive overload. But... I don't think I have noticed differences in how the DLRVJ feels so I cannot confirm if hip flexor inhibition really hurts my own DLRVJ.
Apart from that, front squat are up next. High bar sucks for his traps, but front squats won't. Dno if he's had experience with those. And Bulgarian split squats Mike Boyle style instead of lunges because he can't do lunges b/c of toes.
Conclusion: I think it's worthy of consideration but I wonder how much of a difference it will make. How can releasing hip flexor inhibition improve his DLRVJ, by how much? Are we talking 1 inch, or 4 inches? Will it simply allow the hip and knee extensors to apply more strength or will it improve his form?