Well I see your point, and was expecting it... but again - even with me improving low bar squat 1RM by 20 kg or so... my high bar squat 1RM has remained at a the same grinding 140 kg if I'm lucky. And I feel like whenever I jump, off one leg or two legs, the amount of tension I get in those jumps at the knee level is the same tension I feel when I do high bar squats - they seem so specifically "connected" to each other. Oh, and it's the same tension or OVERLOAD should I say that I feel when I do half squats.
It's like I want to express the posterior chain strength that I have but I can't, because once that power reaches the knee level the quads can't stop it from going forward and collapsing. Combine that with my heavy bodyweight and calf weakness (as of late) - and you get useless posterior chain because it's like pushing in sand - the quads and calves give out and you lose all your "potential" power that the posterior chain is able to generate.
It's like pushing a ton of power on a pole in a pole vault but the pole is very weak at the middle and bends like crazy with no return of force... basically no stiffness whatsoever.
So despite the video that you put - I don't feel like my quads are doing substantial work out there at all - I just sink and control the descent in that squat using my glutes and hamstrings, where the quads are just pretty much isometrically "kinda" contracting.
I know how that sounds but that's what I feel. Can't describe it otherwise.
Again, to sum it up - the same overload I feel in the plant of a jump, regardless of technique, is the same overload I feel when I high bar squat. If I could work it out with the slower movement, which is the high bar squat - to make myself used to control that collapse that wants to happen - then that should translate into the jumps as well.
In the past I thought that maybe I'm just too quad dominant and training with the high bar squat is something that will make me even MORE quad dominant, and that the low bar squat would make sense in that situation - but now I'm starting to think otherwise.
If you look at any great two foot jumper - they all have their knees go way past the toes and the quad contribution in their jumps is tremendous. It doesn't mean I should be the same, but what it does mean is that I shouldn't have a problem getting in that position without collapsing. If I do, like I do now, then I just have sucky quads and they need to be improved.