more and more it seems the vj is really a quad dominant movement and the energy being trasferred through the ankles and calves so they need to be strong, elastic, rigid or whatever the term is forgot the term, but yea seems like what kelly says about it is point on that it might be a quad dominant mvmt but if you only develop those quads your gonna end up getting some knee pain or something for the muscle imbalance and you need strong glutes if you want to stay healthy
there are too many quad haters in s&c
regardless of what you actually have to work, there's one thing that can be certain you need to improve:
- maximal strength in a "squat movement" (full, half, whatever)
- explosive strength in a "squat movement" (jump squat, dj's, rea, etc)
- improve maximal & explosive calf strength (dj, reactive, calf raise)
so, what actually muscle groups that is improving doesn't really matter, it just comes down to the movement.. but in each of those movements, hamstrings / glutes & quads will all be strengthened to produce force.. chances are, the quads and glutes will experience the most strength increases, even though one would experience pretty significant hamstring soreness while progressively overloading.
other things that can't be forgotten, just to make sure i don't leave it out in case anyone gets gung ho on only focusing on those 3 things:
- improving fitness
- jumping
- upper body strength/power (push/pull)
- sprinting
so ya, regardless of what is actually most important in terms of 'minutia', improving strength in certain movements is fundamental, regardless of advanced kinesiological/anatomical/physiological mental masturbation..
but ya, in terms of running or standing vert quads play the most important role.. even in sprinting they are so very important, to be able to land leg locked and absorb all that force to help transfer through to hip extension and plentar flexion is a very important role.. there's a reason people get 'quad dominant' -> they are just used immensely in every movement.. you can do all types of short accel & jumps and barely hit the glutes/hams, but you for sure will hit the quads/calfs HARDCORE.. extend those accels out to MAX-V (50m+ , 200m ,100m etc) then you get considerable hamstring/glute, but how many vert trainees are doing those kinds of sprints? not many... most are addicted to basketball and we know what kind of sprinting is involved in that, definitely not enough to maximally recruit the hamstrings/glutes.
peace