I agree with almost every post here. When I was younger I could dunk jumping off one leg and dunk in 8th grade. Just as other people said as I got stronger and heavier I turned to two foot jumping. I disagree that 2 legged jumpers are more explosive though, it is just a different type of jumping.
One legged jumping fluidly converts forward momentum into upward motion, this effect is significantly less with two footed jumpers. The other thing I noticed was that as I got heavier and spent less time sprinting I spent much more time in knee flexion trying to produce the force to jump, and this bothered my knee. Sprinting and one legged jumping are very similar in my opinion. Just practice both of them.
The one thing I will say is that for a heavy person, one legged jumping probably results in much higher forces than two legged because the loading of that one leg is extremely rapid, and as we know, the faster the better.
Lastly, I believe the calf is much more involved in one legged jumping than two and that that muscle in particular is vital to converting forward momentum to upward power…[/quote]
I think they mean explosive as in opposition to reactive. The force produced in two-legged jumping comes more from voluntary concentric muscle contraction (explosiveness), while the force produced in one-legged jumping comes more from the tendons/muscles being stretched and then springing back (reactivity).
Interesting point about converting horizontal force to vertical force. This process seems like it would be totally reactive, so the calf, or rather, the achilles tendon, would be more involved in any kind of running jump, whether it be one foot or two (as long as you are jumping correctly).