Load-to-explode box jumps are not only extremely effective for increasing your vertical jump and leg power, but also for transforming and/or developing fast-twitch muscle fibers, which are needed in order to maximize muscle mass. Ladies, if you’re looking for some top secret bootybuilding shizzle then like and follow. No questions assed.
Up until the late 20th century, the vast majority of documented research into muscles and movement was done in a static environment using cadavers. Apparently, people had no common sense back then lol. Nowadays, we have a much better understanding of how the body works. Before any contraction there is an eccentric loading of the muscle that can be seen when bending your knees to jump, or when twisting your body left to swing a tending racket to your right.
Dropping from an elevated surface and then jumping, increases the load on the muscles in comparison to jumping straight up from the floor. The increased eccentric load will cause the muscles to explode with a bigger bang, which will increase your vertical jump.
Personally, I train legs for power (not strength), mass, functional ability and mobility. Power has helped increase mass, but never the other way around. On the flip side, power DOES increase strength and speed. However you can easily reverse the effects by not performing the exercises properly.
To prevent LOSING power, (1) NEVER use a weight heavy enough to turn the movement into a static one instead of an explosive one (keep it light); (2) NEVER do more than 8 repetitions per set, or continue a set once the explosiveness of your muscles has died out (whichever comes first); (3) rest for at least 90 seconds; and (4) only work power exercises into the very end of your program (the last one, or two exercises).