Exactly which muscles are most important for improving the vertical jump is still relatively unclear, and may differ between individuals. Clearly, the spinal erectors, hip extensors, quadriceps, and calf muscles are all involved in the jumping movement, and the hip extensors and quadriceps are likely the prime movers, but which of the hip extensors is the primary muscle is very unclear. Importantly, since force production is required right up until take-off, the lower body muscles must produce force from moderate through to short muscle lengths, which differs from the barbell back squat exercise.
In the 2011 NBA contest, Los Angeles Clippers power-forward Blake Griffin completed a self-pass off of the backboard prior to elbow-hanging on the rim. A number of other variants of the elbow hang have been executed, including a lob self-pass, hanging by the arm pit,[23] a windmill,[24] and over a person.[25] Most notable are two variations which as of July 2012, have yet to be duplicated. In 2008, Canadian athlete Justin Darlington introduced an iteration aptly entitled a 'double-elbow hang', in which the player inserts both forearms through the rim and subsequently hangs on both elbows pits.[26] Circa 2009, French athlete Guy Dupuy demonstrated the ability to perform a between-the-legs elbow hang; however, Guy opted not to hang on the rim by his elbow, likely because the downward moment could have resulted in injury.[27]
After four months of failing to pull off anything even resembling a real dunk, the planets aligned on Aug. 9: After at least 19 failed attempts that afternoon, I dunked a soccer ball on a middle school court whose rim measured 9' 11". (The original basketball, incidentally, was a soccer ball, property of Dr. Naismith’s employer, Springfield College.) Video from that afternoon shows me standing there, looking confused, in the moment afterward. Did that just happen? Failing had become so routine that even this small success felt foreign.
We have two diferent vertical jump bands that you can use as a volleyball player. The first bands are the M.V.P. Pro bands that are attached at the heels and a belt around the waist. These vertical jump bands can be worn during practice so everytime you jump your are improving your vertical with the resistance provided by the bands. These bands are best if you are 5' 6" or taller.

A second, more efficient and correct method is to use an infrared laser placed at ground level. When an athlete jumps and breaks the plane of the laser with his/her hand, the height at which this occurs is measured. Devices based on United States Patent 5031903, "A vertical jump testing device comprising a plurality of vertically arranged measuring elements each pivotally mounted..." are also common. These devices are used at the highest levels of collegiate and professional performance testing. They are composed of several (roughly 70) 14-inch prongs placed 0.5 inches apart vertically. An athlete will then leap vertically (no running start or step) and make contact with the retractable prongs to mark their leaping ability. This device is used each year at the NFL scouting combine.