[reckoner2]

How is this possibly true? I've increased my vertical jump by nearly two entire feet through years of training in volleyball. Everyone can increase their vertical just like they can increase their squat. It's a full body compound movement.

[e9]

I think he is referring to method NBA teams select newcomers. They take well trained young person and they have them do vertical jump. Because they are well trained, their vertical jump will not improve much because there is genetic component to it. But if you are average then of course it will improve with time as you do training, for example if you lose weight you can jump higher or if you practice and improve nerve-muscle connection that will increase your power output it will also improve your jump. But at the end of the day there is genetic limit for the most part, but just like with everything there are probably exceptions...

[z3t4]

Kinda like IQ test, if you train specifically for it, you can get better. Vertical jump is a good measure of power, same as a IQ test is a good test of intelligence.

[maaksool]

if this was the case, every NBA player would have a 48" vertical jump. Every 100m sprinter would be running sub 9.8 seconds.

Speed and power is entirely genetic. you're either fast or not. you can either jump high or you can't. you can improve it but only by slim margins.

Strength however, can be trained and improved greatly and well into middle age, which is why barbell training is so popular.

[CalChris]

Also very age dependent.

[BrandoElFollito]

The great advantage of volleyball is that it actually teaches how to jump.

I played volleyball recreationally for years and the jumping with arm swing became muscle memory. Last week I was teaching my 10 yo son some volleyball basics and I realized how a few extra movements can impove one's jump (specifically the singing and its timing).