1) Explosive movements in the weight room. Vertical jump is all about explosiveness and generating force from a position of almost no momentum depending on the situation. So power cleans, jump squats, and plyometrics are the best thing to train your vertical jump.
2) STRETCH. We can’t explode if we are super tense I need to have loose hips and be able to fire from my hips. I can’t do that if I’m stiff. 3) When you do regular lifts not explosive ones, lift heavier for low reps and focus on exploding. Jumping is an all out effort movement. That’s activating your fast twitch muscle fibers, s
o lifting a light weight for 20 reps is using your
slow twitch fibers. Doing a heavier weight for low reps like 3-5 (with good form) and being explosive activated your fast twitch fibers. If you can build those up your explosiveness will improve therefore, your vertical will improve.