What exercise would best improve my vertical leap?
Just exercise the quads. Do electric chairs (when you put your back to the wall, and have your legs bent at a 90 degree angle, kind of like you’re sitting without a chair), squats, and do a lot of stretching. Also, try jumping repeatedly for a certain amount of time, every day. Then, you can see your progress and how much work you have to keep doing. Remember to have rest periods after your exercise, maybe exercise every other day. Also exercise other parts of your body, so you can use your arms and upper body to increase the length of your jump.