The main source of jumping ability is the explosive power of legs ... nothing can improve the jumping speed better than practicing legs ... I'll teach you a simple method.

Go to the gym and squat, but don't squat to the end. The weight of 8- 12 group and 5 groups is the best for you to squat just now ... then, put a barbell on your toes, and your feet are shoulder-width apart. Then put on a barbell. Weight is the heaviest weight you can resist/then point your toes to the highest place you can rise ... 20 -30 in each group, 5 groups, and your little leg hurts for 2 weeks. That's how I practice. Oh, by the way, the first time will definitely be excessive, so the muscles will have a painful period of 3-5 days, but stick to a small load and wait for the painful period to pass these days.