All you want is to jump like Michael Jordan or Leonel Marshall. There are many aspects affecting your jump. Very important aspects are quality of your training and your weight.
Quality vs Quantity?
Most people have done some plyometric training to improve their vertical. That is a good thing! Jumping drills, foot-speed training, reaction drills all make a big difference to how quickly your nervous system responds to the demands. Any of my athletes know how springy, fit and fast they feel coming out of a cycle of power/speed training!
The thing to remember is that you must always choose quality over quantity. If you are not fit enough to have high quality over 6 sets of a drill or movement you MUST do fewer sets with greater quality. Never risk training a poor pattern or form for the sake of getting in more volume! Besides when would you ever do 30 jumps in 30 seconds in any sport (unless you are at the double dutch world championships)? Typically there are other movements, which provide some level of recovery, and then a supreme jump again. The only way you can keep repeating the supreme movement is because of the lower activity between.
Remember, in order for the quality to be possible make sure that you are properly warmed up and activated. Therefore, when it comes to jump form and staying true to the energy system that you typically jump with (anaerobic elastic), stick with lower numbers of jumps when training and make sure the form/quality
are impeccable! This is sure to train your nervous system to perform!
All weight is not created equal!
Ok, here it goes…a sensitive subject! Whether you are male or female this applies to jumping athletes. If you have finished growing and you are training with extra weight (fat) then be aware that it will impair your jump. No one should be under-weight since this will cause a slew of health problems, but too often there are athletes not eating properly and carrying extra weight. That extra weight is like carrying a backpack that will be a detriment to your jump! If you need to lose fat and you do it in a healthy manner while you continue training, you should notice an improvement in your vertical. If you are trying to put on muscle mass and you do so successfully, it may take a while to see your vertical improve but eventually it should if you have that muscle tissue functionally working for you!