We wrote about first the four factors, which consist in the possibility of jumping higher - movement efficiency. Now is a time, when we will discuss about second factor - body composition.
There is a simple dependence - skinny people jump higher. Basically the leaner you are (low in body fat) and the less unnecessary muscle mass you have, the higher you should be able to jump.
Want to run faster and jump higher – reduce unnecessary weight. Less weight means you don’t need to produce as much power to jump the same height. It also often means you will move more freely. Your excess weight means that when you land there is high impact on your joints which can quickly lead to injury.
However remember, that you can not get into an obsession. We're talking about unnecessary weight!
Very important is also is the role excess muscles in your jumping ability. The reason for this is that a good portion of how much force you can produce is determined by the size of the muscle. Yes, more muscle should equal more power, but extra muscle mass becomes counterproductive.
You must balance your weight. - You should have a low fat and appropriate, not too many muscles, which help you attack with greater force.
When we need to reduce excessive body mass the next question is how do you do it? For both excess body fat and excess muscle it can be removed in two ways – it can be dieted off, or it can be burned off.
If you are eating 3000 calories a day and your body only uses 2500 you have a daily surplus of 500 calories per day. Either you will be eat less, or you will practise sport.
You also can't forget about being strong. You must have muscles. The body has two processes for getting stronger - neural improvements and increased muscle size. The first to kick in is usually the neural improvements. This is where your mind gets better at telling your muscles how to both work individually and with each other.
The second way that your body gets stronger is by sending out the hormonal signals to make your muscles grow bigger to accommodate that need. This takes a bit longer, but provided you get enough food and rest to allow the process to work, your muscles will grow.
Source: Volleyball Plyometric Training