A lever in Jiu Jitsu is used so a smaller opponent can put the same force on a person that a bigger person could without using a lever by increasing the distance the work is done over.
2. The legs are very powerful and you need to get past them so you don’t get taken down because the legs can easily control you, since they are so strong. You want to have control over them.
3. Their hips and shoulders are points of movement for your opponent. Controlling them restricts their movements and limits their ability to get control.
4. Submissions are used to put enough pressure on your opponents body that they give up and tap.
Why does Brazilian Jiu Jitsu want control?
You need control to force someone into a favourable position for yourself. Control allows you to restrict them and it stops them from being able to fight back.