There are three types under which strength is classified. These are explosive strength, maximal strength and strength endurance. Maximal strength is defined as the level of force or strength that can be generated from one particular effort at a time. When the muscles freeze or contract in an effort to move an immovable object, it is called as static strength. Explosive strength, also called speed strength, is a measure of strength versus time. The ability to be strong for a long time is known as strength endurance. These are three types of strength that you should generally be aware of.