(Just so you know, there was not a lot of content about the skeleton, so I opted not to include it. This is not a part of the essay)
Muscles are one of the most important parts of your body. They control every single part of your physical movement. From blinking to lifting things to maintaining posture, our muscles control all of it.
There are three types of muscles throughout the body: Skeletal muscles, Cardiovascular muscles, and soft muscles. Skeletal muscles are the main muscles, with almost every muscle being skeletal. The only exceptions are that the heart muscles are cardiovascular, and certain muscles around the intestines are soft muscles. Notice that skeletal muscles are controlled by the somatic nervous system and the others are controlled by the autonomic nervous system, which I found interesting.
For the rest of the essay when I refer to muscles, I am referring to skeletal muscles.
Muscles are what allows all mechanical movement of the body. Muscles stretch across almost every part of your body. There are three types of muscle movements: one muscle extends and the other contracts; the inverse (the first muscle contracts and the second one extends); and stabilizer muscles that help you maintain balance across your body. Within these there are also slow twitch and fast twitch muscles. The fast twitch muscles are built for high performance with low stamina, and the slow twitch muscles are built for low performance with high stamina. Most stabilizers are fast twitch. All the other muscles can vary whether they are fast or slow twitch based upon how you use them; A sprinter will have more fast twitch muscles in their legs than an endurance runner, typically.