How Muscle Contraction Works

Have you ever wondered how muscles work? What the actual process of getting your water bottle to your mouth requires?

A skeletal muscle includes everything from end to end (one tendon and bony attachment to the next). The actual protein where contraction takes place is called a sarcomere, but it’s so tiny, you need a microscope to see it.

Sarcomeres are bundled up and wrapped in a layer of fascia called the epimysium. At this level, it’s called a muscle fiber. A single muscle can have anywhere from a dozen to hundreds of muscle fibers within it!

Bundles of muscle fibers are called fascicles – we can see these with the naked eye. The fascial covering of the fascicles is called perimysium.

An individual sarcomere has thick and thin myofilaments known as myofibrils. These are the chain-like proteins that pull against one another to generate force.

As a side note, they can only pull, NOT PUSH! Pushing happens because muscles on the opposite side of the joint are pulling to change the orientation of the joint.

Cool, right?

So how does muscle contraction happen? The brain sends a signal via the motor nerves that causes a chemical reaction to take place at the sarcomere. The thick filaments within the sarcomere then pull the thin filaments towards the center of the sarcomere (known as the M-line). If enough sarcomeres shorten in sequence and at the same time, muscle contraction happens.

Learn more about how muscles work in this recent episode of Anatomy with Alex. Watch below now!

Watch my latest episode of Anatomy with Alex (below) to learn:

• What muscles do
• How muscles generate force
• What a sarcomere is and why it matters
• How muscles can only pull, not push

Tune in every Wednesday at 3:15 pm PST on the AE Wellness Facebook Page for Anatomy with Alex, my weekly show where I teach you anatomy and physiology in ways that are relevant to you in your life so you can maximize your mobility and live pain-free in your body.