The Kinesiology and Biomechanics of the Freestyle Stroke (Part 1)

How many of us swim the freestyle? Probably most of us. We may prefer another stroke, but the freestyle is often considered the rudimentary basic stroke that we all start off learning.
How many laps of the freestyle stroke do you think you’ve performed? Hundreds? Thousands? Millions? And which muscles do you think you can thank for all those laps? Have you ever considered the kinesiology and biomechanics of the freestyle stroke?

Have you ever wondered what’s going on beneath the water and under your skin while all that swimming is happening? Do you every wonder how the “gears” are spinning? The muscular system is beyond amazing, and you can delve into the mystery of “how it’s done" right now!

The Catch

The catch is the first step of the freestyle stroke. It is the phase where your hand first hooks into the water to propel you forward.
In the photo above, the hand submerged in water illustrates this phase.
“The normal “catch” occurs when the forward hand enters the water as the upper trapezius elevates and the rhomboids retract the scapula [shoulder blade].”

1. Trapezius

The trapezius is a large muscle on the surface of your back that is shaped like a triangle.
There are approximately three layers of back muscles – superficial, medial and deep. And the trapezius is one of the top layers of back muscle (superficial). It starts at the base of your neck, lays over your shoulder, shoulder blades and center of your mid back.
It’s primary function is to stabilize and move the shoulder blade. However, it can also perform movement of the spine when the shoulder blades are stable.

2. Rhomboids

The rhomboids are a muscle group that lie deeper than the trapezius (medial). Actually, they lie directly underneath the trapezius. They are smaller in size and they are shaped more like a quadrilateral.
They are located in between your shoulder blades and attach to your spine as well. The rhomboids are responsible for retracting your shoulder blades (pulling them in towards the center of your back).

Early Pull-Through

The early pull-through is the second step of the freestyle stroke. It is the phase where your arm begins to pull through the water.
“The serratus anterior protracts, rotates the scapula up, and is highly active from this point in the catch and through the pull. These opposing actions hold the scapula in place.”

3. Serratus Anterior

One side of the serratus anterior muscle attaches to the surface of the 1st rib to the 8th rib. The other side of the serratus anterior tucks under the shoulder blade on the inside of your body. Visually, you would recognize it as a muscle that runs along the side of your chest under your armpit.
This muscle has a couple nicknames. Such as the  “big swing muscle” or the  “boxer’s muscle.” Both names are references to the main action of this muscle…”because it is largely responsible for the protraction of the scapula — that is, the pulling of the scapula forward and around the rib cage that occurs when someone throws a punch.”

So Many More Muscles…

We’ve already hit on three of the muscles that play into the freestyle. And guess what…there are LOTS more. So many more in fact that you’ll have to stay tuned and watch out for the next blog post to learn the rest!
So, how interesting is all this information? Did you know all these muscles existed in your body? Isn’t the human body amazing?
If you’d like to leave any comments with more amazing facts about the human body, feel free in the section below.