Your body is full of levers and if you’re familiar mechanisms (or not) all three classes are found somewhere in your body.
- Class 1 levers are like a see-saw with the fulcrum in the center where you push down and the opposing load is also pushing down.
- Class 2 levers are like wheelbarrows where you pull up on the handle with the dirt load pressing down between you and the fulcrum, which is the wheel.
- Class 3 levers are like a gate where you push between the fulcrum on the wall and the load which is the side pivoting side of the gate.
Some may ask, “Where can we find these levers in the body?” Others ask, “Why does this matter?” I’ll address both.
This matters because if we recognize the function of levers then we understand the function of specific joints in the body mechanism. On top of that if we recognize function we can also recognize dysfunction. It answers questions like, “What can the shoulder joint do?” and just as importantly, “What does the shoulder joint not do?” This way we can keep movements safe and effective.
If you’re still with me you probably are really into mechanics, so let’s look now at the mechanics of the body.
Class 1: The head actually see-saws like a class 1 lever over the top of the spine. The splenius muscles pull down on the back of the head and the skull tilts over the spine so that the front of the head raises. Conversely when the splenius muscles relax the weight of the head tilts back over the spine and drops forward.
The head actually see-saws like a class 1 lever over the top of the spine. The splenius muscles pull down on the back of the head and the skull tilts over the spine so that the front of the head raises. Conversely when the splenius muscles relax the weight of the head tilts back over the spine and drops forward.
Class 2: The calves are a class 2 lever that lift the heel off the ground. The pivot point is the forefoot and the load comes between the muscle and the pivot point.
Class 3: The bicep works as a class 3 lever where the muscle connects between the pivot point and the load.
Movements that use one lever are called simple movements. Some examples are bicep curls, tricep extensions, leg curls and extensions, calf raises, and so on. These can be useful lifts but training levers only in isolation is not as relatable to functional movement as complex movements. CrossFit appreciates and utilizes complex movements as much as possible, or movements which require more than one lever. Some examples are squats, presses, and pulling motions. Next week we will look more at complex movements such as these and how multiple levers can work together.