Two different concepts that are used not only in the strength training world but also in the movement world in general are the concepts of the CKC and the OKC. These terms are defined below.
1. Closed Kinetic Chain (CKC) – The Periphery are fixed and the Center is manipulated (think of a push-up, the hands and feet are fixed to the ground and the center of the body moves up and down)
2. Open Kinetic Chain (OKC) – The Center is fixed and the Periphery is manipulated (think of a bench press, the center is fixed on the bench and the arms move up and down)
In the above image, you can see two different balance tasks. One in the OKC environment and the other in CKC environment. Before you read any further, I would like you to see if you can discern which one is OKC and which one is CKC and WHY? I will give you some time…
Did you get both answers right? Both the mechanism and the reason?
The slack lining (right picture) is an example of balance in the OKC. Why? because the periphery (legs/feet) are not fixed, they are free to move as the slack line moves and the center of the body is more or less fixed in space.
The rail balancing (left picture) is an example of balance in the CKC. Why? because the periphery (legs/feet) are fixed on the rail, they are not free to move but the center of the body is the part that moves to find equilibrium.
Now, why is this information useful? Understanding the different mechanism actually changes how we become good at the task. In the balance example between rail balancing and slack lining, these mechanisms of balance are completely different. In the rail balancing, we need to orientate our center of mass to stay over the base of support. While in the slack lining, we need to keep the center fixed and move the base of support over the center of mass. If we move the center of the body to maintain balance in the slack line, we will fall.
When you are performing different movements, think is this a ckc or an okc movement and why. The answer is not always so clear.