Kinematic chain

Most movements involve more than one joint. These combinations of multiple joints are referred to as a 'kinematic chain'.

A distinction is made between an open, a closed, and a semi-open kinematic chain.

Open kinematic chain

In an open kinematic chain, the terminal joint moves freely in the air and is not restricted or held. This type is seen mainly in the arm, but a kicking motion is also an example. The end segment then moves freely in open space.

Closed kinematic chain

In a closed kinematic chain, the terminal joint cannot move freely. The most common form of a closed kinematic chain is the stance phase during walking. The foot is fixed between the ground and the rest of the body and therefore cannot move freely. Squats with the feet on the ground and push-ups with the hands against the wall are also examples of movement in a closed chain.

Semi-open kinematic chain

The semi-open kinematic chain lies in between. The joint appears to move freely in space but is still attached somewhere. For example, when you do thigh exercises in the gym on a machine where the feet dangle above the ground (leg extension). Or when you do arm exercises with a pulling machine.