Closed chain exercises (where the hand is supported on a moveable or fixed surface) are considered to be safe in the early stages of rehab in patients with shoulder instability, and are supposed to increase proprioceptive quality and neuromuscular control. Many variables determine the level of difficulty of these exercises, such as the body weight loading the shoulder, the plane in which the exercise is performed, the modality (static or dynamic), the presence or absence of visual feedback, dual tasks, external perturbation etc…It is a challenge to progress an exercise in a smooth way, so the patient feels safe during the performance, and is challenged to maximally stabilize the shoulder within his or her capacity.
In this clinical pearl we like to suggest a visual representation of the progress, to be used by the clinician when progressing from one exercise to another. Imagine the Rubik’s cube as a 3-dimensional cube with on each dimension 9 little cube. Now try to imagine exercise progression in each direction: 1/ vertical top down: the load of the body weight, increasing load from no body weight over moderate body weight (for instance standing on hands and knees) to full body weight, 2/ horizontal left to right: exercise modality, from static (keep shoulder in position), over unstable surface (for instance wobble board) to dynamic exercise, and 3/ horizontal front to back: plane in which the exercise is performed, with the sagittal, the scapular and the frontal plane.
Changing only one of the 3 progressions at the same time allows us to gently progress the exercise, and gives us a rationale about how to design a new exercise. In other words, if you want to increase the difficulty of a closed chain exercise, think about Rubik’s cube, and never jump over a progression!