Moving a joint through its full circle
Controlled articular rotations, or CARs, are slow active circles performed at the outer edge of a joint's range while the rest of the body stays braced and still. A shoulder CAR, for example, traces the arm through its largest possible circle under deliberate muscular control rather than momentum.
The intent is to actively explore and own the full available range, contrasting with passive stretching where an outside force moves the limb. The slow tempo and surrounding tension are what make the movement controlled rather than a casual swing.
What they are meant to develop
Practitioners use CARs to maintain and gradually expand active range of motion, to build control at the end ranges where joints are typically weakest, and as a daily assessment of how a joint is moving on a given day. Doing them regularly is also a low-load way to circulate fluid and keep tissues accustomed to full-range movement.
CARs come from the Functional Range Conditioning system and the strongest claims about joint health outpace the formal evidence, so they are best viewed as a sensible movement practice rather than a proven medical treatment. Keep them pain-free and consult a clinician for joint pain. This is general educational information.