There’s an old joke where the patient says, “Doctor, it hurts when I do this…”. Tai chi gives the same response as the doctor, who says “Well, don’t do that.”
Tai chi engages the body’s natural healing mechanisms, which depend on both sensitivity and activity. If a movement makes you feel light-headed, aggravates an injury, or otherwise triggers negative internal feedback, then don’t do it. However, this is not a license to be passive or stagnant; instead engage what you can engage, and move in ways that don’t trip your body’s internal alarm systems. It is not a matter of enduring, but rather discovering the freedom you have within your constraints, which lets you gradually expand your range of motion and strengthen your body’s weak points. Practice moving in such a way that you could continue to do so for an hour, even if you actually only do so for five minutes. If you find a movement that you can’t endure, ease up, slow down, make changes until you are comfortable, but don’t simply give up. It is within a state of comfortable flow that you will access the resources that will accelerate your body’s healing capacity.