It sure does matter. Even under the best circumstances up to half of all rotator cuff repairs tear again. During the first six weeks, the muscle isn’t really reattached to the bone. It’s just held in place by tiny sutures. It takes awhile for the tendon and bone to knit back together.
Too much load or too much strain can pull the stitches right through the tendon. Surgeons have a pretty good idea of how much their surgical repair can handle. It’s best to follow their instructions very carefully. Patients should ask before doing more than the surgeon advised.