Weak Shoulder After a Rotator Cuff Tear? | Muscle IQ in Orem

The MRI showed the tear. Maybe you have already had surgery, or maybe you are still deciding. Either way, the shoulder still feels weak, and reaching for a high shelf or raking leaves in your Orem yard takes more out of you than it should.

It is natural to assume the tear explains all of it. Research suggests it does not always. In some people, the shoulder may feel weak partly because pain and irritated tissue have changed how the nervous system uses the muscles around it.

A Tear and a Weak Shoulder Are Not Always the Same Thing

In a UK study, researchers used ultrasound to sort the shoulders of 446 women aged 64 to 84 by tear size, then measured how hard each woman could lift her arm out to the side. Having a tear, on its own, did not explain weaker strength. Pain, however, was linked to about 11 percent lower strength. Strength differences tied to tears showed up mainly in women over 70.

In plain terms, what the scan shows and how strong the shoulder feels are not the same thing. Pain appears to matter too.

A Muscle Can Be Turned Down Without Being Torn

At Muscle IQ, we describe this with a simple picture. Your nervous system sets how hard each muscle is allowed to work, like a muscle tone dial. Pain and irritated tissue can turn that dial down. We call this muscle inhibition. A muscle that is turned down can test weak even when the muscle itself is intact.

A small study of people with long-standing rotator cuff tears looked at the deltoid, the large muscle that caps the shoulder. The researchers used a gentle magnetic pulse to measure how fully the brain was able to switch that muscle on. When patients tried to use it, the muscle was not switched on as fully as expected, and this showed up on both shoulders. The authors suggested that months of altered signals from the painful shoulder may change how the brain controls the muscle. They also noted that exercise programs relying only on effort may be less effective when this is happening.

It was a small study, so it points to an idea rather than proving it. It has not been shown that treating this restores strength. But it fits what we see in the clinic: a muscle that is physically fine and still not fully switched on.

After Surgery, the Same Question Can Come Up

A study of 221 people having arthroscopic rotator cuff repair looked at hand-tested strength before surgery. The surgeons graded outward-turning strength at about 4.4 to 4.5 out of 5, and lifting the arm forward at about 4.0 to 4.3. After repair, outward-turning strength improved. This kind of grading is a quick exam rating, not a precise measurement.

None of this means surgery is the wrong choice. For some tears it is the right one. These findings suggest that a tear alone may not tell the whole story of how strong a shoulder feels, and that a shoulder that still feels weak is worth looking into.

What Muscle IQ Checks

At Muscle IQ, a physical therapy clinic serving Orem and Utah County, the evaluation does not stop at the scan. Bring your MRI report if you have one. We test the strength of the muscles in your shoulder, shoulder blade, neck, and upper back, and look for muscles that are turned down and tissues that are stiff and irritated. Then we treat, retest, and see whether the muscle responds. You can read more about how we approach shoulder pain and rotator cuff problems.

If you are still weighing surgery, our earlier post on rotator cuff tear: surgery or strengthening walks through the research.

Not every weak shoulder comes down to inhibition. If you have sudden weakness after an injury, an arm that will not lift at all, or severe night pain, see a physician promptly.

A Tear Is Part of the Picture

If you have been told the tear is the reason, and that is that, it is fair to ask what else may be limiting the shoulder. When the limit includes a muscle that has been turned down rather than a muscle that is gone, there may be more to address than the tear alone.

Take control of your health today by calling Muscle IQ at (801) 310-0851 to schedule your first appointment.

Learn more at MuscleIQ.com.