A simple stretch can seem harmless.

Most people stretch their arms without giving it much thought. You might extend your elbow, pull your arm across your chest, reach overhead, or straighten the wrist after sitting for a long time. Usually, the movement produces nothing more than a mild pulling sensation.

But sometimes, a person can move just slightly beyond what their muscles or joints are prepared to tolerate and suddenly feel a sharp, unexpected pain.

The image accompanying this story shows an older man with a visibly unusual appearance around his arm and elbow, alongside a close-up of deeply wrinkled skin on the fingers. The image itself does not provide enough information to determine exactly what happened to the man, but the story raises an important question:

What should you do when a simple stretch suddenly causes sharp arm pain?

The answer depends on what the pain feels like, where it occurs, how quickly it appeared, and whether other symptoms develop afterward.

When Stretching Suddenly Hurts

Stretching should generally produce a feeling of gentle tension rather than sudden, severe pain.

A mild pulling sensation can be normal when a muscle is lengthened. Sharp, stabbing, burning, or intense pain is different.

Sudden pain during a stretch can happen for several reasons.

One possibility is a muscle strain. A strain occurs when muscle fibers or the tendons connecting muscles to bones are overstretched or injured. This can happen during exercise, lifting, sudden movements, or even an apparently simple stretch if the tissue is already tight or fatigued.

Another possibility involves the tendons around the shoulder, elbow, or wrist. Tendons transmit force between muscles and bones, and irritated or injured tendons can become painful when the associated joint is moved.

The pain may also originate from a joint rather than the muscle itself.

The shoulder and elbow contain multiple structures that work together during even basic arm movements. A movement that seems simple from the outside can place tension on several tissues simultaneously.

Why Age Can Matter

As people get older, muscles, tendons, ligaments, and joints can gradually change.

Muscle mass can decrease with age, while connective tissues may become less flexible. Previous injuries can also leave tissues more vulnerable to irritation.

That doesn't mean older adults should avoid stretching.

Quite the opposite: maintaining mobility and strength is an important part of healthy aging.

However, stretching should generally be gradual and controlled.

A person who has been inactive for a long time may not be able to safely perform the same range of motion as someone who regularly exercises.

This is especially relevant when a person suddenly tries to force a joint or muscle into a position it isn't accustomed to.

More stretching is not automatically better stretching.

A Sharp Pain Is a Signal to Stop

One of the biggest mistakes people make after experiencing sudden pain is trying to “stretch through it.”

That can be a bad idea.

If a movement produces sudden or increasing pain, stop the movement rather than repeatedly testing it.