Back pain and injuries seem to get all the attention, but there are also the upper extremities that practically everyone in the trades uses throughout the day: our arms.

According to the Bureau of Labor Statistics, one in four construction workplace injuries in 2010 were musculoskeletal disorders affecting the muscles, nerves, tendons, joints, cartilage or spinal discs. Major examples include carpal tunnel syndrome, tendinitis, and bursitis (two of these affect the hands and shoulders). A less common disorder, Raynaud’s Syndrome, results from nerve damage to the hand due to power tool usage.

“Most cumulative trauma disorders (CTDs) occur in the upper extremities, above the waist, and most arm pain is manifested in the hands and elbows,” says Wen Yau Jennie Yen, PT, DPT, CHT, a physical therapist at the Hospital for Special Surgery in New York. “But the main cause of the pain is often what happens proximally, in your spine and trunk.”

In other words, much of your arm or hand pain, numbness and tingling can be traced right back to the back. All of our peripheral nerves branch out from the spine, so injuries or nerve damage closer to the spine can result in strange sensations in your extremities.

So when a patient comes to Yen with complaints of numbness in the hand that sprung up while twisting for a layup or tossing a Frisbee at a family BBQ, she realizes the activity they name is likely not the root cause. “For example, numbness in the thumb may be associated with a part of the spine connected to a nerve that controls the muscles of the thumb.”

It’s not all in the back, though. Repetitive stress injuries resulting from repeated postures or activities using the shoulders, elbow, and hands are also very real, and may have accumulated over a long time (hence the name “cumulative trauma disorders”).

According to Yen, tight and tense muscles can easily impact the nerves. “CTDs usually have to do with muscles being tight and overworked, which affects the nerves and manifests as pain.”

Tool #1: Good body mechanics

It sounds obvious, but: to prevent CTDs in the arms and hands, it’s important to be aware of your body positioning.

For example, if you’re spending the afternoon nailing in two-by-fours, it’s better if you’re standing on a ladder and holding your arms in front of you rather than over your head, as the latter puts an unnatural strain on your shoulders. It’s also better if you can keep your wrists straight as much as possible rather than bending them all the day.

“Keep your center of gravity strong enough to help you,” says Yen. “Make sure you’re not reaching too much, and carry loads closer to the body.”

Of course, there’s work that simply requires holding your arms above your head sometimes (electrical) and bending your wrists (carpentry, plumbing)—but being aware of awkward positions, you can try to switch them up.

“Make sure your body mechanics are always working to your advantage,” Yen advises. “Once workers start getting tired, they get lazy about it.”

This brings us to another essential tool in avoiding injury: breaks.

Tool #2: Take breaks (even short ones)

According to Yen, breaks are essential, whether our jobs are physical or sedentary, for instance pecking at a keyboard for eight hours.

A break may mean sitting still and relaxing or standing, walking, and stretching. Or it might just mean shifting your position and continuing the activity using a slightly different muscle set or even with the opposite hand, arm, or shoulder.

“Even a few seconds of not doing an action unloads your spine and resets it a little bit, and gives that muscle a chance to rest,” says Yen.

Tool #3: Rebuild and release

Yen stresses the importance of building up strength in your trunk, which should bear the brunt of most of your movements, if you are using your body correctly.

“Strengthen your base to move better,” Yen advises, “or else you’re getting the power from your arms.”

Still, Yen warns that people with chronic pain are making a mistake if they think they just need to push harder. “People say, ‘My posture’s bad, I should strengthen’. But if they’re overusing their muscles, they also need to relax and stretch and lengthen.”

The upshot: you can’t do the same thing day in and day out, without frequent breaks, and expect no fallout.

“You can’t stop doing what your job requires of you to make a living,” Yen says. “But if you have pain, there’s something going on in the way you’re moving that’s using one muscle more than the other, and it needs to be watched—or switched.”

For more information on musculoskeletal disorders in the arms resulting from construction work and how to prevent them, check out this article in the Electronic Library of Construction Safety & Health.