Most people have heard the common refrain to lift with their legs, not with their back. That's good advice, McHugh said -- though sometimes, your legs aren't totally up to the job.
"Most of what predisposes you to throw out your back is actually tightness and inflexibility in the hamstrings and gluteal region," he explained.
Your hamstrings and gluteal muscles are a powerful team. "You can lift hundreds of pounds with those muscle groups," he said. By comparison, the paraspinal muscles, which run up and down your spine, are designed to lift maybe 60 to 80 pounds.
When you bend to pick something up, your leg muscles do a lot of the work. But if those muscles are tight and stiff, they might reach their capacity before you finish bending. The rest of the force is transferred to your back -- a recipe for straining your paraspinal muscles.
Baseball players are often most vulnerable to pulling a back muscle after a workout, McHugh said. After sprinting or lifting weights, their leg muscles can become tight and inflamed. Then they might bend to pick up something unsuspectingly light, like a duffel bag, and throw out their backs in the process.
"If you've just done a big workout, those muscles are all overworked, and you want to be extra careful with lifting mechanics," McHugh said.
Non-athletes with tight hamstrings are susceptible to this type of injury, too. And the older you get, the more prone you are to throwing your back out, he added.
Preventing Back Muscle Injury
The good news: Stretching exercises can help prevent back injury. That includes regular stretching to elongate the hamstrings and gluteal muscles, as well as exercises that stretch the lumbar spine.
While it's pretty easy to feel tightness in your hamstrings, it's a bit trickier to correctly perform exercises that isolate the paraspinal muscles, McHugh added. One helpful stretch, for example, is to kneel on all fours and roll your back like a cat.
Warming up before activity is also important, he added. "Coming in cold sets you up to pull something."
If you do pull a muscle, you'll usually recover with rest, time and anti-inflammatory medicine. But it's worth the effort to stretch your muscles and lift with care to avoid back injuries. "Throwing out your back can be really debilitating in the short-term," McHugh said.