6. BACK STRAIN. Lumbar—aka lower-back—strains can have many causes, but one of the biggest culprits? Not paying enough attention to your warm-up and stretching, says David Fabi, MD, an orthopedic surgeon with San Diego Orthopaedic Associates Medical Group. "When not properly warmed up, the muscles of the back are not able to absorb the energy imparted to the back during weightlifting,” he says. “This is especially true when lifting heavy weights." Poor form—like arching your back while attempting a heavy bench press—will also cause strain.
Prevent it: Stretching, core strength and proper technique are vital to preventing back pain, says Fabi. "If you are not experienced, consult an expert or hire a personal trainer to teach you proper form and technique." For some lower-back stretches to get you started, see MF’s Injury Prevention for the Lower Back video.
7. HERNIA. Holding your breath while squatting may make it feel as if you can lift more weight, but all that increased pressure on your internal organs—not to mention the boost in blood pressure—can cause internal organs to punch through their encasings, says Weiss. “This pushes your organs into a place they don’t below—and is a major medical emergency.”
Prevent it: Long-term, strengthening your core stability and abdominal muscles is key for hernia prevention. And in the moment, make sure you’re lifting only weight you can handle—and check in with your breathing to make sure it's steady, says Weiss.