Last month, we provided exercise swaps to help you train around (and prevent) a bum knee during leg day. This month, we’re following the same formula but gearing it toward guys with lower- back pain. Unfortunately, chronic lower-back pain has been estimated to affect 19.6% of people between the ages of 20 and 59. What’s more, the frequency of lower-back pain increases and peaks between the ages of 35 and 55. These are your prime years—in and out of the gym—so, if you’re in that 20%, use this guide to take advantage of them by making gains sans the pain.

Spine School

Your lumbar spine—which connects your midback to your hips—consists of five vertebrae and is supported by six ligaments, similar to beams in a high-rise. To avoid contact between vertebrae and absorb shock from everyday impact, fluid disks are set between each of them. Over time, these disks can experience significant wear and tear and, when combined with abnormal movement, can lead to a ton of unwanted injuries—osteoarthritis, degenerative disk issues, and fractured vertebrae, to name a few.

Spine Stumbles

According to Charlie Weingroff, a physical therapist at Drive 495 in New York City, “The three biggest opponents to spinal health are spinal compression, spinal shear, and flexion.” Spinal compression is when the disks are being pushed into each other, spinal shear is when one disk is sliding out of place, and flexion is the overextension of your spine. Exposure to these forces can lead to injury. “If you can minimize the impact of the three while maximizing force production, you’ve found a great alternative,” Weingroff says.

The Fix

First off, if you have orders from your doctor to stay out of the gym, then do so. That said, there are a lot of lower-back injuries that can be rehabilitated through physical therapy and tolerated with the right exercise selection. In fact, weight training will strengthen the muscle surrounding your spine, which can help protect you from future injury. You just have to know which moves to avoid; otherwise, you risk making it worse. Use the swaps listed here to maximize your leg day for pain-free gains.