Back-Round Check! - Tap into next-level total-body strength and supercharge muscle gains by learning when and how) to round your back in the gym.

Lift with your legs, not with your back. It's a cue many trainers use anytime you bend down to lift something heavy. It makes sense, too, since conventional wisdom holds that rounding your back with heavy weight leads to injury. But if you look closely at a strongman like Tom Stoltman hoisting a 300-kilogram (661-pound) Atlas stone, you'll notice that his spine isn't ramrod straight at all. Instead, he's almost hunching forward, curling his entire spine around the stone. And if you scroll fitness social media long enough, you may come across an exercise called the Jefferson curl, which asks you to stand holding a light barbell, then lower the barbell while simultaneously rounding your back as much as possible.

-  By Kristine Thomason

Lift with your legs, not with your back. It's a cue many trainers use anytime you bend down to lift something heavy. It makes sense, too, since conventional wisdom holds that rounding your back with heavy weight leads to injury. But if you look closely at a strongman like Tom Stoltman hoisting a 300-kilogram (661-pound) Atlas stone, you'll notice that his spine isn't ramrod straight at all. Instead, he's almost hunching forward, curling his entire spine around the stone. And if you scroll fitness social media long enough, you may come across an exercise called the Jefferson curl, which asks you to stand holding a light barbell, then lower the barbell while simultaneously rounding your back as much as possible.

Truth is, rounding your back when you lift can be safe, and learning how (and when) to do so can unlock your body's true strength. The technique has actually been used by powerlifters since the 1960s, says strength coach Dan John. It's increasingly backed by science, too: One study found that participants had less compression and total load on their spine when they rounded their back to lift a15-pound box from the floor.

Tapping into all this power requires you to ignore the ongoing social-media debates between round-back veterans and straight-spine zealots. Instead, focus on understanding the science of rounding your back by learning the answers to these five questions.

1. How does rounding your back make you stronger?