These days the deadlift is viral: On Instagram, #deadlift nets over 9 millions hits. And more big-box gyms like Gold’s and 24-Hour Fitness sport lifting platforms and colorful, standard-sized plates ideally suited for the move. For gym rats, nothing will ever replace the bench press as the yardstick for lifting prowess, but for serious lifters the deadlift comes close.

In theory, the deadlift couldn’t be simpler—bend over and pick up a loaded barbell off of the floor. But experienced gym-goers know that the mechanics of the move is full of nuances that are surprisingly hard to get right. One cue you hear from a lot from trainers is to “keep your lower back in its natural arch” throughout the lift—but the moment many lifters start lifting heavy weight, their lower-back arch is the first thing to go.

Why this might be is a thornier question than you might think. To answer it, we tapped Jordan “The Muscle Doc” Shallow (, a chiropractor specializing in sports and performance, and a sponsored powerlifter who can squat and deadlift in excess of 600 pounds. Here are his top five reasons your back goes out of whack when you pull that bar off the floor—and how to fix them: