Why your deadlift rounds and how to keep a flat back

Before we hunt causes, a dose of calm. Current research shows that a rounded back on a deadlift is not the guaranteed injury it was once made out to be, and some spinal flexion during lifting is normal rather than catastrophic. So this is not about fear. It is about performance and control: a flat, braced back transmits force better, keeps the load where your hips and legs can handle it, and gives you a stronger, more repeatable pull.

The distinction that matters is between a small amount of rounding you can control and a spine that folds because the position was never there to begin with. We are chasing the second one. When your back caves the instant the bar leaves the floor, or gets worse rep after rep, something specific is going wrong, and it is fixable.

Nearly every rounding deadlift traces back to one of four things, and often a mix. Work out which is yours before you reach for a cue.

If you cannot reach the bar with a flat back even at light weight, the issue is often at the hips and hamstrings, not the spine itself. Your body rounds the lower back to make up for hips that will not hinge far enough. Forcing a flat back through cues alone will not work if the range is not there.

• Raise the bar to a height you can reach with a flat back, for example pulling from blocks or plates, and lower it over time as your hinge improves.
• Drill the hinge with Romanian deadlifts and hip hinge practice, learning to push your hips back while keeping your spine long.
• Build hamstring and hip mobility gradually so you can reach a lower bar without your back giving way.
• Check your stance. A slightly wider stance or a sumo pull can shorten how far you have to fold to reach the bar.

Plenty of people have the mobility to pull flat but throw it away in the setup. They bend down and immediately jerk the bar before their back is tight, so the first inch of the pull happens with a soft, rounding spine. The fix is to slow down and build tension before you drive.

1. Set your feet and grip, then wait. Do not pull yet. Take your grip with straight arms and get your feet planted over your mid foot.
2. Lift your chest and set the back flat. Squeeze your chest up and think about making your whole back rigid and long before any weight moves.
3. Pull the slack out of the bar. Take the tension into the bar until you hear or feel it settle against the plates. Now your back is loaded and set, not slack.
4. Engage your lats and drive. Imagine squeezing oranges in your armpits, or pulling the bar into your body, to switch your lats on. This keeps the bar close so your upper back does not get dragged into a round.

That lat cue solves a huge share of upper back rounding. When your lats are off, the bar drifts forward, the load moves in front of you, and your upper back curls to chase it. Keeping the bar dragging up your legs with active lats holds you flat where it counts.

If your first reps are flat and your last reps round, you do not have a technique problem, you have a fatigue problem. As you tire, your brace loosens and your position decays, and grinding out those final ugly reps trains rounding under load, which is exactly what you are trying to avoid.

1. Stop sets before form breaks. Keep a rep or two in reserve so every rep you do looks like the first.
2. Lower the rep count on heavy deadlifts. Sets of five or fewer are easier to keep flat than long grinding sets of ten.
3. Reset between reps if you are doing touch and go and losing position. Take a moment to rebrace at the floor.
4. Manage total volume. If your back is fried by the end of the session, you may simply be doing too many hard sets.