What the press asks of the lower back, and what no study has measuredEmerging evidence
In a strict overhead press the bar goes from the front of your shoulders to straight overhead while your trunk stays still: the site's press guide teaches squeezing your glutes, bracing with your ribs down, and no knee dip or leaning back. To finish overhead, the shoulders lift fully and the upper back extends a little: raising both arms extended the upper back by about 13 degrees on average in 21 men, varying a lot between people. In 10 people imaged while raising one unloaded arm, the upper back and lower neck curves changed, with no evidence of a change in the lower back.
No study has measured lower back movement or load during a standing barbell press, or counted back pain from it. That a lower back which arches under the bar is compensating, most often for a heavy weight, tiredness, or shoulders and an upper back that don't reach overhead, is our reading of these imaging and posture studies: in 31 men holding a swimmer's arms-overhead position, less shoulder range and less deep tummy muscle activity went with a bigger lower back arch, though that study measured one moment, in a different posture.
Sources 1, 2, 3
Who gets it: lifters' backs often hurt, but the press isn't namedEmerging evidence
Across weightlifting and powerlifting, the spine, shoulder and knee are the commonest injured areas; in powerlifting, the lower back made up 30.8% of injuries where reports gave counts. In elite weightlifters, who press and jerk overhead, 74.6% of back injuries were strains, and 90.5% of all injuries cost a day or less. No survey names the overhead press as the cause of a back injury; in Swedish powerlifters, injuries began in squat, bench and deadlift training. Belt users had more lower back injuries in 245 powerlifters, an association likely tied to heavier lifting.
It tends to bother lifters on heavy or long sets, when they lean back to grind out the last reps, after a jump in load, or with a back already sore from squats and deadlifts (our reading).
Sources 4, 5, 6, 7, 8
Arching, the facet joints and stress fracturesMixed evidence
From mid-life, pain on arching is often put down to the small facet joints at the back of the spine. They may account for 15% to 41% of low back pain, but a single numbing injection gives false positives in 25% to 45%, and the history and examination can't identify them.
In young athletes, a stress fracture of the spine (spondylolysis) is common: it was found in 41.7% of athletes with low back pain across 9 studies (average age 16, with very mixed results between studies) and in 30% of 1,025 adolescent athletes with low back pain. It usually does well when it's found, which is why a young lifter whose back hurts more arching back, and doesn't settle, needs checking.
Sources 9, 10, 11
Bracing and the pressure in your abdomenEmerging evidence
Bracing raised the pressure in the abdomen far more than drawing the tummy in (116 against 10 mmHg in 7 men). Raising that pressure stiffened the trunk by 21% to 42% in a sudden-release test in 10 people, and bracing cut movement at each level of the lower spine under a sudden load by 45% to 94% in 16 people; in a computer model, the effect depended on posture and task. Breath-holding pressures in the overhead press are modest (30 to 50 mmHg at the mouth in bodybuilders), far below squats and deadlifts.
These are lab measurements of stiffness and pressure. Trials rarely compare bracing with other approaches, and none tests bracing against back pain in lifters.
Sources 12, 13, 14, 15, 16, 17, 18
Rare but serious: a hernia, the heart and the nervesStrong evidence
Straining can bring on a hernia: the NHS names lifting heavy weights among the causes of a femoral hernia, a small lump at the top of the thigh in the groin. A femoral hernia with very bad tummy pain, being sick or not being able to fart or poo is a 999 call; any other hernia with pain in or around it needs NHS 111. Shoulder or arm pain with chest pain while pressing can be the heart, also a 999 call.
Numbness around your genitals or bottom, new trouble peeing or controlling your bowels, or weakness or numbness in both legs needs 999 or accident and emergency (A&E): the NHS lists these with back pain. All of these are rare.
Sources 19, 20, 21, 22
When a scan or test mattersStrong evidence
Not usually. The National Institute for Health and Care Excellence (NICE) says don't routinely offer imaging for low back pain outside specialist care. In 3,110 people without back pain, disc bulges showed on scans in 30% at 20 and 84% at 80, so a scan report has to match your symptoms.
Tests matter with the warning signs, for a young lifter whose pain is worse arching back and doesn't settle within a couple of weeks, and for sudden pain after a minor strain in someone at risk of thin bones.
Sources 23, 24
How it usually goesStrong evidence
No study follows back pain from the overhead press. In new low back pain, average pain fell from 52 to 23 out of 100 within 6 weeks, to 12 at 26 weeks and 6 at a year, across 33 groups of people (11,166 in all); in pain that had already lasted a while, it fell from 51 to 33 at 6 weeks and 23 at a year. The NHS says back pain usually improves within a few weeks. In Swedish powerlifters, only 16% of those injured stopped training completely. No one can promise a date.
Sources 25, 22, 7