What no study has counted, and what the lab studies showEmerging evidence
No study counts what causes shoulder pain in dips, and none has tested depth, lean, grip width or elbow position against pain. So the map on this page comes from what each condition is known to do, two lab studies, a gym survey, case reports and health-service pages.
On parallel bars you hold all your weight on straight arms and lower by bending your elbows; the upper arm swings back behind your body, so at the bottom the shoulder is close to the end of its backward range (extension) while it carries your weight. In a lab study of 13 experienced men, bench dips reached 101% of the shoulder range each man reached when tested lying still, bar dips 88% and ring dips 69%; bench dips go furthest back because the trunk stays upright, while on bars a forward lean shares the depth. The researchers think loading the front of the joint capsule this way, again and again, might strain it. That is their hypothesis: the study measured movement and muscle activity, not injuries or pain. In 15 experienced men who dipped to failure, tired reps got slower and shallower, not deeper.
Sources 1, 2, 3, 4
Where it hurts sorts the causesEmerging evidence
NHS inform calls rotator cuff related pain (subacromial pain) the most common reason for shoulder pain; it hurts at the front or outside of the shoulder and upper arm, especially lifting the arm or reaching behind you. The American Academy of Orthopaedic Surgeons (AAOS) lists pain at the front of the shoulder that is worse reaching backward, for a seatbelt or a coat, among the signs of biceps tendon pain, usually alongside rotator cuff problems; the bottom of a dip is the same backward reach, though that link is our reading.
Pain on top, at the end of the collarbone, is the AC joint. In people who press heavy and often it can be weightlifter's shoulder (distal clavicle osteolysis), a stress reaction at the end of the collarbone: 45 of 46 athletes in the first series lifted weights, and bench pressing was behind 49.1% of 483 published cases. A torn pec tendon happens almost only in men, usually lowering a heavy weight with the arm out and back: 63.2% of 664 injuries were in weight training, mostly on the bench press, and dips aren't a listed cause in the pooled data. It brings a tearing feeling, bruising, a changed armpit fold and weakness pushing.
Sources 5, 6, 7, 8, 9, 10, 11, 12
How often dips are blamed, and what has been reportedEmerging evidence
In an online survey of 1,387 recreational gym users, 732 reported training pain. Of those, 35% of the people who did bodyweight dips linked them to pain, against 21% for bench dips and 9% for dip machines; the shoulder was the commonest pain site overall, though the survey didn't split pain sites by exercise. It is a self-selected survey, so it can't give a risk per session.
Published injuries from dips are rare. The lab group found only two case reports of pec ruptures on bar dips (one with added weight), and there are single reports of a stress fracture at the top of the breastbone during wide-grip dips and a collarbone and rib fracture during triceps dips. These show what can happen, not how often.
Sources 4, 1, 13, 14, 15
What a scan shows, and when it mattersStrong evidence
Not at first, for an ache at the front or outside of the shoulder. Rotator cuff changes on scans are common whether or not they hurt, rising from 9.7% of people aged 20 and under to 62% from 80 (30 studies, 6,112 shoulders), and labral tears were read on 55% to 72% of magnetic resonance imaging (MRI) scans of painless shoulders in people aged 45 to 60. NHS inform says nerve symptoms from the neck usually don't need X-rays or MRI.
A scan matters after a fall or a shoulder that came out of place, which needs hospital treatment; for a suspected torn pec, which needs prompt imaging because early repair does better; and for pain on top of the shoulder in a lifter that isn't settling, where MRI shows swelling in the bone at the end of the collarbone in most cases (72.2%).
Sources 16, 17, 18, 19, 9, 7
How it usually goesStrong evidence
No study follows shoulder pain from dips. In general practice, only about half of new episodes of shoulder pain fully recovered within 6 months (16 cohort studies), and high pain at the start predicted a slower course; in 101 Dutch patients, 51% still had complaints, mostly coming and going, at 26 weeks and 41% at 12 to 18 months, though many of them considered themselves cured. These are general shoulder pain figures, not lifters'.
The NHS says shoulder pain can take 6 months or longer to recover, and NHS inform expects new pain to begin to settle within 6 weeks. Most weightlifter's shoulder settled with changed training (415 of 483 people). No one can promise a date.
Sources 20, 21, 22, 23, 7