Who gets itEmerging evidence
We found no study that measured upper back pain in riders on its own. In a 1995 survey of 518 recreational riders, neck complaints were the commonest (48.8%), and women had twice the odds of shoulder complaints; a review lists the neck and shoulders among riders' commonest problems not caused by crashes.
Upper back pain is common in the general population (between 3.5% and 34.8% of people in a year, across studies) and has been studied far less than neck and low back pain. In 71 road riders, body position on the bike didn't differ between riders with and without upper body pain.
Sources 1, 2, 3, 4
Why the upper back and shoulders work hard on the bikeEmerging evidence
Your arms carry part of your weight on the bars and steady your trunk, and your neck and upper back hold your head up to see the road. In a lab study of 8 men, lower bars didn't change the upper back's curve, but with racing bars the bending load at the base of the neck was three times that of sitting upright; and in 26 riders, the further they leaned forward, the more they tipped the head back.
When reach changed, 12 riders took it up mainly at the shoulders and elbows rather than the spine, and a saddle tilted 10 degrees nose-down made the muscles that straighten the elbows work about 23% harder, because you slide forward onto your arms. Loads through the arms rose with power and were higher standing than seated, and arm and trunk muscles worked much harder above about 500 watts. Bars about as wide as the shoulders lowered arm muscle activity in 10 women, and stock bars are often wider than women's shoulders. Across 12 studies, the upper back tended to round more the longer people pedalled.
Our reading: an ache on the bike looks like muscle fatigue from holding part of your weight and your head for a long time, made worse by a long, low reach, a nose-down saddle, wide bars and hard or standing efforts. These are small lab studies in healthy riders, and no study has tested this as a cause of pain.
Sources 5, 6, 7, 8, 9, 10, 11
It isn't bad postureEmerging evidence
Riders' upper backs are often more rounded when they stand (48 degrees against 43 in non-riders in one study, and more than half of the elite and masters riders in another), but on the bike the upper back was less rounded than when standing, and the authors concluded that the standing roundness wasn't directly related to the riding position. Upper back roundness didn't differ between people with and without shoulder pain, and reviews of low back pain find no agreement that posture causes it.
Sources 12, 13, 14, 15
After a crashStrong evidence
Arm and shoulder injuries are about half of all injuries in competitive road cycling, and in one hospital's records of people hurt on bicycles, 24% had injured an arm or shoulder. In 157 riders with shoulder injuries at one hospital, 84% came from a direct blow to the shoulder: broken collarbones were 32%, acromioclavicular (AC) joint dislocations 22%, rotator cuff tears 22% and upper arm fractures 8%, and half were treated without surgery. In a survey of 140 professional and amateur riders, 13.5% had broken a collarbone riding, more often with more years and hours of riding.
The NHS says most people recover from a broken collarbone in 6 to 8 weeks, with a sling for 2 to 3 weeks and no lifting or sport while it heals, and to ask your doctor when you can go back to sport. Elite road riders with a single broken collarbone were back racing after an average of 57 days, most after surgery, and all 25 riders in a series with plate-fixed fractures returned to cycling, but these riders had medical teams, so their times aren't a target for anyone else. Broken or bruised ribs usually heal by themselves within 2 to 6 weeks, and a dislocated shoulder usually takes 6 to 12 weeks, with up to 16 weeks before some sports.
Sources 16, 17, 18, 19, 20, 21, 22, 23, 24
When a scan or test helpsStrong evidence
Without warning signs, an upper back or shoulder ache on the bike doesn't need a scan. After a crash, a suspected broken collarbone needs an X-ray, ribs often don't, and a dislocated shoulder is usually X-rayed. Chest pain, or pain that comes on with effort, is checked with an electrocardiogram (ECG), a recording of the heart's electrical activity, and blood tests, not a back scan.
Sources 20, 23, 24, 25, 26
How it usually goesEmerging evidence
No study has followed riders' upper back or shoulder pain. The NHS says you usually need about 2 weeks of looking after shoulder pain before it starts to ease, and that it can take 6 months or longer to recover. In adults, new mid-back pain is uncommon and its course has barely been studied, and in a trial of upper back pain every group improved with time. No one can promise a date.
Sources 27, 28, 29