Anyone who has been shooting for a few years knows the ache at the bottom of the back after a long day on the shooting line, and sooner or later wonders whether the bow is to blame. In clubs the answer usually comes in two parts: archery puts no strain on the back, because the draw is done with the shoulders, and if the back hurts it is down to posture, not draw weight. Behind this there are two questions that can be measured. The first is how much load reaches the lower back with the bow you shoot, and whether it grows as you go up in pounds. The second concerns asymmetry: you always shoot from the same side, with one arm pushing and the other pulling, and it is natural to wonder whether over time the body, and the back in particular, takes on that shape.
On the first question there is a single research group, with estimates calculated by a model and light bows, and what it found is a wide margin below the thresholds used in ergonomics. On the second, the studies split by region of the body: the archer's arms and hands are asymmetric, while the trunk muscles and the spine, so far, are not. A survey of tenth-century skeletons acts as a cross-check, because on the bones too, what shooting leaves behind is harder to tell apart than one might imagine.
How common back pain is among archers
In most samples the shoulder is the site archers mention most often, and in the registry the claim that it is the most common site of overuse injury is reported. Right after it, in several samples, comes the back. In the 1971 Japanese survey of kyudo, 59 of 122 practitioners reported lower back complaints, just fewer than the 62 who reported them at the shoulder; among 239 archers in Florida the back accounted for 31.7% of those who had been injured, and at the European Youth Championships, among two hundred archers aged 13 to 20, the lower back was the second site of pain after the shoulder.
In competitive recurve archers the picture changes: among 62 German archers of national and European level the back accounted for 5.9% of overuse injuries, and among 58 Korean competitive archers, from middle school to company teams, for 6.9%. These figures cannot be added up or compared directly, because some studies count reported pain and others injuries, and they mix different ages and levels. What they do show is that back pain in archers is not an exception, especially in kyudo and among the young archers at the European Championships, and none of these counts says where it comes from. To get at that, you have to look at the load.
How the load on the lower back is estimated
The load on the lumbar spine of someone shooting is not measured directly: it is estimated. The only group to have done this with archers, an engineering group at a US university, fitted thirteen students from the university club, seven men and six women, with seventeen inertial sensors and fed the reconstructed posture into ergonomics software that calculates the forces between the fourth and fifth lumbar vertebrae. The thirteen were of mixed ability, four experts, four intermediates and five beginners, and they shot the club's barebow recurves of 20, 25 and 32 pounds at ten and fifteen yards.
Three papers came out of this sample between 2024 and 2025, each looking at a different moment of the shot: the draw, the instant before release and the release itself. For the registry they remain a single study, because the people are the same. The thresholds the authors compare their figures with come from occupational ergonomics: 3,400 newtons for compression, the safety limit recommended in that field for manual lifting, and 700 newtons for shear forces. They give the numbers a scale; they are not clinical thresholds and were not designed for sport.
How much draw weight loads the back
With the club bows the margin is wide. Depending on the paper and the condition, estimated compression runs from about 470 to about 890 newtons, between a seventh and just over a quarter of the 3,400 limit, and shear forces sit between 18 and 64 newtons against a limit of 700. The highest value, 891 newtons, comes from the men with the 32 pound bow at ten yards at the instant before release; at release, in the 2025 paper, the same men in the same condition are at 773. No combination comes close to the limit, which is why in the registry the claim that with bows up to 32 pounds the loads on the lower back stay below risk thresholds is reported.
Within that margin, draw weight matters less than you might expect. Going from 20 to 25 pounds does not clearly shift compression, and neither does raising the target. Going to 32 pounds raises it in the men, at ten yards from 581 to 773 newtons, while in the women it stays where it was, from 511 to 488. The standard deviations are wide, though: in the men, at ten yards, they exceed 260 newtons with both the 25 and the 32 pound bow, more than the 192 newtons that separate the 20 from the 32. So the load varies more from one person to the next than from one bow to the next.
Men, women and the position of the trunk
In the same sample the men load the lower back more than the women in every condition: by about 60 to 130 newtons with the 20 and 25 pound bows, and by more with the 32, when the gap widens because the men's compression rises and the women's does not. In the registry the claim that with the same bow, men and women load the lower back differently is reported, with one caveat: in the first paper compression is linked mainly to body mass, with a correlation of 0.62, and less to trunk flexion, with 0.40, and with thirteen people sex cannot be separated from body size, or from how demanding that bow is for each archer.
The way the women reach a lower load with the heavier bow is the most interesting part of the study. With the 32 pound bow they lean the trunk back by about 18 degrees, against 6 to 8 for the men, rotate it to the right and tend to lock the bow elbow in hyperextension, at around 9 degrees past straight against about 4 for the men. Across the whole sample, the further the trunk leans back the lower the calculated compression, and the link grows stronger with draw weight: 0.35 at 20 pounds, 0.39 at 25, 0.53 at 32.
The body angles that change with the heavier bow are gathered in a separate claim, with a heavier bow the angles of trunk, shoulder and elbow change, which is contested: in the women something changes, while in the men none of the comparisons between the three bows is significant. The bows were also tried in the same session and always from the lightest to the heaviest, so draw weight, order and fatigue cannot be separated, and with six or seven people per group a null result does not rule out an effect.
This invites reading a backward-leaning trunk as a way of taking load off the back. The model, however, calculates compression at one vertebra and nothing else: it says nothing about what happens to the locked elbow or the rotated trunk. The authors themselves read those postures as adaptations to the heavier bow, and among the recommendations they give are neutral shoulders and elbows, a straight spine and a bow suited to the person shooting it. Nobody has tried changing an archer's posture to see what happens to the load, let alone to pain.
Where these measurements stop
The forces are calculated rather than measured, over a few shots per condition, and there is one sample. Above all, the bows are far from competition ones, and the authors of the second paper say so: their values sit below the limit, but a competition bow can reach 60 pounds. In the largest international samples the recurve average sits above forty pounds, 42.9 at the 2012 European Outdoor Championships and 46.8 at a 2025 World Cup stage, although the typical range at the top remains a contested question. Nobody has estimated lumbar compression with a competition bow, across a whole session or after many arrows, and nobody has set the calculated load beside the pain reported by the same archers.
One figure on lower back pain in high-level archers that can be set beside these estimates comes from a pre-season screening: fifteen young elite Israeli archers, aged 17 on average and training at least seven three-hour sessions a week, none of whom reported low back pain, while two of the fifteen had pain in the thoracic region. It fits with the margin found in the laboratory, but it is a small group, looked at in a single moment.
Asymmetry of the action and asymmetry of the body
The second question starts from a fact nobody disputes: shooting loads the two sides of the body differently. Electromyography on both arms of nine recreational archers shows that during the draw the string arm uses more latissimus dorsi and biceps, and the bow arm more lateral deltoid and triceps; in five Russian elite recurve archers, measured on the trunk as well, the erector spinae works harder on the string side, while latissimus dorsi, pectoralis major and upper trapezius work harder on the bow side. Whether the string side works harder overall, however, is a contested claim, because the answer changes with the muscle and with the phase of the shot.
An asymmetric load does not necessarily mean an asymmetric body, and here the studies split by region. In the arms and hands asymmetry is found. In thirteen young registered Turkish archers, all right-handed, the drawing side is stronger, with small differences in the large shoulder and elbow movements and very marked ones in the finger pinches; the same side has tighter external shoulder rotators and a shoulder blade that slides further out to the side. In twenty young Malaysian archers the grip gap between the two hands is 6 kilograms, against 1.3 in peers who do no sport, but that gap was never tested and the archers were heavier.
In the trunk muscles and the spine, on the other hand, asymmetry has not turned up so far. In the fifteen young elite Israeli archers ultrasound found the same thickness of the deep muscles, multifidus, transversus abdominis and internal oblique, on the dominant and non-dominant sides, at rest and during contraction. In the thirteen Turkish archers the endurance of the lateral trunk muscles was the same on the right and the left; the same study finds only small differences in trunk rotation mobility and in posture, without any comparison with people who do not shoot. And among the thirty kyudo practitioners with the most marked complaints, examined and X-rayed in 1971, none had scoliosis, either cervical or lumbar, despite the asymmetric shooting posture.
In the registry the claim that the asymmetric shooting action creates muscle asymmetries is contested: the Turkish study of the arms supports it, the studies of the trunk and spine go against it, and the limits are shared by almost all of them. Nobody has followed the same archers over time, and almost all compare the right side with the left in right-handed people, who have a difference between the hands even without a bow. Two before-and-after comparisons point the same way. In thirty-six beginners, according to a systematic review, twelve weeks of shooting improved the precision of an arm movement by similar amounts on both sides, a measure of control rather than muscle, and the difference between the sides stayed where it started. In 34 sedentary young men, twelve weeks of shooting increased grip by similar amounts in both hands, without widening the gap.
A separate figure concerns how developed the trunk is, rather than how symmetric. Using magnetic resonance imaging on 352 Japanese athletes of national and international level, 88 of them archers, adult archers had a smaller psoas, erector spinae and lateral abdominals than wrestlers of the same height, and women archers smaller lateral abdominals than table tennis players and gymnasts. For the registry, archery does not develop the trunk muscles as other sports do is a reported claim, resting on a single cross-sectional study, and in the same study the young athletes, archers included, still had larger cross-sections than peers who do no sport, in a comparison made with values published elsewhere.
What is left on the bones
If years of shooting left a recognisable mark, the skeleton is where you would expect to find it. The only study that has looked comes from anthropology: a Hungarian group examined by eye the arm and shoulder bones of 81 individuals from a tenth-century cemetery, 49 buried with a bow, arrows or quiver and 32 adult men buried without weapons. In the probable archers, enlarged attachments of the deltoid, pectoralis major, latissimus dorsi, biceps and brachialis are common, but the sites are largely the same in the men buried without weapons, and the authors conclude that comparing the two groups is not enough to recognise who shot.
The same cemetery provides a cross-check on asymmetry. Where the biceps attachment was asymmetric, in those buried with a bow it was on the right 11 times out of 17, while in the men buried without weapons it was 8 times out of 9: the probable archers were no more lopsided to the right than the others. These are visual assessments, without statistical tests, of people who may or may not have shot, using the bow of mounted archers a thousand years ago. This is why in the registry the claim that muscle-load marks on bones are not enough to identify an archer is transferred: it rests on a population the registry does not count as measured archers, and it says nothing about what today's recurve leaves on the bones.
What I take from this for the shooting line
These studies describe group averages and do not say which draw weight suits a particular back. With that limit in mind, I take three things from them.
The first concerns draw weight. With bows up to 32 pounds the estimated lumbar load is a fraction of the limit used in ergonomics, and it does not move between 20 and 25 pounds; besides draw weight, body mass and the position of the trunk played a part. There are no estimates for competition draw weights, so I would not extend that margin to a bow of forty pounds or more. When going up in pounds, though, you can look at what changes in the body: a side-on video at full draw, before and after the change of bow, shows whether the trunk leans back or forward more than before, which is what happened to the women in the sample with the 32 pound bow. I discuss the link between pounds and results in the article on draw weight and your score.
The second concerns asymmetry. The measurements find it in the arms and hands, where the different work of the two sides would lead you to expect it, and not in the trunk muscles or the spine. Whether compensating exercises in the gym reduce asymmetry or back pain has not been tested; there is only one comparison, made at a single point in time, in which archers who shoot from both sides did not show the shoulder asymmetries of those who shoot from one, and the claim that training both sides reduces asymmetries remains reported. So if you work on the trunk in the gym, I would not do it to correct an asymmetry that the studies have not found in the trunk muscles.
The third concerns pain. The counts say back pain is common among archers, especially young ones, and the laboratory estimates say that with light bows the calculated load stays far below the limit. The two do not rule each other out, because the model calculated a few rested shots rather than hours of training, and pain can have causes that the load on one vertebra does not capture. Lower back pain that does not settle within a few days, that returns at every session or that forces you to change the shot should be taken to a doctor or a physiotherapist, because finding its cause is the job of an examination, not of a statistic. I look at how injuries are spread across the body in the article on injuries in archery.