Anthropometry and setup: draw length, arms, bow size

Of all the measurements that concern an archer's body, the one that decides the setup is draw length. Arrow length follows from it, and so do the spine you need and the draw weight you actually pull, which matches the figure printed on the limbs only if you draw close to the maker's reference length. The other measurements, such as arm length, height and the proportions of the chest, reach the setup only through draw length, and the studies that have set them against score do not agree: in one group of young recurve archers and one of university club archers long arms go with a few extra points, while among archers who have already been selected the link disappears.

So the article works in two stages. The first runs from draw length to the choices that depend on it: draw weight, arrow length, spine and bow length. The second deals with a question many archers ask when they look at a podium, whether a particular build helps you shoot better, and closes with the differences between men and women and with the setup mistakes beginners make most often. Tuning proper has an article of its own.

Draw length, the measurement to start from

Draw length is the distance at full draw between the bottom of the nock groove and the pressure point on the grip, to which the manufacturers' convention adds a fixed allowance. In practice it is how far you draw the bow when your posture is sound and your anchor is in place. It depends on wingspan and shoulder width, but also on where you anchor and how the draw elbow lines up behind the arrow, so two archers of the same height can have different draw lengths, and the same archer can see theirs change over the first months as the technique settles.

Wingspan, measured from fingertip to fingertip, gives you an idea of draw length before you have shot an arrow, but it remains an estimate. The draw length that counts is taken on the bow, with a marked arrow and ideally with an instructor watching, once the shot is stable: a draw length taken with the bow shoulder raised or an uncertain anchor records that fault, not your proportions.

There is also a basic difference between divisions. In recurve, barebow and traditional bows the draw length belongs to the archer and the bow simply follows it: the further you draw, the more weight you pull and the longer the arrow has to be. On a compound the draw length is set on the cam or the module, and the wall fixes the point where the draw stops, so the bow is fitted to the archer, and a badly set module shows up mainly in the anchor and the posture. What follows is mainly about the first case.

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The draw weight you pull at your draw length

The figure printed on the limbs holds at a reference draw length, and an archer who draws further or less far pulls a different weight. Two studies on archers have measured this and on paper they seem to contradict each other, so in the registry the claim that the draw weight marked on the bow differs from what the archer actually pulls at their own draw length is contested; read together, though, they describe the same rule. In 49 university beginners, with the marked figure referred to 26 inches, the women pulled 21.24 lb against the 26.18 marked and the men 30.55 against 33.52, and in the women the marked figure said almost nothing about the actual draw weight (r 0.039), in the men a good deal more (r 0.851). In six Japanese university archers drawing between 27.5 and 29 inches, that is around the reference, the measured draw weight was 36.5 lb against the 36 stated, and a machine test from 2025 with 52 lb limbs at 28 inches gave 231 newtons, about 52 lb.

The Japanese study also shows that the reference varies from one maker to another: one brand measured at 28 inches from the back of the bow, the other at 26 inches from the pivot point of the grip, and the two conventions match only because the pivot and the back are about two inches apart. For the setup the consequence is practical: the draw weight that spine selection and training load should start from is the one you pull at your own draw length, and it is better measured with a bow scale than read off the limbs, all the more so if you draw well away from the reference. Choosing it is covered in a dedicated article.

Build seems to play a part as well. In 33 Indian archers of national and international level, shooting bows from 26 to 60 lb, draw weight rose in bodies that were heavier for their height, with a correlation of -0.379 against a robusticity index that falls as the body gets fuller, and it rose with the hand index too (r = 0.420). In the registry the claim that archers with a sturdier build shoot heavier draw weights is reported, with three caveats: the sample mixes recurve and compound archers without separating them, many indices are crossed with draw weight, and an association measured once does not say whether the build allows more pounds or the pounds build the body. For anyone tempted to copy a training partner's draw weight, a simpler argument is enough anyway: the other archer's strength differs from yours and, if they draw to a different length, the same bow gives them a different weight.

Arrow length

Arrows are cut to draw length with a margin, because at full draw the point must never come back behind the rest: an arrow that slips off the rest during the draw can strike the hand or the riser on release. On a recurve with a clicker the margin also depends on the clicker, which has to drop off the point at the right place in the draw, so the length is decided with the clicker fitted and set. An arrow longer than it needs to be, on the other hand, is heavier, and therefore slower, and it behaves like a weaker shaft.

On arrow length as such there is a single study that sets it against score. Thirty-nine international-level recurve archers shot ten arrows each at 70 metres on a force platform, and of all the variables collected, the score of each arrow was predicted by clicker reaction time, draw weight and maximum sway speed, which together account for 42% of the variation; arrow length did not enter the model. In the registry the claim that one study of elite archers found no link between arrow length and score is reported, and it has to be read with its limits. Arrow length was reported by the archers and varied little between them, the published mean of 644.4 mm is short for that level and leaves a doubt about the units, and above all arrow length is not a free choice, because it depends on each archer's draw length. The result says that among elite archers arrow length does not explain differences in score, not that lengthening or shortening the arrow makes no difference for the same archer: changing it changes the spine.

From draw length to spine

Spine is the stiffness of the shaft, and the rule behind the manufacturers' charts is that it has to be matched to draw weight and arrow length: more weight and more length call for a stiffer shaft. In the registry the claim that arrow spine has to be matched to draw weight and arrow length is reported, because every model that has examined it reaches the rule, each by a different route, while the groups of archers shooting a suitable and an unsuitable spine have not yet been compared. The models do give the order of magnitude. In a recurve model calibrated on bench measurements, lengthening the shaft from 705 to 715 mm brings the draw weight at which the arrow stays tuned from 164.5 down to 160 newtons, so ten millimetres of arrow are worth four and a half newtons; moving to the next spine calls for about eleven, and since a recurve can typically be adjusted within about 10% of its nominal weight, only one or two spines can be tuned well at a given draw length. A model from 2025 built on competition shafts produces charts in half-inch steps and finds that the recommended spine already changes between adjacent lengths.

Two consequences follow for anyone setting up a bow. The first is that draw length enters the spine twice, because it decides both arrow length and actual draw weight: on the same bow, the archer who draws further pulls more weight and shoots longer arrows, and both push the choice towards a stiffer shaft. The second is that the charts should be read with the draw weight measured at your draw length, not the one printed on the limbs. How spine shows up in the arrow's flight is explained in the article on the archer's paradox.

Bow length

On recurve and traditional bows, bow length follows draw length: an archer with a long draw needs a longer bow, which means a longer riser or longer limbs. The reason is mechanical: a bow that is short for your draw length works close to its limit, where a bow without cams can stack in the last few centimetres, and the string makes a sharper angle across the fingers, which pinches them and spoils the release. These are rules of practice and of the manufacturers, not findings from studies. On a compound the question is framed differently, because the draw length is set on the cam and the length of the bow is chosen for other reasons.

Body measurements and score

So far the body's measurements have served to size the equipment. Many archers also wonder whether a particular build brings points, and on that the registry holds five claims, all resting on cross-sectional studies of small groups.

Long arms

Arms are the most studied case, and the studies on archers split mainly by level. In one youth group and one club group the link shows up: in twelve young Malaysian recurve archers arm span is the measure most closely tied to score (rho 0.822), and in twenty-three university club archers longer arms go with a few more points at 18 metres, 6.4% of the variance. Among national and international archers, by contrast, the link disappears: in thirty-three Indian archers none of the eleven body measures is related to score. In 2025, moreover, two very different samples, forty-five adult Turkish traditional archers and seventeen middle-school beginners, found nothing either.

That is why in the registry the claim that archers with longer arms are more accurate is contested, and the split has a plausible reading. In groups that mix ages and levels, long arms travel with height, age and experience, and no study has pulled them apart, so much so that in the twelve Malaysians height correlated with score almost as closely as span did; the hypothesis is that among archers who have already been selected the measure stops telling them apart.

Draw length

Draw length, which is the measurement that matters on the bow, has a single study setting it against score, in 62 male national-level recurve archers in Indonesia, and the link it finds is mostly indirect. Draw length has a direct effect on score of 0.15, or 2.25% of the variance, and a larger one through assessed technique, about 0.23, because archers with a longer draw tend to have technique judged better and those with better technique score more. The claim that in archers a longer draw length goes with higher scores is therefore reported, on data presented unclearly and without separating draw length from height, so a long draw in absolute terms may simply mean a taller archer.

The profile of the high-level archer

The ideal archer is often said to have long arms and a narrow chest, and the profile does turn up. In the 33 Indian archers of national and international level, arm span exceeds height in every one of them, with a mean index of 104.8, and the chest is narrow in all of them; in a small study from 1987, two world-class archers had an arm span of 180 centimetres against 172-177 in three less experienced archers of similar height. In the same Indian sample, however, none of the eleven proportions is linked to score, which follows only draw weight, and in 1981 six Japanese university archers had a narrower chest, not a broader one, than their country's Olympic candidates. The claim that high-level archers have long arms relative to their height and a narrow chest is contested: the profile exists, but these are descriptions of tiny groups with no comparison against people who do not shoot, and nobody has shown that the build helps anyone shoot better.

Height and level

On height, the studies comparing archers of different levels split down the middle. In favour there are 100 Indian recurve archers in whom the 50 of higher level are 11 centimetres taller and 8 kilograms heavier than the beginners, with no statistical test at all and in a journal with questionable editorial standards, and the twelve young Malaysians, where the best are about 12 centimetres taller but not heavier. Against there are 20 young Swedes grouped by level by their coaches, with no difference in height or weight, and the 33 elite Indians, in whom height and weight are not linked to score. The sticking point is age: where groups mix adolescents of different ages, a few extra centimetres can be growth rather than selection, and in elite Japanese male archers height and weight settle only at around 16. The claim that higher-level archers are taller and heavier than beginners is contested, and the part about height holds up a little better than the part about weight.

Recurve, compound and traditional bows

One last question concerns the division, that is whether recurve archers are built differently from compound archers. There are two pieces of data, both small. At the 2014 Indian inter-university championships, among 160 archers aged 18 to 25, the recurve archers averaged 176.7 centimetres and 68.2 kilograms, against 160.5 centimetres and 61.7 kilograms for those shooting the Indian traditional bow and 163.3 centimetres and 58.4 kilograms for the compound archers; the author, however, runs no statistical test, does not say how many were men and how many women, and the journal has questionable editorial standards. In 2020 seven elite Indian archers, four compound and three recurve, point the same way, 166 against 172 centimetres, but with no significant differences and in a sample too small to find them. The claim that recurve archers are on average taller and heavier than compound or Indian traditional archers is therefore contested, more for lack of data than because the studies conflict, and neither says whether taller people choose the recurve or whether teams and selection play a part.

Taken together, these studies do not show that body measurements decide score among archers who have already been selected, and where a link appears there is nearly always another explanation close at hand, such as age or level mixed within the same group. Strength is in the same position: the claim that arm strength is linked to shooting accuracy is contested, because the studies contradict one another and often measure different qualities under the same name. Body measurements remain essential for sizing the equipment, but as a way of identifying talent they lack solid support.

Men and women

The comparison between men and women is functional anthropometry before it is setup, and it is mostly about strength. In 1967, among 49 beginner university students, the men's maximum drawing strength was almost double the women's, 69.5 against 40.1 lb, and in 2015, among 160 children aged ten to twelve on an archery introduction programme, the boys outdid the girls in every strength test despite being the same height. The claim that among people who shoot, men have far greater drawing strength than women is reported, since the two samples are of beginners and children and the second gives only means. For the setup, though, the most useful figure is draw weight: in the 1967 group the men were pulling 30.6 lb on average and the women 21.2 lb, which, working from the means, is 44% and 53% of their own maximum strength, so proportionally it was the women who were shooting heavier. They were also the ones pulling furthest from the marked figure, almost five pounds below it, and it was in the women that the marked figure said almost nothing about the actual draw weight.

The strength gap is not uniform either. In forty-five Turkish traditional archers aged 20 to 35 it was huge in the back, 150 against 73 kilograms, and smaller in grip, 39 against 31, while the women were quicker on the nine-hole peg test of fine dexterity with both hands and more flexible on the sit and reach, 29.9 against 24.9 centimetres, and one-leg balance was the same. In the same group shoulder width and forearm length did not differ between the sexes, while whole-arm length did, 76.08 against 72.08 centimetres. The claim that between male and female archers the strength gap is large, while on flexibility and dexterity the advantage reverses is reported: for strength there is more than one piece of data, the reversal on flexibility and dexterity rests on a single study, and none says how much of these differences reaches the score at equal draw weight. Other aspects, from biomechanics to the menstrual cycle, are in the article on women and archery.

Common mistakes in the initial setup

Beginners tend to slip up on the setup in the same places, and almost every mistake comes from a draw length that was measured badly or ignored.

• Mistake 01

  Copying someone else's setup

  Taking a training partner's bow, arrows and draw weight because they work for them. If their draw length differs from yours, the same bow gives you a different weight, their arrows are not your length and the spine is no longer matched.

• Mistake 02

  Measuring draw length carelessly

  A draw length taken with sloppy posture or an uncertain anchor records the fault, not the measurement. It should be taken with correct technique, ideally with an instructor, and taken again after the first few months, once the shot has settled.

• Mistake 03

  Arrows that are too short

  Arrows get cut right at the limit of draw length to gain a little speed. If the point comes back behind the rest at full draw, the arrow can fall off the rest and strike the hand: the margin has to be kept, and on a recurve it must leave the clicker room to work.

• Mistake 04

  Reading draw weight off the limbs

  Choosing spine and training load from the printed figure. That figure holds at the maker's reference draw length, and at your draw length the weight can be a few pounds different: measure it with a bow scale.

• Mistake 05

  Buying the final kit too early

  Buying competition arrows before draw length and technique are stable. In the first months draw length can change, and with it the right arrow length and spine: a basic setup sized to today's measurements, redone once the shot has settled, is the better choice.

@misc{campagna2026_antropometriasetup,
  author = {Campagna, Matteo},
  title = {Anthropometry and setup: draw length, arms, bow size},
  year = {2026},
  howpublished = {matteocampagna.com},
  url = {https://matteocampagna.com/en/articoli/anthropometry-and-setup},
  note = {accessed 2026-10-16}
}