Compound: what research says about shooting with cams

Who is in the compound studies

Thirty-three studies in the registry concern the compound, and twenty-one claims deal with it closely. Research, though, has looked at the bow more than at the people who shoot it: thirteen of these papers have no archer in them at all, because they are mathematical models, shooting machines and bows drawn in a laboratory with a winch, and much of the mechanics comes from a single author. The samples of archers are small and almost always mixed: in the direct comparisons, the compound archers placed beside recurve archers usually number between four and eighteen, and only an Indian university championship counts 42.

Here I bring together what they found and mark where the data run out. How to choose between the disciplines is covered in the article on barebow, Olympic recurve and compound.

What the bow does

Speed is the most repeated finding. Measured in the laboratory, four compounds launch the arrow at between 70 and 82 metres per second, while the two recurves sit between 57 and 65, and the competition data of 61 archers at the Shanghai stage of the 2025 World Cup also show that compound arrows leave the bow much faster, about 89 against 66 metres per second once the units are read as feet. Nobody has made the comparison with the same draw weight and the same arrow. At the same event the compound archers drew an average of 56.6 pounds against 46.8, with shorter arrows, 71.1 centimetres against 75.6.

The speed comes from the shape of the force curve. Three bows measured one at a time store 73.7, 96.5 and 92.8 joules, and the 2015 bow sheds about 65% of the force at full draw, so about a third of it is held while aiming; a 2017 model shows, however, that let-off is a design choice, ranging from under 50 to about 80%. The figure that at the same peak force a compound stores 75% more energy and, for the same energy, is held with 2.3 times less force comes from a calculation in which the recurves exist only on paper. Finally, on two bows the force is a little higher on the draw than on the let-down.

Where the nocking point travels also matters. On a single cam the path would stray from a straight line by 21.8 millimetres without correction, and it stays within 1.5 once the manufacturer has corrected the cam grooves. These are calculations checked on a few bows, and nobody has yet put the groups of a corrected bow beside those of an uncorrected one.

The arrow leaves almost straight

This is where the sharpest difference from the recurve comes from. In 2011, on a single-cam bow mounted on a shooting machine with a release aid, the arrow flexes by only a few millimetres, against the 10 to 15 the author expects from a recurve, and leaves the string almost aligned, 17 milliseconds after the release. How much the release aid accounts for was measured in an experiment on a recurve mounted on a robot: the arrow oscillates by 1.22 millimetres with a mechanical release and by 6.86 when shot by two national-level archers.

Two consequences follow, both from the same 2011 paper. The first concerns spine: three shaft sizes, 470, 420 and 380, all produce small, similar groups within a 40-millimetre circle at 35 metres, so with a compound and a release aid spine matters less; only arrows stiffer than the recommended one were tested, though, never weaker ones. The second concerns the rest: in the model, moving it 2 millimetres sideways shifts the angle of attack from 0.1 to -0.2 degrees and leaves the centre of mass on almost the same path, so its position matters little as long as the fletchings pass cleanly. Nobody, however, has moved the rest on a real bow and looked at the groups. On cams, finally, a conference abstract finds that after physical effort fifteen experienced archers lose the same amount of accuracy with a single cam and with a twin cam.

Who shoots compound

Among young competitive archers the compound remains a minority: 27.5% of the 200 archers at the European Youth Championships and 39.0% of 251 Turkish competitors aged 17 to 20. Whether compound archers are shorter and lighter than recurve archers is contested: at an Indian university championship the gap is 13 centimetres, with no statistical test and in a questionable venue, and in seven elite archers it is not significant.

On the body the data are scarce. In eleven Russian archers the balance quality index in the two seconds before the release is 69.9% in the compound archers and 40.3% in the recurve archers, but the paper runs no test between the two groups, and the claim that compound archers hold their balance better remains an isolated finding. The 2025 Taiwanese comparison says the body does not move in quite the same way with the two bows: of fourteen measures, seven stay the same and seven differ. Half a second before the release the compound archer's centre of pressure travels further, 61.6 millimetres against 51.9, while a tenth of a second afterwards it sways less forwards and backwards, 3.2 against 5.4. In the same archers the recurve group has stronger horizontal abductors of the shoulder, 19.0 and 19.1 kgf against 15.4 on the two sides, but four comparisons out of eight show no difference, and the recurve group included more men.

What happens to the score

That compound archers score higher, even with each shooting their own distance, is currently reported: in the 37 Taiwanese pre-elite archers the average per arrow is 9.1 at 50 metres against 8.3 at 70, and the only contrary result, in twenty young Swedes, includes just five compound archers. The comparison does not separate the bow from the target, because the compound archer aims at an 8-centimetre ten on an 80-centimetre face and the recurve archer at a 12.2-centimetre ten on a 122-centimetre face. There is only one direct comparison of groups, of eleven compound and eight recurve archers at 18 metres, and it says the compound groups more tightly without giving the values.

At the top, scores approach the maximum. At the first World Cup stage of 2013 sixteen compound men scored 350 or more out of 360 in the first 36 arrows. Proportionally, though, the ranking is no more compressed than the recurve one: a ranking place is worth about 0.7 points out of 720 in compound and 1.4 out of 1440 in recurve, 0.1% of the maximum in both cases. Indoors, seven elite Indian archers, four compound and three recurve, average around 9.5 points per arrow, but the threshold of nine and a half points at 18 metres remains contested, partly because the two bows are never separated in the data. The largest counts behind the claim that the ten is not guaranteed come from recurve or do not distinguish the divisions.

Where the research is thin

We know the mechanics of the compound better than the people who shoot it. The measurements on the equipment cover one bow at a time, and the comparisons with the recurve mix discipline, level and target. Three things are missing above all: the first is samples of compound archers alone, split by level and by sex; the second is a test on the target of what the models predict about spine, rest and nocking point; the third is the shot specific to the compound, meaning how the archer reaches the release with a release aid, which these studies touch on only in passing, in a few measures of the wrist or of the forearm muscles. For how the arrow behaves in flight there is the article on the archer's paradox and arrow spine.

@misc{campagna2026_enresearchpopulationscompound,
  author = {Campagna, Matteo},
  title = {Compound: what research says about shooting with cams},
  year = {2026},
  howpublished = {Research, matteocampagna.com},
  url = {https://matteocampagna.com/en/research/populations/compound},
  note = {accessed 2026-10-16}
}