Matteo Campagna
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While aiming, a movement of a fraction of a millimetre becomes centimetres of error on the target

3 studies · 15 archers measured

ForContextAgainst20142016201820202022202420262021, context, n = 152017, for, n = 52014, for
Each circle is a study: its position gives the year, its row whether it is for, against or context, its size how many participants it measured. Light circles are studies on other populations or without archers.

The arithmetic is geometric and it holds. The ten ring of an 80-centimetre face at 50 metres subtends 5.5 minutes of arc, and with a 70-centimetre arrow keeping the sight inside it means holding the bow steady to within about half a millimetre; an engineering study of bow tremor reaches the same order of magnitude from the other side, since a sight one metre away that moves by 1.74 millimetres sends the arrow 122 millimetres off at 70 metres. These are calculations, though, not measurements: no study in the bibliography has recorded in archers how far the sight moves at the moment of release and compared it with where the arrow lands. All we have in archers is the scale of the movement, and it shows where the proportion stops: in 15 national-level archers at 18 metres the aiming point moves by about 8 centimetres on the target in the last three tenths of a second before release, yet that range goes with the score in only two of the four conditions tested: the archers who move more while aiming do not always score less, and how much of that movement ends up in the arrow has not been measured.

Also phrased as: "a millimetre at the bow is a metre at the target"; "small movements while aiming, big errors on the target"; "it takes almost nothing to leave the ten"; "the error grows with distance"

In practice

Archers are told that while aiming it takes almost nothing, a movement too small to see, to send the arrow out of the gold, which is why a steady bow matters more than any correction.

Evidence

  • 2014
    For Model Published later

    A study of scores and arrow groups at two major international events in 2013; the passage that matters here is a calculation, not a measurement. The 10 ring of the 800 mm face subtends 5.5 minutes of arc at 50 m, and with a 0.7 m arrow keeping the sight inside the ten means holding the bow steady to within about ±0.5 mm. The archers in the study were not measured on this point.

    Analysis of scores and arrow grouping at major international archery competitions · James L Park, James E Larven

  • 2017
    For Model Published later

    An engineering study of bow tremor, with a model of the arms and accelerometer measurements on 5 subjects. Its introduction gives the figure that matters here: if the sight, 1 m away, moves by 1.74 mm because of tremor, at 70 m the arrow lands 122 mm away. It is a geometric proportion set out as a premise, not a result of the experiment.

    Suppression of tremor on bow by using dynamic vibration absorber · Yusuke Mizuno, Ikuma Ikeda, Nobuyuki Iwatuki

  • 2021
    Context Archers Published later

    15 male archers from Turkish national squads, a simulated indoor competition at 18 m, 30 arrows per trial: in the three tenths of a second before release the aiming point, tracked with a laser on the target, moves by 8.29 ± 1.91 cm in the control trial and 8.41 ± 2.02 cm with the placebo, while the centre of pressure travels 11.03 ± 4.00 and 11.86 ± 3.74 cm. The range of aiming-point movement goes with the score under placebo (r = −0.776) and in one of the two drug trials (r = −0.516), but not in the control trial or the other drug trial. It gives the real scale of movement while aiming, not the step from a millimetre at the bow to a centimetre on the target.

    Effects of beta-blockers on archery performance, body sway and aiming behaviour · Emin Ergen, Tahir Hazir, Mesut Celebi, Ayşe Kin-Isler, Serdar Aritan, Volkan Daghan Yaylıoglu, et al.

Status history

  1. 2014 Transferred The first figure comes from a study of scores at two major international events, and it is a piece of geometry: at 50 metres the ten ring subtends 5.5 minutes of arc, and with a 70-centimetre arrow staying inside it means holding the bow steady to within about half a millimetre. Nobody has measured this in archers: the claim rests on a calculation, so the status is transferred.
  2. 2017 Transferred An engineering study of bow tremor reaches the same order of magnitude starting from the sight: 1.74 millimetres of movement one metre away become 122 millimetres off at 70 metres. Two independent calculations agree, but they remain geometry and models, and the status does not change.
  3. 2021 Transferred The first measurement in archers arrives, of the scale of the movement rather than of the step from millimetres to centimetres. In 15 national-level archers at 18 metres the aiming point moves by about 8 centimetres on the target in the last three tenths of a second, and that range goes with the score in only two conditions out of four: the archers who move more while aiming do not always score less. The link between a millimetre at the bow and a centimetre on the target is still calculated, and the status stays transferred.

Related

Related articles

Research lines

Cite
APA

Campagna, M. (2026). While aiming, a movement of a fraction of a millimetre becomes centimetres of error on the target (Version 1). In Evidence Registry. Retrieved 16 October 2026, from https://matteocampagna.com/en/registry/technique/millimetres-at-aim-centimetres-on-target

BibTeX
@misc{campagna2026_miramillimetribersaglio,
  author = {Campagna, Matteo},
  title = {While aiming, a movement of a fraction of a millimetre becomes centimetres of error on the target},
  year = {2026},
  howpublished = {Evidence Registry, matteocampagna.com},
  url = {https://matteocampagna.com/en/registry/technique/millimetres-at-aim-centimetres-on-target},
  note = {Version 1; accessed 2026-10-16}
}

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