Small differences in launch speed account for much of the vertical spread

The summary today

The mechanics are clear and the measurements agree, but nearly all of those measurements come from machines. At seventy metres, with a compound launching at 74.5 metres per second, one metre per second more launch speed raises the point of impact by about thirteen centimetres, almost twice what a one-metre error in distance or twenty per cent more aerodynamic drag would do. With a slower arrow, at sixty metres per second, a model for the traditional bow gives more than twenty centimetres per metre per second. High-speed footage shows that the vertical offset at the target matches the vertical component of launch speed multiplied by the time of flight: the agreement is good when a robot is shooting, weaker with the one archer filmed, where the variability of horizontal speed also weighs in. In fifty-nine arrows of the same model shot by machine, mass and mean spine account for 46.7 per cent of the vertical spread and less than a fifth of the horizontal one, and the same study cuts the size of the effect down: the ballistic calculation predicted over fourteen centimetres of vertical range, while the measurement gave 8.8. In archers the speed varies very little, one or two kilometres per hour from one arrow to the next, and across seven archers from the German national squads neither mean speed nor its consistency entered the model of the score. The direction is solid, the size needs revising and the link has never been measured in a group of archers: that is why the status is "Reported".

Also phrased as: "arrow speed moves the impact up or down"; "why arrows land high or low"; "vertical spread and launch speed"; "a steady draw length holds the height of impact"; "heavier arrows land lower"

Evidence

• 1933
  Context Model Published later

  A theoretical model of the trajectory, with air drag proportional to the square of speed and a bow efficiency taken as 0.60: for a 300-grain arrow launched at 180 feet per second, about 55 m/s, a difference of 5 feet per second at launch, about 1.5 m/s, which the author considers possible from one shot to the next, shifts the maximum range by 26 feet, or 4 per cent. It concerns range at around 45 degrees, not the height of impact on a flat trajectory.

  The aerodynamics of an arrow · George Judson Higgins

• 2012
  Context Archers Published later

  Seven archers from the German junior and senior national squads, thirty arrows at eighteen metres indoors, timings and speeds picked up by a microphone and the score fed into a stepwise regression: neither mean arrow speed nor its consistency enters the model, and the coefficient of variation in speed sits between 0.23 and 0.58 per cent. It does not contradict the mechanics; it warns that at this level speed is not what separates one archer from another. The speeds are reported in an implausible unit, between 186 and 231, and can only be read as ratios.

  Evaluation of arrow release in highly skilled archers using an acoustic measurement system · Mario Heller

• 2012
  Context Archers Published later

  Three recurve archers from the Malaysian national squad, measured arrow by arrow at seventy metres with radar and electromyography: mean launch speeds are 197.9 ± 1.0, 219.4 ± 1.8 and 220.3 ± 0.9 kilometres per hour, that is one or two kilometres per hour of variation within the same archer. This is the real size of the small differences the claim is about, in three archers and without the link to the point of impact.

  Influence of Muscle Activity on Shooting Performance in Archery: Preliminary Findings · Edin Suwarganda, Ruhil Razali, Barry Wilson, Ahmad Pharmy

• 2015
  For Equipment tests Published later

  A compound bow and its arrows, launch speed 74.5 metres per second, measured in the laboratory and in the field with a shooting machine and compared with a ballistic calculation validated on those same measurements: at seventy metres one metre per second more speed raises the point of impact by about thirteen centimetres, while a one-metre error in distance is worth about seven and twenty per cent more aerodynamic drag another seven. No archers, a single set-up, and the work is a preprint.

  Applications of Physics to Archery · H. O. Meyer

• 2019
  Context Equipment tests Published later

  A prototype shooting robot with a static analysis of the drawn bow: without a clicker the draw length varies from shot to shot, and the authors put the up-and-down spread down to that variation together with the nocking point. An observation with no figures, in a conference paper.

  Statics Investigation about Archery Robot in Drawing a Bow · Takuto Nakamura, Yogo Takada, Hitoshi Watanabe

• 2019
  For Model Published later

  A ballistic calculation at constant bow energy, 45 J, with a 23.361 g reference arrow and no friction or shaft flexing: the heavier arrow leaves more slowly, and at seventy metres half a grain more lowers the impact by 0.87 cm, half a grain less raises it by 0.94 cm. The weight ranges measured on twenty-six dozen X10s shift the impact by about 3.5 cm with a difference of 1.96 grains and by over 20 cm with the 11.64 grains of spine 380. It is a model from the same group that in 2025 found the ballistic calculation more generous than the measurement, and it contains no measurement of speed or impact.

  A study of the influence of arrow mass on ballistics · A. Kuch, J.-F. Debril, J.-M. Tizzoni, P. Laguillaumie, T. Monnet

• 2020
  Context Equipment tests Published later

  A shooting machine with a recurve bow at seventy metres: with the release triggered by the clicker, that is with the draw length always the same, the vertical spread is smaller than without. The comparison is shown as a graph and the authors report no standard deviations, so it reads as a direction rather than a measurement. On the article's main result, the selection of arrows, it should be said that it cannot come out otherwise: the abnormal ones are identified with a circle of twice the standard deviation computed on the four good arrows of the same group, and a circle built that way contains them as a property of the operation. The two flawed ones, moreover, were known beforehand, and one was missing a vane. The standard deviation's value is given in no units.

  Development of an Archery Robot for the Selection of Arrows · Masashi Ohara, Naoki Kawasaki, Jun Nakahama, Yogo Takada, Hitoshi Watanabe

• 2022
  For Equipment tests Published later

  Shots at fifty-five metres from compressed air, from a robot and from an archer, filmed by two cameras at 3,000 frames per second and analysed automatically: the vertical offset at the target matches the vertical component of launch speed multiplied by the time of flight. The agreement is good for the robot and weaker for the archer, which the authors put down to the variability of horizontal speed. One archer only, indoors and with no wind.

  Automatic image analysis of an archery arrow in free flight using high-speed video cameras · Riku Murakami, Hiroya Mamori, Takeshi Miyazaki, Naoya Takahashi

• 2023
  For Model Published later

  A ballistic model for aiming a traditional bow without a sight, with air drag and a launch speed of 60 m/s: at seventy metres, if the arrow leaves 3 m/s faster than the aiming calculation assumes, the impact rises by 80 cm, and if it leaves 3 m/s slower it drops by 69 cm. At that speed one metre per second is therefore worth more than twenty centimetres, against the roughly thirteen calculated for a compound at 74.5 m/s. It is a model with no measurements, in a regional journal, and the error it studies lies in the estimate of speed rather than in its variation from shot to shot.

  Physics Application in Traditional Archery: Sight-lines Method for Aiming Using a Traditional Bow · Ibnu Jihad

• 2025
  For Equipment tests Published later

  Fifty-nine Easton X10 arrows of spine 325, characterised one by one, shot from a 52 lb recurve bow on a machine over five indoor sessions at seventy metres: in the model of vertical spread, mass and mean spine account for 46.7 per cent of the variability (R² 0.467, F = 24.56, p < 0.001), with mass weighing more (beta -0.525, p < 0.001) and the heavier arrows landing lower. A single bow and a single spine.

  Improving the arrow selection process in archery: the stiffness variation pattern matters · A. Kuch, P. Laguillaumie, F. Durand, J.-F. Debril, T. Monnet

• 2025
  Against Equipment tests Published later

  The same study puts the size of the effect to the test and finds it inflated. Between the lightest and the heaviest arrow there are 0.282 grams: the ballistic model predicted over fourteen centimetres of vertical range at seventy metres, while the measured spread was 8.8 centimetres, an overestimate of about sixty per cent. The direction holds, the calculation that quantifies it does not.

  Improving the arrow selection process in archery: the stiffness variation pattern matters · A. Kuch, P. Laguillaumie, F. Durand, J.-F. Debril, T. Monnet

• 2025
  Context Equipment tests Published later

  The comparison between the two directions, within the same experiment, shows how specific the mechanism is: the vertical model accounts for 46.7 per cent of the variability, the horizontal one for 18.6 (R² 0.186, F = 6.39, p = 0.003), where mean spine (beta -0.378, p = 0.004) and the amplitude of the stiffness variation along the shaft (beta 0.325, p = 0.012) matter. Horizontally, more than three quarters of the spread stays unexplained.

  Improving the arrow selection process in archery: the stiffness variation pattern matters · A. Kuch, P. Laguillaumie, F. Durand, J.-F. Debril, T. Monnet

Status history

1. 1933 Not studied The earliest calculation of an arrow's trajectory in the bibliography already takes launch speed into account: for a 300-grain arrow launched at 180 feet per second, 5 feet per second more or less, a difference the author thinks can occur from one shot to the next, shifts the maximum range by 26 feet, or 4 per cent. It is a model, and it is about range in flight shooting, not about the height of impact on a target: there are no data yet on vertical spread.
2. 2012 Not studied The first data on archers are not about vertical spread but about the score and about speed itself. Across seven archers from the German national squads neither mean arrow speed nor its consistency enters the model of the score, with a coefficient of variation in speed between 0.23 and 0.58 per cent; in three archers from the Malaysian national squad radar measures differences of one or two kilometres per hour from one arrow to the next. They tell us how small the variability at stake is, not what the answer is: on this question there is no evidence yet.
3. 2015 Reported The first number arrives. Laboratory and field measurements with a shooting machine, checked against a validated ballistic calculation, give about thirteen centimetres of higher impact at seventy metres for every extra metre per second of launch speed, against seven centimetres for a one-metre error in distance and seven for twenty per cent more aerodynamic drag. It is a test on equipment without archers, which for a question about equipment counts as direct evidence, but it stands alone: reported.
4. 2019 Reported A shooting robot adds the mechanism from the other end: without a clicker the draw length changes from shot to shot and the arrows move up and down. The authors give no figures. In the same year a ballistic calculation puts numbers on the link between weight, speed and height: at constant bow energy half a grain more lowers the impact at seventy metres by just under a centimetre, and the weight differences measured on shafts of the same spine shift it by anything from about three and a half centimetres to more than twenty. It is a model, and together with an observation that has no figures it does not move the status.
5. 2020 Reported The same machine compares a release triggered by the clicker with a free release: the vertical spread falls when the draw length is always the same. The comparison is shown as a graph, with no standard deviations, so it adds direction rather than firmness.
6. 2022 Reported Now comes the measurement that ties the two together: the vertical offset at the target matches the vertical component of launch speed multiplied by the time of flight. The agreement is good with the robot and weaker with the one archer filmed, where the variability of horizontal speed also weighs in. A single archer takes it no further than reported, and this is the point where the claim becomes fragile.
7. 2023 Reported A model built for the traditional bow without a sight reaches the same direction from a lower speed: at sixty metres per second, a difference of three metres per second shifts the impact at seventy metres by 69 to 80 cm, more than twenty centimetres per metre per second against the thirteen calculated for a faster compound. The slower the arrow, the more the same difference weighs. It is a model in a regional journal, with no measurements: the status stays reported.
8. 2025 Reported Fifty-nine arrows of the same model shot by machine at seventy metres: mass and mean spine account for 46.7 per cent of the vertical spread, with the heavier ones landing lower, while they account for less than a fifth of the horizontal spread. The same study cuts the size down, though, because the ballistic model predicted over fourteen centimetres of vertical range and the measurement gave 8.8, an overestimate of about sixty per cent. Direction confirmed, size to be revised: it stays reported, and it stays without a group of archers.

Related

Related articles

• Why do your groups open up with distance?Double the distance and the group doubles, or a little more: what geometry and competition scores say, and how to use two distances to find what opens your group.
• Why do my arrows go left, right, high or low?Where your arrows land is a report: how to read impact patterns, and what the measurements say about the sight, the grip, bow torque and launch speed.
• How fast an arrow flies: the metres per second, what decides them and how much they matter on the targetHow many metres a second recurve and compound arrows fly, what decides launch speed, and how much speed matters on the target and for the score.

Research lines

• 29 studiesThe archer's paradox in research: from 1987 to today
• 32 studiesArrow aerodynamics: drag, boundary layer, vanes

Other claims in this domain

• CorroboratedAlong its flight the arrow loses an appreciable part of its launch speed12 studiesStatus since 2011
• CorroboratedAs it leaves the bow, the arrow flexes and snakes around the riser instead of leaving straight19 studies · 47 archers measuredStatus since 2012
• ReportedA camera-based scoring system misreads some arrows: the ones barely sticking out and the ones that shift the target face7 studies · 2 archers measuredStatus since 2017
• ReportedA chest band with fibre optic sensors measures breathing and mean heart rate with small errors, and an archer can wear it while shooting2 studiesStatus since 2019
• ReportedA compound bow stores between 70 and 100 joules and sheds about two thirds of the force at full draw4 studiesStatus since 2015

See all claims on equipment and tuning