The point where the arrow passes closest to the bow is not its tail, and that passage happens after it has left the string

The summary today

It rests on a single study, but one filmed on world-class archers. Sixteen recurve archers recorded at 4,000 frames per second release the nock from the string on average 14.7 milliseconds after the release begins; in the archer whose full sequence the authors show, the nock separates at 14.5 ms, the minimum clearance between shaft and button comes at 15.5 ms, about 150 mm from the nock, and the nock passes the button only at 18 ms, with ample room for the fletching too. In the same footage the arrow starts to roll about its axis as soon as it leaves the string, but by the time the tail passes the button the rotation is still very small, so the vanes pass the bow oriented as they were at full draw. The picture is not the same for everyone, though: the clearance with which the tail passes the button ranges from about 2 to 25 mm across the sixteen archers and follows the ratio between the arrow's two flexes, which the authors link to the way the bow hand twists the grip. Before this footage there were only mathematical models, which described contact with the button and separation from the string without saying where the arrow passes closest. A single study, with the closest point documented in detail on one archer: that is why the status is "Reported".

Also phrased as: "the tail of the arrow hits the button"; "arrow clearance past the bow"; "fletching contact with the bow"; "nock orientation and vane clearance"

Evidence

• 1997
  Context Model Published later

  A mathematical model of bow and arrow, validated on replicas of ancient bows: the arrow leaves the string when the force accelerating it falls to zero, that is when the centre of the string has already passed the braced position, because the string stretches. It explains when separation happens, not where the arrow passes closest to the bow.

  An approach to the study of ancient archery using mathematical modelling · B. W. Kooi, C. A. Bergman

• 1998
  Context Model Published later

  A model of a competition recurve with a standard arrow: contact between arrow and button is not continuous, the contact force drops to zero for an instant just after the release and then rises again, and contact ends before the arrow leaves the string. It describes the arrow resting on the button, not the clearance after separation.

  Bow-arrow interaction in archery · B. W. Kooi

• 2001
  Context Model Published later

  A simulation of two 660 mm arrows with a 202 N Olympic bow, validated against high-speed footage: the untuned arrow leaves the string after three quarters of a vibration cycle (15.5 ms against a period of 18.9 ms) and its tail rubs the grip, while the tuned one leaves at the start of the next cycle (16.2 ms against 15.6) and bends around the bow without touching it.

  Lateral deflection of archery arrows · Zanevskyy

• 2011
  Context Equipment tests Published later

  A single-cam compound on a shooting machine with a ProTour 470 arrow, photographed with a timed flash: the arrow leaves the rest about 14 ms after the release (13.83 predicted by the model), leaves the string at 17-17.5 ms and has cleared the bow by 20 ms, with a launch speed of 78.2 m/s. Here too the bow is cleared after the string lets go, but with a rest in place of the button.

  The Behaviour of An Arrow Shot from a Compound Archery Bow · J L Park

• 2012
  For Archers Published later

  16 world-class recurve archers filmed from above at 4,000 frames per second: the nock leaves the string on average 14.7 ms after the release begins (standard deviation 1.2 ms). In the archer whose sequence is shown, the nock separates at 14.5 ms, the minimum clearance between shaft and button falls at 15.5 ms about 150 mm from the nock, and the nock passes the button at 18 ms with ample room for the fletching too.

  High-speed video analysis of arrow behaviour during the power stroke of a recurve archery bow · James L Park, Oliver Logan

• 2012
  Context Archers Published later

  In the same footage the arrow starts to roll about its axis as soon as it leaves the string, but when the tail passes the button the rotation is still very small: the vanes pass oriented as they were on the string, and for the authors the nock orientation should be chosen to give the greatest clearance as the arrow passes.

  High-speed video analysis of arrow behaviour during the power stroke of a recurve archery bow · James L Park, Oliver Logan

• 2012
  Context Archers Published later

  The clearance with which the tail passes the button varies widely from one archer to another and goes with the ratio between the first and second flex: 8-10 mm in 9 archers with a ratio of 0.6-0.8, 2-5 mm in 5 archers with a ratio of 0.4-0.6, 12 mm in one with a ratio of 0.9 and 25 mm in one with a ratio of 1.0. The authors link it to the bow hand twisting the bow, which they infer from the images rather than measure.

  High-speed video analysis of arrow behaviour during the power stroke of a recurve archery bow · James L Park, Oliver Logan

• 2012
  Context Model Published later

  A recurve simulation checked against measurements: two shafts with the same nominal spine do not pass the button in the same way, because the more flexible tail of the X10 gives it 11 mm of clearance against 9 mm for the ProTour, even though the X10 is 4% stiffer overall.

  Arrow behaviour in the lateral plane during and immediately following the power stroke of a recurve archery bow · James L Park

Status history

1. 1997 Not studied The first piece is a mathematical model built for ancient bows: the arrow leaves the string when the force driving it falls to zero, that is when the centre of the string has already passed the braced position. It says when separation happens, not where or when the arrow passes closest to the bow: on this question there is no evidence yet.
2. 1998 Not studied The same approach applied to a competition recurve describes how the arrow rests on the button: just after the release contact breaks for an instant and then resumes, and it ends before the arrow leaves the string. That is the mechanism leading up to the passage, not the passage itself: the question stays open.
3. 2001 Not studied A simulation validated against high-speed footage shows what happens when the tuning gets the timing off: the untuned arrow leaves the string three quarters of the way through its vibration cycle and the tail rubs the grip, while the tuned arrow bends around the bow without touching it. It is still a model, and it looks at the tail: nobody has measured where the arrow passes closest.
4. 2011 Not studied The first measurements with a timed flash come from a compound on a shooting machine: the arrow leaves the rest at about 14 ms, the string at 17 and has cleared the bow by 20. The order of events matches the claim, but the bow is a compound with a rest and there is no archer: for the recurve the question still has no data.
5. 2012 Reported Footage of sixteen world-class recurve archers at 4,000 frames per second arrives. The nock leaves the string on average at 14.7 ms; in the archer shown in sequence the minimum clearance between shaft and button falls at 15.5 ms, a millisecond after separation, about 150 mm from the nock, and the vanes pass having barely rotated. The tail clearance, though, ranges from 2 to 25 mm from one archer to the next, and a simulation from the same year shows that the shaft's stiffness profile changes it too. A single study on archers: reported.

Related

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• The archer's paradox: the physics of the flexing arrowAt full draw the arrow points to one side and still reaches the centre: how it flexes and clears the riser in the first twenty milliseconds, and how spine matches it to the bow.
• The release in archery: anatomy of a few millisecondsHow the archery release works according to the measurements: how long it lasts, how the fingers open, what the arrow does and what you can train.

Research lines

• 29 studiesThe archer's paradox in research: from 1987 to today
• 17 studiesGrip pressure and bow torque: from 1971 to today

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