Matteo Campagna
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The passive release: fifty years of measuring the fingers, the muscles and the clicker

For decades the release was taught as a relaxation: the fingers do not open, they let go. This page follows the studies that have measured it from 1971 to the present, with electromyography, high-speed cameras and clicker timers, and sets out what is left of that idea.

Studies in the registry
24
On archers
20
Years
1971-2026

The question

Among the rules of the release there is one that almost every recurve archer hears early on: the fingers do not open, they relax, and the string leaves on its own. It is a powerful image, because it describes what a good release looks like, and it rests on a specific assumption: an archer who opens the fingers actively pushes the string sideways and spoils the shot. In the registry this idea is a refuted claim, since 1990, and the measurements that bear on it span more than fifty years.

This page follows the studies in chronological order. Practical advice is in the articles on the release and the clicker; here the subject is what has been measured, with which instruments, and how much the results weigh.

1971-1990: the idea meets electromyography

The first observation points the same way as the rule. In 1971 a Japanese group recorded fourteen muscles in three kyudo practitioners: at the release the beginner activated every muscle of the upper trunk, while the expert relaxed them together. There were three people, and the muscles recorded were in the trunk: about the fingers the study said nothing.

The first measurement of the hand, in 1987, pointed the other way. Another Japanese group filmed a skilled archer at 200 frames per second with five electromyographic traces overlaid: the fingers began to open 25 milliseconds before the string left, and the finger extensor switched on just as the deltoid fell silent. In twelve archers grouped by level, that deltoid silence appeared in 70-100% of the best group's shots and less often in the others, but the groups' scores were not reported and there was no statistical test.

The study that carries the most weight came in 1990. Fifteen highly skilled archers, nearly all from the US national team, shot six arrows each with electrodes on the finger flexor and extensor. The release fell into two stable patterns: eight archers let the activity of both muscles drop, seven showed a short burst of extensor activity in the 200 milliseconds before the release, and each archer always repeated their own. Mean season scores were almost identical, 1,209 for those who relaxed and 1,213 for those who opened, out of 1,440. The means were not compared with a test and the groups were small, but two ways of releasing, at the same level and with the same results, removed the ground the prescription stood on.

2003-2022: the extensors work in elite archers too

In 2003 a laboratory in Ankara measured three groups of ten: elite Turkish national team archers, club beginners and people who had never shot. In all three, after the clicker snap, the finger extensor contracted while the flexor gave way gradually. The elite archers relaxed the flexor faster, and only one of them, a woman ranked in the world top ten, showed the drop in extensor activity that the rule would prescribe. A second paper from the same laboratory in 2005 found the same pattern in a partly overlapping sample, so it is not an independent replication.

Later studies described the mechanism rather than challenging it. In data from four archers who had competed for Turkey, collected in Nicosia and published twice, in 2010 and 2011, the flexor drops from 83.2% to 33.3% of maximum contraction in the second around the clicker, while the extensor stays at 57.7%. In ten Brazilian national team archers shooting at 70 m, flexor and extensor follow opposite courses, and each moves together with different arm muscles, with correlations above 0.9. In 2022 a systematic review of 41 studies brought the electromyographic work together and concluded that relaxed fingers do not produce better scores than active extension.

What can be seen and what happens under the skin

Meanwhile cameras confirmed the shape the rule describes. In 2012 sixteen world-class archers, filmed at 4,000 frames per second, showed fingers that stay curled: on average the string clears them in 1.9 milliseconds, too short a time for any opening decided in the moment. In 2024, in competition footage of 30 elite archers, 28 let the string go with relaxed fingers and 2 opened them. The two findings fit together, because the extensor can switch on without the fingers straightening: the visible shape of the hand is the result of the release, not the instruction that produces it.

The only three-dimensional measurement of the hand in the registry comes from one Austrian archer filmed at 500 Hz in 2009. The opening happens at the middle and end joints, while the knuckles move 6-9 degrees, and how fast the middle finger opens does not separate Xs from arrows scoring 8 or lower. Revisiting the same arrows in 2011, the authors found that a wider sideways deviation of the string went with higher scores, the opposite of what the case for a passive release assumes. It remains a single case.

Before the release: the flexors and the clicker

Alongside the rule a related question has grown up: whether the draw hand is already more relaxed before the snap on the better arrows. In the same four Turkish archers, at 18 m, the finger flexor was at 80.0% of maximum on 10s and 85.6% on 8s, with a weak correlation (r = -0.29). In 2025 eight high-level French archers, over 549 arrows at 70 m, gave the opposite result, with flexor and extensor more active on 10s. Distance, number of archers and time window all differ, and the claim is now contested.

The idea that the release is a reaction to the click has its own history. In 1998 nine German national team archers released after the clicker faster than they could react to a sound, in seven of nine on the simple task and in all nine on the task closest to shooting: by the time the click arrived, the movement seemed to be under way already. Later measurements (142-143 milliseconds in four Turkish archers, between 144 and 176 with a microphone in Germany, 163 on average across 39 elite archers) describe how long the interval lasts rather than what it is, and nobody has repeated that comparison on the same archers.

How long the release lasts

The figure in circulation, three hundredths of a second, comes from an accelerometer fitted in 1987 to the bow of a single Italian national team archer, and was found again in 1994 in twelve archers at a resolution of one hundredth. The 2012 footage at 4,000 frames per second gives 14.7 milliseconds from the start of the release to the nock leaving the string, about half as long. The instruments differ, an accelerometer with a switch in 1987 and the image in 2012, and for now the figure is contested.

What remains open

What survives of the rule is the description, since seen from outside the best archers' fingers stay curled. The prescription does not: in the only study that compared the scores of archers who relax and archers who open their fingers the means are almost identical, and in the others the extensor works in the best archers too. The study that would settle the matter is still missing, one that links the way an archer releases, measured with electromyography and high-speed video, to where each arrow lands, or a comparison in which the two methods are taught to separate groups. Almost all the data come from Olympic recurve and from skilled archers; for compound with a release aid and for barebow the registry has nothing.

How we came to know it

  1. 1971OriginKamei et al. 1971 An Electromyographic Analysis of Japanese ArcheryElectromyography in three kyudo practitioners: at the release the beginner activates every upper-trunk muscle, while the expert relaxes them together. It looks at the trunk, not the fingers.
  2. 1987ContradictionNishizono et al. 1987 Analysis of Archery Shooting Techniques by Means of ElectromyographyIn one skilled archer filmed at 200 frames per second the fingers start to open 25 ms before the release, and the finger extensor switches on while the deltoid falls silent; among the best of 12 archers that silence appears in 70-100% of shots.
  3. 1987MethodLeonardi et al. 1987 Reduction of Lateral Bow Displacement Using Different Torque Flight Compensators and Stabilizers in ArcheryAn accelerometer on the bow of an Italian national team archer, sampled at 2,500 Hz, gives about 30 ms from the start of the limbs' return to the arrow leaving the string.
  4. 1990ContradictionMartin et al. 1990 Electromyographic analysis of bow string release in highly skilled archersIn 15 highly skilled archers, nearly all from the US national team, the release follows two stable patterns: 8 relax the finger muscles, 7 show a burst of extensor activity in the preceding 200 ms. Mean season scores are 1,209 for those who relax and 1,213 for those who open, out of 1,440.
  5. 1994ReplicationSquadrone et al. 1994 Multifactorial analysis of shooting archeryIn 12 Italian archers the release phase lasts about 0.03 s, which is three frames at 100 Hz: too few to analyse.
  6. 1998ExtensionEdelmann-Nusser et al. 1998 Coordinative Aspects of Archery - An Approach Using Surface-ElectromyographyIn 9 German national team archers the interval from clicker to release is shorter than their reaction time to a sound, in 7 of 9 on the simple task and 9 of 9 on the task closest to shooting: the release appears to be already under way.
  7. 2003ReplicationErtan et al. 2003 Activation patterns in forearm muscles during archery shootingTen elite Turkish national team archers, ten beginners and ten people who had never shot: in all three groups the finger extensor contracts after the clicker while the flexor gives way gradually.
  8. 2009MethodHorsak et al. 2009 A Kinematic Analysis of Finger Motion in ArcheryMotion capture at 500 Hz on the hand of one Austrian archer: the opening happens at the middle and end joints, the knuckles move 6-9 degrees, and middle-finger speed does not separate Xs from 8s or lower.
  9. 2010ExtensionErkek et al. 2010 Shooting Dynamics in ArcheryFour elite women archers who had competed for Turkey, 108 arrows at 18 m: in the second before the clicker the finger flexor is at 80.0% of maximum on 10s and 85.6% on 8s (r = -0.29); clicker to release takes 142-143 ms on every kind of arrow.
  10. 2011ExtensionHorsak et al. 2011 A Three-Dimensional Analysis of Finger and Bow String Movements During the Release in ArcheryThe same 56 arrows as in 2009: on poor arrows the curve of the middle-finger knuckle varies more, and a wider sideways deviation of the string goes with higher scores.
  11. 2012ReplicationHeller 2012 Evaluation of arrow release in highly skilled archers using an acoustic measurement systemA microphone on 7 German national team archers gives individual means of 144 to 176 ms from clicker to release, in a third laboratory.
  12. 2012ContradictionPark et al. 2012 High-speed video analysis of arrow behaviour during the power stroke of a recurve archery bow16 world-class archers at 4,000 frames per second: the fingers stay curled, the string clears them in 1.9 ms and the nock leaves the string 14.7 ms after the release begins, about half the 30 ms of 1987.
  13. 2014ExtensionSimsek et al. 2014 Kinetic and Kinematic Analysis of Recurve Archery Shooting Technique27 archers at three levels: before the clicker beginners hold the forearm above their own voluntary maximum and elite archers lowest of all; after the snap, flexors and extensors fall together in the elite group and move in opposite directions in beginners.
  14. 2017ReplicationSpratford et al. 2017 Postural stability, clicker reaction time and bow draw force predict performance in elite recurve archery39 elite archers at a World Cup stage: 163 ms on average from clicker to release, with 10% variation between archers.
  15. 2018ExtensionMachado 2018 Temporal pattern in the muscles of the upper limbs and the trunk in the archery10 Brazilian national team archers, 72 arrows at 70 m: finger flexor and extensor follow opposite courses around the clicker, and each moves together with other arm muscles.
  16. 2022ReviewVendrame et al. 2022 Performance assessment in archery: a systematic reviewA systematic review of 41 studies concludes that releasing with relaxed fingers does not give better scores than releasing with active extension.
  17. 2023ExtensionSong et al. 2023 Multi-muscle Synergies of Postural Control in Self- and External-Triggered Force Release During Simulated Archery ShootingEight people with no archery experience, on a simulated draw, take 318 ms to release after a visual signal: about twice the archers' clicker-to-release interval.
  18. 2024ReplicationShafizadeh et al. 2024 Technical performance differences in elite Olympic recurve archersIn competition footage of 30 elite recurve archers, 28 let the string go with relaxed fingers and 2 open them.
  19. 2025ContradictionJacquot et al. 2025 A multi-parameter investigation of elite archery: distinguishing individual and shared performance strategies during the aiming and follow-through phases8 high-level French archers, 549 arrows at 70 m: throughout the aim the finger flexor and extensor of the draw hand are more active on 10s than on 8s or lower, the opposite of the 2010 study.

Studies in this line

Related claims

Claims in the registry with at least one of these studies among their evidence.

111 claims · 89% with evidence on archers

Articles

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Cite
APA

Campagna, M. (2026). The passive release: fifty years to take an idea apart. In Research. matteocampagna.com. Retrieved 16 October 2026, from https://matteocampagna.com/en/research/passive-or-active-release

BibTeX
@misc{campagna2026_enresearchpassiveoractiverelease,
  author = {Campagna, Matteo},
  title = {The passive release: fifty years to take an idea apart},
  year = {2026},
  howpublished = {Research, matteocampagna.com},
  url = {https://matteocampagna.com/en/research/passive-or-active-release},
  note = {accessed 2026-10-16}
}