In expert archers the deltoid falls silent just before the release

The summary today

Only one Japanese group has measured it, in 1987. Twelve archers split into three levels by their usual score shot twenty arrows at eight metres: in the best group the deltoid fell silent for an instant on 70 to 100 per cent of shots, 110 to 120 milliseconds after the clicker went off, that is about sixty milliseconds before the release, which came at 170 to 180; in the other two groups the silence appeared less often. The authors rule out simple inhibition by the antagonist muscle, because the pectoralis major stays almost still while the deltoid is silent, and they note that this is exactly when the finger extensor starts working, with the fingers opening 25 milliseconds before the release. In the beginners measured in the same work, the silence is replaced by a sudden burst in the drawing arm. The picture is consistent, and a 2005 review reports changes in tension about sixty milliseconds before the release in two experienced archers, but the limits are clear: one group, eight metres, no statistics between levels and no link to the score of the individual arrow.

Also phrased as: "muscle silent period"; "clean release"; "shoulder switching off at release"; "electromyography of the release"; "no jerk in the drawing arm"

Evidence

• 1987
  For Archers Published later

  12 Japanese archers aged 18 to 24, split into three groups by their usual score, 20 arrows at 8 metres: in the most skilled group the deltoid silence appears on 70 to 100 per cent of shots, with a latency of 110 to 120 milliseconds from the clicker and a release reaction time of 170 to 180; in the other two groups it appears less often. The group scores are not reported, nor how many archers were in each, and there is no comparison test.

  Analysis of Archery Shooting Techniques by Means of Electromyography · H. Nishizono, H. Shibayama, T. Izuta, K. Saito

• 1987
  Context Archers Published later

  During the deltoid silence the pectoralis major shows only a small deflection from baseline, from which the authors rule out simple reciprocal inhibition between agonist and antagonist; the finger extensor starts to activate exactly while the deltoid is silent, and filming at 200 frames per second shows the fingers opening 25 milliseconds before the release, with arm and shoulder still. In the first study of the same work, on 5 archers, the two champions (a winner of the Japanese field championship and a US Open winner) show a clean cessation of muscle activity at release followed by back and shoulder activity that holds at the same level for 1.5 to 1.7 seconds, while in the two beginners the release comes with a sudden burst on the drawing side. These are single traces described in words.

  Analysis of Archery Shooting Techniques by Means of Electromyography · H. Nishizono, H. Shibayama, T. Izuta, K. Saito

• 2005
  Context Review Published later

  A review chapter reporting a 1990 study of 2 experienced archers, with electrodes on 7 upper-limb muscles recorded from 120 milliseconds before to 60 after the release: muscle tension changes about 60 milliseconds before the release, ahead of the release of forces at the joints, and the author reads it as a sign of an automatic movement. It is a cited figure, not measured in the chapter.

  Psychological Aspects of Archery · Kathleen M. Haywood

Status history

1. 1987 Reported A Japanese group presents two electromyographic studies at a biomechanics conference. In the first, on five archers, the two champions abruptly stop their muscle activity at the moment of release, while the beginners show a sudden burst on the drawing side. In the second, on twelve archers at three levels and twenty arrows at eight metres, the deltoid silence appears on 70 to 100 per cent of shots in the most skilled, 110 to 120 milliseconds after the clicker and about sixty before the release, and less often in the others. It is a single group, with levels defined by scores it does not report, no statistics and a laboratory distance: reported.
2. 2005 Reported A review chapter on the psychology of shooting reports a 1990 study of two experienced archers, with electrodes on seven upper-limb muscles from 120 milliseconds before to 60 after the release: muscle tension changes about sixty milliseconds before the string goes, ahead of the release of forces at the joints. The timing matches that of the deltoid silence measured in 1987, but it is a second-hand figure on two people, not a replication: the status holds.

Related

Related articles

• Which muscles work in an archery shot, and at what share of their maximumWhich muscles switch on in an archery shot, in which phase and at what share of their maximum, and why studies give different figures for the same muscle.
• 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

• 24 studiesThe passive release: fifty years to take an idea apart
• 52 studiesMental training: what has been tested on archers since 1979

Other claims in this domain

• CorroboratedBetween one and a half and two tenths of a second pass between the clicker sounding and the arrow leaving7 studies · 94 archers measuredStatus since 1990
• ReportedA camera diagonally behind the archer measures the vertical sway of the aim well, but not the horizontal1 study · 3 archers measuredStatus since 2010
• ReportedA continuous final pull through the clicker leads to better shots9 studies · 56 archers measuredStatus since 1993
• ReportedA sound or light cue about the angle of the bow arm tightens beginners' groups2 studies · 1 archers measuredStatus since 2012
• ReportedA thumb grip on the string is less tiring than a finger grip3 studies · 9 archers measuredStatus since 1990

See all claims on technique and biomechanics