Posture before the shot in archers: Na 2024 study

Eighteen men, nine archers competing at national and international level with 16.6 years of practice on average and nine university students who had never shot, performed the shooting movement standing on two force plates, with a bow carrying a laser pointer and no arrow, aiming at a target 10 metres away. The study looks at the hundredths of a second around the release and divides that window into four stretches: the baseline, an anticipatory stretch from 100 milliseconds before to 50 after the release, and two compensatory stretches up to 350 milliseconds after.

In the expert archers the centre of pressure was already moving in the direction opposite to the coming push before the string left the fingers; in the novices it moved in the same direction as the push, and the difference at the moment of release is significant (p < 0.05, d = -1.01). After the release the peak displacement was of similar size in the two groups, but it arrived much sooner in the experts (p < 0.05, d = -1.26). The muscles show the same pattern: in the experts the electrical activity of the lower leg and thigh peaked in the anticipatory stretch and then dropped, while in the novices it grew after the release in every muscle except the right biceps femoris. The bow swayed less in the experts, but only vertically (p < 0.05, d = 1.41): fore and aft and sideways the two groups were indistinguishable.

Participants stood barefoot, one foot on each plate (Bertec FP4060-08), feet a comfortable width apart and eyes open. The bow, 1.65 metres long and weighing 1.3 kilograms, was handed over by the researcher and rested on the left instep; on a go signal the archer drew, anchored the right hand on the chin, aimed the laser at the centre of the target, released at a moment of their own choosing and held the aim for a further three seconds. Each person made two shots, with a minute of rest in between. The experts warmed up with their usual routine; the novices were given a basic explanation of the release by a university team coach and five practice attempts, no more, so that they would not learn during the experiment.

Eight Vicon cameras at 100 hertz followed two markers, one on the back of the right hand and one on the front of the bow; the plates sampled at 1,000 hertz. Surface electromyography, at 2,000 hertz, recorded eight muscles: tibialis anterior, medial gastrocnemius, rectus femoris and biceps femoris in both legs. The moment of release was defined from the acceleration of the marker on the drawing hand, at the point where it exceeds five per cent of its maximum, checked by eye on the traces. The two groups were compared with independent t tests for bow sway and centre of pressure, and with a repeated measures analysis of variance for the muscles.

The authors put the heaviest limitation first: for safety reasons nobody shot arrows, so the link between what the body does before the release and performance on a shooting line was not measured. There is no score, no grouping, not even a measure of how steady the laser stayed on the centre. The authors also note that they recorded only eight muscles of the lower body, few for a balance held by ventral, dorsal and lateral chains, and that their sample is small and homogeneous, which makes the finding hard to extend.

There is more. The novices were not weaker archers, they were people who had learnt the movement ten minutes earlier: the difference may reflect familiarity with a new action as much as years of training. Each person made only two shots, and two shots are few for a measure as variable as the centre of pressure. The two groups also differed in build, 88.1 kilograms against 79.2 and 1.79 metres against 1.73, and both mass and height feed into balance measures. Finally the data are not public: the authors state that they cannot be shared.

The study describes something an experienced archer does without noticing: the body prepares for the jolt of the release before the release happens, shifting weight against the push that is about to arrive, and for that reason it settles back sooner. In the beginner the same correction comes afterwards, as a reaction, and the bow moves more in the vertical direction.

What the work does not say matters just as much: it measures no scores, compares no release techniques and points to nothing anyone can do to bring that correction forward, since it is an adaptation built over years of shooting and not a position to adopt. In the registry it serves as a description of postural control around the release and as a measure of the gap between those with those years behind them and those with none; it does not claim that working on balance raises the score, because here there is no score.