How archers improve: Hayashi 1976 study

Six Japanese orthopaedic surgeons compared four archers from a university club with more than three years of practice against six young men who had never held a bow, using three tools together: photographs of the posture, X-rays of the elbow at full draw, and electromyography during the shot. All the subjects were male.

The first part concerns what is taught in Japan as tightening the forearm of the bow arm. The lateral X-rays show that in the expert the radius and the ulna are parallel, that is the forearm is supinated, while in the beginner the two bones cross at the elbow and the forearm sits halfway between pronation and supination. The expert's position comes from extending the elbow with the shoulder in mid-rotation, the beginner's from extending it with the shoulder rotated outwards. Why that matters the authors explain mechanically: with the shoulder in mid-rotation the deltoid is fully involved in holding the arm abducted and the biceps, being a supinator, contributes to abduction as well; with the shoulder rotated outwards the deltoid works poorly and only its anterior part is left, so the shoulder gives way to the push of the bow, the shoulder blade is driven upwards, the arm drops, the arrow point drops with it, and to raise it again the beginner leans the trunk backwards. On some subjects they also measured shoulder abduction force in the two rotations: in mid-rotation it was about twenty per cent higher.

The second part concerns the release. In the beginners the string hand stays where it was; in the experts it travels backwards, what the authors call a sliding release. And here comes the electromyographic finding: at the instant of release the muscles that fix the bow-arm shoulder stay active or increase their activity in the experts, while in the beginners they switch off. This shows on the upper and middle trapezius, on the posterior deltoid, on the triceps and, with the sharpest contrast, on the latissimus dorsi. In the beginners the bow wobbles downwards and sideways without exception; among the experts some move the bow towards the target along the line of flight, but none show downward or sideways wobble.

The experts were four male members of a university shooting team with at least three years of experience; the beginners were six young men who had never tried. The first three authors sign for the orthopaedic department of Tsukuba University, the other three for that of Tokyo University, and the work was presented at the twenty-seventh congress of the Japanese society of physical fitness and sports medicine.

Posture was documented with photographs, compared one against another between the two groups and discussed in the text: abduction of the bow arm, height of the left shoulder, lean of the trunk and neck, distance of the bow from the body, orientation of the flexor side of the elbow. The position of the forearm at full draw was captured with lateral X-rays, one for each group, in which the radius and ulna can be seen to be either parallel or crossed.

Electromyography was recorded during the shot on six muscles, named in the figures: the middle trapezius on the right side, the upper and middle trapezius on the left, the left posterior deltoid, the left triceps and the left latissimus dorsi. Each trace carries two reference arrows, the start of the draw and the release, and the comparison between groups is made by looking at whether the discharge continues, increases or stops at the second arrow. There are no amplitudes, no normalisation, no averages and no statistical tests: the figures are raw traces read by eye, with two experts and two beginners per muscle.

Shoulder abduction force in external rotation and in mid-rotation was measured on some of the subjects, whose number is not given, and the only result reported is the gap of about twenty per cent in favour of mid-rotation.

Ten subjects, four experts and six beginners, all male, in a single session: this is a descriptive study from 1976 and has to be read as such. There is no figure in it beyond the twenty per cent difference in abduction force, and that figure is reported without the number of subjects, without the instrument used and without any measure of spread. Of the electromyography nothing is quantified: no amplitudes, no normalisation to maximal contraction, no averaging across shots, no tests. The conclusions rest on reading the traces by eye, and for each muscle the figures show two experts and two beginners.

There are two X-rays, one per group: they describe two people, not two populations. The comparison, besides, does not isolate experience. The beginners had never shot, so they were learning at the same time to hold the bow, to draw it and to let the string go, and nothing is known about the draw weights and dimensions of the bows they used: a shoulder that gives way to the push of the bow may give way because the bow is too heavy for whoever is holding it.

On the forearm there is an internal discrepancy. The Japanese body text says that in the beginner the forearm sits halfway between pronation and supination, with radius and ulna crossed, while the English abstract says it is pronated. This record follows the body text.

The two most interesting readings are the authors' interpretations rather than measurements. That the sliding release is preferable because it lets the three fingers come off together and instantaneously, and so lets the string return without waving, is a piece of reasoning about the photographs. And that fixing the bow from release through follow-through is a central element of learning is a conclusion drawn from the shape of the traces: no arrow was linked to a point of impact, no score appears in the study, and there is no measurement of whether the bow movements the authors observe arrive before or after the arrow has left the string.

This source matters for one precise reason: it dates from 1976, and it uses an X-ray to describe something that coaching passes on in words. Tightening the forearm of the bow arm, in these four experts, corresponds to an identifiable joint position, shoulder in mid-rotation and forearm supinated, with radius and ulna parallel; in the beginners the shoulder was rotated outwards. The authors add that once the movement is understood even a beginner performs it easily, and that the difficulty lies in doing it consciously.

The chain they describe is the part useful to anyone teaching. With the shoulder rotated outwards the deltoid does not hold, the shoulder gives way, the shoulder blade rises, the bow arm drops, the arrow point drops and the trunk leans back to compensate: a posture faulty in five places tracing back to a single origin. It remains a description of six beginners, not a demonstration.

The second observation concerns what happens at the instant of release. In the experts the muscles that fix the shoulder keep discharging or increase, in the beginners they stop, and the beginners' bows always move downwards and sideways. Where those movements fall relative to the arrow leaving, the study does not measure, and scores never come into it: so fixing the bow at release is here a difference observed between those who can shoot and those who cannot, not a demonstrated cause of lost points.