Archery technique and physical effort: Stone 2007

The study starts from an ergonomics question: if a set of shooting techniques is ranked by the strain it places on the body, does that ranking predict who will score higher? To keep habit out of the way, the author used only people who had never shot before.

Sixteen participants, eight men and eight women aged between twenty-one and twenty-five, were randomly assigned to one of the eight possible combinations of four foot positions, namely even, closed, open and oblique, and two string grips, namely the thumb grip and the reverse grip: two people per combination. Each shot eighty arrows with electrodes on the trapezius, biceps brachii and extensor digitorum, after an hour of on-site training and thirty settling arrows.

Before the experiment, a biomechanical assessment had ranked the eight combinations by overall ligament strain, from the even stance with thumb grip to the oblique stance with reverse grip. The results follow that ranking. Scores were highest with the even stance, then with the open and closed stances, which were indistinguishable from each other, and lowest with the oblique stance; both foot position and grip come out as relevant factors, and so does their combination.

The largest result concerns the grip. With the reverse grip, activity in the trapezius and extensor digitorum was higher, and the score of the participants using the thumb grip was on average 77 per cent above that of the reverse grip, across all stances. Scores then fell by about eight per cent from one measurement session to the next across all conditions, with the fall arriving earlier and more sharply in the reverse grip group. Electromyography, by contrast, did not separate the four foot positions: the author expected this, since the muscles measured sit in the upper body. The difference between stances comes instead through ligament strain and, in the video observation, through body sway, which in the oblique stance grew steadily over the course of the trial.

The two independent variables are the string grip, at two levels, and the foot position, at four. The two grips were chosen because earlier work had found them the furthest apart in muscle activity. The foot positions are the four in common use. The dependent variable is the score, which the paper describes as the points gained over the eighty arrows, along with muscle activity measured by surface electromyography.

Before the experiment a biomechanical assessment ranked the eight combinations by overall ligament strain. Each participant was randomly assigned to a combination and received the instruction documentation a week in advance, to shorten on-site training.

The session was held at a commercial archery range, in two slots of about four hours with four groups of four people. Ten minutes for consent and the demographic sheet, twenty minutes of instruction on range safety and procedure with equipment handed out, forty minutes of on-site training to check that each person was adopting the assigned position, an hour with thirty arrows and no data collection, so that the position would become second nature, and finally two hours of measurement with electromyography and scoring.

Electrodes were placed on the trapezius, biceps brachii and extensor digitorum following a reference manual for surface electromyography, and the maximal voluntary contraction of each muscle was recorded immediately afterwards for normalisation. Since it was not possible to monitor everyone at once, participants were staggered by ten-arrow rounds, so that each was measured at the same relative level of fatigue. The measurement windows for muscle activity are three: the first ten arrows, arrows forty to forty-nine, and arrows seventy to eighty. The analysis is a series of analyses of variance followed by Tukey post hoc comparisons.

No participant had ever shot before, and this is a stated choice rather than an oversight: the author wanted previous learning out of the way. The price is that the result concerns the first afternoon of shooting for sixteen people, not the shooting of an archer. Which foot position suits someone who has shot for years, with the musculature and the control that come with it, this design cannot say, and the author himself explains the poorer stability in the oblique stance by fatigue and the lack of the muscular development an experienced archer has.

The design is tiny in every cell. Sixteen people split across eight combinations gives two participants per combination: a difference between two foot positions rests on four people per side. No F values are reported, no exact p values, and no mean scores in points: the only figure is the 77 per cent difference between the two grips, and the chart shows normalised values. A 77 per cent difference in score between two string grips, in beginners, says more about one of the grips being unmanageable than about a measurable effect on shooting.

The equipment and shooting protocol are missing. Nothing says the distance, the target, the bow type or the draw weight, or even whether everyone used the same equipment, which was on loan from the range. The paper's definition of the score, the points from the eighty arrows multiplied by ten, matches no competition format, which makes it hard to see on what scale the 77 per cent was computed.

Finally, ligament strain, the variable the whole prediction rests on, was not measured during the trial: it comes from a biomechanical assessment made beforehand, by a method the paper does not describe. The observation about body sway in the oblique stance comes from video, without measurement. The thumb grip, moreover, is not the grip of Olympic archery, where three fingers are used: the comparison covers two grips chosen because they are far apart, not two current alternatives on the shooting line. The venue is conference proceedings and the peer review status is not known.

This study concerns the first eighty shots in the lives of sixteen people, and that is the only thing it can be cited for. Under those conditions the simplest foot position to hold, the even stance, gave the highest scores, the oblique the lowest, and open and closed sat in between without separating from each other. The order matches what an assessment of ligament strain had predicted before anybody shot.

It is not an argument about which stance suits an archer. Those who have shot for years have built the strength and control that were missing here, and the author explains the difference by exactly that absence: the position that costs least to someone without training is not thereby the position that scores best for someone who has it. The study follows nobody over time and compares no archers.

On the largest figure, the 77 per cent difference between the two string grips, double caution is in order. The two grips were chosen because they lay far apart in muscle activity, and neither is the three-finger grip of Olympic archery. What the figure says is that for a beginner a grip demanding more work from the forearm costs points, and that fatigue arrives sooner: a phenomenon the paper also measures in the general fall of about eight per cent from one session to the next, across all conditions.