Physical demands in two archers: Borges 2020 study

Two archers, not two groups. A sixteen-year-old elite member of the Brazilian junior national team, with five years of practice and two as a professional, silver at the World Cup in Lausanne in 2014, silver at the Youth Olympic Games in Nanjing and gold at the under-18 World Cup in Yankton in 2015; and a sixteen-year-old with nine months of practice as an amateur. Both take on a simulated competition in the official format, a double round at seventy metres, twelve ends of six arrows, seventy-two arrows in all.

Every two ends, perceived exertion, lactate and glucose from a drop of blood from the earlobe, the grip strength of both arms and the electromyography of the superficial finger flexor of the right forearm are measured, the last of these during a maximum voluntary contraction rather than during shooting.

The elite archer stays stable throughout. The grip strength of the dominant arm does not fall, the median frequency of the electrical signal goes from 146 to 140 hertz, lactate stays close to resting values and perceived exertion does not move. The only value that changes is the amplitude of the signal during the maximum contraction, which falls from 0.279 to 0.221 volts, that is by 20.7 per cent, and the authors offer no reading of this.

The novice pays more for the same number of arrows. Grip strength falls from 80.2 to 71.5 pounds on the dominant arm, that is by 10.8 per cent, and from 75.0 to 70.0 on the other. The amplitude of the electrical signal during the maximum contraction rises from 0.387 to 0.720 volts, plus 46.2 per cent, that is more activation is needed to produce less force, which is the classic signature of fatigue. Lactate rises from 1.5 to 2.8 millimoles after the tenth end, and perceived exertion goes from zero to five on the scale.

Glucose stays stable in both, between 87 and 107 milligrams per decilitre.

The authors' conclusion is cautious and deserves reporting as they write it: all the fatigue markers show a mild response to the simulated competition, with a greater magnitude in the novice. Seventy-two arrows at seventy metres, in other words, are a light metabolic demand even for someone who has been shooting for nine months.

Approval from the ethics committee of the School of Arts, Sciences and Humanities of the University of São Paulo, with a protocol number, and participants informed about procedures and risks.

The two archers are described one by one. The elite archer is sixteen, seventy-six kilograms, one hundred and eighty-two centimetres, with five years of practice and two as a professional, with the international results listed. The novice is sixteen, seventy kilograms, one hundred and seventy-one centimetres, with nine months of practice as an amateur. Both are right-handed.

The simulated competition follows the official format: a double round at seventy metres, twelve ends of six arrows. Measures are taken at the start, after each end from the second to the twelfth, and thirty minutes after the finish.

Perceived exertion with the CR-10 scale. Lactate from a drop of blood from the earlobe, read with a YSI Sport 1500 analyser; glucose with a portable Accutrend monitor. Grip strength with a digital Jamar Plus dynamometer on both arms, with maximum voluntary contractions of about five seconds and consistent verbal encouragement at baseline and after every two ends.

The electromyography covers one muscle only, the superficial finger flexor of the right forearm, with surface silver and silver chloride electrodes placed longitudinally over the muscle belly twenty millimetres apart, an input impedance of 50 megohms, a gain of one thousand, the reference electrode on the sternal notch, and sampling at two thousand hertz. The signal associated with the maximum contraction was filtered with a fourth-order Butterworth between twenty and five hundred hertz, and the root mean square computed over windows of fifty milliseconds. For each contraction the most stable two-second interval was taken, that is the one with the smallest coefficient of variation, and from it the mean amplitude and the median frequency were computed, the latter with the fast Fourier transform as the frequency dividing the power spectrum in half.

The analysis is declaredly descriptive: the pattern of force, amplitude and median frequency is assessed across the simulated competition, with no statistical test. With two participants that is the correct choice, and it deserves acknowledging.

For the values of each individual end the article refers to Figure 1, which a text extraction does not return: the numbers reported in this card are those cited in the text of the results.

These are two people, and the title says effect of experience level. With one archer per level, any difference between the two is a difference between two individuals and cannot be put down to level: the elite archer is also eleven centimetres taller, six kilograms heavier and a world medallist at sixteen, that is he brings with him everything that goes with being an international talent. The article is a case series presented with the language of a group study, and the abstract speaks of having investigated the effect of expertise level. In the registry it should be cited as two stories, not as a comparison between levels.

It should be said at once, though, that the authors did not do the worst thing: they ran no statistical test at all. With two participants that is the right choice, and in this batch it is not the rule.

One sentence of the results does not match its own numbers. It says the novice shows a minor decrease in median frequency from the sixth to the end of the twelfth end, and then lists 122 hertz at the second, 127 at the fourth, 112 at the sixth and 117 at the twelfth, with minus 4.1 per cent. That minus 4.1 per cent is the move from the second to the twelfth, from 122 to 117; from the sixth to the twelfth, from 112 to 117, the value rises by 4.5 per cent. The series, besides, does not fall steadily but oscillates, so across four measurement points the word decrease describes a pattern the numbers do not have.

The amplitude of the electrical signal was not measured during shooting but during a maximum grip contraction performed every two ends. It therefore measures the fatigue of the finger flexor in a strength test, not the activation in the movement: an archer reading this card should not think it concerns how hard the muscle works while shooting. The muscle measured is a single one, of the forearm, and of the shoulder muscles, which are the ones meant when fatigue in archery is discussed, there is nothing.

For the elite archer there is one number the article leaves unexplained, and which the abstract does not name among the changes: the amplitude during the maximum contraction falls by 20.7 per cent. In the novice the same measure rises by 46.2 per cent while force falls, and that is the coherent picture of fatigue, more activation for less force. In the elite archer it falls while force stays stable, that is the two go in opposite directions, and no reading of that fall is offered. A drop of a fifth in a measure of maximal activation is not a detail.

Every number is a single measurement on a single person, with no estimate of the instrument's variability. A fall of 10.8 per cent in grip strength, in a sixteen-year-old across a session of seventy-two arrows, sits within the order of magnitude by which grip dynamometry varies from trial to trial and from day to day: without repeated trials, fatigue cannot be told from the noise of the measure.

Finally the reach of the metabolic values, which is the most useful datum and also the most modest. The novice's lactate reaches 2.8 millimoles, which remains a value only a little above rest, and glucose does not move in either archer. The increase of 86 per cent, read alone, sounds large; read in millimoles it says that seventy-two arrows do not constitute a metabolic demand. The authors write as much, calling the response of all the markers mild, and on that this card agrees.

The firmest datum in this work is also the most sober: a competition of seventy-two arrows at seventy metres is not a metabolic demand. The elite archer's lactate stays close to resting values across all twelve ends, the novice's reaches 2.8 millimoles, which is just above rest, and glucose does not move in either. Anyone planning nutrition or recovery around a competition in this format is working with a light load rather than an endurance effort.

The second thing is the difference between the two, which must however be taken for what it is: two stories. The novice, for the same number of arrows, loses 11 per cent of his grip strength, needs almost 50 per cent more activation to produce a maximum contraction and reaches five out of ten in perceived exertion, while the elite archer stays stable throughout. In the terms of a shooting hall: the same seventy-two arrows cost far more to someone shooting for nine months than to someone shooting for five years, and the difference shows in the forearm and the hand. For a coach that is a reason to set volume by level, not a number to apply.

What this study does not say concerns the shoulder, which is the region meant when fatigue in archery is discussed. The only muscle measured is the finger flexor of the forearm, and the measure is taken during a grip test between ends rather than during shooting. So there is nothing on what happens to the shoulder girdle across the seventy-two arrows.

And it says nothing about level as a category. One archer per level is not a comparison between levels: the difference observed is between two sixteen-year-olds who also differ by eleven centimetres in height, six kilograms and four years of practice, and one of the two is a world medallist. The registry keeps this work as two well-described cases, useful for the order of magnitude of the metabolic cost of an official round and for the direction of the gap between an expert and a beginner, and not as evidence about what level entails.