Physique of young Xibe archers: Wang 2015 study

Five male archers of Xibo ethnicity, aged 15 to 17 and with good results in national competitions, were measured for body size, body composition, lung capacity and a few fitness tests, and compared with 18 footballers and 7 judokas. The archers averaged 174.66 cm and 63.9 kg, with an estimated body fat of 11.11% and a vital capacity of 4,772 ml. Their maximal oxygen uptake, estimated from a step test, was 2,983.9 ml per minute, lower than the footballers' (3,195.99) and the judokas' (3,225.55), and the same holds for the step test index (93.80 against 109.82 and 112.05) and for vital capacity relative to body mass.

In the fitness tests the archers were slower over 100 metres (14.62 s against 13.65 and 13.53), with no difference over 1,500 metres or in the standing long jump; in the backward shot throw (9.30 m) they beat the footballers (8.47) and fell short of the judokas (10.98). A correlation analysis of seven derived indices sorts them into three families, and the authors conclude that Xibo archers need strength endurance no lower than that of contact sports.

Height and body mass were taken with an automatic instrument, vital capacity with a spirometer, blood pressure with a sphygmomanometer and haemoglobin with a laboratory method; body fat was estimated from two skinfolds (triceps and below the shoulder blade) using Brozek's equations. Aerobic capacity came from a step test on a 45 cm platform: the resulting index was converted to maximal oxygen uptake, in absolute terms, with a regression equation. The fitness tests were 100 metres, 1,500 metres, standing long jump and backward shot throw.

In SPSS the authors computed a correlation matrix of seven indices (lean and fat mass relative to body mass and height, body mass relative to height, vital capacity per kilogram, oxygen uptake) and a dendrogram, then compared the archers with the footballers and judokas using independent-samples t tests. The paper does not say where the footballer and judoka data come from, or whether they were collected with the same instruments.

Five people are not enough for a correlation matrix of seven indices: with five points a very high correlation can arise by chance, and some are almost built in by how the indices are defined (lean mass as a share of body mass and body fat percentage are two ways of saying the same thing, and their correlation is indeed -0.997). The three groups described in the results do not match those in the abstract, and one index appears in two different groups.

Some figures do not add up. The archers' body fat is 11.11% with a standard deviation of 0.02, meaning five boys identical to a hundredth, which is hard to believe for a skinfold estimate. Haemoglobin and blood pressure are listed in the methods but never reported. The text says the archers' upper and lower body strength exceeds that of both footballers and judokas, while in the tables the judokas throw and jump further. Oxygen uptake is given in absolute terms, without accounting for the body mass of the three groups, and strength endurance, on which the conclusion rests, was not measured. The venue is a computing conference, flagged in the registry as having questionable editorial standards.

For archers, the descriptive data are all there is to keep: five young archers of good national standard had a lower estimated aerobic capacity than footballers and judokas, and explosive strength similar to theirs. That an archer has less aerobic capacity than a footballer is no surprise and says nothing about shooting, since the study relates none of its measures to score.

The conclusion that archers should train strength endurance as much as contact sports do does not come from the data: strength endurance was not measured, and a sprint or a shot throw says nothing about holding a bow at full draw through a whole competition. Nor does the study offer a basis for selecting young archers, as the authors propose.