Arm strength and archery score: Putra 2022 study

Thirteen archers from Surakarta, Indonesia, took four fitness tests and a shooting test, and the authors calculated how closely each test tracked the score. All the reported correlations are very high: 0.890 for arm strength, 0.881 for arm endurance, 0.903 for abdominal strength and 0.884 for balance, all with p below 0.01. Taken together the four measures give a multiple correlation R of 0.921 (p 0.002), which the authors describe as a "perfect" relationship. The mean shooting score was 310.77, ranging from 290 to 323.

In the same table the four fitness tests correlate with one another almost as strongly (0.872 to 0.938): whoever did well on one did well on all. That is why the multiple R is barely above the highest single correlation, and the study cannot say which of the four qualities matters, if any of them does.

The study is correlational, with a sample chosen at the researchers' discretion (purposive sampling) from athletes in Surakarta. The variables are arm strength, arm endurance, abdominal strength, balance and shooting score; the correlation table labels them push-up, plank, sit-up, balance and achievement, so the tests were most likely push-ups, a plank hold, sit-ups and a balance test.

The paper, though, describes no protocol: we do not know how or for how long repetitions were counted, which balance test was used, at what distance and over how many arrows the score was shot, or with what bow. Age, sex, experience and level are not reported. The analysis consists of a Lilliefors normality test, a linearity check in SPSS, Pearson correlations and a multiple correlation.

The descriptive data contain impossible values. For arm strength the mean is 13.23 while the minimum is 15 and the maximum 60; for balance the mean is 13.08 with a minimum of 25. A mean cannot be lower than the lowest value, so at least part of the table was transcribed incorrectly, and there is no way to tell which part. In the paragraph on the multiple correlation, maximum oxygen uptake appears in place of balance, a sign of text carried over from another paper.

With 13 people, correlations all between 0.87 and 0.94, even between tests of different things, point to a common factor: age, body mass, years of shooting or simply general fitness. None of these was measured or controlled. A correlation, in any case, does not show that training a quality raises the score. The journal is flagged in the registry as having questionable editorial standards.

The study gives no guidance on what to train. That the fitter archers in a group of 13 also shoot better is plausible, but these data cannot separate the effect of fitness from that of experience: an archer who has been shooting for longer is usually better conditioned as well. The four tests also move together, so there is no way to say whether arm endurance matters more than balance. With a descriptive table that does not add up and no test protocols, the headline figure, the R of 0.921, does not stand comparison with more careful studies of strength in archers.