Fitness tests in young archers: Musa 2016 study

Seventeen young Malaysian archers aged 13 to 19 (mean 16.9), boys and girls from a development programme in the state of Terengganu, completed a battery of physical tests. Six variables enter the analysis: age, body mass index, sit and reach, push-ups and sit-ups in one minute, and maximal oxygen uptake estimated from a shuttle run. On these six the authors ran a principal components analysis, a technique that groups variables which tend to move together.

Two components emerged. The first explains 43.39% of the variability and brings together oxygen uptake (loading 0.78), sit-ups (0.75), body mass index (-0.71) and age (-0.69): those who ran better also did more sit-ups and tended to be younger and to have a lower body mass index. The second explains 20.97% and brings together push-ups (0.76) and sit and reach (0.75). The authors call the first endurance and the second upper body strength, and conclude that these are the essential physical qualities for archery. The shooting score, however, is not part of the analysis.

Sit-ups were counted over 60 seconds with knees bent, one attempt only; push-ups over one minute, also one attempt. Oxygen uptake was estimated with a formula from the level reached in the 20 metre shuttle run, not measured. The sit and reach allowed two attempts with the better one kept; in the results it becomes the V-sit and reach. Height, sitting height, skinfolds and girths were also taken following the ISAK protocol, but only body mass index enters the analysis. The principal components analysis keeps components with an eigenvalue above 1 (2.60 and 1.26), rotates them with varimax and treats loadings above 0.65 in absolute value as relevant; sampling adequacy was checked with the KMO index, which was 0.70.

The limitation that matters most is that the analysis contains no shooting measure at all. The abstract says scores were recorded, but neither the numbers nor any use of them appear in the text. A principal components analysis run only on physical variables shows how those variables group together in these seventeen youngsters, not which of them matter for shooting well: the conclusion about the qualities essential for archery does not come from the data.

There are technical problems as well. Seventeen people is a small sample for this kind of analysis, which gives unstable groupings with samples that size. The KMO index is read as proof that the variables are not collinear, which is not what it measures. The percentages of variability in the text (37.11 and 27.25%) do not match those in the table (43.39 and 20.97%), although the total is the same. The sit and reach is a flexibility test yet ends up labelled as upper body strength, and the text refers to seven variables in a component that has four. The paper does not say how many were boys and how many girls, what bows they used, or what being measured repeatedly means. Some of the citations for the methods point to unrelated studies, and the registry flags the journal for doubtful editorial standards.

For an archer or a coach the study changes nothing. It links no physical quality to score, so it cannot point to what preparation should focus on, even though its conclusions claim to. What remains is a description: in these young archers, those who did better in the shuttle run also did more sit-ups, and those who did more push-ups were also more flexible. These are relationships between general fitness tests, measured in seventeen youngsters, and they say nothing specific about shooting.