Grip, balance and young archers: Prasetyo 2023 study

Sixty young Indonesian archers aged 12 and 13, 34 boys and 26 girls, registered at the archery centre of Sleman Regency in the Yogyakarta area, were measured once on three things: grip strength with a dynamometer, static balance with the stork balance stand test, and the score over 36 arrows at 15 metres on an 80-centimetre target face, for a maximum of 360 points.

Grip strength correlates with the score at r = 0.446 (p = 0.000) and static balance at r = 0.262 (p = 0.043). Combined in a multiple correlation, the two measures give R = 0.480, with p = 0.001 in the abstract and p = 0.002 in the table. Translated into variance explained, these values are about 20% for grip, 7% for balance and 23% for the two together. The authors describe both correlations as moderate.

The rest of the data is descriptive and by category rather than in units. On grip, 30 boys out of 34 and 16 girls out of 26 fall into the lowest category of the scale the authors use; no boy reaches the highest category, against two girls. The scores spread across the whole range: nine archers out of sixty fall between 331 and 360 points, seven between 171 and 210. Neither means nor standard deviations are reported for the grip and balance values, and there are no regression coefficients, no variance explained and no scatter plots.

The study is descriptive and cross-sectional, collected at the Sleman Regency shooting field in January 2022. The sample was chosen by purposive sampling on five criteria: being a registered and active archer in Sleman, being physically and mentally healthy, being 12 or 13 years old, agreeing to be tested and having already shot at 15 metres.

The independent variables are grip strength and body balance, the dependent variable is the score at 15 metres. Grip is measured with a hand dynamometer; the paper does not say which hand, how many attempts, in what position or in which unit. Balance is the stork balance stand test, timed, that is the time spent balancing on the ball of one foot with the other foot resting against the inner knee. The shooting score is the total over 36 arrows at 15 metres on an 80-centimetre target face, with each arrow worth 1 to 10 points.

The authors report two reference scales taken from the literature, one for grip and one for balance, and use them to place each archer in a category. The analysis is a Pearson correlation between each variable and the score, plus a multiple correlation of the two together, in SPSS version 26. Boys and girls are analysed together as a single group. No other anthropometric or maturation measures are reported, nor the draw weights of the bows, nor the discipline.

The main problem is age. At 12 and 13, grip strength depends largely on height, mass and stage of maturation, and so does the ability to handle a bow: the more developed hold the bow steadier and score more. The study does not measure height, weight or maturation, so the correlation between grip and score may largely reflect how far each child has grown rather than hand strength as a trainable quality. This is why an r of 0.446 in a sample of 12 and 13 year olds says less than it appears to.

Boys and girls are analysed together. At that age grip differs between the sexes, and in the authors' own data the distribution by category differs, so sex remains an untreated confounder: part of the correlation may come from there. There is no analysis by sex, no adjustment and no model holding more variables together than the two.

Almost nothing of the measured values is left to check. Neither grip nor balance has means, standard deviations or units in the text: there are only the categories. The multiple regression is reported as a single R coefficient, with no per-variable coefficients, no variance explained and no confidence intervals, so there is no way to know how much each of the two measures weighs net of the other. The p-value of the multiple correlation is 0.001 in the abstract and 0.002 in the table.

The two reference scales, as printed, do not hold together. The grip scale leaves a gap between 31.2 and 32.2 for boys, and for girls puts the lowest category above 49 and the highest between 35 and 43, that is the other way round. The descriptive tables carry figures that do not add up: the balance percentages for boys are copied from those for grip (88% on 11 archers out of 34), and the female total is printed as 20 in two tables out of three, while the frequencies listed sum to 26. The two paragraphs introducing the balance tables also repeat the grip description. These are editorial rather than data errors, but they leave a reader little room to check.

What remains is a cross-sectional design, measured once, at a single centre and in a single age band, with 36 arrows at 15 metres on an 80-centimetre face: a short test, at a distance and on a target that match no competition format. A correlation says nothing about the direction of the relationship, and the later part of the discussion proposes grip-strengthening exercises, bench press, pull-ups and planks, which come not from these data but from the literature cited.

For anyone coaching youngsters, the figure to keep is the weight of these correlations, not the fact that they exist. Grip explains about a fifth of the variation in scores and static balance less than a tenth; together they reach about a quarter. Three quarters of what separates a 12 year old scoring 340 from one scoring 200 lies elsewhere: in technique, in equipment suited to their size, in arrows shot.

Single-leg balance in particular barely holds: r = 0.262 at p = 0.043 on sixty youngsters is the kind of result a slightly different sample would not find again. It is worth noting that in other studies on archers the same test comes out unassociated with the score, so this is not settled ground.

There is also a more useful reading of the grip correlation. At twelve and thirteen, whoever has the stronger hand is usually also the more grown, and a bigger child handles a bow that is too much for the others. Read that way, the correlation says something about equipment rather than about strength: a draw weight above what a child can hold shows up in the score. The study measured neither height nor draw weight, so this is a reading rather than a finding, but it is consistent with its own numbers.

The most telling descriptive figure is that most of these youngsters, 30 boys out of 34, fall into the lowest grip category of the scale the authors use, while the scores cover the whole range, from 171 to 360. With a grip classed as insufficient, some were scoring over 330 out of 360: the strength category on its own does not say how a child shoots.