Technology in archery training: Chalkley 2016 poster

A poster from the Queensland Academy of Sport and the Australian Catholic University describes a test with elite Australian archers preparing for the Rio 2016 Olympic Games. The archers shot 12 arrows at 70 metres while standing on a mat that records the centre of pressure under the feet, once on the ground as in a normal training session and once on a raised platform built to resemble the one expected in Rio.

On the platform, sway under the left foot increased both sideways (p = 0.027) and front to back (p = 0.001), while the right foot did not change. For the centre of pressure of both feet together, only front-to-back sway increased (p = 0.017). The poster gives p values but not the means, the number of archers or the units; a bar chart shows higher values on the platform for all six measures, with the largest gap for the left foot front to back.

The mat was a Tekscan Sports Balance Analyzer, a thin layer of pressure sensors that the archer stands on; the poster's photos show it on the grass of an outdoor range and then on top of a dark raised platform. Custom software split centre of pressure sway into two directions, mediolateral and anteroposterior, for the left foot, the right foot and both together.

The two conditions were compared with a series of independent-samples t-tests. The poster does not say how many archers took part, their sex, how high the platform was, in which order the two conditions were shot, or whether scores were recorded.

This is a poster, a one-page summary without the underlying data: the number of archers, the means, the spread and the unit of sway are all unknown. The same people shot in both conditions, yet the comparison used tests for independent groups, which ignore that. If the order was always the same, ground first and platform second, fatigue or changing conditions during the day could account for part of the difference.

The text is also not fully consistent: the results report an increase in both directions for the left foot, while the conclusions mention an increase only front to back. Nothing links sway to score, and the authors list that link as something still to be studied.

The study suggests that a raised platform, like those built for the finals of major events, changes how an elite archer balances while shooting: centre of pressure sway increases, especially under the left foot. The authors conclude that archers should be measured in competition conditions and that training should reproduce them, so that the archer knows in advance how their stance changes.

It does not say how much sway increases, or whether it costs points. For anyone preparing for a final on a platform it is a hint in favour of getting used to the surface beforehand, not a measure of its effect on score.