Force line in recurve archers: Ahmad 2025 study

Seven recurve archers from a Malaysian university campus, all right-handed and with at least two years of practice, were filmed to measure the angle of the drawing arm's force line, then compared by sex. There is no difference between the two groups in the angle: a mean of 39.2 degrees in the men, with a standard deviation of 1.71, against 42.1 in the women, with a standard deviation of 11.1 (t = 0.433, p = 0.683). Nor does the score at 10 metres separate the groups (p = 0.066). Between angle and score the correlation is negative and moderate, meaning that the archers with a more open angle tended to score less, but across seven archers it does not reach significance: r = -0.533 with p = 0.218.

There is a problem with the numbers. The score table reports the same means and the same standard deviations as the angle table, 39.2 plus or minus 1.71 for the men and 42.1 plus or minus 11.1 for the women, with a different t value. As printed, the two groups' scores cannot be read: all that is left is the p value and the direction of the difference. The authors' conclusions, that sex does not affect alignment and that alignment does affect performance, therefore rest on one table and one non-significant correlation.

The footage was taken with a digital video camera and analysed in Kinovea, a free motion analysis programme, with reflective markers at the wrist, elbow, shoulder and sternum. The score was collected at 10 metres on a 122 cm target face, with points assigned according to how close each arrow fell to the centre. The analysis is descriptive, with independent samples t tests between men and women and a Pearson correlation between angle and score.

The text is a two-page contribution to the proceedings of a postgraduate colloquium at Universiti Teknologi MARA, and the method takes up a single paragraph. It does not state how many arrows were shot, or how many of the archers were men and how many women (the degrees of freedom, 5, say only that the two groups together make seven), where the camera stood and at how many frames per second it recorded, how many shots were digitised, which three points defined the angle that was measured, or what bows and draw weights the archers used. The unit of the angle is missing from the tables too: the 39.2 and the 42.1 are degrees because the text says so.

This is a short record because the study is short: seven archers from one university team, no comparison group, a single session, and the authors themselves call it a case study. With seven people the confidence interval around an r of -0.533 takes in everything from a strong relationship to none at all, and a p of 0.066 on the score says neither that there is a difference nor that there is not.

The two identical tables remain the more serious problem: the scores reported are the angle figures. The angle is measured in two dimensions from a single camera, so it describes the plane of filming rather than the orientation of the arm in space, and it comes from marker-based software with no calibration described. The idea that a more open angle tires the muscles and leads to injury is taken from the literature the authors cite, not measured here: there are no measures of fatigue, pain or effort. Among the references is an article from a popular magazine whose address still carries the tracking parameter of a session with a conversational assistant, and another has a truncated DOI, which says something about how far the citations were checked.

For an archer, nothing changes. The idea that an elbow in line with the arrow costs less effort is a coaching one, older than this study, and it is not tested here: fatigue is not measured, nobody is followed over time, and the link with the score stays within the margin of chance. As for the score, seven archers at 10 metres on a 122 cm face leave very little room: at that distance, on that face, archers of quite different levels end up bunched near the centre.

What remains is the procedure. A camera, four markers on bony landmarks and Kinovea are enough to obtain the angle of the drawing arm, which is within reach of a club, provided the camera position is fixed and the same plane is filmed every time. The other finding, taken for what it is, is that in this group the men's angle and the women's could not be told apart.