Yips in kyudo, prevalence and causes: Nishio 2021

A group of Japanese neurologists asked members of the kyudo clubs at the medical schools of Gifu and Kumamoto whether they had ever suffered from one of the four shooting problems that kyudo tradition has long recognised: hayake, the release that goes before the intended moment; motare, the release that will not come when wanted, with an aim that drags on far too long; biku, an involuntary jerk of the arm as if to shoot, without the arrow leaving; and yusuri, a tremor of the upper arm or forearm during the draw and aim.

Of 70 archers, 65 replied, and 41 (63.1%) said they had suffered at least one. Hayake was by far the most common: 35 of the 41, 26 of them with no other problem. Motare appeared in 3 people, always on its own; biku never appeared on its own, and in those with more than one problem it almost always came after hayake. The problem had been overcome by 12 of the 35 with hayake, 2 of the 3 with motare, 1 of the 7 with biku and 5 of the 7 with yusuri.

Comparing the 41 archers with a problem against the 17 without, the former were more often male, older, had been shooting for longer (5.0 against 2.5 years), had a higher hit rate (36.2% against 17.5%), stronger bows (13.4 against 11.2 kg) and had more often been injured while shooting. With everything entered together in one model, only experience remained: each extra year of practice went with roughly 2.7 times the odds of having had a problem (confidence interval 1.011 to 7.084).

The questionnaire, anonymous and with written consent, was handed out in December 2018 to the 70 members of the two clubs (44 at Gifu, 26 at Kumamoto). It asked about sex, age, height, weight, dominant hand, difference in arm size, years of practice, arrows shot per month, tiredness at the end of training, hit rate, bow strength in kilograms, dan grade, injuries during practice, and finally whether any of the problems had appeared, which ones, and whether they had been overcome. Those who had suffered one also described what it felt like.

A problem counted as present if the archer believed they had had it: nobody was observed shooting or examined. Mean age was 20.7 years, mean experience 4.0 years and mean grade 1.2 dan. For the comparison the 7 who could not say whether they had had a problem were left out, leaving 58 people; the variables that came out significant one at a time were then entered into a logistic regression.

The 63.1% figure is the one reported by medical students from just two university clubs, of modest level, answering from memory about their own shooting history: the definition rests entirely on the respondent's judgement, and the figure cannot be extended to kyudo in general or to Olympic-style archery. Calculated on the 58 who could answer, the same share rises to 70.7%.

The main finding is partly a foregone conclusion, as the authors themselves acknowledge: the question asked whether a problem had ever appeared, and the more years one shoots, the more chances there are. The confidence interval starts at 1.011, so the effect is only just over the line, with seven variables for 58 people. The link with a higher hit rate points the same way: those who have been shooting longer also shoot better. The figures for biku and yusuri differ between the table (8 each) and the text (7 each). The idea that motare is a task-specific focal dystonia and hayake mainly a mental problem is the authors' hypothesis, built on three cases in the first instance and on personal accounts in the second, with no electromyography or examination.

For an Olympic-style archer the study matters mainly because it describes precisely a family of problems that in archery goes by the name of target panic. The authors themselves liken hayake to the early release and motare to being unable to release, and their data show that the two forms behave very differently: the first is common and often comes with other problems, the second is rare and stands alone. Keeping them apart, rather than speaking of a single problem, is the study's most useful contribution.

The second point concerns who is affected: more than the beginners, it was the archers with more years of practice and better results, who had also had more time to run into the problem; two thirds of those with hayake had not yet overcome it. The study does not say where these problems come from or how they resolve: the accounts it collected, such as hayake improving when the instructor reminds the archer not to release early, or in training without pressure, are individual reports, not evidence of a remedy.