Peak expiratory flow in archers: Thakare 2015 study

The study measures peak expiratory flow, the maximum speed at which a person can blow air out in a forced breath, in 160 archers aged 18 to 25 taking part in the Indian inter-university championship at Kurukshetra in November 2014. The archers were grouped by bow: 62 shooting the traditional Indian bow, 56 recurve and 42 compound. The means are 492.5 litres per minute (standard deviation 32.95) for the Indian bow, 496.43 (37.55) for recurve and 508.33 (30.28) for compound.

The author concludes that all the archers had higher values than an ordinary person, that the compound archers had the highest values of the three groups, and that the difference comes from the equipment. According to the paper these archers trained three to four hours a day, six days a week.

Measurements were taken with a Wright peak flow metre between 10 and 11 in the morning on competition days, after the archers had been shown how to use it: each made three attempts and the best was kept. Age, weight and height were also recorded. The Indian bow archers averaged 160.5 cm and 61.7 kg, the recurve archers 176.7 cm and 68.2 kg, and the compound archers 163.3 cm and 58.4 kg. The paper runs to two pages and reports no statistical test: the three groups are compared by looking at the means.

The differences between groups are small compared with the spread within each group: 16 litres per minute between compound and Indian bow, with standard deviations between 30 and 38. Without a statistical test there is no saying they are anything more than chance. Peak flow depends heavily on height, age and sex; the archers' sex is not reported and the groups differed in height (the compound group was 13 cm shorter than the recurve group, yet had the highest values), so the comparisons are not like for like.

The comparison with ordinary people rests on no control group and on no reference values presented in the results. Some means and standard deviations in the text also differ from the table (508.5 instead of 508.33, 496.5 instead of 496.43): this record uses the table. The journal is flagged in the registry as a venue with questionable editorial standards.

For archers the study changes little. It shows that a group of Indian university archers who trained for many hours had a peak expiratory flow of around 500 litres per minute, with no clear difference between Indian bow, recurve and compound. It does not show that archery improves lung function, since there is neither a comparison group nor a measurement before and after a period of shooting, and it does not show that the type of bow changes the lungs of the person using it.

Anyone working on breathing in the shot will find no link with performance here, because the archers' scores were not collected.