Concentration and EEG in archers: Feng 2023 study

Using a single-channel EEG headband, the study recorded two indices supplied by the manufacturer's software, "concentration" and "relaxation", on a scale of 0 to 100, in archers split into three groups of 10: excellent results, average results and arrows off the target. Mean concentration was 43.34 in the excellent group, 40.28 in the average group and 48.81 in the off-target group, so it was highest in those who shot worst. Relaxation was 59.39, 45.00 and 52.73: highest in the excellent group.

The arrow-by-arrow comparison points the same way. In the 51 arrows that landed in the 10, concentration was 44.23 and relaxation 58.16; in the 118 arrows below the 7 (below the 8 in the table heading) they were 41.19 and 45.42. The difference in relaxation is significant, the difference in concentration is not. In the conclusions the author writes that high relaxation goes with high scores, while the effect of concentration is not apparent.

The abstract says something else: it describes 20 traditional archers, a chi-square test and a positive correlation of both indices with performance. The body of the paper describes 30 male archers and an analysis of variance, and its data show no advantage for concentration.

According to the methods section, the participants were 30 male archers described as outstanding, split into the three groups "according to different training situations" with no explanation of the criterion. The instrument is NeuroSky's single-channel Circlet EEG system, with one sensor in the middle of the forehead and one on the earlobe, connected over Bluetooth to an IBM X200 laptop. The concentration and relaxation indices are computed by the manufacturer's software; according to the paper they usually fall between 40 and 60 in the general population.

The groups are compared with a one-way analysis of variance, with a threshold of p < 0.05. The paper also contains a mathematical model of how the point of impact deviates in response to small errors in the factors of the shot, but it is not used in the results. Shooting distance, bow type, how many arrows each archer shot and at which phase of the shot the indices were read are not reported. The paper states that no ethics approval was needed for this kind of study.

The inconsistencies are many. The number of archers is 20 in the abstract and 30 in the methods; the statistical test is a chi-square in the abstract and an analysis of variance in the methods; the percentages in the discussion do not match the tables (the excellent group's concentration is said to be 87% of the off-target group's, while the tables give 89%; relaxation is said to be 23% higher than in the average group, while the tables give 32%; relaxation on 10s is said to be 125.85% of that below the 7, while the tables give 128%). The author contributions section names three people other than the sole author and mentions surgery, and the reference list includes papers on tumour biology and on memorising the Qur'an.

The concentration and relaxation indices are proprietary algorithms in a consumer device, not measures of attention validated for archery. The 51 and 118 arrows come from different archers pooled together, so they are not independent observations, and the criterion used to form the groups is not described. The journal is flagged for questionable editorial standards, and these flaws are consistent with that flag.

For an archer this paper is not something to build on. Taken at face value, its data say that a higher "relaxation" index went with the better arrows and that the "concentration" measured by the device made no difference, the opposite of what the abstract announces. But the way it was written and reviewed does not allow much confidence even in that. Where the study is cited in support of training EEG headbands or concentration scores, there is no solid measurement of either here.