The position sense acuity was estimated based on the magnitude of shoulder repositioning error, the direction of error and the variability in the performance.
The MAPE is a summarizing measure to express the error during a certain period of time and ignores the direction of error.
However, the results indicated that the direction of error was significantly different between men and women, and men's performance tended to be significantly more variable than that of women.
It is not very clear why the direction of error was different in our experiment, but one possible reason could be the different strategies that men and women employ during movement tasks.
Further, because the direction of error points towards underestimation of change in high-rate short-duration behaviours, such as the ones typically observed in short-burst quick-scene changes in music videos, we aimed to reduce this by using a very short 10-second interval duration.
Such a difference in the direction of error has also been reported by Emery and Cote [ 26], where the authors found that during a reaching task after muscle fatigue, women tended to systematically make errors that were more anterior and inferior of the target, different from errors made by men.
The results also indicated a significant effect of sex on the direction of error (constant error) as women tended to mostly overestimate the target (81 % of the time), whereas men tended to both overestimate (55%% of the time) and underestimate (45%% of the time) the target (2.28° vs. 0.47° respectively, F 1, 78) = 8.0, p = 0.006, observed power = 0.79).
However, the analysis of the direction of error (constant error) showed a significant difference between the sexes, as women tended to mostly overestimate the target, whereas men tended to both overestimate and underestimate the target (p-value ≤ 0.01, observed power = 0.79).
The analysis of the direction of error (constant error) showed a significant difference between all three shoulder ranges for both men and women (F 2, 78) = 17.07, p < 0.001, observed power = 0.99) (Table 1), but no significant interaction between sex and shoulder ranges.
A total of 21 comparisons were performed to assess the number of errors, the weight of errors (ie, the volume difference between test and reference stimuli), and the direction of errors (ie, over- or underestimation of test stimulus).
