The wireless head impact sensor has been reported to underestimate rotational accelerations by 25%. As a result the impact rotational measurements should be assumed to have some form of error that is dependent on impact conditions and the measure of interest and the variability tested[xxix]. It is unlikely that the wireless head impact sensor was tested under all of the activities seen in rugby union matches such as the rucks, mauls, lineouts and scrum situations and how these correlate to the laboratory conditions results. As such, the results presented in this study should be interpreted with some caution.