The significantly smaller mean TrA thickness recorded in arelaxed state for those who most frequently experience ETAP isan interesting finding. Trunk muscle thickness may be relatedto training levels, but it is also dependent on the size (heightand weight) of the individual. Training specifically for abdomi-nal muscles was not recorded in this study, but there were nobetween-group differences on height or BMI. Men have signif-icantly larger muscle size in the abdominal muscles (measuredby ultrasound); however, there were no significant differencesbetween our groups for gender. Although our groups did haveage differences, with an older mean age for the group that neverexperienced ETAP, age has been shown to correlate poorly withmuscle thickness.With this in mind it is tempting to speculatethat those with thinner relaxed TrA may activate this muscleless when exercising and this is linked to lower training volumesand the higher prevalence of ETAP. Clearly the impact of trainingand activation during exercise of the abdominal muscles and thefrequency of ETAP remains an issue for further research.