Fig. 2

Mean frequency of strain events reported during the four phases of the operations. Note: x-axis: 1 = Phase 1, before incision, 2 = Phase 2, begin (first third of the operation), 3 = Phase 3, middle (middle third of the operation), 4 = Phase 4, end (last third of the operation); y-axis: scale representing mean frequency of strain episodes reported by the participants