Figure 8.

Distribution of displacement hysteresis coefficient S_hyster. The ratio R(t) / R(0) displays a hysteretic character over a breathing cycle, and a measure of this hysteresis is defined as the ratio S_hyster = A_hyster / A_total. a) Case without muscle content within the ring (m = 0): the hysteretic loops are clockwise (considered positive) since displacements are larger during inspiration, and diminish toward the external boundary; b) Case m = 1: the overall hysteretic muscle characteristic is dominant and the surface A_hyster is negative (see Fig. 7b).