Fig. 7

A Stress relaxation measured during a five-minute hold to examine viscoelastic tissue behavior. B Average ± standard deviation of the stress relaxation percentages based on treatment, region, and orientation. Elastase treatment resulted in significant decreases in stress relaxation across all samples, while collagenase treatment did not exhibit such a uniform response. Circumferential stress relaxation was significantly higher than its axial counterpart in the bronchial regions regardless of treatment