Fig. 3

Loading steps in the current study: Pre-loading: sinusoidal tensile load changed from 5 to 20 N, with a frequency of 1 Hz; Incremental sub-failure cyclic loading: tensile load, with a rate of 25 N/sec to a peak value of 100, 150, 200, 250 and 300 N, then unloading and leaving the graft to be in rest for 60 s after each loading cycle; and finally loading graft to failure with a rate of 20 mm/s