Fig. 5

Mechanical and viscoelastic properties of the anterior cruciate ligament (ACL) of control and post-trauma mouse knee joints. A, B Average stress-strain and tangent modulus-stress curves showed a decrease in stiffness at all strain rates for the post-trauma ACLs compared to healthy ACLs. C Normalised tangent modulus-stress curves (normalised from the 0.1%/s strain rate curve) compared differences in 1%/s and 10%/s strain rates, which were statistically significant in the control ACLs (p < 0.01) but not in the post-trauma ACLs (0 = 0.07), suggesting a lack of strain rate sensitivity in the post-trauma ACL. D Stress-relaxation curves showed lower normalised stress in the post-trauma ACLs. E Hysteresis curves at different strain rates showed no statistical difference between control and post-trauma (0.1%/s: p = 0.09, 1%/s: p = 0.08, 10%/s: p = 0.88). F Ultimate load at failure showed no statistical difference between control and post-trauma ACLs. Control = black, Post-trauma = red. Post-trauma ACLs are from + 6 weeks post-trauma