Fig. 1

Murine anterior cruciate ligament (ACL) imaging and mechanical testing setup. A The ACL was imaged with μCT using a contrast agent. ACL length and cross-sectional area (CSA) (yellow arrows) were measured. Scale bar is 1 mm. B Mechanical testing setup included custom-made clamps, which allowed for poly(methyl methacrylate) fixation of the femur and tibia at a 90° angle and for vertical alignment of the ACL. C Fixed samples were loaded into a dual column uniaxial machine (Instron) for mechanical testing of the ACL. D Mechanical testing protocol used for viscoelastic and material behaviour of the ACL included preconditioning cycles, strain rate testing at 0.1%/s, 1%/s and 10%/s strain rates, stress-relaxation loaded to 5% strain and ultimate load to failure at 1%/s until ACL rupture