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Chapter 364rTR in the ACL-deficient knees compared to uninjured contralateral knees during a wide based squat.32 This is in accordance with our findings. These findings emphasise the influence of time since injury on knee kinematics after ACL injury. In the acute setting, subjects exhibit different jumping strategies during activities (protective secondary to recent trauma) than weeks later. Weeks later, the secondary stabilizers of the knee may have stretched due to the altered mechanical load in the absence of the ACL. This may lead to an alteration of kinematics of the knee with the passage of time.Our study provides additional information for the debate on rTR due to a new measurement moment, namely in the acute phase after an ACL rupture. This also puts the post-operative measurements in a different light. Ristanis and Tsarouhas demonstrated that, after ACLR, rTR is smaller compared to contralateral-intact knees. 36,42,43This has been attributed to overconstrainment of the graft.31 It is questionable whether the reduced rTR post-operatively can be attributed to overtightening of the graft, as a smaller rTR was also found in ACL-deficient knees before ACLR (and even smaller compared to post-ACLR). Again, perhaps altered landing strategy, altered muscular contraction patterns and fear of re-injury should be taken into account more. Also, it has been shown in dogs that intact sensory nerves around the knee, probably by influencing protective muscular reflexes, play an important role in preventing the acutely unstable knee from rapid breakdown.34 Our study may indicate that these strategies have already started at the initial evaluation within 3 months after injury and are indelible by one year after reconstruction.Secondly, our study differs from previous research in terms of the used functional tasks: our subjects performed both low and high-demand functional tasks as opposed to previously reported low-to-moderatedemand functional tasks. Our results of rTR during level walking (low demanding) are comparable to earlier reports, both pre- and postoperatively.4 The rTR has not been previously measured using a motion capture system while the subjects were performing a SLHD or a sidejump. A hop test is a complex, high-demand task in which a lot of force is generated in the knee, and can also induce fear of injury. As seen in Mark Zee.indd 64 03-01-2024 08:56