Injuries to the anterior cruciate ligament (ACL) are one of the most common knee injuries, with the majority occurring during non-contact manoeuvers such as side-stepping and single leg landing. Surgical intervention is generally required to restore stability to the tibiofemoral joint, unfortunately no perfect graft choice exists for reconstruction of the ACL, with all graft choices having potential advantages and disadvantages. The quadrupled hamstring autograft taken from the semitendinosus (ST) and gracilis (GR) muscles is a common choice for orthopaedic surgeons. However, harvest of the ST and GR tendons leads to post-operative donor muscle atrophy, as well as proximal retraction of the musculotendinous junction. This could in turn, have implications for tibiofemoral joint function, stability and loading. Thus, the overarching purpose of this thesis was to explore the morphological changes that occur to the donor muscles following tendon harvest and their biomechanical consequences.