Muscle and tendon have an adaptive, symbiotic biomechanical relationship that is drastically altered following acute tendon injury. Such injuries, like Achilles tendon rupture (ATR), do not only lead to impairments in the resultant tendinous tissue, but also to irrecoverable atrophy in the connected muscle in series. As a result, a new relationship between muscle and tendon is established after ATR, leading to lasting functional deficits in the lower limb. It remains unclear how these develop, particularly since this imbalance may be influenced by the dependent relationship of the two tissues to each other. A further confounding factor is that tendon and muscle tissues adapt on different time scales in response to mechanical loading, such as those introduced during rehabilitation. Thus, it is warranted to perform assessments not only of the overall muscle-tendon unit, but also its constituent tissues. This presentation will discuss findings from both short-term and long-term follow-ups of ATR patients, with a focus on the recovery of gait and changes in the muscle-tendon unit tissues following ATR repair. Both the influence of the rehabilitation process and suggestions for future research directions will be additionally presented.