This dissertation represents a series of clinical investigations that provide critical insight into the development of rehabilitation approaches to combat the ubiquitous quadriceps weakness that occurs following anterior cruciate ligament injury. As quadriceps weakness accelerates joint degeneration and leads to a lower quality of life, identifying therapies capable of restoring strength is essential to preserving long-term health. With the above in mind, aim one examined if eccentric cross-education, whereby the uninvolved limb is exercised, is capable of improving quadriceps function in the unexercised limb. It was found that exercising with eccentric contractions resulted in mode and velocity specific strength gains in the unexercised limb, as well as a trend toward improvement in quadriceps neural activity. As a reduction in neural activity of the quadriceps (i.e. quadriceps activation failure [QAF]) is thought to be a primary cause of weakness, rehabilitation programs may be able to utilize this type of therapy to enhance neural activity and quadriceps strength. Examining the role of QAF further, aim two investigated the relationship between pre-operative QAF and post-operative QAF and strength. It was found that pre-operative QAF was positively related to the recovery of post-operative QAF, but not strength. Hence, therapies that target pre-operative QAF should help to improve the recovery of neural activity post-reconstruction. Further, clinicians should continue to focus on maximizing strength before surgery. Lastly, aim three was conducted to determine the effectiveness of a combined neuromuscular electrical stimulation (NMES) and eccentric exercise intervention to improve the recovery of quadriceps strength and knee mechanics post-reconstruction. It was found that eccentric exercise was capable of restoring levels of quadriceps activation and strength that were similar to those of healthy adults and better than NMES alone. Whereas individuals that received the combined NMES and eccentrics intervention demonstrated the best recovery of knee mechanics. Taken together, these results indicate that eccentric exercise is an effective therapy to improve quadriceps neural activity and strength, though a longer intervention may be needed to positively influence movement. Additionally, interventions that are capable of minimizing pre-operative QAF should be employed to improve the recovery of post-operative quadriceps function.