Researchers are trying to find out whether the use of low-intensity strength exercises during the 2 weeks before surgery, and while the blood flow to the leg is reduced, will improve the outcomes after surgery to repair an injured ligament of the knee.

Inclusion Criteria:

• Subjects must be between 13 and 40 years old
• Subjects must have been previously diagnosed with a tear of the anterior cruciate ligament in one of the lower extremities that requires surgical reconstruction
• Subjects must be able to understand study procedures and comply with them for the entire duration of the study
• Subjects must have normal contralateral limb strength

Exclusion Criteria:

• Subjects with any personal history of deep vein thrombosis or with such history in their immediate family
• Subjects who have any multi-ligamentous injuries to the knee that require modified post-operative unloading
• Subjects who have history of previous anterior cruciate ligament reconstructions in either the affected or unaffected leg
• Subjects with an inability or unwillingness of individual or legal guardian to give written informed consent