A randomized clinical trial involving 30 individuals submitted to ACL reconstruction will be conducted.

Participants will be randomized into: Group I, submitted to a muscular rehabilitation program based on eccentric isokinetic exercise; and Group II, submitted to a muscular rehabilitation program based on eccentric isotonic exercise. Concomitantly with the muscular rehabilitation protocols, individuals will undergo the same physiotherapeutic protocol with analgesia, edema reduction, range of motion, proprioception and functionality goals. Muscle rehabilitation programs based on eccentric isotonic and isokinetic exercise will begin 45 days after ACL reconstruction. The programs will last six weeks, with training frequency of two sessions per week, separated by a minimum interval of 72 hours.

Inclusion Criteria:

• Young adults aged between 18 and 40 years;
• Recreational athletes;
• Unilateral ACL injury;
• Presence of total or partial rupture of unilateral ACL within 90 days after injury;
• Male subjects;
• Classification of body mass index up to pre-obese (25.0 - 29.9 kg / m2);
• Not undergoing any strength training program for the lower limbs in the six months prior to the study.
• Acceptance of individuals in participating in the procedures proposed by the research.

Exclusion Criteria:

• Recidivism in ligament injuries;
• Associated ligament and / or meniscal lesions;
• Previous history (<6 months) of musculoskeletal lesions in the thigh;
• Patellar tendinopathy;
• Patellofemoral pain syndrome;
• Respiratory or cardiovascular conditions that limit the performance of exercises;
• Users of dietary supplements or anabolic steroids