Weight Training with Combined ACL and MCL Tears in a 16-Year-Old
A 16-year-old with combined ACL and MCL tears can perform modified weight training under supervision, but must avoid exercises that create high anterior cruciate ligament forces, particularly open kinetic chain quadriceps exercises and movements from 30 degrees of flexion to full extension. 1
Initial Management Considerations
The MCL typically heals with conservative management, while ACL treatment decisions depend on activity goals and functional instability. 1 For a 16-year-old athlete, the evidence supports early ACL reconstruction to provide knee stability and protect menisci from subsequent injury, as younger patients have higher activity demands. 1
However, weight training can begin immediately even before surgical intervention, with critical modifications:
Safe Weight Training Parameters
Permitted Exercises (Low ACL Force)
Closed kinetic chain exercises are strongly preferred over open kinetic chain movements, as they generate lower ACL forces and better protect healing tissues. 2, 3
Hamstring-focused exercises should be emphasized over quadriceps work, as balanced hamstring-quadriceps forces are necessary for proper knee kinematics and ACL protection. 4
Upper body weight training is unrestricted and should be maintained to prevent deconditioning. 4
Core stability exercises are recommended as they improve gait and subjective knee function without increasing injury risk. 2
Restricted Exercises (High ACL Force)
Avoid open kinetic chain quadriceps exercises (leg extensions), particularly from 90-45 degrees of flexion, as these create large ACL forces. 3, 4
Do not push weight from 30 degrees of flexion into full extension, as this movement pattern generates maximum ACL strain despite protecting the patellofemoral joint. 4
No jumping, plyometrics, or explosive movements until cleared by rehabilitation milestones, typically not before 24 weeks post-injury or post-surgery. 4
Specific Exercise Modifications
If performing quadriceps strengthening:
- Use low weight through full range of motion rather than heavy weight through partial range. 4
- Initiate isometric quadriceps exercises when pain-free. 3
- Progress to closed kinetic chain exercises (squats, leg press) with controlled depth and load. 2
Recommended strength training approach:
- Prioritize hamstring curls, Romanian deadlifts, and posterior chain work. 4
- Include bilateral leg press with limited range (avoiding terminal extension under load). 3
- Perform upper body compound movements (bench press, rows, overhead press) without restriction. 4
Critical Pitfalls to Avoid
The most common error is premature return to unrestricted weight training based on feeling "ready" rather than objective criteria. 5 Even when pain-free and range of motion is restored, ligament healing strength remains low for months. 4
Time-based restrictions cannot be substituted with functional parameters alone. The classic parameters of return to play (pain-free, full ROM, strength) do not indicate adequate ligament healing and must not replace time restraints. 4
For skeletally immature patients (which may include a 16-year-old), growth plate considerations require surgical consultation before aggressive loading, though the evidence specifically excluded children under 16 years in major rehabilitation guidelines. 1
Supervision Requirements
Supervised rehabilitation is appropriate and rated as suitable treatment for ACL-deficient patients, particularly when combined with activity modification. 1 A structured program—whether home-based or in-person—produces similar effectiveness for strength and function outcomes. 6
Neuromuscular training should be combined with strength training rather than performed in isolation, as motor control and strength work are complementary and neither can replace the other. 2
Timeline Expectations
If proceeding non-operatively with conservative management:
- Weeks 0-12: Maximum protection phase with controlled forces. 4
- Weeks 12-24: Moderate protection with gradual load progression. 4
- Weeks 24-48: Minimum protection with continued restrictions on high-risk activities. 4
If proceeding with ACL reconstruction:
- Postoperative day 1: Begin isometric quadriceps exercises. 3
- Weeks 0-4: Closed kinetic chain exercises only, no added weight. 3
- Week 4+: May begin open kinetic chain (90-45°) but no extra weight for 12 weeks. 3
- Return to unrestricted sport typically requires 9-12 months and objective criteria including limb symmetry index >90% for strength. 3, 7
The key principle is that weight training is not contraindicated, but exercise selection and loading parameters must be strictly controlled to protect healing ligaments while preventing muscle atrophy and deconditioning.