Maintaining muscle mass during an injury can be challenging but not impossible. Here are some strategies that might help:

1. **Nutrition:** Focus on adequate protein intake to support muscle repair and growth. Include sources like lean meats, poultry, fish, eggs, dairy, legumes, and nuts. Consider consulting a nutritionist or dietitian for a personalized plan.

2. **Adjust Your Training:** If your injury allows, try to modify your workouts to prevent muscle atrophy. For instance, focus on exercises that don't aggravate the injury. This might involve working other parts of your body or doing exercises that you can perform without risking further damage.

3. **Isometric Exercises:** Depending on the injury, isometric exercises (where the muscle contracts without changing length) might be safe and helpful in maintaining muscle strength without stressing the injured area. Always consult with a healthcare professional or physical therapist to ensure the exercises are safe for your specific injury.

4. **Physical Therapy:** If feasible, engage in physical therapy sessions tailored to your injury. Therapists can guide you through exercises that maintain muscle mass without worsening the injury.

5. **Rest and Recovery:** Allow your body to heal. Sometimes, resting the injured area is the best way to prevent further damage and promote recovery.

6. **Cross-Training:** If one part of your body is injured, focus on training other areas that aren’t affected. This helps maintain overall fitness and can indirectly support your recovery.

7. **Stay Positive:** Mental health matters too. Injuries can be frustrating, but maintaining a positive mindset can help you stay focused on recovery and prevent excessive stress, which can hinder muscle maintenance.

Remember, it's crucial to follow your doctor's or physical therapist's advice regarding exercise and recovery. Pushing too hard too soon can worsen the injury and delay your overall progress.