“Use it or lose it” is the ultimate cliché for the muscles of your body. Anyone who has had a significant injury requiring rest from exercise has experienced it. You can see it in the discrepancy between calf muscles in someone who has had a short leg cast or fracture boot for 4-6 weeks. The same goes for the muscles of the forearm after a fractured wrist requiring a short arm cast. And the most dramatic example, the quadriceps of an athlete following ACL repair.

We all know that after an injury like those mentioned, the patient requires a period of rehabilitation to regain strength and range of motion in the damaged body part. However, what happens to the rest of the body during the rest and rehabilitation of the injury?

Let’s take the example of a college baseball pitcher who breaks a bone in his foot at the start of the baseball season. He is placed in a boot for 6 weeks to let the bone heal. After the 6 weeks, x-rays look good and he is cleared to start physical therapy. His calf on the injured side is now much smaller than the other side, and his ankle is stiff from not moving for six weeks. The therapy focuses on correcting those issues, and he starts doing some light throwing on the field with teammates.

After about 4 weeks, the strength is back in his lower leg, the foot and ankle feel good and after 10 weeks away from the field, our pitcher is itching to go. He gets back on the mound feeling great, but after a few starts, he begins having shoulder pain and is diagnosed with rotator cuff tendinitis. Does our pitcher have bad luck, or something else?

Let’s look back at our timeline. Our pitcher was completely inactive for 6 weeks following the injury, then only worked on the foot and ankle for 4 weeks. That means for 10 weeks the muscles between his shoulders and knees have not been stressed other than basic day-to-day activity.

Studies show that muscles can lose up 25-30% of their strength after just 2 weeks of inactivity. Our pitcher had 10 weeks! That means those core muscles I talked about in my last blog just got weaker and weaker over those 10 weeks, leaving our pitcher relying solely on arm strength when her returned to the mound. Ask any trainer, therapist or sports doctor what happens to a pitcher with a weak core, and you’ll get the unanimous response of an injury to the throwing shoulder.

All athletes are eager to return to their respective sports following an injury. However, as medical providers, it is imperative to step back and look at the entire picture. We have to remember that the entire body has been limited by the injury, not just the injured body part. We have to work together to rehab and strengthen everything and make sure he or she is fully healthy to safely return to their sport of choice. This is one of the main reasons a good care team is so important for an athlete.