Answer:
They enhance movement of oxygen from the blood into the muscles.
Explanation:
Myoglobin and hemoglobin have the ability to bind oxygen. But myoglobin have higher affinity to binds oxygen so it can take away the oxygen from hemoglobin when they are in contact.
Hemoglobin will transport oxygen from the lung into all body parts. When hemoglobin passes muscle tissue, The exchange of oxygen will occurs from Hemoglobin to myoglobin (because of the higher affinity.) As the result, They enhance movement of oxygen from the blood into the muscles.