They are able to take up and store more oxygen in their muscles
Explanation:
According to Oxford dictionary, myoglobin is ''a red protein containing haem, which carries and stores oxygen in muscle cells. It is structurally similar to a subunit of haemoglobin.''
The fact that Tibetans have a high level of myoglobin implies that they are able to take up and store more oxygen in their muscles since myoglobin is involved in storage of oxygen in muscle cells. Hence elevated levels of myoglobins enables the muscle cells to work more effectively.
