Dr. Farah Hameed recommends strengthening this one muscle to help prevent injuries in Prevention.com's article

What's the one muscle that most people neglect but is essential in protecting your muscle? According to Dr. Farah Hameed, that muscle is the gluteus medius, the muscle on the outside of the pelvis.

This gluteus medius and the other 2 gluteal muscles help stabilize the pelvis. Dr. Hameed advises the strengthening of this muscle due to the fact that its weakness can lead to stress on the knee, foot, and ankle resulting in injuries. 

The article goes over 3 exercises that you can do to help target the gluteus medius. To find out what those 3 exercises are, read the full article