As most people know, there is a group of four muscles in the shoulder known as the rotator cuff. One of the main tasks of the rotator cuff is to help stabilize the glenohumeral joint throughout arm elevation. The rotator cuff basically counterbalance the effects of the big strong guys (lats, deltoids, pecs) to allow for proper shoulder mechanics and to prevent the ball from coming out of the socket. What people are less aware of is there are smaller muscles in the hip joint (deep lateral rotators) which also help to provide stability and counterbalance to the big strong guys (glutes). The hip, like the shoulder, is a ball and socket joint which allows for a large amount of multidirectional motion. In order to keep the ball in the socket, this type of joint requires use of muscle tissue and with a labrum.
The muscles that we will be looking at today include the piriformis, gemellus superior, obturator internus, gemellus, inferior, obturator externus, and quadrates femoris, and the are collectively known as the deep lateral rotators of the hip. Now these muscles in the hip are certainly not an exact replica of the rotator cuff in the shoulder, because they are anatomically different and the hip is more inherently stable due to being a weight bearing joint, but they do have some underlying functional similarities. The main actions of the muscles are lateral/external rotation of the hip, but their line of pull also pulls the ball of the femur into the acetabulum. These muscles do not tend to act individually, but will act as a functional unit to stabilize the hip by creating a compressive force in the joint throughout motion. This is important because an increase in joint translation or gliding can lead to other pathology, such as a hip labral tear. Rotational muscles of the hip are also being looked at more and more as large dynamic stabilizing influence on the kinetic chain, primarily in the frontal and transverse planes, which may play a large factor in patellofemoral pain. There may also be some relation between hip rotation strength and lower back pain
Exercising these muscles can be accomplished in a variety of ways, but the important thing to remember is the more the hip is flexed, the more likely you are to “isolate” the deep lateral rotators, as opposed to the bigger movers, such as the gluteus medius and gluteus maximus. Just remember you cannot selectively isolate these muscles, you can just hope to maximize recruitment. One group of exercises that may be beneficial include clam shells with the hips flexed in different positions. Another good exercise to get baseline strength is seated hip external rotation with the hip flexed to 90 degrees, both with and without outside resitance.
Another method to target the deep rotators is to challenge them with other functional movements. My favorite method to accomplish this is to use a band round the knees/thighs while squatting or using a leg press.
Hopefully this has been a somewhat helpful refresher of hip anatomy, and will help you think outside the box when addressing hip pathology.