The hip is a main driver of safety and function for the entire lower body. I really like the analogy comparing the hip to balancing a baseball bat on your finger tip. With no stability up chain, ie toward the top of the bat, it is quite the challenge to keep it steady. But, if we simply grab the bat from the top, it is much easier to control it all the way down chain. A similar concept applies to the hip and leg. Without proper function of the stabilizing muscles around the hip joint, standing on one leg becomes a challenging task, and other muscles need to work extra hard to stabilize the knee, ankle, and foot. But, when we bring the gluteus medius and minimus into play functioning at their highest level, we have greater control of everything below the hip because we have grabbed the leg by the top. Without getting into the prerequisites of range of motion at the hip, if we don’t have control and stability throughout, suboptimal situations are bound to surface. This is not to say we should neglect training of the knee ankle, and foot, but if we don’t have stability at the top of the chain we likely won’t be as effective in this training.
The gluteus medius is a muscle on the lateral side of the hip joint attaching the outer illium of the pelvis to the greater trochanter of the femur. The glute minimus sits deeper to the glute medius but attaches in these same areas. These muscles work together although the glute medius takes the brunt of the load due to its larger size and capability. Their main action when working from origin to insertion is abduction of the leg (moving it away from midline out to the side) while secondary actions aid in flexion, extension, internal, and external rotation at the hip. We can strengthen abduction of the hip through generic loading parameters but that won’t necessarily train the function of the glute med and min which is to stabilize the pelvis during gait and other dynamic activities.
When the foot is on the ground it is not abduction of the hip we should be concerned about. What we should be looking at is the ability to avoid hip drop as well as the ability to resist adduction and internal rotation at the hip. These movements when not addressed surface as knees falling inward toward each other (genu valum) and the hip shooting out laterally when walking or running (trandelenburg sign). This combination of attributes places a multitude of structures at risk of injury including those in the low back, hip, knee, ankle, and foot especially when placed under the immense stresses of sport, working out, or recreational activities. It negates our ability to properly absorb the external forces we may encounter such as ground impact, weight on our back, or an opponent contacting us. We need to train the hip and body to function with our feet on the ground in positions we may find ourselves in so that we can avoid these tendencies and have a training effect that will transfer to sport related activities.
One great example of an exercise that helps to train proper hip function is a single leg RDL. Moving through the primal hinge patter on one leg is a challenge and needs to be progressed towards, but gaining this ability transfers well to other activities as mentioned earlier. To make this movement even more effective you can load it unilaterally (holding a weight in only one hand) which will deviate the center of gravity even further calling on the hip stabilizing muscles to work even harder. All in all, clamshells, glute kickbacks, and side lying leg kicks are great for a glute pump, but do not provide sufficient stimulus to create functional capacity at the hip. These types of exercises are useful for building awareness and being able to feel the glute muscles working in the beginning stages of rehab, but they need to be progressed away from rather quickly to get someone back on their feet.