There are three major gluteal muscles, the largest and most commonly thought of being the gluteus maximus, we are going to explore it's smaller counterpart gluteus medius. Shaped like a pizza, this muscle attaches from the crest of the hip to the greater trochanter (a bony landmark of the femur/thigh bone) and is often referred to as the flamingo muscle. It plays a very critical role in posture via pelvic stabilization, during the stance phase of walking (when bodyweight rests solely on one leg), but also functions to abduct the hip (bring the leg away from your midline).
Trigger points in this muscle refer pain to the buttocks, sacrum, and along the beltline making it prime suspect in low back pain. Due to it's location on the hip it also contributes to Illiotibial Band (ITB) Syndrome and knee pain. Most people with severe glute medius tension find it hard to sleep on the affected side and have pain with walking and climbing stairs. Usually this muscle is found in a shortened/contracted state as most activities we engage in utilize the quadriceps (i.e. sitting, running, etc.). If it is tight how can it be weak? Overstretched. Because we are forward activity dominant our gluteal muscles which are pertinent in posture are not getting the strengthening that they need to do their job. Think of a rubber band, if you stretch it out it is taut but over stretched at the same time. This same phenomenon is happening within our bodies. The quadriceps, and other hip flexors that attach to the front of the pelvis, pull the pelvis forward causing all other muscles that attach to the pelvis to stretch. Other factors that contribute to glute medius shortening are: iliosacral misalignment, nerve injury (glute medius' nerve stems from L5 which is the most commonly injured), and tendon rupture. A recent study has found 70% of people with back/leg pain also have a weak glute medius. In fact more research is being conducted into the correlation between glute medius tendon tear and low back pain.
So is your low back pain being caused by glute medius? Could be, a good way to test for weakness is to stand on one leg. If your pelvis tilts toward one side you have a weak glute medius muscle. Before you run off to do some squats keep in mind that this muscle is not firing properly and may need to be released of trigger points first before loading more stress, this can be achieved via massage therapy.
Once you are cleared and ready to strengthen this muscle remember that it is nicknamed the "flamingo muscle" for a reason. Squats will be engaging more of the gluteus maximus muscle. The best way to whip this muscle into shape will be with single leg deadlifts. Be sure to start without weights to ensure proper technique. To begin: stand on one leg, hinge at the hips until your torso is parallel to the ground, have a slight bend in the knee, and keep your head looking ahead of you. Once you are ready to add weight simply hold your kettlebell in the opposite hand of the leg that is rooted to the ground (i.e. standing on left leg then your kettlebell will be in your right hand). This is an excellent warm up/cool down for any program.
Have fun getting fit to move pain free!