Get Your Booty to "Bark"! Muscle Function

OK, since I enjoy talking about function and biomechanics lets talk about how to turn on your butt!  Thought that might get someones attention.  Any way, the Gluteal/hip/ butt muscles are the "powerhouse" muscles.  We call them the big house or the cannon.  The first thing to do before "shooting" the cannon is to "load" the cannon.  In function this simply means you need to efficiently load (eccentrically)the gluteus muscles in order to effectively unload or more forcefully create a concentric contraction.  During the loading or pronation phase ( front foot hits the ground in lunge or gait)

   the function of the gluteus muscles (max, min and med) is to eccentrically control hip flexion in the sagittal plane, hip adduction in the frontal plane and femoral/hip internal rotation.  If you look at an anatomy picture of the gluteus maximus you will notice that the fiber orientation is primarily in the transverse plane.  This baby was designed for femoral/hip rotation (a significant component of lower extremity pronation)

The gluteus attaches proximally to the saccrum and the illiac crest and distally to the greater trochanter and blends with the tensor fascia latae (TFL) to form the illiotibial band.  The ITB attaches distally to the anterior/lateral aspect of the tibia.

So, for example, when you are walking and your foot hits the ground and begins to pronate, the calcaneus everts causing the tibia to advance forward and internally rotate (see "When Foot Hits Ground" post).  This creates a quick "pull" on the ITB, which creates a quick stretch on the gluteus thereby stimulating the butt to contract.  This is further accentuated by the femoral internal rotation that also eccentrically lengthens the gluteus maximus.  Remember that neurologically a muscle responds to a quick stretch (eccentric load) by concentrically contracting. Therefore, if one has limited calcaneal eversion (after ankle injury or immobilization) they will not be able to effectively and efficiently turn on the butt which leads to compensation and further problems.  There in lies the beauty of function!

Get Strong! Stay Strong!

Chris

Do You Have Dormant Butt Syndrome??

Yes, I said dormant butt syndrome, DBS for short! I see it all the time in the clinic. In athletes and people of all ages. The cause of DBS is usually tight hip flexors, again, which most people have. This is due to repetitive hip flexion from walking, running, sitting, driving and sleeping in the fetal position. Other causes include injury and inactivity. If you remember back to previous posts the gluteus maximus generally attaches proximally to the sacruum, and illiac crest and wraps around the hip to distally attach to the greater trochanter (the big bony bump on side of hip). Although we think of the gluteus maximus as a powerful hip extender it is actually built for rotation. Just look at the fiber orientation (yes, you may have to crack open the old anatomy book). So, functionally its main function is to eccentrically control internal rotation of the femur in the transverse plane during the loading phase of gait or running, eccentrically control hip flexion in the sagittal plane and assist the gluteus medius in stabilizing hip adduction in the frontal plane. The ability to appropriately load enhances their ability to concentrically contract during the unloadong or propulsive phase. If the gluteus maximus is inhibited (which V. Yanda taught us) from a tight hip flexor, then the hamstrings and erector spinae group become overactive to compensate. This leads to the possibility of hamstring strains, low back pain, knee pain and possibly even plantar fascia. A simple way to check for DBS is to have patient lie prone and ask them to do a leg lift. Palpate the gluteus and the hamstring and see which contracts first. Many times I feel the hamstring contract then the gluteus. It should be gluteus then hamstring. Sometimes ive seen people have a 5/5 manual muscle test and not even fire the gluteus. They used all their hamstring and erectors to lift/hold the leg up. Some general strategies include a basic muscle re-education of laying prone over table or bed and actively squeezing butt then lifting leg. Sequence can also be done with bridge exercise. Stretching the tight hip flexor, of course, and functional hip dominant exercise like single leg balance w/ arm reaches, multi planar lunges, sled walks, various step up and downs. So now get moving and wake that sleepy butt up!

Get Strong! Stay Strong!

Chris