Posts Tagged ‘muscle function’


 

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

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Despite their name, the adductor muscles work primarily as strong sagittal plane hip flexor or extensors. For example, if you are walking (or running) and the right leg is forward, the right adductor works as an extensor and the left as a flexor and then they switch as you alternate legs in the cycle. Have you ever went out and ran or sprinted for the first time? Where did you feel sore? Right, in the groin and inner thighs (as well as the rest of your body if was your first time).
The adductors (generally) attach proximally to the pubic bone and distally attach to the posterior medial aspect of the femur, giving them their mechanical advantage in the sagittal plane. In single leg stance or the single leg phase of gait running or kicking they work with the gluteus medius and the quadratus lumborum to stabilize the pelvis and limb in the frontal plane on the stance side. Now, in activities such as gymnastics, ballet, and karate where the leg is lifted or rapidly “thrown” out to the side the adductors will actually adduct the leg to bring it back into position to hit the ground.

Due to its atachment to the pubic bone, the adductors when activated, can stimulate (turn on) the pelvic floor muscles.  So, squeezing something between the legs while doing a bridge or squat for example can increase pelvic floor activity, which is important for women who have had multiple childbirths and people with core stabilization issues.

Some examples of functional exercises that activate the adductors include:  lunges – forward, lateral and posterior lateral w/ rotation, step up w/ opp. leg hip flexion (w or w/out resistance from cuff or cable), single leg balance w/ opp. leg reaches, and resisted walk, jog or running (cable, bungie, sled).

Once you understand what the bones are doing in all 3 planes (against gravity, ground reaction forces and momentum) and you know where the muscle attaches proximally and distally, you can begin to figure out its true function and design exercises to actually improve the bodies abilitiy to move.  Unfortunately, school doesnt usually teach us that.  Think back to anatomy.  We are taught that the adductors adduct the leg.  Well, now we know that in function they rarely ever do that!  Good luck and have fun!  There is always more to learn!

Get Strong! Stay Strong!

Chris

Posterior Tibialis: Attaches proximally to post aspect of tibia and distally attaches to almost everything under the foot (cuboid, navicular, cuneiforms).  During pronation (loading phase) it eccentrically controls tibial advancement in the sagittal plane(SP), tibial internal rotation in the transverse plane(TP) and eccentrically controls lateral to medial loading of the foot in the frontal plane(FP).

Soleus: Attaches proximally to post surface of tibia and distally forms achilles tendon to attach slightly medial on the calcaneus.  During the loading phase it eccentrically controls tibial advancement in the sagittal plane, tibial internal rotation in the transverse plane and calcaneal eversion in the frontal plane.

In most anatomy classes it is taught that the function of the posterior tibialis. is to plantar flex (point) and invert the foot and the soleus plantar flexes the foot.  Unfortunately, when your foot is on the ground this does not and cannot happen as was explained above.  After an injury or surgery many people walk on a bent knee.  Assuming they have full passive extension, the problem is a posterior tibialis and soleus that are not functioning properly.  When the foot hits the ground and begins to pronate, the soleus is ecc. controlling calcaneal eversion (FP), the post. tib. and soleus are ecc. controlling tibial advancement(SP) and internal rotation(TP) and the tib. post. is controlling the lateral to medial loading of the foot.  This all occurs through late mid stance of gait (normal pronation).  Then the foot/leg begin to supinate (unload) in order to lock up the joints to push off on a rigid lever.  The soleus inverts the calcaneus while the post. tib. and soleus concentrically “pull” back on the tibia and externally rotate it.  Meanwhile momentum is carrying the rest of the body “over the top” and thats what creates knee extension during gait.  It really has nothing to do with the quad, which is taught in school to extend the knee.  School anatomy really didnt prepare me or others to treat movement dysfunction and injury in the real world.  Thank goodness I was fortunate to meet Gary Gray early in my career.  He really opened my eyes to true “functional anatomy.”  For that I am grateful.

It is truly a never ending journey.

Get Strong! Stay Strong!

Chris