Psoas, iliacus. . . .  hip flexors ?

How many times have you heard us say, “hip flexion in the swing phase of gait is not driven by the hip flexors. In swing phase, the psoas and iliacus complex is not a hip flexor initiator, it is a hip flexion perpetuator/” ?
More evidence … . .
“These experiments also showed that the trailing leg is brought forward during the swing phase without activity in the flexor muscles about the hip joint. This was verified by the absence of EMG activity in the iliacus muscle measured by intramuscular wire electrodes. Instead the strong ligaments restricting hip joint extension are stretched during the first half of the swing phase thereby storing elastic energy, which is released during the last half of the stance phase and accelerating the leg into the swing phase. This is considered an important energy conserving feature of human walking. ”

A profound loss of hip extension…

While sitting on the beach, our mind never rests. Even when on vacation we continue to watch how people move.

Luckily today, I had the gait cam (Dr Allen is holding down the Gait Guys Fort), so live from Sunset Beach, it’s Sunday night. See of you can see what I saw.

Sitting with my wife and watching the kids dig in the sand, this gal with the flexed posture caught my eye.

Why is she so flexed forward? The profound loss of hip extension made it impossible for her to stand up straight! It was difficult to say if she has bilateral hip osteoarthritis, or possible bilateral THR’s (total hip replacements), maybe just really tight hip flexors, painful bunions that do not like toe off, or even all of the above. She may have a leg length discrepancy, as she leans to the left on left stance phase; of course she could have weak hip abductors on the left. It does not appear she has good control of her core.

What do we see?

  • flexion at the waist
  • loss of hip extension
  • body lean to left at left midstance
  • shortened step length
  • loss of ankle rocker
  • premature heel rise
  • decreased arm swing (she is carrying something in her left hand)

No one is safe from the gait cam! Stay tuned for more beach footage this week!

We remain, The Gait Guys, even on vacation.

Muscle Activation Concerns

We are concerned about some things that are showing up in our clinics lately. Strange injury patterns we have not seen before. We know you are all very busy, because you are the best what you do, but we hope that by sharing these 2 articles with you we can all further raise this team of practitioners, coaches, physical therapists, trainers, pilates and yoga instructors, surgeons etc and work even more effectively as a team.  
This issue is about muscle activation or facilitation.
As you are all learning, this game is more than just turning muscles on, and there are risks to turning something on when the central nervous system has decided it is not safe to turn something on. We are all treating people who are slouched over all day either as students or at desk jobs and thus everyone (seeing as they are all dropped into hip, knee and cervical, thoracic and lumbar spine flexion) will have some degree of inhibited glutes (and thus reciprocal neuro-protective hip flexor tightness) that appear to need activated when the truth is that they need more central extension facillitation. Activating the glutes when there is a central flexion inhibition driver overrides the nervous system’s protective inhibition response. Hence the near-epidemic of hamstring and hip flexor/groin/labrum tear problems we are seeing !   There are logical reasons why something is not activated. Sometimes it is a 
1. muscle skill pattern (large diameter nerve, all muscle fiber diameters), 
2. sometimes it is an endurance problem (large diameter nerve, small muscle fiber diameter),
3.  sometimes it is a strength problem (largest diameter nerve, largest diameter muscle fibers). 
Knowing a problem is driven by 2 or 3 will tell the practitioner that activation will not solve the problem and that activation can force a compensation pattern that can lead to a future injury. Also, sometimes it has nothing to do with the muscles motor nerve activity, it may in fact be about the reciprocal inhibitory neurosensory input (see our post on reciprocal inhibition here). 
Hence we wanted to share 2 articles we wrote. These articles were spurred by the magnified influx in the last year of injuries that appear compensatory, meaning they seem to have occurred because alternative compensatory motor patterns were encouraged where there appear to be clear signs that they should not have been encouraged.  In other words, sorry to say this, people with a weaker understanding of how and why the nervous system works are using muscular activation as a tool when it is the wrong tool. When you are pounding a nail, using a screwdriver won’t get you good results, and might get you the wrong results. But, if all you have is a screwdriver … . .
The blog posts are below. We strongly believe that many of these injuries we are seeing are not necessary. We always ask ourselves when a person who we have been working on says to us “honest doc, I really did not do anything, I was just running comfortably and the hamstring grabbed at me for no apparent reason.”  These stories always make us look in wards and ask “is this injury my fault ?” “Did this occur because I was activating the wrong muscles and wrong patterns thus forcing them into a less worth protective pattern because I thought I knew better than their nervous system did ?” When we want to learn we judge ourselves and our actions  harshly, for we know we make mistakes and we know we are still students. We know that if it appears simple, it might be a good time to step back and think it through a little more. 
Don’t just be an muscle “activator”, be a thinker who occasionally activates when it is appropriate.  The nervous system knows better than you do, accept this and try to figure out why it is shutting things down.
Shawn and Ivo

image from :

A brief gait analysis of a pretty famous barefooter from a pretty famous study…

OK so we know this rather famous person is on a treadmill, so yes, there is a component of preload to the hip extensors, as well as an increased deceleration component (but those are topics for another post!), but there is some great stuff to look at here.

1st off, note the great technique: mid to forefoot strike, good toe dorsiflexion (although it could stand to be a bit increased to help prepare for even better tripod contact), and good ankle rocker. You can see his excellent shock absorption, through midfoot pronation, ankle dorsiflexion, knee flexion and hip flexion. Also check out the awesome action of his peroneals on his L leg, driving that 1st ray down to the ground for a great foot tripod and prelude to supinaion

But did you notice something else? How about the lack of hip extension? He barely gets past zero. How about the flexion at the waist? We bet his hip flexors are tight! Is some of this caused by the treadmill? Probably, but we would need to see some non-treadmill footage to be sure.

The Gait Guys….No gait is safe from us