How well do you understand stance phase mechanics?

Here is a recent question we fielded and thought it would make a great post. 

Question/Comment: I’m slightly confused about closed chain hip motion in the stance leg.

Maybe if I explain what my thought process is you can correct me.  Lets use
left stance phase with the right leg swinging through.

After right mid-swing, the pelvis will be rotating towards the left.  The
motion of the pelvis on the left femur would be relative femur internal
rotation.  I understand that the right leg is externally rotating
(supinating) and that normal open chain kinematics of hip extension is
coupled with external rotation.  But if the pelvis is moving towards the
left AND the left femur externally rotates, wouldn’t that create too much
rotation?  So what I’m saying is that a pelvis that is oriented to the left
with a left femur that externally rotates creates an odd motion in my head
(which may be where the problem lies).  If you’ve ever seen a western where
the gun slingers do that weird walk to a shoot out…that’s what an
externally rotating femur during terminal stance looks like to me.

I’ve discussed this with other clinicians.  Some are in agreement with me,
some think it’s externally rotating, and some don’t know what I’m talking
about.  In my patients I also see a loss of hip IR more than hip ER.  These
patients that lose hip IR seem to have more difficulty in terminal
stance/toe-off phase more than the ones that lose hip ER.

If you could help me understand these kinematics and clear this up for me I
would greatly appreciate it.

Thank you, A

our reply: 

Taking your example with the L leg in stance:
When the L heel contacts the ground, the friction of the ground (hopefully) slow the calcaneus and the talus slide anteriorly on the calcaneus. 

Because of the shape of the calcaneal facets, the talus plantar flexes, adducts and everts. This sets the stage for pronation to occur: the calcaneus everts and the lower leg internally rotates, with the thigh following. The right side of the pelvis is moving to the L (counter clockwise rotation). This should occur (ideally) until midstance. At midstance, the opposite ® foot begins to enter swing phase; this should initiate supination of the stance phase leg (L). At this point, the L foot should be beginning to supinate the the leg and thigh beginning external rotation. It (thigh and leg) should reach maximal external rotation at toe off (maximal counter clockwise rotation of the pelvis) and remain in external rotation until heel strike/initial contact on the L side again. At this point, the pelvis begins clockwise rotation.

It is necessary for the thigh and leg to externally rotate while the pelvis is rotating counter clockwise, because of the constraints of the iliofemoral, pubeofemoral and ishiofemoal ligaments.

We too often see a loss of internal rotation of the hip in symptomatic populations more often than external rotation.

We hope this clarifies things for you.

Thank you again for the question and taking the time to write.

The Gait Guys

Does this guy have a short leg or what? How good are your eyes?

One again, we had the gait cam, investigating gait on the east coast. What do we see in this gent?

  • heel strike on out side of left foot with increased progression angle

he appears to be stabilizing the left side during stance phase. notice the upper torso shift to the left during left stance phase

  • abbreviated arm swing on right

note that ankle rocker is adequate on the left

  • body lean to right on right stance phase

gluteus medius weakness on right? short leg on right?


  • Did you also notice the loss of ankle rocker on the right, compared to the left? This results in less hip extension on that side as well.
  • He flexes his right thigh less than his right during pre swing and swing

external obliques should be firing to initiate hip flexion, perpetuated by the psoas, iliacus and rectus femoris. This does not appear to be happening.

All of this is great BUT nothing like being able to actually examine your patients is there? You can see how gait analysis can tell us many things, but they need to be confirmed by a physical exam.

The Gait Guys. Educating (and hopefully enlightening) with each post. Keep your eyes open and your thinking from the ground up : )

Got Arm Swing?

We have written many times about arm swing. Click here for some of our posts here on Tumblr.

Here we are again at the beach. Look at the beautiful difference in arm swing from side to side in the guy carrying the bag. Makes you want to tell him to use a backpack, eh?

Never mind what it does to his gait

  • decreased arm swing on the carrying side
  • increased step length on the left side
  • increased thigh flexion of the left side
  • increased body lean and head tilt to right side (Take a look at this paper)

think about the increased metabolic cost. Think about what this  type of input (increased amplitude of movement unilaterally) is doing to your cortex!

keep your movements symmetrical, folks!

The Gait Guys

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.

This is part 2 of a 2 part post; with the video from the case previously discussed

please note the following in the video:

  • body lean to left during left stance phase (to clear right longer leg)
  • circumduction of right lower extremity  (to clear right longer leg)
  • lack of arm swing bilaterally (cortical involvement)
  • patient looking down while walking (decomposition of gait)
  • shortened step length (decomposition of gait)
  • increased tibial varum bilaterally

ASSESSMENT:  This patient’s short leg and internal tibial torsion impediments to her full recovery. She has increased tibial varum noted which is complicating the picture. This is causing pathomechanics and an abductory moment not only at the knee but also in the lumbar, thoracic and cervical spines.

WHAT DID WE DO?:                    

  • We attempted to do the one leg standing exercise. She needed to hold on and did not feel stable on the left hip while performing this.  This is probably more of confidence rather than ability issue. 
  • We gave her the stand/sit exercise to try to improve gluteal recruitment.
  • We also gave her the lift/spread/reach exercise to attempt to strengthen her feet.
  • A full-length 5 mm lift was cut for the left shoe  She felt more stable when walking on this.
  • She was treated with IC, PIR and manipulative therapy and neuromuscular stim of the knee as well as left hip area above, below and at the joint line of the knee as well as gluteus medius and minimus.   
  • We may need to consider building a more aggressive orthotic with a forefoot varus post depending upon her progress and response to care  

 The Gait Guys. Making it real, each and every post here on the blog.

special thanks to SZ for allowing us to publish her case, so others can learn

Wow! What would you do?

This is part 1 of a 2 part post. Look for the other one a few minutes after this one with a video up top for the conclusion

PRESENTING PROBLEM: This 54 YO female patient presents with with left sided knee pain.  She had a total knee replacement (TKR) done in 2011.  She’s had a significant amount of discomfort on the medial aspect of the knee since then. She had an MRI of the hip done thinking the problem was there, and found nothing.   She is walking with a bad limp, left leg is half inch shorter than the right.  Pain is worse at night, changes with weather. 

She has knee pain on the lateral aspect (points to tibial plateau and joint line) with swelling that goes down to the ankle left side.  She has been wearing a “Good Feet” OTC orthotic on the left side which she states helps quite a bit.

Generally speaking, stretching and analgesics make the discomfort better.    Ibuprofen 400 mg. b.i.d. can take the edge off  Soft sided brace (neoprene sleeve) makes a difference as well. The hard sided brace gives her difficulty.

WORK HISTORY: She works for a preschool.  Her job involves standing and getting up and down a lot.  

FAMILY HISTORY:  She has left sided lid ptosis, this evidently is familial.  

PHYSICAL EXAM:  She stood 5’ 1” and weighed approx. 150 pounds.

Viewing the knees bi-lat., the left knee is markedly externally rotated.

She does have a left short leg; tibial and femoral.  She has bilateral tibial torsion (look at the tibial tuberosities and drop a line straight down; it should pass through the 2nd metatarsal head) and marked internal tibial torsion on the left side (>60 degrees) with femoral retrotorsion (less than 8 degree angle of femoral head with the shaft) on this side.  There is no rotation of the thigh or leg past zero degrees midline. .  She had 10 degrees of tibial varum on the left hand side.  Her Q-angle is 10 degrees on that side.  There is plantar flexion inversion of the foot.  Left lower extremity has less sensation secondary to the her TKR  surgery.

Gait evaluation reveals a fair amount of midfoot pronation noted on the left hand side in addition to an intoed gait.  She has to lean her body over to the left to get the right leg to clear.

Some mild weakness noted of hip abduction musculature left hand side gluteus medius, middle and anterior fibers. Knee stability tests were negative.

Neurologically, otherwise, she had full integrity with respect to sensation, motor strength and deep tendon reflexes in the upper and lower extremities.

Please see part 2 of this post for additional info including our assessment and what WE did.

 The Gait Guys. Making it real, each and every post here on the blog.

special thanks to SZ for allowing us to publish her case, so others can learn

Podcast 69: Advanced Arm Swing Concepts, Compensation Patterns and more

Plus: Foot Arch Pathomechanics, Knee Pivot Shift and Sesamoiditis and more !

A. Link to our server:

Direct Download:


B. iTunes link:

C. Gait Guys online /download store (National Shoe Fit Certification and more !) :

D. other web based Gait Guys lectures:   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”


Today’s Show notes:

1. “Compensation depends on the interplay of multiple factors: The availability of a compensatory response, the cost of compensation, and the stability of the system being perturbed.”
What happens when we change the length of one leg? How do we compensate? Here is a look at the short term consequences of a newly acquired leg length difference.
2. Medial Longitudinal Arch Mechanics Before and After a 45 Minute Run

3. Several months ago we talked about the pivot-shift phenomenon. It is frequently missed clinically because it can be a tricky hands on assessment of the knee joint. In this article “ACL-deficient patients adopted the … .* Remember: what you see in their gait is not their problem, it is their strategy around their problem.

4.Do you know the difference between a forefoot supinatus and a forefoot varus?
“A forefoot varus differs from forefoot supinatus in that a forefoot varus is a congenital osseous deformity that induces subtalar joint pronation, whereas forefoot supinatus is acquired and develops because of subtalar joint pronation. “

5. Pubmed abstract link:
Gait Posture. 2014 Jun;40(2):321-6. Epub 2014 May 6.
Arm swing in human walking: What is their drive?
Goudriaan M, Jonkers I, van Dieen JH, Bruijn SM

6. This is Your Brain On Guitar