More on landing mechanics.
Here is a recent article on landing mechanics. This article talks about the landing mechanics far past where I feel the first stage of vulnerability is, which is initial forefoot load, as i discuss in the video pertaining to landing from a jump or if sprinting (forefoot loading). IF landing occurs in low gear (lateral half of the forefoot), inversion risks are higher.
The medial foot tripod, high gear toe off (1st and 2nd mets) is where we should be taking off from, and landing initially upon. Anything lateral is vulnerable without the lateral column strength (lateral gastrocsoleus complex, peronei longus/brevis).
This article talks about knee flexion angles and ACL vulnerability, far after this initial loading response. The article some valid conclusions in that phase.

– Dr. Shawn Allen

Posture specific strength and landing mechanics.

http://lermagazine.com/article/posture-specific-strength-and-landing-mechanics

https://www.youtube.com/watch?v=8T9UzOaYxmo

Ankle sprains and the reorganization of the sensorimotor system

“Our subjects with unilateral chronic ankle sprains had weaker hip abduction strength and less plantar-flexion range of motion on the involved sides. Clinicians should consider exercises to increase hip abduction strength when developing rehabilitation programs for patients with ankle sprains.”-Friel et al

Awhile back we wrote about the principle that if the hip abductors are weak, the leg will posture more adducted (ie, cross over type pattern) and this places the foot more directly below the body midline plumb, this will posture the foot in inversion and thus at greater risk for future inversion sprains.  This sets up the vicious cycle of hip abductor weakness, frontal plane drift of pelvis, inversion of the foot and more ankle sprain risks/events.  The cycle must be broken. The hip must be addressed. That lateral chain must be restored all the way up from the foot.  

Another newer study by Bowker discusses the somatosensory feedback necessary for postural adjustments, walking, and running stating that they may be hampered by a decrease in soleus spinal reflex excitability.  The study adds more validity to what we are all growing to know more clearly, that the central nervous system via supraspinal circuitry plays deeply into chronic ankle instability (CAI). The studies suggest that CAI may be more about coordination and control of dynamic stabilizers and changes in the motor neuron excitability rather than the function of static stabilizers.

“A successful reorganization of the sensorimotor system after an initial ankle sprain is the critical point when individuals suffer chronic ankle instability or become copers [individuals who do not develop chronic instability after an ankle sprain] who break the cycle of recurrent injuries and disabilities seen in CAI,” Masafumi Terada, PhD

According to LER and the Terada work, 

The slow-twitch fibers in the soleus muscle are mostly innervated by small alpha motoneurons, Terada explained, so the study findings suggest that some people may restore their ability to reflexively recruit alpha motoneurons after ankle injury, and some may not.

“Therapeutic interventions that can increase the H-reflex in the soleus may help to break the cycle of recurrent injuries and disabilities seen in CAI,” he said. “Lower-intensity transcutaneous electrical stimulation, joint manipulations, and reflex conditioning protocols may be effective in increasing the soleus spinal excitability.”

The Gait Guys

Reference:

CAI and the CNS: Excitability may influence instability. Larry Hand

http://lermagazine.com/news/in-the-moment-sports-medicine/cai-and-the-cns-excitability-may-influence-instability

Taken from original source:

Bowker S, Terada, M, Thomas AC, et al. Neural excitability and joint laxity in chronic ankle instability, coper, and control groups. J Athl Train 2016 Apr 11. [Epub ahead of print]

J Athl Train. 2006; 41(1): 74–78.PMCID: PMC1421486Ipsilateral Hip Abductor Weakness After Inversion Ankle SprainKaren Friel,Nancy McLean,Christine Myers, and Maria Caceres
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1421486/

The diaphragm and chronic ankle instability.

I have been treating the global manifestations of unaddressed chronic ankle sprains for decades now. I am never unsurprised to find frontal plane hip weakness and dysfunction of the same side obliques , shoulder and spinal stabilizers. Here is one more piece of proof that unaddressed ankles are monster problems, slowly eroding the stability of the system.
But, shame on those who attempt to simplify this, just correcting the breathing and throwing some corrective spinal stability work at this problem. This approach will fail, repeatedly. At some point the ankle has to be addressed and the impaired supra spinal programming. Gait will have to be retrained as well, forget to do this and your efforts will be muted.
-Dr. Allen

“Previous investigations have identified impaired trunk and postural stability in individuals with chronic ankle instability (CAI). The diaphragm muscle contributes to trunk and postural stability by modulating the intra-abdominal pressure. A potential mechanism that could help to explain trunk and postural stability deficits may be related to altered diaphragm function due to supraspinal sensorimotor changes with CAI.”

Reference:

Diaphragm Contractility in Individuals with Chronic Ankle Instability.

Terada, Masafumi; Kosik, Kyle B.; McCann, Ryan S.; Gribble, Phillip A.  Medicine & Science in Sports & Exercise:

http://journals.lww.com/acsm-msse/Abstract/publishahead/Diaphragm_Contractility_in_Individuals_with.97497.aspx

Ankle spains and hip abductors

We see it ALL THE TIME. But sometimes it is nice to point out the obvious, just in case you are not looking for it.
“Conclusions: Our subjects with unilateral chronic ankle sprains had weaker hip abduction strength and less plantar-flexion range of motion on the involved sides. Clinicians should consider exercises to increase hip abduction strength when developing rehabilitation programs for patients with ankle sprains.”-Friel et al
Dr. Allen: if the hip abductors are weak, the leg will posture more adducted (ie, cross over type pattern) and this places the foot more directly below the body midline plumb, this will posture the foot in inversion and thus at greater risk for future inversion sprains.  This sets up the vicious cycle of hip abductor weakness, frontal plane drift of pelvis, inversion of the foot and more ankle sprain risks/events.  The cycle must be broken. The hip must be addressed. That lateral chain must be restored all the way up from the foot.  All stuff you likely already know, but good to find another study to validate.

Dr. Allen

J Athl Train. 2006; 41(1): 74–78.PMCID: PMC1421486Ipsilateral Hip Abductor Weakness After Inversion Ankle SprainKaren Friel,Nancy McLean,Christine Myers, and Maria Caceres
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1421486/

Podcast 91: Gait, Vision & some truths about leg length discrepancies

Show sponsors:
www.newbalancechicago.com

A. Link to our server:
http://traffic.libsyn.com/thegaitguys/pod_91f.mp3

Direct Download:
http://thegaitguys.libsyn.com/91

Other Gait Guys stuff

B. iTunes link:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

C. Gait Guys online /download store (National Shoe Fit Certification and more !) :
http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:
Monthly lectures at : www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

Our Book: Pedographs and Gait Analysis and Clinical Case Studies

electronic copies available here:

Amazon/Kindle:

http://www.amazon.com/Pedographs-Gait-Analysis-Clinical-Studies-ebook/dp/B00AC18M3E

Barnes and Noble / Nook Reader:

http://www.barnesandnoble.com/w/pedographs-and-gait-analysis-ivo-waerlop-and-shawn-allen/1112754833?ean=9781466953895

https://itunes.apple.com/us/book/pedographs-and-gait-analysis/id554516085?mt=11

Hardcopy available from our publisher:

http://bookstore.trafford.com/Products/SKU-000155825/Pedographs-and-Gait-Analysis.aspx

Show notes:

Gait and vision: Gaze Fixation
What’s Up With That: Birds Bob Their Heads When They Walk
http://www.wired.com/2015/01/whats-birds-bob-heads-walk/
 
Shod vs unshod
 
Short leg talk:
11 strategies to negotiate around a leg length discrepancy

From a Reader:

Dear Gait Guys, Dr. Shawn and Dr. Ivo,  I was referred to this post of yours on hip IR…http://thegaitguys.tumblr.com/post/14262793786/gait-problem-the-solitary-externally-rotated   I am impressed by the level of details of your understanding of the gait and biomechanics. Although I am still trying to understand all of your points in this post, I would like to ask you:  What if my IR is limited due to a structural issue? The acetabular retroversion of the right hip in my case. 

I.e. if I am structurally unable to rotate the hip internally.
What will happen? 
What would be a solution to the problem in that case? 

Single-leg drop landing movement strategies 6 months following first-time acute lateral ankle sprain injury – Doherty – 2014 – Scandinavian Journal of Medicine & Science in Sports
http://onlinelibrary.wiley.com/doi/10.1111/sms.12390/abstract

Hey Gait Guys,

I understand that 1st MP Joint dorsiflexion, ankle rocker, and hip extension are 3 key factors for moving in the sagittal plane from your blog and podcasts so far. I really love how you guys drill in our heads to increase anterior strength to increase posterior length to further ankle rocker. I’ve seen the shuffle gait and was curious if you had a good hip extension exercise to really activate the posterior hip extensors and increase anterior length. 

Podcast 52: Limb Dominance & Other Cool Stuff

A. Link to our server:

http://thegaitguys.libsyn.com/podcast-52-limb-dominance-other-cool-stuff

B. iTunes link:

https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

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

http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

________________________________________

* Today’s show notes:

Neuroscience:

1. The Potential Downside of Wearable Biomechanical Monitoring Devices for Running

http://runblogger.com/2014/01/downside-of-wearable-biomechanical-monitoring-devices-for-running.html

2. Google’s Next Crazy Project: Smart Contact Lenses | Entrepreneur.com
http://www.entrepreneur.com/article/230927

3. How Humans Burn Fewer Calories Than Other Mammals

http://www.runnersworld.com/weight-loss/how-humans-burn-fewer-calories-than-other-mammals

4. Update: I was listening to your podcast and you said Ice Bug was out of business. I sell them in my store in Fairbanks Alaska where we have snow and ice on the ground for 6-7 months a year. The US distributor is Ice Bug USA. I also carry a the Salomon Snow Cross studded shoe.
The effects of limb dominance and fatigue on running biomechanics
http://www.gaitposture.com/article/S0966-6362(13)00702-9/abstract
5. Email case:
Dear Gaitguys,
   I have been on a search since October to determine the cause of my chronic tendonitis in my knees and right hip. Through my search I was told that my femurs are rotated internally and my tibia are externally rotated. This is causing my patella to face inward.
  I was told by one PT that I will never be able to run long distances without developing tendonitis. I want to believe he is wrong because I love running. I came across something called Femoral Anterior Glide in my research and was wondering if you guys believe this is a real condition. Also is there a way a person can know if they have this problem?
Thank you for all of your great posts!
 Kate 
6. Blog reader:

My 11 year old son walks with a very noticeable external tibial torsion. We just recently noticed this and I came upon your site while trying to research it. I also read that many time it has to do with a problem with the patella. Both my husband and daughter have had patella problems but do not have the duck walk like my son. I did ask a a pediatric sports medicine specialist about the problem and he said some kids just walk that way. Where should I bring my son for help with this?

7. Blog reader asks:

About a year ago there was an article posted called: “A case of the non-resolving ankle sprain. Things to think about when the ankle and foot just do not fully come around after a sprain”. I am 15 weeks into an identical problem and I was wondering if there was any way you guys could follow up with “MR” to see if he was ever able to resolve his issue. It is such a unique and frustrating case (being able to walk but not run) and I haven’t found any other instance of it until now. Thank you.

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

http://store.payloadz.com/results/results.aspx?m=80204

9. Second metatarsal osteotomies for metatarsalgia: A robotic cadaveric study of the effect of osteotomy plane and metatarsal shortening on plantar pressure – Trask – 2013 – Journal of Orthopaedic Research – Wiley Online Library

http://onlinelibrary.wiley.com/doi/10.1002/jor.22524/abstract;jsessionid=BCFFA5207512C41214E7F3D601729EFE.f01t01

Podcast 45: Spock, Ankle Syndesmosis injuries and Subways.

4.Scanadu scores $10.5M and paves the way for FDA trials

5 . National Shoe Fit Program
Knee Surg Sports Traumatol Arthrosc. 2010 Oct;18(10):1379-84. doi: 10.1007/s00167-009-1010-y. Epub 2009 Dec 18.

Rotational laxity greater in patients with contralateral anterior cruciate ligament injury than healthy volunteers. Branch TP, 

 7.from a blog reader:
schwad01 asked you:
Guys. I am a Parkinson’s patient … 
 
8. FAcebook reader:
9. In the News:

Russian Subways Now Accept Squats for Payment

10.In the research:
11.GAME: