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

Calf strength screen?  Um, maybe not. Specifics matter.
Thanks to barbellphysio.com for putting this up. We would like to take this deeper, because it is very important.
This screen in our strong opinion is mostly for testing sub optimal endurance, sure there is some strength assessment going on but if you are trying to determine strength, is it single rep strength ? Very likely what he truly meant is how does the calf strength hold up at a 20 rep endurance challenge.  This is more accurate and we are fussing about specifics here, but specifics matter.
*However, the potentially BIG HOLE here in the assessment, is that “perceived” top end calf/heel raise ROM is not necessarily top end FULL ROM. If one side is truly weak, and you cannot get to top end strength (say the heel is 10% lower than the other side) someone has to be there to assess and notice that top end strength failure (a top end ROM that could reduce as endurance challenge continues, but someone has to be there to observe. Going on just “feel” alone is a bad recipe there). One like is not going to feel that top end range loss even if it is large, you will perceive the effort which could feel the same as the good side but actually be a loss.  And is 20 reps enough? Sure, it is a start but is your test really telling you what you think it is telling you ? This is being shown as a gross screen in our opinion but it has holes even as a screen.  Top end strength, something we talk about here often, is critical to performance. Top end loss means  terminal plantarflexion ROM is insufficient, and this can lead to a whole host of injuries and biomechanical flaws including achilles tendonopathy to mention just one. Remember, the gastroc does  not play alone here (and gastrocs crosses the knee joint posteriorly, some of the other posterior compartment muscles do not). There is soleus, peronei, tib posterior, long flexors etc. So are you doing your test with bent knee or locked ? It makes a difference if you are trying to tease things out.  Are you ramming your toes into flexion to get more out of them to make up for a loss elsewhere ? Is the forefoot or rearfoot inverting or everting  on the up or down phase ? These things matter. Specifics matter.  For example, you can see in this video that the hip is a little lateral to the foot placement. This will mean that the heel rise will result in a lateral forefoot weight bearing load. Do you want to see if the peronei are doing their job during the heel rise ? Well then you should go into a hip hike to posture the hip over the foot so that you can get the weight bearing transition to occur terminally over to the big toe, the peronei and lateral gastroc help drive that last little shift and if they are weak and you are not driving that last piece of the movement the test may not show you the whole picture you are thinking it is. Clue, if you cannot feel the lateral compartment contract to finalize that medial foot weight bearing load shift, you may be weak there. You better assess then.

Can you do 20 reps at 80% of the full plantarflexion ROM or can you do 20 reps at 100% full plantarflexion ROM ? There is a performance difference, and to the client unobserved, the 80% on one side may feel and perform like the 100% on the other side. But make no mistake, there is a world of difference.  Someone has to  watch that you are comparing apple to apples, and not apples to figs, oranges, turnips or squash.
-Dr.Shawn Allen, the gait guys

https://www.youtube.com/watch?time_continue=55&v=QdWiXHsI8Q8

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. 

CAI: More on Chronic Ankle Instability.

More peroneii action! In folks with chronic ankle instability, it contracts earlier, longer (throughout stance phase) but not stronger…This article looks at activation times and patterns of folks with chronic ankle instability. 

One should never wonder why repeated ankle sprains occur. We have hit this topic hard in the past.  Chronic Ankle Instability (CAI) clients exhibit prioprioceptive and postural control challenges. According to this article, additionally, CAI clients have gait. 

Time of activation for all muscles tested occurred earlier in the CAI group than in the control group. The peroneus longus was activated for a longer duration across the entire stride cycle in the CAI group.”

Individuals with CAI demonstrated neuromuscular-activation strategies throughout the lower extremity that were different from those of healthy control participants. “

Did you see our trademark “goto” exercise in yesterday’s social media Facebook blog post ?  It is a keeper if you ask us.  Don’t ignore chronic peroneal challenges, they will come back to haunt you.

_________

Lower Extremity Muscle Activation in Patients With or Without Chronic Ankle Instability.  Mark A. FegerMEd, ATCLuke DonovanMEd, ATCJoseph M. HartPhD, ATCJay HertelPhD, ATC, FNATA, FACSM Department of Kinesiology, The University of Virginia, Charlottesville

http://www.natajournals.com/doi/abs/10.4085/1062-6050-50.2.06 

Results:  Time of activation for all muscles tested occurred earlier in the CAI group than in the control group. The peroneus longus was activated for a longer duration across the entire stride cycle in the CAI group (36.0% ± 10.3%) than the control group (23.3% ± 22.2%; P = .05). No differences were noted between groups for measures of electromyographic amplitude at either preinitial or postinitial contact (P > .05).

Conclusions:  We identified differences between the CAI and control groups in the timing of muscle activation relative to heel strike in multiple lower extremity muscles and in the percentage of activation time across the entire stride cycle in the peroneus longus muscle. Individuals with CAI demonstrated neuromuscular-activation strategies throughout the lower extremity that were different from those of healthy control participants. Targeted therapeutic interventions for CAI may need to be focused on restoring normal neuromuscular function during gait.

More research on the peronei and chronic ankle instability.

More peroneii action! In folks with chronic ankle instability, it contracts earlier, longer (throughout stance phase) but not stronger…This article looks at activation times and patterns of folks with chronic ankle instability. 

One should never wonder why repeated ankle sprains occur. We have hit this topic hard in the past. Chronic Ankle Instability (CAI) clients exhibit prioprioceptive and postural control challenges. According to this article, additionally, CAI clients have measurable gait changes. 

“Time of activation for all muscles tested occurred earlier in the CAI group than in the control group. The peroneus longus was activated for a longer duration across the entire stride cycle in the CAI group.”
“Individuals with CAI demonstrated neuromuscular-activation strategies throughout the lower extremity that were different from those of healthy control participants. “

Did you see our trademark “goto” exercise in yesterday’s social media Facebook blog post ? It is a keeper if you ask us. Don’t ignore chronic peroneal challenges, they will come back to haunt you.

_________

Lower Extremity Muscle Activation in Patients With or Without Chronic Ankle Instability. Mark A. Feger, MEd, ATC; Luke Donovan, MEd, ATC; Joseph M. Hart, PhD, ATC; Jay Hertel, PhD, ATC, FNATA, FACSM Department of Kinesiology, The University of Virginia, Charlottesville

http://www.natajournals.com/doi/abs/10.4085/1062-6050-50.2.06

More on the the peroneus:


It seems that too much of a good thing (ie pronation or supination) slows down the peroneus. A slower contraction time as the foot moves from midstance to terminal stance (when the peroneus longus contracts to assist in descending the 1st ray) appears to biomechanical consuquences…

“RESULTS: Participants with pronated or supinated foot structures had slower peroneus longus reaction times than participants with neutral feet (P = .01 and P = .04, respectively). We found no differences for the tibialis anterior or gluteus medius.

CONCLUSIONS: Foot structure influenced peroneus longus reaction time. Further research is required to establish the consequences of slower peroneal reaction times in pronated and supinated foot structures. Researchers investigating lower limb muscle reaction time should control for foot structure because it may influence results.”

J Athl Train. 2013 May-Jun;48(3):326-30. doi: 10.4085/1062-6050-48.2.15. Epub 2013 Feb 20.
Foot structure and muscle reaction time to a simulated ankle sprain.
Denyer JR1, Hewitt NL, Mitchell AC.

#gait
#thegaitguys

People tend to forget about the peroneal muscles. This is what it looks like when the brain forgets.

This client came to see us for obvious reasons but the case details are not what we are focusing on today. Gait gets pretty messed up when a critical component or phase is lost or forgotten.  

In last weeks teleseminar on www.onlineCE.com we discussed several gait cases. In these cases 5 things kept coming up when it came to looking at (specifically) neurologic gait compensations:

  1. slowing of gait
  2. wider based gait
  3. increased ancillary movements 
  4. utilizing support when needed or available
  5. shorted step length and stride length

In this video, it is clear that this person has some serious neurologic problems engaging the peroneal muscles and controlling ankle and foot function and as a consequence you see evidence of some of the itemized issues above, namely, calculated movements, nearly zero arm swing and step length from left to right is abbreviated. 

It can go both ways. The neurologic problem can affect one’s gait, but one’s resultant gait can then affect cortical function, driving an endless loop. Recently, five studies presented at the Alzheimer’s Association International Conference in Vancouver Canada provided striking evidence that when a person’s walk gets slower or becomes more variable or less controlled, his cognitive function is also suffering.(2)  

A person’s gait and their neurologic function cannot be separated. The stuff just run’s too deep.  This is why we love gait so much, because to fully understanding someone’s clinical problems we must understand how and why they move.  There are clues in everyone’s gait that can help you clinically. The question is, will you notice them ? Do you know what normal gait is to begin with ? Will you understand what you are seeing and realize it is a compensation? Will you fix what you see or look deeper to find the cause of what you see ? 

Shawn and Ivo,

The Gait Guys

Gait Posture. 2013 Jul;38(3):549-51. doi: 10.1016/j.gaitpost.2013.02.008. Epub 2013 Mar 11.

Altered gait termination strategies following a concussion.

Buckley TA1, Munkasy BATapia-Lovler TGWikstrom EA.

2.  http://www.nytimes.com/2012/07/17/health/research/signs-of-cognitive-decline-and-alzheimers-are-seen-in-gait.html?_r=1&