Yay for the lift, spread and reach exercise!

Toe spreads and squeezes are aimed at strengthening specific intrinsic foot muscles—the dorsal and plantar interrosei, according to Irene S. Davis, PhD, PT, director of the Spaulding National Running Center and a professor in the Department of Physical Medicine and Rehabilitation at Harvard Medical School in Boston. Doming or foot shortening exercises contract most of the muscles on the plantar side of the foot, and help to strengthen the abductor hallucis muscle

see our post here: https://tmblr.co/ZrRYjx1iuSYMM

Goo YM, Heo HJ, An DH. EMG activity of the abductor hallucis muscle during foot arch exercises using different weight bearing postures. J Phys Ther Sci 2014;26(10):1635-1636.

A visual example of the consequences of a leg length discrepancy.

This patient has an anatomical (femoral) discrepancy between three and 5 mm. She has occasional lower back discomfort and also describes being very “aware” of her second and third metatarsals on the left foot during running.

You can clearly see the difference in where patterns on her flip-flops. Note how much more in varus wear on the left side compared to the right. This is most likely in compensation for an increased supination moment on that side. She is constantly trying to lengthen her left side by anteriorly rotated pelvis on that side and supinating her foot  and trying to “short” the right side by rotating the pelvis posteriorly and pronating the foot.

With the pelvic rotation present described above (which is what we found in the exam) you can see how she has intermittent low back pain. Combine this with the fact that she runs a daycare and is extremely right-handed and you can see part of the problem.

Leg length discrepancies become clinically important when they resulting in a compensation pattern that no longer works for the patient. Be on the lookout for differences and wear patterns from side to side.

Loss of medial tripod→

It is Rewind Friday.
Today, we are reaching back to a brief 2009 lecture I did for the local NSCA chapter on the patterns of kinetic chain compensation that match with loss of medial and lateral foot tripod. (video starts at 49 seconds, for some reason)
https://www.youtube.com/watch?v=yeCBGZkNaeM

Leg length discrepancies and total joint replacments.

5mm cut off ?  MaybeYou are likely to come across hip and knee arthroplasty clients (total joint replacements). When they take a joint out and replace it with a new one, it can be a true challenge to restore leg lengths to equality side to side. Problems often arise down the road once gait is resumed and rehabilitation is completed. It can take time for the leg length discrepancy (LLD) to begin to create compensatory problems. This article seems to suggest that 5mm is the tipping point where gait changes becoming a problem are founded. Other sources will render different numbers, this article found 5mm. The authors found that both over- and underrestoration of leg length/offset showed similar effects on gait and that Gait analysis was able to assess restoration of biomechanics after hip replacement.  I would chose to use the word “change” over restore, since the gait analysis is merely showing the deployed strategies and compensations, never the problem.  But it is a tool, and gait analysis can be a decent tool to show “change”.*Remember, it is not always a product of true length, it can come from the pelvis posturing and/or from the acetabular orrientation, which can be a postoperative sequella. One cannot over look  acetabular inclination, anteversion and femoral component anteversion/retroversion issues.Just remember, before you start making LLD changes with inserts, cork, orthotics etc be sure that you have restored as best as possible, pelvis-hip-spine mechanics because changes here can reflect as a mere leg length discrepancy. And it goes the other way as well, a LLD can cause those changes above.

* Just use your brain and don’t just lift the heel, give them a full sole lift. Heel lifts for this problem are newbie mistakes. Don’t be a newbie.

- Dr. Shawn Allen

Leg length and offset differences above 5 mm after total hip arthroplasty are associated with altered gait kinematicsTobias Renkawitz, Tim Weber, Silvia Dullien, Michael Woerner, Sebastian Dendorfer, Joachim Grifka,Markus Weber
http://www.gaitposture.com/article/S0966-6362(16)30148-5/abstract?platform=hootsuite

Forefoot strike running: Do you have enough calf muscle endurance to do it without a cost ?

Below you will find an article on footwear and running. Rice et al concluded that 

“ When running in a standard shoe, peak resultant and component instantaneous loadrates were similar between footstrike patterns. However, loadrates were lower when running in minimal shoes with a FFS (forefoot strike), compared with running in standard shoes with either foot strike. Therefore, it appears that footwear alters the loadrates during running, even with similar foot strike patterns.

They concluded that footwear alters the load rates during running. No brain surgery here. But that is not the point I want to discuss today. Foot strike matters. Shoes matter. And pairing the foot type and your strike patterns of mental choice, or out of natural choice, is critical. For example, you are not likely (hopefully) to choose a HOKA shoe if you are a forefoot striker. The problem is, novice runners are not likely to have a clue about this, especially if they are fashonistas about their reasoning behind shoe purchases. Most serious runners do not care about the look/color of the shoe. This is serious business to them and they know it is just a 2-3 months in the shoe, depending on their mileage. But, pairing the foot type, foot strike pattern and shoe anatomy is a bit of a science and an art. I will just mention our National Shoe Fit Certification program here if you want to get deeper into that science and art. (Beware, this is not a course for the feint of heart.)

However, I just wanted to approach a theoretical topic today, playing off of the “Forefoot strike” methodology mentioned in the article today.  I see this often in my practice, I know Ivo does as well. The issue can be one of insufficient endurance and top end strength (top end ankle plantar flexion) of the posterior mechanism, the gastrocsoleus-achilles complex. If your calf complex starts to fatigue and you are forefoot striker, the heel will begin to drop, and sometimes abruptly right after forefoot load. The posterior compartment is a great spring loading mechanism and can be used effectively in many runners, the question is, if you fatigue your’s beyond what is safe and effective are you going to pay a price ? This heel drop can put a sudden unexpected and possibly excessive load into the posterior compartment and achilles. This act will move you into more relative dorsiflexion, this will also likely start abrupt loading the calf-achilles eccentrically. IF you have not trained this compartment for eccentric loads, your achilles may begin to call you out angrily. Can you control the heel decent sufficiently to use the stored energy efficiently and effectively? Or will you be a casualty?  This drop if uncontrolled or excessive may also start to cause some heel counter slippage at the back of the shoe, friction is never a good thing between skin and shoe. This may cause some insertional tendonitis or achilles proper hypertrophy or adaptive thickening. This may cause some knee extension when the knee should not be extending. This may cause some pelvis drop, a lateral foot weight bear shift and supination tendencies, some patellofemoral compression, anterior meniscofemoral compression/impingement, altered arm swing etc.  You catch my drift. Simply put, an endurance challenged posterior compartment, one that may not express its problem until the latter miles, is something to be aware of. 

Imagine being a forefoot striker and 6 miles into a run your calf starts to fatigue. That forefoot strike now becomes a potential liability. We like, when possible, a mid foot strike. This avoids heel strike, avoids the problems above, and is still a highly effective running strike pattern. Think about this, if you are a forefoot striker and yet you still feel your heel touch down each step after the forefoot load, you may be experiencing some of the things I mentioned above on a low level. And, you momentarily moved backwards when you are trying to run forwards. Why not just make a subtle change towards mid foot strike, when that heel touches down after your forefoot strike, you are essentially there anyways. Think about it.

Shawn Allen, one of The Gait Guys

Footwear Matters: Influence of Footwear and Foot Strike on Loadrates During Running. Medicine & Science in Sports & Exercise:
Rice, Hannah M.; Jamison, Steve T.; Davis, Irene S.

http://journals.lww.com/acsm-msse/Abstract/publishahead/Footwear_Matters___Influence_of_Footwear_and_Foot.97456.aspx

How are your hammy’s?

Another tool for you, in addition to making sure the gluten are on line, to improve ankle rocker and hip extension.

“This study concludes that neural mobilization techniques are a useful adjunct to static stretching, without any risk of adverse events or injuries. Athletes or trainers can consider using one or both types of neural mobilization techniques to enhance muscular flexibility. Dosage of the neural mobilization as well as the proposed working mechanism behind the increase in hamstring flexibility can be found in the full text of the article.”

http://www.ncbi.nlm.nih.gov/pubmed/26482098

Phys Ther Sport. 2016 Jan;17:30-7. doi: 10.1016/j.ptsp.2015.03.003. Epub 2015 Mar 17.
Short term effectiveness of neural sliders and neural tensioners as an adjunct to static stretching of hamstrings on knee extension angle in healthy individuals: A randomized controlled trial.
Sharma S, Balthillaya G2, Rao R, Mani R .

Improve Your Running Form With A DIY Analysis - Triathlete.com→

You’re either part of the solution or part of the problem. Read and you decide if this kind of advice is actually helping people. We know what we think.

After all, everyone should fit the same mold right?
And, altering what you are doing fixes the problem right?
It must finally be time for Ivo and I to retire. Someone just build the DIY App for 2.99 and make all the running problems in the world go away. After all, truly “FIXING foot strike is relatively simple”. Clearly Ivo and I just enjoy making things terribly complex because we have nothing better to do.
To be fair to this author, There is a reason why we stopped writing for venues, because everything got so cooked down by the editorial staff until our stuff said nothing , or worse yet, simplified things so much that a monkey could do it, that we said, “ thanks, but we will take a pass on the next one”.
Oy vey. Feeling saucy tonight.
Reader beware.

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

Everything you wanted to know about the lumbricals, in less than 2 minutes.

One point and 1 treatment can profoundly influence gait

When talking about the lower extremity and gait (as I have been know to do at more that one seminar), I often talk about the “reverse engineering” principle. This is looking at a muscle or muscle group from a “ground up” perspective, as it would be functioning during the gait cycle. This, along with knowing when a muscle should be firing in the gait cycle, can provide clues to what may be going on and how you may be able to help.

When discussing the quads, we often employ this principle. It can be a little difficult to think of the vastus medialis as a lateral rotator of the thigh and the rectus femoris as a flexor (anterior nutator) of the pelvis, but if you put your foot on the ground and think about it, you will see what I mean.

The VMO is often implicated in patello femoral syndromes but cannot be selectively activated. The ratio between vastus medialis and vastus lateralis does seem to be alterable and perhaps is a siginificant factor.

How about if we look at the vastus lateralis instead?

The vastus lateralis is the largest and most powerful portion of the quadriceps. One paper reports that the muscle volume of the the vastus lateralis was 674 cm3 followed by the vastus intermedius at 580 cm3, vastus medialis 461 cm3 and lowest in the rectus femoris 339 cm3.  This makes the vastus lateralis is twice the volume of the rectus femoris!

Studies of muscle fiber orientation show that VL force component is directed approximately 12-15° laterally with respect to the longitudinal axis of the femoral shaft. This would mean it has a tremendous mechanical advantage and could (should?) pull the patella directly laterally compared to the VMO force, whose component is directed approximately 55 ° medially.   The muscle “balance” between the VMO and the VL, along with the periarticular soft tissue structures acting on the patella, is considered major component in the control of normal patellar alignment and function. The VL is often considered to be the “overactive” one by many clinicians, particularly in cases of patellofemoral dysfunction. It turns out that from an EMG standpoint, they may be correct. 

The vastus lateralis arises posteriorly from the femur along the linea aspera and circumnavigates the thigh in a counterclockwise fashion to attach laterally to the patellar tendon.   Because of its size and fiber orientation, it would stand to reason that needling it would have more cortical representation than say the vastus medialis.

There is an interesting paper where they needled a single acupuncture point: Stomach 34. For those who haven’t studied acupuncture (or don’t remember) this point is located on the thigh, in a small depression about 2.5 inches (63 mm for the metric folks) lateral to and above lateral border of the patella. In other words, it is in the vastus lateralis (see above).

The results showed statistically significant improvement in velocity, cadence, stride length, cycle time, step time and single/double leg support after treatment. The effect was small, but positive.

Think about where the trigger points are for this muscle (see above) ; fairly close to this point, sometimes (depending on the trigger point), even directly over this point. Needling has many effects on muscle and its trigger points and we like to think that needling “normalizes” function of a muscle; perhaps it influences the apparent “dominance” of this muscle and allows the patella to track more medially?

So, in this popultion of patients of elderly individuals, 1 acupuncture (needling) treatment  had a positive influence on their gait. Perhaps if the folks in the knee study were treated a few more times, we would have seen a change. Imagine what could have happened if aditional treatment modalities, like exercise, proprioceptive work and gait retraining were added! 

What a great, cost effective alternative or addition to your rehabilitation this could be. Consider adding this modality (and point!) to your current clinical toolbox, not only for older patients but for any patients that may have a gait abnormality.

https://tmblr.co/ZrRYjx24ecKUx

Boucher JP, King MA, Lefebvre R, Pépin A. “Quadriceps femoris muscle activity in patellofemoral pain syndrome.” Am J Sports Med. 1992 Sep-Oct;20(5):527-32. Web. 17 Nov 2012.

Souza DR, Gross MT. “Comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patellofemoral pain.” Phys Ther. 1991 Apr;71(4):310-6. Web. 25 Nov 2012.

Cowan SM, Bennell KL, Crossley KM, Hodges PW, McConnell J. “Physical therapy alters recruitment of the vasti in patellofemoral pain syndrome.” Med Sci Sports Exerc. 2002 Dec;34(12):1879-85. Web. 26 Nov 2012.

Boling MC, Bolgla LA, Mattacola CG, Uhl TL, Hosey RG. “Outcomes of a weight-bearing rehabilitation program for patients diagnosed with patellofemoral pain syndrome.” Arch Phys Med Rehabil. 2006 Nov;87(11):1428-35

Kim, H. H., & Song, C. H. (2010). Effects of knee and foot position on EMGactivity and ratio of the vastus medialis oblique and vastus lateralis during squatexercise. Journal of Muscle and Joint Health, 17(2), 142-150.

Lam, P. L., & Ng, G. Y. (2001). Activation of the quadriceps muscle during semisquatting with different hip and knee positions in patients with anterior knee pain. American Journal of Physical Medicine & Rehabilitation, 80(11), 804-808.

Erskine, R. M., Jones, D. A., Maganaris, C. N., & Degens, H. (2009). In vivo specific tension of the human quadriceps muscle. European journal of applied physiology, 106(6), 827-838. [PubMed]

Grabiner MD: Current Issues in Biomechanics (9th ed). Champaign, Human Kinetics Publishers, 1993.

http://www.orthobullets.com/anatomy/10058/vastus-lateralis

Hauer K, Wendt I, Schwenk M, Rohr C, Oster P, Greten J. Stimulation of acupoint ST-34 acutely improves gait performance in geriatric patients during rehabilitation: A randomized controlled trial. Arch Phys Med Rehabil. 2011 Jan;92(1):7-14. doi: 10.1016/j.apmr.2010.09.023.

Peter Deadman, Mazin Al-Khafaji, Kevin Baker: A Manual of Acupuncture (2nd Edition) Journal of Chinese Medicine Esat Sussex, England 2007

Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual: The Lower Extremities. Vol.2 . Baltimore, Md: Williams & Wilkins;1992

 http://www.medscape.org/viewarticle/521494_3

New research on Non-motorized treadmills.

Facts:

•Non-motorised treadmill locomotion creates large reductions in tibial acceleration.
•Non-motorised treadmill locomotion increases lower limb muscular activation.
•Non-motorised treadmill locomotion decreases cycle time/increases step frequency.

Keep these things in mind when you are doing a treadmill gait analysis. We have discussed over and over again of the severe and misleading information gleaned from gait analysis, that it shows strategies around problems, often not the problem at hand. But, this is yet one more factor to keep in mind when you are doing such studies, that changing the surface and how and why any given work is being performed on a given surface/device, that the information can be tainted if you do not know exactly what you are dealing with.   

Few studies are perfect, look at all of the parameters they likely should, and understand the complexity of the model they examine in their entirety. None the less, there is information to glean from most studies that help to debate, refute or clarify working concepts presently proven or unproven. This study provides some conclusions as well, that should be take in, digested and then determined where, when and if appropriate for a client.

Tibial impacts and muscle activation during walking, jogging and running when performed overground, and on motorised and non-motorised treadmills

Montgomery, Dobson, Smith & Ditroilo

http://www.gaitposture.com/article/S0966-6362(16)30116-3/abstract?platform=hootsuite

A clear cut case of Form follows Function.  Leave a deforming force long enough and the body will accommodate. 

When the lateral quadratus plantae (QP) is weak and the flexor digitorum longus pulls unopposed (relying on the QP to properly orient the long flexor pull) for too long the 4th and 5th toes and drift medially and spin inwards toward the midline of the foot (as seen in the photo). Then, as the 4th toe presses down on the fleshy pad of the 5th toe, over time the fleshy pad is pancaked and triangulated. Then, with repeated pressure a corn like hardness becomes of the tip of that triangluted tissue, it resembles a hard callus. A corn is a coalescing of the skin cells into a tighter formation, a reaction to fend off repeated pressure and friction.  Form follows prolonged function.  Shave these things down and they will come back, unless you get to the root source of the problem, which could be all the way up the chain. 

-Dr. Allen

A marathon a day, for over 120 days…..on one leg, battling cancer.

So you think you are tough ? This guy was tough. A marathon a day for over 120 days…..on one leg, battling cancer. 

Rest in Peace Terry. You are not forgotten. You made a mark on my life, thank you for that. Watching you skip on the good leg, giving your prosthetic enough time to swing through mesmerized me, the biomechanics of it all. If i look back, this was the first time I payed attention with great detail to someone’s gait. I was in awe, you moved me, your mission moved me, your heart and spirit moved me. Your life made a difference in mine, so I may help others.Dr. Allen
Today, June 28th, every year here on The Gait Guys, I remember Terry Fox. Every year I post a reminder of perhaps one of the toughest dudes who ever lived. Today , this day, 1981 Terry Fox died. I grew up in Canada. I was barely a teenager when Terry began his plight, The Marathon of Hope. 

His mission, 26 miles a day, every day, until he had crossed the expanse of Canada to raise awareness for cancer. He made it an amazing 120+ days in a row, 3339 miles, one one leg, before his cancer returned. The whole country stood cheering watching him do something no mortal man would attempt, let along with one leg, and cancer. Today we pay a tribute to this true rockstar.
Let this video move you, just in case you think you are having a rough day.

https://www.youtube.com/watch?v=xjgTlCTluPA

Global body compensations in ACL deficient knees.

ALERT: Ok, this is big.
It is a huge comment on what the brain and reflexive patterns impart on posture and gait when perceived functional instability is present.
This study aimed to investigate the gait modification strategies of trunk over right stance phase in patients with right anterior cruciate ligament deficiency.
* Here is what you need to ABSOLUTLY keep in mind when you read it. The 3D capture it telling you what they are DOING to strategize, not what is WRONG or what needs CORRECTING (our mantra it seems, sorry to keep beating this concept to death). This again hits home what I have been preaching for quite some time, that arm swing (and you can translate that to trunk movements, thorax, head posture, breathing etc) should not be coached or corrected unless you are absolutely sure there are clean symmetrical lower limb biomechanics (yes, you can easily and correctly argue that you can concurrently work on all parts). IF there is something going awry in a lower limb, compensations will occur above, they have to occur. So be absolutely sure you are not making therapeutic interventions above without making therapeutic corrections below. If you are working on a shoulder/upper quarter problem and are not looking for drivers in the lower limbs or in gait, well … . . good luck making lasting effects. Other than breathing, it can be argued well that gait locomotion is our 2nd most engaged motor pattern that we have driven to subconscious levels , and compensations are abound (but not without a cost), so we can dual++ task.
If you want to dive deeper into this, search our blog and look for my articles on Anti-phasic gait. This is essentially what this study was looking at, and confirming, that there is a distortion in the NORMAL opposite phase movements (anti-phasic) of the “shoulder girdle” and “pelvic girdle” when something goes wrong in a lower limb.
- Dr. Allen

Findings from Shi et al when there was a chronic right ACL deficiency:
-trunk rotation with right shoulder trailing over the right stance phase was lower in all five motion patterns
- trunk posterior lean was higher from descending stairs to walking when the knee sagittal plane moment ended
- trunk lateral flexion to the left was higher when ascending stairs at the start of right knee coronal plane moment when descending stairs at the maximal knee coronal plane moment and when descending stairs at the end of the knee coronal plane moment
- trunk rotation with right shoulder forward was higher at the minimal knee transverse plane moment and when the knee transverse plane moment ended
- during walking, trunk rotation with right shoulder trailing was lower at other knee moments during other walking patterns

http://www.ncbi.nlm.nih.gov/pubmed/27131179

Feature: Arterial disease and cycling - VeloNews.com→

“That offseason, his symptoms worsened. Before, it might have taken 20 minutes of riding at 400 watts to feel the sensation. Now, if he rode for five minutes at 350, he’d be riding with one good leg and one numb, powerless appendage.”

Iliac artery endofibrosis is a circulatory condition affecting the legs and is sending more and more cyclists under the knife.
If you are a bike geek like i am (been watching the Tour de France since i was 15) you may take interest in this. If you are a avid bike rider or triathlete you may take interest in this.
But do not stop at the bike when you have symptoms in front of you that sound vascular. If your leg is doing numb on a long walk or run, dead or heavy during exertion, something is going on that needs evaluated. Get evaluated.

Obesity and Base of Support

Recently we have been speaking and writing about “base of support” and how a narrow base of support will render a small comfort and control zone of balance in single leg tasking (walking, running, sports etc). We do not notice these things if we are standing on both feet or when walking or running per se, but all one needs to do is test a 30 second single leg stance to see how crappy one’s single limb base of support actually is. Most people will drift the pelvis laterally to get the single foot under the center of the body mass. This is a false support, it is a demonstration of weak support, unless you like to walk on a line/cross over gait. We should not have our knees rubbing together, scuffing our ankles or shoes together. If you do, you have a narrow base of support, have engrained a lazy style of locomotion, and you will wish and attempt to put the center of your body mass over the foot at all times. This is good if you are walking on ice, but that is about it. This is an epidemic, hence the prevalence of cross over gait out in the world. Increasing balance ability will help to increase base of support and hence help with reducing cross over gait (narrow step width gait and running) tendencies. Obesity seems to make this worse. Obesity in our world is wrecking our people, especially our kids.

“Alterations were detected in the intermittent postural control in obese children. According to the results obtained, active anticipatory control produces higher center of pressure displacement responses in obese children and the periods during which balance is maintained by passive control and reflex mechanisms are of shorter duration.”
“Differences in intermittent postural control between normal-weight and obese children ” Israel Villarrasa-Sapiña, Xavier García-Massó

http://www.gaitposture.com/article/S0966-6362(16)30091-1/abstract?platform=hootsuite

Kinetic chain transfer.

Anyone would be silly to disagree with this.
We go into some deeper reasoning back in this older blog post (https://tmblr.co/ZrRYjxTJ6zw9) looking at arm swing and leg swing and pairing of pelvis and shoulder posturing and how clean pelvis function parlays into upper body function in softball pitching.

“Proper utilization of the kinetic chain allows for efficient kinetic energy transfer from the proximal segments to the distal segments. Dysfunction at a proximal segment may lead to altered energy transfer and dysfunction at more distal segments,”

Lower body conditioning may cut upper body injury risk in softball. -Hank Black

http://lermagazine.com/special-section/pediatric-clinical-news/lower-body-conditioning-may-cut-upper-body-injury-risk-in-softball

Gait and Autism spectrum disorder (ASD).

Gait and autism spectrum disorder (ASD):
“ … overall findings of the studies conducted in the area are inconclusive … however, some results suggest an emerging pattern. The current perspective on gait patterns in children with ASD is that there are a number of deviations present in terms of temporospatial, kinematic, and kinetic parameters and that gait, along with other movement pattern changes, may be used to allow for earlier diagnosis of ASD. There is, however, some consensus regarding the involvement of the cerebellum and basal ganglia in children with ASD and the relationship with observed motor deficits. ” - Kindregan et al

http://www.hindawi.com/journals/aurt/2015/741480/

Gait and the lower visual field.

Gait and the eyes. We forget about the eyes. If you have vision issues, your gait may change.
Gaze during adaptive gait involving obstacle crossing is typically directed two or more steps ahead where as visual information of the “in the moment” swinging lower-limb and its relative position during the task is available in the lower visual field. This study determined exactly when visual information is utilised to control/update lead-limb swing trajectory during obstacle negotiation.
In this study, when the lower visual field was blocked out the foot-placement distance and toe-clearance became significantly increased, suggesting the brain overcorrecting for safety. A logical assumption. “These findings suggest that lower visual field input is typically used in an online manner to control/update final foot-placement, and that without such control, uncertainty regarding foot placement causes toe-clearance to be increased.”

http://www.ncbi.nlm.nih.gov/pubmed/22424759

Base of support and chronic ankle sprains

We spoke at length about “base of support” and how if you have a narrow base of support, you have a small comfort zone of balance in single leg tasking (walking, running, sports etc). If you have a narrow base of support, you will wish and attempt to put the center of your body mass over the foot at all times…….hence the cross over gait often times. Increasing balance ability will help to increase base of support and hence help with reducing cross over gait (narrow step width gait and running) tendencies.
* This study here showed that a SINGLE episode of single 30-minute training session involving kicking a ball while standing on 1 foot promoted changes in postural-control strategies in individuals with chronic ankle instabilty(CAI).
Does this translate to the assumption that “CAI clients will have a narrow step width, narrow base of support, and a cross over gait”? No, but if you are thinking that way, we want you on our team.

Changes in Postural Control After a Ball-Kicking Balance Exercise in Individuals With Chronic Ankle Instability. Marcio Jose dos Santos PhD, Josilene Conceição PT, MSc, Felipe Gustavo Schaefer de Araújo, Gilmar Moraes SantosPhD, John Keighley PhD