Exploring the Links Between Human Movement, Biomechanics & Gait
Medial knee pain in a skier. Considering an orthotic? You had better know what you are doing!
Can you guess why this gal has pain in both knees? Especially when skinning up a hill and skiing down?
Take a close look at the photos above and notice the orientation of her knee with her foot. Now look at you tuberosity and drop a line straight downward. This line should pass through or slightly lateral to the second metatarsal shaft. Can you see how it falls to the outside of this? Perhaps even between the third and fourth metatarsal?
This gal has bilateral internal tibial torsion. When she wears a standard foot bed (creates a level surface for the right for the foot) or an orthotic without appropriate posting, it pushes her knee outside of the saggital plane. This creates abnormal patellofemoral tracking and appears to be a major contributor to her pain.
You will notice that we placed a valgus post under the orthotic( a post that is canted from lateral to medial) which pushes her knee to the midline as the first ray descends. You can see her alignment is better with her boots on and the changes.
The bottom line? Know your torsions and versions. Posting a patient like this incorrectly could result in a meniscal disaster!
No, this is not a post about fractures phalanges, but rather where your shoe bends, or should bend.
Toe break is where the shoe bends anteriorly. Ideally, we believe this to be at the 1st metatarsal phalangeal joint and metartarsal phalangeal articulations. This allows for the best “high gear” push off as described by Bojsen-Moller (1) High gear push off means that the pressure goes to the base of the great toe (1st MTP joint) for push off. (for an interesting post on this, see here .
If we think about rockers of the foot during the gait cycle (need a review? click here), it seems best that we accommodate each of them to the best of our abilities. Since most of us wear shoes, it would make sense that it flex in the right places. With regards to the forefoot, it should (theoretically) be under the 1st metatarsal phalangeal joint. This should provide both optimal biomechanical function (distribution of force to the 1st metatarsal phalangeal joint for push off/ terminal stance) and maximal perceived comfort (2).
If the shoe bends in the wrong place, or DOES NOT bend (ie, the last is too rigid, like a rockered hiking shoe, Dansko clog, etc), the mechanics change. This has biomechanical consequences and may result in discomfort or injury.
If the axis of motion for the 1st metatarsal phalangeal joint is moved posteriorly, to behind (rather than under) the joint, the plantar pressures increase at MTP’s 4-5 and decrease at the medial mid foot. If moved even further posteriorly, the plantar pressures, and contact time in the mid foot and hind foot (3). A rocker bottom shoe would also reduce the plantar pressures in the medial and central forefoot as well (4). It would stand to reason that this would alter gait mechanics, and decrease mechanical efficiency. That can be a good thing or a bad thing, depending on what you are trying to accomplish.
Take home messages:
Where a shoe flexes will, in part, determine plantar pressures
Changes in shoe flex points can alter gait mechanics
More efficient “toe off” will come from a shoe flexing at the 1st metatarsal phalangeal joint and across the lesser metatarsal phalangeal joints
examine the “toe break” in your clients shoes, especially of they have a foot problem
1. F Bojsen-Møller Calcaneocuboid joint and stability of the longitudinal arch of the foot at high and low gear push off. J Anat. 1979 Aug; 129(Pt 1): 165–176.
4. Schaff P, Cavanagh P Shoes for the Insensitive Foot: The Effect of a “Rocker Bottom” Shoe Modification on Plantar Pressure Distribution Foot & Ankle International December 1990 vol. 11 no. 3 129-140
plantar pressure image above from : Dawber D., Bristow I. and Mooney J. (1996) “The foot: problems in podiatry and dermatology”, London Martin Dunitz Medical Pocket Books.
With all the talk on the Crossfit blog about the knees out debate, we though we would shed some light on measuring torsions, beginning with tibial torsion, since this does not seem to have been taken account of in the discussion and we feel it is germane.
Yo may have seen some of our other posts in tibial torsion here or here; this post will serve to help you measure it.
Looking at the top left picture: we can see that the axis of the tibial plateau and the transmalleolar axis (an imaginary line drawn through the medial and lateral malleolus) are parallel at birth (net angle zero) and progress to 22 degrees at skeletal maturity, resulting from the outward rotation of the tibia of about 1-1.5 degrees per year. This results in a normal external tibial version of about 17-18 degrees (you subtract 5 degrees for the talar neck angle, talked about in the link above). Note that this is the normal or ideal angle we would expect (hope?) to see. Go 2 standard deviations in either direction and we have external and internal tibial torsions.
You can go about taking this measurement in may ways; we will outline 2 of them.
In the upper left picture, we see an individual who has their knee flexed to 90 degrees over the side of a table while seated. This represents the tibial plateau angle. You the use a protractor to measure the angle between the tibial plateau and an imaginary line drawn through the medial and lateral malleoli. This is the transmalleolar angle. You then subtract 5 degrees from this number (remember the talar neck angle?) to get the angle of tibial version (or torsion).
In the lower left and right pictures, we have the patient supine with the knees pointed upward and tibial plateau flat on the table. Then, working from inferiorly, use a goniometer to measure the angle of the transmalleolar axis. Again, we subtract 5 degrees for the talar neck.
We would encourage you to read up on torsions. This post, which we wrote over a year ago, is probably one of the most important ones on tibial torsions.
Torsions. Important stuff, especially when you are talking about the axis of the knees in activities like a squat. Remember, the knee is a hinge between 2 multiaxial joints (hip and ankle) and will often take the brunt of the (patho)mechanics, as it has fewer degrees of freedom of movement. If you have external tibial torsion and you push your knees (angle your feet) out further, you are moving the knees outside the saggital plane. You have better have a very competent medial tripod! If you have internal tibial torsion, angling the feet out may be a good idea. Know your (or your patients/clients/athletes) anatomy!
The Gait Guys. Bald, Good Looking and Twisted. Here to help you navigate your way through better biomechanics.
Whether you ski, ride, nordic or tele, having the right boot fit can make the difference between a good day and a great day. It can accelerate your learning curve, prevent injuries, keep you warm and make you more comfortable. Not all feet are made the same and neither are ski boots. Good fit requires time and patience (lots of both). Here are a few tips for better fit.
What kind of a skier/rider are you? Recreational, competitive, racing, extreme? How you’ll use the boot will often determine the type of boot that is appropriate for you. In my opinion, you should get a boot that is a little above your ability (unless you are not interested in improving your skiing and/or riding), so that you will improve and “grow into” the boot. This will ensure that you’ll continue to improve in your snowriding abilities. Boots are very high tech these days and a subtle change in stiffness or angles can make a drastic difference in your skiing/riding.
The first thing you need to do is look at your feet. Are they feet to the same from side to side (ie. same size and shape)? These are the platform for the rest of your body. What happens down there will affect everything else. Take a good look at your feet while you are standing. Are there bunions, calluses, hammertoes (toes curled under), or a Morton’s toe (2nd toe longer than your big toe)? Do you pronate excessively while standing or walking (this will look like your arches are collapsing)? What is the relationship of the forefoot (front of your foot) to the rear foot (is the ankle sideways when viewed from behind? It should be neutral without your heel turning in (inversion) or turning out (eversion). The forefoot (front of your foot) should be flat on the ground. Does your ankle bend back as far as it should (this is called dorsiflexion). This will have an effect on the forward lean of the boot. Are you bowlegged or knock-kneed? This will cause you to ride on the outside or inside edge of your ski/ snowboard.
If you pronate excessively, have increased or decreased flexibility in the forefoot, rearfoot or big toe, have bunions or hammertoes, or are excessively bowlegged or knock kneed, proper fit and comfort while skiing will probably require a full contact orthotic or footbed. Hard deformities, such as bunions, may require liner and or boot shell modification.
Good socks are next on the list. Wool or wool blend socks are best. The intertwining fibers of wool create air pockets, which make it both insulating and breathable. Wool absorbs sweat in its vapor state, before it liquefies, keeping you dry. It utilizes your own body heat to evaporate the moisture. This also helps to eliminate odor. No cotton socks, as they hold moisture, often creating blisters and providing a breeding ground for bacteria that cause odor; no multiple pairs, as they make feet cold. Remember, thin is in… let the liner do its job.
Have your foot measured utilizing a Brannocks device in a standing position. Remember that your arch will flatten as you put weight on it. Remembering that the foot elongates with weight on it, will be useful for the next step.
Next you need to have the right sized ski/snowboard boot shell. This is as important for hard boots as soft boots Take the liner out of the boot and put your foot inside the shell so that your toes are just touching the front of the shell. There should be approximately ½ – ⅝ of an inch (two crossed fingers thickness) behind the ankle to the back of the shell. More than ¾ of an inch will cause too much heel rise once the shells are “packed out”. There should be ¼ – ⅜ of an inch space between the feet and the side shell of the ski boot.
Now comes the liner. The liner should fit snugly. Very snugly. There should be no pressure spots anywhere on your foot. Put in your foot bed or custom orthotic if available, before sizing the shell. Remember that you’ll gain between ⅛ and ¼ of an inch of space with break-in when the liners “pack out”.
Buckle the boots loosely and flex the boot forward. This will help to “seat the heel”. Remember that if the you cannot flex the boot at room temperature, you will not be able to when the plastic is very cold. Now that the heel is seated, buckle the boot more firmly. They should not be on the last buckle.
Now simulate some ski/ride movements. If the boot is relatively comfortable, proceed to the next step otherwise repeat with different shell/liner size.
The cant of the boot (cuff alignment) needs to be adjusted next. This needs to be done by someone other than yourself (because you are standing in the boot). A plumb line dropped from the knee should pass between your second and third toe. This ensures an even transfer of weight from edge to edge. Most boots are built with about 4 degrees of varus (lateral cant). If you are not able to adequately align the foot, consider orthotics or having the boot shimmed. Remember that boots with higher cuffs will have more of an effect on your stance.
Most boots provide between 12-16 degrees of forward lean. If there is less than 12 degrees, consider a heel lift to place your body weight forward. Remember to consider how much ankle dorsiflexion you have.
Once these adjustments are made, simulate skiing/riding movements in the shop for at least an hour. Remember that ski/snowboard boots are made for snowriding, not walking. Now remove the boots and socks and look for “hot spots” on the feet that will show up as red marks. These may represent areas in the boot liner or shell that need to be stretched and/or fitted better.
Well. There you have it. Now you know lots more than you knew when you began this article. As you can see, it is a very time consuming and labor intensive ordeal. Often times, people need professional help with the whole process and often require a foot bed or full arch contact orthotic. Become familiar with your own feet and then become familiar with the people or shops that do good boot fitting (ask around) and consider enlisting their help on your journey to the perfect boot.
The Gait Guys. Making it real…here….on the blog…with every post…
Take a good look at these shoes. Notice the wear at the heel counter. Did you notice the varus cantof the rear foot. Good! Did you carefully inspect where the upper was attached to the midsole? Now did you notice that upper is canted in varus as well? This person DID NOT have a rear (or forefoot) varus.
Hmmm. Maybe the varus canting of the upper caused the wear on the outsole? We doubt it; most likely it was the other way around.
What sort of symptoms so you think they had?
Do you think medial or lateral knee pain?
Could be either.
Lateral; knee pain from stretch on the lateral side of the knee at the lateral collateral ligament or
medial from compression of the medial condle of the femur and medial tiibial plateau.
How about pain on the outside of the hip? Canting the foot laterally has a tendency to externally rotate the lower leg and thigh. This may cause shortening of the gluteals (max and post fibers of the min); difficulty accessing the gluteus minimus (its a medial rotator), shortening of the deep 6 external rotators, difficulty accessing the vastus medialis (external rotator when foot is on the ground), and the list goes on.
What’s the fix?
New shoes. Pay attention when you buy shoes. Put them up on a counter at eye level and inspet them closely. We can’t tell you how many defects we see on a daily basis; too many to count. One time at a shop, we needed to go through 10 pair before we had a good right and left.
The Gait Guys. Bald. Good looking. Smart. Increasing your “Shoe IQ” every day.
Want to know more? Take our National Shoe Fit Certification Program. It’s the only one of its type and the only one certified by the International Footwear and Gait Education Council. Drop us an email at: email@example.com for more details or go to our payloadz store (click here) and download it today.
All material copyright 2013 The Gait Guys/ The Homunculus Group.
“With more than 2 decades in the fitness industry, and a MS in Exercise Physiology, I’ve learned that there is so little that I really know. I am constantly looking to improve what I can do to help the triathletes and runners that I see. As an endurance coach and clinician that focuses on preventing injuries, optimizing performance, and avoiding reoccurring injuries, the IFGEC Shoe Fit Certification is going to be a keystone (much like the Navicular Bone) to my screening process of athletes and clients. Making sure they are fitted properly in shoes, working with their movement patterns, teaching them running form skills, and then building on all aspects from there. What I have learned from “The Gait Guys” has already made an impact on what I do, but it’s at a whole new level now. This is not just a “online course” this is real education that stays with you for life. This is a true Ground Up approach to helping and is something that every running shoe store, coach, and medical professional that deals with runners and triathletes needs to learn.”
Ryan Smith, MS is owner of the Personal Impact, LLC and The Runners’ Clinic in the Cincinnati, Ohio area. He is a USATF Level 1 Coach, Newton Natural Running Form Coach, & ACSM-CPT that works with runners and triathletes helping to prevent and recover from injuries that athletes deal with. More information on Ryan Smith, visit his site at. http://ryansmithfitness.com
Want to get certified or learn more? Email us at firstname.lastname@example.org
More to say about the National Shoe Fit Certification Program…
“I found the course to be the perfect blend between science and retail practices, making it an essential tool for any specialty running store. Immediately after finishing the video I was able to recognize specific issues in my customer’s feet and their reaction to my knowledge couldn’t have been more positive. As a result of becoming certified I will have happier and healthier customers and will know when to refer particular foot and gait issues to my partner doctors and physical therapists. The video will be a resource long after becoming certified.”
Ben Nelson is the manager of Goldstream Running, the farthest north run specialty shop in North America (and maybe the world!), located in the Goldstream Valley outside of Fairbanks, Alaska. He also coaches high school cross country and track and field.
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