ski boots

FIT VS. FUNCTION

With rare exceptions, the consistently stated objective of boot-fitting systems and modification efforts is to create a perfect fit of the foot and leg of a skier with the rigid shell of a ski boot by applying uniform force to the entire surface of the foot and the portion of the leg in the boot in what pits Fit against Function. The end objective of the Perfect Fit is to achieve a secure connection of the leg of the skier with the ski. In the name of achieving a secure connection of the foot with the ski, the function of the skiers’ foot has become unitended collateral damage.

But boot design and boot fitting effors didn’t start off with the intent of compromising the physiologic function of the foot. It just sort of happened as a consequence of the limited ability to change the shape of the rigid plastic ski boots to address issues of user discomfort when plastic boots were first introduced. The new plastic boots worked well for some skiers. But for most, myself included, my foot moved around inside the shell when I tried to ski. The feeling of insecurity created by the looseness made skiing with any semblance of balance or control impossible. The fix seemed to be a simple matter of trying to figure out where to place a pad or pads between the foot and shell to stop the foot from moving.

In 1973 when I first started tinkering with my own ski boots the craft of boot fitting barely existed. Like myself, those who were trying to solve the problem of a loose fit were doing proceeding by trial mostly with alot of errors. After what seemed like unending frustration from many failed attempts at trying to find and then solve the source of my loose fit, a consensus began to emerge within the ranks of the ski industry that the easiest and quickest solution was a process that would create a tight fit of the foot everywhere with the boot instead of wasting time trying to find the elusive right place to add pads. The Perfect Fit was born.

Injected foam fit was first off the mark as a Perfect Fit solution. But injected foam fit wasn’t tight or precise enough for my standards. So I tried to take the Perfect Fit to the next level with Crazy Canuck, Dave Murray. I started the process by carefully trimming and laminating together pieces of sheet vinyl to form a matrix of solid material that I inserted into the liners of Mur’s boots. The process took about 2 weeks of painstaking effort. Finally, I satisfied that Mur’s feet were securely locked and loaded; ready for the best turns of his life. The result? One of the world’s best racers was instantly reduced to a struggling beginner, the exact opposite of what I had expected! This experience served as a wakeup call for me; one that caused me to rethink what I thought I knew and question whether the Perfect Fit was the best approach or even the right approach.

I started looking for alternate ways to restrain the foot so it was secure in the shell of a ski boot without compromising foot function. In 1980 when I was building a pair of race boots for Crazy Canuck, Steve Podborski I literally put my finger on the solution when I pressed firmly, but not forcefully, on the instep of his foot just in front of the ankle and asked if he thought we should try holding his foot like this in his new race boots. Without the slightest hesitation he said, “That feels amazing. Let’s do it!”

It took me more several few days to fabricate a system to secure Pod’s foot in his boots by loading the area of the instep that I had pressed my finger on. The problem we faced when the system was finished was that the liner made it impossible to use the system without modifying it. So a decision was made to eliminate the liner except for the cuff portion around the sides and back of his leg which I riveted to shell. At the time I wasn’t sure the system would even work. So I made a pair of boots with fined tuned conventional fit as backup. A boot with no liner seemed like an insane idea. But Podborski was not only able to immediately dominate his competition on the most difficult downhill courses on the World Cup circuit but go on to become the first non-European to win the World Cup Downhill title. Even more remarkable is that in his first season on the new system he was able to compete and win less than 4 months after reconstructive ACL surgery.

What I discovered set me off in a whole new direction. Pressing on the instep of Podborski’s foot activated what I later found out is called the Longitudinal Arch Auto-Stiffening Mechanism of the Foot. This system is normally activated as the mid stance (support) phase of walking approaches late mid stance where the foot is transformed into a rigid structure so it can apply the forces required for propulsion. As I learned about the processes that transform the foot into a rigid lever I began to understand how interfering with the function of the foot can compromise or even prevent the Longitudinal Arch Auto-Stiffening Mechanism from activating and, in doing so, cause the structures of the foot to remain ‘loose’ regardless of any efforts made to secure it.  A rigid foot is necessary to effectively apply force to a ski.

The graphic below shows a sketch on the left from Kevin Kirby, DPM’s 2017 paper, Longitudinal Arch Load-Sharing System of the Foot (1.) Figure 44 A on the right is from my 1993 US Patent 5,265,350.

The above graphics clarify the details of the arch loading system I first disclosed in my US Patent 4,534,122. This system challenges the current Perfect Fit paradigm in which the physiologic function of the foot is compromised in an effort to try and achieve a secure connection of a skier’s foot with the ski.

Figure 44A above shows the principle components of the arch loading system which is comprised of a number of complimentary elements. I will discuss these elements in my next post which will focus on solutions.


  1.  Kirby KA. Longitudinal arch load-sharing system of the foot. Rev Esp Podol. 2017 – http://dx.doi.org/10.1016/j.repod.2017.03.003

 

IN THE BEGINNING: HOW I GOT STARTED IN SKI BOOT MODIFICATIONS

I originally published this post on May 12, 2013. This is a revised and edited version.


Before I started ‘tinkering’ with ski boots in 1973, I didn’t just read everything I could find on the subject of fitting boots, I devoured every bit of information I could find on the subject. The assumption I made at that time was that the experts in the field not only knew what they were talking about, but that they also had the requisite knowledge and understanding of the underlying principles to back up their positions with applied science and/or research. Based on this assumption, I started modifying ski boots by doing all the things the experts recommended such as padding the ankle to ‘support’ and ‘stabilize’ it in the boot shell and cuff and adding cants between the soles of the boots and the skis to make the skis sit flat on the snow. But the big breakthrough for me came when I started making footbeds to support the foot.

Within a year I had gained expertise in my craft to the point that skiers from all over Canada were starting to seek out my services. In  response, I started a company called Anatomic Concepts. Soon, I was spending most of my free time working on ski boots. But while I was helping a lot of skiers ski better, none of what I was learning or doing was helping my own skiing. I was still struggling after switching from low-cut leather boots to the new stiff, all plastic boots.

The (Un)Holy Grail

Despite the inability to solve my own problems, my thinking remained aligned with conventional thinking right up until my experience with Mur and the ‘Holy Grail’ of ski boots; the perfect fit of the boot with the foot and leg of the skier.

In 1977, Roger McCarthy (head of the Whistler Ski Patrol), whose boots I had worked, on introduced me to Nancy Greene Raine in the Roundhouse on top of Whistler Mountain. The timing was perfect. Racers on our National Ski Team were having boot problems. They needed help. It was a classic case of me being in the right place at the right time. Nancy recruited me, flew me to Calgary at her expense and introduced me to the National Team and Dave Murray. She set up a working arrangement with the team, one in which I was completely independent. Nancy also introduced me to Glen Wurtele, head coach of the BC Ski Team. At Wurtele’s request, I began working on the boots of members of the team.

I started working on the boots of NAST (National Alpine Ski Team) racers with Dave Murray; ‘Mur’ as he was affectionately known. My thinking at that time vis-a-vis the need to immobilize the foot and achieve a ‘perfect fit’ of the boot with the foot was aligned with the approach of the  ‘experts’ in the  field. Mur didn’t live far from me. When I was working on his boots, he seemed to spend more time at our home than his. Because of my ready access to Mur, I saw an opportunity to achieve the Holy Grail of skiing with a fit of the boot with the foot so perfect that the foot was for all intents and purposes rendered rigid and immobile and united with the structures of the ski boot.

To achieve this lofty goal I spent the better part of 2 weeks working for hours every night carefully crafting a matrix of heat formable 1 mm thick vinyl around Mur’s foot and leg and the shells of his boots with my inserts inside the liners of the boot. When Mur finally confirmed he was ‘loaded, locked and ready’ he went skiing to test the results. I waited for the inevitable confirmation of success and certain celebration that would follow. But after what seemed like an eternity, instead of the expected good news, Mur called to tell me that he could barely ski with my perfect fit. He had little or no balance or control. The Holy Grail had reduced a world class skier to a struggling beginner. I didn’t need to be a rocket scientist to know that the industry had to be way off track especially in view of the recent publication of Professor Verne T. Inman’s seminal book, The Joints of the Ankle.

After this experience I knew that there was way more going on than I understood. I started learning about human physiology, in particular, about the mechanics, neuralbiomechanics and physics of skiing. I started asking hard questions that no one in the industry seemed to have answers for. And I started going off in a very different direction from the one the industry was acquiring increasing momentum in. If the perfect fit could impose what amounts to a severe disability on one of the world’s best skiers I could only imagine what such indiscriminate constraint was doing to the average recreational skier. It could not be good. For me it certainly wasn’t.

A major turning point came for me in 1988 when a husband and wife radiology team who had heard about my efforts to try and develop a ski boot based on anatomical principles presented me with a copy of a medical text called The Shoe in Sport published in German in 1987. This seminal work contains an entire chapter dedicated to The Ski Boot. I discuss the issues raised about the design and fabrication of ski boots by international experts in the articles in chapter on The Ski Boot in my most viewed post to date; THE SHOCKING TRUTH ABOUT POWER STRAPS (1.)

The Root of Misinformation

Unfortunately for skiing, the relevance and significance of the knowledge contained in The Shoe in Sport was overshadowed by the publication in 1971 of the book, the Biomechanical Examination of the Foot, Volume 1 by Drs. Merton Root, William Orien, John Weed and Robert Hughes. The book lists what the authors call their “Eight Biophysical Criteria for Normalcy”. These criteria, which have since been challenged and shown to be largely invalid,  were claimed to represent the “ideal physical relationship of the boney segments of the foot and leg for the production of maximum efficiency during static stance or locomotion”.

A key component of the biophysical criteria was that a bisection  of the lower third of the leg be perpendicular to the ground and the subtalar joint rest in neutral. Root described neutral as occuring when the subtalar joint was neither supinated or pronated.

In order to be considered normal, a foot had to meet all eight biophysical criteria. The effect of this criteria, which was arbitrary, was to render the majority of the feet of the world’s population abnormal and candidates for corrective interventions. Although Root never stated, implied or suggested it, his neutral sub-talar theory appears to have been misinterpretated in the ski industry to mean that the foot functions best in static ski stance when its joints are immobilized in neutral (sub talar).

In recent years, Root’s Sub-Talar Neutral Theory has come under increasing challenge with calls to discontinue its use (2.).

Conclusions
Taken as part of a wider body of evidence, the results of this study have profound implications for clinical foot health practice. We believe that the assessment protocol advocated by the Root model is no longer a suitable basis for professional practice. We recommend that clinicians stop using sub-talar neutral position during clinical assessments and stop assessing the non-weight bearing range of ankle dorsiflexion, first ray position and forefoot alignments and movement as a means of defining the associated foot deformities. The results question the relevance of the Root assessments in the prescription of foot orthoses.

The results of the wider body of evidence have the potential to have profound implications for skiing in terms of the application of Root’s Subtalar Neutral Theory as putting the foot in the most functional position for skiing by supporting and immobilizing it in neutral (subtalar).


  1. https://wp.me/p3vZhu-UB
  2. https://jfootankleres.biomedcentral.com/articles/10.1186/s13047-017-0189-2

THE IMPORTANCE OF STRONG HEALTHY FEET IN SKIING

My work with skiers spanning more than 4 decades, in conjunction with what I have learned over the past three years and papers I have recently read, has led me to the inescapable conclusion that the best equipment available, including ski boots that constrain the foot with minimal interference to foot function, can never overcome the limitations of unhealthy, weak feet.

In working with elite skiers at both the World Cup and recreational levels, it quickly became apparent to me back in the ’70s that these skiers consistently had stronger, tighter feet than lesser skiers. They also had feet whose compact, tight physical characteristics allowed them to attain a good level of function in most ski boots of the day right out the box.

The photos below are of the foot of a female racer who learned to ski at a young age in her mother’s ski boots when her feet were much smaller than her mothers’. The photos were taken when the racer was 20.

wedge-1

When she started racing at 5, she quickly became a phenomenom. She did not outgrow her mother’s boots until she was 11. So the critical period in the development of her feet took place under minimal constraint from her ski boots. Note the ‘natural’ (see footnote 1. below) wedge shape of her foot. There is some evidence of structural damage to her small toe. This could have occured after her she was put in tightly fit (constraining) ski boots at age 12 that were at least one size too small.

wedge-2

Here is the same foot with an outline of a typical boot liner overlaid in red.

liner-outline

Like most, until recently I reasonably assumed that the feet I have today were the feet I was born with; that good skiers were born with good  feet and there was nothing that could be done if one didn’t win the foot lottery at birth. I knew of nothing to indicate otherwise until I started to connect with the rapidly emerging barefoot/minimal shoe camp and the wealth of information on the foot damaging, often debillitating effects, of footwear, especially when one is subjected to foot damaging footwear at an early age. It was only then that I realized that the problems that prevented me from skiing as well as I thought I should didn’t start when I changed from low cut leather boots to the new higher, rigid, all plastic boots. My problems actually started when I was fit with my first pair of ‘orthopedically correct’, stiff-soled, supportive shoes when I was about two. The plastic ski boots only made the damage caused by these shoes, which persists even today, obvious.

An article in the August 9, 2010 edition of the UK newspaper, The Guardian, Why barefoot is best for children contains the following statement.

https://www.theguardian.com/lifeandstyle/2010/aug/09/barefoot-best-for-children

Tracey Byrne, podiatrist specialising in podopaediatrics, believes that wearing shoes at too young an age can hamper a child’s walking and cerebral development. “Toddlers keep their heads up more when they are walking barefoot,” she says. “The feedback they get from the ground means there is less need to look down, which is what puts them off balance and causes them to fall down.” Walking barefoot, she continues, develops the muscles and ligaments of the foot, increases the strength of the foot’s arch, improves proprioception (our awareness of where we are in relation to the space around us) and contributes to good posture.”

When I was fit with my first pair of shoes as an enfant, the big buzz phrase was ‘orthopedically correct’. This implied that orthopedic research had identified a signifcant problem, one that required intervention in the form of supportive shoes in order to ensure that an infants’ feet developed ‘properly’ and that the orthopedic community was behind this initiative. The cover story was that infants feet were weak and incapable of supporting the weight imposed on them in learning to walk. This could cause stress on bones that could lead to permanent deformation of the structures of the feet and legs. Orthopedically correct shoes with stiff soles and sidewalls that supported the foot would ensure proper and ‘normal’ (‘normal’, not ‘natural’ see footnote 1. below) development. This implied that parents who failed to put their infants into orthopedically correct shoes were guilty of child neglect.

Unfortunately for me, my mother had dated a guy in high school who opened a shoe store near our home. He was very much into orthopedically correct shoes. After he sold my mother on the idea she purchased every pair of shoes for me, all orthopedially correct, from his store right up until I was about 5 or 6 years old. The impact on my feet and my childhood was significant.

By the time I entered elementary school, my gait was so impaired that I could not walk in a straight line. Instead, I walked with a distinct, pronounced stagger that was so obvious that my school mates made fun of me. I was clumsy and unsteady on my feet. I fell a lot. My school mates started to refer to me as ‘the gimp’.  (see footnote 1. below)

As hard as I tried, I was never able to make any sports team I tried out for. By the time I reached junior high school, I had given up trying. The interesting paradox was that I could easily outpace all of my friends on a 2 wheeled pedal bicycle. I found out why when I had fitness testing  in 1988. I had a VO2 max of 66 which is phenomenal. So, it wasn’t a lack of stamina or athletic ability that was the issue. It was clearly the damage caused to my feet by the orthopedically correct shoes I was put in as a child.

The Guardian article, Why barefoot is best for children, notes that a study published in 2007 in the podiatry journal, The Foot, suggests that structural and functional changes can result from the foot having to conform to the shape and constriction of a shoe and that the younger the foot, the greater the potential for damage. Since baby feet are structurally different from adult feet, research shows that footwear can, indeed, obstruct proper foot development.

Tracey Byrne: “The human foot at birth is not a miniature version of an adult foot. In fact, it contains no bones at all and consists of a mass of cartilage, which, over a period of years, ossifies to become the 28 bones that exist in the adult human foot. This process is not complete until the late teens, so it is crucial that footwear – when worn – is well chosen.”

In the same article, Mike O’Neill, a consultant podiatrist and spokesperson for the Society of Chiropodists and Podiatrists, said that he believes that too many parents treat their children as fashion accessories and choose shoes on their attractiveness or coolness, rather than their ergonomics. Byrne agrees, but points out that it’s not just parents but manufacturers who have a responsibility. “People see particular shoe styles on sale in the shops – whether it’s a high heel for toddlers, a ‘Crawler’ (a shoe for babies not yet walking) or a cute Havaiana flip flop, with no more than an elastic band at the back … And they think ‘Well, if it’s on the shelf, it must be OK,'” she says.

“As more and more evidence comes to light regarding the importance of going barefoot and the potential dangers of bad footwear, the ‘barefoot model’ will have to become more widely adopted by shoe manufacturers,” says Byrne.

The Bottom Line

“……… the bottom line is the more we use our feet and toes, the stronger they will become. By wearing less of a shoe, we will use our toes to stabilize the foot against the ground and by activating these muscles more often, they become stronger. Simple concept, yet we’ve been missing it for over 40 years by focusing on building the perfect shoe. We already had the perfect shoe, our own foot. We just needed to wake it up and use it. By feeling the ground, our foot can tell the brain which muscles to activate and the foot responds by absorbing shock and working more naturally- the way it was intended to work.  (see footnote 2. below)

“We’ve come to regard the way we dwell permanently in shoes as normal and natural [but it is] anything but,” explained John Woodward, an Alexander Technique teacher who has allegedly been barefoot for 25 years.” ((see footnote 3. below)

All of the preceding applies to ski boots.

In my next post I will explain why going barefoot as much as possible will strengthen the feet but barefoot alone is unlikely to correct the damage done, especially if it was done when feet were developing.


  1. Why Shoes Make “Normal” Gait Impossible: How flaws in footwear affect this complex human function By William A. Rossi, D.P.M. – http://www.unshod.org/pfbc/pfrossi2.htm
  2. STUDY DEMONSTRATES VIBRAM FIVEFINGERS WILL STRENGTHEN THE FOOT. http://www.drnicksrunningblog.com/study-demonstrates-vibram-fivefingers-will-strengthen-the-foot/
  3. Why barefoot is best for children  – https://www.theguardian.com/lifeandstyle/2010/aug/09/barefoot-best-for-children

DETERMINING OPTIMAL BOOT SHAFT/BOOT BOARD RAMP ANGLE

A follower of skimoves posed the following;

“I’m trying to determine my optimal boot shaft angle and ramp angle given my physiology – i.e. what works best for me. I’ve done some of this work on my own by adjusting binding ramp angle (last season). What is interesting is the shaft angle of my newer Head vs. Lange boots”.


As discussed in recent posts, the importance of the cumulative effect of boot board ramp (zeppa) and binding ramp (delta) angles on stance is becoming increasingly recognized. Although binding ramp angle (delta) typically varies widely from one binding to another in recreational bindings, boot board ramp angle seems to be coming into line with functional reality in race boots. Reliable sources in Europe tell me that the boot boot board ramp angle in World Cup boots is in the order of 2.6 degrees. After I eliminated the arch profile in boot boards for a 23.5 Head race boot, I calculated the ramp angle at 2.35 degrees, a far cry from the 5 degrees claimed for the boot boards. I calculated the boot board ramp angle of an Atomic race boot of a local ski pro at a little over 2 degrees. I have also been told that shim kits are available for all race bindings that allow the delta angle to be zeroed.

The default barefoot ramp angle for humans is zero. It has been unequivocally established that anything more than a small amount of ‘drop’ (heel higher than forefoot) in footwear will have a detrimental effect on stance, balance and movement patterns. This especially true for balance on one foot, something that is fundamental to sound ski technique.

Elevating the heel relative to the forefoot will cause the muscles in the back of the lower leg to contract. Over time, these muscles will become chronically shortened. The key muscles affected are the calf muscles; the gastrocnemius and soleus. But the small muscles that stabilize the knee and pelvis are also adversely affected, not a good thing.

If I want to find the optimal boot shaft angle and compare the shaft angle of two or more boots, I start by making the boot boards perfectly flat with the transverse aspect horizontal with the base of the ski. I set the boot board ramp angles for both boots at 2.5 or 2.6 degrees. Since it can take a long time for the body to adapt to even small changes in ramp angle underfoot, the angle is not hypercritical.   I have settled on 2.5 to 2.6 degrees of total ramp (zeppa + delta) as an arbitrary starting point. Although there appears to be a positive effect of a small delta binding angle in SL and GS, I prefer to work with a zero delta angle initially since a positive or negative delta affects the shaft angle of a ski boot.

When moving from one boot model to a different model or to another boot brand, the first thing I do is remove the boot boards and calculate the ramp angles with the top surface monplanar. If the boot boards are not flat, I plane or grind them flat. If a new boot is to be be compared to a current boot with a boot board angle of 2.5 to 2.6 degrees, I modify the boot board of the new boot so it has the same angle as the current boot.

Next, I compare the shells and the angles of the spine at the back of the shaft of each boot. Even if the angles of the spines of the boot shells appear similar, there is no guarantee that what I call the static preload shank angle (more on this in a future post) will be the same.

A quick check of how the structure of the shell of the new boot is affecting the functional configuration of the foot and leg compared to the current boot, is to put the current boot on one foot then put the new boot shell with the liner from the current boot on the other foot. If a significant difference is perceived, the source is the new shell.

At this point, it may be apparent that there is a difference in the shank angles of the left and right legs when comparing the current boot to the new boot. But whether one boot is better than the other or even if one boot eanables the optimal static preload shank angle would not be known. I will explain how I identify this angle in my next post. For now, study this recent video of Lindsey Vonn starting off by skiing in what appears to be a strange ski stance. In fact, the exercise Vonn is doing is a familiar routine to me, one that I do before I start skiing – https://www.facebook.com/LindseyVonnUSA/videos/10154672700589728/

Why is Vonn skiing this way? What is she trying to do?

Also, check out this screen shot of Anna Fenninger. Note her compact, forward in the hips stance.

fenninger-1

Finally, watch this video in which Brandon Dyksterhouse compares Shiffrin and Fenninger – Shiffrin GS Analysis – https://youtu.be/phchHWwDhdY

What do Vonn and Fenninger have in common? Why?

 

BOOT BOARD (ZEPPA) RAMP ANGLE VS. BOOT SIZE

It is becoming clear, the angle the boot board (zeppa) establishes for the skier’s foot relative to the ground, is vitally important to the ability to balance and function on skis. Therefore, knowing boot board angle (ramp angle) and skier preferences should become part of every boot setup and purchase. Yet there appears to be a fundamental error in the understanding of ramp angle in boots. This is evident when someone states, for example: “The head Raptor has a ramp angle of 4.5 degrees”. The statement may only true if the angle is linked to the boot size.

There are production controls applied to boots just as controls and standards are applied to all other things mass produced. In boots, it means the first prototypes are designed to a specific size (generally Mondo 26). All other sizes are scaled up or down from it. Each Mondo size is a change of one centimeter. Zeppas are fixed in both rear foot and forefoot height in the prototype standard. Only the zeppa length changes as boot size changes.

It means; if the prototype size is twenty six, the zeppa of a twenty three is three centimeters shorter with the same toe and heel heights. Therefore, the ramp angle of the zeppa of a twenty three is steeper than the ramp angle of the zeppa of a twenty six. Since many women’s boots are scaled from the twenty-six Mondo standard, boot set-up problems can be more difficult to solve for women than for men. This is the reason women are more adversely affected by boot configuration than men. The graphic below compares the boot board (zeppa) ramp angles of larger and smaller boots to the standard Mondo 26 boot.

Zeppas Mondo 26

 

Bindings obviously confer the same effect, since with most models heel height is greater than toe height. As the heel and toe change distances from each other according to boot size, binding angle (delta) changes and its angle is additive with the boot ramp angle to determine gross equipment angle as shown in the graphic below. Binding delta has a double effect, since as delta increases boot cuff angle relative the ground also increases.

Zeppas Mondo 26 bindings

When talking about boot boad ramp, we should include the boot size or always use the ramp of the Mondo 26 as a known reference.


Lou Rosenfeld has an MSc. in Mechanical Engineering with Specialization in Biomechanics earned at the University of Calgary Human Performance Laboratory. His research was titled, “Are Foot Orthotic Caused Gait Changes Permanent”.

While at HPL, he assisted with research on the effects of binding position for Atomic, and later conducted research for Nordica that compared Campbell Balancer established binding position to the Nordica factory recommended binding position.

Lou is one of the invited boot-fitters on the EpicSki forum “Ask the Boot Guys” and has authored articles on boot fit, balance, alignment and binding position for Ski Canada, Ski Press, Super G, Calgary Herald, and Ski Racing, USA. He is a CSIA Level 2 instructor and CSCF Level 1 coach. He currently resides in Calgary where he owns and operates Lou’s Performance Centre. A selection of his articles may be found at www.Lous.ca.

RACE BOOT SETUP: BODY ALIGNMENT CHECK

Since this is the time of year when racers tend to either make changes to their boots or change to a new boot brand, I will describe the initial steps in the process (and it is a lengthy process) that I follow in setting up ski boots for a racer. Although the process is similar for any skier, it may be less structured and less intensive depending on the desired end result.

As a general rule, the closer a racer’s boots are to creating an optimal functional environment for the feet and legs (lower limbs), the more critical any changes become. Optimal is a moving target in that ski boots have such a significant effect on racer/skier function that the body is constantly making small changes in an effort to maximize performance. In my experience, that the farther a racer/skier’s boots are from optimal, the more unlikely that any changes, even in the wrong direction, will create a noticeable impact on performance. But when the boot/binding/skis system is close to optimal, even small changes can have a large impact. In this situation, changes in boot board ramp angle of a tenth of a degree or changes in the thickness of an insole of a mm are usually readily perceived by an elite racer/skier.

Where to Start? The body

The process starts with a quick visual assessment of the racer’s posture to see if any obvious issue such as significant duck feet (toed out) of one of both feet are present. The ideal Plumb Line Alignment of the major body segments and joints is shown in reference books such as Muscles Function and Testing, Third Edition by Kendell and McCreary. The most mechanically efficient alignment occurs when the gravity line of a plumb bob as viewed from the side falls through the back of the ear lobe and passes through the center of the shoulder joint, just behind the center of the hip joint and just in front of the centers of the knee and ankle joints.

If any structural issues are obvious, I recommend that the racer/skier have alignment and kinesologic assessments done by certified medical professionals. This is especially important if a skier or racer has been injured. Often, full function has not been completely restored.

I am not talking about the static alignment usually done in ski or boot fit shops. I am talking about an assessment process that evaluates and corrects the processes responsible for the maintenance of dynamic alignment, generally referred to as balance. It is superior balance that gives elite racers and skiers the edge over others.

One of the several resources in Whistler that I personally use is Dr. Andrea Bologna, DC, CACCP of the Village Centre Chiropractic & Massage Centre. Dr. Bologna wrote the following as an overview of the process that she uses to assess Body Alignment (Structural).

Body alignment (structural) assessment gives a skier a baseline to determine any deviations from “normal” in terms of positioning and alignment of the structure of the body.  Correcting misalignments will give a skier the edge on not only skiing or any other activity pursued by taking stress off of joints and muscles, improving posture and allowing the body to move freely with the correct biomechanics.

The following components make up the Body Alignment (Structural) Assessment

Step 1: A complete history is taken that includes past injuries, activities, etc.

Step 2: Body posture is assessed to determine how the body lives in space.

Assess main postural alterations and compensatory changes.

Anterior-Posterior Posture:

  • The pelvis may show a high ilium on one side and/or rotational component to the sacrum which may stem from changes in the spinal structure or in ankle or knee alignment and biomechanics.
  • One shoulder may be elevated and/or a rotational component observed to the rib cage.
  • Head tilt and/or a rotational component may be observed.

Lateral Posture:

  • An increase or decrease in the lumbar lordosis and/or thoracic kyphosis may be observed.
  • Knees may be hyper-extended.
  • One or both shoulders may be rolled forwarded.
  • Head forward position may be observed.

Step 3: Two computerized spinal scans are performed (thermal and EMG or electromyography) to determine which areas of the spine have nerve irritation or interference and which muscles are working harder or pulled tighter due to physical stress.

Step 4: A 3D digital foot scan is performed to determine changes in the arches of the feet, compensating posture affecting the knees and pelvis, and weight imbalance between the right and left sides of the body.

Step 5: A palpatory spinal assessment will determine spinal misalignments causing altered structure and resulting aberrant biomechanics.

The body evaluation process is key to determine what changes need to be made to correct the body structurally to allow for ideal biomechanics during ski training and racing.  The evaluation will determine the most specific way to adjust the spine and related joints for lasting results in the shortest time possible.

Dr. Andrea graduated from Parker University in Dallas Texas with a doctorate of chiropractic in 2005. She completed a 180 hour certification in Chiropractic Pediatrics from The Academy of Chiropractic Family Practice and the Council on Chiropractic Pediatrics. She is Webster Certified through the International Chiropractic Pediatric Association.

Dr. Andrea specializes in pediatrics and pregnancy, and sees a variety of world class athletes as well as weekend warriors. She moved back to BC to work together with her brother Dr. Michael Bologna after living in Texas for 10 years, resides in Whistler, and enjoys downhill and cross country biking.

In addition to body alignment, it is also important to assess foot function. There are many excellent resources that I will discuss in future posts.

In my next post, I will discuss where I start the process of racer boot setup.

 

 

 

THE BOOT BOARD FACTOR

While the Ottawa researchers did not explore this aspect, they correctly identified that equipment, including custom insoles, technical skills and ski technique might explain why the pressures recorded under the heel and the head of the first metatarsal of some instructors were much higher than the pressures seen in the same locations in other instructors.  The University of Ottawa studies are the only ones I am aware where the researchers considered the effect  of what is known in research as uncontrolled variables on their findings. Poor technique and interference with the function of the foot and leg caused by the ski boot can ensure that COP remains under the heel.

Although boot board ramp angle and shape have an undeniable impact on the function of the feet and lower limbs, as evidenced by the photographs below of a sampling of boot boards, there does not appear to be any continuity, let alone any standard for boot board ramp angle and the form of the surface that interfaces with the sole of the foot.

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IMG_0144

When the effect of  binding ramp angle, which appears to have even more variation than boot board ramp angle, is added to ramp angle equation to arrive at Net Ramp Angle, the possible combinations that make up Net Ramp Angles becomes unlimited and can range from as little as two to as much as ten degrees.

As if the lack of any apparent standard for boot board and binding ramp angles were not causing enough of an impact on skier/racer performance, there is a factor that appears to be compounding the issue by introducing a layer of inconsistency; boot base shell deformation under loads typical of recreational skiing.

I will discuss boot base shell  deformation in a future post. In my next post I will propose a starting point for a boot board standard.