Skier Balance posts

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 thnking 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

IS SHIFFRIN ON THE LEVEL?

By on the level, I am suggesting that Shiffrin may have a much lower zeppa-delta ramp angle than her competition.

Here are some screen shots from the March 18, 2018 Are Slalom where Shiffrin won by  1.58 seconds. She is on and off her edges in milliseconds as she just seems to pop from turn to turn – Total Domination From Shiffrin (1.)

Compare the angles of Shiffrin’s ankle, knee and hip in the photo below to those of her competition in the second and third photos below.

Notice how extended Shiffrin’s lower body is as she exits the rise line and enters the bottom of the turn in the photo below from a training session earlier in the year.

Extended in the Are Slalom.

Out of the start her knees and ankles are almost straight!

In my next post I will explain what I think is happening and why.


  1. https://youtu.be/gQu-LkyfsRQ?list=PLo6mlcgIm9mzWPBpeXnH2CpFOXrWhBiEB

RAMPING UP THE POWER OF YOUR STANCE

Note to the reader

The post that follows was originally published on March 1, 2016. At the time that I wrote it, I was trying to identify the optimal net (total) ramp angle or NRA using fixed angle ramps. But I found the process to be inconclusive for reasons I give in my recent posts on the dynamic ramp assessment device. I am reposting this older post because many of the concepts expressed are even more relevant in view of the results seen with the dynamic ramp assessment device and boot boards altered to the same ramp angle identified in dynamic testing.


RAMPING UP THE POWER OF YOUR STANCE

The foundation of a strong technique is a strong stance. But what makes a strong stance? The angle of the combined ramps of the binding and boot board or zeppa in relation to the base of the ski. If the net ramp angle weren’t important, binding and boot makers would make their products with no ramp. If ramp angle doesn’t make a difference, why bother? But not only does net ramp angle make a difference, it has a significant effect on stance.  Stance affects balance and muscle power, especially the ability of eccentric gastrocnemius-soleus complex muscle contraction to absorb shocks that would otherwise be transmitted up the leg to the knees and back. I discussed some of these issues in WHAT’S YOUR ANGLE? – : https://skimoves.me/2014/03/29/ski-boots-whats-your-angle/ ‎

If there were a problem, and there is, the ski industry is all over the place especially when in comes to binding ramp. There doesn’t appear to be any industry standards and especially any continuity between products. Worse, most skiers assume that their ski boots are putting them in the optimal stance. Without a reference they have no way of knowing. The Stance Ramp can give them that reference especially when it comes to how much ramp is enough, how much ramp is too much and how much ramp is too little.

Note Added March 19, 2018 – Having a kinesthetic sense of a stance based on tensegrity gives a skier a valuable tool that when used in a structured process can help them assess the effect of zeppa-delta ramp angle and the constraint imposed on their feet and legs by the structures of a ski boot.

In 1978, when I was building boots for female racers with small feet, I noticed that they were skiing like they were wearing high heel shoes. When I started checking their bindings and boot board ramps, I found out why. Some had 10 or 12 degrees or more of net ramp angle. After I started doing stance training with racers on a ramped board I discovered through empirical experiments that about 3 degrees of ramp angle seemed to give skiers the strongest stance.

Note Added March 19, 2018 – It now appears as if 3 degrees is the upper limit of the zone of stability. This explains why skiers started to ski better when the net ramp angle approached 3 degrees.

I didn’t really understand why until much later. Was the process scientific? No, not at all. Do studies of this critical issue need to be done? Absolutely. If I figured out that ramp angle was a critical issue almost 40 years ago, why is it that no studies appear to have done in the intervening years to determine the affects of ramp angle and identity the optimal angle?

With input from skiers in different parts of the world over the past two years, I have narrowed the ideal ramp angle down to about 2.7 degrees. This seems to be something of a standard in World Cup. Through experiments over the past few months, I have found that changes of 0.1 degrees can make a significant and easily perceivable difference. Optimal ramp angle isn’t just critical for World Cup racers, it is critical for all skiers. The easiest way to convince yourself of the importance of optimal ramp angle is for you to experience the effects of ramp angle through experimentation. How? With a Stance Ramp set to a base reference angle of 2.5 degrees.

The Stance Ramp lets skiers stand in their ski stance (barefoot is best) on a flat, level, surface then assume the same stance on the Stance Ramp, compare the kinaesthetic sense and judge whether they feel stronger of weaker. The angle of the Stance Ramp can be predictably increased or decreased by inserting shims at either end between the ramp and the surface it is supported on. When the ramp angle that makes the stance feel the strongest is arrived at, it can compared to the ramp angle of the ski boot board by having one foot on the Stance Ramp and the other in the ski boot.

The best part? The Stance Ramp is easy and inexpensive to make with readily available materials. I made mine out of some scraps of plywood I had lying around. Here’s what the Stance Ramp I made looks like. You stand with one foot on either side of the stiffener in the center with your heels at the high end (left end in the photo below).

IMG_6304

Here’s a top (plan) view. It is a good idea to check the surface the ramp will sit on to make sure it is very close to level.

IMG_6302

Here’s the underside of the Stance Ramp showing the element at the rear that gives the ramp its 2.5 degree angle. The stiffener in the center is important to ensure the ramp doesn’t flex under your weight.

IMG_6309

The sketch below is a basic plan for a Stance Ramp. The only critical details are the height or thickness of the element that lifts the rear aspect of the ramp to achieve and 2.5 degree angle (angle A) and the distance the lift element is placed from the front edge of the ramp. The stiffening element in the center of my ramp is 8 cm wide. The ramp has to be big enough to stand with the feet under the hips and long enough to accommodate the length of the feet.

Stance Ramp

An online right angle calculator such as the one at cleavebooks.co.uk can be used to calculate the spacing of the lift element from the low end (front edge) of the ramp based on its thickness.

SR calculate

Once the optimal ramp angle is arrived at, the Stance Ramp can be used in combination with the ski boot shell to confirm that the boot board is at the same angle.

IMG_6307

In my next post, I will discuss what I call the Resistive Shank Angle that is the base to build  a strong stance on.

WHY STANCE TRAINING IS ESSENTIAL

When readers click on my blog address at skimoves.me, analytics give me a hierarchy of the countries with the most views and the most popular posts in ascending order. This helps me identify which content resonates most strongly with viewers and which content draws a blank.

As I write this post, the top five countries are the US followed by Croatia, the United Kingdom, Slovakia and France.

The most viewed post today is THE SHOCKING TRUTH ABOUT POWER STRAPS; far and away the most popular post I have published to date. But the most important posts by far that I have ever written, A DEVICE TO DETERMINE OPTIMAL PERSONAL RAMP ANGLE and STANCE MUSCLE TENSIONING SEQUENCE EXERCISE barely sputtered in comparison. This strongly suggests that far from just some small gaps in the knowledge base skiing is founded on, massive craters exist.

Arguably the most important aspect of skiing is a strong stance. Any variance in the fore-aft angle of  the plane of support under the feet and the plane of the base of the ski has significant impact on stance. Yet these subjects are barely blips on the Doppler Radar of the ski industry.

Since I started the dynamic ramp angle assessment project a few weeks ago I have found that when asked to do so, it is rare for a skier of any ability to be able to assume a strong ski stance in an off the ski hill environment. Even when a skier  skis with a relatively strong stance, they seem to lack a sense of what a strong stance feels like. Because of this, they lack the ability to consciously replicate a strong stance. If asked to do so, they would be unable to coach a skier in the sequence of events that I described in my last post

In the dynamic ramp angle assessment project, I  have also observed that skiers with with a boot/binding ramp angle greater than 2.8 degrees appear to have become accustomed to the associated unstable, dysfunctional feeling and identify with it as ‘normal’. Before I can test them, I have to spend time coaching them into the correct stance because it feels unnatural to them.

When I go back and forth between a strong functional stance on a flat, hard level surface to a stance on the dynamic ramp angle device set to an angle of 4 degrees, I can get close to the same angles of ankle, knee and hip. But when I do, I feel strong tension, stiffness and even pain in my mid to lower back which is  common in some skiers and even racers.

Based on results to date with the dynamic ramp angle device, it appears as if strong skiers ski best with ramp angles close to zero. But depending on their sense of balance and athletic ability, they may have a wide range in which they sense little difference on the effect of ramp angle until they approach the upper limit of stability. While they may be able to ski well with a ramp angle close to the maximum limit of stability, ramp angles much above 1.2 to 1.5 degrees may not offer any benefits. This can only be tested on skis where balance is tested by dynamic forces which cannot be replicated in a static setting.

Issues affecting skier stance were discussed in detail in my post, THE SHOCKING TRUTH ABOUT POWER STRAPS. Here are the excerpts I posted from the chapter on The Ski Boot in the book, The Shoe in Sport (1989), published in German in 1987 as Der Schuh Im Sport– ISNB 0-8151-7814-X

“If flexion resistance stays the same over the entire range of flexion of the ski boot, the resulting flexion on the tibia will be decreased. With respect to the safety of the knee, however, this is a very poor solution. The increasing stiffness of the flexion joint of the boot decreases the ability of the ankle to compensate for the load and places the entire load on the knee”. – Biomechanical Considerations of the Ski Boot (Alpine) – Dr. E. Stussi,  Member of GOTS – Chief of Biomechanical Laboratory ETH, Zurich, Switzerland

“The shaft of the boot should provide the leg with good support, but not with great resistance for about two thirds of the possible arc, i.e., (14 degrees) 20 to 22 degrees. Up to that point, the normal, physiologic function of the ankle should not be impeded”.

“Previous misconceptions concerning its role in absorbing energy must be replaced by the realization that shaft pressure generates impulses affecting the motion patterns of the upper body, which in turn profoundly affect acceleration and balance.

“When the lateral stability of the shaft (the leg) is properly maintained, the forces acting in the sagittal direction should not be merely passive but should be the result of active muscle participation and tonic muscular tension. If muscular function is inhibited in the ankle area, greater loads will be placed on the knee”. – Kinematics of the Foot in the Ski Boot – Professor  Dr. M. Pfeiffer – Institute for the Athletic Science, University of Salzburg, Salzburg, Austria

It has been over 40 years since international authorities on sports science and safety raised red flags concerning the adverse effects of ski boots design and construction on skier stance, balance and the potential to cause or contribute to injury. It is time that their concerns were taken seriously and acted on. Research on stance and the effect of such things as zeppa and delta ramp angles is urgently needed.

 

FIFTH GENERATION STANCE RAMP ASSESSMENT DEVICE

Since my first version of the stance ramp assessment device I have made a number of significant improvements. The series of photos below are of the fifth generation device.

The bottom plate or base of the device is approximately 18 inches (46 cm) wide by 16 inches (41 cm) deep (front to back). I intend to make the next version about 22 inches (56 cm) wide by 18 inches (46 cm) deep. Size is not critical so long as the top plate is deep and wide enough for the feet being tested.

Stiffness of the plates is critical. Three quarter inch thick (2 cm) plywood or medium density fiberboard (MDF) are suitable materials. I added 1.5 inch x 1.5 inch wood reinforcing ribs on the sides, middle and rear of the top plate.

The photo below shows the heel end of the device. Two 1/4 inch drive ratchets turn bolts threaded into T-nuts in the top plate that raise the heel end up.

The photo below shows the top plate hinged to the bottom plate with 4 robust hinges.

Four telescoping hard nylon feet are set into the bottom plate to enable the device to be leveled and made stable on the supporting surface. It is important that the device not tilt or rock during testing.

The photo below shows the details of the interface between the top plate on the left and the bottom plate on the right.IMG_3409

I used gasket material purchased from an auto supply to shim the forefoot of my boot boards to decrease the ramp angle so as to obtain the 1.2 degree ramp angle I tested best at.Shim pack

The package contains 4 sheets of gasket material that includes 3 mm and 1.5 mm sheet cork and 2 other materials.Gasket

I cut forefoot shims from the 3 mm cork sheet as shown to the right of the boot board in the photo below.BB w shims

I adhered the shims to the boot board with heavy duty 2-sided tape and feathered the edges with a belt sander.shims installed

I corrected the ramp of my boot boards in 3 stages. Once my optimal ramp angle is confirmed, I will pour a boot board into the base of my ski boot shells in place of the existing boot boards using a material such as Smooth-Cast 385 Mineral Filled Casting Resin. More on this in a future post.

Ramp Angle Appears to User Specific

It is important to stress that although there appears to be a trend to optimal boot board ramp angles for elite skiers in the range 1.5 degrees or less, there is no basis to assume a  ramp angle that is optimal for one skier will be optimal for another skier. Recreational skiers are testing best between 2.0 and 2.5 degrees.

It is also not known at this point whether the initial optimal ramp angle identified with the device will change over time. Based on the impressive results seen so far in the limited number of skiers and racers who were tested and ramp angles adjusted there is no basis to assume that ramp angle is not a critical factor affecting skier balance and ski and edge control. Studies on this issue are urgently needed and long overdue.

It is important that testing for optimal ramp angle be preceded by kinesthetic stance training. This will be the subject of my next post.

A DEVICE TO DETERMINE OPTIMAL PERSONAL RAMP ANGLE

This post contains the most important information I have ever written on skiing. It concerns the most important discovery I have made since I began to cast a critical eye on the positions of the various experts about 45 years ago; a method to determine the optimal personal ramp angle of a skier/racer.

By 1978, subjective experiments had taught me that a total ramp angle between the sole of the foot and the base of a ski of more than 3 degrees could have significant adverse effects on skier stability, balance and the ability to control the direction and especially the edge angle, of a ski. Wherever possible, I tried to limit total ramp angle (boot boards + bindings) to below or close to 3 degrees. But ski boot and binding construction often limited my ability to reach this objective. It was limitations in the construction of my current Head World Cup boot that presented challenges in getting the boot board ramp angle below 3 degrees. Through a concerted effort I had managed to reduce ramp angle to 3.3 degrees (bindings are zero) with a noticeable improvement in balance, ski and edge control. But the results of my recent NABOSO insole test suggested that the boot board ramp angle needed to be a lot lower.

The Dynamic Ski Stance Theory

A standard test of the human balance system is to subject a subject to dynamic changes in the platform under their feet. Over the past few years, I made numerous attempts to find the optimal ramp angle for skiing. One method involved assuming my strongest stance on a hard, flat level surface then stepping onto a plate shimmed to a fixed angle then repeating the process with the plate shimmed to a different angle. The results were inconclusive. Every time I went back to the hard, flat level starting surface my balance system seemed to reset. I had to get the angle of the tilted plate well over 3 degrees before I began to sense obvious instability. This led to my positing of a theory that the angle of a plate that a skier is standing on needs to be changed as the skier goes through a stance protocol designed to test stability and what I call a rooted or grounded connection where the skier feels as if their feet are literally rooted in the snow.

Research is Urgently Needed

Before I go any further I want to stress that I believe that an idea, no matter how compelling, is nothing more than a theory until it has been thoroughly tested and has withstood rigorous scrutiny. Even then, no theory should be immune to challenges. Research on this subject is urgently needed and long overdue. With this in mind, I designed the dynamic stance assessment device so it can be easily made with reasonable skills and readily available, inexpensive materials. I have recently completed a 4th generation prototype to serve this end. But a much more sophisticated device can and should be made and used by academic researchers. A servo motor driven ramp with a data acquisition package is the preferred option.

Stance Training is Essential

In order to obtain accurate results with the dynamic stance assessment ramp it is essential that the subject being tested undergo kinesthetic stance training and follow a protocol during testing that is designed to help the subject assess the effect of changes in ramp angle. It is disturbing that few of the skiers tested so far have a kinesthetic sense of the elements of a strong stance. Most have never sensed a strong stance. Worse, no ski pro or coach has ever discussed this crucial aspect of skiing with them. It appears as if it is simply assumed that a skier will automatically find their optimal stance. I can unequivocally state that this is not the case.

Dynamic Stance Ramp Test Results

  • The majority of skiers tested so far were most stable at ramp angles between 2.0 and 2.5 degrees.
  • A number of skiers, myself included, were most stable at close to or under 1.2 degrees.
  • One skier was most stable at 1.6 degrees.
  • One skier appeared to be relatively insensitive to ramp angle until it was above 2.8 degrees.
  • After training, most skiers were sensitive to changes of 0.1 degrees.
  • No skier tested so far was stable over 2.8 degrees.
  • Adding NABOSO insoles further reduced the ramp angle.

I tested most stable at 1.2 degrees; 2.1 degrees less than my existing boot board ramp angle. In order to reduce the boot board ramp angle to 1.2 degrees, I had to raise the toe end of my boot board 9 mm and lower the heel 2 mm for a total reduction of 11 mm.

First On Snow Impressions

Walking in my ski boots with the corrected boot board ramp angle immediately felt different. But the huge impact didn’t come until I started moving over the surface of the snow on my skis. Then the whole world seemed to change. I had a huge deja-vu moment; one that took me back to the solid, stable feeling I had under my feet in my first low-cut leather plastic soled ski boots. It was then that I realized that it was the jacked up heels of my first all plastic, rigid shell ski boots 45 years ago that had destroyed my balance and confidence on skis. This is a big miss for the ski industry, one that should have been caught by those who promote themselves as the experts in skiing, but wasn’t. This miss has huge implications for skiers at every level and ability all the way up to the World Cup. A skier, but especially a racer with a sub-optimal ramp angle will revert to an unstable weight on the heels, back seat Defensive Stance in which the skier is incapable of recruiting the enormous power of the glutes and optimal sensorimotor processes.

First generation device in action. Ratchet socket wrenches raise the ramp by turning bolts set into T-Nuts on each end.


Digital SmartTool electronic level accurate to 2 decimal places


Fourth Generation Stance Ramp assessment prototype. Two x two wood stiffening elements added to the platform.

The skiing of those whose ramp angle has been optimized is elevated to a whole new level provoking immediate comments like the difference is ‘night and day‘. After my transformation, I now believe that until ramp angle is optimized, everything else is irrelevant and that no amount of footbeds, orthotics, cants, alignment or custom fitting can overcome the adverse affect of sub-optimal ramp.

NABOSO: FIRST SKI TEST RESULTS

I finally got a chance to test Dr. Emily Splichal’s surface science small nerve stimulating NABOSO insoles (1.)

Naboso (meaning “barefoot” in Czech) is the first-ever small nerve proprioceptive material commercially available in the health and fitness industry. The skin on the bottom of the foot contains thousands of (small nerve) proprioceptors, which are sensitive to different stimuli including texture, vibration, skin stretch, deep …

As I typically do, I used a one on one test protocol with a NABOSO 1.5 insole in my left ski boot and my normal insole in my right boot. The results were nothing short of amazing. There was almost no difference in the feeling under the sole of my left (NABOSO) foot compared to the sole of my right (normal insole) foot. The NABOSO Effect (as I call it) in my left ski boot was nothing like the effect I experience in similar tests in my Xero Prios or Lems Primal 2 minimal shoes. You’re probably wondering why I was amazed if NABOSO was no better than my normal insoles. The fact that I felt little difference told me that something was seriously wrong with my ski boots.

The first thing I suspected was that there was too much ramp angle (aka zeppa) in the boot boards in my Head 335 World Cup boots. I can’t recall what the factory ramp angle. But I lowered the heel a lot and the reduced ramp angle seemed to work well compared to the original ramp angle. As a reference, the boot board zeppa angle in the Head RD boot is 4.0 according to Head literature. The zeppa in recreational ski boots can be as much as 7 degrees. Since 1978, I have known that too much boot board ramp angle can cause significant balance and ski control issues for skiers. But I had no way of accurately determining what the optimal zeppa angle should be. What appears to work well for one skier does not necessarily work for another skier. Zeppa is a crap shoot, a good guess, a lottery. A few skiers win the zeppa lottery. But most skiers lose. I decided that I had to find an accurate way to determine the optimal personal zeppa angle for skiers and especially racers.

Necessity is the mother of invention.

I had a need to know situation. In my next post I will describe the Dynamic Ramp Angle assessment  device that I designed and fabricated and the incredible results that happen when zeppa angle is in the optimal range and the NABOSO Effect kicks in. Prepare to be shocked by the results. I was. I am still in shock. If the results hold up, optimal boot board ramp angle will be a big miss for the ski industry.


  1. http://nabosotechnology.com