Ramp Angle posts

THE SHOCKING TRUTH ABOUT SKI BOOTS

In this post, I will expand on the content of The Shocking Truth About Power Straps (1.) which was by far the most popular post since I started this blog in 2013.

While the truth about what power straps can potentially do if improperly adjusted is shocking, the lack of support in principles of applied science for the basic premise that I describe as indiscriminate envelopment as the approach to achieving a fit of a ski boot with the foot and leg of the user with the objective of substantially immobilizing it’s joints with unknown consequences, is even more shocking. Little or no consideration appears to be given to the effects of indiscriminate envelopment on the balance and motor control systems of the skier.

What is done to the foot and (lower) leg can affect the entire body. In his post, Foot biomechanics is dead. Discuss (2.), Professor Chris Nester states:

The foot is not a compilation of interconnected mechanical components that respond precisely to the laws of mechanics. It is a complex matrix of at least 11 biological tissues (i.e. skin, fat, muscle, tendon, joint capsule, ligament, bone, cartilage, fascia, nerves, blood vessels….) that responds to external loads through the symbiotic relationship between the motor control system and tissue properties.

Professor Nester goes on to state:

I believe the integration of our current foot biomechanics knowledge with insights from motor control, neurophysiology and related domains (e.g. tissue biology) will drive advances in foot function more than pursuing a pure mechanics paradigm.

Professor Nester proposes that the term biomechanics be replaced with the term Neurobiomechanics. I concur.

How Does the Ski Boot Affect the Human Performance of the Skier?

The short answer is that when the structures of a ski boot indiscriminately envelop the structures of a foot and a portion of the leg (aka the Perfect Fit or the Holy Grail), no one knows. While it is essential that a ski boot create a secure connection of the foot of a skier with the ski, it should not achieve this connection at the expense of natural neuromuscular function, especially balance.

In 1980, when I was about to prepare a new pair of Lange race boots for Steve Podborski, I asked myself whether it was possible to obtain a secure connection of the foot with the ski without compromising natural neuromuscular function or, even better, was it possible to enhance natural neuromuscular function?

I took a significant step towards answering this question in 1980 when I designed and fabricated a device I called a Dorthotic. The Dorthotic supports the upper or dorsal aspect of the foot as opposed to supporting the plantar aspect (i.e. the arch). My theory that loading the top of the foot or dorsum with a force perpendicular to the transverse or medial-lateral plantar plane of the foot has positive benefits for motor control and balance has begun to be recognized. The Dorthotic enabled Steve Podborski to compete and win on the World Cup Downhill circuit mere months after reconstructive ACL surgery and to eventually win the World Cup Downhill title, a feat no non-European has repeated. US and international patents for the dorsal device were awarded to me (David MacPhail) in 1983.

The success of the Dorthotic gave me a start towards answering the question of whether a secure connection of the foot with a ski was possible without compromising natural neuromuscular function. But I knew that I needed to learn a lot more. I realized that finding the answers I was seeking and especially unraveling the secret that enables the world’s best skiers to stand and balance on their outside ski, would require a multi-disciplinary approach.

The Missing Factor in Skiing: A Multi-Disciplinary Approach

A significant influence that served as the impetus for the design of the Birdcage research vehicle and the on-snow studies, was the work of Dr. Benno Nigg. In 1981, Dr. Nigg accepted an invitation to move from ETH Zurich, where he was the director of the biomechanics laboratory, to the University of Calgary, where he founded and developed the Human Performance Laboratory (HPL), a multi-disciplinary Research Center that concentrated on the study of the human body and its locomotion.

The publication of the Shoe In Sport in English in 1988 served as a seque to introduce me to Nigg’s research at HPL. Studies done at HPL found that any interference with the function of the human foot, even a thin sock, extracts a price in terms of the adaptive process the human body has to undergo to deal with what is really an externally imposed disability.

The Effect of Footwear on the Neuromusculoskeletal System

There is an excellent discussion in a recent post on the Correct Toes blog (3.) on the impact of a narrow toe box, toe spring and elevated heel of traditional footwear on the human body. Elevating the heel in relation to the forefoot will predictably cause a realigment of the ankle-knee-pelvis joint system with a corresponding adjustment in the tension of the associated muscles with a global effect on the Neuromuscularskeletal System. This has been known for decades. Elevating the heel in relation to the forefoot, will cause the ankle joint to plantarflex (reduce dorsiflexion) in relation to the support surface under the foot in order to maintain COM within the limits of the base of support.

Ramp Angle Rules

Due to the unstructured nature of the indiscriminate envelopment characteristic of the fit of the majority of conventional ski boots, it is extremely difficult, if not impossible, to determine the effect of constraint of this nature on the Neuromusculoskeletal System. So I’ll focus on the one aspect of the ski boot that has consistent and profound implications on skier human performance, especially motor control and balance; boot board ramp angle or zeppa. Binding ramp angle or delta compounds any effect of zeppa. For the sake of simplicity we’ll assume zero delta.

Contrary to the widely help perception, raising the heel of a skier in a ski boot does not cause CoM to move forward. In fact, it usually has the exact opposite effect. It puts a skier in the back seat with the weight on their heels. Worse, it can disrupt the competence of the biokinetic chain that dynamically stabilizes and protects the joints of the lower limbs. Excessive heel elevation can render a skier static and cause the balance system to resort to using the back of the shaft as a security blanket.

As of this writing, I am unaware of any standard within the ski industry for zeppa. It appears to be all over the map with some boots having as much as 6.5 or more degrees. The default zeppa for the human foot on a hard, flat level surface, is zero.

Through subjective experiments in 1978, I arbitrarily determined that zeppas in excess 3° had a detrimental affect on skier balance. In 1991, zeppas of 2.3° and 2.5° were chosen for the large (US 8-12) and small (US 4-8) Birdcages based on an analysis of the effect of ramp angle on COM and neuromuscular activity. This range appears to work for a majority of recreational skiers. But recent tests with a dynamic ramp angle assessment device that I designed and fabricated is finding the stance of elite skiers optimizes at much lower zeppa angles, with some skiers below 1.5°. Interestingly, when NABOSO insoles are introduced for the assessment, zeppas decrease even further. With minimal training, most skiers are sensitive to dynamic changes in zeppa of 0.1 degrees.

Implications for the future of skiing

A tectonic shift is underway on a number of fronts (see A Revolution) that is challenging the mechanical and static premises that form the underpinnings of the key positions in ski teaching and the design of equipment such as ski boots and the fit process. In my next post I will post recent material by Dr. Emily Splichal, functional podiatrist and inventor the revolutionary NABOSO small proprioceptive stimulating insole.


  1. https://wp.me/p3vZhu-UB
  2. https://talkingfeet.online/2018/01/18/question-3-foot-biomechanics-is-dead-discuss/
  3. https://www.correcttoes.com/foot-help/footwears-impact-musculoskeletal-system/

MORE ON ZEPPA (BOOT BOARD) RAMP ANGLE

Slowly, but definitely, the ski community are learning the positive boot board (zeppa) ramp in many boots is excessive and not beneficial to many of us. Excessive seems to be anything over approximately 3.0 degrees. The lowest ramp I have measured to date was 2.4 degrees in the latest Dalbello DRS boot in a Mondo 27. A size 23 is still over three degrees.

I believe most manufacturers have too much ramp in their boots. As explained in a recent post, the problem is worse for smaller boots, since as boots shorten, ramp increases. Still, even if boot ramp is correct, we should wonder if binding designers think boot designers need some design help, since nearly all bindings have positive ramp (delta) of at least a few degrees for Mondo 27 boots.

Like boot zeppas, as binding toe and heel are mounted closer together, delta increases and is additive with boot ramp. Further, there are additional changes to boot angle since binding delta tilts the entire boot, It also alters effective forward lean.

I believe when we demo skis, a portion and perhaps a substantial portion, of the differences we feel between skis, may be accounted for by the differences between ski binding ramp angles. At the very least, binding angles can corrupt on-snow testing of skis and/or boots. If you are working to get your boot setup perfectly adjusted to your preferences, why allow binding ramp variables to alter an optimal configuration?

In my opinion, the best solution is a 0 degree binding delta. If this is not achievable, at least set all skis bindings to the same delta. This may be easily, achievable. Most manufacturers make shim kits for at least some of their bindings. Shims appear to be available for most bindings used on race skis that allow incremental changes to 0 degrees delta. However, not all shops know of the existence of these shims since  kits are usually in the race catalogue, not the recreational product catalogue.

If alterations to either binding heel or toe height are made, an equal change must be made to screw length or there will definitely be an unsafe situation. Binding holes are between 8.5 and 9.0mm deep. Be certain screw threads do not extend more than that amount from the bottom of the binding.

One last thing to remember is that moving binding position forward or backward on the ski could subtly alter binding delta since the top surface of skis are crowned. Moving the bindings to a new position on the crown will affect the height of the heel and toe. If bindings are moved after setting binding delta, it should be checked again.

I always prefer to direct measure rather than use a calliper and calculate zeppa or delta. The photos below show a device I had fabricated that allows the angle of a zeppa to be measured between the two primary load points under the heel and the head of the first metatarsa (aka ball of the foot). The distance between the rods can be adjusted to these two points on a zeppa or to the 2 points of contact of a boot sole on the heel and toe pieces of a binding.

img_0739

The SmartTool digital level shown in the photo below accurately reads to one decimal place.

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The SmartLevel is too long to sit properly on a zeppa. The two rods of the frame that supports the level lets me avoid toe kick or any other shapes that can distort ramp angle.  I just measure the angle directly between the two points of support.


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 PressSuper 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.

 

A FOLLOWER OF THE SKIER’S MANIFESTO COMMENTS ON BOOT BOARD/BINDING RAMP ANGLE

The universal boot truisms that David puts forth in his blog is a ‘blueprint’, ‘computer program’, what ever you want to call it which is applied on an INDIVIDUAL basis. Each individual is measured with the system and then the results are applied to the boot. Unlike ‘one boot fits all skiers’ which is the current system the industry provides. I can’t believe that anyone would buy a boot based on a ski magazine test but that probably is hardly worse than the info one gets in the ski shop which gave me nerve damage in my feet (gratefully healed now since I gave up on ‘race fit’). David talks about using flat shims of varying thicknesses to fine tune ramp angle just like canting shims or duct tape are used for lateral experimentation; 2.5-6 is his starting point while I would start with zero but with current ski bindings only millimeters of fine tuning can be done when some individuals need centimeters from the current setups. Obviously if one changes the ramp angle the shank angle may have to be adjusted also which is why skiing is believing, David gives a perfect example in his reply on what lower ramp angle did for his skiing. Also the extremely high starting point on ramp angle makes it impossible for many skiers to loosen their cuff for normal forward flex because they need to be clamped tight to prevent falling one their noses; that’s where I got fooled for a couple of decades.

Having built an adjustable plate for ramp/delta in the early 2000s I can tell you one thing for sure; the skier knows instantly if things are better or worse. That by no means indicates an optimum net ramp because there are so many other aspects of the boot that are factors such as toe crunch (race fit) and ankle flex restricted to virtually zero. I started from the wrong end with ramp/delta whereas David starts in the boot first which is what I would do but took me about a decade to loosen my boot cuff significantly enough to make a difference; that due to a hip joint that was killing me from skiing. 2 months after loosening the boot cuff and removing the power strap which is only good for carrying the boots (my opinion), I was introduced to The Skier’s Manifesto and learned from that how to create an ankle glide path, free the toes, free the arches, etc. What amazes me is 2 things; first that when I first decided to build the BalancEnhancer as I call it (due to a friend’s prodding), that it actually worked , and second, how hard it is to even get skiers to try something different and the number that do try it and then don’t even try to modify their own equipment to their needs based on what had made there skiing better!!

  • Michael Pupko

MORGAN FROM FRANCE FINDS HIS RAMP ANGLE

When Morgan Petitniot from France first contacted me on September 2, 2014 (CASE STUDY: MORGAN FROM FRANCE – HIS STORY (https://skimoves.me/2015/11/30/case-study-morga…france-his-story/), I had not started to look critically at boot board ramp angle and Net Ramp Angle.

When I posted SKI BOOTS – WHAT’S YOUR ANGLE? and CALCULATING RAMP ANGLE, two years ago, I knew that ramp angle could affect the function and especially the balance of a skier. But I had no idea how critical ramp angle is. Through subjective experiments back in the late’ 70s, I had identified that a ramp angle in the range of about 3 degrees made it easier to ski. But I had not made any attempt to narrow down the range or pursue the issue further. Nor did I understand back then exactly how and why ramp angle affected a skier.

After Morgan sent me the video he made in which he documented his experiments with different boots and skis, (MORGANS’ EXPERIMENTS WITH BOOT SETUP: 2013 TO APRIL 2015 https://skimoves.me/2015/12/09/morgans-experime…13-to-april-2015/), the range of effects on his skiing that he experienced from different boots and skis far exceeded what I had expected. The problem was that there was no reference against which to compare the different components against and little or no structure to Morgan’s process that would have allowed him to control variables and isolate and identify the effect of each change.

Morgan started to make progress with his skiing after he discovered The Skier’s Manifesto and began applying my principles. While he got closer to skiing at the level that he wanted to reach, it became clear to me that something was still holding him back. It was about this time that the interactions I was having with those such as Michael was helping me to gain a better appreciation and understanding of the critical nature of boot board ramp and Net Ramp Angle.

After reviewing the video clip below of Morgan skiing on January 17 of 2016 I asked him to check the ramp angles of his boots and skis. The dated comments that follow are from our email exchanges subsequent to January 17.

Morgan has improved a lot since we started working together. To the untrained eye, he looks like he is skiing quite well. But there are subtle indications that he is not able to Get Over It (get CoM over the ball of his outside foot). Morgan senses and confirms what I am seeing.


Jan 18

Morgan: Ok David, on my Fisher ski boot I am at 3.6 degree net ramp angle. I had to screw à 5 mm plastic matérial under the toe pièce of my ski boot you see it on the attaches photo\

Feb 11

Me: The biggest change for most skiers is to maintain a compact stance throughout the turn. The knee is the joint whose angle changes the most. The ankle stays fixed in the resistive angle while the knee flexes on the inside leg and extends on the outside leg to move COM over the ball of the foot. Rotating the outside leg into the body and using the inside leg to steady the pelvis enables COM to be aligned and maintained over the ball of the outside foot.

I generally do not encourage laces on liners because they can obstruct the glide path of the ankle and pollute the mechanoreceptors in the ankle that are key to balance. The liner you are using appears to be very soft. So it is unlikely it is causing significant issues. In my experience, liners can cause more problems than boot shells.

March 6

Me: In the past few months I have learned a great deal about the importance of ramp angle. It seems as by chance I chose race bindings that have zero ramp angle  for my skis when I got them 2 years ago. I have since learned that very few bindings have zero ramp. I have checked many bindings last week and found that no consistency in ramp angle. They all seem to be different. Worse, it changes with boot length. This is a big problem. A few weeks ago, I reduced the ramp angle of the boot boards in my boots to 2.6 degrees from 3.0 degrees and immediately sensed a huge improvement in balance, ski control and the ability to absorb shocks.

A week ago I was asked by a relatively new skier to help her with her boots because she is taking her CSIA Level II course and experiencing difficulty trying to do the exercises. I checked her boots first. They were far too small, too tight and far too narrow in the forefoot. She has a small but wide forefoot. When I checked her bindings they had 1.9 degrees of ramp. Her total or net ramp is almost 6 degrees!

I am about to post on tests that can and should be done with the Stance Ramp. The first test is to double the 2.5 degrees of the ramp to 5.0 degrees. You will immediately feel unstable on the ramp. This is the minimal ramp that most recreational skiers have between their boots and bindings. Many skiers have far more.  The problem is that most recreational bindings available today cannot be shimmed. Please check your bindings. If they have anymore than 0.2 degrees or ramp it is difficult to adjust for this in the boot board. If your bindings have ramp, I suggest you try and borrow or rent a ski similar to yours with zero ramp bindings and do a comparison test. Also, please check your boot boards and, if necessary, adjust the ramp to about 2.6 degrees. You can do tests  by placing thin shims of polyethylene under the heel or fore foot between runs to fine tune the ramp.

Please let me know what you find.

The best way is to drop the heel by grinding or planing the boot board down. I use a very sharp block plane to do this.

Try and build a Stance Ramp as soon as possible. I will give you exercises that are very telling in terms of what works best. You can easily sense this. Make sure the material you use is very stiff. Reinforce it, if necessary. You can easily bend the Stance Ramp platform it with pressure on the balls of the feet unless it is very stiff.

Morgan: I answer you quickly. According to your advices about ramp angle on december 2015, I have bought my skis “ATOMIC REDSTER SL” because of the binding ramp angle = 0°

Actually my boot board ramp angle (in the Fischers) is 3.8 !!!

I will made the test with trying to lift the forefoot (i don’t know if i have sufficient space to lift up my foot about 5 mm)

I am testing 2 pair of boot (head raptor 130 RS with 2.5 boot board ramp angle AND Fischer RC4 withe 3.6 boot board ramp angle) Now the only thing I can tell you : After 2 weeks I feel better in Fischer (edging, shank angle, more balance) but my back suffer. In Head boot (edging more difficult, shank angle not sufficient, balance –) but my back is better. Perhaps there is something to explore unless you have already understand what is happen 😉

March 7

Skype meeting to discuss next steps

March 17 – A Happy Ending

Morgan: I have the pleasure to say to you that. My back don’t hurt me anymore 🙂 🙂 Total ramp angle 2.8 (ski binding 0, boot board ramp angle 2.8)

More power, more balance, more reaction of skis. Gliding with the skis straight away, more relax and stable position and the feeling of the center position.

Great !!!

 

 

DR. BOB’S METHOD FOR MEASURING RAMP ANGLE

Introducing Robert Colborne, Ph.D

Dr. Bob, as we called him, was a consultant for the MACPOD ski boot project that conducted on-snow research with the Birdcage in 1991. His area of expertise is the human lower limbs and the quantification of moments of force or torques across the joints.

Dr. Bob’s method of measuring Net Ramp Angle offers some advantages over the method of calculating the individual angle of each component and then summing the angles to arrive at Net Ramp Angle. The drawback to Dr. Bob’s method is that it may not accurately capture the effect of toe spring, dual plane boot boards and heel lifts. I will describe the various aspects of ramp in my future post, THE MANY FACES OF BOOT/BINDING RAMP.


Dr. Bob on Calculating Net Ramp Angle

I had a little play with my skis/boots on the weekend. I built a ‘precision’ square (90 degrees) from a couple of pieces of wood and placed it in my Lange boot, mounted on the ski with the bottom arm of the square sitting on the bottom of the base assembly (boot board plus insole and heel lift).

In the photo below, the ski is decambered by the weight of the boot so the base is resting flat on the table. The slight curve created by the thickness of the ski that tapers towards the end that Michael mentioned can be seen. Moving the bindings forward as a unit lowers the toe boot interface and raises the heel boot interface. This increases binding ramp angle. Moving the bindings rearward as a unit has rhe opposite effect.

The angle of the vertical leg of the square can be measured with a precision inclinometer and subtracted from 90 degrees to arrive at NRA.

Skiboot

My Marker bindings are level heel/toe, so no ramp angle to account for there.  I had some problems with the shell of the boot coming in laterally below the hinge and rubbing on my lateral malleolus, so to get my malleolus up above that I had to put a small heel lift in…otherwise I’d have no skin left on my malleolus after a couple of runs. Plus, I have a ‘Happy Feet’ insole with a slightly raised heel… I carved out the medial arch support, so otherwise, the insole is flat and doesn’t interfere with pronation.

So, when I put my precision measurement tool in the boot I get a measurement of 9 degrees of total boot board angle and ski binding angle or NRA !!!!!!!

Back to the drawing board…

I have an additional issue with crash space above my instep in front of my ankle. I’ve dealt with that by increasing the tongue padding on the dorsum of my foot. Also, I’ve put a 6mm high-density flat rubber insole on top of the boot board, to raise my whole foot up in the boot. I can’t go any more than that without taking out the liner padding above my toes, so I guess that’s next. If I take out the heel lift, and put in some more high density rubber from heel to toe to lift my whole foot, that will reduce the total boot board angle, raise my foot to reduce the crash space dorsally, and also get my ankle bones up above the irritating shell deviation.

I have to wait for the ski season here to give you feedback…  In the meantime, I’m going to play with varying boot board angle on my force platform. I can put markers on my leg and boot and record the trajectory of the centre of pressure under my boot, relative to my limb segments, as I flex and extend my knee and hip over the boot. I’ll let you know what I see……

……… to be continued


FOOTNOTE

Dr. Bob: “I had some problems with the shell of the boot coming in laterally below the hinge and rubbing on my lateral malleolus, so to get my malleolus up above that I had to put a small heel lift in…otherwise I’d have no skin left on my malleolus after a couple of runs”.

My Comment: It is important to expand the boot shell, if necessary, to ensure the foot is fully supported on the boot board. Heel lifts can create a whole new set of issues.

MICHAEL ON THE TRIALS AND TRIBULATIONS OF RAMP/ZEPPA ANGLE

Opening Comments

When I published my first post on May 11, 2013, A Cinderella Story: The ‘Myth’ of the Perfect Fit (https://skimoves.me/2013/05/11/the-myth-of-the-…sive-perfect-fit/), I had just finished an intense, sustained cognitive effort in the development of a new footwear technology that a cycling shoe called Kinex is based on. The process reinvigorated my passion for leveraging human performance and served as the impetus for me to look critically at issues affecting skier performance. Those who are interested in cycling can view the Kinex shoe at http://www.kinexsystem.com

The philosophy behind Kinex, one that I embrace in my blog, is that the guiding principles are to use pure applied science, intense research protocols and systematic design processes to grow the understanding of how lower limb function can be improved for athletes in modern sports.  The link to the page on Kinex Research & Testing is http://www.kinexsystem.com/research.php

When I started this blog, I knew that the odds were great that there were others out there who were working on some of the same issues that I had been working on since the mid 1970s. One of the key issues I was trying to clarify was the effect of ramp angle, especially Net Ramp Angle (NRA), on skier performance. Since my first post, I made two valuable connections that have served to greatly improve my understanding of this issue. I made one connection with an American (Michael) and one connection with an Italian.

Here is Michael’s latest insights on what I now regard as the most critical aspect of skiing.


ON THE TRIALS AND TRIBULATIONS OF RAMP/ZEPPA ANGLE

I’ve been intently working on this subject of  ‘net ramp angle’ (NR) for many years because I thought it was the cure-all for everyone’s skiing issues. I’ve been skiing on an adjustable delta device for close to 15 years.  I’ll mix in my evolution on this topic to hopefully illuminate the pros and cons of the ongoing discussions.

Here are definitions the way I understand them;

  1. Ramp or drop as it is referred to in shoes: the angle one is standing on in the ski boot in relation to the base of the ski.
  2. Delta:  the angle between the point the ski boot rests on created by the difference in height between AFD on toe piece and the heel piece of a binding (this angle changes in degrees as the bindings are adjusted for larger and smaller boots)
  3. Zeppa: the angle of the boot board that sits into the bottom of the ski boot. (I believe this angle changes with the boot size of the same model.)

Net Ramp Angle (NRA): the sum of these three items is what really counts.

Don’t mix up degrees of delta with the height of the binding toe and heel as measured from the bottom of the ski.  When placed on the same binding, a shorter boot, built to the same specs as a longer boot, will result  in a steeper delta angle for the shorter boot because the binding heel and toe are positioned closer together.  The reason I measure the distance from the bottom of the ski is because the ski is thickest in the middle and tapers towards the ends.  So where one places the midpoint of the boot in relation to the center of the ski changes the delta. A forward position of the binding increases delta because the heel piece becomes higher in relation to the base as the ski becomes thicker. As the toe piece moves forward, the ski gets thinner.  Moving the whole binding rear of center lowers the delta because the effect is the opposite.  This is my argument why moving the binding forward helps some people ski better because it is minutely increasing the delta which may be what they need for the way their boots are set up.  As David says, minute changes in NRA can have monumental effects on skier performance.  As far as I can determine, because of the binding DIN standard, the zeppa is made to same height in relation to the boot sole for all boots instead of at a specific angle for that model regardless of boot length.  This  has to be recognized and compensated for during the fitting process which David clearly has stated in his blog.

Teaching skiing back in the last century I found most skiers were in the back seat.  The really good skiers were over their feet.  I saw a correlation between fore/aft balance and the ability to function athletically on skis.  So I ‘knew’ back then if I could solve the NRA issue everyone could ski better!  The Athletic Skier, printed in 1994, discussed this and promised that a major binding manufacturer would soon have an adjustable binding to deal with this issue.  So as I waited, I learned that one could get skiers forward by placing heel lifts in their boots.  I taught with a pocket full of heel lifts. If a skier was locked on their heels and was interested, we would zip into a lodge and throw in a pair of heel lifts.  Everyone moved forward, but about 25% didn’t like it at all even though to me they looked better balanced.   They said they had more difficulty turning. So we removed the heel lifts.  This puzzled me greatly.   It wasn’t until many years later I understood the reason skiers couldn’t turn  as well was that the heel lifts lock up the skiers feet even when they seemed to have better fore/aft balance.  With the Load Transfer Test, one can figure out if a heel lift is helping or hindering before going skiing.  Note: I have found that anytime one places only the heel on a ‘ramp’ the foot loses mobility so I don’t use them for that purpose anymore.

Some skiers, especially those with a short torso and very long femur, couldn’t fit enough heel lifts into a ski boot to position them in a comfortable fore/aft position.  I started removing the riser plates under the toe pieces of the binding or placing plastic pieces under the heel of the binding and raising that up.  The major problem is it is really hard to find screws that are long enough plus the hunt starts all over if you didn’t guess correctly the first time.  I believe the longest binding screws I can buy currently are only 16mm.  There is a possible solution which I’ve considered, but have not tried, which is to install inserts (like snowboards have) in the skis and then use machine screws cut to length if necessary and don’t want them sticking out the bottom of your skis.  Plastic is easy to purchase or find in cutting boards, old or current credit cards etc.

Here is my disclaimer on bindings;  there is actually quite a bit of ‘play’ allowed in ski bindings which is evidenced when some one clicks in successfully in spite of having a block of snow/ice on their ski boot 1/4″ or more thick.  Use a bit of common sense and if anything looks stressed then back off.  I once had a purchaser of my adjustable plate NOT release during a fall.  The ski shop immediately blamed my device (their new bindings). But it turned out that it was from a poorly done boot sole grind for canting. Many shops take only a few swipes of 1/2 degree each sole material from one side of the boot with each pass without plaining across the whole bottom of the boot leaving it v-shaped.  This skier was then given a new pair of boots without an explanation.  I’m totally opposed to boot sole canting of this type.  Note; after having been ‘professionally’ canted in the past (to 3 degrees at one time) without a foot bed/orthotic and using Manifesto boot fitting methods, I no longer use cants at all!!!  I also feel safer in a binding I have adjusted for NRA than one that leaves me completely out of balance. That to me is the real liability issue

One of my friends who could never seem to get forward enough as the years dragged on with no revolutionary bindings coming to market said, ‘why don’t you build this device yourself?’  Not being the sharpest knife in the drawer I did.  I’ll skip the gory details with two comments before I talk about results; 1) There is a lot of money in patents; if you are a patent attorney.  2)  You know your patent has passed when your mailbox fills up with advertisements for plaques commemorating your patent which you can buy for hundreds of $s.  My device, which I call the BalancEnhancer (BE), is a plate which mounts between the ski and binding and has an adjustment mechanism on one end which can be mounted with the adjuster to the front or back.  This ‘cure all’ actually worked (!) getting me over my feet which relieved so much torque on my bum knee that I could actually hop from one mogul to the next if I so desired.  In my own use and with anyone else willing to try it, we needed to have a NRA up to 10-12 degrees.  At that time, I had foamed injected liners and rock-hard-in-the-arch footbeds which gave me great balance statically in race fit ski boots.  With this combination, I needed a ridiculous NRA to correct my fore/aft balance.  I endured a couple brushes with frost bite and damaged nerves in my toes from that style of boot fitting.  I’m totally opposed to this barbaric method today and now have the warmest feet ever with less liner.

Life was good until I returned to ski the steep bumps the following year and found that I couldn’t get an edge with my left foot.  I finally figured out my left foot was immobilized within the ski boot compared to my right foot.  I solved that issue by first removing the zeppa and then changing to a different brand ski boot based upon the zeppa (whole different dissertation).  Then I found that I HAD TO LOWER the delta!  Let me repeat, as I dropped my heel within the ski boot I HAD to drop the NRA, because the increased mobility in my ankles allowed me to get out of the back seat. I found that was too far forward at that setting.  Leaving out a lot of detail, I currently ski with binding toe and heel pieces at equal height from the base of the ski or the with the toe up to 1/8” higher.  I am not quite sure if that is due to ski construction, terrain or the position of the moon (or my mind) on a given day, but I even have fine-tuned one pair of skis with strips of duct tape.  If I had learned about freeing the ankle glide path earlier, I probably would never have built the BE.  Unfortunately I didn’t time my inventing of the BE very well with the advent of track bindings. So no ski company was interested.  If they were polite, that’s what they said and some more things I don’t need to repeat.  I would hate to see the state of the ski industry if they weren’t so open minded!  A factor they ignored was that the track binding/ski combo still don’t flex as well as an un-mounted ski does whereas the BE isolates the boot and binding from the ski and allows a pure flex so I’d think at least racers would love it.

Due to the integrated bindings and very few flat skis, I had a marketing problem.  Then I was asked by a co-conspirator why  ski boots have a ramp to begin with.  I never thought of that. So during the 2000 mile drive home,  I pondered that question.  I took a pair of boots (the ones with the wrong zeppa) and removed all the ramp angle. I took a pair of other ski boots that I had, cut the toes off, filed them to fit  under the toe of the boot to zero out the ramp, and went skiing.  Worked unbelievable until I got to steep bumps at which time I needed to increase the NRA with the BE.  After that, I built a machine that I could precision grind toe pieces out of plastic (cutting board material).  On a BE mounted ski I would adjust and ski to determine the correct NRA.  The boot would sit on a platform on the grinding machine which is adjusted to equal the NRA.   Then you toss in a cutting board and 2 perfectly carved toe pieces pop out. Since one raises only the toe of the boot, to fit the binding, the new toe piece has to be at the correct angle.   Aside from being a tedious process, it works quite well.  This allows one to use that ski boot in any binding with the same delta angle.  Then a new adjustment like The Skiers Manifesto advises comes along,  one changes one thing such as the ankle glide path and you have to make a new toe piece starting the whole process from scratch.  This hasn’t been an easy cure in my experience.

Prior to my introduction to the Manifesto I had a hip issue. I solved this by loosening my boots to the point where I would hit the cuff just before I hit maximum ankle flex.  When I read this blog, I was stunned at the fact that I wasn’t smart enough to figure out to allow ankle flex years ago. I realized that the whole ramp issue was the culprit; every time I tried to ski or skate in an ‘off the shelf’ configuration I would fall forward on my face due to too much NRA.  I had to buckle the boots tight in order to not fall forward out of my boots.  With the BE and the ability to override the NRA issue, I can actually ski with as much unimpeded ankle glide path needed and use my ankles as they are designed!!  All these adjustments have also allowed me to go from DIN settings of 12-14 and still pre-releasing to a civilized DIN setting of 6 and never pre-releasing.

The bottom line is that David’s methods of boot fitting are the correct way. I went at it backwards by starting with NRA.  First set up the optimum position and mobility of the foot within the ski boot.  Personally, I would like to start with a ski boot with zero ramp. But that’s not going to happen for a while.  So go with David’s recommendation of finding a starting point of ramp as measured using his methods. Then fine tune the NRA per his instructions.  In my experience, every time one changes anything in the ski boot the apparent NRA changes (ANR.)  With over a decade on the BE and hundreds of boot changes, I have yet to perfectly quantify the correct NRA off slope.  I actually tried standing on a piece of plywood in an attempt to find the NRA in-shop.  I didn’t ever fit the boot first with all the knowledge that is shared  in this blog so I can’t say it doesn’t work.  A major boot change occurred recently with no chance until next year to see if it corresponds to what I could feel measuring NRA in the shop.

I have no illusions, part of this is ‘art’ and David’s been ‘painting’ on ski boots for decades so I’m only speaking from my perspective.  I definitely see it as a good place to start and am sure that it will get one close which is a positive and better than what anyone else is doing with ski equipment.  I say ANRA because with my ski boots at about 10% alignment originally, the BE got me to an APPARENT optimal fore/aft balance dictated by the ski boot but still completely misaligned.  I currently find the optimum NRA for bumps and groomers to be different (1-2degrees if I remember correctly), but unfortunately I can’t be positive until tested next season.  I see world cup racers struggle in one discipline and winning gold in others.  It’s all about Net Ramp!

To me ideal ski equipment set up would be as follows;

  • Get the boot set up as perfectly as possible.  By following The Skier Manifesto or have David do the work!!
  • Have a ‘next generation’ BE which would have infinite (not incremental) adjustment to be able to fine tune the delta to the skier’s comfort.  Note; I have that and a number of configurations patented already but am currently trying to figure out how to build an infinitly adjustable prototype that is feasible for my budget.
  • Any time a change is made in the boot, the BE can be adjusted if necessary.
  • Have unbelievable fun skiing!!

My Closing Comments

Based on my most recent experience, I now believe that the essential starting point is for a skier to learn how to assume a strong ski stance. Only after they have acquired a kineasthetic sense of a strong stance, should they attempt to find the correct ramp angle on a device like a Stance Ramp.

I also think it probable that bump skiing requires a different ramp angle than race/recreational skiing. This remains to be established.