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Fore -Aft Balance

post #1 of 24
Thread Starter 
I teach skiing at Deer Valley and I've seen a lot of instructors paying a lot of money having there boots fore aft balance changed with sometimes disastrous results. I have been making footbeds for 25 years and know how small changes in heel height can affect your balance. Can anybody explain to me what and how they are measuring on the foot to come up with their recommendations. I just reread Athletic Skier on the subject and I am still in the dark. Thank You
post #2 of 24
Ankle mobility is one thing to check, binding delta is another, boot forward lean, zeppa ramp angle and flex are others. IMO the key things to remember is that everything has to work as system (the skier, the boot, the footbed, the binding, the ski etc.) and that every skier is different. What works for skier will not always work for the next
post #3 of 24
Quote:
Originally Posted by stevebayne View Post

I teach skiing at Deer Valley and I've seen a lot of instructors paying a lot of money having there boots fore aft balance changed with sometimes disastrous results. I have been making footbeds for 25 years and know how small changes in heel height can affect your balance. Can anybody explain to me what and how they are measuring on the foot to come up with their recommendations. I just reread Athletic Skier on the subject and I am still in the dark. Thank You

Stevebayne,

I believe fore/aft alignment is very important to get right and very few understand how to achieve it.  As JDoyle eluded, there are four primary parameters affecting fore/aft balance which need to work in concert.  Ramp angle, forward lean angle, binding delta angle, and binding mount position all affect our fore/aft balance.

 The methodology I use begins with the foot and matching it's dorsiflexion to the net forward lean angle of the boot then moves outside the boot to look at the lower leg and up the body.  This involves assessing the dorsiflexion range and basically determining if it below average, average, or above average and changing the ramp angle and the forward lean angle of the boot to provide some congruency in the joint while in the static position.  So, if the ankle has limited dorsiflexion it may be necessary to increase the ramp angle and reduce the forward lean to arrive at the desired net forward lean to match the ankle needs.  Conversely, if the ankle is hyper mobile we may need to decrease the ramp and increase the forward lean to meet needs.  Once the net forward lean angle is achieved and offers adequate congruency, I look at the skier clicked into their ski bindings.  Because there is still a wide range of stand height differentials between binding models as well as the boot sole length factor and tib/fib length we may find the knee plumbs out over the toes or possibly back over the forefoot buckles of the boot.  I try to reach a static position with the knee plumbing over the toe of the boots.  This is only a ball park starting position to then go on the hill and test dynamically to fine tune delta and possibly fine tune binding position if possible.

A trained eye can spot instantly if your fore/aft positioning is good or needs work while skiing.  As a skier you can increase your sensitivity of how these parameter changes affect your stance and balance by experimenting yourself.  I regularly carry shims in my parka pockets to experiment on the hill.  It sounds like you have noticed how changing heel lift affects your stance and skiing so I would suggest playing with placing bontex shims (not thicker than 3mm) between your binding and your boot sole, both under the toes, then under the heels to feel the affects.  It is not uncommon to go one way inside the boot and the opposite outside the boot to achieve an optimal position.

Note, I see many misuses of heel lifts and forward lean adjustments.  There are too many variables to list here but as an instructor, I encourage you to learn more and experiment yourself to expand your understanding of this fore/aft plane as it will help your teaching and student success.
post #4 of 24
Thread Starter 
Thank you for the replies. To get a bit more technical, what are the best ways to test ankle dorsiflexion and what are the ranges of degrees between low ,average and high. Is it measured from a weighted or unweighted stance, from 90 degrees, or what? Thanks
post #5 of 24
 Though I do not measure dorsiflexion with a goniometer or digital compass, maybe I should.  I use a very basic technique from a seated position of 90/90/90 thighs,shins,feet and have the person lift their forefoot as high as possible and watch to insure they are not twisting the fore foot.  Then I look at the gap between floor and fifth metatarsal head.  Consideration must also be given to the length of foot as the gap will be proportionately larger for a longer foot to equal the same angle.  With an average length foot (size 9-10) I consider 1 1/2 - 2 fingers space average.  1 or less below average, and more than two, above average.

Other fitters may use different methodology.  I believe Jim Lindsay (Boot Tech) measures unweighted with a goniometer.  

Because it all comes down to how things feel on hill to the skier, I don't get too caught up in precise angles for dorsiflexion, rather get the person in the correct church, the right pew, and maybe the right seat or the one just beside it!
post #6 of 24
Since Bud was kind enough to cite me as a reference, I feel compelled to reply. Even if it is only to repeat what the others have said.

i measure dorsiflexion open chain (non-weight bearing) and as close to STJ (sub-talar joint) neutral as I can maintain. This is to isolate the  TCJ (talo-crural joint) and prevent compensatory motion from creating apparent dorsiflexion. Despite this seemingly complex methodology.
it is really a simple pass/fail test. Ten degrees of motion or more, on to the next step. With less than ten degrees ROM, I repeat the test with the leg extended, if there is a further decrease in motion this will indicate that it is a soft tissue impediment (tight calves/hamstring etc.) as opposed to a structural cause.

As Bud stated, making sure the boots net forward angle does not exceed ROM is important, but not always feasible when the client has 0 degrees (or less than zero) of motion.

I also look very closely at how much knee flexion is created by the whole system. How much weight is distributed on which half of the foot,
and the longitudinal location of the tubercle relative to the foot.

There is no point in looking at lateral alignment until you have established fore/aft balance.

I will also add that if I could change one thing in the ski industry it would be to make ALL bindings flat. This is a tough variable. especially when dealing with someone with multiple pairs of skis.

As long as I am ranting, I would also say that most ski boots have at least enough, if not too much, forward lean. Forward lean is like tequila, some can be a good thing, but more is not automatically better.

Thanks! I feel much better now.

jl
post #7 of 24
great question and all i can do is echo the guys above, in response to jims wish for all bindings to be flat... can we also have them all supplied with a set of assorted thickness shims so we can set up the delta for the individual
post #8 of 24
Thread Starter 
Checking my own dorsiflexion or what I thought was dorsiflexion, I am pretty close to zero. When I try to create dorsiflexion I notice that I can only create it by twisting my forefoot to the outside and rolling my ankle to the inside in a pronated position. That is probably the reason that I have a such a hard time making wedge turns. The more I flex my knee forward toward the tip the more my foot wants to steer to the outside, the straighter my ski goes and I am left trying to steer from the hip socket which is not easy for an old guy.
 Let me see if I understand this, if I have below average dorsiflexion I want more ramp angle and less forward lean which is what I have already have set up. When you say match the net forward lean with the dorsiflexion what are you trying to achieve and what exactly is  net forward lean. Is it ramp angle plus foot bed plus delta and then set forward lean at 90* to that. I realize it is just a starting point.
  One thing that I played with was putting a forefoot varus wedge that lifted my big toe and let me pressure the inside tip more with a little less pronation.
Any help would be appreciated in my quest for balance.
post #9 of 24
I'm not sure I agree with being able to assess ROM on oneself.  But can tell you that in general, I increase ramp angle and decrease forward cuff angle with limited dorsiflexion. I am also of the stiffer or shorter flex range camp, as opposed to a softer boot with a greater range of movement in these instances.

Net forward angle, as I use it, refers to the cuff angle minus the zeppa ramp. This is roughly the amount of ankle flexion required to stand in that boot. External influences such as binding delta, do not increase ankle flexion inside the boot, but do increase knee flexion.

And yes, I would rather have adjustability with binding ramp, as in the race world. But since right now even bindings within the same brand have different angles and it changes with boot sole length (usually in the wrong direction), I would settle for flat.

jl
post #10 of 24
I hope no one minds me getting into the fray a little and possibly with a dissenting opinion.  first let me say great question.  I wish we got more of these and less of which boot to I buy for my 89 year old mother.  Also great that you are interested.  Fore/Aft is hugely important.  Jim and Bud have gone to great pains to explain and I'll agree with Jim when he is uncertain about your ability to gauge it yourself.  However, there is something else happening here that I would like to point out.

In the industry we have always fixed lack of dorsiflexion with heel lifts.  It only makes sense as it moves the foot into a more plantarflexed position.  However, it completely ignores the affect on balance, which may be very detrimental.  There may be differing opinions about which is more important improved ability to flex or improved ability to balance.  I am firmly in the balance camp.  I'm not convinced that large range of motion in the ankle is important in most skiing situations.

Therefore,  you may want to experiment with toe lifts.  If it improves balance and p;icks up the beginning of the turn you may find that the extra ankle mobility is not important.  Also, if you experiment with heel lifts you definitely may want to include binding toe or boot toe lifts to decrease ramp angle.

Lou
post #11 of 24
Lou is absolutely correct and not at all dissenting in my view.

Where indicated, "the gas pedal" is indeed a magic bullet.

If heel lifts were the entire answer the problem would have been solved long ago.

  jl
post #12 of 24
Thread Starter 
What is the relationship between fore aft balance and binding placement on the ski? Do you move it forward or back when considering dorsiflexion or ankle ROM?
post #13 of 24
Impossible to say.  What is the starting position?  As discussed many places on this forum and site, manufacturers' recommended binding positions are not standardized.  The answer to your question is "It depends on the ski, the recommended location and the individual skier".  Look through the Wikis and other places here and you'll find quite a bit that is helpful.
post #14 of 24
Quote:
Originally Posted by stevebayne View Post

What is the relationship between fore aft balance and binding placement on the ski? Do you move it forward or back when considering dorsiflexion or ankle ROM?

I don't really consider dorsiflexion or ankle ROM when determining binding placement.  The ankle issues should be addressed before consideration of binding placement which is the last on my list of the four parameters involved with fore/aft alignment.  Binding placement is all about matching the sweet spot on the ski with the skier's desired leverage position.  As evidenced by many of today's skis with their multiple mounting guide markings and an ever increasing number of binding models which offer fore/aft adjustments (ie: Marker Schizzo, Blizzard's binding rail system), skiers may choose different mount positions based on their skiing preference or ski characteristics.  Basically moving a binding aft of the ski's sweet spot will necessitate the skier's leverage bias to be a bit more forward, while moving the binding mount forward of the sweet spot will move the leverage bias aft.   Without testing it is difficult to prejudge the optimum position.  I do like the adjust on the fly option of the Marker Schizzo which can be moved with a screwdriver or quarter while in the lift line.  Experimentation is key here and will instantly provide you with your preference.
post #15 of 24
stevebayne,

masterfit university offers a 2 day course that would get your stance balancing skills up a notch. it would also be helpfull to see how working pros assess feet, ankle ROM, arch flexibility, cuff alignmnet, knee alignment, fore/aft balance, and basic boot fitting skills,and problem solving, etc,etc,etc... two left this year in november, breckenridge, co and reno, nv.

much more clear mud then reading it here from people you don't know describing skills you cannot see being used.

a great investment in your future as a ski teacher. the ski industry needs more guys on the hill using these tools to help skiers become better.

jim
post #16 of 24
Thread Starter 
I have looked at Masterfit University before and would like to attend. Do you think that it would be worth the money to attend. I would like to get more involved with the bootfitting process and move it out of my garage and look at doing it as a business sideline to compliment my instructing. I have even considered looking for a bootfitter in the Salt Lake area that I could apprentice with. Do you have any suggestions?
post #17 of 24
I use to help with Masterfit U and can vouch for the instruction---you can not beat hands on work experience---you will realize what you don't know the first time you attend and it will make sense about the 3rd or 4th time you spend money for the tuition.  We noticed as instructors that many folks attended 5 and 6 times in a row(yearly). 

Good Luck,
post #18 of 24
Yes, I think that going to Masterfit University would benefit you as a ski teacher and bootfitter.

I teach at Masterfit so you have to discount my recommendation by 23.5%. Ask Bud Heishman or CEM, or Philpug if they think there is value. These guys have attended a MFU in the last 2 seasons.

Brent Amesbury is in PC, a good man to bounce your apprentice idea off of. We are always looking for an eager apprentice in Tahoe.

jim
post #19 of 24
 MFU is the best educational  opportunity for a boot fitter I am aware of!  I learn something every time!
post #20 of 24
i'll second that, an all round good learning experience and good crack too
post #21 of 24
Quote:
Originally Posted by starthaus View Post

Yes, I think that going to Masterfit University would benefit you as a ski teacher and bootfitter.

I teach at Masterfit so you have to discount my recommendation by 23.5%. Ask Bud Heishman or CEM, or Philpug if they think there is value. These guys have attended a MFU in the last 2 seasons.

Brent Amesbury is in PC, a good man to bounce your apprentice idea off of. We are always looking for an eager apprentice in Tahoe.

jim

I was going to post my experiences but not being at the level of the "Masters" here, I thought it would be inappropriate. But since I was asked...The knowledge I received at just the 2 day associate clinic was incredible. I have added multiple facets to my fitting process with customers. Fore-Aft balance in now one of the key areas I have added to my fit process. I can see how, as an instructor, this class could be a huge asset to you in being able to analyze a students foundation and ability to get to the next level in their skiing. 
post #22 of 24
 I heard Phil is giving a clinic this season on "ski pole calibration"?
post #23 of 24

Fore -Aft Balance

Quote:
I will also add that if I could change one thing in the ski industry it would be to make ALL bindings flat. This is a tough variable. especially when dealing with someone with multiple pairs of skis.

As long as I am ranting, I would also say that most ski boots have at least enough, if not too much, forward lean. Forward lean is like tequila, some can be a good thing, but more is not automatically better.
absolutely!!!
post #24 of 24

Fore -Aft Balance

I think one point has been overlooked here.  Ankle range of motion and fore/aft balance are certainly connected.  Consider for a moment that a heel lift in the shell to open the ankle joint is a part of balancing the foot.  If a skier is limited in the ankle joint and cannot move forward enough to pressure the tongue of the boot, or the skier does move forward and the result is the heel lifting off the boot board and increasing pressure on the "ball" of the foot then a heel lift is certainly beneficial.  This helps the skier feel the whole foot rather than just the heel or just the "ball".  Just adding toe lift to the shell or under the binding toe piece does not address the issue of "burning balls" or "tail gunning" due to limited ROM.  I believe fore/aft balancing is done after the foot is balanced and that the objective is to give the skier a comfortable neutral stance from which the skier has the ability to move forward.
Edited by taoscowboy - 10/17/09 at 5:10pm
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