Help Needed: Help Understanding Correct Stance/Posture

[Skisailor]

The problem is: I truly don't believe that heel lifts and increased ramp angles shift the COM forward for most people. Just the opposite in fact. We've had this conversation before on this forum.

Counterintuitively, when you lift the heel, most people are forced to move BACK to stay in balance. That's why lifting the toes/forefoot in ski boots has become so popular. When you lift the forefoot, most people move forward to compensate and stay in balance.

In my experience, skiers with heel lifts and/or excessive ramp angle tend to struggle to get out of the "back seat" while skiing.

Heel lifts seem like a necessary addition for those with limited dorsiflexion. But for most people, IMHO, they should be avoided.

The question I would ask everyone is: do you need heel lifts in your sneakers to play tennis? Or softball? Or golf? Or basketball? If not, then you don't need them in your ski boots. Skiing is a sport that is played from the balls of the feet - like almost every other sport.

It's that simple. We must all determine how to flex our ankles, knees, and hips to stay balanced over the ball of the foot. It's an individual process - different for each of us based on a whole host of factors - but it's really not that complicated, IMHO.

 

[Obrules15]

The problem is: I truly don't believe that heel lifts and increased ramp angles shift the COM forward for most people. Just the opposite in fact. We've had this conversation before on this forum.

Counterintuitively, when you lift the heel, most people are forced to move BACK to stay in balance. That's why lifting the toes/forefoot in ski boots has become so popular. When you lift the forefoot, most people move forward to compensate and stay in balance.

In my experience, skiers with heel lifts and/or excessive ramp angle tend to struggle to get out of the "back seat" while skiing.

Heel lifts seem like a necessary addition for those with limited dorsiflexion. But for most people, IMHO, they should be avoided.

The question I would ask everyone is: do you need heel lifts in your sneakers to play tennis? Or softball? Or golf? Or basketball? If not, then you don't need them in your ski boots. Skiing is a sport that is played from the balls of the feet - like almost every other sport.

It's that simple. We must all determine how to flex our ankles, knees, and hips to stay balanced over the ball of the foot. It's an individual process - different for each of us based on a whole host of factors - but it's really not that complicated, IMHO.

It's not counterintuitive it makes perfect sense. The fact that inappropriate heel lifts cause sitting back too far is proof that they change the location of the center of mass. If you feel off balance you shift to counter it, so if a heel lift has you shifted too far forward, then you sit back to compensate.

The other issue is how much someone needs. I need a boot that has 16 degrees of forward lean, a 5mm heel lift and 6 mm of ramp delta in my skis. If I have 20 degrees of forward lean, it causes me to sit back, but the boot with 12 was not enough (it's a boot that advertises itself as decreasing the sitting back, by the way, it just doesn't do that for me). A 1 cm heel lift screws up how my boot fits, and no lift is a disaster. 3cm of ramp delta is not enough but 10cm causes me to sit back as well. I've tested and been filmed.

Throughout my posts, I've specifically referenced that it is certain body types and biomechanical factors which can benefit from heel lifts and increased RA. The video link I posted specifically talks about how changes in proportion affect how a body moves. I've never suggested that all people benefit from the interventions.

Honestly, it's this kind of thinking that kept me miserable on skis for years. Even with all joints flexed (and they do except my ankles) my COM is NOT over the balls of my feet, and all of the instructor yelling in the world never changed that. What did change it was someone taking measurements and figuring out that the way I was built changed what I needed. My apologies that it's just not that simple for me. But I think I should still be allowed to enjoy skiing even if I'm not like you, and luckily there are people that agree.

Instead of arguing why aren't we trying to figure out a better way for the industry to identify who will benefit, so skiers that need lifts will get them and those that don't, won't. It seems to me that figuring out ways for a larger proportion of the population to enjoy skiing benefits everyone in the long run.

 

[Skisailor]

It's not counterintuitive it makes perfect sense. The fact that inappropriate heel lifts cause sitting back too far is proof that they change the location of the center of mass. If you feel off balance you shift to counter it, so if a heel lift has you shifted too far forward, then you sit back to compensate.

The other issue is how much someone needs. I need a boot that has 16 degrees of forward lean, a 5mm heel lift and 6 mm of ramp delta in my skis. If I have 20 degrees of forward lean, it causes me to sit back, but the boot with 12 was not enough (it's a boot that advertises itself as decreasing the sitting back, by the way, it just doesn't do that for me). A 1 cm heel lift screws up how my boot fits, and no lift is a disaster. 3cm of ramp delta is not enough but 10cm causes me to sit back as well. I've tested and been filmed.

Throughout my posts, I've specifically referenced that it is certain body types and biomechanical factors which can benefit from heel lifts and increased RA. The video link I posted specifically talks about how changes in proportion affect how a body moves. I've never suggested that all people benefit from the interventions.

Honestly, it's this kind of thinking that kept me miserable on skis for years. Even with all joints flexed (and they do except my ankles) my COM is NOT over the balls of my feet, and all of the instructor yelling in the world never changed that. What did change it was someone taking measurements and figuring out that the way I was built changed what I needed. My apologies that it's just not that simple for me. But I think I should still be allowed to enjoy skiing even if I'm not like you, and luckily there are people that agree.

Instead of arguing why aren't we trying to figure out a better way for the industry to identify who will benefit, so skiers that need lifts will get them and those that don't, won't. It seems to me that figuring out ways for a larger proportion of the population to enjoy skiing benefits everyone in the long run.

Certainly didn't think we were arguing!


I was just sharing my own observations, perspective and experience, just as you have.

 

[Obrules15]

It's that simple. We must all determine how to flex our ankles, knees, and hips to stay balanced over the ball of the foot. It's an individual process - different for each of us based on a whole host of factors - but it's really not that complicated, IMHO.

After 33 years (on again off again) of failure with instructor after instructor telling me the same things, I definitely perceived that statement as somewhat judgemental. I understand if it wasn't meant that way.

 

[Skisailor]

After 33 years (on again off again) of failure with instructor after instructor telling me the same things, I definitely perceived that statement as somewhat judgemental. I understand if it wasn't meant that way.

Not in the least. As I said - it's certainly an individual process.

But I do have an opinion about heel lifts in particular, because of the history of their pervasive use by boot fitters and boot salespersons as a band aid fix for women who have been sold boots that simply do not fit properly. And I believe that heel lifts cause more problems than they fix for the vast majority of women who use them. So I think it's great if they have worked for you as part of your setup. But I wanted to raise a concern that for most of us - we should approach any recommendation for the use of heel lifts or aggressive ramp angles with caution.

The other main point I wanted to emphasize for those who may have less experience than you with these issues, is that the COM is not a body part and is most certainly not fixed in place by our anatomy. We have the ability to move it by the way we flex our joints - ankle, knee and hip, for example.

 

[Obrules15]

Not in the least. As I said - it's certainly an individual process.

But I do have an opinion about heel lifts in particular, because of the history of their pervasive use by boot fitters and boot salespersons as a band aid fix for women who have been sold boots that simply do not fit properly. And I believe that heel lifts cause more problems than they fix for the vast majority of women who use them. So I think it's great if they have worked for you as part of your setup. But I wanted to raise a concern that for most of us - we should approach any recommendation for the use of heel lifts or aggressive ramp angles with caution.

The other main point I wanted to emphasize for those who may have less experience than you with these issues, is that the COM is not a body part and is most certainly not fixed in place by our anatomy. We have the ability to move it by the way we flex our joints - ankle, knee and hip, for example.

If you watch the videos I posted they are specifically directed at individualizing recommendations as opposed to making blanket statements and recommendations based on industry norms. As I say in almost every post, I am freaky weird. I am 5'3 3/4' but need pants that fit someone who is 5' 10", and my feet still dangle occasionally in chairs (I have to hop off the Jordan Bowl lift at SR), that translates to a super short torso, short tib/fib, and looonnnnnggg femur. My setup would be a disaster to the vast majority of skiers.

I don't expect that I should have been easy to fit, as it wouldn't be appropriate for the vast majority of skiers. My frustration has stemmed from the difficulty I've had getting enough information to figure out what's going on. The research to back up the recommendations for female specific setup and the theories involved are a little sparse.

There are a whole bunch of people who throw heel lifts in boots, but as far as I can tell most don't understand why, so when they don't work no one knows how to troubleshoot. If you properly understand what you're trying to accomplish with heel lifts you'll understand why you "might" have trouble with a rigid boot or that if you've now got a back shifted COM it's probably either too much or inappropriate. If you understand that binding ramp angle has a different effect than an in boot heel lift because a heel lift actually opens up the joint, you make better choices and can troubleshoot better.

Another issue with heel lifts is their use in the past to compensate for the lack of short cuff boots for women. I remember getting fit for a boot in '03 and the shop didn't have a short cuff boot so they tried to use a heel lift to raise my leg out of the boot so it wouldn't go numb. I don't know how pervasive that practice was but talk about a misuse of technology.

Even to the point of forward lean. Lange touts the greatness of their natural stance boot as do many great boot guys I've spoken with. It helps to prevent that compensatory heel sitting you were talking about earlier. But a skier with proportionately longer femur lengths is not appropriate for this boot because they are going to need to use their ankle ROM to stay centered.

What I advocate is a deeper, more thorough understanding of the issue so we can move away from an "all women need or don't need x" mentality, because as I said in an earlier post, even if 80% of women need something, that still leaves 2/10 women who walk through the door who won't.

 

[snow addict]

Not in the least. As I said - it's certainly an individual process.

But I do have an opinion about heel lifts in particular, because of the history of their pervasive use by boot fitters and boot salespersons as a band aid fix for women who have been sold boots that simply do not fit properly. And I believe that heel lifts cause more problems than they fix for the vast majority of women who use them. So I think it's great if they have worked for you as part of your setup. But I wanted to raise a concern that for most of us - we should approach any recommendation for the use of heel lifts or aggressive ramp angles with caution.

The other main point I wanted to emphasize for those who may have less experience than you with these issues, is that the COM is not a body part and is most certainly not fixed in place by our anatomy. We have the ability to move it by the way we flex our joints - ankle, knee and hip, for example.

I generally agree with what you say about heel lifts - they do not work for everyone, but COM is actually fixed in our bodies, we can move it by flexing etc., and it will change it's spatial position, getting higher/lower etc., but it will still be in the same spot in our bodies.

My perception of "aggressive" ramp angles has changed a lot after I started using Dynafit Radical bindings. The ramp is 15 mm, and initially I hated the feel - it was indeed like skiing while wearing stilettos. I always had to be mindful about my body position - I still have but I am getting used to it. I do toy with an idea of shimming the toe pieces, but since nothing aches, I have a good control and don't fall over I am a little hesitant. I am afraid that if I shim the bindings it will create some other issues and make climb worse - lifting toes by almost 1 cm to bring delta to a respectable 6 mm seems like a lot. I like my touring setup overall, once I was initially fitted into touring boots 3 years ago not once I went back to a fitter for any sort of adjustments so would prefer to keep it this way...
Anyway, I don't notice the difference going from my almost neutral Marker Tours to Look Pivots with a 6mm delta. They both feel "flat" compared to Radicals.

 

[Skier31]

Good discussion. What is frustrating for me, is I went to a highly respected boot fitter and while I have great fitting boots with proper canting, he did not ever ask me what bindings I had nor did he suggest I might want to check ramp angle etc. I spent a couple of years trying to do things that were precluded by equipment issues.

 

[bounceswoosh]

Good discussion. What is frustrating for me, is I went to a highly respected boot fitter and while I have great fitting boots with proper canting, he did not ever ask me what bindings I had nor did he suggest I might want to check ramp angle etc. I spent a couple of years trying to do things that were precluded by equipment issues.

I've still never had a fitter ask about this, even the ones I think are great. But I also have had only minor issues with flex and none with staying out of the backseat. The first 15 issues I bring up all have to do with fit and then wanting a more upright boot. If I gwt a chance, I'll ask my current fitter if it's in his mental checklist. Like mount point, I think some people are more sensitive to changes in ramp angle than others.

 

[Gloria]

I generally agree with what you say about heel lifts - they do not work for everyone, but COM is actually fixed in our bodies, we can move it by flexing etc., and it will change it's spatial position, getting higher/lower etc., but it will still be in the same spot in our

This is along the lines of what I am trying to say with the two different squats. By adjusting the angles of different body parts I can achieve a similar outcome in 2 different ways using the same body proportions. The issue seems to be more along the lines of the strength flexibility continuum. For me my ankle dorsiflexion is way to far on the flexibility continuum lacking strength and stability, where for others they are more imbalanced on the strength side lacking flexibility. I had a bad ankle sprain almost two years ago and that ankle has been sprained a million times before and I don't think the ligament is ever going to be the same. I didn't ski much last season but my issues were on the same side as the ankle. I didn't raise the heel in the boot, in fact I have 2 pieces of cardboard under the toe of the footbed to flatten out the angle built into the boot. The cuff just has a bit more lean which is working for me because I am lacking strength in that range of motion. I find a raised heel causes me to throw my shoulders back and causes lbp. I don't doubt heel lifts might work for some people but I can never quite wrap my head around increasing plantar flexion to assist with better dorsiflexion. I understand well the weight shift of the entire body, which is why I throw my shoulders back, but I don't see where it helps one bend the ankles better.

 

[Skisailor]

I generally agree with what you say about heel lifts - they do not work for everyone, but COM is actually fixed in our bodies, we can move it by flexing etc., and it will change it's spatial position, getting higher/lower etc., but it will still be in the same spot in our bodies.

I disagree with this understanding. Depending on our body position, the COM may not even be within the body at all. Where is the center of mass of a hula hoop?

 

[Skisailor]

I disagree with this understanding. Depending on our body position, the COM may not even be within the body at all. Where is the center of mass of a hula hoop?

Thinking about it another way - if you are standing with arms at your sides, then you raise them over your head, do you think the COM moves? Or is it "fixed in our bodies"?

 

[snow addict]

I though we were talking about a body. COM is the point on an object at which the weighted relative position of the distributed mass sums to zero, i.e. it is the point on our body about which it rotates. It cannot be by definition outside of our bodies, because then distributed mass cannot sum to zero.

 

[Obrules15]

, but I don't see where it helps one bend the ankles better.

It starts the joint out in extension, therefore the distance traveled before full flexion is reached is increased even though the actual ROM is not changed.

I'm struggling to come up with a good metaphor but it's somewhat similar to what you can do if you have a plane that needs a longer runway. If the plane starts in the same spot as all others and can end the run at a point further away from the usual places that's one way (equivalent to someone with increased ROM), or it can start at a point before other planes would start, in essence back up and start the run early and end at the normal spot.

The heel lift allows you to start dorsiflexion earlier, therefore giving you an equivalent ROM to someone with normal ROM and allowing you more options to make shifts in your weight.

 

[Skisailor]

I though we were talking about a body. COM is the point on an object at which the weighted relative position of the distributed mass sums to zero, i.e. it is the point on our body about which it rotates. It cannot be by definition outside of our bodies, because then distributed mass cannot sum to zero.

That Wikipedia definition refers specifically to a "rigid body" which is unchanging. Not to a human body which can move and assume all kinds of positions. But we are really getting far afield here.

The main tie back to skiing is to understand that we are not stuck with a poorly positioned COM based on anatomy. We can move it around by flexing our joints and positioning our appendages.

We are mainly interested in how we position the COM relative to the position of our feet.

 

[Obrules15]

I though we were talking about a body. COM is the point on an object at which the weighted relative position of the distributed mass sums to zero, i.e. it is the point on our body about which it rotates. It cannot be by definition outside of our bodies, because then distributed mass cannot sum to zero.

Think about what happens to where those forces are located when we lift one leg up completely parallel to the ground or pull our legs into crossed legged sitting with the knees in front of the pelvis.

You are right, the COM is fixed in a fixed object, but it is determined by an objects' shape. Therefore as something changes shape (bends/folds/contorts, etc.) the location changes.

And the best I can say about location of COM is that it's pure physics which any sane person knows makes no so sense, so yes the COM can be located in a point outside the body. Maybe look at a contortionist to see where those points could be. The COM of a hula hoop *must* be in the middle, as must the COM of a contortionist in a deep back bend with close hands and heels (ouch) or downward facing dog in yoga.

 

[Ursula]

my 2 cents before I will head to the mountain.

The CoM is changing with every move we make. Have you ever sat on a swing, not moving, and then used your legs and torso to start the swing on your own? Or do you need someone to give you a push? If you are capable of starting the momentum on your own - you used your ability to move the CoM for doing it. Congratulations.

(got this image from https://sites.google.com/site/hsa2012vikram07/research )

The CoM does NOT have to be inside the Mass.

Here comes a contortionist, she made a Hula Hoop out of herself.

picture courtesy of https://www.gettyimages.com/detail/...st-inside-the-box-royalty-free-image/72472038
I just added the red dot for the approximate CoM

Next topic: why do heel lift help people with limited dorsal flexion? Well, sort of because you use some of the range of plantar flexion to add it to the dorsal flexion.

Now I will head up to the mountain and keep my CoM forward and hopefully over my feet.
Have a fun day ladies.
Ursula

 

[Gloria]

It starts the joint out in extension, therefore the distance traveled before full flexion is reached is increased even though the actual ROM is not changed.

I'm struggling to come up with a good metaphor but it's somewhat similar to what you can do if you have a plane that needs a longer runway. If the plane starts in the same spot as all others and can end the run at a point further away from the usual places that's one way (equivalent to someone with increased ROM), or it can start at a point before other planes would start, in essence back up and start the run early and end at the normal spot.

The heel lift allows you to start dorsiflexion earlier, therefore giving you an equivalent ROM to someone with normal ROM and allowing you more options to make shifts in your weight.

Yeah, it seems it would be more appropriate to help the person achieve the correct range then back them up just to give them more range that still doesn't hit the bullseye.

 

[Obrules15]

Good discussion. What is frustrating for me, is I went to a highly respected boot fitter and while I have great fitting boots with proper canting, he did not ever ask me what bindings I had nor did he suggest I might want to check ramp angle etc. I spent a couple of years trying to do things that were precluded by equipment issues.

Yep, and remember there are skis touted for women (or used to be with a reverse binding angle-talk about ways to mess someone up). My bootfitter measured my bindings and that was the first time I'd ever seen or heard about it. She had to measure because the iinformation is not usually available. I've tried to go back and reconstruct what I've skied on in the past and in 99% of the cases the info is just not available.

These things have huge effects on our skiing, why is that information so difficult to get accees to and why do so few of even the best bootfitters understand this?

 

[Obrules15]

Yeah, it seems it would be more appropriate to help the person achieve the correct range then back them up just to give them more range that still doesn't hit the bullseye.

Unless they can't.

There are a whole bunch of structures in the foot whose relationships are way more complex than generally understood. While flexibility can be gained by stretching, there are more factors in play than whether someone actively tries to improve flexibility. I've done wall sits and ankle flexibility exercises since I rowed crew in college. I can increase my ankle flexion to a certain point then it stops.

Joint ROM can be affected by the soft tissues but also the shape of the bony interfaces. Your elbow does not move past parallel because there's kind of a locking mechanism, some people have other joints like that which impede movement.

It's really a mistake to think *everything* can be solved in the gym. Different peoples' tissues have different levels of collagen and elastin, etc., which affects what we can do. Research has shown stretchy people are more likely to have pelvic organ prolapse (female organs fall out when you age). So individual flexibility is a way more complex process than most realize.

I do need to add that we all can and should improve our flexibility with the appropriate physical regimen but we can't all get to the same level of flexibility, not to mention it takes time so if a new skier tries to take up the sport they're supposed to be sent away to get in ski shape for a season before they're allowed to come back?

Everybody is at least a little different in terms of their natural gifts. Now for me I have the hardest time understanding how some people can't understand math and science. Biostatistics-easy peazy, Calculus- a breeze, Biochemistry - no problem, Literature 101 - PROBLEM.

So just like those things we all have different aptitudes, I don't use a calculator to balance my checkbook, but am looking for a good writing/grammar program, because clearly I need that, I'm strong so don't need help there, but do need some flexibility aids.

What if I tried to take away your calculator?