Dorsiflexion and its role in skiing

[Wilhelmson]

Ok, so when do we want our ankles opened and closed on a groomer? Btw I was horrible in Latin. The verbs drove me crazy.

 

[James]

Not really. Pictures are the result. How do we know that open ankle rec skier didn't end up closed later in the turn? ( I'm betting not)

Part of this is what people are doing, actions. There's the verb and the noun form of this word. Plus two types of verb. It's all one big state of confusion unless people specify what they're doing and how they're using the term.

 

[Mike King]

Might we have a “this thread is worthless WITH pictures” emoticon? You can’t tell diddly with pictures — you need video. Not one of those racers ski in those erect positions and we can’t tell how the joints are moving from a static photograph.

 

[LiquidFeet]

....How do we know that open ankle rec skier didn't end up closed later in the turn?....

....You can’t tell diddly with pictures — you need video. Not one of those racers ski in those erect positions and we can’t tell how the joints are moving from a static photograph.

C'mon guys. You can tell. You know which skiers in those still shots are experts who manipulate the ankles skillfully, and which are in the "needs work" category ... even from one still shot you can tell. You know this stuff. Stop being coy.

 

[markojp]

Ankles open or closed? What do the skis/snow say?

 

[LiquidFeet]

Well, we can't tell about shin-ski tilt from the camera angle. So the photo does not directly tell us about the amount of dorsiflexion.

So you're right, we must look at the snow spray. It's coming off the skis all the way from the initial contact point at the tips back to at least the waists. We can't see the tails. It's spraying outward and somewhat back. That indicates that the skier has directed pressure to the tips as well as the waists and is going in the direction the skis are pointing. Slicing dominates this turn, not rotation of the skis across the snow.

So... ankles are most likely closed allowing the body to hover over the skis somewhere in front of the toe pieces of the bindings. Lower legs are inclined into the turn to establish a strong edge angle, The skis are not heading in the same direction as the corduroy, so we are most probably looking at the apex of a turn, slightly after the fall line.

We can see that the skier is not particularly angulated since the thighs are not at much of a different angle from the shins.... thus significant pressure/weight is on the inside ski which is confirmed by the amount of snow spray coming off its shovel.

Hands are low. This skier is not skiing like Ted Ligety, rushing through the gates. This skillful skier is taking it easy, casually cruising at high-ish angles, on a pretty clean groomer with the kind of soft snow I wish we had more often here in New England.

 

[dbostedo]

But, why are the toes a useless appendage that don't need contact with the ground plane?

I'm not sure where I or anyone else said this.

 

[James]

Ankles open or closed? What do the skis/snow say?

View attachment 75134

Mr Head looks good. Pass. Probably a < 1% skier. Meaning top. Think his toes are down?

C'mon guys. You can tell. You know which skiers in those still shots are experts who manipulate the ankles skillfully, and which are in the "needs work" category ... even from one still shot you can tell. You know this stuff. Stop being coy.

It's not coy. We've talked about this a million times. I thought the thread was about what people do inside the boot.

But, I agree with you about Mike. He's seen those shots plenty. Dude, what's up?
Ankles go in a range. Unless your religion says they're always closed.

I'm not sure where I or anyone else said this.

The toe lifters are saying this. Toes are for closing the ankle apparently. So, the disembodied head of Red Dawn is letting you know it's an issue.

 

[Mike King]

It's not coy. We've talked about this a million times. I thought the thread was about what people do inside the boot.

But, I agree with you about Mike. He's seen those shots plenty. Dude, what's up?
Ankles go in a range. Unless your religion says they're always closed.

The toe lifters are saying this. Toes are for closing the ankle apparently. So, the disembodied head of Red Dawn is letting you know it's an issue.

Well look at these photos:

No dorsiflexion while skiing (ankles open), recreational skier:
View attachment 75115

Dorsiflexion (ankles closed) while standing around, racers (experts) hanging out on the boot tongues:
View attachment 75120 View attachment 75121
View attachment 75116

Those guys do not ski in those positions. So the photos don't tell us diddly.

https://skimoves.me/2014/03/05/the-birdcage-experiments-data-3/

And instrumented data seems to show that WC skiers in the 90's don't exert much force on the forward cuff of the boot.

Mike

 

[geepers]

Why is your goal to pressure the front portion of the ski? How do you think pressuring the front of the ski is affecting ski performance?

Haven't seen an answer to your question yet.

Anyone else seen this? From the Elan shaped ski designer himself -Jurij Franco

 

[Mike King]

Haven't seen an answer to your question yet.

Anyone else seen this? From the Elan shaped ski designer himself -Jurij Franco

Exactly. So why would we want to pressure the tip?

 

[James]

Well look at these photos:



Those guys do not ski in those positions. So the photos don't tell us diddly.

https://skimoves.me/2014/03/05/the-birdcage-experiments-data-3/

And instrumented data seems to show that WC skiers in the 90's don't exert much force on the forward cuff of the boot.

Mike

Well there were no photos.
It's one moment. The guy is in transition and looks like he's in a chair. He's in the float phase.
However, look at this photo of a horse galloping. Untill Edward Murybridge, people didn't belive that's what a galloping horse looked like with all hooves off ground.
So we could say "horses do not run in those positions". Abd we would be wrong.

Nice on the Birdcage experiment data!
Don't know how to interpret the scale. Apparently he's not lifting the top of his foot either. "Top instep" has no force recorded.

 

[dbostedo]

The toe lifters are saying this. Toes are for closing the ankle apparently.

"Lifting the toes" has always been clear to me that it's just a cue that works for some people to get them to move forward and close the ankle.

That's the context I was talking about in my last post. Is there anyone out there who has ever heard the advice to lift your toes, and it hasn't had that context, and they thought you literally were supposed to lift your toes?

 

[markojp]

.... thus significant pressure/weight is on the inside ski which is confirmed by the amount of snow spray coming off the inside ski.

Weight and pressure on the outside, forebody pressure on the inside. Very keen, quality observations in your post above, LF.

 

[geepers]

Exactly. So why would we want to pressure the tip?

Anyone??

"Lifting the toes" has always been clear to me that it's just a cue that works for some people to get them to move forward and close the ankle.

That's the context I was talking about in my last post. Is there anyone out there who has ever heard the advice to lift your toes, and it hasn't had that context, and they thought you literally were supposed to lift your toes?

I understand it and was 1st shown it as the means to ensure the heel remains engaged, balance point being just at the back of the arch, just ahead of the heel. Light shin contact with the boot front as a reference point. (i.e. NOT crushing) That was in a CSIA L2 course and the course convener had us ski a couple of runs with toes raised. He then 'forgot' to tell us to stop lifting out toes and after another couple of runs 'appeared' to notice the pained facial expressions. Then told us it was a drill and there was no need to ski with toes raised all the time.

Jonathan Ballou has quite a bit to say about TA, toes and heel in this interview - How to take your skiing from good to awesome Part II.

Rough transcripts of some relevant parts (partly summarised):
Foot platform in boot (around the 5 minute point)

Best way to start with this is the foot/boot interface which allows us to control the ski, manage forces and get the performance we're looking for. To that we need a sound structure.

Static drill: stand up at home and do 2 body weight squats, noting where the weight is and isn't on the feet. The weight will predominantly travel through the heel - the balls of the feet will stay in contact with the ground. Now imagine lifting an extra 50kg or 100kg? Would we transfer that extra weight to the balls of the feet or leave it over the heel, over the place of power? Obviously over the heel as anything else would be weak.
This is why ski racers (who think about these things) do lots of squats from the heel.

So our structure is a tripod: our heel, the ball of the foot and the part under our little toe (the 5th metatarsal-phalanges joint).

Setting up for transition there's going to be primary pressure on the heel, then it does move forward to the ball of the foot. But not at the expense of the heel. We don't get off the heel and push into the ball. As we move forward weight gets levered forward onto the front of the foot but it still travels through the heel. If it doesn't we lose that base of support that allows us to get the power and manage the forces.
The key here is shin/boot cuff.
If we are going to put our weight through our heel we are going to have to get forward from somewhere else, as forward is darned important in skiing. How we move forward is more important than that we did it - if we move forward by pushing our toes down and pushing into the ball of the foot a lot it's going to result in us going back. If we stay on the heel and flex the ankle forward by engaging the Tibialis Anterior (TA) it pulls us forward so the shin contacts the boot tongue. The body mass is still supported by the heel but we now have a lever to drive the front of the ski.
​

And around 9:30...

Engaging the TA lifts the front of the toes. But note...it's an exercise, it's not the outcome. It's pretty hard for most people to use the TA to drive their shins forward. Two ways to drive the shin into the cuff of the boot:
1. Use our body weight and lean forward. But if we do this, our heel comes up. So it's not so effective to achieve what we want.
2. The other way is to sink downward, more into the heel and engage the TA to pull the shin forward. But this has to be learnt as it's not a big, powerful muscle. The easiest way to engage the TA is to lift the top of the toes. But as soon as we get good at this, leave the toes flat on the ground for best foot platform.​

Note that in this interview JB seems to be an advocate of using the boot front to pressure the tip. I worked a great deal on that this season and found it counter-productive. Just end up too forward and then have to work it back through the turn. I now aim to stand in the middle of the ski throughout - there's still fore/aft movement but much, much less than I was attempting. No tongue crushing. (YMMV.)

 

[Skisailor]

“1. Use our body weight and lean forward. But if we do this, our heel comes up. So it's not so effective to achieve what we want.”

I’ve heard this interview with JB and had a lot of eyebrow raising moments as a result. But the above quote is the one that just seems beyond ridiculous to me. Why he thinks that balancing with our weight “forward” would necessarily cause the heel to come up is beyond me. Not to mention that it makes me question his bootfitter! Lol.

It is absolutely possible (and in my book desirable) to center our weight over the forefoot/ball of the foot while maintaining firm contact of the heel on the boot sole.

And depending upon how we decide to position our torso over our feet by using different degrees of flex in our ankles, knees and hips, we can accomplish this with either an open or closed ankle.

 

[markojp]

“1. Use our body weight and lean forward. But if we do this, our heel comes up. So it's not so effective to achieve what we want.”

I’ve heard this interview with JB and had a lot of eyebrow raising moments as a result. But the above quote is the one that just seems beyond ridiculous to me. Why he thinks that balancing with our weight “forward” would necessarily cause the heel to come up is beyond me. Not to mention that it makes me question his bootfitter! Lol.

It is absolutely possible (and in my book desirable) to center our weight over the forefoot/ball of the foot while maintaining firm contact of the heel on the boot sole.

And depending upon how we decide to position our torso over our feet by using different degrees of flex in our ankles, knees and hips, we can accomplish this with either an open or closed ankle.

... and posting in the bolded and underlined something that he'd probably not disagree which sounds like disagreeing for the sake of being disagreeable. He's talking to a bunch of folks who DON'T ski from inside their boots ( a radical idea for many instructors), and flexing the ankle iby folding over the top of the skis rather than maintaining functional cuff contact/flexing evenly through all the joints (ankles,knees, femur head/pelvis, spine), and all the commensurate problems with ski/snow interaction and outcomes. I'm sure Jonathan has his boot fit well dialed in. Suggesting otherwise just sounds silly.

 

[Rod9301]

“1. Use our body weight and lean forward. But if we do this, our heel comes up. So it's not so effective to achieve what we want.”

I’ve heard this interview with JB and had a lot of eyebrow raising moments as a result. But the above quote is the one that just seems beyond ridiculous to me. Why he thinks that balancing with our weight “forward” would necessarily cause the heel to come up is beyond me. Not to mention that it makes me question his bootfitter! Lol.

It is absolutely possible (and in my book desirable) to center our weight over the forefoot/ball of the foot while maintaining firm contact of the heel on the boot sole.

And depending upon how we decide to position our torso over our feet by using different degrees of flex in our ankles, knees and hips, we can accomplish this with either an open or closed ankle.

Of course it's possible to have your weight over the ball of the foot and still maintain heel contact.

But why?

You are able to withstand a lot higher forces they the arch/heel and still maintain pressure on the ball of the foot.

Sounds similar, but it's completely different.

And you pressure the tips of your skis by pulling the feet back.

 

[Rod9301]

Btw, the reason for pressuring the ski tips is so you can vary, or tighten the turn radius.

 

[Mike King]

Btw, the reason for pressuring the ski tips is so you can vary, or tighten the turn radius.

Wouldn't a more effective way to tighten or vary the turn radius be to increase or decrease edge angle?