Dorsiflexion and its role in skiing

[Steve]

Technology - Ski

www.lib-tech.com

 

[LiquidFeet]

You do? Really? In all planes? Not challenging, just thinking aloud. I feel like I spend thought and energy doing stuff with my ankles. For example, trying to close them at certain points, sometimes opening in the belly of a carved turn.Maybe you think of this as stiffening? I definitely try to roll them laterally and medially inside the boot as part of tipping.

I do. Fore/aft. Not laterally. I definitely roll them sideways inside the boot.

Maintaining a constant and high amount of dorsiflexion is a focus I've worked on for years. I don't care if professional ski instructor organizations say flex all the joints. I get best results from keeping those ankles closed so the shin stays up against the tongue.

Last season I paid extra attention to when I varied the dorsiflexion angle intentionally, and why. Evidently I had been doing this unconsciously for years, but only in specific situations. I found the variance to be useful in some turns, not so much in others. For example, reaching short radius turns require an opening of the ankle at the top of the turn.

Maintaining constant fore/aft tension in the ankles might be useful only to certain people rather than to everyone on skis. My feet are hypermobile in all planes. So I'm interested in what Gellie has to say.

 

[Tony S]

Technology - Ski

www.lib-tech.com

"Detune your skis for metal, plastic and cement"

Yah. Not my world.

 

[KingGrump]

Don't know about others however I use a serated knife for dicing tomatoes. That way I can keep my (admittedly low) speed up without running too much risk of stabbing fingers.

That is purely due to lack of knife skill.
Don't see too many serrated knives in restaurant settings. Those are usually the domain of the home cook and the uninitiated.
Learn real quick when one have to go through a few bushels of tomato/celery or #100 of onion.
While you are at it, might as well spent $20 and pick up a stainless steel finger guard.



The whole knife/chicken analogy is to show there are usually several factors/action/motion at work concurrently. Rather than the single independent motion/action involved in the conjectures around here. Pure carving for example.
It's all about the subtleties. To most, the result looks so simple. It's actually a complex interplay of multitude of factors/action/motion. A simple example is a skier goes out and buys a pair of bump ski because he/she wants to improve his/her bump skiing. The thinking is " Yeah, I'll great in the bumps once I get on these bump skis. What's his face won gold at the last Olympic on them." Surprise, he/she still sucks in the bumps. Got to change up more than one thing for anything meaningful to occur.

If indeed it is that simple, everyone would be doing it.

Often, these discussions generally goes nowhere and usually devolves along the line of "my God is greater than your God." It's just keyboard talk.

Over the years I have learned there is no one good way to get things done. There are usually many good ways. But there are always many more bad ways than good.

For skiing, I like to concentrate on actually skiing and fun aspect rather than talking about means and methods on the net.
A simple way to clear the keyboard fog is to go out and ski with someone from the forum. You'll be surprise how easy that is.

Like Toby said.

 

[Scruffy]

Over the years I have learned there is no one good way to get things done. There are usually many good ways. But there are always many more bad ways than good.

Ain't that the truth.

As for the discussion, well a discussion forum would be pretty quiet without it. And right now, with what's going on in the world, I appreciate the diversion. The goal is, we all learn stuff from one another. I've learned a lot from reading your posts, I appreciate your knowledge and experience on a broad range of subjects. I hope to ski with you someday.

With these ski discussions, as with most things, I feel you have to learn to separate the wheat from the chaff, and recognize that no one has all the answers, least wise for anyone particular person or scenario.

 

[geepers]

That is purely due to lack of knife skill.
Don't see too many serrated knives in restaurant settings. Those are usually the domain of the home cook and the uninitiated.
Learn real quick when one have to go through a few bushels of tomato/celery or #100 of onion.
While you are at it, might as well spent $20 and pick up a stainless steel finger guard.

View attachment 102547

The whole knife/chicken analogy is to show there are usually several factors/action/motion at work concurrently. Rather than the single independent motion/action involved in the conjectures around here. Pure carving for example.
It's all about the subtleties. To most, the result looks so simple. It's actually a complex interplay of multitude of factors/action/motion. A simple example is a skier goes out and buys a pair of bump ski because he/she wants to improve his/her bump skiing. The thinking is " Yeah, I'll great in the bumps once I get on these bump skis. What's his face won gold at the last Olympic on them." Surprise, he/she still sucks in the bumps. Got to change up more than one thing for anything meaningful to occur.

If indeed it is that simple, everyone would be doing it.

Often, these discussions generally goes nowhere and usually devolves along the line of "my God is greater than your God." It's just keyboard talk.

Over the years I have learned there is no one good way to get things done. There are usually many good ways. But there are always many more bad ways than good.

For skiing, I like to concentrate on actually skiing and fun aspect rather than talking about means and methods on the net.
A simple way to clear the keyboard fog is to go out and ski with someone from the forum. You'll be surprise how easy that is.

Like Toby said.

Well, we need something to do when the covid thread closes for the northern night.

 

[Tony S]

I hope to ski with you someday.

Get the study guide from me before you go.

 

[Mike King]

Got to keep in mind that with these levers mechanical or speed advantage depends on the relative locations of fulcrum, load and effort. It's entirely possible to have no mechanical advantage with a class 2 lever.

That's a special case where the location of the load is coincident with the motion, and that's not the case with the foot and ankle.

 

[Average Joe]

I don't want to get into it, but if it were merely a matter of 'stiffening the feet', why aren't WC'ers skiing 110 to 120 flex boots?

Depends on the discipline. WC SL skiers are on very stiff boots. WC downhillers are on softer boots.
At a presentation from a WC downhiller I learned his boots were the equivalent of a 120 flex (although I'll bet laterally they were quite stiff).

 

[François Pugh]

There is no one size/type fits all. Stiffness and support required depends on individual physiology AND application. Pulling off very high speed high-g turns with high impacts with icy hard surfaces needs more support than your typical casual skiing in soft snow.

 

[JC Ski]

Sorry this gets really long:
TLDR: active dorsiflexion, gastric/soleus activation, and forward leverage are all important and should probably all be used to some extent.

After reading the unfortunate hijacking of the carve thread by one engineer, I came here to see if any progress was made between the two schools of "dorsiflexion vs pushing down with your toes". Turns out the conversation got stuck at what happens to the ski when you have forward pressure.

I'm pretty confident everyone on this thread is a better skier than me so I'm going to try to facilitate more discussion where I can learn from you all.

First, I'll try to define terms I use (even if the definitions aren't perfect or my concepts are wrong, at least you'll know what I'm talking about)-
Position of dorsiflexion: closing the ankle joint
TA activation: attempting to dorsiflex the foot
Calf activation: Soleus and Gastrocnemius attempting to plantar flex the foot

Starting with what we do in our boots:
First thing I want to say is that you can have TA activation or calf activation. Without lifting toes or heels off the ground depending on how your ankle and foot are restricted by your boot as well as where your balance is. Example - in a boot that secured your foot or ankle at any point, you can have calf activation which creates downward pressure without actually lifting your heels. Similarly, if you have some pressure into the cuff of your boots via leverage of your upper body, you can have TA activation at any amount less than the downward pressure you are creating and still have your toes applying downward pressure. Notably a position of dorsiflexion will also create pressure on the cuff of the boot and this can be done with either leverage or TA activation (or a combination of both)

Based on last paragraph, pressure can and maybe should be created on the binding toe piece by toe pressure downward and cuff pressure forward. You create those pressures with some combination of TA activation, calf activation, and leverage (probably less leverage, and the only way to create leverage is TA activation). The mix of which methods of creating pressure in what amount is variable based on ski, anatomy, condition and turn type. This is why skiing takes practice and why instructors are so important, they can see issues within your skiing and give cues that help you try something new to improve. Essentially I don't think there should be two distinct camps here even if some people think one is more important than the others. Maybe it's best to try different combinations and see what works best for you. You'll gain invaluable information that you can use to help guide others to figure it out for themselves.


Forward pressure and skis:
Okay, so I glossed over why I think we want forward pressure. I'll start with where I'm coming from. PSIA level 3 coach got my hips up and forward and it changed my life, open to others opinions but I've probably got some bias.

Can we all agree you don't want your balance behind center (except maybe for some of transition?)

I think you can get by with a range of balance from centered between binding toe and heel, to the center of your binding toe piece. Once you are ahead of the binding toe piece, you are out of balance (also assuming frame of reference changes based on angle right?). Reason for this is binding toe and heel are where your boots act on the skis. Might be a little more complicated with a race plate or system binding. So you can technically balance entirely on the binding toe piece and be perfectly in balance (not creating a torque on the ski?) (Also ignoring camber at the moment because this stuff is complicated, maybe it isn't insignificant for balance so then we bring it back in). Then we would agree that you generally probably want your CoM somewhere between center of binding and binding toe piece.

As soon as you get your CoM ahead of the toe piece of the binding you create an uneven pressure forward which might be called driving the tip or something, who knows. If you are doing that, what happens? I would argue the ski does NOT immediately release the tail, since your weight is still distributed at least somewhat along the length, pushing the tails at least somewhat into the snow even on extremely firm snow. Unless the snow is unable to support the outward pressure of the ski at the tail, it will continue to carve. At extremely high g turns with extremely high edge angle you have less room for being out of balance forward before your tail slips since your margins are much smaller. Maybe you truly have no margin on a perfectly solid surface, but on even pure ice you can make some groove, so I'd argue you just get significantly less margin and have to stay more balanced the more firm the snow is.

Hopefully you all don't tear my inexperienced analysis to pieces, and you take away that it's not black and white, it's a lot more like "inside of a ping pong ball epic powder day shades of grey"


If you do want to tear something apart I'd love to talk more about CoM being between binding center and binding toe piece. I need to think about that more myself anyway

 

[JC Ski]

At least some of that is fundamentally flawed. Might edit again tonight. Binding toe piece acts on ski, ski platform length is long.

I still subscribe to the idea that you have some play in your range of acceptable forward pressure before you lose a carve. And that you should be doing a combination of CoM slightly ahead of center allowing you to more easily be in dorsiflexion while activating TA and calf muscles.

 

[Rod9301]

1. Using the ta is a very inefficient way of getting out of the back seat. Instead, oil your feet back. Same with moving your com forward, better to move your feet back.

2. Your balance should be under the tibia, roughly under the arch. This is the strongest position. And it's approximately over the boot center.

 

[JC Ski]

Using the ta is a very inefficient way of getting out of the back seat. Instead, oil your feet back. Same with moving your com forward, better to move your feet back.

So how do you move your feet back without engaging the TA? In a low friction environment wouldn't engaging the TA pull your feet back relative to your CoM?

Your balance should be under the tibia, roughly under the arch. This is the strongest position. And it's approximately over the boot center.

I don't disagree this is the strongest position. I struggle to fight the feeling that balance slightly forward is better but I clearly don't have a good explanation. I tried above, but after posting realized I made some errors.

When you say balanced over boot center, this would require you to have CoM on the perpendicular line to your skis that comes straight out of center. As you turn down the hill, you would have to maintain this, correct? If you don't move forward (or pull feet back) to continue to be balanced perpendicular to your skis as you move into the fall line, you would end up back seat, right?

 

[Noodler]

My suggestion...

There's a time for theory discussion, but hopefully that doesn't leave you in a place where you're so inside your own head that you lose touch with what really makes the skis perform.

Since this is an old dorsiflexion discussion, just keep in mind that is only one movement in the range of things that can be used to manage your fore/aft position. I think foot pullback via hamstring leg curl is the most effective movement for adjusting my fore/aft. Other folks really like using the close the ankle/open the knee thought to get their hips more forward. It's also not well-understood by most skiers, that counteraction movements also adjust your fore/aft position. It's a great idea to play with these movements on easy slope and feel what works best for your turns.

 

[cantunamunch]

Is this the same JC ski that once had a pair of BROmodels on Epic?

 

[JC Ski]

There's a time for theory discussion, but hopefully that doesn't leave you in a place where you're so inside your own head that you lose touch with what really makes the skis perform.

Love this! I was a golf technique enthusiast prior to getting into skiing, so I'm familiar with a "swing thought" vs "paralysis by analysis" approach.

I'm stuck on a couch for at least another week or two so I'll dive as deep into theory as you all will help take me. I've got my ski thought that I'll use for the first few days off the couch! Hips up and forward was the instructor tip I ended last year with and I'll start this year with. Play around, see how much or how little.

foot pullback via hamstring leg curl is the most effective movement for adjusting my fore/aft. Other folks really like using the close the ankle/open the knee thought to get their hips more forward.

Interesting, so you pull the whole leg back with the hamstring? I'll have to try that. It would also open hips and effectively move you forward, which is maybe what I'm already trying with the hips up and forward.

I also think I'll try skiing with the top two buckets open. Just installed my first booster strap, so hopefully that makes the drill a little more effective than when I've tried it before.

Is this the same JC ski that once had a pair of BROmodels on Epic?

Not sure what bromodels are or what Epic means in this context, so probably not!

 

[Noodler]

@JC Ski - So what movement will you use to get your "hips up and foward"?

The leg curl I described is just like using a leg curl machine in a gym. You're not pulling your entire leg backwards (that will just lock up your hips and kill any chance of using counteraction in your turns). It's just foot pullback via the curl. I think of it as pulling my heel to my butt (without lifting your knee). If you try this you'll notice that the movement also presses the ski tip into the snow.

 

[Rod9301]

So how do you move your feet back without engaging the TA? In a low friction environment wouldn't engaging the TA pull your feet back relative to your CoM?


I don't disagree this is the strongest position. I struggle to fight the feeling that balance slightly forward is better but I clearly don't have a good explanation. I tried above, but after posting realized I made some errors.

When you say balanced over boot center, this would require you to have CoM on the perpendicular line to your skis that comes straight out of center. As you turn down the hill, you would have to maintain this, correct? If you don't move forward (or pull feet back) to continue to be balanced perpendicular to your skis as you move into the fall line, you would end up back seat, right?

Not sure where you're going with this, but clearly you need to keep pulling the get back if you feel that you are in the back seat.

 

[Rod9301]

So how do you move your feet back without engaging the TA? In a low friction environment wouldn't engaging the TA pull your feet back relative to your CoM?


You need to try it instead of arguing.