When to pull back feet in bumps

[jack97]

Show me a case where bringing the hip forward will limit the absorption range.

 

[Mike King]

Well lean against the front of the boot and see how far you can flex. Next, lean against the back of the boot and see how far you can flex. There is far more range of motion on the back. That might be why, in part, world cup slalom racers look like they are aft at edge change.

The boot limits ankle flexion. At the limit of ankle dorsiflexion, to have the hip forward the flexion in the knee must be limited. So, to maximize absorption, the hip has to move behind the feet -- the opposite of bringing the hip forward.

Mike

 

[mdf]

Rich, one big thing to change in your bump skiing is to get away from the extension turns where you extend your body upward to lighten your skis and turn. This does not permit you to absorb the impact of the bump.

I used to have that problem. It led to what I called "double pumping" -- one up down cycle for absorption and a seond one for an extension turn. Messes up the timing, as you might imagine.

 

[LiquidFeet]

Well lean against the front of the boot and see how far you can flex. Next, lean against the back of the boot and see how far you can flex. There is far more range of motion on the back. ....
At the limit of ankle dorsiflexion, to have the hip forward the flexion in the knee must be limited. So, to maximize absorption, the hip has to move behind the feet -- the opposite of bringing the hip forward.
Mike

If you dorsiflex as far forward as possible, that has no effect on available knee flexion or hip flexion. Both of those are still fully available when the ankle is as closed as you can make it go.

Compare two stances:
case #1: ankles are closed tightly; shins are tilted forward, pressed into boot tongues, plus knees are closed far enough to get thighs horizontal.
case #2: ankles are open so shins are vertical, plus knees are closed far enough to get thighs horizontal.

Which one has the hips farther back? It's case #2.

I'm trying, but I just can't wrap my head around why you think strong dorsiflexion limits knee and hip flexion.
Or that strong dorsiflexion keeps the hips farther back than keeping the ankles more open.
I'm guessing that I've misunderstood your words....

 

[Rod9301]

You can't hit the front side of the bump with your ankles closed.
The hips have to be behind.
After or when you crest, pull feet back to close the ankle

 

[Mike King]

Dorsiflex as far forward as possible.
That has nothing to do with available knee flexion or hip flexion, both of which are still fully available
when the ankle is as closed as you can make it go.

Compare two stances:
case #1: ankles are closed tightly; shins are tilted forward, pressed into boot tongues, plus knees are closed far enough to get thighs horizontal.
case #2: ankles are open so shins are vertical, plus knees are closed far enough to get thighs horizontal.

Which one has the hips farther back? It's case #2.

The question wasn't which one is further back, but which one has the greatest vertical range of motion? Having the ankle in a more open position (dorsiflexion) allows the available range of motion in the knee to bring the CoM closer to the snow than if the ankle is more closed (plantar flexed).

I'm trying, but I just can't wrap my head around why you think strong dorsiflexion limits knee and hip flexion.
Or that strong dorsiflexion keeps the hips farther back than keeping the ankles more open.
I'm guessing that I've misunderstood your words....

My point here was that you can't more the hip forward and effectively flex to the limits of your range of motion. Flexing is going to require the knee to close, and that will move the hips back.

I guess the rest of the point is that using the full range of vertical motion in the bumps is going to introduce fore/aft management. That is, going to the "shortest" position is most likely going to move you aft on the ski, and as you extend on the back side of the bump, you are going to have to move forward to maintain balance.

Mike

 

[LiquidFeet]

Just for clarity:

Dorsiflexion is "closing" the ankle.
--When in ski boots, dorsiflexing brings the shin into
contact with the boot tongue, and tilts the shin forward.
Dorsiflexion brings the knee forward.

Plantarflexion is "opening" the ankle.
--When in ski boots, plantarflexing makes the shin upright,
and if overdone tilts the shin back. This presses the calf
backwards against the back of the boot cuff.
The knee moves back when the ankle is opened.

Closing and opening the ankle, all by itself, moves the whole body fore-aft.
(Sorry about the size of this image; I can't figure out how to make it smaller...)

 

[jack97]

You can't hit the front side of the bump with your ankles closed.
The hips have to be behind.
After or when you crest, pull feet back to close the ankle

I will repeat again.... "moving the hip forward allows more absorption range without the upper body folding forward". When you're at max absorption the hip should be behind however having it forward during a tall position to begin with allows for the hip to drop down without folding the upper body, the latter would result in absorbing the bump with the small of the back.

And I would content that you can hit the side of the bump with the ankle closed and it is desirable to do so.

 

[jack97]

The question wasn't which one is further back, but which one has the greatest vertical range of motion? Having the ankle in a more open position (dorsiflexion) allows the available range of motion in the knee to bring the CoM closer to the snow than if the ankle is more closed (plantar flexed).



My point here was that you can't more the hip forward and effectively flex to the limits of your range of motion. Flexing is going to require the knee to close, and that will move the hips back.

I guess the rest of the point is that using the full range of vertical motion in the bumps is going to introduce fore/aft management. That is, going to the "shortest" position is most likely going to move you aft on the ski, and as you extend on the back side of the bump, you are going to have to move forward to maintain balance.

Mike

You may have miss the point of my replies or I may not have clarified, the hip forward is a positioning thing during the tall stance. Once there, one can drop the hip for max absorption without folding the upper body forward. Look how he clears and pushes the hip out over the bump and then drops them during his absorption..... all this without using his back to absorb the moguls.

 

[jack97]

Dorsiflex as far forward as possible.
That has nothing to do with available knee flexion or hip flexion, both of which are still fully available
when the ankle is as closed as you can make it go.

Exactly!...... Just a historical note, when the Finnish skiers were dominating the WC in moguls (meaning not alpine), they put more focus on flexing the ankles as they approach the face of the bump, to call carve or "micro carve" the front side. The benefits of this speed control in lowering the COM and load the ski both to absorb the speed. The other is to control where on the side to release that turn and to get ready for the next turn.

Below is a drill where they are making turns in the low position to emulate the front side carve. In order to do this, they have to close those ankles and get the arms forward just to get most of the weight on center to control the turn, Fearing does a version of this in his vid where he does flex his ankles more but he most likely is using older boots with more cuff lean.

 

[jack97]

I usually don't post vids of "non professional" skiers to make my point because it may not have been their intent for instructional use. That said, below is a great vid of a bumper using the front side carve to control his descent.

 

[RichGuo]

Finally I achieved getting down black mogul course successfully, it does not looks graceful, but it's my first day getting down this black mogul course from top to bottom.


the vid below shows how my failure was and I always experienced like that.

 

[jack97]

Finally I achieved getting down black mogul course successfully, it does not looks graceful, but it's my first day getting down this black mogul course from top to bottom.

the vid below shows how my failure was and I always experienced like that.

The biggest difference, the first vid, you kept the skis under center for the most part. Second vid, even at the start of the run, you approach the bumps more on the back seat and lost it when you went to far into the back. As for grace, by doing more tail lifts, the knees will come closer as you develop dominance on the down hill ski and develop more into a narrow stance. IMO, the up move after each bump is a result trying to get in a better position for the next bump.... nothing wrong with that, sometimes you have to do that. The problem is when that's your only move to transition the turn. Skiing in a narrow stance with legs close together allows the hip to shift the weight quicker from leg to leg, that quickness will you ready for the next turn sooner.

It looks like you took a different line as well, the snow contrast was hard to see. Again. nothing wrong with that as long as you understand why you can ski one line better than another.

 

[François Pugh]

Finally I achieved getting down black mogul course successfully, it does not looks graceful, but it's my first day getting down this black mogul course from top to bottom.


the vid below shows how my failure was and I always experienced like that.

Good progress, but you still need a lot of work in extension absorption. Notice how the white stripe in your jacket is moving up and down. Notice how the old bumper in the video Jack posted moves his feet into the holes and lifts them over the bumps instead. Keep practising.

 

[LiquidFeet]

@RichGuo, that first vid is SO much better than the second one. Congratulations!
What did you consciously do differently to get that run to work better?
(You probably did other stuff unconsciously, too.)

 

[RichGuo]

@RichGuo, that first vid is SO much better than the second one. Congratulations!
What did you consciously do differently to get that run to work better?
(You probably did other stuff unconsciously, too.)

I paid more attention on getting forward and flexion as Jack and all other great mentors mentioned.
Most important is mental image changed, when I skied on deep snow mogul, I see only the path which trough goes,pointed skis more direct to fall line, I just had hard time to picture how I could pivot more letting my skis cross more in such narrow deep trough. and after first 2 bumps, the speed picked up and I lose time doing flexion and pull back feet.

latest run, I committed to control first 2 bumps by pivot more and use less edge angle, this had double wins, first I win time to do flexion(absorption), second I see the path on front side with clear mind where to go.

Actually I practiced more pivot slip more on steep pitch recently, it give me impressions that low edge angle actually control speed more effective than carving.

Thanks for your tips on pivot slip!

 

[LiquidFeet]

....
Actually I practiced more pivot slip more on steep pitch recently, it give me impressions that low edge angle actually control speed more effective than carving.
....

Yes!

 

[James]

it give me impressions that low edge angle actually control speed more effective than carving.

How carving got associated with speed control is beyond me. But you see this all the time here. Prove it to yourself by doing railroad tracks on a blue trail. Any turn shape you want. Pretty soon you'll have to be Hirscher to pull it off.
At Jackson Hole, maybe use a green.

Carving {is to} speed control
............as............
Ferrari {is to} slow

 

[RichGuo]

How carving got associated with speed control is beyond me. But you see this all the time here. Prove it to yourself by doing railroad tracks on a blue trail. Any turn shape you want. Pretty soon you'll have to be Hirscher to pull it off.
At Jackson Hole, maybe use a green.

Carving {is to} speed control
............as............
Ferrari {is to} slow

To me , carving railroad like take bullet train.

 

[PTskier]

I had some mogul coaching from a former freestyle competitor. Not competition coaching, just duffer coaching. His points:
--Always keep your chest pointed down the hill. You are rotating your chest around to match your skis.
--Reach way down the hill with your outside pole. This gives one more angulation for better edging and speed control, and gets one ready for a quick turn.
--Be set up & ready to make the next turn before your skis are in the fall line. You can then turn on any bump that looks good to you.
--Look two or three bumps ahead. Just look at the one you're on with your peripheral vision. This way you can plan your course before you slam into it.

You are still extending to lighten your skis to turn. We know, this is a deeply ingrained habit. Changing to make absorption (retraction) turns as I posted in the videos in posting #78 is a total change of movement. If you learn that through lots of practice, you'll like the result.