MA for mountainbum

Re: MA for mountainbum

Postby Max_501 » Tue Feb 07, 2017 7:17 am

mountainbum wrote: FYI I am on 19m icelantics...not the best but they were cheap!


What is the waist width on the skis?
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Re: MA for mountainbum

Postby DougD » Tue Feb 07, 2017 8:24 am

mardale wrote:The deep flexing on that shallow run, while good flexing practice, seems to interfere with the tipping and fore/aft.

Flexing deeply doesnt hinder tipping... it enables it.
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Re: MA for mountainbum

Postby mountainbum » Tue Feb 07, 2017 8:38 am

The skis are a 90mm waist...huge, I know.
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Re: MA for mountainbum

Postby speedcontrol » Wed Feb 08, 2017 9:34 am

Good job mountainbum. Great improvement from the older videos.
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Re: MA for mountainbum

Postby mardale » Thu Feb 09, 2017 6:36 pm

DougD wrote:
mardale wrote:The deep flexing on that shallow run, while good flexing practice, seems to interfere with the tipping and fore/aft.

Flexing deeply doesnt hinder tipping... it enables it.

I think so, indeed, when complemented by a strong pullback, strong enough to allow dorsiflexion, which I don't see here... virtually all new turns start without dorsiflexion from what I see...

So what would be the SMIM? Stronger pull back?
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Re: MA for mountainbum

Postby noobSkier » Fri Feb 10, 2017 9:52 am

Hi mountainbum,

*Disclaimer: Not a PMTS coach*

You are still slightly BTE dominant, in several frames we can observe the formation of a *very* slight wedge. Its obvious that you are working on your tipping, and you are very close...but you need to delay BTE engagement and focus on free-foot tipping.
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Re: MA for mountainbum

Postby DougD » Fri Feb 10, 2017 12:18 pm

mardale wrote:
DougD wrote:
mardale wrote:The deep flexing on that shallow run, while good flexing practice, seems to interfere with the tipping and fore/aft.

Flexing deeply doesnt hinder tipping... it enables it.

I think so, indeed, when complemented by a strong pullback, strong enough to allow dorsiflexion, which I don't see here... virtually all new turns start without dorsiflexion from what I see...

So what would be the SMIM? Stronger pull back?
I can identify several non-PMTS movement patterns in mountainblum's skiing, but which one represents his SMIM I wouldnt want to guess. Max_501 is commenting, and I defer to his greater PMTS knowledge.

Just wanted to point out the technical inaccuracy of that flexing comment, to make sure less experienced PMTS skiers didn't get that wrong idea in their heads.
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Re: MA for mountainbum

Postby speedcontrol » Sat Feb 11, 2017 9:51 pm

mardale wrote:
DougD wrote:
mardale wrote:The deep flexing on that shallow run, while good flexing practice, seems to interfere with the tipping and fore/aft.

Flexing deeply doesnt hinder tipping... it enables it.

I think so, indeed, when complemented by a strong pullback, strong enough to allow dorsiflexion, which I don't see here... virtually all new turns start without dorsiflexion from what I see...

So what would be the SMIM? Stronger pull back?

Of course there is a dorsiflexion , look at the slo mo video.
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Re: MA for mountainbum

Postby mardale » Tue Feb 14, 2017 2:15 pm

Great to know - thank you, Doug.

Flexing enables tipping, but my flexing is nowhere near this level and I thought that this level of deep flexing that we see here, may leave no more room to continue flexing the inside leg and would also make it hard to pull back the inside foot, as the hamstrings may lose some leverage (so I assumed).

Also, I thought that this really deep flexing, putting the hips low and, at speed, if the skier does not have a very strong tipping and inside ski pull back, would lead to the BTE dominance I thought I see there.

I would have recommended going back to and work/re-focusing on pulling back the inside foot and tipping instead of flexing, for a while and then "hold the flex".

I still think I see a lack of dorsiflexion for tipping: as soon as she picks up speed, after the camera, the inside foot seems to slide ahead right after the transfer to the new edges, although both feet are pulled back well just before that.

thank you. I am really curious what the SMIM is now. This is great learning.
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Re: MA for mountainbum

Postby Max_501 » Tue Feb 14, 2017 8:36 pm

mardale wrote:... I thought that this level of deep flexing that we see here, may leave no more room to continue flexing the inside leg and would also make it hard to pull back the inside foot, as the hamstrings may lose some leverage (so I assumed).


A flexible skier can flex the inside leg past 90 degrees.

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Re: MA for mountainbum

Postby DougD » Thu Feb 16, 2017 10:07 am

Max_501 wrote:
mardale wrote:... I thought that this level of deep flexing that we see here, may leave no more room to continue flexing the inside leg and would also make it hard to pull back the inside foot, as the hamstrings may lose some leverage (so I assumed).


A flexible skier can flex the inside leg past 90 degrees.

Image


Further, the hamstrings don't use "leverage" to pull the foot back. They contract... the foot moves back. This is largely independent of hip flexion, which is controlled by muscles at the front of the pelvis, not the back of the thigh.

Try this experiment:

Stand up relaxed but tall on one foot (stance foot) with the free foot just brushing the floor (ie, unflexed). Contract your free leg hamstrings as much as possible. Note how far your foot pulls back toward your butt.

Now flex down as deeply as you can and repeat the above. Unless you have severe ROM issues, your free foot should reach the same position (relative to your butt) as before.

Conclusion: foot pullback (ie, knee flexion) is not limited by stance flexion (ie hip flexion).

Still hoping Max advises on the SMIM!
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Re: MA for mountainbum

Postby mardale » Fri Feb 17, 2017 1:57 am

Doug - lookup the relationship between levers, bones and muscles. Leverage is in fact how muscles rotate bones around a joint and affect the other end... there's no magic.

Also - I think knee flexion and pullback are not the same thing. They must be related, but not the same.

Pulling the foot back requires contraction at the hip (pulling the knee and thigh rearward), hamstrings (bending the knee), and shin (pulling the shin toward the top of the foot).


If we view pull back as a translation movement of the heel across the snow, everything else is a means to an end - so while knee flexion by itself (as when we are flexing the knee while standing) should not be a limiting factor, as you are right, there are other limitations, especially dorsiflexion and boot cuff as we go over 90 degrees of knee flexion.

Either way, if Max deems this a non-issue, then it probably is and my diminishing lack of knowledge shows.
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Re: MA for mountainbum

Postby rwd » Fri Feb 17, 2017 6:51 am

Mardale,
Keep in mind that HH has emphasized that foot pullback should occur ONLY below the knee, using the hamstrings. Pulling the knee back would reverse the hip counter causing hip rotation. Therefore, the position of the free knee in deep flexion does not hinder the ability to pull back the foot below the knee.
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Re: MA for mountainbum

Postby DougD » Fri Feb 17, 2017 11:41 am

Mardale - thanks for the correction re: leverage, and sorry for introducing that distraction.

Regarding how foot pullback is to be accomplished, I believe rwd's post and my suggested experiment are consistent with each other and with HH's teachings. It is an independent flexion of the hamstrings.

Ref: ACBAES1, p. 113, last paragraph; "Contact the hamstring muscles on the back of the stance leg..."
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Re: MA for mountainbum

Postby mardale » Fri Feb 17, 2017 12:44 pm

It is likely that I am confused in that case - the quote was from here, under the "How" heading:

http://www.pmts.org/index.php/read-a-ta ... s-and-hows

While we certainly need to also flex the knee, I assumed (wrongly I see) that at different levels of knee flexion and hip height, the mix of the other movements was different, with the final goal of actually pulling the foot back, as opposed to just flexing the knee. However, the hamstring is also a hip extender, I believe so can also move the knee/thighs back?

Thank you for clarifying it.
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