Skeletal Support

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Skeletal Support

Postby patprof » Wed Jan 18, 2006 7:06 am

I just read this post over on Epic (yes, I still check in there once in awhile). Thought there was some interesting ideas here. Wondered what the PMTS regulars think about this--any conflict with PMTS teachings?
Pat

skeletal support
The conflict is between muscular and skeletal support. While the words seem to invoke the impossible, as all support ultimately calls upon the muscles to do the work, these are two different things.

Muscular support is what most folks think it's about. Big quads, and no fear in using them. Many exercises target the quads, like wall-sits, and folks start thinking that is how they should ski too. This is truly Quad focussed skiing.

Skeletal support is actually a misnomer, but you can see where it comes from. The goal here is to involve ALL the joints in helping you maintain balance, not just a huge reliance on your hips and knees. That means use your ankles, and keep your hips over your feet.

You'll know something has changed when you can relax the hip in the control phase of a turn, push it forwards, and see the support coming from the boot. In effect, you are balancing yourself on top of your feet, as opposed to holding your butt up off the snow while sitting in a pretend chair....

It's much less tiring.

that's the short answer. Hope that helps....Bige
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Wrong direction

Postby Harald » Thu Jan 19, 2006 11:43 am

What you posted sounds like a band aid rather than a solution. If you go to the source of the problem, you can make the changes to irradiate the problem. In the quotes from the post, the problems still exist but band aids are applied to the bleeding femoral artery.

Regardless of what was said in this post, skeletal alignment is very important. Achieving skeletal alignment to deal with skiing forces relieves muscle overuse. Co-contraction is the real answer to muscle interaction around joints. Relaxation of the correct muscle groups, at the right time, in the right place, is the icing on the cake.

Most skiers never experience the real forces of skiing because they are skiing incorrectly. They are shedding forces before they are allowed to build. Most skiers are too active trying to turn the skis. When you turn the ski, you never build forces therefore; you never need skeletal alignment. You do get tired muscles, as you still need to hold the body upright as you fight gravity at the end of the turn. This is what most skiers experience when they say they have fatigue of the quads; they are holding the body with the quads.
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Postby Harald » Thu Jan 19, 2006 11:45 am

Sorry I can't do all that fancy highlightening to make the words look imortant.
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Co-Contraction - the stance foot

Postby John Mason » Thu Jan 19, 2006 9:12 pm

Quads - sure - but - co-contraction - much better.

The use of co-contration to 'lock' the position of the joint which is the body's way of managing balance is totally different then the way most people ski.

To rephrase another way, one of the concepts most foreign to people as they first start learning/experiencing PMTS is the whole concept of the stance ski. They are used to being muscullarly active with that leg. They are used to steering it - up-unweighting - twisting - etc. They are used to most anything except simply standing and balancing on it with co-contracted muscles especially including co-contracted hip-rotators. Yet these are some of the key things to do that unlock the kinetic chain.

In the body there are two ways to basically use your muscles and nervous system. Free and active movement of a muscle and co-contraction and locking a joint. To experience this difference have a friend hold a dollar bill between your thumb and index finger and have them drop it. Because of the nervous system path between your eye and your fingers, your ability to actively squeeze your thumb and index finger and catch the bill will prove impossible. This is just one example of the free and active movement use of your joints and muscles.

Now try co-contration. Lock your elbow joint at 90 degrees and make a fist. Have someone hit your fist down in an attempt to increase the 90 degree locked position of your elbow. Now something very interesting that most people don't even ever consider occurs. Your bicep will fire to keep the elbow joint at the same angle so fast that the joint will hold it's position. Your body will do this even with your eyes shut. The secret is that the nervous system works differently in a co-contracted joint than a free and moveable joint.

So, guess what, this difference is one of the precise reasons PMTS works so well. A co-contracted joint is very strong and can resist movement forces much greater than the same muscle can move a free weight. This is where 'skeletal strength' actually comes from. Not from a free and strong quad muscle but from a co-contrated joint at the knee.

The other fascinating facet to this is a medical concept called pre-synaptic inhibition. When a joint is co-contracted the ability to move either opposing muscle is restricted even with external electrical stimuli until the user of that joint wills to release the co-contration. This is really odd stuff that has now been proven in the laboratory.

To put this another way, when a traditional skier is using their free movement methods of steering their outside leg/foot in a turn they cannot be co-contracted because these are mutually exclusive uses of the joints and muscles. You can either be co-contracted or have free muscle movement.

In PMTS we take advantage of the subtle way the body works and co-contract the stance leg and hip-rotators for strength and balance and use free-muscle control on the opposite free foot to tip and indirectly control what the other leg and hip rotator is doing.

This is also why many an experienced TTS oriented skier make statements that they have never experienced the kinetic chain or the more common comment that they don't believe the kinetic chain exists. They use no co-contraction in their skiing. These people need to, with great dificulty, unlearn virtually all they have learned to be able to ski with a stance leg and free foot.

This is the key why people from the TTS camp do not get it at all.
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Far too advanced for prime time

Postby Harald » Thu Jan 19, 2006 9:23 pm

Thank-you, John, for your professional explanation of intricate concepts that the TTS community can't even begin to comprehend. It would assume that they had some understanding of anatomy and biomechanics.
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Re: Co-Contraction - the stance foot

Postby Max_501 » Thu Jan 19, 2006 9:50 pm

John Mason wrote:In PMTS we take advantage of the subtle way the body works and co-contract the stance leg and hip-rotators for strength and balance and use free-muscle control on the opposite free foot to tip and indirectly control what the other leg and hip rotator is doing.


Dude, awesome post. Could you elaborate to help me understand when the stance leg and hip rotators become co-contracted? What are we doing to cause that?
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it's a simple act of will

Postby John Mason » Fri Jan 20, 2006 1:36 pm

it's a simple act of will

take the elbow example

you can raise or lower your arm at the elbow joint or you can lock that joint and resist all movement.

Now here is an interesting thing you can try (more stupid human tricks). You can lock that elbow joint and at the same time try to move your forearm up and down. This will be very hard. You are experiencing pre-synaptic inhibition.

In the kinetic chain you can do the little doorway test. Stand in a doorway and tip your right foot strong laterally while not co-contracting your hip rotators. You will feel nothing on your other foot. On the other hand if you co-contract your hip rotators and do this if you don't allow the tipping to match but keep your left foot flat you'll almost rip it apart. This is the kinetic chain. If you don't know how to put tension on your hip-rotators just sit - point a leg out - have someone try to twist your foot and resist that twisting with your hip rotators. That way you can figure out what hip-rotator co-contraction feels like.

Rich Messer when he is working with students on the phantom move uses the phrase 'maintain some hip tension'. This co-contracted hip rotator action is what he is referring to.

The knee co-contraction is usally done when people think 'just stand on it'.

The person that is used to actively steering that leg at the hip, on the other hand, (a prolific poster on Epic once answered Si's question on what is the most primary move - named hip rotation as demonstrated as the ability to make bow-ties on flat snow as the most important movement if forced to pick one) actually prevents experiencing the kinetic chain as the doorway self-test will demonstrate.
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Postby patprof » Fri Jan 20, 2006 1:54 pm

Thanks John- If I had heard the term, co-contraction, before I had forgotton it. I hate to admit this, but I didn't understand the term after your first post. You're second one did it for me though.
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Postby jbotti » Fri Jan 20, 2006 1:56 pm

Great work John. It brought me to a new level of understanding.
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Postby 4Slide » Sat Sep 15, 2007 3:09 pm

bump
-J
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Postby Max_501 » Sat Sep 15, 2007 3:48 pm

Excellent timing on the bump. I tried to explain co-contraction over here:

http://forums.epicski.com/showthread.php?t=58687

But as usual a couple of the folks over there decided I don't have it right.
Last edited by Max_501 on Sun Sep 16, 2007 6:58 am, edited 1 time in total.
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Postby 4Slide » Sun Sep 16, 2007 4:44 am

Max_501 wrote:Excellent timing on the bump. I tried to explain co-contraction over here:

http://forums.epicski.com/showthread.php?t=58687

But as usual a couple of the folks over there decided I not have it right.


Interesting as usual.

I think the discussion in this thread here is great in that you are also laying out co-contraction in general terms, and then discussing conscious use of co-contraction as a cue such as "just stand on it" or "maintain some hip tension" as discussed by John Mason. Some weightlifters use a form of conscious co-contraction to help stabilize the load when doing squats; we do it unconsciously in many movements including running and screwing in lightbulbs, but discussing conscious ways to use it to develop movement patterns and accommodate loads in skiing is new to me and great stuff.

You guys may want to consider adding a definition of "stacked" (part of the linked Epic thread) to the PMTS glossary, btw. As used in this forum I think it means optimal use of the skeleton (through co-contracted chain around knee, etc. as discussed by John Mason) to bear forces for a particular point in the turn. For competitive-style bump skiing it means basically feet/knees/shoulders stacked (and is very useful for them in that context) and does not require the same type of co-contraction. Some ski instructors use the bump skiing definition as something to strive for in regular freeskiing, including bizarrely encouraging people to keep their outside hip over thier outside ski; and some ski instructors, such as a trainer locally here, hate the term for promoting golf-cart skiing for that reason. So in general usage it seems to be a term with no real value except to bumpers who know what it means to them.
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Re: it's a simple act of will

Postby Bolter » Sun Sep 16, 2007 10:06 am

John Mason wrote:it's a simple act of will

In the kinetic chain you can do the little doorway test. Stand in a doorway and tip your right foot strong laterally while not co-contracting your hip rotators. You will feel nothing on your other foot. On the other hand if you co-contract your hip rotators and do this if you don't allow the tipping to match but keep your left foot flat you'll almost rip it apart. This is the kinetic chain. If you don't know how to put tension on your hip-rotators just sit - point a leg out - have someone try to twist your foot and resist that twisting with your hip rotators. That way you can figure out what hip-rotator co-contraction feels like.



Great posts John, thank you.
I have a question about the doorway test. Is co-contraction of the hip flexors (to resist twisting as described in a later post) done in both the stance leg and the free foot/leg?
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Postby jclayton » Sun Sep 16, 2007 12:27 pm

John ,
I tried the doorway exercise and holding the hips solid could still tip the free foot . I think I must be doing something wrong according to your explanation . Perhaps a phot would help .

Also if the hips wee both co-contracted wouldn't this impede the increasing use of counter rotation during the turn ? I'm assuming you cant just co-contract one hip at a time .
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Postby Ken » Sun Sep 16, 2007 3:02 pm

"Muscular support is what most folks think it's about. Big quads, and no fear in using them. Many exercises target the quads, like wall-sits, and folks start thinking that is how they should ski too. This is truly Quad focussed skiing."

Essential if you sink at the knees in the lower third of the turn TTS-style when the forces are highest...centrifugal force adds to gravity. This also kills arthritic knees or otherwise damaged knees and shortens the ski day/ski vacation. Sink during the turn, up-unweigh to release, and take lots of anti-inflammatories.


"...keep your hips over your feet"

This is commonly misinterpreted in TTS to mean to keep the hips above the feet laterally--side-to-side. This, of course, prevents any edge angle except that of the slope. Keeping the hips laterally over the feet makes skid-steering easier, tho.
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