by Harald » Thu Apr 06, 2006 1:44 pm
DD if you read the posts and the thread, on knee angulation it will help you with some background about what I mean by skiing with knee drive rather than ankle and foot tipping. I know Greg makes rigid footbeds. I have seen and replaced many footbeds made by Greg that racers bring into my Alignment Shop, (Skunk Works).
Greg and I are competitors, so I?m sure he has nothing good to say about what we do, so you will have to decide for yourself. Look at the systems and try to evaluate the science and measuring differences between our approaches to footbeds and alignment. I am very happy to present our methodology and biomechanical understanding to any skier. After presenting my methodology to the International Congress on Skiing and Science, I?m very relaxed about comparing systems. The Congress is a body of sports scientists from all the skiing nations of the world. My alignment system is the only one ever to be documented and scrutinized by the International Community of doctors, PhD?s, biomechanists and physiologists.
Your skiing demonstrates movements typical of a knee drive type skier. What causes knee drive? First a deliberate technique, which is learned through coaching, can result in knee drive. This could be part of the cause, in other words coaching and movement.
Second, if you have a rigid footbed, your foot tipping is compromised and therefore you have to use femur rotation rather than ankle everson and hip counter to develop angles or grip for a turn. Leg steering is a result and similar to knee drive; any leg steering technique requires the leg to be bend or go into a bending position at the very time skeletal stacking should occur. Bending without a strong counter to control hip rotation, causes pressure loss. Hip rotation does not have to be violent or fast, for it to be detrimental, slow progressive following of the hip causes pressure to be avoided or lost. So when this action or movement happens, you miss the loading and pressuring phase of the turn. If you miss this part of the turn, you don?t achieve ski bending and therefore you don?t have rebound at the exit or release.
Wow, all this because of a footbed? No, I see some underlying hip following in your skiing. I also see (I think I pointed some of this out last time around) your hip squaring up, which reduces hip angulation. In your avatar you begin with hip counter, but you have to check, if it is maintained in the critical phase of the turn.
Ok now, footbed and forefoot varus. There are few ski shop footbeds that measure or address the need for forefoot varus support. We are confident that we have the measuring for this condition down cold. Forefoot varus is a lifted 1st metatarsal, under the big toe knuckle; it can also be a longitudinal twist in the length of the foot that produces a lifted first met. The twist is not necessarily a loose foot condition. Rigid feet also demonstrate forefoot varus.
Diana my partner has extreme pronation and forefoot varus. Many coaches who see her feet comment that a foot like that can?t ski. I can assure you Diana is a great skier and with proper training and opportunity could be a 50 point FIS racer. Many of the changes she has been able to make in her skiing, her technical development, is due to the changes in her boots, footbeds and alignment. I am also amazed that she skis as well as she does given her feet, even on ice.
So what do we do with this condition? We build a footbed that allows the foot to evert, but we control the eversion and we help the foot to stay laterally balanced. For the forefoot condition, we add support under the first met and sometimes up to the first ray. This is determined by a sighting from under the back of the foot to the front. We measure with a goniometer, fancy protractor, how many degrees the forefoot is out of level with the flat part under the heel. The accommodation is built into the front part of the footbed.
The outcome is immediate, for the first time these skiers contact and pressure under a part of the foot that used to drag the knee into rotation. You see, when you have to push hard on the big toe to get pressure and the big toe never contacts the ground, the reaction up the kinetic chain, results in the knee driving over the big toe to get pressure. If you have to do this in every turn, you can imagine how much extra work is involved. It does exaggerate knee drive. Unfortunately the extra work or movement to apply big toe edge pressure doesn?t help ski technique or ski performance.
About fifteen to thirty percent of the population has some degree of forefoot varus. At times it seems higher then three out of ten, but skiers with this condition come to us is spurts.
Just like foot sizes. On a different note, what?s with that? One year coming to our shop we have fat, wide feet that range from size ten to thirteen, the next year we have skiers with narrow, tiny, little feet sized three to eight?
I hope this helps.
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