CORE CONCEPTS

NOTE to the reader. As at February 19, 2017, this page is currently under revision.


As bipeds, we propel our bodies forward by moving from one fascially tensioned base of support with foot to core sequencing on one foot to another fascially tensioned base of support with foot to core sequencing.

Skiing uses the same basic pattern. In skiing, we need to establish a fascially tensioned base of support with foot to core sequencing on one foot in order to be able to move with precision to another fascially tensioned base of support with foot to core sequencing on another foot. As far back as the 70’s, the famous French ski technician, Patrick Russell, said that the key to effective skiing is to ‘move from ski to ski’. What Russell was really alluding to is the process of alternating single limb support.

Ever since alpine skiing became formally established, it has been known that the best skiers move from the outside ski of one turn to the outside ski of the next turn. Although this may sound simple enough, the key to being able to effectively move from ski to ski (foot to foot) is the ability to establish a fascially tensioned base of support with foot to core sequencing one one foot and then use it to move the body or Centre of Mass to the new outside foot (current uphill ski) of the next turn. Good skiers do this so seamlessly that turns seem to have no beginning or end. The turns just flow together. When viewed in the context of stance and swing phases, the resembles to walking becomes apparent,

How to make skiing as intuitive as walking is what this blog is about. I devoted an entire series of patent to this subject commencing with US Patent No. 5,265,350 and associated international patents on the elements of a minimal ski boot necessary to accommodate the process of establishing a fascially tensioned base of support with foot to core sequencing on one foot and transitioning seamlessly back and forth between bipedal and monopedal stances.

The ability to balance multi-plane torques on the outside leg of a turn is, and continues to be, the secret of the worlds’ best skiers including Toni Sailor, Nancy Greene Raine, Pirmin Zubriggen and, today, Mikaela Shiffrin, Lindsey Vonn and Ted Ligety to name but a few.


A REVIEW OF GAIT CYCLE AND ITS PARAMETERS – Ashutosh Kharb1, Vipin Saini2 , Y.K Jain3, Surender Dhiman4 – https://ijcem.org/papers72011/72011_14.pdf

Dynamic loading of the plantar aponeurosis in walking – Erdemir A1, Hamel AJ, Fauth AR, Piazza SJ, Sharkey NA. – https://www.ncbi.nlm.nih.gov/pubmed/14996881

Active regulation of longitudinal arch compression and recoil during walking and running – Luke A. Kelly, Glen Lichtwark, and Andrew G. Cresswell – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4277100/

The Foots Arch and the Energetics of Human Locomotion – Sarah M. Stearne, Kirsty A. McDonald, Jacqueline A. Alderson, Ian North, Charles E. Oxnard & Jonas Rubenson – http://www.nature.com/articles/srep19403

Shoes alter the spring-like function of the human foot during running – Kelly LA1, Lichtwark GA2, Farris DJ2, Cresswell A2. – J R Soc Interface. 2016 Jun;13(119). pii: 20160174. doi: 10.1098/rsif.2016.0174. – https://www.ncbi.nlm.nih.gov/pubmed/27307512


 

The Science of the Human Lever: Internal Fascial Architecture of the Forefoot with Dr. Emily Splichal – https://www.youtube.com/watch?v=_35cQCoXp9U

 

 

 

 

15 comments

  1. Hello David

    I’m a keen follower of your blog, and have had great success with modifying my boots and linings in line with your ideas. My skiing has improved, and I no longer ski with the excruciating foot pain I had for so many years. Thank you.

    As a consequence of these changes I am keen to retrain my body with certain new (hopefully better) movement patterns. To this end I am interested by the “Roll Over Trainer” shown in “LIGETY’S ROLL OVER EXPLAINED: THE SIMPLE VERSION – PART 3, THE REVOLUTION BEGINS”. do you have a diagram or photos of it shown from the top, front, and side?

    Thanks again 🙂

    1. I am glad if my efforts have helped you to improve your skiing. This is the sole reason and motivation behind my efforts. I also learn a great deal from interactions with my followers.

      I will post soon on the roll over trainer which trains users on engaging the heel-ball of the foot rocker mechanism the rotates the outside ski onto its inside edges and starts the leg rotating internally; into the turn. The trainer also provide a realistic feel of what the rocker mechanism feels like in skiing. Before I can get into the trainer in detail, I need to describe the heel-ball of the foot rocker and how to maximise achilles-forefoot load transfer with stance.

  2. Very thought provoking discussions, some of which I can just about gather. Had a sub/talar dislocation 5 years ago, no fracture, bit of a loose joint at the time from former sprain. Interested if the foot tripod is still not as strong, would that explain why I feel excessive pressure on the soft tissues in the sole of the injured foot? (had to give up using thin race socks as felt numb in the forefoot, slightly thicker sock cured it). With a great physio now past 6 months, strengthening post tib and lower leg generally and now feeling less ground contact pressure on the sole of my foot – in hard office shoes this could be quite uncomfortable and worse in ski boots. On injured foot, doing the 1 legged stand to observe pronation, I can roll onto 1st met, but often get a wobble back the other way and have to concentrate quite hard. Other foot its a nice steady process of pronation and dorsi flex with good stability upto the core. Basically given up skiing now until I am equal on this test, as on the hill problems are amplified and spoil the skiing totally.Thanks for any thoughts.

    1. I am a very big believer in therapies such as fascial release and Gua Sha (http://en.wikipedia.org/wiki/Gua_sha) to re-heal injured tissue. As a child, I was frequently injured because I had no fear. As I grew older, the many injuries I suffered started to affect my mobility. What I learned was that injuries only partially heal. A broken bone or damaged ligament may appear to heal. But the affect on soft tissues usually doesn’t. I had about 70 sessions of Gua Sha as well as chiropractic, physiotherapy, acupuncture and high power laser to release scar tissue that had greatly affected my mobility. It was unbelievable how much easier it was for my wife (who also had Gua Sha) and I to ski after Gua Sha therapy. Fortunately, there are many excellent therapists in Whistler where I live. Here is a link to a fascia therapist in Whistler that may give you some ideas on therapies that might help. It definitely sounds like the muscles of the injured foot and leg are not functioning properly. Keep going until you find the right therapy or therapies. That is what I had to do. I am no longer in constant pain and very mobile.
      http://www.kinesiologywithmajo.com/

      1. Thanks for the link. If I sit and try and do full plantar flex with base of big toe on ground, injured leg calf feels tight and too short. More physio. I was in a semi solid cast for 6 weeks for the dislocation, found out since normal protocol is 2 weeks. Left me with heaps of scar tissue. My advice to anyone else get great physio to look at the injury immediately, EVEN if being dealt with by surgeons – they dont know everything in my experience.

      2. It definitely sounds as if the slippery membrane called the fascia that covers the muscles and allows them to move over each other is congealed. I was kneed in my left shoulder blade during a soccer game when I was 14. In those days, unless there was a broken bone or open wound, no one bothered to even get medical attention. Even if medical attention was obtained, the process was to wait for the injury to get better. Five decades later, I was still suffering from chronic pain that had never gone away despite a lot of physiotherapy. It was not until I found a chiropractor that did Gua Sha that I found relief. It turned out that the fascia on whole sections of my back was glued together in conjunction with a lot of scar tissue. When she first started worked on me the sounds of crunching and popping was intense as the scar tissue was broken up. It took about 70 sessions to free up all my muscles.

  3. David, came across your blog this past week as I was ski boot shopping. Some great insight …

    I’ve read a number of the posts on boot fitting but can you give me a sense of what you define as a good fitting boot?

    Thanks

    1. Wow Jay, that’s a loaded question. Last season I was going to put my wife in new boots. Her present Head boot is more than 12 years old. I estimate that I spent at least 25 hours modifying it to get it to the point where she could ski well. The problem is that the old Lange soft fabric Tricot liners I had substituted for the original head liners that came with the boot were falling apart. I thought it would be easier to start with a new boot. But after I checked out a few different pair, I quickly backtracked and got a new pair of Lange liners from racing stock. If you have any connections, distributors of Lange and Rossignol boots often have a stock of race boots. As far as I can tell, they are the same boot with different colors and logos. If you can get a pair of race stock with the soft fabric liners you might at least have a fighting chance. But you still have your work cut out for you. I hate to sound so pessimistic. But my wife and I ski with about 1/10 the effort of most and with 100 times the enjoyment because of our boots. It still can’t believe that it took me 20 years to to get back to where I was skiing in my leather boots after the new plastic boots reduced me to a beginner. I not only made up lost ground, I went way past where I was in leather boots. The reason I started this blog is to try and help those such as yourself cut to the chase faster. But the boot makers seem to keep outrunning my best efforts.

      1. Hi Dave,

        Following your suggestions I solved the shin bang with my Atomic Hawx 2.0. I had to further expand the width, cut off the elastic webbing and completely modify the tongue as you suggested. I also had to completely remove all the foam from above the top of the foot in the tongue – this solved the nerve pain when I am sitting on the lift with heavy skis. Thank you!

        Your post mentioning race liners is interesting since I am now starting on my wife’s boots. Are the race stock liners all soft fabric without plastic on the tongue? Could you post pictures?

        My problem with my wife’s boots are the size. Her feet are proportioned perfectly for skiing but the problem is they are size 4.5. Her current boot is a 22.5 which is too large, any suggestions for a new boot since I can’t seem to find anything smaller without going to a junior boot?

        Mike

      2. Hi Mike, the following link should get you to a post on 2014/04/08 called BOOT FLEX CAN BE A REAL TURN OFF that shows photos of the liners – boot-flex-can-…-real-turn-off/ ‎

        When I built Langes for racers I had a box of the soft Tricot liners. In recent years, boot makers have added things to liners to keep them from developing creases when the user put the boots on. They are also injecting lasted foam shapes into liners. I could easily remove material from older liners where padding was built on layers. Most liners today are a nightmare to do anything to. I was thinking about fitting myself into new boots this season. But I got ‘cold feet’ (pun intended) after I realized what was involved. I need to spend a few hours in ski shops pulling boots apart to figure out what, if any, options I have. There are quite a few articles on boot fit in the blog. I will compile a list and post it in the next week.

      3. Dave, thanks, I guess! So based on the fact that I might be limited in my ability to ‘change’ my boots (in a Lange RS130) some of your posts / info would indicate that the one thing I can do is get rid of my footbed thus allowing for more movement of the foot, pronation and the like re: Ligety, Shiffrin posts.

        Thanks.

      4. Several followers of my blog have asked whether footbeds should be used. At some point, I will expand on this issue.

        Back in the ’70s, I was a huge proponent of footbeds. There was a well known story at that time about how after getting called to the mountain at midnight for some urgent matter, the head of the Whistler ski patrol turned his car around and went home to get the footbeds I had made for him. He was almost at the mountain when he realized that he had forgotten to put them back in his liners. He flat out stated, “There’s no way I’m going up the hill without MacPhail’s footbeds”. While this seemed to validate my belief in the value of footbeds, I no longer believe in them. I see footbed use as a personal choice. What I did, and what I suggest others do, is start to ask myself and other proponents of footbeds for an explanation based on sound principles of functional anatomy of what exactly it is that footbeds do.

        When I started to look critically at footbeds, I realized that what they seemed to do in a ski shop environment did not translate to the ski hill. Putting something under the arch of the foot in the name of support and then standing on a flat, solid floor with the device under the arch is not the same as having the same device under the arch of the same foot in a ski boot connected to a ski on edge. In this situation, the only aspect of the ski equipment/foot system that is supported is a narrow band along the inside edge of the ski. This situation is like a house with a foundation hanging over a cliff with only part of the foundation supported. If there is no support for the boot in which the footbed is installed, the footbed cannot possibly support the foot as whole. Without support under the outside foot of a turn, the ski and foot will rotate away from the turn or invert. Pronation involves eversion (rotating into the turn). If the load impressed by COM on the outside foot of a skier is causing the foot to invert, then pronation is impossible. So why are footbeds being promoted as a means to stop something that cannot occur? Does mean that footbeds have no value? Not necessarily. If someone has a serious foot pathology and they really want to ski, then reasonable means to accommodate them should be considered even if they will never become great skiers. When I worked on ski boots, I was able to accommodate several people who had reached the point where they could no longer enjoy doing something they love – skiing.

    2. In response to your question of boot fit, my US Patent No. 5,265,350 was for the most part a specification of the required clearances of the boot structures for aspects of the foot and leg as identified in our on hill studies of the mechanics and biomechanics of skiing using an instrumented device that replaced the ski boot called The Birdcage. This device allowed the study of skier balance and the mechanics of ski control and especially the effects of interfering with the joint articulations associated with these processes. The patent describes counters for discrete aspects of the foot and leg. But the counters are for the most part foot/leg to boot clearance specifications that can be applied to boot fitting by anyone who reads the patent. I am planning to delete all the legalese and re-organise the content so it will be easier to apply. There is a link to this and my other patents under HOME> About Me> Disclosure under the opening page header.

  4. Timing and direction of movements in motion. Efficient skiers start moving to the new foot early and progressively as they direct their CM along the line where they are going and going “next” – foragonal!

    1. Exactly. Many mistake the early move to the inside ski as the skier finishing their turn on the inside ski. The reality is that there is only a turn and a transition when skiers make this early move. The ski is moving CoM forward so that as the ski flattens on the snow during the edge change C0M moves to the ball of the foot and the skier simultaneously applies rotational force of the leg with the hip rotators. This cannot occur if the boot structures are impeding the 3 dimensional movements of the elements of the foot.

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