- Joined
- Jul 5, 2017
- Posts
- 555
Re-reading this a few times helps- and brings up the critical importance of proper footbeds and fore and aft alignment. Not to derail the discussion...warning- thread drift ahead.......when the heel and forefoot are properly supported and aligned, then the sweet spot of fore and aft balance can be achieved. Then the skier can best activate the feet as describe above. And because one has custom footbeds does not mean that the proper assessment and correction was made-sometimes it takes a few times (with mine it took five!).Yes, I see and appreciate the discrepancy you raise. However, if that video were to include dorsiflexion, we would see something different. I am speaking from the standpoint at which anyone reading this can immediately see for themselves what I am saying so we won’t have to rely on finding the “right” words to explain detailed biomechanics. So, for a minute, forget everything else and try the following: First, while standing upright, try rolling out the ankle/navicular on an upright, non-dorsiflexed inside leg (like the diagram below) and notice the ease with you can roll/invert the inside ankle outwards (to the inside of the turn) onto its outside ball and arch and pushing the navicular against the outer shell of the boot as depicted below on the right. Either open or closed chain. Now, try to maintain that ankle inversion that moves your navicular out and start dorsiflexing your ankle. You will see that you can no longer maintain that ankle inversion as your knee moves forward to create ankle dorsiflexion. The navicular moves back in and away from the boot shell. By turn phase two the pinky toe carving is no longer essential as the outside ski takes over and maintaining pressure until it becomes the new inside ski pinky toe edge once again. As a matter of fact, the more plantar flexion we create, the more ankle inversion is possible. You may also see that all diagrams that show inversion/eversion of the ankle are with no dorsiflexion. The reason why you won’t find one is because the two movements are incompatible (mutually exclusive mobility) and why they do not really occur within the same timing/turn phase. The benefit of lack of inversion and eversion during dorsiflexion is the increased lateral stability that we want through the heavily loaded dorsiflexion phase of the turn (phase 2 & 3) and an example of why stability and mobility are often mutually exclusive in the biomechanical context. All our joint’s range of mobility are almost always dependent on the position of the next adjacent joint such as is the kinetic “chain”. We are all familiar how the rotation we get from the hips down and through the legs is in different places when our knees are bent 90 degrees in transition compared to when they are only bent 30-45 degrees in phase 2. We also have more rotational capacity in closed chained or edge locked carving vs open chained or a skidded engagement, something Gellie touches on over a recent post of his on another thread. While an edlocked turn is "closed chain" and the foot lifted off the ground is "open chain", a non edgelocked but skidding ski is semi open/closed chain, a transition of which further complicates the details.
An example, a improper footbed and out of balance setup will force the skier to rely more on cuff pressure (and early dorsiflection, which limits eversion)to move the pressure forward, as opposed to ball of foot pressure. An uncorrected forefoot varus or valgus alters development, which when corrected, may take much concentrated practice to unlearn.
The stance and movements described above in Dobys post are of a skier with either perfectly stacked skeletal structure, or one who has been fortunate to have had proper corrective alignment done. But “perfect” represents a tiny percentage of humans, which leaves the rest of us working a bit harder......
As written above, let your feet talk their way up into the conversation with boot fitters, coaches, instructors. Everyone has personal experiences to add, yes, but everyone’s situation is unique, and there is never one clear “right way” to do this.
