Came back after a long nap following late-night noodling only to find that [sniffle]
yet another interesting thread has Taken the Dark Road right back down into the quagmire. Geeze. Sometimes it just feels like ‘Virtual Vandalism’. Oh well… maybe there’s something useful to be found in all the rubble. Kudos to those trying to keep the darkness at bay.
Hmmm. The Ankle Debate looks interesting.
I tend to see Ankles as being quite weak when compared to Hips. Ankles also have a limited range of lateral rotation as compared with Hips. I figure it’s like this…
The 5-degree tipping of a relatively weak ankle (sideways) might be used to laterally move the Pelvis to the side. The overall Mass to be moved is some distance from that Ankle. For instance a 5-degree ankle-tilt would move our Pelvis about 2.8 inches
to the side.
Looking closely we see a weak little Ankle trying to lever a very large Mass using a 32 inch long heavy
pole (that length of leg between the Ankle and the Pelvis). With so little Leverage
for moving that large Mass from so far away the foot and ski
are far more likely to rotate (laterally) when muscle is applied - and obviously that’s what happens.
While skiing, any lateral Ankle articulation depends heavily
on external forces to help it ‘get the job done’ in tipping the upper body. One way or another Ankle Tilt recruits Gravity and/or CF over time
to bring about the intended outcome. Ankle Tipping has no real ‘power’ to move the upper body but does produce small imbalances that take a (relatively) long time to bring about big outcomes. There was an ‘Ankle Power’ thread about this some time ago.
As an alternative we can very quickly move our Pelvis those same 2.8 inches
to the side with powerful Hip articulation. I see three big advantages to using Hip action as a primary
First; Hip movement is quite powerful. It’s easily able to forcibly
maintain whatever ‘tipping angle’ we like. This delivers us a huge degree of lateral-angle stability and resistance to ‘disruptive’ impulses. The Ankle would simply ‘give way’ under stress which the Hips endure easily.
Second; The Hip joint needs to articulate 10-degrees to produce the same 2.8 inches
of sideways Pelvic movement that the Ankle produces with 5-degrees of articulation. While some would proclaim this to be ‘more efficient’ consider that if the Hip joint moves 2-degrees for every 1-degree of Ankle movement (in accomplishing the same outcome) then the Hip joint has a 2-to-1 advantage in delivering angle-accuracy
(suggesting a higher degree of precise body-angle control) and a 2-to-1 advantage in leverage on top of its obviously greater ‘power’.
Third; The Mass that is being moved laterally is much closer to our Hip joints than to our Ankles. This delivers an additional leverage-advantage in moving Pelvic Mass sideways as compared to Ankle joints.
Beginners have much greater control of large muscles than of small muscles. If we didn’t tell them about Ankle use most beginning and intermediate skiers would probably never even know about it - nor care. All Ski-Snobbishness aside, there are advantages to be found in each available mix of segment-tipping joint precedence.
On another Tipping/Rotation front… the very act of ‘tipping our foot with our ankle’ (even in attempted isolation) causes the lower leg to ‘rotate’. Try it while watching your shin and calf. The lower-leg rotates whether the leg is straight or is bent at the knee. This observation is neither here nor there. Just interesting. It does
suggest that a ski-boot liner that restricts lower-leg rotation may actually interfere
I frequently put athletic tape over the tendon in front of my ankle because it ‘rolls’ side-to-side so much that it gets sore. I’ve often wondered at complaints of hair being worn away by ‘shin bang’. Could this be caused instead by many ankle-tippings which in turn force lower-leg rotations inside a tight boot liner…? I also wonder if adding a small piece of thin, slippery material on that tendon might improve Ankle Tipping ease.
Regarding the inescapable presence of torque caused by the tipping of ‘ramped’ feet - I notice that no one chose to respond to the persuasion of my 2x4. Do I need to use a 2x6
on those of you still in denial? ...because a 2x6 would exhibit even more rotation-causing torque making it easier to see.
PS: In the interest of clarity, Torque
is not Rotation
Still, when Torque is present and not ‘Actively’ countered in some way - Rotation Happens. To counter Externally caused Torque
with Internal Torque
a human limb generally has to rotate
at least a bit to get into position before useful anti-rotational tension can exist. Rotating that limb takes an Active Rotational Effort
however scorned, disavowed or denied such effort may be.