setup tweaking: locking rear knee?

[pow4ever]

locking knee while riding is bad.  stay low, bent knee and relax.
It also mess up your knee when the dreaded thud/thud/thud blown carve.

Likely it's bad technique/habit.  I wonder if there are general rule of thumbs on tweaking the binding setup to deal with this?

interesting part is that my rear knee seems to complain more when i was riding/carving well.
Maybe too much extension?  

\My front knee seems to be doing good.
My back knee is FUBAR.
my setup:  no cant.  F2 big block pure toe lift(front foot) and pure heel lift (back foot)

I went from 60/55 angle to 60/60 and it seems to feel better.
i am suspicious of the heel lift?

Deelux boot/track 700.  maybe i need stiffer spring and more forward lean (or maybe less)?

Part of the decade long dial it in progression.

[SunSurfer]

Rear ankle and knee both need to bend to allow you to move your centre of mass up and down to absorb the bumps in less than perfect groomed snow.

A relatively stiff rear boot spring system will make more of that movement happen at the knee and allow less movement of the ankle. That would seem to be more likely to upset an already damaged knee joint.

The angles you are riding should allow you to carve your edges by gently leaning onto the left or right side of the soles of your feet, and saving your knee bend for bump absorption.

Those same angles should make for your current lift/cant setup to need no adjustment. If you try anything try turning your front foot to 65. In the video I shot of you at Buttermilk in 2019 you could do with a little more turn of your body towards the nose, especially on your heelside turns. I've still got the original footage archived away.

Edited December 27, 2021 by SunSurfer

[Carvin' Marvin]

I'm not entirely sure what you're asking, but yeah the rear knee shouldn't be locked in any position, especially extension, for any reason while carving unless I'm doing it wrong.  Seems like a fitness or strength issue.  Build the supporting muscles and stretch to take strain off the cartilage and ligaments.

[pow4ever]

Thank you Alan:  
re increase front angle.  I was thinking/feeling about that as well.
At some point higher angle we start to hit diminishing return and lose leverage?
Will play around with it a bit and leave the spring alone for now (one change at a time).

Thank you CM!
That make sense; even in full extension knee should never be locked. 
Strength and stretching is just what the doctor ordered.
let me rephrase it -  while it's still fresh in memory
i typically ride pretty up right but mostly loose/relax and with knee bends.
In the East coast/early season we get tons of ice patches (jokes goes if you can't see fishes; it's not ice it's just New England hard pack).
In mid carve; hitting ice patch (going low) I tend to bolt upright /hyper extend/lock the back knee to catch myself from falling.
That bad habit i need to worked on (i am aware of it now so i am paying attention to it).
When I am "up righting" with both knees to catch/balance myself; but seems the back knee is taking the majority of the force.
(granted the back knee already weak/damage).  Just wondering if there are setup tweaking can be done to promote/help with the load distribution.

[Jonny]

Gosh - If I were to lock out my back knee I'd have to be WAY out over the front of the board. So, as a first step I'd say you might want to feel more centered over the sidecut. In any case I'd much rather take a fall or two than ever lock out a knee. Easier to heal a bruised hip than a blown femur.

If your back knee is really compromised for strength (here's where I put on my flameproof suit) then you might experiment with a more old-school late '80s/early '90s setup - bindings closer together, slight inward canting, and tuck your back knee right into the crook of your front knee. It's most definitely out of fashion, and for it to work you need good flexibility at the waist so that you're angulating not banking into every turn, but it worked then and would work now too.

[Corey]

Like all internet diagnoses, this is worth exactly what you paid for it: 

Where are your hips pointing? Towards the toeside edge? In line with your feet? Towards the nose? 

One of the best tips I got was rotating my hips towards the nose*, and they end up in-line with my feet and shoulders. Then a heelside becomes more about a lateral movement, like skiing. This pushes your rear knee forward and sets up a very athletic stance with less internal stresses between your joints. 

* Males, pee on the nose of the board

If you can't do this, play with your bindings/boots/lift/cant until you can. 

[SunSurfer]

8 hours ago, pow4ever said:

At some point higher angle we start to hit diminishing return and lose leverage?

In the East coast/early season we get tons of ice patches (jokes goes if you can't see fishes; it's not ice it's just New England hard pack).
In mid carve; hitting ice patch (going low) I tend to bolt upright /hyper extend/lock the back knee to catch myself from falling.
That bad habit i need to worked on (i am aware of it now so i am paying attention to it).
When I am "up righting" with both knees to catch/balance myself; but seems the back knee is taking the majority of the force.
(granted the back knee already weak/damage).

Re leverage: It does get harder to put the board on edge the further the little toe side of your boot is from the edge. Unlikely to be an issue at 65 degrees unless you have tiny feet for your height, or you are riding a board with a wider waist. Even then, some lateral binding bias allows effective board tilt onto the edge. 

Corey and I are both saying roughly the same thing in terms of torso and head position, and the board tilt technique that follows on from that (ride like a skier). That will make it easier for BOTH your knees to flex together to absorb bumps and to extend together to maintain centre of mass position when edge grip lessens on the icy patches.

Consciously using both legs will help you stay centred over your board, and reduce the loading on your rear knee.

[pow4ever]

Thank you Johnny!
Now the memory start to fade:
I don't believed i fully locked my back knee (that would be bad).  The feeling/side, after effect of hard carving feels that way.  Now if I just standing around; locking my knees feel tight/wobbly/not stable.
It's funny that you mentioned that jam the back knee toward the direction where i wanted to go seems to help with the body position.

Thank you Alan:  i will play around with the angle next time i am on the slope.  Need sometime to recover.
I was riding a 23cm waist board (due to the variable condition) so riding 60 degree feels it take more effort but do-able.  Back it down to ~45 feels pretty neutral.  on my regular board ~20cm 65 degree should be fine.
Finding that Golidlock/optimized setup is the plan.  I am finally able to feel the subtleties when i tweak.

Thank you Corey:  Momma say if i keep play with that thing i will go blind