Knee-friendly turning ...

[atkinson]

So the fat ski showdown had a few posters claim that wider boards make your knees hurt. This illustrates a common erroneous concept that we should be using our knees to get our skis on edge.

Biomechanically speaking, this puts our knees at great risk of injury. Our knees and legs are strongest when the hip, knee and second toe are aligning. This movement pattern is for all types of skis, snowboards, sports and even just plain old walking and standing. Tipping your knee in to put the ski on edge stresses the ligaments and cartilage.

The biggest muscle in the body is the gluteus MAXimus and the center of our strongest movements. Use your hips to tip your skis on edge or as I like to say, tip your hip to rip.

 

[Cheese]

Can you elaborate a little more?

Pretty sure this one can be demonstrated in an office chair, right? How are you moving your hips without doing the same with your knees?

 

[SkiDork]

I initiate my turns from my ankles

 

[Cheese]

I initiate my turns from my ankles

I do as well although I learned from Tony Nose (Toe-Knee-Nose).

 

[C-Rex]

It's just like lifting something heavy. Take your legs completely out of the equation. Lift with your back in a jerking, twisting motion.

 

[Highway Star]

Seriously?????

 

[kingdom-tele]

So the fat ski showdown had a few posters claim that wider boards make your knees hurt. This illustrates a common erroneous concept that we should be using our knees to get our skis on edge.

Biomechanically speaking, this puts our knees at great risk of injury. Our knees and legs are strongest when the hip, knee and second toe are aligning. This movement pattern is for all types of skis, snowboards, sports and even just plain old walking and standing. Tipping your knee in to put the ski on edge stresses the ligaments and cartilage.

The biggest muscle in the body is the gluteus MAXimus and the center of our strongest movements. Use your hips to tip your skis on edge or as I like to say, tip your hip to rip.

true.

but, a wider ski creates a longer lever medial/laterally requiring more lateral pelvic shifting which then increases the femoral angles which requires higher contractile force from the adductors/abductors which over reps and time can lead to higher incidence of medial and lateral knee tendinopathy.

 

[Nick]

^ that's what I was gonna say


... :lol:

 

[billski]

How does the length of the ski play into this? Greater leverage or greater stress, or??

 

[wa-loaf]

It's just like lifting something heavy. Take your legs completely out of the equation. Lift with your back in a jerking, twisting motion.

I think you are making a joke here. Cause otherwise that would be really bad advice. :blink:

 

[mister moose]

Atkinson is describing knee angulation vs hip angulation, that is whether or not the knee stays in a direct line (longitudinally, ie parallel to the skis) with the hips and toes. He is correct in that you can ski with just hip angulation (or don't even break at the hip, angulate the whole body, ie lean)

That does not address the increased transverse (across the ski) leverage that must be applied when on a fatter ski on edge, and the lateral force the knee endures to support this. With the larger force required to keep it on edge comes more flex from the boot, more compression of the flesh and foam at the boot cuff, and more angulation required to make up the difference.

All that said, I have not skied the newest rocker all in one ski, and am happy to let them mature in design and go on sale. I'll try them out sometime soon and see for myself, but in the meantime I'm having enough fun on the other 6 pairs of skis I have (each with significantly different areas of performance).

I do notice no one is saying they are better on hardpack, what is being offered up is that they are just as good if you overlook the compromises.

 

[kingdom-tele]

the knee only has 4 motions that are measurable, flex/extend, medial/lateral rotation. any perception of frontal plane angulation(knee insidee or outside of ski) is coming from hip angle. hip angle occurs from the femur moving under the pelvis, the pelvis moving over the femur, or a combo of both which what actually happens in dynamic motion. if your knee "angulates" in or out your ski season is done. biomechanically speaking.

 

[from_the_NEK]

true.

but, a wider ski creates a longer lever medial/laterally requiring more lateral pelvic shifting which then increases the femoral angles which requires higher contractile force from the adductors/abductors which over reps and time can lead to higher incidence of medial and lateral knee tendinopathy.

Can I get that in a diagram? :lol:

 

[mister moose]

the knee only has 4 motions that are measurable, flex/extend, medial/lateral rotation. any perception of frontal plane angulation(knee insidee or outside of ski) is coming from hip angle. hip angle occurs from the femur moving under the pelvis, the pelvis moving over the femur, or a combo of both which what actually happens in dynamic motion. if your knee "angulates" in or out your ski season is done. biomechanically speaking.

I agree with you, but knee angulation, where the knee is no longer in longitudinal line with the feet and hips is how it has been refered to in my experience. Call it femur rotation if you have to, but it is still a lateral movement of the knees (not a lateral flex or hinging of the knees, ouch!)

Picture worth a thousand words dept:

 

[Cheese]

Picture worth a thousand words dept:

Thank you!

 

[Nick]

Damn

 

[kingdom-tele]

I agree with you, but knee angulation, where the knee is no longer in longitudinal line with the feet and hips is how it has been refered to in my experience. Call it femur rotation if you have to, but it is still a lateral movement of the knees (not a lateral flex or hinging of the knees, ouch!)

Picture worth a thousand words dept:

its not lateral movement of the knee. the angle measured is a representation of the bones that make up that joint.

biomechanics can get muddled quickly, language and orientation being major restrictions. no question there is a measurable angle that occurs. to look at that picture from a biomechanical POV the knee angle(valgus of the L leg) is going to be measured by the combo of the femoral adduction/lateral pelvic shift in relation to the knee position, the amount of internal rotation of the femur, the orientation of the foot(again in relationship to the knee position) and the measurement of lateral rotation of the lower leg. the knee is simply the meeting place for the dynamics of the femur and tibia

its the same reason management of IT band issues/knee stability programs are largely focused of hip muscle rebalancing


NEK: I'll draw you a nice picture in the snow when we get some

 

[mister moose]

its not lateral movement of the knee. the angle measured is a representation of the bones that make up that joint.

I'm pretty sure it's my knee, and I'm pretty sure the whole knee moved laterally to edge the ski just a little more. Look at the little yellow arrow:

the knee angle(valgus of the L leg) is going to be measured by the combo of the femoral adduction/lateral pelvic shift in relation to the knee position, the amount of internal rotation of the femur, the orientation of the foot(again in relationship to the knee position) and the measurement of lateral rotation of the lower leg. the knee is simply the meeting place for the dynamics of the femur and tibia

OK, but I still think "lateral movement of the knee" will go a lot further in explaining skiing than the above mouthful.

 

[kingdom-tele]

not trying to change your mind. I enjoy biomechanics, movement, and how our nervous system works. the "mouthful" isn't half of it, you want to tell someone to fix their knee by staring at their knee with no consideration of what is actually occurring is certainly a type of training

 

[from_the_NEK]

I'm pretty sure it's my knee, and I'm pretty sure the whole knee moved laterally to edge the ski just a little more. Look at the little yellow arrow:

OK, but I still think "lateral movement of the knee" will go a lot further in explaining skiing than the above mouthful.

It may be a mouthful, but it explains that the knee isn't moving laterally. It is the rotation of the femur.
Stand up and try to laterally move you knee without rotating you leg. It is impossible (unless you are missing some vital pieces or use a destructive amount of force).

In your picture, the rotation of the femur and hip gives you the visual impression (when covered by snowpants) that the knee is flexing sideways. However, the misleading visual is that your right leg is "pointed" at the camera and looks straight and the "laterally flexed" leg is pointed toward the lower left part of the picture. If you were to change the angle of the picture to look at the leg from that location in bottom left. you would see that the femur, knee, and lower are lined up straight.

The femurs can rotate independently. Additionally the "Hip angulation" you point out for yor right hip is misleading as well. The hips move in two primary planes (up/down and forward/backward). To depict the true hip angulation in your picture you need to connect the two hips in the horizontal plane. Then you see that you left hip is higher than your right hip. This allows the left leg to rotate more effectively.

Edit: keep in mind that the ankle can also rotate a bit (yes, even with a ski boot on) to keep the skis parallel.

Just trying to put this in laymen's terms here.
How am I doing K-T?