Update and editing of previous fore/aft and boot flex post.

[h.harb]

http://harbskisysems.blogspot.com

The total article about boot biomechanics is on my Blog.
http://harbskisysems.blogspot.com

Notice how with my ski boot behind my hips, I can still get a strong forward angle on my boot from my shin. I weigh 145 pounds and this is a Head RD World Cup 150 flex boot. Proving my point, you want a strong boot to be able to send pressure to the front of the ski.

Perspective on this photo, it is on a steep slope, probably 40 degrees plus, it is icy with a thin frozen sugar dusting surface. You can see the brushed carve tracks behind my skis.

[WNYSkier]

Harald,
Thank you.

To everyone reading,
Read Harald's post, then read it again. Think about it, then read it a third time.There is so much information about achieving and maintaining fore/aft balance in this post. For many skiers, especially those who believe they are already skiing well, this post is a game changer.

Cheers,
Mark

[geoffda]

Awesome stuff. What's the solution for skiers with longer femurs? That is the situation I'm in and in the back of my mind, I continue to wonder if there isn't something I need to be doing with my boot setup to help compensate for this...

[h.harb]

Lifting the heel on the outside of the boot and increasing the forward lean with spoilers in the back of the liner. That is the usual, if not cure, definite improvement. But I think you tried our lifted binding ski set up. It's worth trying it on your own skis and boots. I'd try at least 3mm lift.

[skifastDDS]

Very interesting post, thanks Harald. I have very long femurs (6'3) but I find spoilers to be detrimental to my skiing; they inhibit my ability to release turns. I have a ~3mm lift under the toes of the bindings on my race skis to decrease delta.

[geoffda]

Very interesting post, thanks Harald. I have very long femurs (6'3) but I find spoilers to be detrimental to my skiing; they inhibit my ability to release turns. I have a ~3mm lift under the toes of the bindings on my race skis to decrease delta.

Just to be clear, by "longer femurs" what we're really talking about is femurs that are longer than the tibia/fibia. It isn't the overall length of the femur that is an issue, it is the relative difference in length versus the lower leg. When the femur is longer than the tib/fib, the hips are pre-disposed to move behind the feels when the knee is flexed. When the tib/fib is as long or longer than the femur, the biomechanics are more favorable to keeping the hips in front of the heels.

Harald, thanks for the answer. I didn't like the heel lift at the time, but my skiing is completely different now. I'll have to play around with that next season.

[h.harb]

Geoff is absolutely on track, by "long femur" we are talking about a relationship, with your own tibial length, (a short upper body relative to leg length also influences this) it is not a person to person comparison or an individual's femur length. For JB raising the heels and adding spoilers made such a huge difference, you can see it in the ability to skate on skis across the flats.

[Max_501]

a short upper body relative to leg length also influences this

What is the fix for the long legs/short torso combo?

[h.harb]

Figuring how to keep the hips heading forward and the feet pulled back.

[Max_501]

Direct link to HH's blog post:

Addressing boot flex for ski racing and advanced skiing

[HighAngles]

Wow. I missed this over the Summer. This is one of the best blog posts HH has put up. I think I could read this a hundred times and keep coming away with more and more understanding. I think linking back to this post will become my automatic response to anyone who questions stiff boots again.

[Kiwi]

When I was in 110 flex boots I couldn't understand the benefit of stiff boot. Now I am in 140 flex head raptor RS boots are can't believed I actually liked the 110 flex. I would go stiffer but getting a good fit 150 is not that easy for me.

[h.harb]

Kiwi, there isn't much difference between a 140 and 150. You are actually skiing 150 flex or stiffer on cold days with your boots. The only real benefit to going stiffer is for summer training or on warm days. Notice how the WC skiers bury their boots in snow at the race start, stiffer is better for them on warm days.

Once you are well balanced in a boot stiffness shouldn't really matter, you are using the front and back of the boot to help you stay where you want. Just like in the article I wrote flexing the boot isn't the goal, it actually reduces pressure to the ski and it makes the effort take longer. For growing, young racers the boot needs to be strong enough to transfer energy without bending uselessly, just like for a mature racers.