Fore/aft alignment when boot shopping

[James]

I thought spoilers were more to take up a little room for those with thinner calfs. Have others noticed a significant difference in helping with back seat driving with spoilers?

You can significantly change forward lean with spoilers that go from a heavy 1/8 inch to 1/2 inch. Don’t know about this backseat driving thing. I doubt that could be determined by words.

 

[Noodler]

I thought spoilers were more to take up a little room for those with thinner calfs. Have others noticed a significant difference in helping with back seat driving with spoilers?

The effect of a rear spoiler on the cuff completely depends on the individual skier. For some, it's exactly what they need and for others it will take them in the completely wrong direction. No harm in experimenting with them and without them, but if you do, you really can't just go by "feel", it's best to have video of the testing and a trained eye to review the results and assist with the final alignment determination.

 

[Chickenmonkey]

I thought spoilers were more to take up a little room for those with thinner calfs. Have others noticed a significant difference in helping with back seat driving with spoilers?

Yes, funny story.

i had put some cork floor protectors (what you put under a sofa leg) between my liners and boot shells a while ago. Phil was setting me up to demo some skis and I showed him my handy work. We sent straight to his workbench and pulled out some spoilers and gave them to me. Thanks Phil!

It has helped me with fore/aft balance quite a bit. My quads do get more tired though…gotta work on that.

 

[Jerez]

I had an instructor take the spoilers OUT of Nordica Dobermanns (many) years ago to correct being too far back.... So @Noodler is right. trial and error. Thankfully it is an easy thing to do.

 

[otto]

The posts from Chickenmonkey and Jerez say it all. Two different humans, 2 different on hill tests, 2 different FL results. So much for the one size fits all solution.

 

[Average Joe]

Do you recommend skiing a boot before having it canted?

Yes.
Having a bootfitter permanently alter your boot soles based upon a measurement and observation before you’ve skied, and without on snow input, is a crapshoot.
Because it is common practice does not always mean it’s a good idea.

 

[cem]

so many clients call me up wanting to buy a boot and do a full alignment at the same time, my normal approach is lets sort the boot the footbed and the basic set up and see roughly how far you are out before we sign you up for the whole thing (it saves my time and their money) , so many people have a much better set up if they are simply in the correct size and shape of boot with the correct level of support under the foot, many of the alignment problems they have been suffering are from a boot a size or two too big or with too much volume and a poorly constructed footbed. slowly slowly catchy monkey

 

[Duplo]

What is the correct method when measuring ankle dorsiflexion so that the correct forward lean/boot board ramp angle can be determined.

Do you measure with the foot off the flow and knee flexed, then pull up with the foot and measure that angle.

Or do you do it with your foot on the floor and flex your tibia forward keeping the heel down until you run out of range?

Also, which landmarks do you measure from? Sole of foot is simple if your foot is on the floor. But do you measure front of tibia, or back of calf, or a lone from mid knee joint to ankle bones?

Thanks

 

[otto]

What is the correct method when measuring ankle dorsiflexion so that the correct forward lean/boot board ramp angle can be determined.

Do you measure with the foot off the flow and knee flexed, then pull up with the foot and measure that angle.

Or do you do it with your foot on the floor and flex your tibia forward keeping the heel down until you run out of range?

Also, which landmarks do you measure from? Sole of foot is simple if your foot is on the floor. But do you measure front of tibia, or back of calf, or a lone from mid knee joint to ankle bones?

Thanks

Hello Duplo,

I remember you from a thread on adapting an Atomic releasable cuff boot for a heel spur. What is an interesting possibility is that there is a direct correlation to heel pain in ski boots relative to the range of motion or lack thereof in the ankle joint. Low flex ankles will have a tendency to lever the heel off the boot floor therefore "bumping" into the top edge towards the outside of the calcaneous or heel bone. Hyper mobile ankle joints can also bump hard into the heel bones on the back of the shell as the hypermobile ankle can allow for the foot to collapse in the midfoot which could force the heel bone rearward in the deepest flex position of the boot.

From the internet, I cannot assess either the range of motion of your ankle joint or what the situation is that caused heel pain in that boot and no heel pain in other boots that you owned.

Assessing the range of motion in the ankle joint has to be done in a manner that isolates the basic "saddle" joint of the ankle. To isolate the ankle joint the first thing to do is take the body weight off the joint and position the foot/lower leg in a neutral position where a repeatable read can be taken. You can do it low tech by simply using your eyes to see how big a gap between the floor and the 5th metatarsal head you can create. Me personally, I use my pinky finger and or 4th or third finger as my measuring tool for ankle ROM. You could also use a digital angle meter if you are a numbers kinda guy.

Basic premise... Seated position in a chair or bench that will have the femur parallel to the floor when the feet are flat on the floor and the lower leg comes off the feet at 90 degrees, the femur should create a 90 degree angle to the lower leg, and the back should be 90 degrees to the femur at the hips, meaning that your body mass is mainly supported through your ass sitting on the bench or chair and your feet are semi weighted on the floor. Your thighs, shins, and feet should all be parallel and approx hip width apart so there are no diverging or converging angles of right or left side. With out any directional torque of the foot, the fitter would hold your heel bone to the floor as you lift your met heads as high as you can in a direct line towards the knee. In this position you would either measure ( for me with my pinky finger ) directly underneath the 5th met head to see how big or small the range is. Few or no fingers is tight, 2 fingers is normal, and greater than 2 is headed towards hyper.

So normal ROM for humans is 10 to 18 degrees for dorsiflexion. Below 10 degrees is tight and over 18 degrees is hyper. To find the matching net forward lean for the set-up of the skier that you are looking at is simple math of subtracting the ramp angle of the bootboard from the forward lean angle of the boot spoiler. So if the skier has an ankle that is 1 pinky finger that means that their number is going to be below the 10 degrees of a normal ROM ankle. If the boot spoiler is 17 degrees of FL, and the bootboard stock out of the box is 4 degrees, you would subtract the bootboard number, from the FL number and in this example the net number is 13 degrees. The ankle in this example is only one finger, so for this example the ankle has about 8 degrees ROM. How do we get the net FL number to match the action of the ankle joint? We get the net forward lean number to match the ROM of the ankle. So for this boot we cold raise the heel height to make the bootboard ramp angle to be higher ( lets say that we raise it enough to make the ramp angle 7 degrees), and then take off the FL shim that was screw riveted to the spoiler. This will make the boot FL go to 15 degrees. Now subtract 7 from 15 and the net FL angle of the boot is now 8 degrees... Bingo!!! A love match between the ankles ROM and the boot that the ankle is going into.

 

[James]

Hey @otto , what was your assesment of Daviv McPhail’s bootboard angle determination?
He was starting there, determining it by activation of the stretch reflex. I could never quite understand it. He ended up with very low angles like 2.3 degrees I think. Maybe 3.2.

 

[Duplo]

Hello Duplo,

I remember you from a thread on adapting an Atomic releasable cuff boot for a heel spur. What is an interesting possibility is that there is a direct correlation to heel pain in ski boots relative to the range of motion or lack thereof in the ankle joint. Low flex ankles will have a tendency to lever the heel off the boot floor therefore "bumping" into the top edge towards the outside of the calcaneous or heel bone. Hyper mobile ankle joints can also bump hard into the heel bones on the back of the shell as the hypermobile ankle can allow for the foot to collapse in the midfoot which could force the heel bone rearward in the deepest flex position of the boot.

From the internet, I cannot assess either the range of motion of your ankle joint or what the situation is that caused heel pain in that boot and no heel pain in other boots that you owned.

Assessing the range of motion in the ankle joint has to be done in a manner that isolates the basic "saddle" joint of the ankle. To isolate the ankle joint the first thing to do is take the body weight off the joint and position the foot/lower leg in a neutral position where a repeatable read can be taken. You can do it low tech by simply using your eyes to see how big a gap between the floor and the 5th metatarsal head you can create. Me personally, I use my pinky finger and or 4th or third finger as my measuring tool for ankle ROM. You could also use a digital angle meter if you are a numbers kinda guy.

Basic premise... Seated position in a chair or bench that will have the femur parallel to the floor when the feet are flat on the floor and the lower leg comes off the feet at 90 degrees, the femur should create a 90 degree angle to the lower leg, and the back should be 90 degrees to the femur at the hips, meaning that your body mass is mainly supported through your ass sitting on the bench or chair and your feet are semi weighted on the floor. Your thighs, shins, and feet should all be parallel and approx hip width apart so there are no diverging or converging angles of right or left side. With out any directional torque of the foot, the fitter would hold your heel bone to the floor as you lift your met heads as high as you can in a direct line towards the knee. In this position you would either measure ( for me with my pinky finger ) directly underneath the 5th met head to see how big or small the range is. Few or no fingers is tight, 2 fingers is normal, and greater than 2 is headed towards hyper.

So normal ROM for humans is 10 to 18 degrees for dorsiflexion. Below 10 degrees is tight and over 18 degrees is hyper. To find the matching net forward lean for the set-up of the skier that you are looking at is simple math of subtracting the ramp angle of the bootboard from the forward lean angle of the boot spoiler. So if the skier has an ankle that is 1 pinky finger that means that their number is going to be below the 10 degrees of a normal ROM ankle. If the boot spoiler is 17 degrees of FL, and the bootboard stock out of the box is 4 degrees, you would subtract the bootboard number, from the FL number and in this example the net number is 13 degrees. The ankle in this example is only one finger, so for this example the ankle has about 8 degrees ROM. How do we get the net FL number to match the action of the ankle joint? We get the net forward lean number to match the ROM of the ankle. So for this boot we cold raise the heel height to make the bootboard ramp angle to be higher ( lets say that we raise it enough to make the ramp angle 7 degrees), and then take off the FL shim that was screw riveted to the spoiler. This will make the boot FL go to 15 degrees. Now subtract 7 from 15 and the net FL angle of the boot is now 8 degrees... Bingo!!! A love match between the ankles ROM and the boot that the ankle is going into.

Brilliant, thanks very much @otto , that's a great description and exactly what I was looking for.

I measured the angle using this method with my phone clinometer app lined up along the sole of my foot. I got 15 deg of dorsiflexion. So if I want to get the net forward lean of the boot as close to this as possible? So if I have a boot with a stated 14 deg cuff, and a 4 deg ramp angle that is 10 deg net. I can add a spoiler shim to increase this some and then will be close?

Then, am I right in thinking from earlier posts in this thread that you address and fore/aft balance issues with changes outside the boot, such as shims under the binding or on the boot sole etc...?

 

[Duplo]

Oh, and @otto , yes, thanks very much for that reply in the other thread. I took your advice and left the area around the cuff release well alone!

 

[otto]

Brilliant, thanks very much @otto , that's a great description and exactly what I was looking for.

I measured the angle using this method with my phone clinometer app lined up along the sole of my foot. I got 15 deg of dorsiflexion. So if I want to get the net forward lean of the boot as close to this as possible? So if I have a boot with a stated 14 deg cuff, and a 4 deg ramp angle that is 10 deg net. I can add a spoiler shim to increase this some and then will be close?

Then, am I right in thinking from earlier posts in this thread that you address and fore/aft balance issues with changes outside the boot, such as shims under the binding or on the boot sole etc...?

Yes, you can increase the FL number by adding a forward lean wedge. You can also adjust the net FL by either raising the toe of the bootboard a mm or 2. You could also lower the heel height of the bootboard by a mm or 2. This will get you the net FL closest to your measured 15 deg, give or take a degree. Raising or lowering might effect the overall fit of the boot, however I would always suggest getting the net forward lean correct first, then finalize the fit.

Example of raised toe to reduce the ramp angle of these bootboards...

Example of lowered heel on a bootboard. Stock it had a ramp of 5.2, modified it's ramp angle is 3.2


Yes, once the ankle is balanced inside the boot, then it is ok to play with the delta of the binding or the boot outsole. Keep in mind that all bindings on the market have a different delta from heel to toe even models of the same brand can be different. Because it is poorly misunderstood by the general skiing public, it is really easy to believe that if a little heel height or a little toe height is good, that must mean that a lot of delta change must be even gooder... MM mean a lot!!! The majority of humans are just fine balancing on skis with the heel of the binding having somewhere from + 0.5 to +2 mm of differential to ski any and all conditions. There are some exceptions where a slightly higher heel will be a benefit. And just cause it is a possibility, every now and again you will find that bye raising the toe +0 to +2 mm could benefit that skier in certain conditions. Also keep in mind that with tip and tail rocker on some ski models the sweet spot of balance can shrink to the size of a postage stamp.

 

[Philpug]

We were talking to the folks at Kastle, their new race boot will have a ramp of about 1.7*.

 

[Noodler]

We were talking to the folks at Kastle, their new race boot will have a ramp of about 1.7*.

That is a significant departure from the mainstream. Very, very interesting...

 

[Aquila]

Well this is all reasonably useful to know, I am getting new boots before my season starts and I know that we will cant the soles but I have wondered if I should get them canted at the same time I get them fitted, or wait until I ski on them a bit first. Looks like there's enough to be going on at the initial fitting with w.r.t. forward lean and ramp angles....

 

[Philpug]

I know that we will cant the soles but I have wondered if I should get them canted at the same time I get them fitted, or wait until I ski on them a bit first.

If you know that you will need canting, why would you wait?

 

[Aquila]

If you know that you will need canting, why would you wait?

Well that's just a great question... maybe it does make sense to do it at the same time. I wasn't sure if anything would change from skiing on them initially and then making further fit adjustments/grinding, which would affect the amount that the soles are canted.

 

[otto]

Hey @otto , what was your assesment of Daviv McPhail’s bootboard angle determination?
He was starting there, determining it by activation of the stretch reflex. I could never quite understand it. He ended up with very low angles like 2.3 degrees I think. Maybe 3.2.

James,

McPhail has done some interesting things at a place and time that may or may not stand the test of time. His success with a few key Canadian athletes is worthy of respect. I get a little pie eyed when we start getting into .1's and .2's of mm or degrees. You will notice that all bootboards that have been measured by the suppliers or by race boot builders like me do not have any decimal points, and I tend to round up or down the actual degrees of ramp angle. The human body in amazingly adaptable. Get the skier close and they are fully capable of adapting to perfection. The current crop of modern performance boots tend to have spoilers and lowers with 12 to 17 degrees and bootboards depending on boot size that have bootboards in the 3 to 5 degree range. There are 2 things that I agree with. Those 2 things are that the bootboard ramp angle is a key element of balance and performance in modern ski boots, and the control that the tongue has over the foot with down pressure is an important element of holding the foot down and into the back of the boot.

You didn't ask, but I have to say that his Birdcage Experiment was carried out in a time when skis where still very straight and long, and in that time period downhill racers were still winning races on Raichle 3 piece shells. If you want to go back in time, I think you could figure out what many of us know and that is the boots and skis we have today are way better than the gear from the 80's and 90's. As are the tactics and techniques we use today to set modern ski racing warriors up for success.

 

[Triplet]

So one achieves the right tongue down pressure with a matching instep height of the boot ? So that the boot itself holds your heel back in the heel pocket? Custom liners help, i guess