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Reprints From The Professional Skier

Fall 1999 - "The Ups & Downs Of Ramping The Foot" by Greg Hoffmann

This article is reprinted from The Professional Skier. All copyrights apply. Please see our copyright and disclaimer notice page.

When the editors of The Professional Skier called and asked if I would be interested in writing an article about ramp angle and the effects it has on balance, I should have pretended I was the telephone repairman checking the line. Or, I could have feigned temporary amnesia. "Master bootfitter? Oh no, I'm not a master bootfitter. I'm the ambassador to Papua New Guinea ... I think."

Or, or I could have offered to write on an easier topic, like quantum physics. But no. Honorbound to my profession I just had to step up to the ramp angle plate. "Absolutely. You bet!" I said.

But no sooner had I heartily agreed to put fingers to keyboard when a sense of panic hit. Where do I start? I asked myself. I mean, this stuff is fairly technical, inspiring the "glaze factor" in many an eye. Even so, instructors need to understand the principles and effects of ramping--for their own benefit as well as that of their students. Committed to the cause, I decided to just wade in (with a mantra of Don't burn them out with Latin pounding in my head).

Okay, so let's start with a few basics. The first thing a skier notices when he or she puts on ski boots--aside from the fact that they give Doc Martens a run for their money on the clunkiness scale--is that the heel is higher than the toe. This so-called "heel-high attitude" is achieved by placing the foot on a ramped bootboard, which is either removable or molded into the boot. The second sensation the skier notices is that the boot cuff pitches him or her into a slight forward lean. The incline of the bootboard is referred to as "ramp angle." (Ramp angle can also be produced within the interface of ski and binding and is usually called "delta," but I'll get into that later.)

Why do we have ramp angle in our boots? At the heart of the matter is the fact that alpine skiing is a dynamic course sport that takes place on hills--some steeper than others, of course. The theory behind ramp angle is that raising the foot at the heel adding forward lean to the boot cuff helps skiers lean downhill more so they can keep up with the acceleration of their skis and get their weight forward--centered somewhere over the ball of the foot. And this seems to work for an awful lot of people! But for some, the ramp angle in their boots can compromise stance, balance, and overall skiing performance. Ramp angle reasoning seems sound, so why doesn't it work for everybody?

While it's true that we're all mouth breathers and semi-erect bipedal organisms, comparisons beyond that can get a little muddy. Unfortunately any biomechanical similarities in people are only gross generalizations once they buckle into a hard plastic, cast-like shoe, click into a slippery high-tech barrel stay, and succumb to the exhilaration of speed, gravity, and centrifugal force. Then it becomes obvious that, like snowflakes, no two people are alike.

Be that as it may, the charge of every bootfitter is to make sure the skier's boots offer optimum performance while making the most of his or her biomechanics. And the most important aspect of a skier's biomechanics is the range of motion available at the ankle joint. After taking a series of measurements with a protractor, we can determine how much range of motion a given individual needs to achieve a balanced, grounded, and centered stance in the boot.

In bootfitting parlance, "balanced" means that the center of each knee is aligned with the molding seam at the toe box of the boot, the center of each hip is aligned over the instep buckle, and the torso is evenly aligned over the hips. "Grounded" means the entire bottom of the foot is bearing weight, and "centered" means that from a side view the knee is not flexed beyond the toe box of the boot, the hips are over the instep buckles, the torso is over the hips, and the skier's ears are ahead of his or her hips. By measuring the boot's forward lean and ramp angle with a tool known as a digital smart level and subtracting the ramp angle from the forward lean, we discover the static angle of ankle flexion required just to have the foot grounded in the boot.

Here's a simple do-it-yourself test for ankle-joint flexion. Take your shoes off and sit in a low chair with your spine erect, your thighs parallel to the ground, and your lower legs at a right angle to the floor. Place your feet flat on the floor and see how far you can lift up your forefoot while leaving your heel on the ground. In terms of ankle flexion, a measurement of less than 2 inches is tight, 2 to 3 inches is good, and more than 3 inches is loose.

The heels of skiers with inadequate ankle flexion will feel loose in their boots, i.e., "lost in space," and their hips will be on the tail thrusters trying to keep up with the ship. Ever wonder why skiers sit back? Typically it's because they are so tight in the heel cord, or Achilles' tendon, that the in-boot combination of too much forward lean and not enough heel height keeps them from being grounded. The classic reaction is to drop the hips back to get the weight bias over the heels, thus forcing the heels to the ground.

These skiers tend to ski with a fairly hunched, rounded, upper torso and internally rotated legs. This internal rotation is what allows the hips to drop far enough to push the heels down. When venting their frustrations to their instructors, these skiers often complain that, because their heels feel loose, they need to have extra material added to their boot liners to fill the void around the Achilles' tendon. Well, their heels are loose because they are nowhere near the bottom of the boot. They will also look as if they need to lean forward, feel more shin-to-boot tongue contact, and perhaps focus on getting their weight to the ball of the foot. But indeed, this is the only place that is on the ground! A surefire fix for these space explorers is to add heel lift to the boot board and reduce the forward lean of the boot cuff. These two elements generally work in tandem, one without the other is usually not enough. The amount of heel lift needed will vary, depending on the boot and the skier's personal biomechanics. Bootfitters can obtain minimal lift with a couple of layers of duct tape or up to one inch of lift with a high-density foam wedge. In simple terms, the purpose of the heel lift is to bring the ground up to the foot so the body won't have to compensate to find it.

Straightening the cuff permits greater range of motion at the ankle and keeps the tibia and fibula more erect, thus allowing the hips to push forward. In addition to allowing forward motion of the hips, these adjustments also promote external rotation of the legs, which aligns each knee somewhere in the vicinity of the center molding seam at the boot's toe box. This may negate the need for under-binding cant shims-the small wedges of plastic that many skiers use to adjust for optimal leg alignment. To recommend cant shims without first understanding the ankle joint's range of motion is doing a great disservice to the skier. Decreasing the ramp angle for these hapless skiers will doom them to suffer tendonitis in the Achilles' tendon within a few runs! Their heel cord is already tight, and lowering the ramp angle will only make it tighter. As a guy named Newton was fond of saying, "Every action has an equal and opposite reaction." You can't fiddle with one plane of motion without affecting another, nor can you work on edging without affecting rotary movement and the other fundamental skills of skiing.

Just as there are folks with a limited range of motion at the ankle joint there are some who have too much. You might find it hard to believe that in today's Tae-Bo society too much elasticity can be bad, but again, just imagine strapping on a boot, clicking into a ski, and tipping the playing field. Skiers who have too much flexibility tend to overflex at the ankle in an attempt to use up elasticity. This overly flexed posture turns these folks into masters of short-swing, windshield-wiper turns.

A common complaint of these skiing Gumbys is that "it's hard to find the middle of my foot in the ski boot." Because their boots don't offer enough resistance to reduce their ankle flexion, their bodies tell them to create a strong feeling at the Achilles' tendon, making it more taut as opposed to relaxed. This type of skier will likely flex only at the knee and hip because the range of motion at the ankle is all used up! As the skier's knees and hips flex and extend, the hips tend to move more in a vertical plane as opposed to a diagonal plane down the hill. Despite all the body motion, there's hardly any reaction at the ski-snow interface--something I call the Wile E. Coyote Syndrome.

Bootfitters often recommend stiffer boots for a skier with excessive ankle flex, regardless of that person's level of skill development. This type of ankle-joint mechanics also responds well to a lower ramp angle. Stiff boots improve control of the lower leg shaft and a lower heel takes some elasticity out of the heel cord. As we lower the boot board to control the elasticity, we also straighten the boot cuff, which permits a more vertical orientation of the tibia. As the tibia becomes more erect, so does the femur. Consequently, the pelvis becomes more naturally aligned as well. The taller stance promotes better pressure control and slows down some of the rotary movement associated with windshield-wiper turns. The knee bone is connected to the thigh bone, etc., etc. We cannot affect one without affecting the others!

Remember, the ski boot is essentially a cast. All modifications inside the boot are meant to alleviate the body's need to compensate for this by somehow getting the foot on the ground.

Outside The Boot Ramp Angles

Up to now, the discussion has centered around boot ramp angles-but these aren't the only ramp angles bootfitters and their clients must contend with. Often overlooked by a huge majority of bootfitters and snowsports professionals are the effects of the ski/binding interface.

Think of your body type and all of the pieces of ski equipment you own as a system. Not surprisingly, it's crucial to recognize what parts of the system are promoting skill development and what parts are bringing down the ship.

Most skis are thicker at the toe mounting area than in the heel mounting area. This has absolutely nothing to do with a skier's biomechanics; rather, it has to do with how the ski reacts to the pressures of dynamic forces. The materials used to produce the ski also directly influence this variance in thickness.

What does this have to do with the subject? Nothing ... yet. However, at times it's important to know what these measurements are from ski to ski and manufacturer to manufacturer. For instance, if a male student looks really overflexed at the ankle and has a pair of slalom skis with pink bindings that have additional heel height geared toward women, the binding will be the obvious thing to fix first and not his skiing skills blend. The deficiency relates to equipment not athletics.

Imagine now that your boots are perfectly set up to put your feet in a grounded, balanced, and centered stance and you've selected a ski well suited to your skiing style and skill level. Now comes the time to put a binding on the ski, and lo and behold-the binding has a ramp angle, or delta, of its own. Why do bindings have delta? For no other reason than they need to be higher in the heel to accommodate the ski brake mechanism. Some need more room than others, so some heel pieces are higher than others. Manufacturers have done a lot of research in this area. Olin has introduced a ski line that has delta built into the ski, with differing amounts for men and women. Rossignol, on the other hand, now offers a race ski with negative delta. In an attempt to influence the placement of the skier's hips and the direction of hip travel during flexion and extension, some binding companies offer after-market lift kits that are thicker at the heel than at the toe.

So what does this mean? To put it simply, the equipment system can inhibit the learning curve. These equipment-oriented attempts to create a more aggressive, flexed stance and get the hips to flex own the hill rather than vertically work great for a vast majority of skiers but not for everyone. Keep in mind that the shorter a boot sole, the steeper the angle created by the binding/ski interface. Which gender typically has a shorter boot sole? And which gender is often accused of skiing with their hips too far back? Right-o! Women.

It's common practice to automatically add heel lift to women's boots to bring their hips forward, but this sometimes makes the hips go farther back. As the sole of the boot is lifted, on the outside of the boot, the forward lean of the cuff is also exaggerated. This pushes the lower leg forward and once again locks the ankle in end-range flexion--too far forward--which dictates that flexion and extension occur at the next available joints: the knees and hips. Extension will be severely limited because it relies solely on how far forward the skier can tip the boot cuff. In this situation it is better to go with less boot-cuff forward lean and zero ski/binding delta.

It seems that for a lot of the skiing public the increased delta does work. But there will always be some for whom extra delta is a bane of their skiing existence. Typical feedback from a skier who does not benefit from the increased delta is that their quads are "on fire," or "Man, I go to the gym every day, but I cannot believe my legs are so tired after two runs!"

The advent of delta in the modern ski can be an advantage for some, allowing them to keep up with the ski's ability to accelerate. For others, the angles will work great dynamically but they'll find that standing in a lift line is more tiring than skiing. The quads are always flexed!

Increased Boot Ramp and No Ski/binding Delta

Just as there are those who have a propensity to flex too far forward, there are skiers with the opposite problem. They have what I call the "Mr. Natural" complex. For those of you who don't remember him, Mr. Natural was the coverboy for Zap comics--the guy who in the 1970s became forever identified with the tagline, "Keep on Truckin'." Mr. Natural had one heck of a biomechanical problem; his feet were amazingly far ahead of his hips and torso.

This is the toughest of all body types to deal with on the hill. On a clinical level, these skiers are said to have a "posterior ilium," which means that the top of the hip or iliac crest is behind the lower hip. People with the posterior ilium stance tend to scuff along while walking in their boots as opposed to having an actual heel strike. Also, when standing barefoot or in street shoes, they tend to stand with their knees hyperextended. And when they rest their hands on their hips, in a James Dean-like pose, their thumbs will point up toward the front of their bodies.

These people usually ski with their legs externally rotated and excessively flexed but complain that they cannot feel the tongue of the boot with their shins. They are experts in the fine art of riding the outside edges and, well, they're scary to ski with. With the external rotation of their legs, their turns are anything but C-shaped. They generally go as fast as possible in an attempt to break the friction between their skis and the snow. Not only do they ski way too fast for any given terrain, but there is always a huge amount of vertical motion--once again in an attempt to lessen friction with the snow.

The instinctual thing to do is to get a huge wad of trail maps and try to increase the ramp angle in the boot. Good idea but bad execution. This only fills the void under their heels, doing nothing to affect the hip or external leg rotation. Imagine trying to do the limbo. In fact, try the following "test" in the comfort of your own living room. Stand up and allow your body to assume a casual limbo pose. Now walk forward as if the limbo bar is shoulder high. Then allow the imaginary bar to get lower and lower. What happens? In order for your shoulders to go back, your hips have to move more posteriorly, your legs have to externally rotate, and your heels have to come off the ground. Obviously, this isn't a balanced skiing stance.

When bootfitters add heel lift to "Mr. Natural's" boots this is exactly what happens. Everything is back but his heels are grounded. Bootfitters find that adding flat shims under the toe binding piece promotes better alignment of the hips and a much taller stance. This is the only fix for this type of posture.

It may seem contradictory and confusing to have heel lifts in the boots and toe lifts under the binding, i.e., zero delta, but we are talking apples and oranges. Modifications in the boot address the biomechanics of the ankle and subtalar joint primarily, with a secondary effect on the legs and hips. Modifications outside the boot primarily affect the legs and hips.

There are a lot of people who ski today's modem skis with toe lifts under their bindings. This is especially true at the World Cup level. These athletes are so strong and going so fast that they can collect frequent flyer points every time they extend in a turn. The toe lift allows the ankle to really open up, the leg is long and stretched in extension, and the hips are more erect, leading the body down the hill.

For us mere mortals, zero delta certainly allows us to stand taller; and the first reaction is that this feels cool. Cool, however, is not necessarily good. Zero delta allows the skier to exert less effort to get more reaction at the ski tip, and while this is fine for most of us on mellow terrain, once the pitch gets demanding or the terrain turns bumpy it's difficult to absorb the forces at hand.

There are no cookie-cutter answers to the questions that crop up with regard to equipment set up. I'm not suggesting that all snowsports professionals carry a plumb bob and heel lifts in their parkas. The point is that there are as many different boot, binding, and ski configurations as there are body types these days.

By learning how the different equipment systems relate to specific movement patterns, instructors will see a bigger picture with regard to student performance. This added expertise can also open the door to a better working relationship with bootfitting personnel at local ski shops and the on-mountain demo center. In the long run, such knowledge and rapport can help create better skiers and the potential for an insatiable private-lesson request list.

Greg Hoffmann is a certified pedorthist and orthopedic shoe technician who owns and operates Green Mountain Orthotic Lab and an on-hill performance center at Stratton Mountain, Vermont. He is on the education staff of MasterFit University, the country's leading boot technician training resource, and has been a featured speaker at PSIA's National Academy. He can be reached via e-mail at gmol@sover.net