Cold Feet: The Power of Pedorthics for Winter Sports

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By Morgan Stanfield
Stephen McDonald

Stephen McDonald skiing in good form. Photograph courtesy of Stephen McDonald.

What kind of magic keeps a man alive when he's snowboarding down a 60-degree slope from a 22,000-foot summit? For Stephen Koch, the only man to snowboard on the highest peak on every continent, there's an answer beyond unmatched skill and inhuman confidence: Koch has a great pedorthist.

"Before I knew about pedorthic bootfitting, I really did damage to my feet, getting frostnip and building bone spurs that were completely preventable," says Koch, a motivational speaker, professional boarder, and guide. "People really need to know that they can have a great boot fit and that it can literally change their lives on the snow. The pedorthist is key to that."

Though pedorthics for winter sports may be a step aside from the typical pedorthic fare of pathological feet and diabetic shoes, Stephen McDonald, CPed-who is Koch's pedorthist-asserts, "most CPeds can become excellent [winter sports] bootfitters because they understand anatomy and biomechanics. They just need [to know] the nuances of different boots and sport-specific issues." This article will focus on the basics of serving snowboarders and skiers.

Amsbury

Amsbury

High-Level Assessment

To achieve perfect fittings for this high-activity patient population, the pedorthist's options range from adding off-the-shelf orthotics to existing boots to choosing and modifying new boot shells, wedging boots and bindings, custom-molding liners, and fabricating custom orthotics.

According to Brent Amsbury, CPed, owner of Park City Ski Boot & Pedorthic, Utah, to accurately determine what this population needs for optimum safety, comfort, and performance, "you need to do a very comprehensive, analytical assessment of the client.... That includes activity and medical history, complaints and concerns, and what they want to achieve, so you can set up reasonable outcomes for them. For instance, if you have someone who is a big sports enthusiast but is older, diabetic, and has a history of neuropathy, those things are going to be very important to take into consideration for the ski boot, footbed, and liner."

McDonald, who is also the staff pedorthist at Jackson Hole Mountain Resort, Wyoming, and owner of Teton Sports Orthotics, Jackson Hole, emphasizes examining patients' bare feet and lower legs at eye level and checking range of motion (ROM) and the condition of the skin, muscles, and nails.

Perfect Balance

Witherell

Witherell

Whichever boots your patients wear, they are "not, I repeat, not shoes," stresses Warren Witherell, author of the 1972 book, How the Racers Ski, which introduced the concept of the carved turn in skiing. "They're functional equipment for transferring energy from the athlete to the edges" of the skis or snowboard. For even the most casual participant, Witherell told The O&P EDGE, any boots must be tuned to precisely balance the wearer in both the coronal and sagittal planes; otherwise, the athlete cannot transfer his or her energy efficiently. During standing, boot heels must be wedged until the patient feels maximum relaxation in the legs and trunk, signaling that balance has been achieved and the muscles are no longer performing unnecessary work to hold up the body.

Amsbury estimates that in this position, the foot will be dorsiflexed inside the boot to approximately 10 degrees. When the skier drops into a bent-knee stance with approximately 25-30 degrees of dorsiflexion, the front of the shoulder, center of the hip, and midfoot should be stacked vertically in the sagittal plane. Amsbury notes that it's essential to find the ramp angle on each side that allows the patient to achieve this neutral stance. At the angle that's right for some people, others may "compensate with upper-body movement for what they feel is now an unbalanced position. They might bow forward at the waist or throw their shoulders backward like they're doing the limbo.... Their skiing will be out of control, and the instructor will have a very difficult time getting them into the optimal position."

To establish sagittal-plane balance, Witherell recommends having the patient stand in the ski boots on a flat surface. If the bottom of each boot does not land absolutely flat on the floor in the medial-lateral plane-and Witherell estimates they won't in 80 percent of patients-wedges should be built that cant the knees to an absolutely flat stance for men. For women, Witherell recommends wedging to set the skis one-half to one degree on their outside edge. These wedges should be installed under the ski binding, in two pieces to prevent buckling-one piece under the heel and the other covering or beneath the antifriction plate.

Getting the Boot

For any professional who helps a client choose a boot, it's essential to understand the variations among boot shells. Manufacturers tend to be loyal to their established basic fit, but each boot model has particular fit characteristics that are rarely described in brochures. Patrick Nelson, owner of earlyups.com, a website that showcases freeskiing content, notes, for example, that "manufacturers have flex ratings listed on their boots, from 90 as a really soft flex, going all the way up to 130. Those are pretty arbitrary numbers, though-in one boot 120 might be the same as 100 in another."

Classes that can help teach such characteristics are available nationwide through companies such as MasterFit University, Briarcliff Manor, New York; and McDonald's own Jackson Hole Boot Camp program. Amsbury notes that for those who would like to learn on their own, mining the boot companies' websites for technical data on each boot is a good start. Also, distribution centers for each company oftentimes will provide technical datasheets for each boot they sell.

A Firm Handshake

"Ski boots are compressive devices that can create hotspots along bony prominences, neuropathic responses, or numbness. They're also challenging to get in and out of," Amsbury says. Because of this, "The number one thing that any fitter is asked to deal with is pain reduction and comfort."

To optimally balance comfort and performance, the fit of winter sports boots should approximate a very firm, but not painful, handshake, except in the toe region, where spacing will vary based on a variety of factors including typical terrains skied and foot pathologies. This fit is based on both the size of the boot shell and the qualities of the boot liner. A typical toe space for casual skiers with healthy feet is one-quarter inch, while downhill racers may want their toes to lightly touch the ends of the boots during skiing stances. Koch, for whom warmth and good circulation are safety features, has his boots fitted while wearing a toe warmer. He also lays a strip of foam over his dorsal tendons to ensure adequate circulation, a factor in what McDonald calls a "big mountain fit."

The boot liner, whether original to the boot or aftermarket, is integral to overall fit. Liners are meant to be compressed from their original shape to fit the foot, a process known as "packing out." Many stock liners are thermoformable as well; some professionals recommend heating these liners, while others let liners compress naturally, which may extend the life of the foam. Thermoformable ethylene-vinyl acetate (EVA) aftermarket liners by Intuition, Vancouver, British Columbia, are highly praised for their light weight, relative softness, ease of use, and suitability for patients with diabetes or neuropathy. For high-performance athletes and those whose foot shapes aren't a good match for their boots' last, some interviewees recommended injectable cork or catalyzing foam liners such as those made by Conform'able, Voiron, France, and Scarpa, Asolo, Italy. For patients who struggle to don and doff boots, Scarpa also makes both liners and boots that are entered from the side.

Graham

Graham

Building the Insole

To create or select the right insole, materials and biomechanics take precedence. Brian Graham, CPed, whose Lake Orion, Michigan, practice serves many of the top college and pro athletes in the state, is a former associate instructor for MasterFit University. He strongly recommends the use of softer materials in winter sports orthotics.

"If you use rigid materials like carbon fiber or heavy polypropylene inside a ski boot, it can rock on top of the footboard," he explains. "If it's EVA, and you've shaped the interface properly, it will fit nicely and adapt to the contour of the footboard and the foot. It also allows the patient to subtly pronate and supinate their foot without forcing the knee into a poorly aligned position." He adds that patients with even subtle cavus foot or other causes of tibial genuvarum will especially struggle if the foot is excessively restricted.

Graham's view isn't the only one, however. McDonald, like many other pedorthists, prefers semirigid carbon fiber orthotics, albeit built to low volume. McDonald concurs, though, that alignment begins with bringing the foot as close to subtalar neutral as possible. This optimizes the patient's ability to shift from one edge of the ski or board to the other while preventing tibial torsion and stresses on the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and medial collateral ligament (MCL). McDonald also cautions that most off-the-shelf orthotics have heel flanges that are too high for skiing and arches that are too short. The latter problem can potentially cause forefoot valgus. In such cases, he recommends using an orthotic with the correct-length arch and trimming down as needed.

Witherell points out that if the orthotics' main arch or metatarsal arch is too high, it destroys the architectural purpose of the foot's natural arches and can lead to a variety of biomechanical problems, bone spurs, and pain. He also notes that women with higher arches are more likely to need a higher heel lift to prevent them from loading excessive weight onto the back of their skis.

For all the expert advice available, though, Graham concludes that none of these practices should be considered set in stone. "To do this work right, you have to try experimenting and questioning-there isn't one way to do it. Listen to the patient and make good observations. You can never know everything."

Morgan Stanfield is a freelance communications specialist and journalist based in Boulder, Colorado. She can be reached at