Living on the Edge: The Biomechanics of Power Skatingcenter of gravity move in an opposite direction...

of power skating. The podiatric assis-tance in foot and lower extremity bal-ance on top of a narrow balance point, the skate blade, will allow a practi-tioner to assist in both improved perfor-

mance and overuse injury patterns. In order to better understand the biomechanics of power skating and the clinical injury perspectives that may arise, it is first helpful to compare power skating with the more common-ly understood biomechanics of walk-ing. Both walking and skating are bi-phasic movement patterns that consist

Ice skating in all its various forms has shown increased popularity worldwide. Olympic speed skat-ing champions are coming from areas of warm climate and ice

hockey teams are starting up in almost every populated geographical location. A close cousin to ice skating is in-line skating, which is a similar biomechan-ical activity and is another common recreational and fitness endeavor. The increasing popularity of skating makes it likely that all podiatric practitioners will benefit from a fundamental under-standing of the management of this ath-letic population, regardless of practice location. Ice skating involves three disci-plines: figure skating, speed skating and power skating. It is power skating that defines the unique skating patterns and mechanics of locomotion seen in ice hockey. The principles of podiatric bio-mechanics can be applied to all of these

skating disciplines, as many of the me-chanics of foot position and balance are similar. For the purposes of this article, however, I will focus on the biome-chanics of power skating (Figure 1).

Biomechanics Power skating in hockey involves skating forward, backward and with multiple directional changes as the game evolves. It is this ever-changing movement pattern that makes this ac-tivity difficult to study from a biome-chanical standpoint. It is forward accel-eration and striding, however, that are the most consistent and studied aspects

There are some very specific overuse injury patterns seen in the ice hockey population.

Living on the Edge: The Biomechanics of Power Skating

By R. Neil HumBle, DPm

www.podiatrym.com SEPTEMBER 2018 | PODIATRY MANAGEMENT

135

Both walking and skating are biphasic movement patterns that consist of periods

of single and double-limb support.

Continued on page 136

BiOmeCHANiCS

www.podiatrym.comSEPTEMBER 2018 | PODIATRY MANAGEMENT

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BiOmeCHANiCS

sion through full knee extension, hy-perextension of hip and plantar flexion of the ankle.

Clinical Injury Perspective Without a doubt the most common foot and lower extremity injury patterns seen in ice hockey are acute traumatic events. However, for the purposes of this article we will focus on the more common presenting problems in an office setting. There are, first, the com-mon dermatologic conditions seen in this patient population. Second, there are the intrinsic foot-to-boot injuries that can be precipitated from the nature of the unique footwear, and last, there are the specific biomechanically-pro-duced clinical injury patterns that may arise from overuse. A general understanding of skate anatomy and fit is necessary for a full understanding of the impact of com-mon podiatric pathologies, as well as for an understanding of the biomechan-ically-produced overuse injuries seen in the skating population (Figure 4). There is first the skate boot that is rigid for protection and support. Sewn skates generally fit one to one-and-a-half sizes smaller than one’s regular shoe size. Skates need to fit snugly and toes should “feath-er” the toe cap. All boots have a heel raise that may be from five degrees to nine degrees but can vary from one manufacturer to another. Next is the blade housing that is riveted or screwed onto the boot itself. The attachment of

of periods of single and double-limb support. By comparison, it is the sup-port phase of walking that becomes the skating glide. One aspect of skating that makes it unique in the support phase is that the friction on the per-formance surface is much less than that seen in most walking activities. As a result there are decreased posteri-or linear shear forces with touchdown due to decreased friction and decreased anterior linear shear forces in the late midstance to propulsion stage. This low friction surface will necessarily impart a need to abduct the foot by external hip rotation at propulsion.1 The center of gravity therefore does not progress in a linear sinusoidal path over the foot as seen in walking, but rather the skat-er and his/her center of gravity move in an opposite direction to the weight

bearing skate. The accelera-tion in power skat-ing is divided into two unique stride patterns, the first three strides and the fourth stride, known as the typical skate cut.2

The first stride pattern usually in-volves the first three strides (Figure 2). It lasts approximate-ly 1.75 seconds, involves continual positive acceleration and has a negligi-ble or non-existent glide phase.3 It is during this stride pat-tern that the skater often appears to be “running” on his/her skates.

The second str ide pat tern often begins on the fourth stride and is considered the typical skate cut2 (Figure 3). This stride pattern consists of periods of positive and negative accelera-tion and involves three phases. It starts with a glide during single limb support which imparts negative acceleration.4 It continues with propulsion during single limb sup-port which is ac-complished by ex-ternal rotation of the thigh and the initial extension movements of the hip and knee.5 This stride pattern concludes with propulsion during double limb sup-port. During this phase the second limb acts as a balance point to complete propul-

Living on the Edge (from page 135)


that may arise, it is first helpful tocompare power skating with themore commonly understoodbiomechanics of walking. Bothwalking and skating are biphasicmovement pat-terns that consistof periods of sin-gle and double-limb support. Bycomparison, it isthe support phaseof walking thatbecomes the skat-ing glide. One as-pect of skatingthat makes itunique in the sup-port phase is thatthe friction on theperformance surface is much lessthan that seen in most walking activ-ities. As a result there are decreased

posterior linearshear forces withtouchdown due todecreased frictionand decreased ante-rior linear shearforces in the latemidstance topropulsion stage.This low frictionsurface will neces-sarily impart a needto abduct the footby external hip ro-tation at propul-sion.1 The center ofgravity thereforedoes not progress ina linear sinusoidalpath over the footas seen in walking,but rather theskater and his/her

Biomechanics Power skating in hockey in-

volves skating forward, backwardand with multiple directionalchanges as the game evolves. It isthis ever-changing movement pat-tern that makes this activity diffi-cult to study from a biomechanicalstandpoint. It is forward accelera-tion and striding, however, that arethe most consistent and studied as-pects of power skating. The podi-atric assistance in foot and lowerextremity balance on top of a nar-row balance point, the skate blade,will allow a practitioner to assist inboth improved performance andoveruse injury patterns.

In order to better understandthe biomechanics of power skatingand the clinical injury perspectives

center of gravity move in an oppositedirection to the weight bearing skate.

The acceleration in power skat-ing is divided into two uniquestride patterns, the first three

strides and thefourth stride,known as thetypical skate cut.2

The first stridepattern usuallyinvolves the firstthree strides. Itlasts approxi-mately 1.75 sec-onds, involvescontinual posi-tive accelerationand has a negligi-ble or non-exis-

tent glide phase.3 It is during thisstride pattern that the skater oftenappears to be “running” on his/herskates.

The second stride pattern oftenbegins on the fourth stride and isconsidered the typical skate cut.2

This stride pattern consists of peri-ods of positive and negative accel-eration and involves three phases.It starts with a glide during singlelimb support which imparts nega-tive acceleration.4 It continues withpropulsion during single limb sup-port which is accomplished by ex-ternal rotation of the thigh and theinitial extension movements of thehip and knee.5 This stride patternconcludes with propulsion duringdouble limb support. During thisphase the second limb acts as a bal-ance point to complete propulsionthrough full knee extension, hyper-extension of hip and plantar flex-ion of the ankle.

Ice Skating...


50 www.podiatrym.comPODIATRY MANAGEMENT • NOVEMBER/DECEMBER 2003

Figure 1: Ice hockey, power skating.

The most common footand lower extremity

injury patterns seen inice hockey are acute

traumatic events.

Figure 1: Ice hockey, power skating













Ice Skating...






traumatic events.













Ice Skating...






traumatic events.

Other than traditional podiatric treatments one may alleviate the skate counter pressure with internal or ex-ternal heel lifts, accommodative ad-hesive felt padding within the skates,

or expansion of the heel count-er by a local skate shop. A w e l l - p o s t e d custom foot or-thotic can also decrease the movement of this prominence within the skate. The tight fit of skates can also increase the in-cidence of Mor-ton’s neuroma and dorsal su-perficial com-

pression neuropathies. Proper boot structure, along with the necessary biomechanics of skating, can decrease the frequency of com-plaints from certain pathologies. Hal-lux limitus, Achilles tendonopathy and plantar fasciitis are all less commonly a


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problem during skating activities. Biomechanically-produced overuse foot and ankle clinical injury patterns can clearly be identified in ice skating. The narrow blade or balance point cre-ates need for strenuous eccentric mus-cle control and proprioceptive skills to assist in balance over this small balance point. As a result, general foot fatigue from strain of the small intrinsic mus-cles of the foot are common. As well as the intrinsic muscle strains, there are the extrinsic tendonopathies that can occur in the posterior tibial tendon and the peroneal tendons and muscles as a reaction to the need for balance. In comparison to other sporting activities, power skating shows a de-crease in the number of contact phase injuries due to the low friction of the ice surface. The overuse injuries in the lower extremity usually show up more proximally in the groin or low back due to the inherent need for skate and skat-er to be moving in opposite directions as propulsion occurs. Groin injuries in the adductor muscle group (adduc-tor magnus, longus and brevis) occur when the thigh is externally rotated and

the blade housing to the boot can be a point of biomechanical input. This housing can be moved medial to lateral, or anterior to posterior on the boot. Its standard position is to hold the blades centrally under the heel to continue for-ward under the second metatarsal head and further forward through the sec-ond digit. The blade housing can also act as an attachment site for heel lifts and wedges as they are sandwiched between the housing and boot. Lastly is the narrow blade, which can also be adjusted for biomechanical effect. It is rockered front to back and is hollow ground on the bottom surface to create a medial and lateral edge or bite angle. The blade acts as a balance point and as little as one inch is all that normally contacts the ice surface (Figure 5). As mentioned above, skates need to fit snugly, and as such many skaters wear their skates without socks for a better “feel.” This practice should be discouraged due to the dermatological consequences from both friction and hygiene. Blisters, corns, calluses, tinea pedis, onychomycosis, and verrucae are common in this patient popula-tion. Use of general podiatric principles along with a thin, well-fitting perfor-mance sock with both hydrophilic and hydrophobic properties will decrease friction within the boot and im-prove hygiene. If thin enough, it will still allow the “feel” needed for performance. The specifici-ty of the footwear and its need for a performance fit can also cause friction and pres-sure injuries at the interface be-tween common structural foot deformities and the boot. Common podiatric patholo-gies such as hammertoes and bunions are a painful dilemma in this footwear and are treated in the usual fashion. Haglund’s deformity, however, is an especially difficult problem for skaters (Figure 6).



Clinical Injury Perspective Without a doubt the most com-

mon foot and lower extremity injurypatterns seen in ice hockey are acutetraumatic events. However, for thepurposes of this article we will focuson the more common presentingproblems in an office setting. Thereis, first, the common dermatologicconditions seen in this patient popu-lation. Second, there are the intrinsicfoot-to-boot injuries that can be pre-cipitated from the nature of theunique footwear, and last, there arethe specific biomechanically-pro-duced clinical injury patterns thatmay arise from overuse.

A general understanding of skateanatomy and fit is necessary for a fullunderstanding of the impact of com-mon podiatric pathologies, as well asfor an understanding of the biome-chanically-produced overuse injuriesseen in the skating population. Thereis first the skate boot that is rigid forprotection and support.

Ice Skating...



Figure 4: Skate Anatomy

Figure 4: Skate Anatomy

boot itself. The attachment of theblade housing to the boot can be apoint of biomechanical input. Thishousing can be moved medial tolateral, or anterior to posterior onthe boot. Its standard position isto hold the blades centrally underthe heel to continue forwardunder the second metatarsal headand further forward through thesecond digit. The blade housingcan also act as an attachment site

Sewn skates generally fit one toone and a half sizes smaller thanone’s regular shoe size. Skates needto fit snugly and toes should“feather” the toe cap. All bootshave a heel raise that may be fromfive degrees to nine degrees butcan vary from one manufacturer toanother. Next is the blade housingthat is riveted or screwed onto the

for heel lifts and wedges as theyare sandwiched between the hous-ing and boot. Lastly is the narrowblade, which can also be adjustedfor biomechanical effect. It is rock-ered front to back and is hollowground on the bottom surface tocreate a medial and lateral edge orbite angle. The blade acts as a bal-ance point and as little as one inchis all that normally contacts theice surface.

As mentioned above, skates needto fit snugly, and as such manyskaters wear their skates withoutsocks for a better “feel.” This prac-tice should be discouraged due tothe dermatological consequencesfrom both friction and hygiene. Blis-ters, corns, callouses, tinea pedis,onychomycosis, and verrucae arecommon in this patient population.

Use of general podiatric principlesalong with a thin, well-fitting per-formance sock with both hy-drophilic and hydrophobic proper-ties will decrease friction within theboot and improve hygiene. If thinenough, it will still allow the “feel”needed for performance.

The specificity of the footwearand its need for a performance fitcan also cause friction and pressureinjuries at the interface betweencommon structural foot deformitiesand the boot. Common podiatricpathologies such as hammertoesand bunions are a painful dilemmain this footwear and are treated inthe usual fashion. Haglund’s defor-mity, however, is an especially dif-ficult problem for skaters.

Other than traditional podiatrictreatments one may alleviate theskate counter pressure with internalor external heel lifts, accommoda-

Ice Skating...




139

BiOmeCHANiCS

As a skater is in single-limb support in the early stages of propulsion, the foot is abducted and the hip externally rotated. The skate and skater are mov-

ing in opposite directions at this time while trying to balance on the narrow skate blade. As such, the center of gravity is much more medial with respect to the weight-bearing extremity, and even subtle biomechan-ical faults, causing excessive foot pronation, will cause a skater to spend too much time on the medial skate edge. Power and efficiency are created by staying on

the hip is abducted, thus putting this muscle group under maximal strain. Dr. Eric Babins from the University of Calgary has reported a reduction in pain of the lumbar spine and lower extremity along with improved perfor-mance with proper fitting of skates, blade alignment and adjustment for leg length discrepancies as required due to the improved biomechanical balance above the skate blade.

Clinical Biomechanical Balance There are two steps in the process to assist a skater from a biomechanical perspective. The first is the positioning of the foot within the boot using stan-dard podiatric biomechanical princi-ples. The second is the balance of the blade onto the boot itself. Results from a recent pilot study (Baisch, Humble et al, 2013) suggest custom foot or-thoses as designed below can assist figure skaters with postural control. This small study showed better stability of both the ankle joint and the knee joint by reducing internal-external ro-tation range, all the while increasing flexion-extention range of both ankle and knee joint.

Step 1: Foot Balance Within Boot—Custom Foot Orthotic A general podiatric clinician can be confident when dealing with the first

step of biomechani-cal control, which is positioning the foot properly within the boot. A complete lower extremity and foot exam needs to be done as would be done for any athlet-ic population, and a decision on foot or-thotics can be made using sound Root

biomechanical tech-niques.6 These tech-niques of forefoot to rearfoot and rearfoot to leg control will help to compensate for biomechanical faults, help stabi-lize the subtalar and midtarsal joints, and help maintain sound structural alignment of the lower extremi-ty from the midtarsal joint to the hip, pro-viding a solid lever for propulsion. This orthotic can then be improved upon by using a general understanding of skat-ing mechanics and applying the newer techniques of foot orthotic control as discussed by Kirby and Blake.7,8



Ice Skating...

tive adhesive felt padding withinthe skates, or expansion of the heelcounter by a local skate shop. Awell-posted custom foot orthoticcan also decrease the movement ofthis prominence within the skate.The tight fit of skates can also in-crease the incidence of Morton’sneuroma and dorsal superficialcompression neuropathies.

Proper boot structure, alongwith the necessary biomechanics ofskating, can decrease the frequencyof complaints from certain patholo-gies. Hallux limitus, Achilles ten-donopathy and plantar fasciitis areall less commonly a problem dur-ing skating activities.

Biomechanical ly-producedoveruse foot and ankle clinical in-jury patterns can clearly be identi-fied in ice skating. The narrowblade or balance point creates needfor strenuous eccentric muscle con-trol and proprioceptive skills to as-sist in balance over this small bal-ance point. As a result, general footfatigue from strain of the small in-trinsic muscles of the foot are com-mon. As well as the intrinsic mus-cle strains, there are the extrinsictendonopathies that can occur inthe posterior tibial tendon and theperoneal tendons and muscles as areaction to the need for balance.

In comparison to other sportingactivities, power skating shows a de-crease in the number of contact phaseinjuries due to the low friction of theice surface. The overuse injuries in thelower extremity usually show upmore proximally in the groin or lowback due to the inherent need forskate and skater to be moving in op-posite directions as propulsion occurs.Groin injuries in the adductor musclegroup (adductor magnus, longus andbrevis) occur when the thigh is exter-nally rotated and the hip is abducted,thus putting this muscle group undermaximal strain. Dr. Eric Babins fromthe University of Calgary has reporteda reduction in pain of the lumbarspine and lower extremity along withimproved performance with properfitting of skates, blade alignment andadjustment for leg length discrepan-cies as required due to the improvedbiomechanical balance above theskate blade.


NOVEMBER/DECEMBER 2003 • PODIATRY MANAGEMENTwww.podiatrym.com 55

Figure 6: Haglund’s deformity and counter expansion.

Ice Skating...

tive adhesive felt padding withinthe skates, or expansion of the heelcounter by a local skate shop. Awell-posted custom foot orthoticcan also decrease the movement ofthis prominence within the skate.The tight fit of skates can also in-crease the incidence of Morton’sneuroma and dorsal superficialcompression neuropathies.

Proper boot structure, alongwith the necessary biomechanics ofskating, can decrease the frequencyof complaints from certain patholo-gies. Hallux limitus, Achilles ten-donopathy and plantar fasciitis areall less commonly a problem dur-ing skating activities.

Biomechanical ly-producedoveruse foot and ankle clinical in-jury patterns can clearly be identi-fied in ice skating. The narrowblade or balance point creates needfor strenuous eccentric muscle con-trol and proprioceptive skills to as-sist in balance over this small bal-ance point. As a result, general footfatigue from strain of the small in-trinsic muscles of the foot are com-mon. As well as the intrinsic mus-cle strains, there are the extrinsictendonopathies that can occur inthe posterior tibial tendon and theperoneal tendons and muscles as areaction to the need for balance.

In comparison to other sportingactivities, power skating shows a de-crease in the number of contact phaseinjuries due to the low friction of theice surface. The overuse injuries in thelower extremity usually show upmore proximally in the groin or lowback due to the inherent need forskate and skater to be moving in op-posite directions as propulsion occurs.Groin injuries in the adductor musclegroup (adductor magnus, longus andbrevis) occur when the thigh is exter-nally rotated and the hip is abducted,thus putting this muscle group undermaximal strain. Dr. Eric Babins fromthe University of Calgary has reporteda reduction in pain of the lumbarspine and lower extremity along withimproved performance with properfitting of skates, blade alignment andadjustment for leg length discrepan-cies as required due to the improvedbiomechanical balance above theskate blade.



Figure 6: Haglund’s deformity and counter expansion.Figure 6: Haglund’s deformity and counter expansion

lower extremityand foot examneeds to be doneas would be donefor any athleticpopulation, and adecision on footorthotics can bemade using soundRoot biomechani-cal techniques.6

These techniquesof forefoot to rear-foot and rearfootto leg control willhelp to compensate for biomechan-ical faults, help stabilize the subta-lar and midtarsal joints, and helpmaintain sound structural align-

Clinical Biomechanical Balance There are two steps in the pro-

cess to assist a skater from a biome-chanical perspective. The first is thepositioning of the foot within theboot using standard podiatricbiomechanical principles. The sec-ond is the balance of the bladeonto the boot itself.

Step 1: Foot balance withinboot—custom foot orthotic.

A general podiatric clinician canbe confident when dealing with thefirst step of biomechanical control,which is positioning the foot prop-erly within the boot. A complete

ment of the lower extremity fromthe midtarsal joint to the hip, pro-viding a solid lever for propulsion.This orthotic can then be improvedupon by using a general under-standing of skating mechanics andapplying the newer techniques offoot orthotic control as discussedby Kirby and Blake.7,8

As a skater is in single-limb sup-port in the early stages of propul-sion, the foot is abducted and thehip externally rotated. The skateand skater are moving in oppositedirections at this time while tryingto balance on the narrow skateblade. As such, the center of gravityis much more medial with respectto the weight-bearing extremity,and even subtle biomechanicalfaults, causing excessive foot prona-tion, will cause a skater to spendtoo much time on the medial skateedge. Power and efficiency are cre-ated by staying on the outside edgeas long as possible early in the typi-cal skate cut. Therefore, maximallycontrolling the medial column ofthe foot with respect to the subtalarjoint axis location can greatly assista skater with this task. Using boththe newer and traditional biome-chanical controlling techniques im-proves skating power and balanceduring propulsion.

Orthotic Design For Skating1. Neutral suspension casts of feet. 2. Trace or send skate insoles

with casts to improve boot fit. 3. Intrinsic forefoot posting un-

less custom added-depth skateboots are used.

4. Standardly, invert casts 10degrees using Blake technique toincrease medial arch contact andto increase time spent on lateral

Ice Skating...



Figure 7: Skate Orthotic

About The American Academy ofPodiatric Sports Medicine

The American Academy of Podiatric Sports Medicine is thesecond largest affiliate of the American Podiatric Medical Associa-tion. Over 150 of its 500 plus members have achieved Fellowshipstatus in the AAPSM.

The AAPSM has a major goal of advancing the understanding,prevention and management of lower extremity sports and fit-ness injuries. The AAPSM believes that providing such knowledgeto the profession and to the public will optimize enjoyment andsafe participation in sports and fitness activities. The AAPSM ac-complishes this mission through professional education, scientificresearch, public awareness and membership support.

The AAPSM has long been the organization looked to by thepublic and media for authoritative information on all aspects ofpodiatric sports medicine. Members of the AAPSM have alldemonstrated significant interest in podiatric sports medicineand are sought out by athletic trainers, teams, and patients alikefor their expertise. In general, members of the AAPSM have ex-tremely busy practices and attract patients who are physically ac-tive and have a commitment to health and wellness.

One of the most popular sources the AAPSM has available isthe website (www.aapsm.org.), which offers information to thepodiatric profession as well as the general public. The most popu-lar section of the website is the AAPSM shoe evaluations. TheAAPSM evaluates over 100 shoes each year in over 15 categoriesand they are posted on the AAPSM website.

Any practicing podiatrist with an interest in sports medicineshould become a member of AAPSM. Join other AAPSM memberswho are dedicated to promoting the AAPSM mission statement aswell as demonstrating to their own patients that they have made acommitment to this practice specialty. If you are interested in be-coming a member, please contact Rita Yates, AAPSM Executive Di-rector, at [email protected] or call toll free at (888) 854-FEET.

For more information, circle #196 on the reader service card.

Figure 7: Skate Orthotic


blade edge. Increase as clinically justified. 5. Standardly, use a 3-4 mm medial heel skive

cast modification to help with lateral edge control.Increase as clinically justified.

6. Polypropylene shells are preferable as they canbe more easily modified as needed to the medial shankof the skate boot.

7. Extrinsic rearfoot posts work if well-skived to fitin the heel counter of boot and use a thin cap to de-crease heel lift. There should be no motion allowed for

in the rearfoot posting. 8. Use full-length extensions with thin top cover

materials of good friction next to the foot for grip and“feel.” A thin layer of firm Korex under the extensionwill decrease forefoot irritation from blade housingmounting rivets in the boot.

9. Some skaters like buttress or toe crest pads builtinto the extension for their toes to grip onto.

Step 2: Blade Balance The second step in mechanically helping skaters in-

volves blade balance. Blade balance is accomplishedusing three different techniques: sagittal plane rocker,medial-lateral position of blade, and varus/valgus wedg-ing of blade, which can incorporate limb lifts. These in-terventions are usually best performed by a professionalskate mechanic after podiatric advice is given.

The sagittal plane rocker of the blade allows for easy re-sponse to the center of gravity changes in the sagittal plane.Standardly, the rocker is in the centre of the blade with onlyone inch of the blade in contact with the ice. Some skaterswill increase their rocker (decrease contact with ice) in order

Ice Skating...


Figure 8: Sagittal plane rocker.Figure 8: Sagittal plane rocker

The tight fit of skates can increase the incidence of Morton’s neuroma and dorsal

superficial compression neuropathies.


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BiOmeCHANiCS

from blade housing mounting rivets in the boot. 9) Some skaters like buttress or toe crest pads built into the extension for their toes to grip onto.

Step 2: Blade Balance The second step in mechanical-ly helping skaters involves blade bal-ance. Blade balance is accomplished using three different techniques: sagittal plane rocker, medial-lateral position of blade, and varus/valgus wedging of blade, which can incorporate limb lifts. These interventions are usually best performed by a professional skate me-chanic after podiatric advice is given. The sagittal plane rocker of the blade allows for easy response to the center of gravity changes in the sagittal plane. Standardly, the rocker is in the center of the blade with only one inch of the blade in contact with the ice. Some skaters will increase their rocker (decrease contact with ice) in order to improve their maneuverability. Others will decrease their rocker to allow more blade to contact the ice and this will increase speed but decrease turning capabilities. Adjustments of rockers are more a matter of individual preference for performance, and should only be done in the hands of a skilled skate technician (Figure 8). The medial-lateral position of the blade on the boot has a significant ef-fect on a skater’s posture and balance. The standard blade placement is lon-

the outside edge as long as possible early in the typical skate cut. There-fore, maximally controlling the me-dial column of the foot with respect to the subtalar joint axis location can greatly assist a skater with this task. Using both the newer and traditional biomechanical controlling techniques improves skating power and balance during propulsion.

Orthotic Design for Skating (Figure 7) 1) Neutral suspension casts of feet. 2) Trace or send skate insoles with casts to improve boot fit. 3) Intrinsic forefoot posting unless custom added-depth skate boots are used. 4) Standardly, invert casts 10 de-grees using Blake technique to increase medial arch contact and to increase

time spent on lateral blade edge. In-crease as clinically justified. 5) Standardly, use a 3-4 mm me-dial heel skive cast modification to help with lateral edge control. In-crease as clinically justified. 6) Polypropylene shells are pref-erable as they can be more easily modified as needed to the medial shank of the skate boot. 7) Extrinsic rearfoot posts work if well-skived to fit in the heel counter of boot and use a thin cap to decrease heel lift. There should be no motion allowed for in the rearfoot posting. 8) Use full-length extensions with thin top cover materials of good friction next to the foot for grip and “feel.” A thin layer of firm Korex under the ex-tension will decrease forefoot irritation



individual preference for performance,and should only be done in the handsof a skilled skate technician.

The medial-lateral position of theblade on the boot has a significant ef-fect on a skater’s posture and bal-ance. The standard blade placementis longitudinally from heel center tothe second metatarsal head, and sec-ond digit. This blade position shouldprovide an inherently stable platformfor the foot to sit with pure sagittalplane rocking.

A medially deviatedsubtalar joint axis will in-fluence the default contactportion of the standardlyplaced blade. Shifting theblade medially will placethe default contact portionof the blade in a morefunctional position with re-spect to the medially devi-ated axis in those patients.See figure 11 and 12. In ex-tremely rigid inverted feet,moving the blade laterallyon the boot will help to

improve balance.Balancing the blade

with wedging is thefinal blade adjust-ment technique. Afteran appropriate orthot-ic has been made, therocker has beenchecked, the bladehas been moved me-dially or laterally asneeded, a decision onusing a wedge can bemade by looking atthe position of theblade edges with respect to the

to improve their maneuverability.Others will decrease their rocker toallow more blade to contact the iceand this will increase speed but de-crease turning capabilities. Adjust-ments of rockers are more a matter of

weight-bearing surface. A wedge canassist in balancing the blade to theboot and upper body so that in staticstance each edge of the blade bal-ances on the ice surface equally. Asodd as it may seem, a supinated orvarus foot can require a medialwedge to bring the medial blade edgeevenly to the ground. A pronated orvalgus foot can require a lateralwedge to bring the lateral blade edgeto the ground. (See figures 13 to 15.)

The podiatric management of theskater can be best shown through aseries of case examples. Each of thesescenarios depicts the management ofincreasingly complex cases involvingboth foot-to-boot balance and blade-to-boot balancing techniques.

Ice Skating...



Figure 9: Standard blade placement.

Figure 13: No wedge needed.

Figure 14: Supinated or lower extremity varum-medial wedge.

Figure 12: Shifting the blade medially willput it in a more functional position.

Figure 11: Standard blade placementcompared to STJ axis.

Figure 15: Pronated or lower extremity valgum-lateral wedge.

Figure 10: Standard blade placement, poste-rior view.

Figure 9: Standard blade placement Figure 10: Standard blade placement, posterior view









Ice Skating...










Figure 11: Standard blade placement compared to STJ axis









Ice Skating...










Figure 12: Shifting the blade medially will put it in a more functional position









Ice Skating...










Figure 13: No wedge needed









Ice Skating...










Balancing the blade with wedging is the final blade adjustment technique.


BiOmeCHANiCS

gitudinally from heel center to the second metatarsal head, and second digit (Figures 9, 10). This blade position should provide an inherently stable platform for the foot to sit with pure sagittal plane rocking. A medially deviated subtalar joint axis will influence the default contact portion of the standardly placed blade. Shift-ing the blade medially will place the default contact portion of the blade in a more functional position with respect to the medially deviated axis in those patients (Figures 11, 12). In extremely rigid inverted feet, moving the blade laterally on the boot will help to improve balance.

Balancing the blade with wedging is the final blade ad-justment technique. After an appropriate orthotic has been made, the rocker has been checked, the blade has been moved medially or laterally as needed, a decision on using a wedge can be made by looking at the position of the blade edges with respect to the weight-bearing surface. A wedge can assist in balancing the blade to the boot and upper body so that in static stance each edge of the blade balances on the ice surface equally. As odd as it may seem, a supinated or varus foot can require a medial wedge to bring the medial blade edge evenly to the ground. A pronated or valgus foot can require a lateral wedge to bring the lateral blade edge to the ground (Figures 13, 14, 15).











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Figure 14: Supinated or lower extremity varum-medial wedge









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Figure 15: Pronated or lower extremity valgum-lateral wedge


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balance problems. History and phys-ical exam finds him otherwise fit and healthy. A diagnosis of peroneal ten-donitis was made due to a rigid forefoot valgus and a limb-length discrepancy (Figures 23, 24). The mechanical solution to this pa-tient’s problem was a custom-made, added-depth skate boot to accommo-date an orthotic with an extrinsic fore-foot valgus post to the sulcus. Stan-

The podiatric management of the skater can be best shown through a series of case examples. Each of these scenarios depicts the management of increasingly complex cases involving both foot-to-boot balance and blade-to-boot balancing techniques.

Case #1—Moderate Pronation Ten-year-old white male suffers from medial arch and heel pain pre-dominantly in his day-to-day activities, which carries over into his recre-ational hockey. He is otherwise fit and healthy and has been diag-nosed with plantar fasciitis. A complete podiatric biome-chanical exam was performed and the pertinent results were a two-degree forefoot varus and a four-degree forefoot supinatus bi-laterally (Figures 16, 17, 18). The first goal in treatment was a daily orthotic to relieve his symptoms and the secondary goal was a skating-specific orthotic to improve his skating performance

and his enjoyment of his recreation. The polypropylene skating orthotic was made from a neutral suspension cast with reduction of the supinatus. The casts were modified with 10 de-grees of inversion and a 3 mm. medial heel skive. The forefoot was posted in-trinsically 2° varus after the inversion cast modification, and a rearfoot post was added to balance the orthotic. A functional skate orthotic with maximal control was used to assist this patient, along with a good-quality and well-fit-ted skate boot. No blade adjustments were needed, and the blade was left in its standard default position.

Case #2—Moderate-Severe Pronation Twelve-year-old male suffers from medial ankle and knee pain while play-ing hockey. He is otherwise fit and healthy. After a complete history and physical examination, a diagnosis of

posterior tibial tendon strain and patellofem-oral pain syndrome was made. The pri-mary etiology of his problems was deemed to be biomechanically produced from exces-sive foot pronation. He functions maxi-mally pronated due to a fully compensated forefoot and rearfoot varus deformity bilat-

erally of approximately four degrees for both (Figure 19). A custom foot orthotic was manufactured from casts corrected to 25° of inversion using the Blake inversion technique and a 4 mm. medial heel skive was added. The forefoot to rearfoot was posted a further 4° of varus and a balancing post was placed on the rearfoot also in 4° of varus. A further me-chanical intervention was needed and the blades were moved medially on the skates (Figures 20, 21, 22). The final solution for this patient was a good quality skate boot appropri-ately fitted, an aggressive custom foot or-thotic and a blade balancing adjustment.

Case #3—Supinated Pes Cavus Foot Type An 18-year-old Western Canadian Hockey League player suffers from lat-eral leg and ankle pain, as well as skate




The first goal in treat-ment was a daily orthot-ic to relieve his symp-toms and the secondarygoal was a skating-specif-ic orthotic to improvehis skating performanceand his enjoyment of hisrecreation. Thepolypropylene skatingorthotic was made froma neutral suspension castwith reduction of thesupinatus. The casts were modified

Case #1—Moderate Pronation Ten year old white male suffers

from medial arch and heel painpredominantly in his day-to-dayactivities, which carries over intohis recreational hockey. He is other-wise fit and healthy and has beendiagnosed with plantar fasciitis.

A complete podiatric biomechani-cal exam was performed and the per-tinent results were a two degree fore-foot varus and a four degree forefootsupinatus bilaterally.

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Figure 16: Case #1, Moderate pronation.

Figure 17: Case #1, moderate pronation. Figure 18: Case #1, moderate pronation.Figure 17: Case #1, moderate pronation






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Figure 17: Case #1, moderate pronation. Figure 18: Case #1, moderate pronation.






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Figure 17: Case #1, moderate pronation. Figure 18: Case #1, moderate pronation.

Figure 16: Case #1, Moderate pronation






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Figure 17: Case #1, moderate pronation. Figure 18: Case #1, moderate pronation.Figure 18: Case #1, moderate pronation

Many blade adjustments were needed to assist in this patient’s performance.


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Conclusion Ice skating, and more specifically power skating, is showing increased popularity throughout North Amer-ica. All podiatric practitioners can expect to see ice skaters in their of-

dard Root biomechanical principles were used to make this orthotic and no newer inversion techniques were utilized (Figure 25). Many blade adjustments were

needed to assist in this patient’s per-formance. A limb-lift was added full-length, the blades were moved laterally on the boots and a medial wedge was inserted to assist further in bringing the medial edge of the skate blade down to the ground (Figures 26, 27, 28).



the orthotic. A functional skate or-thotic with maximal control wasused to assist this patient, along witha good-quality and well-fitted skateboot. No blade adjustments wereneeded, and the blade was left in itsstandard default position.

with 10 degrees of inversion, and a 3mm. medial heel skive. The forefootwas posted intrinsically 2° varus afterthe inversion cast modification, anda rearfoot post was added to balance

Case #2—Moderate-SeverePronation

Twelve year old male suffersfrom medial ankle and knee painwhile playing hockey. He is other-

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Figure 19: Case #2, Moderate-severe pronation.

Figure 20: Case #2, skate orthotic.

Figure 21: Case #2, blade adjustment.

Figure 22: Case # 2, end results.

Figure 19: Case #2, Moderate-severe pronation





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Figure 21: Case #2, blade adjustment





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Figure 20: Case #2, skate orthotic





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Figure 22: Case # 2, end results.Figure 22: Case #2, end results





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wise fit and healthy. After a complete history andphysical examination, a diagnosis of posterior tibialtendon strain and patellofemoral pain syndrome wasmade. The primary etiology of his problems wasdeemed to be biomechanically produced from exces-sive foot pronation. He functions maximally pronateddue to a fully compensated forefoot and rearfoot varusdeformity bilaterally of approximately four degrees forboth.

A custom foot orthotic was manufactured fromcasts corrected to 25° of inversion using the Blake in-version technique and a 4 mm. medial heel skive wasadded. The forefoot to rearfoot was posted a further 4°of varus and a balancing post was placed on the rear-foot also in 4° of varus. A further mechanical interven-tion was needed and the blades were moved medially

on the skates.The final solu-

t ion for this pa-t ient was a goodquality skate bootappropriately fit-ted, an aggressivecustom foot or-thotic and a bladebalancing adjust-ment.

Case #3—Supinated PesCavus Foot Type

An 18 year oldWestern Canadian

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Figure 23: Case 3, forefoot valgus. Continued on page 62

Figure 24: Case 3, neutral cast.


Figure 23: Case #3, forefoot valgus


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91(9): 465-487, 2001. 9 Blake RL: Inverted functional ortho-sis. JAPMA 76: 275, 1986.

fices. Podiatric biomechanical man-agement using both traditional and newer techniques used in other ath-letic populations can be modified to work in the athletic skating popula-tion. The sound use of biomechan-

ical intervention can assist in the pleasure and performance of this unique activity. PM

Bibliography 1 Roy B: Biomechanically features of different starting positions and skating strides in ice hockey. In Asmussen E, Jor-genson K (eds): Biomechanics V1-B. Balti-more, University Park Press, 1978, p. 137. 2 Hoshizaki TB, Kirchner GJ: A com-parison of the kinematic patterns between supported and non-supported ankles during the acceleration phase of forward skating. Proceedings of the International Symposium of Biomechanics in Sport, 1987. 3 Marino GW: Acceleration time re-lationships in an ice skating start. Res Q 50:55, 1979. 4 Mueller M: Kinematics of speed

skating. Master’s thesis, Universi-ty of Wisconsin, 1972. 5 Marino GW, Weese RG: A ki-nematic analysis of the ice skating stride. In Terauds J,

Gros HJ (eds): Sci-ence in Skiing, Skat-ing and Hockey. Del Mar, California, Ac-ademic Publishers, 1979, pp. 65, 73. 6 “Objective assessment of cus-tom-made orthoses benefit in improving balance among figure ice-skaters” Rachel Baisch, Gurtej Grewal, Stephanie Wu, Beth Jarrett, Neil Humble, Bijan Najafi. Footwear Science. Volume 5; issue sup 1 pp. s126-s127 July 9, 2013. 7 Root ML, Orien WP, Weed JH, Hughes RJ: Biomechanical Examination of the Foot Volume 1. Clinical Biomechanics Corporation. Los Angeles, CA. 8 Kirby KA: Subtalar Joint Axis Loca-tion and Rotational Equilibrium Theory of Foot Function. J AM Podiatr Med Assoc


Dr. Humble is Clinical Assistant Professor, Department of Surgery at the University of Calgary and Assistant Professor, Faculty of Kinesiology at the Uni-versity of Calgary.








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Figure 24: Case #3, neutral cast








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Figure 25: Case #3, skate orthotic. Figure 25: Case #3, skate orthotic


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Dr. Humble is ClinicalAssistant Professor,Department of Surgeryat the University ofCalgary and AssistantProfessor, Faculty ofKinesiology at the Uni-versity of Calgary. He isa Fellow of The Ameri-can Academy of Podi-atric Sports Medicineand of The AmericanCollege of Foot andAnkle Surgeons

Figure 26: Case #3, heel lift.

Figure 27: Case #3, blade placement.

Figure 28: Case #3, medial wedge to balance.

Figure 26: Case #3, heel lift


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Figure 28: Case #3, medial wedge to balance.

Figure 27: Case #3, blade placement


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Figure 28: Case #3, medial wedge to balance.Figure 28: Case #3, medial wedge to balance

All podiatric practitioners can expect to see ice skaters in their offices.

Living on the Edge: The Biomechanics of Power Skatingcenter of gravity move in an opposite direction...

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