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©BIKEFIT.com

Foot Anatomy & Foot-Pedal

Interface

Clint Laird, DPMFAAPSM, FACFAS

Reaction Sports Medicine,

Director.

Medicine of Cycling

Medicine of Cycling

Lower Extremity Anatomy Review:

Normal Anatomy

Abnormal Anatomy

Orthotic Devices

Shoe/Pedal Interface:

5 Cleat Adjustments

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Normal Anatomy

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Bones of the foot

26 normally occurring

40 accessory ossiclesof the foot

33 joints

106 ligaments

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Anterior Tendons of the Leg

Tibialis Anterior

Extensor HallucisLongus

Extensor DigitorumLongus

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Lateral Tendons of the Leg

Peroneus Longus

Peroneus Brevis

Peroneus Tertius*

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Medial Leg Tendons

Tibialis Posterior

Flexor HallucisLongus

Flexor DigitorumLongus

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Posterior Leg Tendons

Achilles Tendon (medial and lateral heads of the gastrocnemius and the soleus)

Plantaris

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Nerves of the Foot

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Abnormal Anatomy

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Tendonopathies

Tibialis Anterior Tendonitis

Shoe gear irritation

Direct trauma

Compartment syndrome (rare)

Saddle too high

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Tendonopathies

Posterior TibialTendonitis

Flat foot

Age

Running/Triathletes

Saddle too low

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Tendonopathies

Peroneal Tendonitis

Rear foot varus

Saddle too high

Ankle sprain

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Neuroma

Inflammation of the insulation around a nerve.

Causes: biomechanical, trauma, improper shoegear and repeated stress.

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Neuroma

Typically between 3rd

and 4th metatarsal heads (Morton’s Neuroma).

Can be between any of the metatarsal heads.

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Neuroma

Heuter’s Neuroma- 1st

and 2nd webspace

Hauser’s Neuroma-2nd & 3rd

Morton’s Neuroma-3rd & 4th

Islen’s Neuroma- 4th

& 5th

Joplin’s- medial hallux

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Neuroma affects Webspace

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Nerve Compression

Deep Peroneal Nerve

High Arched foot type

Low volume shoes

Overtightening shoes

Spurring at the 2nd

Metatarsal-Cuneiform joint (common).

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Varus Definition

Position of the rearfoot or the forefoot relative to the weight-bearing surface that is inverted.

Towards the midline of the body.

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Valgus Definition

Position of the rearfoot or the forefoot relative to the weight-bearing surface that is everted.

Away from the midline of the body

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Rearfoot Varus vs. Valgus

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Forefoot Varus & Valgus

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Cycling orthotics

Must be thin (2mm suborthalon or carbon fiber)

Allow for minimal correction due to depth of shoes.

Minimal rearfootcontrol and forefoot correction.

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Is there a need for custom?

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The Question…

What is the BESTfoot

position for a

cyclist?25

The Answer…

The BEST foot position creates…

MAXIMAL biomechanical efficiency for lower extremity joints/tissue

while

MINIMIZING risk of injury…

for that SPECIFIC CYCLIST26

4% Less than 10% of people/cyclists have a neutral foot

(Cornwall, 2000; Agosta 2001; Whitney, 2003)

Break-down (Garbolosa et al., 1994)

87% = FF varus 9% = FF valgus

Plantar flexed first ray? 4% = Neutral FF:RF relationship

Plantar flexed first ray?

Pedals are made for flat-footed connection. (Millslagle et al., 2004)

Therefore, conventional pedals only “fit” 4% of the cycling population. (Millslagle et al., 2004)

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Leg Architecture: Everyone is UNIQUE!

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What is “normal?”What is “efficient?”

Inefficient Efficient30

©©

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Peak Force = Ball of Big Toe(Sanderson & Cavanaugh, 1987)

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Cleat Fore-Aft Range

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Methods: Cleat Fore-Aft

Primary Goal Ball of big toe over or slightly in front of the

pedal spindle for MAXIMAL FORCE TRANSFER

↑ Stiffness = ↑ Fore-Aft Range

Move cleat Foot FORWARD (anterior) = Cleat BACK Foot BACK (posterior) = Cleat FORWARD

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Setting up front view

Reference Points Second toe (2nd ray) Tibial tuberosity

Lasers – self leveling One for each leg

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Medial-lateral cleat position

What would you change? WHY?38

Methods: Cleat/Foot Medial-Lateral

Primary Goal: Bring foot under knee

Move cleat Foot OUT = Cleat IN Foot IN = Cleat OUT

(Boyd, Neptune, Hull, 1997; Ruby & Hull, 1993)39

Side-to-Side

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Cleat Medial = Foot Lateral Cleat Lateral = Foot Medial

1/2”

1/8” Longer Spindle

1/4” Longer

1mm Washer & 20mm Spacer &/Or Multiple Spindle Lengths

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Pedal Brands Speedplay®

5 widths

Keywin®

6 widths

Shimano®

2 widths

Lateral Knee: Before & After

AfterBefore42

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V-twin Before Spacer & After Spacer

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Valgus Forces&

Cycling

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Causes of Excessive Valgus Forces

Morphological Structure of the cyclist

Neuromuscular PMH

Bike & Foot-Pedal Interface

***Genetics!***

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Solutions: Excessive Valgus Forces

External/Foot-Pedal Interface OTC shoe inserts Custom orthotics Wedges

Cleat Wedges ITS (In The Shoe) Fore Foot & Rear Foot

Internal/Body HEP Manual RX Etc…

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Effects of Severe Valgus Forces (Ruby, Hull, Kirby, Jenkins 1992; Sanner & O’Halloran, 2000; Powers, 2012)

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Forefoot Varus: BikeFit Recommendations

Correcting for FF Varus** 0-2°

No Wedges

3-7° 1 Wedge

6-12° Up to 2 Wedges

12-20° Up to 3 Wedges

** Static Measurements

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Research demonstrates…

Use of cleat wedges increases power output. (Moran & McGlinn, 1995, Dinsdale & Williams, 2010)

Use of cleat wedges improves efficiency.(Sinéad FitzGibbon, doctoral candidate, RMUoHP Ph.D Orthopedics and Sports Physical Therapy).

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MFPI vs. BikeFit®

Recommendations

Modified Foot Posture Index

MILD 0-7 degrees

MODERATE 8-14 degrees

STRONG X > 15 degrees

“WHOPPING” ** 20+ degrees

BikeFit® Recommendations 0-2°

No Wedges

3-7° 1 Wedge

6-12° Up to 2 Wedges

12-20° Up to 3 Wedges

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Pressure area with & without varus wedge

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Posterior View

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Tiberio, 1998

Valgus Forces: Before & After

AfterBefore54

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Cycling: Minimal Variation

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Rigid

Neutral/Flat

Custom or Accommodative Inserts?

Primary Goals: Force redistribution Capture the midtarsals

Custom Orthotics: CYCLING

Cycling orthotics RUNNING

Running orthotics

Accommodative: MAJORITY of cyclists SuperFeet® Heat Moldable

“semi-custom”

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Rotation vs Float(Ruby & Hull, 1993; Wolchok, Hull, Howell, 1998)

Primary Goal: Reduce frictional torsion between tibia & femur

Float = motion of the cleat in the pedal

Rotation = position of the cleat

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Cleat Rotation

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Rotational Adjustment

TOE-OUT Rotate front of cleat IN

EX: Tibial External Torsion

TOE-IN Rotate front of cleat

OUT EX: Tibial Internal

Torsion

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STRAIGHT TOED-OUT

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“Heel IN”

Ideal Cleat Position

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Leg Length Differences

Structural Measurable difference between length of

R & L femurs &/or tibias

Functional Lumbar spine/pelvic obliquity rotation

Asymmetry: COMMON

Symmetry: UNCOMMON

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Leg Length Difference ?

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LLD or Pelvic Obliquity?

How does this affect the legs?

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LLD or Pelvic Obliquity?

How does this affect the legs? Right knee tracks

MEDIALLY (BDS)

Left knee tracks LATERALLY (TUS)

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Standing AP X-Ray

L > R Structural LLD

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Gold Standard: Standing Scanogram

Full-length x-ray Feet Lumbar Spine

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(Jackson & Porter 2012)

Standing AP X-ray

“…& the MD cried…

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Leg Length Difference

Verify presence of a STRUCTURAL LLD

Start correction at 25-50% LLD: x > 12 mm…

Correction up to within 5 mm of total LLD

Sole lift, LL shim cycling & daily shoes

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When Do We Stop?

STOP WHEN...

Your level of knowledge has been met.

Noted improvement in efficiency of cyclist yet discomfort/pain still present.

You’re little voice tells you to...

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Clinical Differential Diagnosis (Two Classic Cycling “Pains”)

Medial knee pain

Numbness in ball of foot

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Clinical Differential Diagnosis (Two Classic Cycling “Pains”)

Medial knee pain Patello-femoral pain Medial meniscal pathology Knee arthritis (OA)

Knee joint Patella

Hip arthritis (OA) Referred pain

Numbness in ball of foot Metatarsalgia Neuroma Low back injury at nerve root

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Clinicians & Bike Fitters

Advocacy creates allies.

Referring out bolsters your credibility.

There is always more to learn.

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Thank You!

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References cont. Carpes FP, Dagnese F, Kleinpaul JF, Martins-Ede A, Mota CB. Effects of

workload on seat pressure while cycling with two different saddles.

Chmielewski TL, Hodges MJ, Horodyski M, Bishop MD, Conrad BP, Tillman SM. Investigation of clinician agreement in evaluating movement quality during unilateral lower extremity functional tasks: a comparison of 2 rating methods. JOPST. 2007; 37 (3): 122-129.

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Cobb SC, Tis LL, Johnson JT. The effect of 6 weks of custom-molded foot orthosis intervention of postural stability in partifpants with x > 7 degrees of forefoot varus. Clinical Journl of Sports Medicine. 2006: 16: 316-322.

Cook CE, Hegedus EJ. Orthopedic physical examination tests: an evidence-based approach. Upper Saddle River, New Jersey. Pearson Prentic Hall; 2008.

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References cont.

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Cornwall MW. Common pathomechanics of the foot. Journal of Athletic Therapy Today. 2000; 5: 10-16. Cummings G, Scholz JP, Barnes K. The effect of imposed leg length difference on pelvic bone symmetry.

Spine. 1993; 18 (3): 368-73.

Dinsdale NJ, Williams AG. Can forefoot varus wedges enhance anaerobic cycling performance in untrained males with forefoot varus? Journal of Sport Scientific and Practical Aspects. 2012. 7: 5-10.

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Friedberg O. Clinical Symptoms and biomechanics of lumbar spine and hip joint in leg length inequality. Spine. 1983; 8 (6): 643-651.

Garbalosa JC, McClure MH, Catlin PA, Wooden M. The frontal plane relationship of the forefoot to rearfoot in an asymptomatic population. Journal of Orthopedic and Sports Physical Therapy. 1994: 20: 20-26.

Gregor RJ, Wheler JB. Biomechanical factors associated with shoe/pedal interfaces. Sports Medicine. 1994; 17: 117-131.

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Jackson R, Porter K. The Pelvis and Sacroiliac Joint: Physical Therapy Patient Management Utilizing Current Evidence (Independent Study Course 21.2.5) In: Current Concepts of Orthopedic Physical Therapy. 3rd Ed. 2011: 1-60.

References cont. Krawiec CJ, Denegar CR, Hertel J, Salvaterra GF, Buckley WE. Static

innominate asymmetry and leg length discrepancy in asymptomatic collegiate athletes. Manual Therapy. 2003. 8(4): 207-213.

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Moran GT, McGlinn GH. The effect of variations in the foot pedal interface on the efficiency of cycling as measure by aerobic energy cost and anaerobic power. Biomechanics in Sport. 1995; 12: 105-109.

Norkin C.C & Levangie P.Kjoint structure & function: a comprehensive analysis. Philadephia, PA. F.A. Davis; 1992.

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Powers CM. The influence of abnormal hip mechanics on knee injury: a biomechanical perspective. JOSPT. 2010; 40 (2): 42-50.

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References cont.

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Ruby P, Hull ML, Kirby KA, Jenkins DW. The effect of lower-limb anatomy on knee loads during seated cycling. Journal of Biomechanics. 1992; 25: 1195-1207.

Ruby P, Hull ML. Response of intersegmental knee loads to foot/pedal platform degrees of freedom in cycling. Journal of Biomechanics. 1993; 26: 1327-1340.

Salai M, Brosh T, Blankenstein A, Oran A, Chechik A Effect of changing the saddle angle on the incidence of low back pain in recreational cyclists. British Journal of Sports Medicine. 1999; 33(6): 398-400.

Sanderson, D.J., Cavanaugh P.R. An investigation of the in-shoe pressure distribution during cycling in conventional cycling shoes or running shoes. In Jonsson (Ed) Biomechanics XB, 903-907. Human Kinetics Publishers, Champaign; 1987.

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References cont.

Schamberger W. The Malalignment Syndrome: Implications for Medicine and Sport. New York, New York. Chruchill Livingstone; 2002.

Vleeming A, Van Wingerden JP, Sniders CJ, Stoeckare R, Stijnen T. Load application to the sacrotuberous ligament; influences on sacroiliac joint mechanics. Clinical Biomechanics, 1989; 4 (4): 204-209.

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Wolchok JC, Hull ML, Howell, SM. The effect of intersegmental knee moments on patellofemoral contact mechanics in cycling. Journal of Biomechanics. 1998; 31: 677-683.

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