Medicine of Cycling
Foot Anatomy & Foot-Pedal Interface
Medicine of Cycling Clint Laird, DPM
Lower Extremity Anatomy Review: Normal Anatomy Abnormal Anatomy Orthotic Devices
Shoe/Pedal Interface: 5 Cleat Adjustments
FAAPSM, FACFAS Reaction Sports Medicine, Director. ©BIKEFIT.com
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Normal Anatomy
Bones of the foot
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Anterior Tendons of the Leg
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26 normally occurring 40 accessory ossicles of the foot 33 joints 106 ligaments
Lateral Tendons of the Leg
Tibialis Anterior Extensor Hallucis Longus Extensor Digitorum Longus
Peroneus Longus Peroneus Brevis Peroneus Tertius*
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Medial Leg Tendons
Posterior Leg Tendons
Tibialis Posterior Flexor Hallucis Longus Flexor Digitorum Longus
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Nerves of the Foot
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Abnormal Anatomy
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Tendonopathies
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Achilles Tendon (medial and lateral heads of the gastrocnemius and the soleus) Plantaris
Tendonopathies
Tibialis Anterior Tendonitis Shoe gear irritation Direct trauma Compartment syndrome (rare) Saddle too high
Posterior Tibial Tendonitis Flat foot Age Running/Triathletes Saddle too low
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Tendonopathies
Neuroma
Peroneal Tendonitis Rear foot varus Saddle too high Ankle sprain
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Neuroma
Neuroma
Typically between 3rd and 4th metatarsal heads (Morton’s Neuroma). Can be between any of the metatarsal heads.
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Heuter’s Neuroma- 1st and 2nd webspace Hauser’s Neuroma2nd & 3rd Morton’s Neuroma3rd & 4th Islen’s Neuroma- 4th & 5th Joplin’s- medial hallux
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Neuroma affects Webspace
Nerve Compression
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Inflammation of the insulation around a nerve. Causes: biomechanical, trauma, improper shoegear and repeated stress.
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
Valgus 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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Rearfoot Varus vs. Valgus
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Forefoot Varus & Valgus
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Cycling orthotics
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Position of the rearfoot or the forefoot relative to the weight-bearing surface that is everted. Away from the midline of the body
Is there a need for custom?
Must be thin (2mm suborthalon or carbon fiber) Allow for minimal correction due to depth of shoes. Minimal rearfoot control and forefoot correction.
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The Question…
The Answer… The BEST foot position creates…
What is the BEST foot position for a cyclist? 25
MAXIMAL biomechanical efficiency for lower extremity joints/tissue while MINIMIZING risk of injury… for that SPECIFIC CYCLIST 26
Leg Architecture: Everyone is UNIQUE!
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
4% = Neutral FF:RF relationship
Plantar flexed first ray? Plantar flexed first ray?
Pedals are made for flat-footed connection. (Millslagle et al., 2004)
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Therefore, conventional pedals only “fit” 4% of the cycling population. (Millslagle et al., 2004) 28
What is “normal?” What is “efficient?” ©
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Inefficient
©
Efficient
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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
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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
Medial-lateral cleat position
What would you change? WHY? 38
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Methods: Cleat/Foot MedialLateral
Primary Goal:
Side-to-Side
Bring foot under knee
Move cleat
Foot OUT = Cleat IN Foot IN = Cleat OUT Cleat Medial = Foot Lateral (Boyd, Neptune, Hull, 1997; Ruby & Hull, 1993)
Cleat Lateral = Foot Medial
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1mm Washer & 20mm Spacer &/Or Multiple Spindle Lengths
Lateral Knee: Before & After
1/8” Longer Spindle
Pedal Brands
Speedplay®
Keywin®
Shimano®
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1/4” Longer
5 widths 6 widths 2 widths
1/2”
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Before
After
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V-twin Before Spacer & After Spacer
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Causes of Excessive Valgus Forces
Valgus Forces & Cycling
Morphological
Neuromuscular
Structure of the cyclist
PMH
Bike & Foot-Pedal Interface ***Genetics!***
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Solutions: Excessive Valgus Forces
Effects of Severe Valgus Forces (Ruby, Hull, Kirby, Jenkins 1992; Sanner & O’Halloran, 2000; Powers, 2012)
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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Forefoot Varus: BikeFit Recommendations
Research demonstrates…
Correcting for FF Varus**
Use of cleat wedges increases power output. (Moran & McGlinn, 1995, Dinsdale & Williams, 2010)
Use of cleat wedges improves efficiency.
No Wedges
3-7°
6-12°
0-2°
1 Wedge
(Sinéad FitzGibbon, doctoral candidate, RMUoHP Ph.D Orthopedics and Sports Physical Therapy).
Up to 2 Wedges
12-20°
Up to 3 Wedges
** Static Measurements
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MFPI vs. BikeFit® Recommendations Modified Foot Posture Index
MILD
Pressure area with & without varus wedge
BikeFit® Recommendations
0-7 degrees
0-2°
No Wedges
MODERATE
STRONG
8-14 degrees
X > 15 degrees
“WHOPPING” ** 20+ degrees
3-7°
6-12°
1 Wedge
Up to 2 Wedges
12-20°
Up to 3 Wedges
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Valgus Forces: Before & After
Posterior View
Tiberio, 1998 54
Before
After
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Cycling: Minimal Variation
Custom or Accommodative Inserts?
Rigid
Primary Goals:
Neutral/Flat
Force redistribution Capture the midtarsals
Custom Orthotics:
CYCLING
RUNNING
Running orthotics
Accommodative:
MAJORITY of cyclists SuperFeet® Heat Moldable
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Cycling orthotics
“semi-custom”
(Razeghi & Batt, 2000; Sanner & O’Halloran, 2000; Cobb 2006)
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Rotation vs Float (Ruby & Hull, 1993; Wolchok, Hull, Howell, 1998)
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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
Rotational Adjustment
TOE-OUT
Rotate front of cleat IN
TOE-IN
Rotate front of cleat OUT
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EX: Tibial External Torsion
EX: Tibial Internal Torsion
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STRAIGHT
Ideal Cleat Position
TOED-OUT
“Heel IN” 61
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Leg Length Differences
Structural
Measurable difference between length of R & L femurs &/or tibias
Functional
Lumbar spine/pelvic obliquity rotation
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Leg Length Difference ?
LLD or Pelvic Obliquity?
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Asymmetry: COMMON Symmetry: UNCOMMON
How does this affect the legs?
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Standing AP X-Ray
LLD or Pelvic Obliquity?
How does this affect the legs?
Right knee tracks MEDIALLY (BDS) Left knee tracks LATERALLY (TUS)
L > R Structural LLD 67
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Gold Standard: Standing Scanogram
Standing AP X-ray
“…& the MD cried… Full-length x-ray Feet Lumbar Spine
(Jackson & Porter 2012)
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Leg Length Difference
Verify presence of a STRUCTURAL LLD
Start correction at 25-50%
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...
Correction up to within 5 mm of total LLD
Sole lift, LL shim
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STOP WHEN...
LLD: x > 12 mm…
When Do We Stop?
cycling & daily shoes
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Clinical Differential Diagnosis
Clinical Differential Diagnosis
(Two Classic Cycling “Pains”)
(Two Classic Cycling “Pains”)
Medial knee pain
Medial knee pain
Patello-femoral pain Medial meniscal pathology Knee arthritis (OA)
Hip arthritis (OA)
Knee joint Patella Referred pain
Numbness in ball of foot
Numbness in ball of foot
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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
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Al-Eisa E, Egan D, Deluzio K, Wassersug R. Effects of pelvic asymmetry and low back pain on trunk kinematics during sitting: a comparison with standing. Spine. 2006. 31(5): E135-43.
Badii M, Shin S, Torreggiani WC, Jankovic B, Gustofson P, Munk PL, Esdaile JM. Pelvic bone asymmetry in 323 study participants receiving abdominal CT scans. Spine. 2003. 28(12): 1335-1339.
Boyd, TF, Neptune RR, Hull ML. Pedal and knee loads using a multi-degree-offreedom pedal platform in cycling. Journal of Biomechanics. 1997; 30: 505-511.
Burke E. Proper fit of the bicycle. Clinics in Sports Medicine. 1994; 13: 1-14.
Burnett AF, Cornelius MW, Dankaerts W, O’Sullivan PB. Spinal kinematics and trunk muscle activity in cyclists: a comparison between healthy controls and non-specific chronic low back pain subjects-a pilot investigation. Manual Therapy. 2004; 9(4): 211219.
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References cont.
Bressel E, Larson BJ. Bicycle seat designs and their effect on pelvic angle, trunk angle, and comfort. Medicine and Science in Sports and Exercise. 2003; 35(2): 327332.
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.
Cibulka MT, Sinacore DR, Cromer GS, Delitto A. Unilateral hip rotation range of motion asymmetry in patients with sacroiliac joint regional pain. Spine. 1998. 23(9): 1009-1015.
Clavel Jr AL. Sacroiliac joint dysfunction: from a simple pain in the butt to integrated care for complex low back pain. Techniques in regional anesthesia and pain management. 2011; 15: 40-50.
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 evidencebased approach. Upper Saddle River, New Jersey. Pearson Prentic Hall; 2008.
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References cont.
References cont.
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.
Farrell KC, Reisinger KD, Tillman MD. Force and repetition in cycling: possible implications for iliotibial band friction syndrome. Knee. 2003. 10 (1): 103-109.
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.
Holmes JC, Pruitt A, Whalen NJ. Lower extremity overuse in bicycling. Clinics in Sports Medicine. 1994; 13:187-203.
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.
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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.
Levangie PK. The associated between static pelvic asymmetry and low back pain. Spine. 1999; 24 (126) : 1234.
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Millslagle D, Rubbelke S, Mullin T, Keener J, Swetkovich. Effects of foot-pedal positions by inexperienced cyclists at the highest aerobic level. Perceptual and Motor Skills. 2004; 98: 1074-1080.
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.
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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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References cont.
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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.
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.
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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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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. 82
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