More than you ever wanted to know about the foot l.jpg
Sponsored Links
This presentation is the property of its rightful owner.
1 / 69

More than you ever wanted to know about the foot PowerPoint PPT Presentation


  • 437 Views
  • Uploaded on
  • Presentation posted in: General

More than you ever wanted to know about the foot. MAJ Joel L. Shaw Sports Medicine 24 May 2007. Overview. Describe foot and ankle joints Joint actions during running Related pathology How to prescribe running shoes. Foot function. 1. Accept vertical forces during heel strike

Download Presentation

More than you ever wanted to know about the foot

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


More than you ever wanted to know about the foot

MAJ Joel L. Shaw

Sports Medicine

24 May 2007


Overview

  • Describe foot and ankle joints

  • Joint actions during running

  • Related pathology

  • How to prescribe running shoes


Foot function

  • 1. Accept vertical forces during heel strike

  • 2. Absorb and dissipate these forces across a flexible mid- and forefoot during pronation

  • 3. Provide propulsion as the foot becomes a rigid lever with resupination and toe-off


Articulations

  • Subtalar

  • Talocalcaneonavicular

  • Calcanealcuboid

  • Midtarsal

  • Tarsometatarsal

  • Metatarsophalangeal

  • Interphalangeal


Subtalar

  • Triplanar

    • Supination vs. Pronation

  • Bones: inferior talus, superior calcaneus

  • Alternating concave-convex facets limit mobility

  • Ligaments- talocalcaneal, interosseous talocalcaneal, cervical


Subtalar joint

  • Supination

    • Inversion by calcaneus

    • Abduction by talus.

    • Dorsiflexion by talus

  • Talar abduction causes external rotation of the tibia

  • Position of most stability


Subtalar joint

  • Pronation

    • Eversion by calcaneus

    • Adduction by talus

    • Plantarflexion by talus

  • Talar adduction causes internal rotation of the tibia

    • May increase Q angle

  • Increased flexibility and shock absorption


Subtalar joint

  • Clinical significance

    • Mobility

    • Shock absorption

    • Stability


Midtarsal joint

  • Functional joint- includes talonavicular and calcaneocuboid joint

  • Triplanar supination/pronation- primarily DF/PF and abd/add

  • Navicular- highest point of medial arch


Midtarsal joint

  • Assist pronation/supination of the subtalar joint

  • Maintain normal weight bearing forces on the forefoot

  • Control/communication between rear foot and forefoot


Metatarsophalangeal joint

  • Biplanar- mostly dorsiflexion/plantarflexion with 10 degrees of abduction/adduction

  • Dorsiflexion- allows body to pass over foot while toes balance body weight during gait

  • Plantarflexion- allows toes to press into ground for balance during gait


First ray

  • Functional joint

  • Bones- Navicular, 1st Cuneiform, 1st Metatarsal

  • Plantarflexion at late stance to assist 1st MTP dorsiflexion

  • Peroneus longus and abductor hallicus brevis muscles


Plantar fascia

  • Causes tension along the arch

  • Supination facilitated as arch heightened

  • Windlass effect


Windlass effect

  • Webster’s: machine for pulling a rope around a drum. Pulley system to lift anchor in a boat.


Windlass effect

  • Tension in the aponeurosis secondary to toe extension elevates the arch by acting as a pulley around which the aponeurosis is tightened.


Ligaments

  • Spring ligament

    • Tension wire which helps maintain arch

    • Helps rigidity during propulsion

  • Long plantar ligament

  • Plantar aponeurosis

  • Short plantar ligament


Function of arches

  • Stability

    • Distribution of weight

  • Mobility

    • Dampens shock of weight bearing

    • Adaptation to changes in support surfaces

    • Dampening of superimposed rotations


Stance phase

40% of gait cycle

2 phases

Absorption

Propulsion

Swing phase

60% of gait cycle

2 phases

Initial swing (ISW)- 75%

Terminal swing (TSW)- 25%

Running gait


Double float

Stride length

Step length

Cadence

Velocity=stride length x cadence

Running gait


Running gait

  • Kinematics vs. Kinetics

    • Kinematics- motion of joints independent of forces that cause the motion to occur

    • Kinetics- study of forces that cause movement, both internally and externally

      • Internal- muscle forces

      • External- ground reactive forces


Ankle/foot kinematics

  • Ankle joint

    • Dorsiflexion/plantarflexion

  • Foot joints

    • Triplanar

    • Pronation and supination


Running gait- ankle kinematics

  • Absorption and midstance

    • Rapid dorsiflexion (response to increased hip and knee flexion)

    • Decreased plantarflexion in running decreased supinationcause of increased running injuries??


Running gait- foot kinematics

  • Subtalar motion determined by muscular activity and ground reactive forces

  • Midtarsal motion determined by subtalar position


Calcaneus/talus supination

Increase midtarsal obliquity

Lock joint

“Rigid lever”

During propulsion and ISW

Calcaneus/talus pronation

Parallel midtarsal joints

Increased ROM

“Mobile adapter”

Mid stance

Running gait- midtarsal joint


Axis of transverse tarsal joint

O'Connor FG, Wilder RP: Textbook of Running Medicine, McGraw Hill Companies, 2001. Page 13.


Running gait- foot kinematics

  • Absorption

    • Pelvis, femur, tibia internally rotate

    • Eversion and unlocking of subtalar joint

    • Pronation of midtarsal joints

      • Allows mobility and shock absorption.

      • Able to adapt to ground surface.

    • Plantar fascia- relax medial arch


Running gait- foot kinematics

  • Propulsion

    • Pelvis, femur, tibia externally rotate

    • Inversion/locking of subtalar joint

    • Supination of forefoot

    • Plantar fascia- increase medial arch stability and invert heel

    • Metatarsal break- promote hindfoot inversion and external rotation of leg


Running gait- foot kinetics

  • External forces- ground reactive forces

    • Vertical- 3-4 times body weight

    • Fore-aft- 30% of body weight

    • Medial-lateral- 10% of body weight

    • Newton’s third law

  • Internal forces- muscle forces


External forces

  • Foot strike pattern

    • Forefoot Midfoot Rearfoot


Rearfoot striker

  • 80% of runners

  • Initial contact- posterolateral foot

  • Center of Pressure (COP)

    • Outer border of rear footprogresses along lateral borderthen across forefoot medially toward 1st and 2nd metatarsal head


Midfoot strikers

  • Most other runners

  • Initial contact- midlateral border of foot

  • COP

    • Lateral midfootprogresses posteriorly (corresponds to heel contact)rapidly moves to the medial forefoot


Evaluation of running injuries

  • Training log

  • Shoe examination

  • Arch appraisal

  • Gait analysis

  • Running shoe prescription


Training log

  • Weekly mileage

  • Transition point

  • Increase in distance or intensity

  • Increase in mileage >10% per week

  • Change in terrain or running surface


Shoe examination

  • Current running shoes

    • Age (days and miles)

    • Replacement frequency

    • New brand or model? (change biomechanics)


Shoe examination

  • Outsole wear

    • Lateral heel vs. inside heel vs. lateral sole

  • Midsole wear

    • Heel counter tilt

    • Midsole wrinkling, tilt, or decomposition


Shoe wear

  • Based on foot strike pattern, initial contact, and center of pressure

  • Neutral gait

    • Wear on lateral aspect of heel

    • Uniform wear under the toes


Shoe wear

  • Overpronator

    • Excessive wear on medial portion of heel and forefoot

  • Underpronator

    • Excessive wear on lateral heel

    • Wear on entire lateral portion of the outersole


Arch appraisal

  • Standing arch contour

  • “Wet test”

  • Static evaluation=running evaluation?


Biomechanical function

  • Required functions of locomotion

    • Adaptation

    • Shock absorption

    • Torque conversion

    • Stability

    • Rigidity


Biomechanical assessment

  • Video gait analysis

  • Always base on running gait, not arch height

  • Evaluate shoe wear


Gait analysis

  • Behind- location of heel strike, foot motion during single stance, foot engaged at push-off

  • Side- gastroc-soleus flexibility, great toe dorsiflexion

  • Treadmill-based analysis

  • Force plate analysis


Neutral gait

  • Level Heel Throughout Gait Cycle

  • 90 Degree Medial Angle Throughout Gait Cycle


Intrinsic abnormalities

  • Pes cavus- abnormal supination

  • Pes Planus- abnormal pronation


Normal

Late stance phase

Provides rigidity, support, propulsion

Facilitates lower leg external rotation

Abnormal

Minimal pronation at subtalar joint

Little drop of medial longitudinal arch

Supination


Abnormal supination- signs

  • Lateral Leaning Foot Surface Placement

  • Inflexible Foot

  • Callus- 1st and 5th metatarsal heads

  • Clawing of 4th and 5th digits


Stable and rigid foot

Lacks flexibility and adaptability

Poor gastroc-soleus flexibility

Achilles tendonitis

Plantar fasciitis

Poor shock absorption

Tibial and femoral stress fractures

Abnormal supinators


Normal

Early in stance phase

Provides flexibility, adaptability and shock absorption

Facilitates lower leg internal rotation

Abnormal

Continues throughout stance phase

Pronation


Mild Overpronation- signs

  • Slightly Greater than 90 Degree Angle Throughout Gait Cycle

  • Medial Leaning Foot Surface Placement

  • Some Ankle Instability/ unstable position


Severe overpronation- signs

  • Significant Medial Leaning of Surface Foot

  • Great Instability

  • Excessive internal tibial rotation

  • Increased medial stress


Overpronators

  • Patellofemoral pain

  • Popliteal tendonitis

  • Posterior tibial tendonitis

  • Achilles tendonitis

  • Plantar fasciitis

  • Metatarsal stress fracture


Arch Height Will Produce Different Levels of Flexibility

  • Normal feet:

    • are flexible as they grip the ground and become stiff at push off

  • Flat feet:

    • are flexible as they grip the ground and remain flexible at push off

  • High arched feet

    • are inflexible and do not adjust to terrain well, but provide a good base for push off.


Running Shoe Design

  • In an attempt to minimize injuries, running shoes need to provide:

    • Cushioning

    • Motion Control

    • Support


Anatomyof the Running Shoe

Uppers

Midsole

Outersole

Midsole


Anatomy of the Running Shoe

Heel notch

Lacing system

Toebox

Heel counter

Tongue


Anatomy of the Running Shoe

Flex Grooves

Split Heel


Anatomy of the Running Shoe Last (Curvature)Straight, Semi-curved and Curved


Anatomy of the Running Shoe

  • Lasts (Shoe Template)

    • Board

    • Slip

    • Combination

  • If you cannot remove insole, remove shoe…it is of poor quality


Stabilizing Features

Support is added to the inside or medial portion of the heel to counteract the foot rolling inward (pronation)


Running Shoe Selection

  • The three basic types of running gait based on ankle biomechanics are: over-pronation, neutral and underpronation

  • Shoes should be bought to accommodate your running gait, not your arch height!


Shoe prescription

  • High arch- curve-lasted, cushion shoe

  • Flat arch- motion control or stability shoes with firm midsoles and straight to semi-curved lasts

  • Neutral arch- cushion or stability shoe


Orthotics

  • Effectiveness

    • Gross, et al. 90% with symptom improvement

    • Schere. 81% with complete symptoms relief

    • Blake and Denton. Reduced pain associated with plantar fasciitis by 80%.


Orthotics

  • Motion control

    • Control excessive pronation

  • Shock absorption

  • Pressure relief in specific area

    • Plantar heel or great toe metatarsophalangeal

  • Redistribution of forces away from area

    • Metatarsal pad for metatarsalgia/Morton’s neuroma


Orthotics

  • Adjunct to rehab and training modification

  • Return athlete to full function

  • Prevent further injury

  • Functional orthoses

    • Alter foot function

    • Guide foot through stance phase

    • Promote biomechanical efficiency


Orthotics

  • Start with soft temporary orthotic

  • Over-the counter prefabricated devices

    • Most athletes report improvement

  • Incomplete improvementcustom orthotic


High arch orthotic

  • Dropped forefoot

  • Plantarflexed first metatarsal and forefoot valgus

  • Decreased subtalar range of motion

  • Plantarflexed first ray, unstable cuboid

  • Peroneal cuboid syndrome


Pronated foot orthotic

  • Flat medial arch

  • Unstable rearfoot and excessive motion of plantar calcaneal fat pad

  • Weak plantarflexion of first metatarsal head and weak “windlass” effect


Common mistakes

  • Only looking at standing gait

  • Failure to evaluate various needs of different runners

  • Need of different orthoses for running and everyday activity


Summary

  • Understand normal foot biomechanics- pronation vs. supination

  • Evaluate with functional arch and shoe wear

  • Signs of abnormal arch

  • Match shoes and orthotics to running alignment- correct shoes and over-the-counter inserts first


Questions??


  • Login