Functions of footwear
Protect the foot, provide traction, motion control and shock absorption during activities.
Disadvantages of footwear
Decreased sensory perception and increased risk of injury due to increased friction on playing surfaces
Upper components of footwear
Vamp, toebox, quarter, heel counter, throat, insole board
Vamp
The part that covers the forefoot and the toes
Toe box
The part that surrounds the toes. Should be deep, wide and long enough to allow the toes to fully extend and to allow good alignment of the first toe during push-off. Extra-depth toe box for claw or hammer toes. Mudguard (toe-cap)-a piece of leather or ru
Quarter
The back half of the upper
Heel counter
The rigid material surrounding the heel to stabilize the rearfoot, can be reinforced by a rearfoot stabilizer or a heel counter medial extension for overpronators.
Foxing
An additional piece of leather or rubber covering the counter externally in athletic shoes
Throat
The connection between the vamp and the quarter, it dictates the maximal forefoot girth.
Bal method
The front edge of both quarter panels are stitched together and covered with the back edge of the vamp
Blucher method
The front edge of both quarter panels are not stitched together and placed on top of the vamp. This allows a larger forefoot girth by broadening the throat
Parallel lacing for ____________ _____________
Dorsal bump
Loop lacing for __________________ ____________
Slipping heel
Insole board
The portion of the shoe contacting the foot
Sock liner (insert)
A piece of material placed on top of the insole board (glued in place or removable), it is made of a foam base covered with a nylon or cloth material. It reduces shear stresses assist in shock absorption and absorb perspiration
Lower components of footwear
Midsole, outsole, shank, heel
Midsole
The component between the shoe upper and the outsole, primary functions are shock attenuation (cushioning) and stability (durability). It also increases contact surface to distribute plantar pressure. Can use a variety of materials (EVA, PU, encapsulated
EVA (ethylene vinyl acetate)
Good cushioning but less durability
PU (polyurethane)
Good durability, heavier but less cushioning
Encapsulated EVA or PU
PU-encapsulated EVA has the durability of PU and the cushioning of EVA
___________ is the weakest part of the shoe
Midsole (because the cushioning foam (EVA or PU) wears out and loses its ability to cushion within a few hundred miles)
Shock absorption capacity ______________ as mileage _____________
Deteriorates, increases
When does the shoe suffer a loss of cushion?
300-400 miles (by 500 miles there is a 40% loss)
What is the solution to reduce cushion deterioration?
Reduce the amount of foam material in the midsole to improve durability and longevity. Ex. Nike air (air/nitrogen chambers encapsulated in PU or EVA), asics gel (silicon gel cushioning pad in EVA), new balance absorb (rubber compound blended with a copoly
Multidensity midsoles provide _________ medial support (__________ density) and __________ cushioning (___________ density) on lateral side
Firm, higher, softer, lower
Outsole
The portion of the shoe that is in contact with the ground, Functions include durability, cushion, flexibility and traction. A rocker sole can be used to alleviate pressure on metatarsal heads and facilitate walking (shortens GRF moment arm to ankle joint
Tread patterns
Provide traction and aid in shock absorption
Waffle or nubbed
Increased traction on dirt and grass, good for road and off-road running
Horizontal bars or herringbone
Better suited to asphalt or concrete surfaces, only good for road running
Shank
The bridge between forefoot and rearfoot to provide stability of the midfoot
Heel
Approximately 1/2 to 1 inch higher than the forefoot to decrease stress on Achilles tendon
Last
The mold or model that determines the fit of the shoe, including, height of the instep, the height of the toe box, the width of the forefoot, the width of the heel. It also determines the curvature of the forefoot in relation to the rearfoot. Three types
Straight last
Symmetrical about the long axis of the sole, it provides support and stability for mobile feet and overpronators
Curved last
It allows more flexibility and mobility for rigid, high arched feet
Semicurved last
Provides intermediate stability
Combination last
Wider across forefoot, narrower at the heel, extra-depth toe box last, bunion least, etc.
Fitting length
Both feet should be measured and shoes should be fitted to the largest. Allow 1/2 inch length for the longest toe (not necessarily the big toe)
Heel to ball of foot length
The shoe should be designed to bend at the level of the MTP joints, proper toe break distance of the foot can be measured prior to fitting. After the shoe is selected, bend the shoe to determine the toe break, these two measures should match
Forefoot width
Measure the ball of foot width at the widest point, pinch test, always fit forefoot first. If heel counter is too wide, it can be filled in by padding
Snug heel fit
The heel of the shoe should fit snugly to provide rearfoot stability. Rearfoot stabilizer, external foxing and heel counter medial extension help to increase rearfoot stability, especially important for overpronators.
Heel fit is critical for women due to _____________ heel
Narrower
Last selection
Trace the person's foot in seated position (knees and hips flexed at 90 degrees, subtalar joint in neutral) on a piece of paper, use the cut-out to fit over the sock liner or lay inside the new shoe
Arch support
The insole molded sock liner arch support should be properly positioned to provide support and cushioning
When should you shop for shoes
The middle of the day when the feet are at their largest, wear the same socks
Types of athletic shoes
Motion control, stability, cushion, performance training, minimalist
Motion control shoes
Most rigid, limit overpronation or slow the rate of overpronation, usually heavy and durable.
Feature: rearfoot stabilizer and arch support, PU midsole (durability), carbon rubber outsole (durability), straight last (maximal medial support).
What are motion control shoes indicated for?
Overpronators needing control, flat feet, orthotics wearer desiring firm midsole and outsole, heavy runners desiring durability
Stability shoes
Blend of cushioning, medial support and durability.
Features: dual density midsole (cushion and durability), semicurved last
What are stability shoes indicated for?
No sever motion control problems, desiring medial support and durability, normal arches
Cushion shoes
Least medial support, maximal cushioning
Features: EVA, air, gel midsole, blown rubber outside, curved last
What are cushion shoes indicated for?
Rigid, immobile feet, high arches, efficient runners desiring a highly-cushioned flexible ride
Performance training shoes
Racing shoes or training shoes for biomechanically efficient runners
Features: light weight (<10 oz), snug fit, various degrees of support and cushioning
What are performance training shoes indicated for?
Racing, normal or high arches, biomechanically efficient runners
Minimalist shoes
Mimic barefoot running with midfoot or forefoot strikes
Features: very light weight, low profile with midsole/outsole thickness ranging from 4mm to 20mm, very flexible
Geriatric shoes
Hammer or claw toes, bunion, edema, metatarsalgia, diabetic foot
Shoes for hammer or claw toes
Extra depth toe box
Shoes for bunion
Wider forefoot girth by bunion last, combination last, blucher style oxford allowing extra girth at the throat
Shoes for edema
Extra-depth shoes
Shoes for metatarsalgia
Full-length cushioned insole and rocker sole to relieve pressure on metatarsal heads
Shoes for diabetic foot
Extra-depth, soft leather upper to avoid pressure on the skin, well-cushioned total contact insole to evenly distribute plantar pressure and reduce shock, good traction outsole to prevent falling, crepe or rubber outsole to provide shock absorption, rocke
Foot orthotic
A device used inside the shoe to support and align the foot
Functions of foot orthotic
Support or "balance" the foot in order to eliminated the need for the foot to compensate for the structural deformity or malalignment, control foot motion by controlling the magnitude and rate of pronation, provide shock absorption, redistribute plantar p
What does a comprehensive intervention include?
Proper footwear, extrinisic and intrinsic soft tissue management (strengthening, stretching joint and soft tissue mobilization, gait and balance training)
Classifying orthotics based on material
Flexible/soft, semi-rigid, rigid
Flexible/soft orthotic
Minimum control, maximum flexibility and shock absorption
Semi-rigid orthotic
Reduced control, moderate shock absorption
Rigid orthotic
Maximum control, minimum shock absorption
Classifications of orthotic by intended goal
Biomechanical (functional), accommodative, pediatric
Biomechanical/functional orthotic
Control excessive/extreme motion
Accommodative orthotic
Shock absorption and support foot
Pediatric orthotic
Control hypermobile flat foot
Classification of orthotic by fabrication method
Pre-fabricated, custom-made, semi-custom: heat moldable
Components of an orthotic
Shell, top cover, bottom cover, forefoot extension, posts, soft tissue supplements or modifications
Shell
Body of the foot orthotics. Ideally constructed from cast impression of patient's foot, conforms exactly to plantar contour and has cupped heels, it should provide total contact to redistribute plantar pressure, ends just proximal to metatarsal heads, det
Top cover
Material on top of the shell. Variable length: to mets, to sulcus or to toes
Bottom cover
Material covering the bottom of the shell
Forefoot extension
Distal to shell. Length: to sulcus or to toes, 1/18 or 1/16 inch
Posts
Angled, wedge shaped material applied to selected locations on the plantar aspect of the shell. Designed to support or "balance" a malaligned foot in the frontal plane. Theoretically, the post allows the foot to function about a neutral position and preve
Varus post
Thickest part of the wedge is placed on the medial side of the foot, often used for patient with excessive pronation
Valgus post
Thickest part of the wedge is placed on the lateral side of the foot. It is often used for patient with excessive supination
Forefoot varus post
Designed to bring the ground up to the medial forefoot
Forefoot valgus post
Designed to bring the ground up to the lateral forefoot
Rearfoot varus post
Designed to control calcaneal eversion (STJ pronation) and associated excessive tibial internal rotation during loading response (heel strike to foot flat)
Rearfoot valgus post
Designed to control calcaneal inversion (STJ supination) and associated excessive tibial external ovation during loading response, it is rarely prescribed
Rearfoot varus deformity
Can be thought of as the calcaneus with the medial corner shaved off. When compensated, the calcaneus everts to meet the ground (foot pronation), a medial wedge can help prevent this compensatory pronation
What does the amount of posting depend on?
Degree of deformity (post from 60-100% of measured deformity), patient's response to posting, constraints of the shoe
In general, the maximum amount of forefoot and rearfoot postings that fit comfortably in the shoe is ____ degrees and ______ degrees respectively
8, 5-6
Soft tissue supplements or modifications
Deep heel cup, heel lift, heel spur relief, medial flange, arch reinforcement (arch filler) or navicular pad, metatarsal pad/bar, first ray cut out
Considerations for selection of foot orthotic
Movement dysfunction and diagnosis, physiological age of the patient, body weight, activity for which the device will be used, degree of control of STJ and MTJ provided, shock absorption provided, general health status of the patient
Reliability of subtalar joint palpation measurement
Poor to moderate inter and intrarater
Reliability of FF/RF varus/valgus
Poor interrater reliability of the small goniometric measurement required to determine the forefoot and rearfoot alignment
Root theory for casting in subtalar joint neutral
Suggested that subtalar joint functions around "subtalar neutral position" during gait cycle. Based on a study of two male subjects.
Subtalar neutral position
Determined when the patient is in prone, intrinsic foot deformities (forefoot/rearfoot varus/valgus) can be measured and orthotic posting can be prescribed accordingly
Current understanding of subtalar neutral
Resting calcaneal stance position" rather than subtalar neutral position is the functional neutral position of the foot during gait.
Resting calcaneal stance position
The angle between the calcaneal bisection and the midline of lower 1/3 calf measured in bilateral weight bearing position
Effectiveness of foot orthotics
Orthotics have shown changes in rearfoot motion parameters (decreased maximum pronation, maximum pronation velocity, time to maximum pronation and total rearfoot motion (studies that reported similar findings for one variable did not always report compara
Problems with applying research findings to clinical applicaion
Footwear and foot orthotics wear not standardized, shoe counter substantially modified to permit analysis of actual rearfoot motion within the shoe
What should you use to determing the functional posting amount (in mm)
Treatment direction test and taping