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Shoddy-The Impact of Shoes & The Benefits of Going Barefoot

Going barefoot is healthy, safe, and fun! Kick off your shoes and explore.

Daniel Howell

on 23 August 2018

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Transcript of Shoddy-The Impact of Shoes & The Benefits of Going Barefoot

The Anatomy of Your Feet, the Biomechanics of Ambulation, and the Impact of Footwear
Using Your Feet
Bones of Foot & Ankle
25% of the bones in the body (52/206) are found in the foot

The seven tarsal bones are the bones of the hindfoot and midfoot:
1st-2nd-3rd cuneiform

Bones of the forefoot:
5 metatarsals
14 phalanges
Natural "Arch Supports"
The talus accepts body weight from the tibia and transfers the weight to hindfoot (50%) and forefoot (50%)

The weight is transferred to forefoot by the head of talus using the "spring ligament"

Spring ligament spans from sustentaculum tali (calcaneus) to navicular tuberosity

The talus is the only foot/ankle bone with no tendon or ligament attachment

Spring ligament & plantar fascia are main passive support for foot arches
Standing At Ease
Little muscle activity is required to stand at ease

When standing, hips and knees are fully extended and in most stable positions

The body's center of gravity is slightly anterior to the rotational pivot point of the ankle (subtalar joint)

Thus, the body tends to sway forward and this tendency is countered by posterior leg muscles (gastrocnemius and soleus)

Lateral sway is countered by hip abductors (gluteal muscles and tensor fasciae latae) and muscles of lateral leg compartment (fibularis longus and brevis)
The Foot Arches
There are three arches in each foot: medial longitudinal, lateral longitudinal, transverse

Arches are distinctly human

Like architectural arches, each foot arch has a "keystone" bone

The arches are supported by muscles and ligaments, as well as bone configuration

Functions of the arches:
static weight distribution
dynamic weight redistribution
shock absorbers
mediate the Windlass Mechanism
The Foot Arches
When walking, the foot arches absorb ~15% of the force of impact upon landing; this energy is released by a spring action of the arch upon lift off

The arches distribute body weight from heel-to-toe in a complex pattern during the stance phase of walking

Standing, the arches distribute body weight between hindfoot and forefoot.
Natural "Arch Supports"
Passive Support (ligaments):
plantar aponeurosis
calcaneonavicular (spring) ligament
long plantar ligament
short plantar ligament

Active support (muscles):
intrinsic plantar muscles
tibialis posterior
flexor hallucis longus
tibialis anterior
fibularis longus
Walking: Barefoot v Shoes
Ambulation is one of the most complex biomechanical achievments of the body
At least 1/2 your muscles and bones are used to complete a single step
Walking: Barefoot v Shoes
Footwear on Posture & Gait
Footwear is ubiquitous in Western society
Shoes must be considered when studying biomechanics of walking and foot health
Shoes can dramatically alter stance, posture, and ambulation (walking and running)
Shoes can affect the feet, ankles, knees, hips, and spine
Shoes can affect the skin of the feet
Footwear on Posture & Gait
Elevated heels shift body weight anteriorly; the higher the heel, the more the shift

90% of the body's weight is supported by the metatarsal heads in 3-inch heels

The toes are kept hyperextended and the windlass mechanism is disengaged

Elevated heels engage muscles to keep the body from falling forward (triceps surae, gluteus maximus); Pelvis is tilted ~15 degrees, curves in spine are exaggerated

Body weight is also shifted forward in the knee; knee osteoarthritis is 4x higher in women than in men
The Windlass Mechanism
A windlass is a leverage system used to lift heavy weights

Consists of a crank, shaft, and rope (connected to weight)

In the foot, a windlass is created by the plantar aponeurosis winding around MTP joints as heel is elevated
The Windlass Mechanism
When the triceps surae lifts the heel off the ground, the toes hyperextend and the plantar aponeurosis winds up and tightens

Pulls foot bones together to "lock" numerous intertarsal joints; foot stiffens

Windlass helps convert the foot from a supple landing platform to a rigid propulsion rod

Foot shortens ~1 cm
Footwear on Posture & Gait
The narrow toe box of footwear reduces the efficacy of the great toe during push off

Narrow toe box eventually pushes hallux laterally (hallux valgus) and short toe box causes hammer toe, ingrown toenails

The force during push off is shifted laterally to the 2nd and 3rd toes
Source: The Textbook of Hallux Valgus and Forefoot Surgery (2000). ed. V. J. Hetherington.
Kerrigan et al. "Knee osteoarthritis and high-heeled shoes," (1998) The Lancet 352:1399-1401
Shakoor & Block "Walking barefoot decreases loading on the lower extremity joints in knee osteoarthritis," (2006) Arthritis & Rheumatism 54(9):2923-2927
Kerrigan et al. "Moderate-heeled shoes and knee joint torgues relevant to the development and progression of knee osteoarthritis," (2005) Archives of Physical Medical Rehabilitation 86 (5):871-875
The shift is present while wearing shoes and persists when shoes are removed
Footwear Encourages Overpronation
Shoes destabilize the foot and encourage overpronation

Destabilizing factors include:
narrow toe box
elevated heel
toe spring

Corrective attempts using orthotics (arch support) and stiff instep support

Toe springs are required because of the stiff nature of the shoe sole
Footwear on Posture & Gait
People wear shoes when they are not necessary
People wear shoes that are fashionable, not functional
"There is no such thing as a sensible shoe."
- Dr. William Rossi

"Footwear is the greatest enemy of the human foot."
- Dr. Samuel Shulman
Footwear on Walking
Footwear on Running
Modern running shoes possess:
thick, hard soles
soft, padded insoles
toe springs
elevated heels
arch supports
panel supports

Running shoes dramatically reduce tactile feedback from foot sole
Shoes promote over-striding, over-extended knee, dorsiflexion, and heel striking

Barefoot promotes flexed hip, knee, and ankle; flatfoot landing
Footwear on Running
Running in shoes creates a sharp, transient ground reaction force (GRF) that is absent when barefoot

The impact forces on the joints are much higher in shoes (heel striking, knee extended)

Running barefoot, impact forces on knee and hip are zero (forefoot striking, knee flexed); forces absorbed by soft tissues in foot and leg

Try jumping off a table and landing heel first!
Athlete's Foot & Toenail Fungus
Foot sole has a high density of sweat glands, but closed-toe shoes do not allow sweat to evaporate

The dark, warm, moist environment of the shoe creates a breeding ground for microorganisms, the cause of foot odor
Why Do We Wear Shoes?
The Foot
Podiatry is the specialized field that deals with the study and care of the feet

The ankle refers the narrowest part of the distal leg and malleoli

The foot provides a platform of support for the body when standing and a landing / propulsion platform in locomotion

The foot consists of 7 tarsals, 5 metatarsals, and 14 phalanges

Divided into three zones:
hindfoot - talus & calcaneus
midfoot - navicular, cuboid, cuneiforms
forefoot - metatarsals & phalanges
The Foot
The part of the foot contacting the ground is the sole, or plantar region

The most superior part is the dorsum of the foot

The sole of the foot underlying the calcaneus is the heel

The sole underlying the metatarsal heads is the ball of the foot

The 1st digit is the hallux (great toe) and the little toe is the 5th digit

The skin of the foot is unique in its thickness (five epidermal layers), skin prints, sweat gland density, and innervation
Foot Muscles
There are 20 muscles in the foot

Two on the dorsum of the foot
extensor hallucis brevis
extensor digitorum brevis

The other 18 muscles are arranged in four layers

The muscles of the foot
stabilize the arches while standing and moving
help maintain balance
absorb impact when landing
Vascular Supply of the Foot
The sole of the foot is supplied by the
posterior tibial artery
The dorsum of the foot is supplied by the
anterior tibial artery
Pulse points: dorsalis pedis artery and posterior tibial artery
Note the position of abductor hallucis over post. tibial a.
Foot Maladies
The majority of foot problems in Western culture is from the overuse of shoes
athlete's foot
toenail fungus
Pseudomonas infections
hallux valgus
ingrown toenails
hammer toes
fallen arches
plantar fasciitis (fasciosis)

knee osteoarthritis
hip / back pain
Hallux Valgus & Bunions
Hallux valgus = An abnormal deviation of the great toe (hallux) laterally toward the other toes

Often used synonymously with "bunion" but is not the same

Bunion = an abnormal enlargement (bony or bursal) of the 1st MTP joint

Bunions and Hallux valgus are most common in shoe-wearing societies, though there seems to be a genetic predisposition to these conditions

Irreversible damage caused by footwear
Hammer Toe & Ingrown Toenails
Hammer toe results when the extensor tendons are too long and/or flexors are too short and pull too tightly

Known to be caused by shoes with short, narrow toe boxes and/or shoes with toe springs
Is not known to be caused by flip-flops (as is commonly purported)

Likewise, ingrown toenails often results from excess pressure on the toes by shoes
Plantar Fasciitis or Plantar Fasciosis?
Plantar fasciitis (PF) is the most common foot complaint in the United States

Characterized by sharp heel pain, especially in the morning

Treatments include steroid injections, physical therapy, and orthotics
These treatments rarely work
Flatfoot & Fallen Arches
Flatfoot has been called a "silent epidemic" that affects 25% of the population

Modern footwear immobilizes the foot, especially the arch --> muscle atrophy, weak ligaments, fallen arches

Caused primarily by shoes with arch supports, toe springs, and elevated heels

Walking barefoot can strengthen and lift low arches
Protection... from injury
Protection... from injury
Puncture wounds in shoes can be significantly more dangerous than puncture wounds barefoot

A 1997 study of 44 children admitted to hospital for nail punctures (22 barefoot, 22 shod):
50% of shod children suffered pseudomonas infection
0% of barefoot children suffered pseudomonas infection

Frequently, shoe particulate matter is embedded in the wound
Podiatry is the only field of medicine in which a healthy body part is considered insufficent to perform its function without human intervention ("support")

Support structures are generally recognized to weaken body parts

Casts are used to immobilize injured body parts to facilitate healing, but must be removed asap to prevent causing additional injuries
Why Do We Wear Shoes?
"There's no such thing as a sensible shoe."
Dr. William Rossi (2001)

"Footgear is the greatest enemy of the human foot."
Dr. Samuel Shulman (1949)

"The footwear of civilization is rarely modeled to conform to the contour of a normal foot. The dictum of fashion has greater influence than reason."
Dr. Phil Hoffman (1905)
Protection... from germs
Many people believe shoes protect us from germs, but shoes are incubators for growing bacteria and fungi

The leading cause of athlete's foot and toenail fungus is shoes and socks, not going barefoot

Hookworm was a real threat in the United States prior to indoor plumbing, but has since been eradicated.
Shoes do offer some protection from acute injuries.

But, acute risks are actually low, especially for experienced barefoot walkers / runners

>20,000 women/year hospilized because of high heels

Risk v Benefit ?
The shoe is a cast for the foot.

Shoes immobilize the foot
reduce blood & lymph flow
cause atrophy of muscles
weaken ligaments, tendons, soft tissues
alter the biomechanics of standing, walking, and running
"Athlete's foot does not occur among people who traditionally go barefoot. It's moisture, sweating, and lack of proper ventilation of the feet that present the perfect setting for the fungus of athlete's foot to grow."

~ The American Academy of Dermatology*
Athlete’s Foot
Most prevalent skin infection
15% in general population (7:1 male:female)
24% in male marathon runners; 6% female

Toenail fungus
2:1 male:female
rare before 1900’s
*"Getting a Jump on Athlete's Foot" by Amy Paller, 2002. Dermatology Insights 3(1):30
Shoes Deform Your Feet
This is not new information

Photo compares the feet of a Westerner with the feet of a Philipino native who has never worn shoes in 30+ years

Photo taken by Dr. Phil Hoffman in 1905
Damaging Features in Shoes
Elevated heel
Thick, hard outer sole
Thick inner sole
Toe spring
Tapered toe box
Arch support
Curved last
Large sole surface area
Instep support panels
Sinching features (laces)
Damaging Features in Shoes
Elevated heel
Thick, hard outer sole
Thick inner sole
Toe spring
Tapered toe box
Arch support
Curved last
Large sole surface area
Instep support panels
Sinching features (laces)
Damaging Features in Shoes
Elevated heel
Thick, hard outer sole
Thick inner sole
Toe spring
Tapered toe box
Arch support
Curved last
Large sole surface area
Instep support panels
Sinching features (laces)
These Are Your Feet
Foot & Ankle Movements
ankle flexion
ankle extension
ankle eversion
ankle inversion
The Unique Skin of the Feet
print ridges
tight attachment
extra thick epidermis (+stratum lucidum)
The skin of hands and feet are unique in several ways:
Thermal Regulation
print ridges
tight attachment
extra thick epidermis
abundant sweat glands
The skin of hands and feet are unique in several ways:
High Innervation
print ridges
tight attachment
extra thick epidermis
abundant sweat glands
highly innervated
The skin of hands and feet are unique in several ways:
Unique "Feetures" of Your Feet
The Impact of Footwear
Flatfoot & Fallen Arches
Flatfoot has been called a "silent epidemic" that affects 25% of the population

Cause: arch supports are the primary cause of flat feet.
Treatment: Walk barefoot as much as possible
Prevention: Avoid footwear with arch support, toe springs, elevated heels
WHY ??
Footwear on Running
Shoes not only change biomechanics of lower limb actions, but the entire kinetic chain

Posture is altered by running in shoes and may contribute to early fatigue in many runners (and "stiches")
The elevated heel and toe spring convert the complicated stepping motions into a rolling motion

The foot is immobilized inside the shoe; little activity by intrinsic foot muscles lead to atrophy

windlass mechanism, shock absorption, and spring action of arches dramatically reduced by immobilization and arch support
Flatfoot has been called a "silent epidemic" that affects 25% of the population

Google "How to treat flat feet?"
Causes: genetics, injuries
Treatment: arch supports, surgery
Prevention: "Most cases are not preventable."
Footwear on Running
Running shoes almost always have a flared shoe sole (i.e., wider than sole of foot)

This is designed to stabilize the foot, but destabilizes the foot when landing on roots, rocks, etc.

The stiff side panel support transfers the twist to the ankle, and the leverage of the flared sole amplifies the torque
Which Shoe Is You?
print ridges
tight attachment
extra thick epidermis
abundant sweat glands
highly innervated
Epiphany = an "Ah ha" moment
toe flexion
toe extension
toe hyperextension
toe abduction
toe adduction
arch compression
How Do You Know What You Know?
Where Do We Get Our Facts?
There are only two sources for facts:
1. Personal experience

2. The word of others (Authority)
Is It Illegal to Drive Barefoot in Your Home State?
Where Do We Get Our Facts?
Is It Illegal to Drive Barefoot in Your Home State?
2/3 of those surveyed believe it is illegal to drive barefoot

In truth, it is
to drive barefoot in all 50 States

It is arguably
than weaing flip flops or high heels
"Authority not only combines with experience to produce the raw material, the ‘facts,’ but also has to be frequently used instead of reasoning itself as a method of getting conclusions. For example, few of us have followed the reasoning on which even ten percent of the truths we believe are based. We accept them on authority from the experts and are wise to do so, for though we are thereby sometimes deceived, yet we should have to live like savages if we did not."
That's me. Barefoot on broken glass! Whoot.
Survey says...
We believe that shoes are required by law or health codes because that's what we've always been told

But the truth is there are very few laws* that require footwear and no health codes anywhere that require shoes
*A few towns in the United States require shoes in limited settings (e.g., on the boardwalk in Jersey Shore)
Do Shoes Affect the Way You Stand & Walk?
Full transcript