Shoes and Feet Final Exam BIOL313 Howell Liberty University

2/3 of young drivers surveyed believe it is

illegal to drive barefoot, when it is actually legal to drive barefoot in all 50 states and all US territories

-arguably safer than wearing flip-flops or high heels

there are only two sources for facts

1. personal experience 2. the words of others (authority)

-few of us have followed the reasoning on which even ten percent of the truths we believe are based

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

-there's more than 3000 municipalities in the USA and less than 12 have laws that require shoes in limited settings (boardwalk of Jersey Shore); none of them are states

shoes are tools and sometimes necessary but

-shoes absolutely hurt your feet

-shoes alter the anatomy of the foot (skeletal remodeling), the muscles of the foot, the fascia of the foot, and the biomechanics of standing, walking, and running

-shoes have both acute and chronic effects on the feet, ankles, knees, hips, and back

why do we wear shoes: protection from injury

-shoes do offer some protection from acute injuries, butacute risks are actually low, especially for experienced barefoot walkers/runners

->20,000 women a year are hospitalized because of high heels

-risk vs benefit?

-it's possible to stand on broken glass barefooted (Dr. howell did it)

why do we wear shoes: protection from injury (puncture)

-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, compared to 0% of the barefoot children

-frequently shoe particulate matter is embedded in the wound as well

why do we wear shoes: protection from germs

-many people believe shoes protect from germs but shoes are incubators for growing bacteria and fungi

-the leading cause of athletes foot and toenail fungus is shoes and socks, not going barefoot

-hookworm was a real threat in the US prior to indoor plumbing, but has since been eradicated

-"athletes foot does not occur among people who traditionally go barefoot"

Athletes foot

-most prevalent skin infection

-15% in general population (7:1 male:female)

-24% in male marathon runners

-6% female

toenail fungus

-2-3%

-2:1 male:female

-rare before 1900's

the foot sole has a high density of sweat glands, but

-closed toe shoes do not allow sweat to evaporate

-the dark, warm, and moist environment of the shoe creates a breeding ground for microorganisms, the cause of foot odor, athletes foot, and toenail fungus (feet don't stink, shoes stink)

why do we wear shoes: support

-podiatry is the only field of medicine in which a healthy body part is considered insufficient to perform its function without human intervention (support)

-support structures are generally recognized to weakened body parts

-casts are used to immobilize injured body parts to facilitate healing, but must be removed asap to prevent causing additional injuries

the shoe is a cast for the foot

the shoe: immobilizes the foot, reduces blood/lymph flow, causes atrophy of muscles, weakens ligaments tendons soft tissues, and alter the biomechanics of standing, walking, and running

not only does the shoe immobilize the foot, it immobilizes it in an

unnatural position

-compressed toes, toes elevated (hyperextended), arch permanently lifted, heel elevated

damaging features of 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

-cinching features (laces)

Hallux valgus

an abnormal deviation of the great toe (hallux) towards the other toes

-often used synonymously with bunion, but is not the same

bunion

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

bunions and hallux valgus are most common in

shoes wearing societies where there seems to be a genetic predisposition to these conditions

-irreversible damage caused by footwear (both hallux valgus and bunions)

hallux valgus is caused by

-skeletal remodeling

-photo compares the feet of a westerner with the feet of a Filipino native who has never worn shoes in 30+ years

-photo taken and published by Dr. Phil Hoffman in 1905

-this is not new information (shoes damage feet)

Hammer toe

-happens 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

-not known to be caused by flip-flops as commonly purported

ingrown toenails

often a result of excess pressure on the toes by shoes

Flatfoot has been called

-the silent epidemic that affects 25% of the population

-modern footwear immobilizes the foot, especially the arch, leading to muscle atrophy, weak ligaments, and fallen arches

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

shoes impede the

windlass mechanism of the foot by fixing the arch with an arch support, also shoes prevent the foot from changing length while walking

if u google how to treat flat feet, the causes, treatment, and prevention are

ALL FALSE (flatfoot is not genetic or caused by injuries, arch supports and surgery do not help treat flatfoot, and most cases are in fact preventable even though they say they aren't

Fallen arches are caused by

arch supports in shoes that weaken the muscles and ligaments that naturally support the arches

-fallen arches can be raised by walking barefoot

shoes harbor

pseudomonas bacteria

the majority of foot problems in Western culture is from the

overuse and abuse of shoes:

-athletes foot

-toenail fungus

-pseudomonas infection

-hallux valgus

-bunions

-ingrown toenails

-hammer toes

-fallen arches

-plantar fascitis (fasciosis)

-knee osteoarthritis

-hip/back pain

footwear is

ubiquitous in western culture/society

shoes must be considered when studying the biomechanics of

walking and foot health

shoes can alter/affect

-stance, posture, and ambulation (walking and running)

-feet, ankles, knees, hips, and spine

-skin of the feet

the problem are footwear isn't neccessarily just the shoe, but

-our shoe wearing habits

-people wear shoes when they are not necessary

-people wear shoes that are fashionable rather than functional (and they suffer negative consequences)

The narrow toe box of shoes

-reduce the efficacy of the great toe during push off

-eventually pushes hallux laterally (hallux valgus)

short toe box causes

hammer toe and ingrown toenails

the force during push off is

shifted laterally to the 2nd and 3rd toes

-the shift is present while wearing shoes and persists when shoes are removed in older folks

elevated heels cause

- a shift of the 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

-toes are kept hyperextended and the windlass mechanism is disengaged (permanently activated)

-engage muscles to keep the body from falling forward (triceps surae, gluteus maximus), pelvis tilted 15 degrees, curves in spine are exaggerated

body weight in heels is also

shifted forward in the knee; knee osteoarthritis is 4X higher in women than men

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

walk n' roll

-the elevated heel and toe spring convert the complicated stepping motions into a rolling motion

-foot is immobilized inside the shoe; little activity by intrinsic foot muscles leads to atrophy

-windlass mechanism, shock absorption, and spring action of arches dramatically reduced by immobilization and arch support

Plantar Fasciitis

-most common foot complaint in the US

-characterized by sharp heel pain, especially in the morning

-treatments include steroid injections, physical therapy, and orthotics, but the treatments rarely work because the patients keep wearing shoes

-iosis

dead tissue

plantar fasciitis

inflammation of the plantar fascia

plantar fasciosis

tissue death of the plantar fascia

permantly hyperextended toes (from toe spring, elevated heel, and arch support)

reduces blood perfusion of plantar fascia leading to necrosis (necrosis causes inflammation)

shoes and running

-modern running shoes possess: thick hard soles, soft padded insides, toe springs, elevated heels, arch support, and panel supports

-running shoes dramatically reduce tactile feedback from the sole of the foot

Shoes and running vs barefoot and running

-promote over-striding, over-extended knee, dorsiflexion, and heel striking

-barefoot running promotes flexed hip, knee, and ankle; flatfoot landing

Based on research by Daniel Leiberman (Harvard)

-running shoes create a sharp, transient ground reaction force (GRF) that is absent when barefoot

-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

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 "stitches")

running shoes almost always have a

-flared shoe sole (wider than sole of foot)

-this is designed to stabilize the foot, but it 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

growing up in shoes

-going barefoot to school was the norm in the US until the 1970s

-children should still go habitually barefoot

-the foot arches take 8-10 years to fully develop

-putting shoes on children is setting them up for foot failure

-spending childhood barefoot will reward adults with healthier feet for life