Are we born to run?
A biomechanical analysis of
barefoot/minimalist running and its
correlation to prevention of common
Jason W. Harnett
• Running in today’s society
• Evolution of running in humans
• Invention of the modern day running shoe
• Biomechanics of shod vs. barefoot/minimalist
running with analysis
• Common running injuries and causes
• Exercise prescriptions
• Case Study
• Culminating Activity
Running: todays society
• Today there are over 20 million runners in america that run
more than 100 times each year(SGMA, 2012)
• $2.46 billion spent on running shoes (SGMA, 2012)
• Over $1 billion dollars in charity raised (SGMA, 2012)
Running and Injury Rates
• 79% of runners
running over 12 miles
a week will get
injured at some point
within a 12 month
span (Van Gent et al.
Evolution of Running
• Are we born to run?
• Geologic evidence suggests a climate change over 2 million
• Woodlands disappeared, savannahs resulted (Hazarika, 2007)
• Austrailopithecus were frugivorous (mainly ate fruit) and were
anatomically designed to walk and climb trees.
• Extinction due to environmental shift spawned the
evolvement of home erectus about 2 million years ago
• Homo erectus – first hominid anatomically designed to run.
• Primarily a meat eater
• First throwing weapon was the spear dating back 500,000 years
ago (Wilkens et al, 2012)
• Persistence hunter – chasing prey to the point of exhaustion
Anatomical evidence we evolved to run
Why are we getting injured?
• If we evolved to run, it is counterintuitive that
we get injured doing it….
“Its gotta be the shoes!” SpikeLee
Evolution of the Running Shoe
• First shoe discovered similar to the huarache
Evolution of the Running Shoe
• 1890s – Reebok
Evolution of the Running Shoe
• 1925 – Adidas
Evolution of Running Shoe
• 1963 – Asics
Evolution of running shoe
• 1972 – Nike
Evolution of the running shoe
• Modern day running shoe
Do shoes prevent injury?
• Van Gent study confirmed that injury rates have not seen any
significant improvement since the 1970s
• How running shoes are commonly prescribed
• Motion control
Marine Corps Study (Knapik, 2010)
No study has ever verified running shoes reduce injuries!
Modern Shod Runner
Barefoot vs. Shod landing
Forefoot striking Heel Striking
• Running in Shoes
• 75% of shod runners
are heel strikers
Kenyan running in Shoes
High Heeled Shoes?
Shoes alters biomechanics, almost forces you to
land heel first (Leiberman, 2010)
• 75-91%Landed with a
• Could this be the
connection for injury
Biomechanics of Running
• What is
• Analysis of Shod
running vs. barefoot
or minimalist running
• F = ma
• T = fd
Newtons 3rd Law
• For every action,
there is an equal and
• Ground Reaction
Forces of Heel Striking (barefoot)
Forces of forefoot striking (barefoot)
Forces of heel striking (shod)
Forefoot striking in shoes
Where We land…..
• Heel strikers had Longer stride length than forefoot runners
What is Torque?
Torques on the Joints
• Forefoot runners knee torques are reduced in flexion, internal
rotation and varus (Kerrigan 2009, Standifird 2012)
• Decreased stride length = decreased hip adduction and
extension moment of knee (Heiderscheit 2011)
• Morley et al (2010) showed a decrease of >5 degrees in
calcaneal eversion range and velocity when forefoot striking
= decrease pronation.
Why the increased Pronation?
• Heel strikers pronate more because there is no musculature to
attenuate the forces.
• Forefoot strikers can control their pronation with the eccentric
contraction of the tibialis posterior along with the transfering
of forces to rotational motion of the talocrural joint.
• In other words, heel striking may cause excessive pronation
because impact forces cannot be transmitted through a
mobile ankle to the gastroc-soleus complex.
• Forces are transmitted by the subtalar joint, leading to rapid
pronation forces. (Morley, 2010)
Lateral Heel Counter
• Increased pronation=
• Internal tibial
• Increased valgus =
• Increased hip
How to tell is you are over
• Cadence = Amount of steps per minute
• Ideal number is 180 per minute
• Count number of steps in 6 seconds x 10
Video Analysis – (istherea properformtorunning?)
• Can you find 2 biomechanical deficiencies that may be contributing to this runners injuries?
• Heel striker = increased transient force (more force in short
amount of time)
• Over strides = cadence of 160 steps per minute = increased
torque on joints
Common Running Injuries
• Plantar Fasciitis
• IT Band Syndrome
• Patellofemoral Pain
• Shin splints
• Stress Fractures
• Plantar Fasciitis is caused
from weak intrinsic foot
more stress on the
fascia, and flexibility
deficits in the posterior
calf. (Kibler, 1991)
strengthens intrinsic foot
lengthens the posterior
calf muscles (Robbins,
IT Band Syndrome
• The development of
iliotibial band syndrome
appears to be related to
increased peak hip
adduction and knee
• According to
increased stride length
commonly seen in shod
runners increases both
hip adduction and
internal torque of the
Patella Femoral Pain
• Excessive impact shock during heel strike and at the
propulsion phase of running may contribute to an increased
risk of developing PFP (Thiis, 2008).
• Foot pronation causes a compensatory internal rotation of
the tibia and femur which upsets the patellofemoral
mechanism (Zappala, 1992).
• According to Moen
pronation is linked
with medial tibial
• Shod and heel
and velocity (Morley
et al. 2010)
• Studies suggest that
runners with higher
than normal tibial
rates are at increased
risk for tibial stress
running reduces the
rate of loading
barefoot/minimalist is not for
• Surgeries that
• Other major
When to recommend change in
form or footwear?
When runners have tried everything and are still suffering from
injuries and other symptoms
When runner are serious about making a change…it requires
time and dedication
If patients are healthy and compliant, its easy to get injured….
What about people with flat feet and orthotics?....Robbins study
proves feet can be strengthened and arch heights increased.
• There have been several studies that suggest running barefoot
or in minimalist can increase injury rate
• Jenkins 2011 meta-analysis study: Flawed studies, no formal
transitional training ever took place
• Runners were given minimalist shoes without assuring they
knew how to properly use them.
Transitioning Running Form
• Shoes have essentially weakened our feet by shortening the
Achilles and weakening the intrinsic and extrinsic foot muscles
and which possibly increases injury. (Robbins, 1987)
• 4x more likely to develop flat feet wearing shoes (Rao, 1992)
• Strengthening and stretching program must be implemented
before attempting to run with a new gait
How to transition
• Shod to minimal/barefoot……Start Slow!
• 4-6 month process
• Most people have been shod or heel strike runners their
Transition Phase - Flexibility
• Assess motion at the ankle and forefoot
Foot and Ankle Strengthening
• Flexor Hallicus Brevis and Flexor Digitorum Brevis
Foot and Ankle Strengthening
Intrinsic Foot Musculature
• Single Leg Balance
• Perform with
• Ball Toss
• Eyes Closed
• Foam Mat
Group Case Study
• 34 year old male recreational runner whom recently began
training for Flying Pigs Marathon. He comes to you
complaining of anterior knee pain.
• Formulate groups and discuss questions you would ask, tests
and measures you would conduct, and exercise prescription
and education you would advise this particular patient.
• Let’s experience the difference!!
• Audience will run shod for 30 seconds on treadmill
• Then run barefoot for 30 seconds
• Note the differences you personally feel
• Scientists agree that we have evolved to run
• Shoes alter biomechanics of running
• Injury rates have not changed in over 30 years and no study
confirms shoes prevent injuries
• Heel striking increases rates of loading and over-striding,
which increases torques on joints
• Both shoes and heel striking encourage excessive pronation
• Shoes are proven to weaken intrinsic foot musculature and
shorten Achilles tendons
• There is enough anecdotal evidence to suggest these facts
may contribute to common overuse running injuries
•Could less be more?????
• 26 bones
• 33 articulations
• Arch that 4 muscle
• Several tendons and
• “The human foot is a
engineering and a
work of art.”
- Leonardo di Vinci
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