AMAA15_Min to Max Shoes.pptx

4/16/15
An Update on
Running Footwear:
From Minimal to
Maximal Shoes
Healthy People 2020
Exercise is MedicineTM
Irene S. Davis, PhD, PT, FAPTA, FACSM, FASB
Up to 79% runners will
sustain an injury in a given
year
46% will be recurrences
Van Ghent, 2007
~20 million Americans run
Professor, Harvard Medical School
Director, Spaulding National Running Center
Mismatch Theory
We are not living the lives our bodies were designed for
Food, Air, Activity level
Cause of many of the illnesses today
Diabetes, Obesity, CV disease
DysEvolution of the Runner!
Are we doing something wrong?
Where Running Began
Well- Designed Feet
Australopithecus
Medial foot
~ 2 Million
yrs ago
Nuchal Ligament
Larger joint surfaces
Shorter femoral neck
Expanded Glut Max
Long Achilles
Plantar Arch
Bramble and Lieberman, 2004
5/26 Markers of
Endurance Running
26 bones, 33 jts with
6 dof of movement
4 layers of arch muscles
Rigid Lever, Mobile Adapter, Spring
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So why was footgear developed?
The human foot is
well-suited for
walking and running
locomotion
Earliest examples of footgear sagebrush bark sandals found in
caves near Fort Rock, Oregon
under a layer of volcanic ash
dating back 10,000 years.
The foot surface is smooth and
they were held on by straps over
the instep.
SF Stewart, 1972
Prime function of the earliest sandals was protection of the sole.
History of Running Shoes
History of Running Shoes
1963: Asics Onitsuku Tiger
Imported to the US by Phil Knight.
Introduced the cushioned heel.
1890’s: J.W. Foster and Sons
(now Reebok) introduce the first
running shoe.
1972: Phil Knight leaves Asics to form
Nike. Nike began producing their own
version of the Tiger: the Nike Cortez.
1917: The advent of vulcanized
rubber leads to the first “sneaker”,
the Keds Champion
Nearly 40 yrs later: The Modern Running
Shoe – elevated cushioned heel, stiff heel
counter, arch support, high medial midsole
density
1925: Adi Dasler (now Adidas)
introduces customized shoes
In 4 Short Decades…
How did this happen?
Jeff Johnson – Nike 1965-1983
50-60’s
Ran in thin-soled canvas shoes on hard surfaces
Well-trained - Had ‘legs of steel’ –reports that injuries were rare
70’s
Running Boom – more inexperienced runners – beginning of
cushioned shoes (Cortez)
RW published first two running injury surveys
1971 800 runners
knee injuries 17.9% of runners
1973 1680 runners
knee injuries 22.5% of runners
Cavanagh published results of injury clinic
1979 974 inj. runners knee injuries 30% of injuries
2014
1972
2010
(Taunton 2002 – 2000 inj. runners – knee injuries 42% of injuries)
Early 80’s
The HORMONAL Shoe
Asics GEL-KAYANO 16
Nike invites Drs. Steve Subotnik, Harry Hlavick, Dennis Vixie prominent sports DPMs. They encouraged more motion control
and cushioning
“Adjusts its stiffness to your time of the month”
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Next Question…..
Do Modern Running Shoes
Contribute to Injury?
2010
Motion
control
Stability
Cushioning
Conclusions
‘Assigning shoes based on the shape of the
plantar foot surface had no influence on injuries’
Shod Running Mechanics
RFS
89%
Vertical Impact Loads and Injuries
2500
2000
X
Imp
Pk
1500
1000
Loadrate
500
MFS
10%
0
0
25 50 75 100 125 150 175 200 225
Time (ms)
Impact loading was greater in those with hx of
Tibial stress fx, Plantar fasciitis, PFP
FFS
1%
Altman et al., 2009
Larson et al., 2011
Peak Forces were not!
Difference between Shod and BF Running
Milner et al, 2006
Bowser et al, 2010
Pohl, 2009
Recent Changes
2005
2009
2010
Reduced vertical impacts and lateral forces in BF
Shorter strides, less work knee, more at ankle
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What Constitutes Minimal Footwear?
Minimal Footwear Running Mechanics
BF
MRS
No motion control
No cushioning
Shoes of Ron Hill
who won 1960
Boston Marathon
TRS
Zero drop
No arch support
No midsole
Squadrone and Gallozzi, 2009
8 Healthy Habitual BF Runners
What else is at risk?
Injury Reports began in 2011
First Report – Guiliani et al, 2011
Proper
2 runners (in Vibrams) with 2nd MT Stress Fx
No transition program
FFS
Second Report – Salzler et al, 2012
10 injured runners following Vibram running
Avg transition time = 0.7 months
Injuries occurred in the first few months
9/10 were stress fx; 8/9 to the metatarsals
Third Report – Ridge et al, 2012
10/19 Vibram runners developed bony edema
Most often occurring in the MT
2 stress fx (calcaneus and MT)
Loosely structured transitioning program
Transition requires
fortification of these
structures!!!
gastroc
achilles/
soleus
post. tib.
Arch/plant.
fascia
metatarsals
Partial Minimal Shoes
Partial Minimal Shoes (PMRS)
PMRS
PMRS
Min motion control
Min cushioning
Min drop
Min arch support
Min midsole
TRS
BF
Partial minimal shoes more similar to traditional shoes than BF
With regards to stride length and impacts
Bonacci et al, 2013, Willy and Davis, 2012
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“I read the book, bought the shoes and now am a FFS!”
It is difficult to judge one’s own FS pattern in (even
low) cushioned shoes
Goss et al, 2012
Goal of Minimal Footwear: Mimic BF
Results
“The partial minimalist shoe reported a significantly higher rate
of injury incidence throughout the 12-week period”
Goal of Minimal Footwear: Mimic BF
Partial minimal shoes do not
Effect of Lever Arms in Traditional Shoes
But What about Hoka One One Shoes ?
a
VGRF
VGRF
LGRF
Pronation is greater in shoes due to longer lever arms
Bonacci et al, 2013
Impact Peaks and Load Rates similar between conditions (n=1)
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…….Why is this?
Other Mechanical Benefits of Minimal Footwear
$10
$65
McNitt-Gray et al, 2006
Bishop et al, 2006
Stiff mat – Soft Landing
Soft mat – Stiff Landing
More cushioning – Stiffer knee
5 months of MRS
Increase in Muscle Size Ferris et al, 1988, 1999 –running
You actually land harder when you land on soft surfaces!
Bruggemann et al, 2005
Miller et al, 2014
Strong Feet are Healthy Feet !!
The Arch is the Foot Core!!
Small X-sectional areas
Short moment arms
Stabilizers vs prime movers
12 wk program
Increase in Arch Stiffness
Increase in Abd Dig Min
Medial foot
You need foot stability for
proper foot mobility!
Plantar Fasciitis – up to 25% foot injuries!!
Intrinsic Foot Muscles McKeon et al, 2014
They will become strong if we increase the
demand on them!
We decondition them with chronic support!
Permanent Tx
For Foot Pain
Permanent Tx
For Neck Pain?
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Is forefoot striking in minimal shoes a trend?
Take Home Message
1.  Modern running shoes (including highly cushioned
shoes) have altered the way that we run
2.  True minimal shoes (no cushioning) most closely
mimic BF running which we were designed for but
place altered demands on the lower extremity
Proper transition to this footwear is needed
3. If you are going to remain a RFS, wear neutral
cushioned shoes
Circa 1970
Or a return to running more naturally?
Recent References
JOSPT Special Issue: Running,
October, 2014
Thank You Special Issue: Barefoot and Minimal
Footwear Running, June, 2014
Spaulding Na1onal Running Center www.runsnrc.org 7