Barefoot vs. Shod Running - Physical Therapy and Rehabilitation ...

Barefoot vs. Shod Running:
An Evidence-Based Review of
Ground Reaction Forces at
Initial Contact
Ryan Johnson, MS, DPT(c)
PT 209-910

Clinical Problem:
• Currently there is a significant lack of
knowledge surrounding efficient running
– What running patterns are most beneficial?
– Is a heel strike really the best and most healthy
running pattern?
– What are the effects of footwear?
– How can physical therapy assist runners to reduce
injury and increase performance?

Significance of Problem:
Number of
PEOPLE
interested in
BF running
Growing Trend
(Fitzgerald M, 2010)
Number of
PATIENTS
interested in
BF running

Physical Therapy Relevance:
Clinicians need Knowledge
Research provides
clinicians with an
understanding of the
biomechanics behind
different running
patterns
Clinicians are able to
make “evidencebased”
decisions for
each patient

Physical Therapy Relevance:
Researchers need Inspiration
Clinicians synthesize
knowledge to make
clinical decisions
Pose questions to
researchers to
stimulate future
studies

Purpose of Review
Compare Shod vs. Barefoot (BF) Running
through analysis of
Ground Reaction Forces (GRF)
http://www.youtube.com/watch?v=9itkEkcQ8WM&feature=related

Theoretical Constructs
• Repetitive impact forces through the body may
be detrimental (landing hard after a jump or
when stepping off curve, working all day with a
jackhammer, FOOSH, etc.).
(Sangha et al. 2000; Hewett et al. 2005; Hreljac et al. 2004; Schamberger et al. 2002)
http://gallery.photo.net/photo/3069741-lg.jpg
http://c.photoshelter.com/img-get/I0000KnYFMTjp0dg/s

Theoretical Constructs
• The ground reaction force (GRF) upon impact,
“is considered to be the most basic element
which causes running related injuries.”
http://jpthermt.com/wp-content/uploads/2010/07/running-injury.jpg
(Robbins et al. 1987)

Theory behind BF Running
• Current scientists, paleontologists, anatomists and
physiologists have been challenging “traditional”
knowledge on running biomechanics
• Daniel E. Lieberman, PhD
• Irene Davis, PhD, PT, FACSM
• Madhusudhan Venkadesan, PhD
• Mark Bishop, PT, PhD, CSCS
• Craig Richards, PhD
• R. Squadrone
http://static.technorati.com/11/02/04/26399/wo
man-running221.jpg

Theory behind BF Running
• Hypothesizing that landing on the mid-foot
rather than a heel-first strike may:
– Conserve energy
– Reduce impact transient forces (Liberman DE et al., 2010)

http://www.ceessentials.net/images/critiqueLowerExtremity/image216.jpg
Anatomy and
Theoretical Constructs
http://www.carifinonline.com/wp-content/uploads/2010/01/heel-strike-compare.jpg

Proposed Benefits to BF Running
The following have been postulated as possible
benefits to BF running:
• Decreased VO 2 consumption
• Increasing the strength of the ligamentous and muscular
support of the arch
• Increased proprioception
• Decreased risk of lower extremity injury, including:
– Lateral Ankle Sprains
– Plantar Fasciitis
– Medial Tibial Stress Syndrome
– Etc.
(Hanson et al. 2011; Squadrone et al. 2009; Jungers et al. 2010;
Robbins et al. 1989; Divert C, 2005; Divert C, 1985; Warran et al. 1987)

And Lastly….
It has been proposed that BF running can
decrease the transient ground reaction force
experienced at initial contact (Liberman et al., 2010)
http://www.stgeorgerunningcenter.com/wp-content/uploads/2011/05/running-barefoot.jpg

Background
• Have running shoes ever been proven to
reduce the risk of injury?
• Answer
– No… There has never been a peer review article
published which showed a statistically significant
reduction in injury rate for those individuals
wearing shoes. (Richards et al., 2008)

Background
• Are running related injuries a serious problem
in the medical community?
• Answer:
– Yes… every year 65-80% of all runners suffer an
injury. (McDougall, 2009; Warran et al. 1987)

GRF at initial
contact
(IC-GRF)
Terms Defined
Passive Peak
(Impact Transient)
Ground Reaction Forces (GRF)
Active Peak

Heel Strike (HS)
or
“Rear Foot
Strike” (RFS)
http://4.bp.blogspot.com/_JadSUXnX75Q/S3aD2iNRnsI/AAAAAAAAAT8/sl
8pbmfVQ70/s320/heelstrike.jpg
Terms Defined
Non-Heel Strike
(NHS)
Mid-foot/
Forefoot Strike
(FFS)

Gap in the Literature
• There has never been a systematic review or
meta-analysis addressing the relationship of
IC-GRF to both shod/BF and location of first
contact.
http://www.superstock.com/stockphotos-images/1598R-38363

• Primary:
QUESTIONS
– While running, what are the differences in IC-GRF
between BF and shod conditions?
• Secondary:
– While running, what are the differences in IC-GRF
between HS vs NHS running patterns?
Both are background questions

Hypothesis & Null Hypothesis
H 0: H A:
There is NO statistically
significant difference in
IC-GRF between:
There IS a statistically
significant difference in
IC-GRF between:
1) BF and Shod running conditions
2) HS and NHS running patterns

Search Procedures
• Databases (number of results)
– PubMed (43)
– CINAHL (17)
• Search Terms:
– “barefoot running”
– “running barefoot”
– “run barefoot”
– “jog barefoot”
– “barefoot runner(s)”
• Dates included in search: 1980 – 2011
– Last search performed: April 30 th , 2011

All articles were reviewed against the following criteria
Inclusion Criteria Exclusion Criteria
1. Must measure GRF with a
force plate or 3D force
transducer treadmill**
2. Must compare BF running
to Shod running
3. Subjects were “normals” or
“athletes” with no
pathology present
4. IC-GRF data must be
available
**(Low et al., 2010; Mainwald et al., 2008; Belli et al. 2001)
1. Articles written in
languages other than
English
2. Only abstract was
available
3. Subjects were less than
16 years old
4. GRF data was not able to
be correlated with body
weight of subjects

Secondary reviewer
confirmed that the 7
studies met the inclusion
criteria

All studies: level of
evidence 2b
Summary of Included Studies

Effect Size
Calculated
Statistics
BF vs. Shod running IC-GRF
Primary Question
High
Q-Statistic
Random
Effects Model
Recalculated

Barefoot vs. Shod
Results
Random Effects Model
Effect Size: -1.72
Large Effect Size
CI (-3.41, -0.04)
Significant
Q-Statistic
121.92

Statistics
HS vs. NHS running patterns IC-GRF
Evaluate for
difference between
HS and NHS means
Secondary Question
z-test

Study
Hammill
et al.
Lieberman
et al.
Squadrone
et al.
Divert
et al.
Baur
et al.
De Wit
et al.
Dickinson
et al.
# of
Subjects
HS
Mean
Results
z-test comparing HS and NHS
Heel Strike Non-Heel Strike
HS
SD
10 1.59 0.31
26 1.74 0.45
8 1.72 0.4
35 1.70 0.03
14 1.62 0.15
9 1.9 0.3
6 1.39 0.67
Study
Hammill
et al.
Lieberman
et al.
Squadrone
et al.
# of
Subjects
NHS
Mean
NHS
SD
10 1.40 0.31
26 0.58 0.21
8 1.62 0.4
BW IC-GRF
Mean HS: 1.67
Mean NHS: 1.20

Results
z-test comparing HS and NHS
HS NHS
1.67 1.20
Z-test: (95% CI)
Upper CI: 0.85
Lower CI: 0.08
Statistically
Significant
Difference

Results:
H 0:
1) There is NO statistically significant difference
in IC-GRF between BF and Shod running
conditions
2) There is NO statistically significant difference
in IC-GRF between HS and NHS running
patterns

Discussion
1. Significant heterogeneity of data
2. Possible causes for reduced IC-GRF
3. Implications of reduced IC-GRF
http://www.runningnut.com/wp-content/uploads/2010/09/barefoot-runner.jpg

This image cannot currently be displayed.
Discussion
BF/Shod Comparison
- Number Sample of Size Strides Difference Measured

Discussion BF/Shod Comparison
Possible Explanations for Heterogeneity of Data
Distance run during data analysis
• 6.5 meters vs. 1.2 kilometers
http://100daysofmadness.com/wpcontent/uploads/2010/11/Son-Running-Barefoot.jpg
Experience of Barefoot Runners
• Adaptations to BF running
could take several weeks
(Robbins et al. 1987, 1989 and 1993)
http://farm5.static.flickr.com/4012/4311804925_32cebc0631_o.png

Discussion BF/Shod Comparison
Possible Explanations for Heterogeneity of Data
– Experience of Barefoot Runners
• De Wit et al. utilized only habitual shod runners in both BF
and Shod conditions
– Smaller ES (-0.33)
http://communities.canada.com/calgaryherald/blogs/calgaryrunner/archive/2010/07/07/rac
e-preview-canadian-mountain-running-championships.aspx

Discussion BF/Shod Comparison
Possible Explanations for Heterogeneity of Data
– Experience of Barefoot Runners
• Squadrone et al. utilized experienced BF runners in both shod
and barefoot conditions
– Smaller ES (-0.25)
http://www.barefootrunning.fas.harvard.edu/3RunningBeforeTheModernShoe.html

Discussion BF/Shod Comparison
Possible Explanations for Heterogeneity of Data
– Experience of Barefoot Runners
• Lieberman et al. utilized habitually shod vs. habitually BF
runners
– Larger ES (-3.44)
http://www.healthynomics.com/wp-content/uploads/2009/08/barefoot-running1.jpg

Discussion
The BF condition & FFS running pattern
http://barefootted.com/uploaded_images/Sportsllustrated
Barefoot01-719926.jpg
decrease IC-GRF
Causes?
http://gearjunkie.com/images/1825.jpg

Discussion
Causes of Decreased IC-GRF
• Superior neurosensory feedback preparing musculature
for next stride (Kurz and Stergiou, 2004)
http://www.ransacker.co.uk/wp-content/uploads/2010/08/A-barefoot-runner-in-Hyde-001.jpg

Discussion
Causes of Decreased IC-GRF
BF condition tends to equal NHS running pattern
(Lieberman et al. 2010; Squadrone et al. 2009; Divert et al. 2005)
http://4.bp.blogspot.com/_JadSUXnX75Q/S3aD2iNRnsI/
AAAAAAAAAT8/sl8pbmfVQ70/s320/heelstrike.jpg

Stretching of arch
Discussion
Causes of Decreased IC-GRF
• first half of FFS
• second half of RFS
No energy return and
no dampening of forces
(Lieberman et al.
2010)
http://www.youtube.com/watch?v=r6YhVN_YIUk

Change in stride length
(Lieberman et al. 2010; Squadrone et al,
2009;
Divert et al, 2005; De Wit, 2000;
Edwards et al. 2009, etc.)
Discussion
Causes of Decreased IC-GRF
Greater vertical compliance,
leading to lower rate of loading
(Lieberman et al. 2010)

Discussion
Reduced IC-GRF
Implications?
http://signaturestyleblog.com/wp-content/uploads/2011/03/girl_running_on_beach.jpg

Harm and Cost Effects
• Not examined in any primary
article
– BF running reduces IC-GRF,
theoretically there could be a
reduction in stress-induced
injuries
– If stress induced injuries are
reduced, theoretically health care
costs could be reduced
http://ravenessences.files.wordpress.com/2011/03/barefo
ot_tefe_dancing.jpg?w=218&h=247

Possible Precautions/Contraindications
• Osteoporosis/Osteopenia
• Peripheral Neuropathy
• Peripheral Arterial Disease
• Rigid midfoot
• Cold/Hot Temperatures
• Obstacles on ground
– Broken glass
– Nails
– Needles
(Squadrone et al. 2009; Jenkins and Ross, 2011)
http://shodless.com/wp-content/uploads/2010/01/michael_sadler_barefoot_winter.jpg

Shoes for forefoot strike?
• Vibram Fivefingers
• Tarra Plana Evo
• Merrell Trail Glove
• New Balance Minimus
• Kigo Edge
• Nike Free
http://kayakshed.blogspot.com/2010/07/
kigo-improves-its-minimalist-shoes.html
http://www.vibr
amget.com/ima
ges/729013%5B
1%5D.jpg
http://www.treeh
ugger.com/Terraplana-evobarefoot-runningshoe-photo.jpg
http://www.sho
pnewbalance.co
m/products/MT
10GY_lg.jpg
http://runningti
mes.com/rt/ima
ges/201012/Trail
Shoe_Merrell-
Trail-Glove-.jpg
http://www.nike
freerunshop.co
m/images/nike_
free_run_men_b
lack_red.jpg

Implications for Practice
http://www.voxy.co.nz/userfiles/running%20barefoot%20shoes.jpg
• Educate patients on
evidence available at this
point
• Decreased IC-GRF with BF
running
– Effect size -1.72 = 41% BW
• NHS also reduces IC-GRF
• PT interventions?

Limitations
• Heterogeneous studies
– Heterogeneous subjects
– Inconsistent distance run in experiment
– Small sample sizes
• Developing area of research
– HS vs NHS required
• Only included articles in English
• Not enough data to determine interaction
effect between BF and NHS

Directions for Further Research
• Define normative values for specific sub-groups
of runners
• Further examine differences between habitually
shod and barefoot runners
• Investigate whether minimalist shoes mimic the
positive aspects of BF running
• Investigate BF vs Shod running patterns at longer
distances

Directions for Further Research
• Investigate injury rates in both BF and shod
running populations
• Investigate which body types and structures
are most successful for both shod and
barefoot running
• Role of BF/NHS running in injury prevention

Conclusions
• Statistically Significant
difference in IC-GRF between
BF/Shod and HS/NHS
• Further research needs to be
completed before making
large clinical decisions
• This literature review is just
one step towards
understanding the vast
differences between running
barefoot and running shod
http://www.goodhousekeeping.com/cm/goodhousekeeping/i
mages/qZ/ghk-canyon-spotting-lg.jpg

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• Wolf S, Simon J, Patikas D, et al. Foot motion in children- A comparison of barefoot walking with shod walking in conventional and flexible shoes. Gait
Posture. 2008; 27(1):51-59.
• American Podiatric Medical Association Website: http://www.apma.org/MainMenu/News/MediaRoom/PositionStatements/APMA-Position-
Statement-on-Barefoot-Running.aspx
• Yessis M. Explosive Running: Using the Science of Kinesiology to Improve Your Performance. McGraw-Hill, New York, 2000.

Thank You
• Diane Allen, PT, PhD
• Arlene McCarthy, PT, DPT, MS, NCS
• Ali Legakis, MS, DPT(c)
• Emily Hellmuth, MS, DPT(c)
• Pete Rumford, MS, DPT(c), CSCS
• Sara Tanza, MS, DPT(c)
• Naomi Hosking, MS, DPT(c)
• Janeen Gray, MS, DPT(c)
• UCSF/SFSU, DPT Class of 2011

Videos if Time Allows
• Barefoot Kenyan runner
• http://www.youtube.com/watch?v=pgkWhca
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