[
research report
]
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JOSEPH J. KNAPIK, ScD1 • DANIEL W. TRONE, PhD2 • JUSTE TCHANDJA, MPH3 • BRUCE H. JONES, MD1
Injury-Reduction Effectiveness
of Prescribing Running Shoes
on the Basis of Foot Arch Height:
Summary of Military Investigations
T
he first clinical use of footprints (plantar shapes) may be
attributed to Colonel R. I. Harris and Major T. Beath, who
used them to evaluate foot problems in Canadian soldiers.
Recruits and soldiers stepped on a rubber mat that provided
a visualization of their footprint and the
amount of static weight-bearing pressure
exerted on different parts of the foot.19,35
TTSTUDY DESIGN: Secondary analysis of 3
randomized controlled trials.
TTOBJECTIVE: Analysis of studies that examined
whether prescribing running shoes on the basis
of foot arch height influenced injury risk during
military basic training.
TTBACKGROUND: Prior to 2007, running maga-
zines and running-shoe companies suggested that
imprints of the bottom of the feet (plantar shape)
could be used as an indication of foot arch height
and that this could be used to select individually
appropriate types of running shoes.
TTMETHODS: Similar studies were conducted in
US Army (2168 men, 951 women), Air Force (1955
men, 718 women), and Marine Corps (840 men,
571 women) basic training. After foot examinations,
recruits were randomized to either an experimental
or a control group. Recruits in the experimental
group selected or were assigned motion-control,
stability, or cushioned shoes to match their plantar
shape, which represented a low, medium, or high
Subsequently, these footprints were used
to determine a number of clinical indices,
which included plantar shapes classified
foot arch, respectively. The control group received
a stability shoe regardless of plantar shape.
Injuries during basic training were assessed from
outpatient medical records.
TTRESULTS: Meta-analyses that pooled results
of the 3 investigations showed little difference
between the experimental and control groups in
the injury rate (injuries per 1000 person-days)
for either men (summary rate ratio = 0.97; 95%
confidence interval [CI]: 0.88, 1.06) or women
(summary rate ratio = 0.97; 95% CI: 0.85, 1.08).
When injury rates for specific types of running
shoes were compared, there were no differences.
TTCONCLUSION: Selecting running shoes based
on arch height had little influence on injury risk in
military basic training.
TTLEVEL OF EVIDENCE: Prevention, level 1b.
J Orthop Sports Phys Ther 2014;44(10):805-812.
Epub 25 August 2014. doi:10.2519/jospt.2014.5342
TTKEY WORDS: footprints, foot type, pronation
as high arched, broad (low arched), and
normal,34,36 as shown in FIGURE 1.
Perhaps the first to apply plantar
shapes to running shoes was Dr Peter
Cavanagh, who recommended that static
footprints, in conjunction with dynamic
foot flexibility measurements, could be
used as part of a 10-point plan to find the
most appropriate running shoe.8,10 Subsequently, several running-shoe authorities
in the popular running magazine Runner’s World suggested that plantar shapes
could assist in determining if individuals
overpronated, underpronated, or had
normal pronation during running.9,12,13
Beginning in the late 1980s and into
the 2000s, running shoes were largely
classified based on their intended purpose and related to plantar shapes. It was
assumed that plantar shapes were reflective of foot arch height and could assist in
selecting individually appropriate types
of running shoes, with the goal of reducing the likelihood of injury.2-5,14,30,39 Individuals with a foot shape reflecting a low
arch were presumed to have greater rearfoot and midfoot mobility that allowed
the foot to pronate excessively during the
stance phase of running. For these individuals, “motion-control” shoes were rec-
US Army Institute of Public Health, Portfolio of Epidemiology and Disease Surveillance, Aberdeen Proving Ground, MD. 2Naval Health Research Center, San Diego, CA. 3559th
Medical Group, Joint Base San Antonio, Lackland, TX. This study was funded by the Defense Safety Oversight Council. The authors certify that they have no affiliations with or
financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article. The views expressed herein are the
views of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense, or the US government. Address correspondence to Dr Joseph
Knapik, US Army Institute of Public Health, Portfolio of Epidemiology and Disease Surveillance, ATTN: MCHB-IP-DI, Aberdeen Proving Ground, MD 21010. E-mail: joseph.j.knapik.
ctr@mail.mil t Copyright ©2014 Journal of Orthopaedic & Sports Physical Therapy®
1
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[
ommended, because it was assumed that
these shoes could control excessive foot
motion. Individuals with a plantar shape
reflecting a high arch were assumed to
have rigid or inflexible feet that impacted
the ground with greater force and did not
pronate sufficiently. These individuals
were directed toward “cushioned” shoes,
which presumably increased shock absorption by providing for more pronation
and cushioning to soften ground impact.
Individuals with a foot shape reflecting
a normal arch height were assumed to
impact the ground with less force and
to have an appropriate amount of foot
pronation. A “stability” shoe, which was
presumed to have moderate cushioning
and motion-control characteristics, was
recommended for these individuals.32
Prior to 2007, the military services
had generally followed the recommendations of the shoe companies. In fact,
many military post exchanges had wall
displays advertising various types of
running shoes categorized by foot shape
(FIGURE 2). During basic training inprocessing, new recruits could select or
were assigned a running shoe based on
the plantar shape of their foot. However,
whether shoes based on foot arch height
reduced injuries had not been tested in
a randomized controlled trial. Consequently, the Military Training Task Force
of the US Department of Defense Safety
Oversight Council requested that this be
examined in the military services, and
studies were subsequently conducted in
the Army, Air Force, and Marine Corps
basic training.22,26,27
The purpose of this paper was to
analyze and summarize the data from
previously published basic training
studies that examined the effectiveness
of assigning running shoes on the basis of plantar shape, assumed to reflect
foot arch height, in reducing injury. For
this purpose, we performed a secondary
analysis of the data from 3 randomized
controlled trials.22,26,27 Our goal was to
fully synopsize the results of the investigations and to provide evidence-based
conclusions.
research report
]
FIGURE 1. Plantar shapes showing high (A), low (B), and normal (C) arch heights.
FIGURE 2. A typical display of running shoes in a military post exchange, showing the shoes based on their
purpose and plantar shapes.
METHODS
I
n 2007, independent studies were
conducted in Army, Air Force, and Marine Corps basic training. The design of
the 3 studies was identical. Recruits were
randomized into either an experimental
or control group and trained side by side
in the same military units. The recruits
in the experimental group were assigned
motion-control, stability, or cushioned
running shoes, based on their plantar
shape, which represented a low, medium,
or high foot arch, respectively. The recruits in the control group were provided
with a stability shoe regardless of plantar
shape. In the Air Force and Marine Corps
studies, 3 models of New Balance shoes
were used, 1 matching each foot type. The
Army study included 19 different models
of shoes from 5 different shoe companies,
but shoes for the recruits in the experimental group were still assigned based
on plantar shapes. The shoe brands and
models used in each study are shown in
TABLE 1.
All recruits’ plantar shapes were
evaluated by having them step onto
the acrylic surface of a device shown in
FIGURE 3. Recruits were instructed to
stand with equal weight on each foot.
The device contained a mirror that reflected the underside of the foot, thus
providing a visual image of the footprint
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Running Shoes Used in the
Military Footwear Studies
TABLE 1
Control Group
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Experimental Group
Service
Motion-Control Shoe
Stability Shoe
Cushioned Shoe
Stability Shoe
Army26
Asics Gel Foundation 7
Brooks Addiction 7
Saucony Grid Stabil 6
New Balance 857*
Asics Gel 1120
Asics Gel 2120
Brooks Adrenaline GTS6
Brooks Adrenaline GTS7
Nike Structure Triax
Nike Air Max Moto*
Saucony Grid Omni 5
New Balance 717
New Balance 767
Asics Gel Cumulus
Brooks Radius 6
Nike Air Pegasus
Saucony Grid Trigon 4
New Balance 644
New Balance 755
New Balance 767
Air Force22
New Balance 587
New Balance 498
New Balance 755
New Balance 498
Marine Corps27
New Balance 587
New Balance 767
New Balance 881
New Balance 767
*For 2 shoes, the Army classification differed from those of Runner’s World and the manufacturer.
One shoe was the New Balance 857, which the Army classification listed as a motion-control shoe but
Runner’s World and the manufacturer listed as a stability shoe; the other was the Nike Air Max Moto,
listed in the Army classification as a stability shoe but by Runner’s World and the manufacturer as a
cushioned shoe.
FIGURE 3. Device used to evaluate plantar shape: individual standing on device (A) and reflective surface showing
high-arched individual (B).
and the proportion of the plantar surface coming into contact with the acrylic
surface. Two testers independently classified each recruit’s arch height as high,
medium, or low, based on a template
(FIGURE 1). Disagreements were discussed
between raters and a final decision was
made. The between-rater reliability of
the plantar-shape evaluations (n = 66)
was formally determined using kappa
statistics and was found to be 0.91 for
both feet.27
Basic training in the Army, Air Force,
and Marine Corps was conducted for 9, 6,
and 12 weeks, respectively, during which
the assigned running shoes were worn
throughout physical training. Some re-
cruits did not complete training and were
either discharged because of unsuitability
for military service or transferred to another unit because they needed additional time to successfully complete required
training activities. For these recruits, the
amount of time they were in training in
their initial unit was obtained from administrative training records. Individuals
were followed for injuries until graduation, discharge, or assignment to another
unit.
In all 3 military services, information on injuries that occurred during
training was obtained from the Defense Medical Surveillance System. The
Defense Medical Surveillance System
regularly incorporates data on all ambulatory (outpatient) encounters that
occur within military treatment facilities and those outside military treatment facilities that are paid for by the
Department of Defense. The Defense
Medical Surveillance System provided
visit dates and ICD-9 codes for all outpatient medical visits within the recruit
training time frame for each recruit volunteer. An injury case was defined as a
recruit who had at least 1 specific ICD-9
code included in 1 of 3 injury indices:
the comprehensive injury index, overuse
injury index, and training-related injury index. These indices and the ICD-9
codes used in each have been previously
defined.23 The comprehensive injury index captures all ICD-9 codes related to
injuries, classically defined as physical
damage to the body as a result of energy
exchanges.15,16 The overuse injury index
captures the subset of musculoskeletal
injuries presumably resulting from cumulative microtrauma (overuse), such
as stress fractures, stress reactions,
tendinitis, bursitis, fasciitis, arthralgia,
neuropathy, radiculopathy, shin splints,
synovitis, sprains, strains, and musculoskeletal pain (not otherwise specified).
The training-related injury index is a
subset of the overuse injury index that
is limited to lower extremity overuse injuries and is routinely used to compare
injury rates among Army basic training
locations.
The Comprehensive Meta-Analysis
statistical package Version 2 (Biostat, Inc,
Englewood, NJ) was used to perform a
secondary analysis of the data from the
3 studies using meta-analysis. For each
injury index in each of the 3 studies, the
person-time injury incidence rate (IIR)
was calculated as the sum of recruits with
1 or more injuries divided by the sum of
total recruit time in training, multiplied
by 1000 to obtain injuries per 1000 person-days. A fixed meta-analysis model
was used that employed the IIR ratios
of the control and experimental groups
(control IIR/experimental IIR) and their
95% confidence intervals (CIs) to pro-
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Injury Incidence Rates and Meta-analyses of Experimental
and Control Groups in 3 Military Studies
TABLE 2
Men
Injury Index/
Service/Group
n
Injury
Incidence
Rate*
Rate Ratio
(CG/EG)†
Comprehensive injury
index
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Army
Women
Summary
Rate Ratio†‡
P Value§
I2
0.97 (0.88, 1.06)
.63
0%
n
Injury
Incidence
Rate*
0.99 (0.86, 1.13)
CG
1079
5.95
EG
1089
6.04
Air Force
913
6.43
EG
1042
7.04
Marine Corps
10.87
468
11.37
345
10.89
432
5.72
EG
408
5.76
Overuse injury index
373
12.96
257
6.00
.77
314
4.96
0%
0.96 (0.82, 1.13)
1079
4.37
483
8.87
EG
1089
4.55
468
9.16
345
8.50
373
10.55
257
3.29
314
2.80
0.89 (0.74, 1.08)
CG
913
5.25
EG
1042
5.86
Marine Corps
432
4.14
EG
408
4.06
Training-related injury index
.71
0%
0.91 (0.77, 1.08)
1079
3.99
483
8.80
EG
1089
4.38
468
8.59
345
6.68
373
8.41
0.85 (0.69, 1.05)
CG
913
3.94
EG
1042
4.62
Marine Corps
0.93 (0.82, 1.06)
.21
35%
0.95 (0.83, 1.09)
.21
37%
0.99 (0.83, 1.18)
CG
Air Force
57%
1.18 (0.83, 1.66)
0.90 (0.80, 1.02)
Army
.10
0.81 (0.63, 1.02)
1.02 (0.79, 1.31)
CG
0.97 (0.85, 1.08)
0.94 (0.79, 1.11)
CG
Air Force
I2
1.21 (0.94, 1.57)
0.95 (0.85, 1.06)
Army
P Value§
0.84 (0.68, 1.04)
0.99 (0.80, 1.22)
CG
Summary
Rate Ratio†‡
0.96 (0.82, 1.12)
483
0.91 (0.77, 1.09)
CG
Rate Ratio
(CG/EG)†
0.79 (0.61, 1.04)
0.98 (0.75, 1.28)
1.18 (0.79, 1.77)
CG
432
3.56
257
2.03
EG
408
3.63
314
1.72
Abbreviations: CG, control group; EG, experimental group.
*Injuries per 1000 person-days.
†
Values in parentheses are 95% confidence interval.
‡
From meta-analyses.
§
Q-statistic.
duce a summary IIR ratio and summary
95% CI that reflected the pooled results
from all 3 studies. The homogeneity of
the IIR ratios from the individual studies
was assessed using the Q-statistic and the
I2 statistic. The I2 statistic indicated the
percent of heterogeneity among studies,
with larger values indicating more het-
erogeneity and smaller values less. In
calculating I2, negative values were equal
to zero,20 indicating very little heterogeneity. Men and women were analyzed
separately in all calculations, due to large
differences in IIRs.
Because the Army study utilized a
number of different running shoes, it
was possible to examine IIRs between
different shoe makes and models using
a chi-square test for person-time.1 Each
shoe was compared to each other shoe
(2-by-2 analysis). The comprehensive
injury index was used for this analysis,
and shoes that were used by at least 40
recruits were included.
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TABLE 3
Injury Incidence Rates and Meta-analyses (Comprehensive Injury Index) of
Low- and High-Arched Individuals Wearing Different Types of Running Shoes
Men
Plantar Shape/
Service/Shoe Type
n
Injury
Incidence
Rate*
Rate Ratio†
Low
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Army
Women
Summary
Rate Ratio†‡
P Value§
I2
0.91 (0.68, 1.23)
.70
0%
n
Injury
Incidence
Rate*
0.95 (0.63, 1.43)
137
5.88
38
8.91
MCS
119
6.21
43
12.32
79
6.83
23
13.61
134
8.67
37
14.52
20
6.44
37
5.02
SS
MCS
0.79 (0.48, 1.30)
Marine Corps
27
5.44
MCS
35
4.67
High
.57
0%
0.81 (0.57, 1.16)
162
5.78
81
11.93
CS
176
7.13
81
11.76
41
9.73
64
12.48
0.99 (0.64, 1.51)
SS
119
6.93
CS
181
7.03
Marine Corps
0.90 (0.60, 1.35)
.55
0%
0.94 (0.71, 1.24)
.78
0%
1.01 (0.70, 1.48)
SS
Air Force
I2
1.28 (0.56, 2.96)
0.89 (0.69, 1.15)
Army
P Value§
0.94 (0.46, 1.90)
1.17 (0.51, 2.66)
SS
Summary
Rate Ratio†‡
0.72 (0.39, 1.34)
SS
Air Force
Rate Ratio †
0.78 (0.42, 1.43)
0.97 (0.48, 1.93)
0.92 (0.51, 1.64)
SS
34
5.46
48
5.64
CS
45
5.66
57
6.17
Abbreviations: CS, cushioned shoe; MCS, motion-control shoe; SS, stability shoe.
*Injuries per 1000 person-days.
†
Values in parentheses are 95% confidence interval. Ratio: SS/MCS (low) or SS/CS (high).
‡
From meta-analyses.
§
Q-statistic.
RESULTS
T
ABLE 2 shows the IIRs, the IIR ra-
tios, and the meta-analysis summary IIR ratios with the summary 95%
CIs. Results from the independent studies, as well as the pooled results, indicated that there was little difference between
the experimental and control groups, regardless of the injury index employed.
The Q-statistic indicated that the results
of the 3 studies were relatively homogeneous for both men and women. The I2
statistic indicated virtually no heterogeneity among studies for any injury index
among the men. Among the women, the
I2 statistic indicated somewhat more heterogeneity, but this was still relatively low
for the 2 overuse injury indices.
TABLE 3 shows a comparison of injury
rates among individuals with high and
low arches who wore different types of
running shoes. Recruits with plantar
shapes indicative of low arches who wore
stability shoes had injury rates that were
similar to those who wore motion-control shoes. Recruits with plantar shapes
indicative of high arches who wore stability shoes had injury rates similar to
those who wore cushioned shoes. The
Q-statistic and I2 statistic indicated that
the data from the 3 studies were relatively
homogeneous for both men and women.
FIGURE 4 shows the IIRs (comprehensive injury index) for shoes that were
worn by at least 40 recruits in the Army
study. There was little difference in the
injury rates based on the shoes worn for
both men (P = .14-.99) and women (P =
.44-.99).
DISCUSSION
T
he results of this analysis indicated that there was little difference
in injury rates between military
recruits who wore a running shoe assigned on the basis of plantar-shape foot
arch height compared to those who were
assigned a stability shoe regardless of
plantar shape. The 3 studies used a randomized prospective design, the same
injury definitions, and examined individuals who trained side by side in the
same units in the well-standardized basic
training environment. The results were
relatively homogeneous for the 3 studies
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[
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16
Injury Incidence Rate, Injuries per 1000 Person-Days
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14
12.16
12
11.62
10.78
10.76
10
8
6
5.94
6.49
5.83
5.90
4.66
4.58
4
n=
1390
n=
124
n=
118
n=
108
n=
69
n=
42
n=
604
Brooks
GTS7
Nike Air
Pegasus
Brooks
GTS6
n=
64
n=
42
n=
41
2
0
NB 767
Nike
Asics 2120
Structure
NB 767 Asics 2120 Nike Air
Max Moto
Brooks
GTS7
Shoe Make and Model
Men
Women
FIGURE 4. Comparison of injury incidence rates (comprehensive injury index) between different running-shoe
makes and models. Abbreviation: NB, New Balance.
in the meta-analyses. Three different injury definitions were examined, and the
results were similar in all 3 studies and
in the meta-analyses, indicating little effect on injury rates in those who were or
were not assigned shoes on the basis of
plantar shape. In addition, similar injury
rates occurred with the use of several different models of running shoes in Army
basic training.
If injury risk could be reduced by
assigning shoes on the basis of plantar shape, the largest risk reduction
might be expected between those wearing shoes specifically designed for that
plantar shape and those wearing shoes
not designed for that plantar shape.
Thus, recruits with low-arch feet who
wore motion-control shoes (presumably designed to control for excessive
pronation) were compared to those with
low-arch feet who wore stability shoes.
Likewise, recruits with high-arch feet
who wore cushioned shoes (presumably
designed to provide cushioning and allow
more foot pronation) were compared to
those with high-arch feet who wore stability shoes. Injury rates were found to
be similar, even for those comparisons
looking at match versus mismatch foot
and shoe types. Overall, the results of
the meta-analysis suggested a tendency
for recruits with low- and high-arch feet
wearing stability shoes to have slightly
lower injury rates than those wearing
shoes presumably designed specifically
for their foot type (ie, motion-control or
cushioned shoes).
A comprehensive literature search
was performed up to January 2014 to
find other studies that addressed injuries
among individuals using running shoes
that were assigned based on foot arch
height. Only 1 review33 and 1 observational study24 were found. The review33
was conducted before the studies reported here had been published and merely
noted that no investigations on this topic
existed. The observational investigation24
showed a decrease in serious injuries at
Fort Drum, NY after initiation of a running-shoe prescription program. There
]
were a number of methodological differences between the Fort Drum project and
the basic training studies reported here.
The basic training studies involved a prescription based only on plantar shape,
whereas the observational study involved
a prescription based on foot arch height
and foot flexibility. In the basic training
studies of a population of recruits, it was
ensured that the recruits were given the
correct shoe and the shoe was worn during training. The Fort Drum investigation involved soldiers who were given
the shoe prescription, but there was no
follow-up to determine whether they
had actually purchased and/or worn the
recommended shoe. In fact, a survey involving a convenience sample of 122 Fort
Drum soldiers (out of an average of 9752
estimated to be on post) found that only
11% self-reported that they had followed
the shoe-prescription advice. The basic
training studies involved a prospective
shoe prescription involving 2 randomly
assigned groups (control and experimental) training side by side in a standardized
program, with follow-up for any injury
occurring during the period of training.
The Fort Drum investigation involved a
retrospective examination of medical visits to a physical therapy clinic before and
after the shoe program was initiated. A
number of temporal factors were potential confounders in the Fort Drum project, and these were discussed at length in
the report.24 The major potential bias was
a change in the medical surveillance system used to track injuries, which was discovered after investigating the time point
when injuries dramatically decreased. In
summary, the advantages of the basic
training studies were that they (1) used
a randomized prospective design, (2)
provided considerably better knowledge
about the shoes worn, and (3) involved
a more controlled training environment.
The development of motion-control
and cushioned shoes appears to have
been based on 2 assumptions: (1) that
individuals with high and low foot arch
heights have particular gait mechanics,
and (2) that particular shoe characteris-
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tics can adjust or compensate for these
gait differences such that they more
closely conform to those of individuals
with more average arch heights. With
regard to the first assumption, individuals with low foot arches were presumed
to have disproportionate foot flexibility
that allowed the foot to pronate excessively during the stance phase of running. Individuals with high foot arch
were presumed to have rigid or inflexible feet that underpronate and impact
the ground with higher forces. However,
studies have shown that when nonsymptomatic runners and walkers with highand low-arch feet were tested using the
same shoes, there were few arch-related
differences in rearfoot motion or impact
forces.18,21,28,31 Conversely, when previously injured or symptomatic runners
with low and high arches were tested
using the same shoes, there were differences in running kinematics. Injured or
symptomatic runners with low arches
tended to demonstrate more inversion/
eversion and less internal tibial rotation
on the talus during the stance phase of
running. Injured or symptomatic runners with high arches had less inversion/
eversion, more internal tibial rotation on
the talus, more leg stiffness, higher initial
ground impact forces, and a higher rate
of initial force development on ground
impact.29,37,38 Thus, gait differences associated with foot type may be more applicable to symptomatic and previously
injured individuals than to those who are
not experiencing symptoms or who have
not been previously injured.
With regard to the second assumption, when individuals with high- or
low-arch feet ran in motion-control or
cushioned shoes, there was little difference in kinematics between these 2 foot
types, including during prolonged running.6,7 The only variable to differ was
the instantaneous loading rate (maximal instantaneous slope of initial force
development on ground impact), which
was actually higher in the cushioned shoe
(compared with the motion-control shoe)
when worn by individuals with low-arch
feet. This occurred despite the fact that,
regardless of arch type, motion-control
shoes attenuated rearfoot motion better than cushioned shoes and that cushioned shoes generally attenuated shock
better and allowed more pronation than
the motion-control shoes.6,7,11,17 Thus,
while the shoes performed as expected,
there was little difference in mechanics
between individuals with low- and higharch feet running in these shoes. The
military training studies analyzed here
additionally show that injury rates appear to be the same regardless of the type
of shoe worn by individuals with high- or
low-arch feet.
One major advantage of the basic
training studies was that all recruits were
evaluated under very similar living and
activity conditions. Recruits lived in the
same barracks, consumed meals in similar dining halls, and performed physical
training and other activities together.
Specific operational training activities
differed in the various military services
(Army, Air Force, Marine Corps), but the
physical training in which the running
shoes were used was similar and generally consisted of calisthenics, various
movement drills, and running in groups
of those with similar fitness levels. The
findings were similar in all 3 services,
showing no difference between the experimental and the control groups in terms
of injury outcomes.
Although we did not consider covariates in the present summary, several were
considered in the individually reported
investigations.22,26,27 These covariates
included age, physical characteristics,
physical fitness, and lifestyle characteristics (cigarette smoking, prior physical activity level, prior injuries, and menstrual
history). Many of these characteristics
had been shown to be associated with
injuries in past investigations.25 To see if
these factors might have made a difference in injury rates, a fixed-model metaanalysis was performed on the adjusted
hazard ratios from the Cox regressions
reported in the articles. The pooled adjusted hazard ratios from the 3 studies
were 1.04 (95% CI: 0.94, 1.16; Q-statistic,
P = .54) for men and 1.07 (95% CI: 0.95,
1.20; Q-statistic, P = .64) for women. This
analysis supports the earlier ones reported here, showing no difference in injury
rates among the control and experimental groups when the significant covariates
were considered.
CONCLUSION
T
he results of the present investigation indicated that selecting or
assigning running shoes on the basis
of foot arch type did not reduce injuries
in military basic training compared to assigning a stability shoe regardless of plantar shape. In addition, injury rates for
several brands of running shoes were similar during Army basic training. It should
be noted that these studies examined
the effect of selecting or assigning running shoes only on the basis of the static
weight-bearing plantar shape. This was
the practice in basic training when the
studies were conducted and the method
recommended by popular running magazines and shoe companies to presumably
reduce the risk of injury. Anecdotal observations during the studies indicated
that there was a great amount of variety
of recruit foot sizes and shapes. A single
running shoe is not likely to accommodate the variety of foot types encountered
in basic training. Consideration should be
given to providing recruits with a selection of running shoes that at least provide a wide range of lengths and widths,
although shoe selection based on plantar
shape is not necessary. t
KEY POINTS
FINDINGS: Assigning running shoes on the
basis of the height of the longitudinal
foot arch did not influence injury rates
in military basic combat training. Injury
rates in military basic training were also
similar regardless of the type of running
shoe worn.
IMPLICATIONS: Selecting the type of running shoes based on foot arch height
does not appear to be beneficial in
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reducing injury risk in military basic
training.
CAUTION: These studies only examined
shoe assignments and injuries in US
military basic training, and shoe selection or assignment was based exclusively
on the shape of the footprint.
ACKNOWLEDGEMENTS: We would like to thank
Journal of Orthopaedic & Sports Physical Therapy®
Downloaded from www.jospt.org at on November 2, 2014. For personal use only. No other uses without permission.
Copyright © 2014 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.
Claudia Coleman and Ryan Steelman for assistance with obtaining references, and Ryan
Steelman for editorial review.
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