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Journal of Science and Medicine in Sport 12 (2009) 679–684
Original paper
Effect of foot orthoses on magnitude and timing of rearfoot and tibial
motions, ground reaction force and knee moment during running
Mansour Eslami a,b,c,∗, Mickaël Begond, Sébastien Hinse b,c, Heydar Sadeghie,
Peter Popov b,c, Paul Allardb,c
aDepartment of Physical Education and Sport Sciences, University of Mazandaran, Iran
bDepartment of Kinesiology, University of Montreal, Canada
cLaboratoire d’Étude du Mouvement, Research Center, Sainte-Justine Hospital, Canada
dSchool of Sport and Exercise Sciences, University Loughborough Leics, United Kingdom
eDepartment of Physical Education and Sport Sciences, Tarbiat Moallem University, Iran
Received 11 April 2007; received in revised form 28 March 2008; accepted 15 May 2008
Abstract
Changes in magnitude and timing of rearfoot eversion and tibial internal rotation by foot orthoses and their contributions to vertical ground
reaction force and knee joint moments are not well understood. The objectives of this study were to test if orthoses modify the magnitude
and time to peak rearfoot eversion, tibial internal rotation, active ground reaction force and knee adduction moment and determine if rearfoot
eversion, tibial internal rotation magnitudes are correlated to peak active ground reaction force and knee adduction moment during the first
60% stance phase of running. Eleven healthy men ran at 170 steps per minute in shod and with foot orthoses conditions. Video and force-plate
data were collected simultaneously to calculate foot joint angular displacement, ground reaction forces and knee adduction moments. Results
showed that wearing semi-rigid foot orthoses significantly reduced rearfoot eversion 40% (4.1◦;p=0.001) and peak active ground reaction
force 6% (0.96 N/kg; p= 0.008). No significant time differences occurred among the peak rearfoot eversion, tibial internal rotation and peak
active ground reaction force in both conditions. A positive and significant correlation was observed between peak knee adduction moment and
the magnitude of rearfoot eversion during shod (r= 0.59; p= 0.04) and shod/orthoses running (r= 0.65; p= 0.02). In conclusion, foot orthoses
could reduce rearfoot eversion so that this can be associated with a reduction of knee adduction moment during the first 60% stance phase of
running. Finding implies that modifying rearfoot and tibial motions during running could not be related to a reduction of the ground reaction
force.
© 2008 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Keywords: Orthotic device; Foot and tibial movement; Ground reaction force; Knee moment; Running injuries
1. Introduction
Excessive rearfoot eversion (REV) and tibial internal rota-
tion (TIR) during repetitive motions such as running have
been associated with Achilles tendinopathy, medial tibial
stress syndrome, patellofemoral pain syndrome and knee
injuries.1,2 Foot orthoses are prescribed to align the rearfoot
and tibia as well as limiting rearfoot eversion and tibial inter-
nal rotation during locomotion. Previous studies reported that
∗Corresponding author at: Department of Physical Education and Sport
Sciences, University of Mazandaran, Iran.
E-mail address: mseslami@yahoo.com (M. Eslami).
foot orthoses reduced either REV3or TIR.2,4 Because the tim-
ing and magnitude of REV and TIR attenuate ground reaction
force and dissipate stress, their reduction may not be the only
function of foot orthoses.5–7 Limiting foot and tibial rotations
by means of foot orthoses could also reduce muscle force and
modify lever arms.8These changes in the components of joint
moment could affect load distribution at the knees. Generally,
the effect of changes in timing and magnitude of REV and
TIR with the use of foot orthoses on ground reaction forces
and muscle moments is not well understood during running.
Timing of peak REV, TIR and knee flexion must be syn-
chronised during early stance phase of gait for cushioning
external force and absorbing shock.7If REV and TIR peak
1440-2440/$ – see front matter © 2008 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.jsams.2008.05.001
680 M. Eslami et al. / Journal of Science and Medicine in Sport 12 (2009) 679–684
continue beyond mid-stance during knee extension, this spec-
ulated to an antagonist motion and knee injury.7Subotnick9
reported that peak REV and TIR must occur before mid-
stance to attenuate the peak vertical reaction force and the
foot must supinate to become rigid at push-off. Little evidence
exists on the timing among the peak REV, TIR and vertical
ground reaction force during the stance phase of running. To
our knowledge, no research has addressed the contributions
of these timing events to peak vertical ground reaction forces.
Vertical ground reaction forces have been proposed as
indications of loading conditions.10,11 They could increase
when normal foot and tibial motions are restricted or
exaggerated.11 Perry and Lafortune11 reported that the active
vertical ground reaction force (AVGRF) increased with the
use of medially posted orthoses when the peak REV angle was
reduced by 6.7◦during running. In contrast, no significant
changes in peak AVGRF was observed when REV decreased
by 3◦12 or when the rearfoot was everted excessively.11 These
findings suggest that the magnitude of lower-limb motion
could contribute to the vertical ground reaction force during
running. Though foot orthoses control rearfoot eversion and
tibial rotation (without regard to knee flexion), their contri-
bution at reducing the peak vertical ground reaction force is
still unclear.
Knee adduction moment (KAM) is thought to increase
load in the medial aspect of the tibial plateau and femoral
condyle, thereby causing knee pain in runners.13 To our
knowledge no investigation was carried out to determine if
changes in the REV and TIR magnitudes caused by foot
orthoses could be associated to peak KAM during running.
Because REV and TIR as well as peak AVGRF and KAM
occur during the first 60% stance phase of running, we
hypothesized that foot orthoses perturb their relationships
during this period of stance phase. This study aimed to test if
foot orthoses modify the magnitude and time to peak of REV,
TIR, peak AVGRF and KAM and determine if REV and TIR
magnitudes are correlated to peak AVGRF and KAM during
the first 60% stance phase of running.
2. Method
Eleven able-bodied men having an average age of 27.9
(S.D. 4.5) years, weight of 86.1 (S.D. 7.0) kg and height of
179.0 (S.D. 5.9) cm volunteered for this research. The num-
ber of participants was based on a αof 0.05 and a βof 0.20
according to Erdfelder et al.14 None of the participants had
any orthopedic or neurological ailments affecting their run-
ning gait. The experimentation procedures were approved
by the Hospital Ethics Committee and were explained to all
participants.
Six cameras (Motion Analysis Corporation, Santa Rosa,
USA) were arranged in two arcs of 120◦positioned on the
left and right sides of a force-plate (AMTI, Model OR6-5,
960 Hz) located in the middle of a 10-m runway. The capture
volume (0.5 m in length×0.5 m in width×0.75m in height)
Fig. 1. Anterior and lateral views of marker placement in the barefoot and
shod conditions.
covered the right lower-limb motions during the running tri-
als. Nine reflective skin markers, 16mm in diameter, were
attached to the right foot and tibia as shown in Fig. 1. Three
of them were fixed over the posterior calcaneus, medial and
lateral sides of the calcaneus to define a rearfoot coordinate
system according to the ISB recommendations.15 An addi-
tional marker was located on the extremity of the second
toe to calculate the ankle moment. Five other markers were
placed over the tibial tubercle, head of fibula, anterior middle
aspect of the tibia, medial malleolus and lateral malleolus to
define the tibial coordinate system. During the running trials,
three markers namely, the extremity of the second toe, medial
malleolus and tibial tubercle were removed and calculated as
virtual markers. This was done to avoid marker dropout, skin
movement artifacts and hidden markers which may occur for
landmarks on the medial side of the foot and tibia during
running trials.
Participants were tested in two running conditions. The
shod condition consisted of sandals where three straps cov-
ered the posterior side of the calcaneus, the tarso-metatarsal
joints and the metatarso-phalangeal joints. Sandals allowed
an easy tracking of the markers during running trials and were
previously used to evaluate the effects of foot orthoses on the
rearfoot and tibial motions.4,16 In the shod/orthoses condi-
tion, participants were fitted with semi-rigid foot orthoses.
The orthoses were customised by using foambox in a non-
weight bearing condition. They were fabricated from a ductile
polypropylene plastic material (3 mm in thickness). A groove
in the heel cap was designed to create two medial and lateral
flanges. Then a laterally curved notch in the medial flange was
located until heel centre to prevent rearfoot eversion during
running. The orthoses were fixed in the sandals by means of
a double-sided adhesive tape.
Ten running trials were performed in the shod and
shod/orthoses conditions in a block random order. In each
experimental condition, participants ran at a cadence of
170 steps per minute controlled by means of a metronome.
The video cameras (60 Hz) were synchronised with the
M. Eslami et al. / Journal of Science and Medicine in Sport 12 (2009) 679–684 681
force-plate measurements (960 Hz). All kinematic data were
filtered at 8 Hz with a low-pass zero phase shift fourth-order
Butterworth filter. Three-dimensional joint rotations were
calculated according to Grood and Suntay.17 The sequences
of rotations were plantar/dorsiflexion about the medio-lateral
axis of the proximal segment, abduction/adduction about
the floating axis and inversion/eversion about the ante-
rior/posterior axis of the distal segment. TIR was measured
as a transverse plane motion of the foot with respect to
the tibia. The segment inertial parameters were obtained
from the adjustments to Zatsiorsky-Seluyanov’s parameters
as outlined by De Leva.18 A Newton–Euler inverse dynamics
approach was applied to calculate knee moments. The knee
moments were normalised with respect to the participant’s
body mass.
There were four dependent variables. Rearfoot eversion
and tibial internal rotation magnitudes were calculated by
determining the difference between their respective values
at heel-strike minus their maximum value occurring dur-
ing the first 60% of the stance phase. Peak AVGRF and
peak KAM were determined during that period of stance
phase. Furthermore, time to peak for each variable was iden-
tified and reported as a percentage of the stance phase.
The average of the magnitude and normalised time to peak
values was taken over the ten running trials for each depen-
dent variable and for the shod and shod/orthoses conditions.
Kolmogorov–Smirnov tests performed on the averages of the
dependent variables showed no significant differences with a
normal distribution (0.46 < Z< 0.95; 0.32 < p< 0.99).
Paired t-tests were performed to compare the mean
magnitude of the four dependent variables between shod
and shod/orthoses conditions. Two-way repeated measures
ANOVA (four variables ×two conditions) tested the differ-
ence on normalised time to peak data for all four dependent
variables between the shod and shod/orthoses conditions.
Protected t-tests were used if a main effect was found to be
significant. Pearson’s correlations were performed to deter-
mine if the magnitude of REV was correlated with the peak
AVGRF and KAM and verify if the magnitude of TIR was
correlated to the peak AVGRF and KAM in the shod and
shod/orthoses conditions. The level of significance was set at
p< 0.05 for all tests.
3. Results
Fig. 2 shows the mean magnitudes of the four dependent
variables for the shod and shod/orthoses conditions during
running. With semi-rigid orthoses, REV magnitude and peak
AVGRF decreased, respectively by an average of 40% (4.1◦;
p= 0.001) and 6% (0.96 N/kg; p= 0.008), when compared
with the shod condition. No statistical difference was found in
the mean TIR magnitude (p= 0.06) and peak KAM (p= 0.19).
For the normalised time to peak values, a significant main
effect of variables was observed (F3,30 = 5.6; p= 0.003). The
protected tpost hoc tests revealed that significant timing dif-
Fig. 2. Mean magnitude of (a) rearfoot eversion, (b) tibial internal rotation,
(c) peak knee adduction moment, and (d) peak ground reaction force. (*)
Indicates statistical differences between shod and shod/orthoses conditions
for p< 0.05.
ferences were observed between peak KAM (30.4%) and
peak TIR (45.6%) (p= 0.02) as well as peak KAM and peak
AVGRF (39.7%) (p= 0.03). No significant difference was
observed between time to peak REV (38.4%) and time to
peak for the other variables (0.06 < p< 0.35). Neither main
effect was noted for the conditions (F1,10 = 1.04; p= 0.33),
nor for the interaction effect of variables and conditions
(F3,30 = 1.35; p= 0.27). These findings imply similar time
sequences for the four variables in the shod and shod/orthoses
conditions.
Table 1 presents Pearson’s product moment correlation
coefficients between variables in the shod and shod/orthoses
conditions. The average coefficient of correlation rwas rela-
tively low at 0.34. Statistically significant correlations were
observed between the REV magnitude and peak KAM in both
shod (r= 0.59) and shod/orthoses (r= 0.65) conditions.
4. Discussion
The results of the present study suggest that wearing a
semi-rigid foot orthosis significantly reduces REV magni-
682 M. Eslami et al. / Journal of Science and Medicine in Sport 12 (2009) 679–684
tude and active ground reaction force with no significant
decrease in TIR magnitude and peak KAM. Results revealed
that there was a trend for a reduction in TIR (p= 0.06) by
reducing REV during running. These findings are in accor-
dance with MacLean et al.,3but in contrast to Nawoczenski et
al.,4Nester et al.6and Stacoff et al.2Variability in the move-
ment pattern in the lower-limb segments in individuals could
be the factor in response to foot orthoses. Bellchamber and
van den Bogert and coworker19 found high inter-individual
differences in lower-limb segments movement pattern. They
found that during running, movement transfer was mainly
from tibia to rearfoot, nonetheless, some participant showed
an inverse movement pattern. This movement transfer was
suggested depending on the flexion position of the foot (plan-
tar/dorsiflexion), loading of the ankle joint complex, fusion of
selected joints and integrity of the ligaments.20 The observed
disparity in the results of this study compared with previous
studies for these variables could be attributed to individual
differences in response to orthoses as well as the type of foot
orthoses utilised.
With the use of orthoses, a reduction of 10–20% in peak
AVGRF was reported in the literature. This amount of reduc-
tion was considered insufficient to prevent injuries.8In this
study, the AVGRF was decreased by an average of 5.5%.
This small reduction could be related to the flexibility of the
semi-rigid orthoses. Peak AVGRF was proposed as a signif-
icant discriminator between groups of injured and uninjured
runners with stress fractures.21 It is speculated that ground
reaction forces occurring during physical activities such as
normal running might not be a major factor in the develop-
ment of injuries in running. It is unknown to which extent
the peak AVGRF could be related to the risk of lower-limb
injuries during running.
The absence of a significant effect of the semi-rigid
orthoses on KAM is supported by Maly et al.22 though these
results are different from those presented by Kakihana et al.,23
Mündermann et al.12 and Nester et al.6Individual differences
in response to orthoses, type of foot orthoses utilised and
difference in motion patterns could be discrepancy of these
findings. A large KAM could increase the risk of overloading
the medial structures of the knee contributing to the iliotibial
band friction24 and patellofemoral pain syndromes25 in run-
ners. Wedged foot orthoses were used as a treatment in order
to change load distributions at the knee. Yasuda and Sasaki26
Table 1
Correlation coefficients (r) and p-values between rearfoot eversion (REV)
and peak active ground reaction forces (AVGRF) and knee adduction
moment (KAM) and between tibial internal rotation (TIR) and AVGRF and
KAM in shod and shod/orthoses conditions during running
Shod Shod/orthoses
rprp
REV–AVGRF 0.17 0.61 0.32 0.32
REV–KAM 0.59 0.04 0.65 0.02
TIR–AVGRF 0.48 0.12 0.36 0.27
TIR–KAM 0.13 0.69 0.03 0.90
found that a laterally wedged insole reduced the load in the
medial compartments of the knee in standing. Keating et al.27
reported that a laterally wedged insole might be effective to
reduce knee pain in osteoarthritis patients during the stance
phase of walking. In our study, a semi-rigid orthosis did not
change the peak KAM during running.
This study was the first to report the outcome of the use
of foot orthoses on time to peak of REV, TIR, AVGRF and
KAM during the stance phase of running. Results suggest
that the peak value for the KAM occurred earlier than peak
AVGRF and TIR during the early stance in both conditions.
Findings show that the use of orthoses could not change the
observed timing differences. Hunt et al.13 reported a similar
finding although they tested only the frontal plane component
of the ground reaction force. The lack of significant timing
differences among peak REV, TIR and AVGRF in normal
individuals indicates that the timing of these events does not
differ during the first 60% stance phase of running. Abnor-
malities in foot structure or the malalignment of foot and leg
may result in a disruption of these timing events which could
be synchronised by wedged foot orthoses. This issue will be
addressed in a future study.
In this study, the peak AVGRF was not correlated with the
magnitude of REV and TIR in shod and shod/orthoses con-
ditions during running. Mündermann et al.12 also reported
no significant change in the peak active ground force while
REV was decreased. In contrast, Perry and Lafortune11 noted
that AVGRF was increased when REV was reduced by 6.7◦.
We suggest that, small and non-consistent reductions in the
magnitudes of rearfoot eversion (without regard to knee flex-
ion) by means of foot orthoses could not be associated with
the observed reduction in peak AVGRF. It is speculated that
timing and magnitude of the ankle and knee movements in
the sagittal plane as well as shock absorbing characteristics
of orthoses could be more effective in cushioning the peak
AVGRF than foot pronation itself.
A significant positive correlation between REV magni-
tude and peak KAM was observed in shod and shod/orthoses
conditions during running in healthy participants. Keating et
al.27 reported that during walking, a laterally wedged insole
increased the eversion angle of the subtalar joint, therefore,
reducing adduction moment at the knee. Kakihana et al.28
observed that wearing a laterally wedge decreased KAM as a
result of more laterally shifted location of the COP. This can
be attributed to a reduced knee moment arm length.23 Nigg
et al.29 did not find significant change in the average shift of
COP by the use of a medially wedge during running. They
also reported no correlation between the COP location and
knee moment during running. On the other hand, Nawoczen-
ski and Ludewig30 indicted that a reduction of EMG activity
for the biceps femoris with the use of orthoses during run-
ning. These recent findings imply a likelihood of interaction
between the rearfoot kinematic and muscle activity during
running. To reduce peak KAM, muscle activity could be more
affected than lever arm when the foot orthoses control rear-
foot eversion during running. This could be possible with a
M. Eslami et al. / Journal of Science and Medicine in Sport 12 (2009) 679–684 683
greater reduction of REV magnitude. Finding suggests that
patients with excessive rearfoot eversion could have a sig-
nificant response to the treatment of excessive loading in the
medial compartment of the knee during running with medial
wedged foot orthoses.
This work has some limitations and thus, caution must be
exercised in the interpretation of the findings of this research.
First of all, the model representing the foot, utilised only two
segments moving about the ankle. Another limitation is the
difficulty to extrapolate meaningful results from a 170-step
per minute speed running trial. It must be pointed out that,
higher running speeds or sideward cutting movements could
change the joint motion patterns. Because changes in run-
ning speed could have confounding effects on the segments’
coupling motion, this was controlled at 170-step per minute
speed running trial by a metronome across all trials. Thus,
the interpretation of observed joint motion patterns is limited
to that running speed.
In conclusion, foot orthoses could reduce rearfoot ever-
sion so that this can be associated with a reduction of knee
adduction moment during the first 60% stance phase of run-
ning. Timing to peak of rearfoot eversion, tibial internal
rotation, peak active ground reaction force and knee adduc-
tion moment could not change by the use of foot orthoses.
Finding implies that modifying rearfoot frontal plane motion
during running could not be related to a reduction of the
ground reaction force.
5. Practical implications
•Clinicians should be aware that controlling the frontal
plane motion of foot by the use of orthoses could be asso-
ciated with a reduction of excessive asymmetrical loading
at the knee.
•Coaches and trainers should consider that the shock
absorbing characteristic of orthoses could be more effec-
tive in reducing the peak active vertical ground reaction
force in activities, such as landing, which have high loading
conditions.
Acknowledgments
Partial funding for this project was obtained from the Min-
istry of Sciences, Research, and Technology of Iran and the
Natural Science and Engineering Council of Canada.
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