Journal of
Functional Morphology
and Kinesiology
Article
Changes in Plantar Pressure While Running with a
Jogging Stroller
Christoph Mickel 1, *, Antonia Baltrusch 1 , Fabian Holzgreve 1 , Laura Maltry 1 ,
Hagen Hartmann 1 , Michael Keiner 2 and Klaus Wirth 3
1
2
3
*
Department of Human Movement Science and Athletic Training, Institute of Sports Sciences,
Goethe University, 60487 Frankfurt am Main, Germany; [email protected] (A.B.);
[email protected] (F.H.); [email protected] (L.M.); [email protected] (H.H.)
Swimming Federation of the State Lower Saxony, 30169 Hannover, Germany;
[email protected]
Department of Sport and Exercise Sciences, University of Applied Sciences Wiener Neustadt,
2700 Wiener Neustadt, Austria; [email protected]
Correspondence: [email protected]; Tel.: +49-69-798-24533
Academic Editor: Giuseppe Musumeci
Received: 3 May 2016; Accepted: 27 July 2016; Published: 10 August 2016
Abstract: Despite the common use of jogging strollers, only a few studies cover their influence
on running patterns. Kinematic studies have shown differences in the upper body movement,
while potential changes in plantar pressure remain unclear. Therefore, 30 healthy sport students
were asked to run at a self-selected speed with and without a jogging stroller on a treadmill.
Via bilateral insole pressure measurements, the plantar pressure distribution and the stride length
were quantified. A significantly decreased pressure for running with a jogging stroller was found in
the forefoot, metatarsus, inner edge, outer edge and for the total pressure of the left foot. The right foot
showed similar significances for all foot areas except the metatarsus. Stride length was significantly
shorter when running with a jogging stroller. As stride length and plantar pressure are known
to correlate, the reduced stride length in running with a jogging stroller can partially explain the
measured decrease in plantar pressure. Further, the partial weight-bearing, which is needed to
keep the jogging stroller in line, can also contribute to the decrease in plantar pressure. Moreover,
the unilateral weight-bearing enlarges the base of support and could also be a reason for the decrease
in plantar pressure. In conclusion, our results show statistically significant changes in plantar
pressure, but these are not of clinical importance as the effect sizes are very low. Therefore, no specific
training recommendations for running with a stroller have to be made.
Keywords: plantar pressure; jogging stroller; running
1. Introduction
Running is a modern sport. It requires little equipment and can easily be integrated into everyday
life. Therefore unsurprisingly, parents have also discovered running as a leisure sport which has led
to the development of jogging strollers to enable a combination of child care and running. Although
such strollers are a common sight in parks and city centers, differences in biomechanics while running
with one may be expected, but only very few studies on the topic exist [1–5]. Most available studies
have examined physiological parameters (e.g., heart rate or oxygen uptake), explaining the rise in
self-reported exertion [1–4]. Information on kinematic changes is sparse and partly contradictive.
It has been described that the use of a stroller induces adaptations in stride length and cadence,
while others did not find any changes. Brown [1] reported shortened stride lengths and therefore an
increase in cadence (running speed was not significantly altered, but the number of steps (measured
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J. Funct. Morphol. Kinesiol. 2016, 1, 314–321
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via pedometer) and step length (measurement is not described in the publication) were), but neither
Smith [2] nor O’Sullivan and Kieran [5] could confirm these results. The latter recently published
complementary kinematic data. Via 3D movement analysis, a decline in trunk rotation in the sagittal
plane, which had to be expected as at least one arm is fixed while running with a stroller, has been
shown [5]. Moreover, they have reported an increase in the forward lean of the trunk, in pelvic tilt
and in hip flexion at initial contact as well as a limited hip extension. Nevertheless, they did not find
significant changes in knee or ankle joint movements. The authors postulated that this is due to a
forward shift of the center of pressure (COP), which is needed to set the stroller in motion [5].
Because of the limited number of studies on running with a stroller, we have also looked for
similar tasks. Even though the movement speed is slower, walking with a walker seems to be
the best approximation. Obviously, the elderly tend to use their walker for partial weight-bearing
while runners can be expected to almost exclusively push the stroller. Nevertheless, there are still
some similarities: The movement of the upper limb(s) is limited, which reduces trunk rotation,
and the device has to be moved forward. Studies analyzing walker-assisted walking have reported
altered movement patterns. Alkjaer [6] found partly unloaded ankle and knee joints due to reduced
knee extension and plantar flexion. These findings agree with a significant reduction in lower-limb
muscle activity [7]. This effect was stronger if weight-bearing was increased. As the trunk sway
remained unchanged, it was concluded that stability was gained through forces of the upper limbs [7].
This matches Ishikura’s findings [8], which show the weight-bearing force being determined by the
flexion angle of the hip joint. Given that O’ Sullivan and Kieran [5] also showed an increase in hip
flexion for running with a stroller, the similarities in movement patterns become obvious.
In total, our literature search revealed that, despite the existing studies on physiological and
kinematic changes, kinetic data on running with a stroller has not yet been reported to our knowledge.
O’ Sullivan and Kiernan [5] only refer to movement analysis data when concluding that the decline in
rotation and the additional weight of the stroller is completely compensated for by the trunk and the
pelvis. Whether this further influences the loading of the joints in the lower extremities is still an open
question. As studies on walker-assisted walking have indicated a reduction in plantar pressure, valid
data for running with a stroller is missing. Since our study is the first of its kind, we have decided
to account for its explorative nature by choosing an open hypothesis: The plantar pressure shows
significant differences between running with a stroller and normal running at the same, self-selected
running speed.
2. Materials and Methods
2.1. Participants
Fifteen male and 15 female healthy physical education students (experienced recreational runners)
(age (in years) 24.9 ˘ 2.40; height (in cm) 174 ˘ 8; weight (in kg) 68.16 ˘ 9.85) volunteered to participate
in the study. All participants gave informed written consent and the study was approved by the
institutional review board. Further, volunteers were only allowed to participate if they had not had
any injury of the lower extremities in the last six months. Prior to data collection, all participants
completed a self-made anamnesis questionnaire which amongst others assessed running experience in
general, on a treadmill, and with a stroller. All of them reported to be recreational runners, but none
of them had experience in running on a treadmill, which is why we included a habituation period,
and with a stroller. Furthermore, they were asked if orthopedic aids (e.g., specific, orthopedic insoles)
have usually been used while running (=one participant).
2.2. Bilateral Insole Pressure Measurement
In order to measure changes in pressure distribution on the plantar surface while running with the
jogging stroller we used a bilateral insole measurement system (T&T Medilogic, Schönefeld, Germany).
The company amounts the measurement error with ˘1%. Insoles were provided in different shoe
J. Funct. Morphol. Kinesiol. 2016, 1, 314–321
316
J. Funct. Morphol. Kinesiol. 2016, 1, 314-321
316
sizes. In order to maintain running comfort, these were positioned above (individual sports specific)
sports
in use.
Each insole
includessensors
64 pressure
sensors
which
the
system
insolesspecific)
if in use.insoles
Each if
insole
includes
64 pressure
which
empower
theempower
system to
calculate
to
calculate
mean
pressure
results
for
five
foot
areas
and
the
whole
foot
(forefoot,
metatarsus,
heel,
mean pressure results for five foot areas and the whole foot (forefoot, metatarsus, heel, inner edge,
inner
edge,and
outer
edge
and
total;1).
seeFurthermore,
Figure 1). Furthermore,
the double
stride
was
outer edge
total;
see
Figure
the double stride
length
was length
obtained
inobtained
order to
in
order to
calculate
changes while
in cadence
while
running
with and
jogging stroller.
calculate
changes
in cadence
running
with
and without
thewithout
jogging the
stroller.
Figure
pressure-sensitive insoles.
insoles.
Figure 1.
1. Schematic
Schematic presentation
presentation of
of the
the five
five foot
foot areas
areas of
of the
the used
used pressure-sensitive
2.3.
2.3. Procedures
Procedures
After
inin
thethe
running
shoes
of
After the
the pressure-sensitive
pressure-sensitiveinsoles
insoleshad
hadbeen
beenpositioned
positionedand
andcalibrated
calibrated
running
shoes
the
participant,
sheshe
or he
asked
to warm
up running
on the
(Woodway,
ProXL,
Weil
of the
participant,
or was
he was
asked
to warm
up running
ontreadmill
the treadmill
(Woodway,
ProXL,
am
Rhein,
Germany)
for
7.5
min
without
and
another
7.5
min
with
the
jogging
stroller
(Naturkind,
Weil am Rhein, Germany) for 7.5 min without and another 7.5 min with the jogging stroller
Varius Pro, Varius
Engerwitzdorf,
Austria). Austria).
Meanwhile,
self-selected
runningrunning
of the ofparticipant
was
(Naturkind,
Pro, Engerwitzdorf,
Meanwhile,
self-selected
the participant
determined
by asking
them to
“select
a running
speed for
a comfortable
30 min run”.
Average
was
determined
by asking
them
to “select
a running
speed
for a comfortable
30 min
run”.
running
speed
was
determined
to
be
8
±
1.37
km/h.
Following
this
familiarization
period
and
pause
Average running speed was determined to be 8 ˘ 1.37 km/h. Following this familiarizationaperiod
of
approximately
1 min, the first1condition
Again,
by a pause
of approximately
and
a pause of approximately
min, the was
first tested.
condition
wasfollowed
tested. Again,
followed
by a pause
1ofmin,
the
second
condition
was
tested.
The
order
of
conditions
was
randomized
(—participant
A’s
approximately 1 min, the second condition was tested. The order of conditions was randomized
first
condition
was
without
the
stroller,
followed
by
the
second
condition
with
the
stroller;
for
(—participant A’s first condition was without the stroller, followed by the second condition with
participant
B
the
conditions
order
was
reversed
and
so
forth).
In
each
condition,
participants
ran
for
the stroller; for participant B the conditions order was reversed and so forth). In each condition,
five consecutive
minutes
at their self-selected
running
speed. Plantar
pressure
was Plantar
measured
for 30
participants
ran for
five consecutive
minutes at
their self-selected
running
speed.
pressure
swas
starting
after
3
to
3.5
min.
In
the
“with
stroller”
condition,
participants
were
further
asked
to
measured for 30 s starting after 3 to 3.5 min. In the “with stroller” condition, participants push
were
the
stroller
with
their
right
hand
continuously.
To
account
for
an
infant’s
weight
a
10
kg
barbell
disc
further asked to push the stroller with their right hand continuously. To account for an infant’s weight
was
put
in
the
jogging
stroller.
After
each
data
acquisition,
participants
were
asked
to
rate
their
level
a 10 kg barbell disc was put in the jogging stroller. After each data acquisition, participants were
of
effort
6–20 level
Borg of
scale
to get
toatheir
perceived
fatigueability
Figure
asked
to via
ratea their
effort
viaaasuperficial
6–20 Borg overview
scale to get
superficial
overview
to their [9].
perceived
2fatigueability
shows the experimental
one participant
pushing
[9]. Figure 2 set-up
shows with
the experimental
set-up
with the
onestroller.
participant pushing the stroller.
Statistical analysis was performed using SPSS 15.0 (SPSS Inc., Chicago, IL, USA) and Excel (2010;
Microsoft, Santa Clara Valley, CA, USA). Data was tested for normal distribution via the
Kolmogorov-Smirnov test. As this test revealed significant results, the non-parametric equivalent of
J. Funct. Morphol. Kinesiol. 2016, 1, 314–321
J. Funct. Morphol. Kinesiol. 2016, 1, 314-321
317
317
the paired
t-test,
the Wilcoxon
test, wasusing
used SPSS
to test
significant
differences
in and
the parameters
Statistical
analysis
was performed
15.0for
(SPSS
Inc., Chicago,
IL, USA)
Excel (2010;
between theSanta
two conditions.
Furthermore,
the Spearman
was for
performed
test if the changes
in
Microsoft,
Clara Valley,
CA, USA).
Data was test
tested
normaltodistribution
via the
J.
Funct.
Morphol.
Kinesiol.
2016,
1,
314-321
317
plantar
pressure
correlate
with
stride
length.
For
all
statistical
procedures,
the
level
of
significance
Kolmogorov-Smirnov test. As this test revealed significant results, the non-parametric equivalent
was
a priori
to p the
< 0.05.
of
thesetpaired
t-test,
Wilcoxon test, was used to test for significant differences in the parameters
the paired t-test, the Wilcoxon test, was used to test for significant differences in the parameters
between the two conditions. Furthermore, the Spearman test was performed to test if the changes in
between the two conditions. Furthermore, the Spearman test was performed to test if the changes in
plantar
pressure
correlate
withwith
stride
length.
ForFor
allall
statistical
plantar
pressure
correlate
stride
length.
statisticalprocedures,
procedures,the
thelevel
level of
of significance
significance was
set a was
priori
to
p
<
0.05.
set a priori to p < 0.05.
Figure 2. Photo of one subject running on the treadmill pushing the stroller.
Figure 2. Photo of one subject running on the treadmill pushing the stroller.
Figure 2. Photo of one subject running on the treadmill pushing the stroller.
3. Results
3. Results
The distribution of plantar pressure of the right and left foot compared between the two
3. Results
The
distribution
of plantar
pressure
the right
and leftinfoot
compared
the two Next
conditions
without
the stroller
and with
the of
stroller
are shown
Figures
3 andbetween
4, respectively.
The
distribution
of
plantar
pressure
of
the
right
and
left
foot
compared
between
the
two
conditions
without
the
stroller
and
with
the
stroller
are
shown
in
Figures
3
and
4,
respectively.
Next
to the total pressure of the whole foot, data included a differentiation between theconditions
forefoot,
to
the
total
pressure
of
the
whole
foot,
data
included
a
differentiation
between
the
forefoot,
without
the
stroller
and
with
the
stroller
are
shown
in
Figures
3
and
4,
respectively.
Next
to
total
metatarsus, heel, inner and outer edge. Statistical analysis revealed significant differences inthe
plantar
metatarsus,
heel, inner
and
outer
edge. aStatistical
analysisbetween
revealed the
significant
differences
in plantar
pressure
of
the
whole
foot,
data
included
differentiation
forefoot,
metatarsus,
heel,
inner
pressure between the “no stroller” (=NS) and “with stroller” (=WS) conditions in the right and left
pressure between the “no stroller” (=NS) and “with stroller” (=WS) conditions in the right and left
and
foot.outer edge. Statistical analysis revealed significant differences in plantar pressure between the “no
foot.(=NS) and “with stroller” (=WS) conditions in the right and left foot.
stroller”
Pressure
Left
Pressure Distribution
Distribution Left
1.20 1.20
* *
**
0.80 0.80
Pressure [N/cm²*s]
Pressure [N/cm²*s]
1.00 1.00
0.60
0.40
*
0.60
0.40
*
*
*
*
0.87 0.82
0.87 0.82
0.20
0.64 0.62
0.40 0.39
0.20
0.40 0.39
0.00
0.00
*
forefeet
forefeet
metatarsus
metatarsus
0.36 0.35
0.64 0.62
0.36 0.35
heel
heel
inner edge
inner edge
0.53 0.50
0.59 0.56
outer edge
total
0.53 0.50
outer edge
0.59 0.56
total
Figure
3. Pressure distribution of the left foot. * indicates statistically significant differences. Black
Figure 3. Pressure distribution of the left foot. * indicates statistically significant differences. Black
boxesboxes
for the
stroller
(=NS)
forwith
withstroller
stroller
(=WS)
conditions.
for without
the without
stroller
(=NS)and
andwhite
white boxes
boxes for
(=WS)
conditions.
Figure 3. Pressure distribution of the left foot. * indicates statistically significant differences. Black
boxes for the without stroller (=NS) and white boxes for with stroller (=WS) conditions.
J.J.Funct.
Funct. Morphol.
Morphol. Kinesiol.
Kinesiol. 2016,
2016, 1,
1, 314–321
314-321
318
318
Pressure Distribution Right
J. Funct. Morphol. Kinesiol. 2016, 1, 314-321
1.20
*
Pressure Distribution Right
0.80 1.20
0.40
Pressure [N/cm²*s]
Pressure [N/cm²*s]
1.00
0.60
0.20
0.00
318
*
*
0.80
*
0.86 0.83
0.40
*
0.61 0.61
0.60
0.86 0.83
0.40 0.39
0.37 0.36
0.61 0.61
0.20
0.40 0.39
forefeet
metatarsus
0.37 0.36
heel
*
*
1.00
inner edge
0.52 0.51
0.52 0.51
outer edge
*
0.58 0.56
0.58 0.56
total
0.00
forefeet
metatarsus
edge
outer
edge differences.
total
Figure 4. Pressure distribution
of the right foot.heel
* indicatesinner
statistically
significant
Black
boxes
for
the
without
stroller
(=NS)
and
white
boxes
for
with
stroller
(=WS)
conditions.
Figure 4. Pressure distribution of the right foot. * indicates statistically significant differences. Black
boxesFigure
for the
without stroller (=NS) and white boxes for with stroller (=WS) conditions.
4. Pressure distribution of the right foot. * indicates statistically significant differences. Black
Withboxes
regard
to the right foot, significantly decreased pressure was found in the condition with
for the without stroller (=NS) and white boxes for with stroller (=WS) conditions.
2 ¨s ˘ 0.198
With regard
to thetoright
foot, significantly
found
in the
condition
with
the stroller
compared
the condition
without decreased
the strollerpressure
for the was
forefoot
(0.856
N/cm
2
2
the stroller
compared
the
without
the
forouter
thewas
forefoot
(0.856
N/cm
∙s ±N/cm
0.198 2vs.
With
regardN/cm
toto
the
right
significantly
decreased
pressure
found(0.52
in the˘
condition
with
¨s
vs.
0.827
˘
0.196
¨s;condition
pfoot,
= 0.01;
dCohen
=stroller
0.147),
edge
0.135
2
2
2N/cm
2∙s
stroller
compared
to¨s;thepdcondition
without
the=
stroller
for±inner
the
forefoot
0.198
vs. 22∙s;
0.827the
±0.512
0.196
∙s; p = 0.01;
Cohen
= 0.147),
outer
edge
(0.52
0.135
N/cm
vs.N/cm
0.512
±±0.135
N/cm
vs.
˘N/cm
0.135
= 0.01;
dCohen
0.059),
edge(0.856
(0.61
˘ ∙s0.155
N/cm
¨s
2∙s;
2∙s vs. 0.512
2∙s;
2
2
0.827
±
0.196
N/cm
p
=
0.01;
d
Cohen
=
0.147),
outer
edge
(0.52
±
0.135
N/cm
±
0.135
N/cm
2
2
p = 0.01;
Cohen
= 0.059),
(0.61d±Cohen
0.155=N/cm
vs. 0.60
± 0.130
N/cm(0.58
∙s; p =˘0.03;
dCohen
= 0.07)
vs.
0.60d˘
0.130
N/cm inner
¨s; p edge
= 0.03;
0.07)∙sand
total
pressure
0.114
N/cm
¨s
2∙s vs. 0.60 ± 0.130 N/cm2∙s; p = 0.03; dCohen = 0.07)
p = 0.01;
dCohen N/cm
= (0.58
0.059),
inner
± 0.155
2±¨s;
2d
and 0.565
total
pressure
0.114
N/cm
∙sCohen
vs.
0.565
± 0.106
N/cm
= 0.01;
0.136),
not 2for
vs.
˘ 0.106
p =edge
0.01;(0.61
= N/cm
0.136),
but
not2∙s;
forp the
heeldCohen
(0.37= ˘
0.189but
N/cm
¨s
2∙s; p = 0.01; dCohen = 0.136), but not for
and total pressure (0.58
0.114 N/cm2∙s vs. 0.565 ± 0.106
2 ¨s;±2∙s
2 ¨s±
2∙s; p N/cm
the heel
± 0.189
N/cm
=
0.27;
d
Cohen = 0.054)
and
metatarsus
(0.40
vs.
0.36(0.37
˘ 0.183
N/cm
p2 vs.
= 0.36
0.27;± 0.183
dCohenN/cm
= 0.054)
and
metatarsus
(0.40
˘
0.143
N/cm
the heel2 (0.37 ± 0.189
N/cm ∙s vs. 0.36
± 0.183 N/cm2∙s; p = 0.27; dCohen = 0.054) and metatarsus (0.40 ±
2 ¨s;
2∙s; p =
0.143
∙s vs.
0.39
± p0.139
N/cm
= 0.071).
0.07; dCohen
0.071). pressure
The plantar
pressure distributions
of
vs.
0.39N/cm
˘ 0.139
N/cm
= 0.07;
dCohen
The =plantar
distributions
of the left foot
2
2
0.143 N/cm ∙s vs. 0.39 ± 0.139 N/cm ∙s; p = 0.07; dCohen = 0.071). The plantar pressure distributions of
20.211
2 ¨s;
2∙s
the left
foot
also
showed
significant
decreases
for
the
forefoot
(0.872
±
N/cm
vs.
0.820
±
0.196
also
showed
significant
decreases
for
the
forefoot
(0.872
˘
0.211
N/cm
¨s
vs.
0.820
˘
0.196
N/cm
the left foot also showed significant decreases for the forefoot (0.872 ± 0.211 N/cm2∙s vs. 0.820 ± 0.196
2 ¨s vs.
2 2∙s;pp== 0.01;
2∙s; d
2
p2Cohen
= 0.00;
d
Cohen
= inner
0.255),
inner
edge
0.149
N/cm
0.617
± 0.147
N/cm
pN/cm
= 0.00;
0.255),
edge
(0.643
˘
0.149
N/cm
0.617
˘
0.147
N/cm
2∙s ∙s
2∙s; p¨s;
N/cm
∙s;
p ==
0.00;
dCohen
= 0.255),
inner
edge (0.643
(0.643
±± 0.149
N/cm
vs.vs.
0.617
± 0.147
N/cm
= 0.01;
2
2
2
2
2∙s
2∙s; ∙s;
Cohend=
outer
edge
(0.528
±˘±0.149
vs.
0.495
0,125
N/cm
= 0.00;
dCohen
= 0.24),
total
ddCohen
=0.176),
0.176),
outer
edge
(0.528
0.149
N/cm
0.495
˘ 0,125
N/cm
¨s;
pd
=Cohen
0.00;
dCohen
= 0.24),
Cohen
= 0.176),
outer
edge
(0.528
0.149N/cm
N/cm
∙s ¨s
vs.vs.
0.495
±±0,125
N/cm
p =p0.00;
= 0.24),
total
2 ¨s vs.
2∙sN/cm
2∙s;
2∙s
pressure
(0.586
± 0.116
vs.vs.0.557
±±0.110
N/cm
∙s;pp==0.00;
0.00;dCohen
d2Cohen
==0.257),
metatarsus
(0.402
pressure
(0.586
± 0.116
N/cm
0.557
0.110
N/cm
andand
(0.402
total
pressure
(0.586
˘N/cm
0.116
0.557
˘ 20.110
N/cm
0.00;
dmetatarsus
=
0.257),
and
¨s;= p0.257),
Cohen
2∙s vs. 0.389 ± 0.134
2∙s; p = 0.027; dCohen = 0.094),
2
2
2
2
±
0.142
N/cm
N/cm
but
not
for
the
heel
(0.643
±
0.149
± 0.142 N/cm
∙s vs.˘0.389
0.134 N/cm
∙s; p =˘0.027;
Cohen = 0.094),
but notdCohen
for the
heel (0.643
± 0.149
metatarsus
(0.402
0.142±N/cm
¨s vs. 0.389
0.134dN/cm
¨s; p = 0.027;
= 0.094),
but not
for
2∙s vs. 0.617 ± 0.147 N/cm
2∙s; p = 0.28; dCohen = 0.176).2Furthermore, the double-step length was
2 ¨s
N/cm
2∙s (0.643
2∙s;
N/cm
vs.
0.617
± 0.147
N/cm
p =0.617
0.28;˘d0.147
Cohen =N/cm
0.176).¨s;
Furthermore,
the double-step
length was
the
heel
˘ 0.149
N/cm
vs.
p = 0.28; dCohen
= 0.176). Furthermore,
significantly
reduced
in the
“withstroller”
stroller”
condition
compared
toto
without
thethe
stroller
(1.691
± 0.29
significantly
reduced
inwas
the
“with
condition
compared
without
stroller
(1.691
±m
0.29 m
the
double-step
length
significantly
reduced
in the
“with stroller”
condition
compared
to without
vs. 1.665 ± 0.27 m; p = 0.01; dCohen = 0.093) (see Figure 5).
vs. stroller
1.665 ± 0.27
m;˘p 0.29
= 0.01;
dCohen
= 0.093)
(see
5).dCohen = 0.093) (see Figure 5).
the
(1.691
m vs.
1.665
˘ 0.27
m; Figure
p = 0.01;
Double Step Length
DOUBLE STEP LENGTH (M)
DOUBLE STEP LENGTH (M)
Double Step Length
2.050
2.000
2.050
1.950
2.000
1.900
1.950
1.850
1.900
1.800
1.850
1.750
1.800
1.700
1.750
1.650
1.700
1.600
1.650
1.550
1.500
1.600
*
*
1.691
1.691
1.665
1.665
NS
WS
1.550
1.500 the without stroller (=NS) and with stroller (=WS) conditions.
Figure
5. Double-step
length
Figure
5. Double-step
lengthfor
for the without stroller (=NS) and with stroller (=WS) conditions. *
NS
WS
* indicates
statistically
significant
indicates
statistically
significantdifferences.
differences.
Figure 5. Double-step length for the without stroller (=NS) and with stroller (=WS) conditions. *
indicates statistically significant differences.
J. Funct. Morphol. Kinesiol. 2016,
2016, 1,
1, 314-321
314–321
319
The Spearman test revealed no correlation between the decrease in plantar pressure and the
The
Spearman
nofoot
correlation
between
the(see
decrease
in6).
plantar pressure and the stride
stride length
for thetest
leftrevealed
and right
(0.2906 and
0.0219)
Figure
length for the left and right foot (0.2906 and 0.0219) (see Figure 6).
Figure 6. Relationship of the shift of running with and without a jogging stroller in stride length and
Figure 6. Relationship of the shift of running with and without a jogging stroller in stride length and
foot pressure in the left and right foot. The correlation for the left foot is 0.29 and 0.022 for the right foot.
foot pressure in the left and right foot. The correlation for the left foot is 0.29 and 0.022 for the right
foot.
4. Discussion
4. Discussion
As stated previously, there has been no study—to our knowledge—which had determined changes
in plantar
pressure
when running
a stroller.
Before weour
discuss
our findings, we had
wantdetermined
to describe
As stated
previously,
there with
has been
no study—to
knowledge—which
the
limitations
of
our
study.
(1)
The
tests
were
carried
out
on
a
treadmill.
As
several
studies
have
changes in plantar pressure when running with a stroller. Before we discuss our findings, we want
shown,
treadmill
walking
[10]
and
running
[11,12]
are
not
identical
to
the
normal
over
ground
situation.
to describe the limitations of our study. (1) The tests were carried out on a treadmill. As several
We
still have
decided
to use
a treadmill,
as it[10]
offers
possibility
setnot
theidentical
runningtospeed.
Therefore,
studies
shown,
treadmill
walking
andthe
running
[11,12]toare
the normal
over
only
the
combination
of
cadence
and
step
length
may
be
altered
if
subjects
do
not
move
forward
or
ground situation. We still decided to use a treadmill, as it offers the possibility to set the running
backward
on the treadmill,
which was controlled
in step
the tests;
(2)may
Thebe
time
of data
collection
speed. Therefore,
only the combination
of cadencefor
and
length
altered
if subjects
dowas
not
limited
to
30
s
as
the
measurement
devices
used
do
not
support
longer
time
periods.
move forward or backward on the treadmill, which was controlled for in the tests; (2) The time of
resultswas
showlimited
significantly
total
plantar pressure
for both
feet,longer
with larger
data Our
collection
to 30 slower
as the
measurement
devices
used left
do and
not right
support
time
decreases
periods. for the left feet. Moreover, stride length was significantly reduced while running with
a jogging
stroller.
As the
literaturelower
reveals,
several
have
anright
inverse
Our results
show
significantly
total
plantarstudies
pressure
forsuggested
both left and
feet,relationship
with larger
between
frequency,
center of mass
excursion and
ground
reaction
force with
(GRF),
decreasesthe
forstride
the left
feet. Moreover,
stride(COM)
lengthvertical
was significantly
reduced
while
running
a
respectively
[13–15].
Schubert
and
Kempf
[13]
published
a
systematic
review
on
the
influence
of
stride
jogging stroller. As the literature reveals, several studies have suggested an inverse relationship
frequency
andstride
lengthfrequency,
on runningcenter
mechanics,
in which
reported
a significantly
inverse
relationship
between the
of mass
(COM)they
vertical
excursion
and ground
reaction
force
of
reduced
peak vertical
GRF
and COM
excursion
when
the cadence
was increased
while
(GRF),
respectively
[13–15].
Schubert
and vertical
Kempf [13]
published
a systematic
review
on the influence
running
over ground
well as
a treadmill.
Thompson
and
Gutman
[14]a were
able to show
a
of stride frequency
andaslength
onon
running
mechanics,
in which
they
reported
significantly
inverse
significant
main
effect
of
stride
length
on
the
anterior-posterior
and
vertical
GRFs
during
running
over
relationship of reduced peak vertical GRF and COM vertical excursion when the cadence was
ground.
Heiderscheit
and Chumanov
[15]
similar
results forand
running
on a[14]
treadmill
increasedMoreover,
while running
over ground
as well as
onreported
a treadmill.
Thompson
Gutman
were
concerning
the
inversely
related
COM
to
the
stride
length.
Furthermore,
statistically
significant
lower
able to show a significant main effect of stride length on the anterior-posterior and vertical GRFs
peak
pressure
the ground.
heel, toes
and midfoot
have been
reported
[16,17].
though
during
runningfor
over
Moreover,
Heiderscheit
and
Chumanov
[15]However,
reported even
similar
resultsa
correlation
between
a
decrease
in
stride
length
and
total
foot
pressure
could
have
been
expected,
it is
for running on a treadmill concerning the inversely related COM to the stride length. Furthermore,
very
low
to
non-existent
(see
Figure
6)
in
our
data.
Therefore,
we
conclude
that
there
must
be
other
statistically significant lower peak pressure for the heel, toes and midfoot have been reported [16,17].
influences
besides
a reduction
in step
length awhich
result
in thelength
decrease
plantar
However, even
though
a correlation
between
decrease
in stride
andoftotal
foot pressure
pressure when
could
running
with
a
stroller.
have been expected, it is very low to non-existent (see Figure 6) in our data. Therefore, we conclude
Batenimust
and be
Maki
[18]influences
publishedbesides
a systematic
reviewinonstep
assistive
balance
mobility
that there
other
a reduction
lengthdevices
which for
result
in theand
decrease
of
in
whichpressure
the authors
have
highlighted
changes induced through the assistive devices on the COM
plantar
when
running
with athe
stroller.
J. Funct. Morphol. Kinesiol. 2016, 1, 314–321
320
and the base of support (BOS). The use of a crutch or cane on the contralateral side of an injured leg,
for example, leads to a forward shift of COM, an increase in BOS and—as this is the purpose of using
an assistive device in the first place—a reduction in plantar pressure of the injured leg. Obviously,
a stroller cannot be regarded as an assistive device for balance and mobility, but the effects seem to be
similar. However, in our study the participants also had to keep the stroller in a straight line. Therefore,
a certain amount of pressure on the handlebar had to be applied, which explains self-reports of having
to increase the activation of muscles of the right shoulder. Further, we observed a forward shift of the
trunk towards the handlebar.
Moreover, Ishikura [8] reported a correlation between weight-bearing and hip joint flexion angles
and O’Sullivan and Kieran [5] found an increase in hip flexion at initial contact, in pelvic tilt and in
forward lean of the trunk when running with a stroller. This does not necessarily mean that these
changes in kinematics induced the reduction in plantar pressure through weight-bearing, but it may
be part of the explanation.
In total, our results show statistically significant changes in plantar pressure, but we do not
think these are of clinical importance as the effect sizes are very low. Therefore, no specific training
recommendations for running with a stroller have to be made.
We suggest for future studies to measure the force applied on the handlebar of the stroller and to
determine the alterations in hip flexion, as this data might offer further insight into the underlying
mechanisms of the presented alterations.
Author Contributions: All of the authors (Christoph Mickel, Antonia Baltrusch, Fabian Holzgreve, Laura Maltry,
Hagen Hartmann, Michael Keiner and Klaus Wirth) worked together for research design, data analysis,
and writing the paper.
Conflicts of Interest: The authors declare no conflict of interest.
Abbreviations
The following abbreviations are used in this manuscript:
WS
NS
COM
GRF
BOS
with jogging stroller
no jogging stroller
center of mass
ground reaction force
base of support
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