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Acute Effects of Barefoot And Minimalist Footwear on Medial Tibiofemoral Compartment Loading During Running: A Statistical Parametric Mapping Approach

Authors:
Jonathan Sinclair at University of Central Lancashire
Jonathan Sinclair
Bobbie Butters at University of Central Lancashire
Bobbie Butters
Philip Stainton at University of Central Lancashire
Philip Stainton
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Abstract and Figures

The current investigation examined the effects of running barefoot and in minimalist footwear on medial tibiofemoral compartment loading, compared to conventional running trainers. Fifteen male runners ran over a force platform in five different footwear conditions (barefoot, Vibram five-fingers (Footwear A), Inov-8 (Footwear B) Nike-Free (Footwear C), and running trainer) whilst lower extremity kinematics were examined using a three-dimensional camera system. Medial compartment loading during the stance phase was explored using the knee adduction moment (KAM). In addition, the KAM instantaneous load rate was also calculated. Differences between footwear across the entire stance phase were examined using 1-dimensional statistical parametric mapping, whereas differences in discrete parameters were explored using one-way repeated measures ANOVA. Statistical parametric mapping revealed that Footwear B was associated with a significantly larger KAM compared to the running trainer from 15-20 and 25-30% of the stance phase and also Footwear C from 15-20% of the stance phase. The KAM instantaneous load rate was significantly larger in the barefoot (210.69 Nm/kg/s), Footwear A (200.23 Nm/kg/s) and Footwear B (186.03 Nm/kg/s) conditions in comparison to Footwear C (100.88 Nm/kg/s) and running trainers (92.70 Nm/kg/s). The findings from this study indicate that running barefoot and in minimalist footwear with the least midsole interface may place runners at increased risk of medial compartment knee OA, although further exploration using habitual barefoot / minimalist footwear users is required.
KAM curves during the stance phase as a function of footwear (black = barefoot, grey = running trainer, grey dash = Footwear A, black dot = Footwear B, grey dot = Footwear C), (ADD = adduction).
KAM curves during the stance phase as a function of footwear (black = barefoot, grey = running trainer, grey dash = Footwear A, black dot = Footwear B, grey dot = Footwear C), (ADD = adduction).
… 
Comparison of the KAM across the stance phase in all footwear conditions. SPM (F) denotes the F value, and critical thresholds for statistical significance are denoted via the horizontal dotted line.
Comparison of the KAM across the stance phase in all footwear conditions. SPM (F) denotes the F value, and critical thresholds for statistical significance are denoted via the horizontal dotted line.
… 
Comparison of the KAM across the stance phase, in barefoot vs. running trainer (a.), barefoot vs. Footwear B (b.), barefoot vs. Footwear C (c.) barefoot vs. Footwear A (d.). Positive values indicate that the barefoot KAM values exceed those in the other footwear conditions; SPM (t) denotes the t value and critical thresholds for statistical significance are denoted via the horizontal dotted lines.
Comparison of the KAM across the stance phase, in barefoot vs. running trainer (a.), barefoot vs. Footwear B (b.), barefoot vs. Footwear C (c.) barefoot vs. Footwear A (d.). Positive values indicate that the barefoot KAM values exceed those in the other footwear conditions; SPM (t) denotes the t value and critical thresholds for statistical significance are denoted via the horizontal dotted lines.
… 
Comparison of the KAM across the stance phase, in running trainers vs. Footwear C (a.), running trainers vs. Footwear A (b.) and Footwear C vs. Footwear A (c.). Positive values indicate that the running trainer / Footwear C KAM values exceed those in the other footwear conditions; SPM (t) denotes the t value and critical thresholds for statistical significance are denoted via the horizontal dotted lines.
Comparison of the KAM across the stance phase, in running trainers vs. Footwear C (a.), running trainers vs. Footwear A (b.) and Footwear C vs. Footwear A (c.). Positive values indicate that the running trainer / Footwear C KAM values exceed those in the other footwear conditions; SPM (t) denotes the t value and critical thresholds for statistical significance are denoted via the horizontal dotted lines.
… 
Comparison of the KAM across the stance phase, in Footwear B vs. running trainers (a.), Footwear B vs. Footwear C (b.) and Footwear B vs. Footwear A (c.). Positive values indicate that the Footwear B KAM values exceed those in the other footwear conditions; SPM (t) denotes the t value and critical thresholds for statistical significance are denoted via the horizontal dotted lines.
Comparison of the KAM across the stance phase, in Footwear B vs. running trainers (a.), Footwear B vs. Footwear C (b.) and Footwear B vs. Footwear A (c.). Positive values indicate that the Footwear B KAM values exceed those in the other footwear conditions; SPM (t) denotes the t value and critical thresholds for statistical significance are denoted via the horizontal dotted lines.
… 
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Journal of Human Kinetics volume 65/2018, 35-44 DOI: 10.2478/hukin-2018-0037 35
Section I – Kinesiology
1 - Centre for Applied Sport & Exercise Sciences, University of Central Lancashire, Lancashire, UK.
.
Authors submitted their contribution to the article to the editorial board.
Accepted for printing in the Journal of Human Kinetics vol. 65/2018 in December 2018.
Acute Effects of Barefoot And Minimalist Footwear on Medial
Tibiofemoral Compartment Loading During Running:
A Statistical Parametric Mapping Approach
by
Jonathan Sinclair1, Bobbie Butters1, Philip Stainton1
The current investigation examined the effects of running barefoot and in minimalist footwear on medial
tibiofemoral compartment loading, compared to conventional running trainers. Fifteen male runners ran over a force
platform in five different footwear conditions (barefoot, Vibram five-fingers (Footwear A), Inov-8 (Footwear B) Nike-
Free (Footwear C), and running trainer) whilst lower extremity kinematics were examined using a three-dimensional
camera system. Medial compartment loading during the stance phase was explored using the knee adduction moment
(KAM). In addition, the KAM instantaneous load rate was also calculated. Differences between footwear across the
entire stance phase were examined using 1-dimensional statistical parametric mapping, whereas differences in discrete
parameters were explored using one-way repeated measures ANOVA. Statistical parametric mapping revealed that
Footwear B was associated with a significantly larger KAM compared to the running trainer from 15-20 and 25-30% of
the stance phase and also Footwear C from 15-20% of the stance phase. The KAM instantaneous load rate was
significantly larger in the barefoot (210.69 Nm/kg/s), Footwear A (200.23 Nm/kg/s) and Footwear B (186.03 Nm/kg/s)
conditions in comparison to Footwear C (100.88 Nm/kg/s) and running trainers (92.70 Nm/kg/s). The findings from
this study indicate that running barefoot and in minimalist footwear with the least midsole interface may place runners
at increased risk of medial compartment knee OA, although further exploration using habitual barefoot / minimalist
footwear users is required.
Key words: biomechanics, footwear, running, knee, overuse injury.
Introduction
Running is associated with an array of
physiological benefits; however, runners are
renowned for their susceptibility to chronic
pathologies (Taunton et al., 2002). As many as
80% of runners will experience a chronic injury
every year (van Gent et al., 2007).
The knee joint is the most susceptible
musculoskeletal structure to chronic pathologies
in runners (van Gent et al., 2007). Tibiofemoral
pathologies account for up to 16.8% of all knee
injuries (Taunton et al., 2002) and the initiation of
knee osteoarthritis (OA) is mediated by
mechanical stimuli (Brandt et al., 2008). The
pathogenesis of tibiofemoral overuse injuries
relates to the magnitude and frequency of the
loads experienced by the joint during running,
which represent the initiating mechanism that
causes the onset of knee OA (Miyazaki et al.,
2002). The medial aspect of the tibiofemoral joint
is significantly more susceptible to injury than the
lateral compartment (Wise et al., 2012). Contact
loading at the tibiofemoral joint is mediated via
the knee adduction moment (KAM). The KAM is
frequently utilized as a pseudo measure of medial
tibiofmeoral contact loading (Birmingham et al.,
2007; Kumar et al., 2017; Lynn et al., 2007), and the
peak KAM as well as the loading rate of the KAM
have been cited as important predictors of
radiographic knee OA (Miyazaki et al., 2002;
Morgenroth et al., 2014).
36 Acute effects of barefoot and minimalist footwear on medial tibiofemoral compartment loading during running
Journal of Human Kinetics - volume 65/2018 http://www.johk.pl
Given their prevalence and debilitating
nature, numerous strategies have been
investigated in clinical research, in an attempt to
attenuate the risk of knee pathologies in runners.
Barefoot running has received significant
attention in biomechanical literature; based on the
proposition that running without shoes may be
associated with a reduced incidence of chronic
pathologies (Lieberman et al., 2010). The
popularity of barefoot running lead has led to the
introduction of minimalist footwear, designed to
transfer the prospective benefits of running
barefoot into a shod condition. Previous analyses
in relation to the knee joint have shown
unequivocally that running barefoot and in
minimalist footwear attenuates the loads
experienced by the patellofemoral joint (Bonacci
et al., 2014; Sinclair, 2014; Sinclair et al., 2016).
However, there has yet to be any published
investigation exploring the effects of running
barefoot / in minimalist footwear on medial
tibiofemoral compartment loading.
Therefore, the aim of the current
investigation was to examine the effects of
running barefoot and in minimalist footwear on
medial compartment loading during the stance
phase, in relation to conventional running
trainers. This was explored predominantly using
an innovative statistical procedure known as
statistical parametric mapping (SPM), whereby
statistical differences between footwear were
explored across the entire stance phase as
opposed to at individual discrete time points. An
investigation of this nature may provide
important information regarding the most
appropriate footwear for runners susceptible to
medial compartment knee OA.
Methods
Participants
Fifteen healthy male runners (age 25.30 ±
4.69 years, body height 1.78 ± 0.10 m and body
mass 71.34 ± 5.82 kg) volunteered to take part in
this study. Participants were identified as
recreational runners, who trained a minimum of 3
times/week completing a minimum of 35
km/week. Pilot analyses showed that all runners
exhibited a habitual rearfoot strike pattern, as
they demonstrated an impact peak in their
vertical ground reaction force curve, when
running in their own footwear. The participants
provided written informed consent and the
procedure was approved by an institutional
ethical panel.
Experiential footwear
Footwear examined in this study
consisted of a running trainer (New Balance 1260
v2), Vibram five-fingers (M108 Classic –
Henceforth termed Footwear A), Inov-8 (Evoskin
– Henceforth termed Footwear B) and Nike-Free
(5.0 – Henceforth termed Footwear C) in sizes 8–
10 men's UK (Figure 1). The running trainer had a
mean mass of 0.285 kg, heel thickness of 25 mm
and heel drop of 14 mm, Footwear A an average
mass of 0.167 kg, heel thickness of 7 mm and a
heel drop of 0 mm, Footwear B an average mass
of 0.100 kg, heel thickness of 4 mm and a heel
drop of 0 mm and Footwear C an average mass of
0.240 kg, heel thickness of 23 mm and a heel drop
of 13 mm
Procedures
Participants ran at 4.0 m/s ± 5%, striking a
piezoelectric force platform (Kistler, Kistler
Instruments Ltd) with their right (dominant) foot.
Running velocity was monitored using infrared
timing gates (Newtest, Oy Finland). The stance
phase was delineated as the duration over which
>20 N vertical force was applied to the force
platform. Runners completed five successful trials
in each footwear condition in a counterbalanced
manner. Kinematic data was captured at 250 Hz
via an eight camera motion capture system
(Qualisys Medical AB, Goteburg, Sweden).
Lower extremity segments were modelled
in 6 degrees of freedom using the calibrated
anatomical systems technique (Cappozzo et al.,
1995). Lower extremity segments were delineated
in accordance with those of Sinclair (2014). Static
calibration trials were obtained in each footwear
allowing the anatomical markers to be referenced
in relation to the tracking markers/clusters.
Processing
Dynamic trials were digitized using
Qualisys Track Manager then exported as C3D
files to Visual 3D (C-Motion, Germantown, USA).
Ground reaction force and kinematic data were
smoothed using cut-off frequencies of 50 and 12
Hz with a low-pass Butterworth 4th order zero-
lag filter (Sinclair, 2014). Knee joint kinetics were
computed using Newton–Euler inverse-dynamics,
allowing net knee joint moments to be calculated.
Medial tibiofemoral compartment loading was
by Jonathan Sinclair et al. 37
© Editorial Committee of Journal of Human Kinetics
examined using the KAM during the stance
phase.
The KAM magnitude was normalized by
dividing by body mass (Nm/kg). Following this
KAM data for all participants in each footwear
during the stance phase was extracted and time
normalized to 101 data points. In addition, the
KAM instantaneous load rate (Nm/kg/s) was
determined the maximum slope in the KAM
computed between each frame.
Statistical analyses
Differences in the KAM across the entire
stance phase were examined using 1-dimensional
SPM with MATLAB 2017a (MATLAB,
MathWorks, Natick, USA), in accordance with
Pataky et al. (2016), using the source code
available at http://www.spm1d.org/. In agreement
with Pataky et al. (2013), SPM was implemented
in a hierarchical manner, analogous to one-way
ANOVA with post-hoc t-tests. Therefore, the
entire data-set was examined first, and if
statistical significance was reached then post-hoc
tests were conducted on each component
separately. For the KAM instantaneous load rate,
descriptive statistics of means, standard
deviations (SD) and 95% confidence intervals
(95% CI) were calculated for each footwear
condition. Differences between footwear in the
KAM instantaneous load rate were examined
using one-way repeated measures ANOVA,
following which post-hoc pairwise comparisons
were employed in the instance of a significant
main effect. Effect sizes were quantified, using
partial eta2 (pη2) and contextualized using the
following guidelines; very small = 0-0.1, small =
0.1-0.3, moderate = 0.3-0.5, large = 0.5-0.7, very
large = 0.7-0.9 and distinct = 0.9-1.0 (Hopkins,
1997). The alpha (α) level for statistical
significance was set at the 0.05 level throughout.
Statistical analysis of the KAM instantaneous load
rate was undertaken using SPSS v24.0 (SPSS Inc,
USA), and the minimum clinically important
difference (MCID) for this measurement was
considered to be 31.64 Nm/kg/s (2.3 * the pooled
standard error of this measurement) (Wyrwich,
2004).
Results
Figure 2 shows the KAM during the
stance phase as a function of the experimental
footwear. Figures 3-6 show the KAM compared
between footwear across the stance phase using
SPM. Table 1 presents differences in the KAM
instantaneous load rate function of different
footwear.
Statistical parametric mapping
The analysis of the overall data set using
SPM revealed significant differences between
conditions and thus post-hoc investigation
between individual footwear was required
(Figure 3). This revealed that the KAM was
significantly larger (p < 0.001) during barefoot
running in comparison to Footwear B, in the
period from 75-85% of the stance phase (Figure
4b). In addition, it was also shown that the KAM
was significantly larger (p < 0.001) in Footwear C
in relation to the running trainer in the period
from 20-25% of the stance phase (Figure 5a).
Finally, the Footwear B was associated with a
significantly larger KAM compared to the
running trainer (p = 0.031 & p = 0.045) from 15-20
and 25-30% of the stance phase (Figure 6a) and
also Footwear C (p = 0.042) from 15-20% of the
stance phase (Figure 6b).
KAM instantaneous load rate
A main effect (p < 0.05, pη2 = 0.62) was also
observed for the KAM instantaneous load rate.
Post-hoc pairwise comparisons showed that the
KAM instantaneous load rate was significantly
larger in the barefoot (p = 0.0002 & 0.0001),
Footwear A (p = 0.000003 & 0.000007) and
Footwear B (p = 0.00003 & 0.00001) in comparison
to Footwear C and running trainer (Table 1).
Discussion
The aim of the current investigation was
to explore the effects of running barefoot and in
minimalist footwear on medial compartment
loading compared to conventional running
trainers using a SPM approach. To the authors
knowledge this is the first quantitative
examination of the effects of running barefoot and
in minimalist footwear on medial tibiofemoral
loading in relation to conventional running
footwear.
Tibiofemoral pathologies are common
chronic pathologies in runners (Taunton et al.,
2002). Exploration of the KAM across the entire
stance phase using SPM showed that Footwear B
exhibited a significantly increased KAM at 15-20
and 25-30% of the stance phase, in relation to
Footwear C and running trainers.
38 Acute effects of barefoot and minimalist footwear on medial tibiofemoral compartment loading during running
Journal of Human Kinetics - volume 65/2018 http://www.johk.pl
Table 1
Knee adduction moment parameters (Mean, SD’s & 95% CI) as a function of the different experimental footwear.
Barefoot Footwear A Footwear B Footwear C Running
Trainer
KAM
instantaneous load
rate (Nm/kg/s)
210.69
AB 84.90 200.23
AB 57.57 186.03
AB 62.11 100.88 38.81 92.70 23.03
MCID = 31.34 Nm/kg/s
A = significantly different from Running Trainers
B = significantly different from Footwear C
Figure 1
Experimental footwear (a. = running trainer, b. = Footwear B, c. = Footwear A & d. = Footwear C).
by Jonathan Sinclair et al. 39
© Editorial Committee of Journal of Human Kinetics
Figure 2
KAM curves during the stance phase as a function of footwear (black = barefoot,
grey = running trainer, grey dash = Footwear A, black dot = Footwear B,
grey dot = Footwear C), (ADD = adduction).
Figure 3
Comparison of the KAM across the stance phase in all footwear conditions.
SPM (F) denotes the F value,
and critical thresholds for statistical significance are denoted via the horizontal dotted line.
40 Acute effects of barefoot and minimalist footwear on medial tibiofemoral compartment loading during running
Journal of Human Kinetics - volume 65/2018 http://www.johk.pl
Figure 4
Comparison of the KAM across the stance phase, in barefoot vs. running trainer (a.),
barefoot vs. Footwear B (b.), barefoot vs. Footwear C (c.) barefoot vs. Footwear A (d.).
Positive values indicate that the barefoot KAM values exceed those
in the other footwear conditions;
SPM (t) denotes the t value and critical thresholds for statistical significance
are denoted via the horizontal dotted lines.
by Jonathan Sinclair et al. 41
© Editorial Committee of Journal of Human Kinetics
Figure 5
Comparison of the KAM across the stance phase, in running trainers vs. Footwear C (a.),
running trainers vs. Footwear A (b.) and Footwear C vs. Footwear A (c.).
Positive values indicate that the running trainer / Footwear C KAM values exceed those
in the other footwear conditions; SPM (t) denotes the t value and critical thresholds
for statistical significance are denoted via the horizontal dotted lines.
42 Acute effects of barefoot and minimalist footwear on medial tibiofemoral compartment loading during running
Journal of Human Kinetics - volume 65/2018 http://www.johk.pl
Figure 6
Comparison of the KAM across the stance phase, in Footwear B vs. running trainers (a.),
Footwear B vs. Footwear C (b.) and Footwear B vs. Footwear A (c.).
Positive values indicate that the Footwear B KAM values exceed those
in the other footwear conditions; SPM (t) denotes the t value and critical thresholds
for statistical significance are denoted via the horizontal dotted lines.
by Jonathan Sinclair et al. 43
© Editorial Committee of Journal of Human Kinetics
This is an interesting observation that was
likely caused by the peaks early in the KAM
waveform, which were present in Footwear B
(Figure 2). It is proposed that this is a reflection of
the increased rate at which the ground reaction
forces were experienced in Footwear B as Sinclair
et al. (2013) showed that this footwear condition
was associated with the highest rates of loading
even compared to running barefoot. Given the
proposed association between the magnitude of
the KAM and chronic tibiofemoral pathologies
(Birmingham et al., 2007), this indicates that
Footwear B may place runners at increased risk
during the early stance phase in relation to
Footwear C and the running trainer condition.
In addition, the current investigation also
revealed using SPM that the KAM was
significantly larger in Footwear C, in relation to
the running trainer from 20-25% of the stance
phase. This is similarly a potentially important
clinical observation as the KAM is strongly linked
to the aetiology of chronic medial tibiofemoral
pathologies (Birmingham et al., 2007). The current
study therefore indicates that Footwear C may
place runners at increased risk from tibiofemoral
pathology during the early stance compared to
the running trainer.
Importantly the current investigation also
revealed that a statistically significant main effect
with a large effect size was evident for the KAM
instantaneous loading rate. Specifically, it was
found that the KAM instantaneous rate of loading
was significantly greater in the barefoot, Footwear
A and Footwear B conditions. Importantly, it was
also shown that the statistical differences between
footwear exceeded the MCID. The KAM is an
effective measure of compressive medial
tibiofemoral compartment loading (Birmingham
et al., 2007), and the KAM rate of loading is an
important predictor of degenerative knee OA
(Morgenroth et al., 2012). Thus it appears that
running barefoot and in minimalist footwear with
the least midsole interface may accentuate the risk
of medial compartment knee OA in runners.
A limitation of the current investigation is
that only the acute effects of running in different
footwear were investigated. This limits the
generalizability of the findings in relation to those
who customarily run barefoot and in minimalist
footwear, thus it is prudent for the current
analysis to be repeated using a group of habitual
barefoot / minimalist footwear users before a
broad assertion regarding injury predisposition at
the tibiofemoral joint can be drawn. A further
potential drawback is that only male runners were
examined. Female runners have been shown to
exhibit distinct KAM profiles in relation to males
(Sinclair and Selfe, 2015). Thus further exploration
using a sample of female runners is a clear
requirement for future analyses.
Conclusion
In conclusion, although the effects of
barefoot and minimalist footwear have received
extensive attention, current knowledge regarding
differences in medial tibiofemoral loading when
running these different kinds of footwear is
lacking. Therefore, the current investigation
contributes to the biomechanical literature base by
exploring the KAM across the entire stance phase
when running barefoot and in different
minimalist footwear. The findings from this study
using SPM importantly showed that Footwear B
exhibited a significantly increased KAM during
the early stance phase, in relation to Footwear C
and running trainers. Furthermore, the KAM
loading rate was found to be significantly larger
when running barefoot and in minimalist
footwear with the least midsole interface. This
therefore indicates that these footwear conditions
may place runners at increased risk of medial
compartment knee OA, although further
exploration using habitual barefoot / minimalist
footwear users is required before a broader
assertion regarding injury predisposition at the
tibiofemoral joint can be drawn.
Acknowledgements
We thank Todd Pataky, Mark Robinson and Jos Vanrenterghem for their excellent website
(http://www.spm1d.org/) and for generously providing the source code for this experiment.
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Corresponding author:
Dr. Jonathan Sinclair
Centre for Applied Sport & Exercise Sciences
Faculty of Health and Wellbeing
University of Central Lancashire; Preston; Lancashire; PR1 2HE
... A total of 28 studies assessed running, 13 involving treadmill running and 15 surface running. Among these studies, ten focused on the effects of different shoes on running biomechanics, [9][10][11][12][13][14][15][16][17][18] three studies examined specific physical interventions, [19][20][21] three studies assessed various gait modifications, 22-24 three evaluated foot biomechanics, [25][26][27] two explored the effects of fatigue, 28,29 and two investigated studies the effects of sex. 30,31 Additionally, single studies examined the effects of different surfaces, 32 hamstring flexibility, 33 pertubations, 34 running with different loads, 35 and the differences between transition running and isolated running in triathlon Table 1). ...
... Additionally, one study evaluated the inter-individual and intra-individual variability during a squat (Table 4). 70 The median number of participants was 15 [9][10][11][12][13][14][15][16][17][18][19][20]. ...
... They examined the influence of fatigue 75 and sex 76 on force production, as well as the kinetics and kinematics of eccentric, quasi-isometric loading (Table 4). 77 The median number of participants was 17 [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. ...
Scoping Review of One-Dimension Statistical Parametric Mapping in Lower Limb Biomechanical Analysis
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Full-text available
  • Aug 2023
Background: Biomechanics is crucial in enhancing sports performance and preventing injury. Traditionally, discrete point analysis is used to analyze important kinetic and kinematic data points, reducing continuous data to a single point. One-dimensional Statistical Parametric Mapping (spm1d) offers a more comprehensive approach by assessing entire movement curves instead of isolated peak values. Nevertheless, spm1d is still underutilized in various sports and sports-related injuries. Purpose: To summarize the existing literature on the application of spm1d in sports biomechanics, including the kinetics and kinematics of the hip, knee, and ankle joints, as well as to identify gaps in the literature that may require further research. Methods: A scoping review was conducted, searching PubMed, Embase, Web of Science, and ProQuest databases. English peer-reviewed studies using SPM to assess lower limb kinetics or kinematics in different sports or sports-related injuries were included. In contrast, reviews, meta-analyses, conference abstracts, grey literature, and studies focusing on non-kinetic or kinematic outcomes were excluded. Results: The review yielded 139 papers, with an increased number of studies published in the last three years. Of these studies, 91 examined healthy individuals (64%), and 51 focused on injured populations (36%). Running (n=28), cutting (n=21), and jumping/landing (n=15) were the most common activities. The most prevalent sport-related injuries examined were anterior cruciate ligament rupture (n=21), chronic ankle instability (n=16), and hip-related pain (n=9). Research gaps include the underrepresentation of common sports and movements, small sample size, lack of studies in non-laboratory settings and varied active age groups, and absence of evaluations on the effects of protective sports gear other than shoes. Conclusion: The application of spm1d in sports biomechanics demonstrates diverse uses in sports performance, injury reduction, and rehabilitation. While spm1d shows promise in improving our understanding of sports biomechanics, there are still significant gaps in the literature that present future research opportunities.
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... Running footwear may play an important role in chronic injury prevention [13] and over the past 40 years significant innovations in running footwear technology have been made [14]. In recent years, minimal footwear, which does not feature high levels of cushioning or motion control features that are commonplace in conventional running shoes, has received considerable research attention [14,15]. Randomized controlled trials have importantly shown that long-term use of minimal footwear improved pain symptoms in elderly patients with existing knee OA [16] and prevented knee pain in runners preparing for a 10-kilometre event [17]. ...
... Several observational analyses have also examined running kinetics and kinematics in minimal and conventional footwear, although only limited analyses have examined their effects on the loads borne by the medial tibiofemoral joint. Sinclair et al. [15] showed that minimal footwear significantly increased the magnitude of the knee adduction moment, which is utilized as a quasi-measure of medial knee contact loading [18]. Finally, Sinclair et al. [19] using a musculoskeletal simulation-based approach, found that minimal footwear was associated with significant increases in medial tibiofemoral loading during early stance, compared to conventional footwear. ...
... In opposition to our hypotheses, the current study importantly showed using musculoskeletal simulation and contact mechanical modelling that medial tibiofemoral joint forces, stresses and strains were statistically larger in conventional compared to minimal footwear in the habitual minimal footwear group. This observation opposes those of Sinclair et al. [15] using the knee adduction moment and those of Sinclair et al. [19] using musculoskeletal simulation, which both showed that, in non-habitual minimal footwear users, the medial tibiofemoral force was larger in minimal footwear. Notably, the co-variate comparisons and regression models showed less-pronounced statistical differences between footwear in the habitual minimal footwear group and running velocity as a predictor of joint forces, stresses and strains (Supplementary Materials Section S6). ...
Effects of Running in Minimal and Conventional Footwear on Medial Tibiofemoral Cartilage Failure Probability in Habitual and Non-Habitual Users
Article
Full-text available
  • Dec 2022
This study examined the effects minimal and conventional running footwear on medial tibio-femoral cartilage mechanics and longitudinal failure probability. The current investigation ex-amined twenty males who habitually ran in minimal footwear and 20 males who habitually ran in conventional footwear. Kinematic data during overground running were collected using a motion capture system and ground reaction forces using a force plate. Medial tibiofemoral loading was examined using musculoskeletal simulation and cartilage failure probability via probabilistic modelling. In habitual minimal footwear users, peak medial tibiofemoral cartilage force, stress and strain were significantly greater in conventional (force=7.43BW, stress=5.12MPa & strain=0.30), compared to minimal footwear (force=7.11BW, stress 4.65MPa & strain=0.28), though no significant differences in these parameters were evident in non-habitual minimal footwear users (conventional: force=7.50BW, stress=5.05MPa & strain=0.30 and minimal: force=7.40BW, stress=4.77MPa & strain=0.29). However, in both habitual and non-habitual minimal footwear users’, probability of medial tibiofemoral cartilage failure was significantly greater in the conventional (habitual=47.19% & non-habitual=50.00%) compared to minimal footwear (habitual=33.18% & non-habitual=32.81%). The observations from this investigation show that in relation to minimal footwear, conventional footwear appear to have a negative influence on medial tibiofemoral cartilage health.
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... A total of 45 studies assessed running, 22 involving treadmill running and 23 surface running. Among these studies, 19 focused on the effects of different shoes on running biomechanics [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], three studies examined specific physical interventions [28][29][30][31], six evaluated the foot complex biomechanics [32][33][34][35][36][37], three studies assessed various gait modifications [38][39][40], three explored the effects of fatigue [41][42][43], and three investigated studies the effects of sex [44][45][46]. Single studies examined the effects of different surfaces [47], hamstring flexibility [48], perturbations [49], running with different loads [50], running speed [51], differences between transition running and isolated running in triathlon [52] and ACL risk profiles among healthy participants (Table 1) [53]. ...
... They examined the influence of fatigue [101] and sex [102] on force production, as well as the kinetics and kinematics of eccentric, quasi-isometric loading (Appendix 3). [103] The median number of participants was 17 [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. ...
One-dimension statistical parametric mapping in lower limb biomechanical analysis: A systematic scoping review
Article
  • Feb 2024
Background Biomechanics significantly impacts sports performance and injury prevention. Traditional methods like discrete point analysis simplify continuous kinetic and kinematic data, while one-dimensional Statistical Parametric Mapping (spm1d) evaluates entire movement curves. Nevertheless, spm1d's application in sports and injury research is limited. As no systematic review exists, we conducted a scoping systematic review, synthesizing the current applications of spm1d across various populations, activities, and injuries. This review concludes by identifying gaps in the literature and suggesting areas for future research. Research question What research exists using spm1d in sports biomechanics, focusing on the lower limbs, in what populations, and what are the current research gaps? Methods We searched PubMed, Embase, Web of Science, and ProQuest databases for the following search string: “(((knee) OR (hip)) OR (ankle)) OR (foot) OR (feet) AND (statistical parametric mapping)”. English peer-reviewed studies assessing lower limb kinetics or kinematics in different sports or sports-related injuries were included. Reviews, meta-analyses, conference abstracts, and grey literature were excluded. Results Our search yielded 165 papers published since 2012. Among these, 112 examined healthy individuals (67 %), and 53 focused on injured populations (33 %). Running (n = 45), cutting (n = 25), and jumping/landing (n = 18) were the most common activities. The predominant injuries were anterior cruciate ligament rupture (n = 21), chronic ankle instability (n = 18), and hip-related pain (n = 9). The main research gaps included the unbalanced populations, underrepresentation of common sports and sport-related injuries, gender inequality, a lack of studies in non-laboratory settings, a lack of studies on varied sports gear, and a lack of reporting standardization. Significance This review spotlights crucial gaps in spm1d research within sports biomechanics. Key issues include a lack of studies beyond laboratory settings, underrepresentation of various sports and injuries, and gender disparities in research populations. Addressing these gaps can significantly enhance the application of spm1d in sports performance, injury analysis, and rehabilitation.
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... People with knee OA have been shown to have higher ground reaction force (GRF) loading rates compared to healthy controls [20] and increased KAM loading rate has been correlated with increased medial tibiofemoral cartilage loss [21]. The type of shoe midsole has been shown to influence KAM loading rates [22], and stable and flat flexible shoes differ in sole structure [12]. However, given the limited relationship between the KAM and MTCF [23], the influence of shoe type on MTCF loading rates remains unclear. ...
... Stable supportive shoes are designed with thick, high pitched heels and cushioned soles, whereas flat flexible shoes have thin, low pitched heels and minimal shoe cushioning. Unfortunately, other research comparing the effects of stable supportive and flat flexible shoe styles on loading rates is limited to running in young, healthy populations [22], which makes direct comparisons with our findings in walking difficult given that loading rates during running are influenced by both foot strike pattern [49][50][51] and footwear style [20,50]. Furthermore, it is challenging to compare a clinical population aged �50 years with symptomatic medial knee OA and varus malalignment to a young population with asymptomatic knees due to disease-specific biomechanical strategies [20,25]. ...
Tibiofemoral contact force differences between flat flexible and stable supportive walking shoes in people with varus-malaligned medial knee osteoarthritis: A randomized cross-over study
Article
Full-text available
Objective To compare the effect of stable supportive to flat flexible walking shoes on medial tibiofemoral contact force (MTCF) in people with medial knee osteoarthritis and varus malalignment. Design This was a randomized cross-over study. Twenty-eight participants aged ≥50 years with medial knee osteoarthritis and varus malalignment were recruited from the community. Three-dimensional full-body motion, ground reaction forces and surface electromyograms from twelve lower-limb muscles were acquired during six speed-matched walking trials for flat flexible and stable supportive shoes, tested in random order. An electromyogram-informed neuromusculoskeletal model with subject-specific geometry estimated bodyweight (BW) normalized MTCF. Waveforms were analyzed using statistical parametric mapping with a repeated measures analysis of variance model. Peak MTCF, MTCF impulse and MTCF loading rates (discrete outcomes) were evaluated using a repeated measures multivariate analysis of variance model. Results Statistical parametric mapping showed lower MTCF in stable supportive compared to flat flexible shoes during 5–18% of stance phase (p = 0.001). For the discrete outcomes, peak MTCF and MTCF impulse were not different between the shoe styles. However, mean differences [95%CI] in loading impulse (-0.02 BW·s [-0.02, 0.01], p<0.001), mean loading rate (-1.42 BW·s ⁻¹ [-2.39, -0.45], p = 0.01) and max loading rate (-3.26 BW·s ⁻¹ [-5.94, -0.59], p = 0.02) indicated lower measure of loading in stable supportive shoes compared to flexible shoes. Conclusions Stable supportive shoes reduced MTCF during loading stance and reduced loading impulse/rates compared to flat flexible shoes and therefore may be more suitable in people with medial knee osteoarthritis and varus malalignment. Trial registration Australian and New Zealand Clinical Trials Registry ( 12619000622101 ).
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... Lower extremity segments were modelled in 6 degrees of freedom using the calibrated anatomical systems technique (Cappozzo, Catani, Leardini, Benedeti, & Della, 1995), using a marker configuration utilized previously to quantify the effects of orthoses patellofemoral joint kinetics (Sinclair, 2018). To define the anatomical frames of the pelvis, thigh, shank and foot retroreflective markers were positioned onto the iliac crest, anterior superior iliac spine (ASIS), and posterior super iliac spine (PSIS). ...
... In accordance with the recommendations of Crossley et al. (2017), the minimal clinically important difference (MCID) for the KOOS-PF scale was considered to be 16.4 points. For all of the other variables the MCID was considered to be 2.3 * the pooled standard error of measurement (Sinclair, Butters, & Stainton, 2018). ...
Effects of a 4-week intervention using semi-custom insoles on perceived pain and patellofemoral loading in targeted subgroups of recreational runners with patellofemoral pain
Article
  • Aug 2018
Objective: Explore the effects of a 4-week intervention using semi-custom insoles in recreational runners with patellofemoral pain. Design: Mixed methods. Participants: Seventeen (10 males and 7 females) recreational runners. Setting: Laboratory. Outcome measurements: Participants were separated into specific subgroups, then provided with a pair of semi-custom insoles, for a period of 4-weeks. Lower extremity kinetics/kinematics during running at 4.0 m/s were obtained. In addition, knee pain was examined using the Knee injury and Osteoarthritis Outcome Score-Patellofemoral scale (KOOS-PF). Data were collected before and after wearing the insoles for 4-weeks. Results: Significant improvements were shown for KOOS-PF in both subgroups (strong: (pre) = 63.84 & (post) = 71.49 and weak and tight: (pre) = 53.03 & (post) = 72.73), although only improvements in the weak and tight group exceeded the minimum clinically important difference (MCID). In addition, significant reductions in peak patellofemoral stress were shown in both subgroups (strong: (pre) = 6.82 & (post) = 6.39KPa/BW and weak and tight: (pre) = 7.66 & (post) = 6.28KPa/BW), although only reductions in the weak and tight group exceeded the MCID. Conclusions: Semi-custom insoles may be a mechanism to reduce patellofemoral pain symptoms in recreational runners from the weak and tight subgroup. It is proposed that this improvement was mediated through reductions in patellofemoral loading in this subgroup.
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... Recently, statistical parametric mapping (SPM) has been suggested as a suitable method to analyze one-dimensional data such as kinematic, kinetic or muscle activity time series and has shown to be superior to the over-simplification of discrete outcomes (Pataky et al., 2013). Even though SPM has been used to analyze minimalist footwear (Sinclair et al, 2018(Sinclair et al, , 2019 and the influence of footwear in prolonged running (Weir et al., 2019), no previous study used SPM to investigate gait kinematics or ground reaction forces while wearing military boots. Therefore, the main purpose of this study was to investigate the interaction between footwear (SBR and PU military boots) and load carriage (with and without load) on GRF and lower limb kinematics during the stance phase of gait using a SPM method. ...
Effects from loaded walking with polyurethane and styrene-butadiene rubber midsole military boots on kinematics and external forces: A statistical parametric mapping analysis
Article
  • Jul 2021
  • APPL ERGON
This study compared ground reaction forces (GRF) and lower limb two-dimensional (2D) kinematic waveforms, with and without load carriage, in military personnel walking in two different types of boots. Data were measured in 24-soldiers walking on a 10-m walkway under four randomized crossover trials: wearing two military boots (styrene-butadiene rubber midsole – SBR – 63 Shore A; and polyurethane midsole – PU – 48 Shore A); with and without a 15-kg backpack. GRF traditional parameters were evaluated by two-way ANOVAs. GRF and kinematic waveforms were assessed using a statistical parametric mapping (SPM) method (two-way ANOVA). No interaction effects were observed between footwear and load. GRF at the beginning of stance was lower while wearing the SBR boot condition compared to the PU boot condition. Load carriage increased trunk, hip, and knee flexion. The analyzed military boots did not affect movement patterns during loaded walking and the military boot with SBR midsole material reduced impact to a greater extent. The study demonstrated that the design and materials (e.g., midsole material and thickness) used in boot manufacturing can influence military boot performance.
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... The majority of research on barefoot running focuses on acute changes in altering footwear without regard to the runner's experience with barefoot or minimalist footwear running. Consequently, it is only possible to assess adjustments to novel conditions rather than assessing specific footwear (Becker et al., 2014;Jandová et al., 2019;Sinclair et al., 2018). Despite the fact that there was a considerable cushioned shoes during trail running (Fuller et al., 2015;Vercruyssen et al., 2016). ...
The effect of uneven terrain conditions during shod vs. barefoot running
Article
Full-text available
  • Mar 2021
Background: The majority of research on barefoot running focuses on acute changes in altering footwear without regard to the runner’s experience with barefoot or minimalist footwear running. Objective: The objective of this study was to compare the effect of footwear (standard cushioned running shoes, barefoot) and running surface (flat surface, uneven terrain) on gait in experienced runners using minimalist shoes. Methods: Terrain running was simulated by three custom-made mats with randomly placed firmly attached stones. Seven experienced trail runners participated in this study. All participants were forefoot strikers. Participants underwent three-dimensional kinematic and kinetic analysis consisting of five running trials in each combination of footwear and surface. A trial was successful when the participant maintained a velocity of 3.2 ± 0.16 m/s without targeting a force platform. Results: Uneven terrain conditions along with barefoot conditions led to significantly decreased peak moment of ankle plantarflexion (terrain: p = .041, footwear: p = .026) and decreased second peak of vertical ground reaction force in comparison with other conditions (terrain: p = .026, footwear: p = .004). Uneven terrain conditions also significantly decreased ankle dorsiflexion at initial contact with the ground for both footwear conditions (p = .021). Conclusions: We conjecture that net ankle moments could be decreased by barefoot running in terrain conditions in skilled forefoot runners. Experienced runners using minimalist shoes may incorporate trail running into their barefoot running regime without risk of higher Achilles tendon loading compared to even running.
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Measurement and reporting of footwear characteristics in running biomechanics: A systematic search and narrative synthesis of contemporary research methods
Article
  • Oct 2022
This review aimed to synthesise the methods for assessing and reporting footwear characteristics among studies evaluating the effect of footwear on running biomechanics. Electronic searches of Scopus®, EBSCO, PubMed®, ScienceDirect®, and Web of Science® were performed to identify original research articles of the effect of running footwear on running biomechanics published from 1st January 2015 to 7th October 2020. Risk of bias among included studies was not assessed. Results were presented via narrative synthesis. Eligible studies compared the effect of two or more footwear conditions in adult runners on a biomechanical parameter. Eighty-seven articles were included and data from 242 individual footwear were extracted. Predominantly, studies reported footwear taxonomy (i.e., classification) and manufacturer information, however omitted detail regarding the technical specifications of running footwear and did not use validated footwear reporting tools. There is inconsistency among contemporary studies in the methods by which footwear characteristics are assessed and reported. These findings point towards a need for consensus regarding the reporting of these characteristics within biomechanical studies to facilitate the conduct of systematic reviews and meta-analyses pertaining to the effect of running footwear on running biomechanics.
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A systematic review of the effect of running shoes on running economy, performance and biomechanics: analysis by brand and model
Article
  • Jun 2022
This systematic review aims to synthesise the effects of current shoe models in each shoe category and their specific features on running economy, performance and biomechanics. Electronic databases such as Web of Science, SPORTDiscuss, PubMed and Scopus were used to identify studies from 2015 to date. Due to the existing lack of consensus to define running shoes, only studies that specified the shoe brand and models used to assess their effect over runners with a certain level of fitness and training routine were included. Quality assessment of cross-sectional and intervention studies was conducted by three independent raters using a modified version of the Quality Index and the PEDro scale, respectively. A total of 36 articles were finally included, involving the analysis of 61 different shoe models over 10 different topics (i.e., running economy, running performance, spatiotemporal parameters, ground reaction forces, joint stiffness, achilles tendon, plantar pressure, tibiofemoral load, foot strike pattern and joint coordination). With this review, runners and practitioners in the field that are concerned about selecting a suitable shoe for performance, training, or injury prevention functionality have clear information about the effects of the current shoe models and their specific features.
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Effects of running with minimal and conventional footwear in habitual and non-habitual users: a musculoskeletal simulation and statistical parametric mapping based approach
Article
  • Oct 2019
The current investigation examined running biomechanics in minimal and conventional footwear in two groups of runners who either ran habitually in minimal footwear (habitual minimal footwear users) or habitually in conventional footwear (non-habitual minimal footwear users). We studied ten male non-habitual minimal footwear users and ten male habitual minimal footwear users, who were required to complete ≥35 km per week of training. Lower extremity joint loading was explored using a musculoskeletal simulation approach. Differences between conditions were examined using statistical parametric mapping and 2x2 mixed ANOVA. This study revealed via the strike index that minimal footwear caused a more anterior contact position in both groups (habitual: minimal=61.68% & conventional=46.48% /non-habitual: minimal=33.79% & conventional=22.61%), although non-habitual runners still adopted a rearfoot strike pattern. In addition, in non-habitual users minimal footwear increased tibial accelerations (habitual: minimal=6.35g & conventional=7.06g /non-habitual: minimal=9.54g & conventional=8.16g), loading rates (habitual: minimal=105.44BW/s & conventional=105.97BW/s /non-habitual: minimal=293.00BW/s & conventional=154.36BW/s) and medial tibiofemoral loading rates (habitual: minimal=196.17BW/s & conventional=274.96BW/s /non-habitual: minimal=274.96BW/s & conventional=212.57BW/s). Furthermore, minimal footwear decreased patellofemoral loading in both habitual (minimal=0.28BW·s & conventional=0.31BW·s) and non-habitual (minimal=0.26BW·s & conventional=0.29BW·s) users. Finally, Achilles tendon loading was larger in minimal footwear and in habitual runners (habitual: minimal=0.79BW·s & conventional=0.71BW·s /non-habitual: minimal=0.71BW·s & conventional=0.65BW·s) whereas iliotibial band strain rate was reduced in habitual (minimal=28.32%/s & conventional=30.30%/s) in relation to non-habitual (minimal=42.96%/s & conventional=42.87%/s) users. This study highlights firstly the importance of transitioning to minimal footwear and also indicates that post transition they may be effective in attenuating the biomechanical mechanisms linked to the aetiology of many chronic injuries.
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Frontal Plane Knee Mechanics and Early Cartilage Degeneration in People With Anterior Cruciate Ligament Reconstruction: A Longitudinal Study
Article
Full-text available
  • Nov 2017
  • AM J SPORT MED
Background: Abnormal frontal plane gait mechanics are known risk factors for knee osteoarthritis, but their role in early cartilage degeneration after anterior cruciate ligament reconstruction (ACLR) is not well understood. Hypothesis/Purpose: The objective was to evaluate the association of frontal plane gait mechanics with medial knee cartilage magnetic resonance (MR) relaxation times over 1 year in patients with ACLR and controls. It was hypothesized that (1) there will be an increase in frontal plane medial knee loading and medial knee MR relaxation times over time in the patients with ACLR, and (2) increases in frontal plane medial knee loading will be associated with an increase in medial knee MR relaxation times. Study design: Case-control study; Level of evidence, 3. Methods: Patients with ACLR (n = 37) underwent walking gait analyses and bilateral quantitative MR imaging (MRI) before surgery and at 6 and 12 months after ACLR. Healthy control participants (n = 13) were evaluated at baseline and 12 months. Gait variables included peak knee adduction moment (KAM), KAM impulse, and peak knee adduction angle. MRI variables included medial femur and medial tibia whole compartment and subregional T1ρ and T2 relaxation times. Statistical analyses included a comparison of changes over time for gait and MRI variables, correlations between changes in gait and MRI variables over time, and differences in change in MRI variables in patients who showed an increase versus decrease in KAM impulse. Results: There were significant increases in medial T1ρ (Δ 4%-11%) and T2 (Δ 2%-10%) relaxation times from baseline to 6 months for both knees in the ACLR group and in KAM (Δ 13%) for the injured knee. From baseline to 6 months, patients who had an increase in KAM impulse in the injured knee had a greater increase in medial T1ρ and T2 relaxation times as compared with those who did not have an increase in KAM impulse. Longitudinal changes for the control group were not significant. Conclusion: There is an increase in medial knee relaxation times over the first 6 months after ACLR. People with an increase in medial knee loading show an increase in medial knee relaxation times when compared with those who do not have an increase in medial knee loading over the first 6 months.
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Region-of-interest analyses of onedimensional biomechanical trajectories: Bridging 0D and 1D theory, augmenting statistical power
Article
Full-text available
  • Nov 2016
One-dimensional (1D) kinematic, force, and EMG trajectories are often analyzed using zero-dimensional (0D) metrics like local extrema. Recently whole-trajectory 1D methods have emerged in the literature as alternatives. Since 0D and 1D methods can yield qualitatively different results, the two approaches may appear to be theoretically distinct. The purposes of this paper were (a) to clarify that 0D and 1D approaches are actually just special cases of a more general region-of-interest (ROI) analysis framework, and (b) to demonstrate how ROIs can augment statistical power. We first simulated millions of smooth, random 1D datasets to validate theoretical predictions of the 0D, 1D and ROI approaches and to emphasize how ROIs provide a continuous bridge between 0D and 1D results. We then analyzed a variety of public datasets to demonstrate potential effects of ROIs on biomechanical conclusions. Results showed, first, that a priori ROI particulars can qualitatively affect the biomechanical conclusions that emerge from analyses and, second, that ROIs derived from exploratory/pilot analyses can detect smaller biomechanical effects than are detectable using full 1D methods. We recommend regarding ROIs, like data filtering particulars and Type I error rate, as parameters which can affect hypothesis testing results, and thus as sensitivity analysis tools to ensure arbitrary decisions do not influence scientific interpretations. Last, we describe open-source Python and MATLAB implementations of 1D ROI analysis for arbitrary experimental designs ranging from one-sample t tests to MANOVA.
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A comparison of several barefoot inspired footwear models in relation to barefoot and conventional running footwear
Article
Full-text available
  • Jan 2013
This study examined differences in kinetics and kinematics between barefoot and shod running, as well as between several barefoot inspired footwear models. Fifteen participants ran at 4.0 m/s ±5% in each footwear condition. Lower extremity kinematics in the sagittal, coronal and transverse planes were measured using an eight camera motion analysis system alongside ground reaction force parameters. Impact parameters and joint kinematics were subsequently compared using repeated measures ANOVAs. The kinetic analysis revealed that, compared to the conventional footwear, impact parameters were significantly greater in the barefoot and more minimal in barefoot inspired footwear. Running barefoot and in the minimal barefoot inspired footwear was associated with increases in flexion parameters of the knee and ankle at footstrike in relation to the conventional footwear. Finally, the results indicated that the barefoot and minimal barefoot inspired footwear were associated with greater peak eversion magnitude when compared to the conventional footwear. This study suggests that in barefoot and more minimalist barefoot inspired footwear running is associated with impact kinetics and rearfoot eversion parameters, previously linked to an increased risk of overuse injury, when compared to conventional shod running.
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Vector field statistical analysis of kinematic and force trajectories
Article
Full-text available
  • Sep 2013
  • J BIOMECH
When investigating the dynamics of three-dimensional multi-body biomechanical systems it is often difficult to derive spatiotemporally directed predictions regarding experimentally induced effects. A paradigm of ‘non-directed’ hypothesis testing has emerged in the literature as a result. Non-directed analyses typically consist of ad hoc scalar extraction, an approach which substantially simplifies the original, highly multivariate datasets (many time points, many vector components). This paper describes a commensurately multivariate method as an alternative to scalar extraction. The method, called ‘statistical parametric mapping’ (SPM), uses random field theory to objectively identify field regions which co-vary significantly with the experimental design. We compared SPM to scalar extraction by re-analyzing three publicly available datasets: 3D knee kinematics, a ten-muscle force system, and 3D ground reaction forces. Scalar extraction was found to bias the analyses of all three datasets by failing to consider sufficient portions of the dataset, and/or by failing to consider covariance amongst vector components. SPM overcame both problems by conducting hypothesis testing at the (massively multivariate) vector trajectory level, with random field corrections simultaneously accounting for temporal correlation and vector covariance. While SPM has been widely demonstrated to be effective for analyzing 3D scalar fields, the current results are the first to demonstrate its effectiveness for 1D vector field analysis. It was concluded that SPM offers a generalized, statistically comprehensive solution to scalar extraction’s over-simplification of vector trajectories, thereby making it useful for objectively guiding analyses of complex biomechanical systems.
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The Influence of Minimalist and Maximalist Footwear on Patellofemoral Kinetics During Running
Article
  • Mar 2016
The current study aimed to comparatively examine the effects of minimalist, maximalist and conventional footwear on the loads experienced by the patellofemoral joint during running. Twenty male participants ran over a force platform at 4.0 m.s-1. Lower limb kinematics were collected using an 8 camera motion capture system allowing patellofemoral kinetics to be quantified using a musculoskeletal modelling approach. Differences in patellofemoral kinetic parameters were examined using one-way repeated measures ANOVA. The results showed the peak patellofemoral force and pressure were significantly larger in conventional (4.70 ± 0.91 BW & 13.34 ± 2.43 MPa) and maximalist (4.74 ± 0.88 BW & 13.59 ± 2.63 MPa) compared to minimalist footwear (3.87 ± 1.00 BW & 11.59 ± 2.63 MPa). It was also revealed that patellofemoral force per mile was significantly larger in conventional (246.81 ± 53.21 BW) and maximalist (251.94 ± 59.17 BW) as compared to minimalist (227.77 ± 58.60 BW) footwear. As excessive loading of the patellofemoral joint has been associated with the aetiology of patellofemoral pain symptoms, the current investigation indicates that minimalist footwear may be able reduce runners susceptibility to patellofemoral disorders.
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The Relationship between Knee Joint Loading Rate During Walking and Degenerative Changes on Magnetic Resonance Imaging
Article
  • Apr 2014
While animal study and cadaveric study have demonstrated an association between knee joint loading rate and joint degeneration, the relationship between knee joint loading rate during walking and osteoarthritis has not yet been sufficiently studied in humans. Twenty-eight participants (14 transfemoral amputees and 14 age and body mass matched controls) underwent knee MRI with subsequent assessment using the semiquantitative Whole-Organ Magnetic Resonance Image Score. Each subject also underwent gait analysis in order to determine knee adduction moment loading rate, peak, and impulse and an exploratory measure, knee adduction moment rate∗magnitude. Significant correlations were found between medial tibiofemoral joint degeneration and knee adduction moment peak (slope=0.42 [SE 0.20]; P=.037), loading rate (slope=12.3 [SE 3.2]; P=.0004), and rate∗magnitude (slope=437 [SE 100]; P<.0001). These relationships continued to be significant after adjusting for body mass or subject type. The relationship between medial knee semiquantitative MRI score and knee adduction moment loading rate and rate∗magnitude continued to be significant even after adjusting for peak moment (P<.0001), however, the relationship between medial knee semiquantitative MRI score and peak moment was no longer significant after adjusting for either loading rate or rate∗magnitude (P>.2 in both cases). This study suggests an independent relationship between knee adduction moment loading rate and medial tibiofemoral joint degeneration. Our results support the hypothesis that rate of loading, represented by the knee adduction moment loading rate, is strongly associated with medial tibiofemoral joint degeneration independent of knee adduction moment peak and impulse.
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Effects of barefoot and barefoot inspired footwear on knee and ankle loading during running
Article
  • Apr 2014
  • CLIN BIOMECH
Background Recreational runners frequently suffer from chronic pathologies. The knee and ankle have been highlighted as common injury sites. Barefoot and barefoot inspired footwear have been cited as treatment modalities for running injuries as opposed to more conventional running shoes. This investigation examined knee and ankle loading in barefoot and barefoot inspired footwear in relation to conventional running shoes. Method Thirty recreational male runners underwent 3D running analysis at 4.0 m.s- 1. Joint moments, patellofemoral contact force and pressure and Achilles tendon forces were compared between footwear. Findings At the knee the results show that barefoot and barefoot inspired footwear were associated with significant reductions in patellofemoral kinetic parameters. The ankle kinetics indicate that barefoot and barefoot inspired footwear were associated with significant increases in in Achilles tendon force compared to conventional shoes. Interpretation Barefoot and barefoot inspired footwear may serve to reduce the incidence of knee injuries in runners although corresponding increases in Achilles tendon loading may induce an injury risk at this tendon.
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Take your shoes off to reduce patellofemoral joint stress during running
Article
  • Jul 2013
  • BRIT J SPORT MED
Elevated patellofemoral joint stress is thought to contribute to the development and progression of patellofemoral pain syndrome. The purpose of this study was to determine if running barefoot decreases patellofemoral joint stress in comparison to shod running. Lower extremity kinematics and ground reaction force data were collected from 22 trained runners during overground running while barefoot and in a neutral running shoe. The kinematic and kinetic data were used as input variables into a previously described mathematical model to determine patellofemoral joint stress. Knee flexion angle, net knee extension moment and the model outputs of contact area, patellofemoral joint reaction force and patellofemoral joint stress were plotted over the stance phase of the gait cycle and peak values compared using paired t tests and standardised mean differences calculated. Running barefoot decreased peak patellofemoral joint stress by 12% (p=0.000) in comparison to shod running. The reduction in patellofemoral joint stress was a result of reduced patellofemoral joint reaction forces (12%, p=0.000) while running barefoot. Elevated patellofemoral joint stress during shod running might contribute to patellofemoral pain. Running barefoot decreases patellofemoral joint stress.
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Patterns of Compartment Involvement in Tibiofemoral Osteoarthritis in Men and Women and in Whites and African Americans
Article
  • Jun 2012
We conducted a cross-sectional study to describe the prevalence of tibiofemoral joint space narrowing (JSN) in medial and lateral compartments and assess whether it differs by sex and ethnic groups, and, if it does, to what extent such a difference is accounted for by knee malalignment. The Multicenter Osteoarthritis Study is an observational study of persons ages 50-79 years with either symptomatic knee osteoarthritis or high risk of disease. Knee radiographs were assessed for JSN in each tibiofemoral compartment. Mechanical axis angle was measured using full-extremity films. We compared the proportion of knees with medial compartment JSN and with lateral JSN between men and women, as well as between whites and African Americans, using a logistic regression model adjusting for covariates (race or sex and body mass index, age, education, and clinic site). We used generalized estimating equations to account for correlation between 2 knees within a person. Of 5,202 knees (2,652 subjects), 1,532 (29.5%) had medial JSN and 427 (8.2%) had lateral JSN. Lateral JSN was more prevalent in the knees of women than in men (odds ratio [OR] 1.9, 95% confidence interval [95% CI] 1.5-2.4) and was also higher in the knees of African Americans than in whites (OR 2.4, 95% CI 1.7-3.3). Further adjustment for malalignment attenuated the OR for sex but not the OR for race. Women and African Americans are more likely to have lateral JSN than men and whites, respectively. Valgus malalignment may contribute to the higher prevalence in women.
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