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Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
1
Can we modify maximal speed running posture?
Implications for performance and hamstring injuries management
Jurdan MENDIGUCHIA1, Adrian CASTAÑO-ZAMBUDIO2, Pedro JIMENEZ-REYES2, Jean–Benoît MORIN3, Pascal EDOUARD3,4,5, Filipe
CONCEIÇÃO6,7, Jonas DODOO8, Steffi L. COLYER9,10
1 Department of Physical Therapy, ZENTRUM Rehab and Performance Center, Barañain, Spain
2 Centre for Sport Studies, Rey Juan Carlos University, Madrid, Spain
3 Inter
-
university Laboratory of Human Movement Biology (LIBM EA 7424), University of Lyon, University Jean Monnet, F-42023. Saint Etienne, France
4 Department of Clinical and Exercise Physiology, Sports Medicine Unity, University Hospital of Saint-Etienne, Faculty of medicine, Saint-Etienne, France
5 Medical Commission, French Athletics Federation (FFA), Paris France
6 Center of Research, Education, Innovation and Intervention in Sport, Faculty of Sports, University of Porto, Portugal
7 LABIOMEP - Porto Biomechanics Laboratory, University of Porto, Portugal
8 High Performance coaching and conditioning, Speedworks training. Loughborough, Leicestershire. England
9 Department for Health, University of Bath, Bath, UK.
10 CAMERA - Centre for the Analysis of Motion, Entertainment Research and Applications, University of Bath, Bath, UK.
Correspondence: Jurdan Mendiguchia, Department of Physical Therapy, ZENTRUM Rehab and Performance center, Calle B Nave 23 (Polígono
Barañain) 31010 Barañain, Spain - Tel: 34622822253 - Email: jurdan24@hotmail.com
This article is an accepted version for authors’ homepage of this work published in the
International Journal of Sports Physiology and Performance
ABSTRACT
Purpose: Sprint kinematics have been linked to hamstring injury and performance. This study aimed to examine if a
specific 6-week multimodal intervention, combining lumbopelvic control and running technique exercises, induced
changes in pelvis and lower limb kinematics at maximal speed and improved sprint performance.
Methods: Healthy amateur athletes were assigned to control (CG) or intervention group (IG). A sprint test with three-
dimensional kinematic measurements was performed before (PRE) and after (POST) 6 weeks of training. IG program
included 3 weekly sessions integrating coaching, strength and conditioning, and physical therapy approaches (e.g.
manual therapy, mobility, lumbopelvic control, strength and sprint “front-side mechanics” oriented drills).
Results: Analyses of variance showed no between-group differences at PRE. At POST, intra-group analyses showed
PRE-POST differences for the pelvic (sagittal and frontal planes) and thigh kinematics and improved sprint
performance (split times) for the IG only. Specifically, IG showed (i) a lower anterior pelvic tilt (APT) during the late
swing phase, (ii) greater pelvic obliquity on the free-leg side during the early swing phase, (iii) higher vertical position
of the front-leg knee, (iv) an increase in thigh angular velocity and thigh retraction velocity, (v) lower between-knees
distance at initial contact, and (vi) a shorter ground contact duration. Inter-group analysis revealed disparate effects
(possibly to very likely) in the most relevant variables investigated.
Conclusion: The 6-week multimodal training program induced clear pelvic and lower limb kinematic changes during
maximal speed sprinting. These alterations may collectively be associated with reduced risk of muscle strain and were
concomitant with significant sprint performance improvement.
KEYWORDS: Pelvic tilt; sprint performance; sprint kinematics; hamstring strain; sprint mechanics; front-side mechanics
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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1. Introduction
Hamstring strain injuries (HSI) remain highly
prevalent and represent a significant burden in
sports involving high-speed running1–4. Despite
eccentric focused strength training having been
consistently proposed as a successful prevention
method, HSI rates have not improved over the
last 40 years3,4. Contrary to what has been done
in other pathologies such as anterior cruciate
ligament5 or groin pain6, no studies have been
published in which the main injury mechanism
has been biomechanically corrected. Thus, there
is a need to explore variables other than
eccentric strength, including factors such as
sprinting mechanics that can potentially
influence the mechanism of injury.
Anterior pelvic tilt (APT) have been reported to be
closely related to the moments where the
hamstring muscle-tendon tissues face the
highest mechanical strain during sprinting7.
Theoretically, a greater APT would superiorly
translate the ischial tuberosity resulting in a
greater active lengthening and passive tension
demand of the posterior thigh musculature due
to a greater moment arm derived from the
relative hip flexion generated8. The
aforementioned arguments may explain the
association found between APT and HSI risk in
different prospective studies8,9. Assuming that
during maximal speed sprinting the biceps
femoris faces a greater elongation at the
proximal level10 , the level of strain experienced
may be directly influenced by the APT
magnitude, among other factors. Thus, it seems
logical to expect that anatomically, a decrease in
APT would reduce the tensile strength of the
proximal region of the most injured muscle (i.e.
BF) during high-speed running (HSR).
Recently, we showed a change in pelvic
kinematics (i.e. APT decrease) during walking
after 6 weeks of a multimodal training
intervention (manual therapy, mobility,
lumbopelvic control and strength) specifically
designed to correct and decrease APT and
associated lumbar lordosis11. However, it is
necessary to test whether this program would be
efficient when transferred to sprint-specific APT,
since during sprinting, similar hip extension but
greater pelvic anteversion and lumbar lordosis
are observed compared to walking12.
A widely accepted technical model of sprinting,
known as “front-side mechanics” describes how
specific posture or kinematics anterior to the
center of mass are associated with better sprint
performance13. Specifically, front-side
mechanics seeks to maximize leg motions
occurring in front of the vertical torso line while
minimizing actions occurring behind that line
throughout the sprint cycle 13. With specific focus
on maximum speed sprinting, this technical
model is characterized by maintaining an
upright trunk and a neutral pelvic position that
allows reaching a higher knee lift position
during the swing that would allow a subsequent
active leg motion to “punch” the swing leg into
the ground as well as a reduced touchdown
distance (TDd), resulting in lower braking
antero-posterior and higher vertical components
of the ground reaction forces (GRF)13–15. This
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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would allow higher overall stiffness and reduced
stance duration, which have been associated
with greater maximal sprinting speeds15.
However, this technical model and
accompanying coaching emphasis on front-side
mechanics have been primarily based on
descriptive comparisons of elite and sub-elite
athlete’s kinematics13 . To our knowledge, no
scientific evidence has supported the possibility
of altering sprint kinematics, after a specifically
designed training program aimed at improving
front-side mechanics, pelvic and trunk position
and in turn maximal sprint speed.
Therefore, the aim of the present study was to
examine if a specific 6-week multimodal
intervention combined with an on-field running
technique program induced changes in pelvis
and lower limb kinematics at maximal speed.
Based on our recent study showing changes in
APT during gait locomotion11, we hypothesized
that the multimodal training program
(lumbopelvic control exercises + sprint
technique training) proposed in this pilot study
would induce a decrease in APT together with
changes in other biomechanical variables
during the maximum running speed phase of
the sprint towards a more « front-side » oriented
sprint technical model , characterized by: a more
upright trunk position, a higher maximum
vertical knee position during swing phase and
lower between-knees distance with shorter
touchdown distance at initial contact.
2. Methods
Study design
We conducted a prospective comparative trial
with testing sessions separated by a 6-weeks
period comprising an intervention program only
for IG. The present study was approved by the
University of Bath Health Department Ethics
Committee (EP 18/19 027) in agreement with
the Declaration of Helsinki.
Population
Athletes recruitment was made based on the
following inclusion and exclusion criteria:
participants regularly practiced sports involving
sprinting (at least 3 times per week), none of the
athletes had previous experience in the specific
sprint technique training, none of the athletes
had sustained any lower limb or lumbopelvic
injury that might impact on running mechanics
during the 12 weeks prior to the intervention.
Fifteen amateur men athletes (1.79±0.75 m,
77.0±7.6 kg) were recruited and gave their
written informed consent to participate in this
study. Athletes were assigned in a
counterbalanced way according to the initial
sprint performance into two groups: 8 athletes in
the control group (CG; 1.78±0.03 m, 78.9±5.8
kg), and 7 athletes in the intervention group (IG;
1.79±0.07 m, 75.9±9.0 kg).
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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Testing procedures
All tests were conducted at the same time of day,
from 12:00 to 16:00. During both assessments,
subjects were asked to wear a pair of loose shorts
and training shoes. For each session, the warm-
up consisted of 5 minutes of jogging at a self-
selected pace, followed by 5 min of sprint-
specific muscular warm-up dynamic exercises,
two progressive sprints separated by 3 min of
passive rest and two 10-meters flying sprints.
After warm-up, markers were placed for the
three-dimensional kinematics data collection.
Once warm-up and static calibration were
completed, participants were asked to
maximally sprint twice for 35 meters, with a 4-
min recovery between efforts. During these
attempts, the kinematic data of at least one full
stride during the maximum speed phase and
the sprint times were collected. The Qualisys
Track Manager (QTM) software® was used to
record the marker positions during sprint trials,
which was used alongside a single-beam timing
system (Brower timing, Draper, UT, USA).
Photoelectric cell gates were placed at 0, 5, 10,
15, 20, 25 and 35 meters in order to assess
maximal running speed capabilities. See
Supplementary File 1 for details.
Equipment and data acquisition
Three-dimensional kinematics were recorded
using 15 optoelectronic motion analysis
cameras (250 Hz, Oqus, Qualisys AB, Sweden)
with the sample frequency set at 200 Hz. The
cameras were strategically placed on tripods of
different heights between meters 24 and 36 of
the indoor athletics track. An overview of the
described setup can be found in supplemental
file 1. Prior to data collection, the capture
volume of approximately 10×1.1×1.5 m was
calibrated according to manufacturer’s
guidelines. Twenty-four markers were placed
bilaterally on the following lower-limb
landmarks: posterior-superior iliac spine (PSIS),
anterior-superior iliac spine (ASIS), greater
trochanter, medial and lateral femoral condyles,
medial and lateral malleoli, heel, first and fifth
metatarsophalangeal joints (MTP1) and (MTP5)
and the hallux. Additionally, rigid clusters of four
markers were attached to the thigh and shank
segments.
A static calibration trial was used to allow a
kinematic model of each athlete to be
constructed. Subsequently, the medial femoral
condyle, medial malleolus and greater
trochanter markers were removed for the
dynamic trials.
Data processing
Following labelling and gap filling of
trajectories (Qualysis Track Manager v2019.3,
Qualysis, Gothenburg, Sweden) data were
exported to Visual 3D (v6, C-Motion Inc,
Germantown, USA) where raw trajectories were
low-pass filtered (Butterworth 2nd order, cut-off
12 Hz derived through residual analysis). Three-
dimensional lower-limb joint angles (hip, knee
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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and ankle) of the ipsi- and contralateral limb
were computed as the orientation of the distal
segment compared to that of the proximal
segment using a X-Y-Z Cardan sequence.
Similarly, segment orientations (pelvis, thigh
and shank) were computed as the orientation of
those segments compared with the global
coordinate system. Derivatives of the filtered
marker positions were computed using a finite
central differences method and touch-down and
toe-off events were computed following the
method described by Handsaker et al.16. Seven
key events were then identified in each stride
collected for every sprinting trial and used in
subsequent statistical analysis: toe-off (TO),
maximal hip extension (MHE), maximal vertical
knee displacement (MVKD), maximal vertical
projection (MVP), maximal hip flexion (MHF),
touchdown (TD) and full support (FS). Each event
was defined according to specific criteria: the
time at which contact with the ground is lost for
the ipsilateral leg (TO); the time for maximum
hip extension for the ipsilateral leg (MHE); time
for maximum hip flexion for swing-leg (MHF);
time at which maximum distance on the vertical
axis is achieved for swing-leg knee (MVKD);
maximum distance on the vertical axis for the
centre of the pelvic segment (MVP), end of aerial
phase (TD) and the time where lateral malleolus
for support-leg is underneath pelvis segment
centre (FS). The maximum instantaneous
horizontal velocity of the pelvis segment was
also extracted as a proxy measure of maximum
center of mass velocity.
Kinematic parameters
During the captured stride cycles, relevant
dependent variables for ipsi- and contralateral
leg were selected for the subsequent analysis
such as joint angles or segments orientations.
Additionally, TDd, defined as the distance
between the vertical projection of the center of
the pelvic segment and the nearest contact zone
at touchdown, distance between knees (DBK) at
touchdown, maximum knee height (MKH) and
ground contact times (GCT) were considered for
the analysis as discrete variables.
Intervention: multimodal training
Athletes in CG were requested not to modify
their established training routines during the
entire 6-week period.
Athletes in IG underwent a multimodal training
program comprising 3 sessions per week
during 6 weeks. The training program included
coaching, strength and conditioning, and
physical therapy components. The full training
program is provided in the supplemental files 2
(written description) and 3 (video overview). IG
athletes were not allowed to continue their
usual training during the intervention.
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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Statistical analysis
Kinematic data waveforms were temporally
normalized across a single stride cycle
(touchdown to touchdown). Statistical
parametric mapping (SPM) 1D open-source
software was then used to evaluate the
influence of a multimodal training approach
using a SPM 1D paired t-test establishing the
critical threshold at α =0.05. If the SPM{t} curve
exceeded this critical threshold when
comparing post assessment data, kinematics
were deemed to be significantly different to the
pre-test at these specific nodes. Data from all
successfully collected strides were used for the
analysis.
To obtain a more general picture of the effects of
the intervention and to minimise possible
distortion caused by temporal normalisation, a
discrete analysis of the kinematic variables was
also performed in JASP (version 0.12.2) for the
key events described above17,18.
Values were reported as mean ± standard
deviation (SD). Statistical significance was
established at the p<0.05 level. Independent-
sample t-tests were conducted to examine inter-
group differences at PRE (before 6-weeks
period) whereas paired-sample t-tests were
used to analyse intra-group changes between
PRE and POST. Effect sizes (ESs) alongside
confidence intervals were calculated using
Cohen’s d standardised differences. Effects were
deemed to be practically meaningful if the 95%
confidence interval did not cross zero (in either
direction). Only results with ES≥0.8, this value
being set as large, are highlighted in
Supplemental file 4 and then detailed in
Supplemental file 5.
The smallest worthwhile change (SWC) [0.2
multiplied by the between-subject standard
deviation], based on Cohen ES principle19 was
used to calculate inter-group differences based
on the difference experienced by both groups in
the most representative variables of running
kinematics. Quantitative of the actual effect
were assessed qualitatively as follows: 0.5%,
most unlikely; 0.5–5%, very unlikely; 5–25%,
unlikely; 25–75%, possibly; 75–95%, likely; 95–
99%, very likely; and .99%, most likely.
3. Results
Primary outcome: sprint kinematics
No significant differences were found between
groups at PRE when analysing segments and
joints curves by SPM or independent t-test.
Once the 6-weeks period was concluded (at
POST), the intra-group SPM analysis revealed
differences for the pelvic and thigh segments in
the sagittal plane for the IG (Figure 1), while not
for CG. Additional discrete analysis for these
variables revealed a large number of significant
differences regarding the angle of the joints or
the orientation of these segments at the defined
key moments (see Supplemental files 4 and 5
for a detailed analysis). The differences for the
most representative variables are summarized
for better understanding in Table 1 and visually
recreated in Figure 2.
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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Figure 1. Pelvic tilt, pelvic obliquity and thigh orientation in the sagittal plane on SPM Analysis. Dark lines and
shadows refer to mean and SD PRE values for the intervention group while red lines refer to POST values. Vertical
dashed lines represent toe off moments for both ipsi and contralateral limbs (black and red, respectively). Horizontal
red dashed lines represent the statistical significance threshold between both moments.
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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Table 1. Intragroup differences for the most representative variables of running kinematics investigated.
Data are expressed as mean and standard deviation (in brackets). Grey tones indicate ES values greater than 0.8. *: p<0.05; **: p<0.01
Individual responses should be interpreted as absolute increase/decrease (black and grey, respectively).
MVP: Maximal vertical projection; Late Swing APT: Mean APT across 80-95% stride; TD: Touchdown; MKVD: Maximal knee vertical displacement;
DBK: Distance between knees
Figure 2. Visual representation of the identified changes between PRE and POST for the intervention group.
MVP: Maximal vertical; MKVD: Maximal knee vertical displacement
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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Furthermore, only the IG significantly decreased
the DBK -indicator of the amount of “leg
recovery”- at touchdown [PRE: 0.28 ±0.06 m to
POST: 0.16 ±0.03m; ES: -2.02 (LL: -3.34; UL: -
0.66); p:0.002], significantly increased the
maximum knee height reached [PRE: 0.68
±0.06 m to POST: 0.77 ±0.08 m; ES: 3.05 (LL:
1.20; UL: 4.68); p<0.001], average thigh
angular velocity during the entire gait cycle
[PRE: 388.7 ±17.6 °⸱s-1 to POST: 411.7 ±9.2 °⸱s-
1; ES: 1.13 (LL: 0.14; UL: 2.08); p:0.029],
average thigh angular retraction velocity (PRE:
301.8 ±52.4 °⸱s-1 to POST: 354.9 ±50.3 °⸱s-1;
ES: 1.44 (LL: 0.33; UL: 2.51); p:0.009] and
significantly reduced ground contact time
(0.109 ±0.008 s to 0.102 ±0.008 s; ES: -0.96
(LL: -1.85; UL: -0.03); p<0.05).
Kinematic inter-group differences for the most
relevant kinematic variables can be observed in
Figure 3.
Figure 3. Efficiency of the multimodal program on the Intervention Group (IG) compared to Control Group (CG) over
the most relevant kinematic variables investigated (bars indicate uncertainty in the true mean changes with 95%
confidence intervals). Trivial areas were calculated from the smallest worthwhile change (SWC).
DBK: Distance between knees; MVP: Maximal vertical projection; APT: Anterior Pelvic Tilt; Late Swing APT: Mean APT
across 80-95% stride; TD: Touchdown; MKVD: Maximal knee vertical displacement
Secondary outcome: sprint performance
No significant differences between IG and CG
were found at PRE for any of the split times
analysed. The CG showed no significant
differences for any of the split times between
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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PRE and POST, whereas statistically significant
decreases (p<0.05) were found for 0-5
(p:0.013), 5-10 (p:0.015), 10-15 (p:0.049), 25-
35 (p:0.015), 0-10 (p:0.011), 0-20 (p:0.023)
and 0-35 (p:0.029) split times in the IG group
(Table 2).
Table 2. Changes in sprint performance between PRE and POST.
Intra-group significant differences from PRE to POST training: *: p<0.05; **: p<0.01
4. Discussion
The main findings of the present study validate
our initial hypothesis and were, firstly, that 6-
week multimodal intervention combining
lumbopelvic control exercises with a running
technique program induced significant changes
in sagittal and frontal plane kinematics of the
pelvis at maximal speed. This resulted in a lower
APT during the late swing phase and a higher
pelvic obliquity on the free leg side during the
early swing phase. Similarly, the kinematics of
the lower extremities were also modified
according to the front-side mechanics
principles, resulting in an increase in the
maximum height reached by the knee, followed
by an increase in the thigh angular retraction
velocity, as well as a decrease in the DBK at
initial contact, along with a shorter landing
distance and contact time. Finally, all these
modifications were followed by a change in
sprint performance, reflected in the significant
decrease in the 0-5, 5-10, 10-15, 25-35m split
times and 0-20m and 0-35m cumulative split
times recorded during the maximum sprint test,
compared with CG during the same period of
time.
This study is, to our knowledge, the first
showing a change in pelvic kinematics after a
multicomponent training intervention
specifically directed to correct and decrease APT
at maximum running speed.
Interest of the present findings for HSI risk
management
One of the reasons why the prevalence of biceps
femoris (BF) injury could be higher would be
related, among other factors, to a greater non
uniform elongation peak of the proximal BF
during the late swing phase of maximal speed
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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sprinting10. Assuming strain as the major
determinant of tissue failure and considering
that the ipsilateral elongation peak of the BF
coincides with contralateral iliacus maximum
stretch and the second peak pelvis anterior tilt
all together during late swing phase20,21, it
seems logical to expect that a posterior tilt of the
pelvis, as found in this study, would reduce the
suggested BF musculotendon stretch and
eccentric demand, probably specifically at its
proximal region. The possible association
between the pelvic joint movements and the BF
behavior could have an anatomical origin since
this muscle is the only hamstring muscle
anatomically linked to the ischial tuberosity with
connections to the sacrotuberous ligament22,
structure whose role has been proven as
fundamental in the stabilization of the pelvis23.
The balance between the musculature
functionally favoring APT iliopsoas, erector
spinae and the musculature counteracting it,
such as the abdominals and gluteus during
swing phase of HSR, seems to play a key role on
BF strain and may explain the association found
with HSI in prospective studies21,24.
However, given the intervention design of this
study, it is impossible to know whether the
decrease in APT is caused by the multimodal
training intervention or is a consequence of the
process of the individual's ability to acquire the
desired sprint motor skills as a function of the
practice related to the sprint technique
program. It cannot be ruled out that certain
parts of the program have advantageous and
additive reciprocal effects, as it stands to reason
that sprinting ability cannot be improved
without a good underlying training and
performance structure. In summary, a
combined intervention of lumbopelvic control
exercises mixed with a running technique
program induced lower APT and can be
considered one more tool within a multifactorial
rehabilitation or prevention approach,
especially in those athletes that show excessive
APT and may be more susceptible to HSI.
Lower limb kinematics and performance
relationship
Based on the reported results, it seems justified
to assume that the observed lower limb
kinematic changes would place the IG
somewhere close to the targeted front-side
mechanics technical model that is theoretically
associated with better maximal-speed sprint
performance according to literature13–15.
Interestingly and in contrast to the significant
decrease in the sagittal plane of the pelvis
motion shown in the late swing phase (Figure 1
and 2), we observed a significant overall
increase in the frontal plane motion during
early swing phase (Figure 1) of maximal
running speed. It has been suggested that a
greater pelvis obliquity during push-off25 as
observed in the present study is associated with
greater vertical GRF, which is a key determinant
factor to reach and maintain high running
speed25,26. Although GRFs were not recorded in
this study, the changes recorded in the IG group
could explain the performance improvement
observed on the basis of the kinematic-kinetic
relationship described in the literature. The new
segmental alignment is recognised by a
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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reduced pelvic anteversion throughout the
stride (-5º for pelvic tilt along the stride) and a
faster and more active recovery of the ipsilateral
leg. A more upright position combined with a
modified free leg offset shifts the back to front-
side mechanics in this new arrangement. As
sprinting entails a sequence of segments
positions/movements during which each
position/movement results from the previous
one and in turn influences the following one,
the achievement of a higher knee position
(+0.09m) offers athletes a greater potential to
accelerate the leg towards the ground (leg
retraction) given the extended range of
motion13–15. The enhanced impact-limb
deceleration mechanism in the IG is supported
by a significantly higher thigh angular retraction
velocity (+17.5% ), providing a biomechanical
solution to "attack the ground" vertically and
overcome the mechanical limitation of
maximum sprinting speed imposed by the short
stance duration requirement13–15,26. However,
an active recovery of the trailing leg (scissors like
action) is required to achieve high vertical
velocities on landing as part of the deceleration
mechanism of the impact limb13. This ability is
identified within the front-side mechanism
model based on DBK at touchdown and is
considered an indicator of "leg switch
efficiency"13. According to our results, the IG
presented significantly decreased distance at
this point (43% closer on average).
Concomitantly, the fact that IG showed a higher
mean thigh angular velocity supports and
validate the data provided by knee separation
and confirms that, as recently demonstrated,
more vigorous scissor like action of the thighs
(flexion-extension reversals) are necessary to
improve sprint performance27.
Parallel to an improvement in “leg switch
efficiency”, the IG showed significantly higher
thigh angular retraction velocities as well as a
shorter but not significant TDd (5%) and ground
contact times (6%) (Figure 2) that could be
related to an overall more efficient impact
deceleration mechanism resulting in a greater
vertical GRF component. Recently, Clark et al.27
demonstrated that both mean thigh angular
velocity and retraction velocity had a strong
positive linear relationship with the vertical
velocity of the lower limb at the instant of
touchdown. This factor, coupled with rigid
ground contact and rapid deceleration of the
lower limb upon ground contact appears to be
decisive for the development of the specific
vertical forces needed to support faster
speeds14,15,27.
Translating the results of this study (~ one tenth
of a second decrease on 0-20m and 0-30m) into
practice, and taking into account that, a 30-50
cm difference (~0.04-0.06 s over 20m) is
probably enough in order to be decisive in one-
on-one duels in football indicating the
suitability of this type of intervention on team
sports settings28. In summary, all the training-
induced kinematic changes observed within the
intervention group collectively align with the
different studies suggesting that forces are
generated proximally and must be effectively
transmitted distally via stiff lower limb during
HSR29.
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
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However, our results show that changes in
maximal-speed sprint kinematics are possible
with training, but they do not clearly prove that
these are directly related to the performance
improvement observed. This association should
be taken with caution since (i) studies
advocating the front-side mechanics concept
use mere cross-sectional kinematic comparisons
between sprinters of different level of
performance13 and (ii) other studies did not
confirm this association30. The fact that the
subjects of the present study were physically
active and used to sprint but not elite could bias
this association: it cannot be ruled out that
sprint training alone could have induced
performance improvements. Finally, the study
was performed only on males and further
research is necessary in order to ascertain
whether similar changes are possible in female
subjects.
Practical applications
A 6-week intervention program, designed with
the goal to preserve an optimal state of the
structures (lumbopelvic multimodal program)
that would allow a correct execution of the field
running technique program, showed a decrease
in the anterior pelvic tilt during late swing phase
of sprinting (potentially decreasing hamstring
strain) as well as lower limb kinematic changes
associated to performance improvement.
Therefore, altering body posture during
sprinting could be one more strategy to use, if
indicated, to those commonly used within a
multifactorial and individualized hamstring
prevention approach and performance
enhancement.
5. Conclusion
This study showed for the first time that a
multimodal intervention combining
lumbopelvic control exercises with a running
technique program was able to modify the
kinematics (pelvis and lower limbs) of maximal
speed sprinting. These alterations may
collectively be associated with reduced tissue
strain (injury risk) of the hamstrings and were
concomitant with significant sprint performance
improvement.
Acknowledgements
This study was made possible by technical support from the Department for Health, University of Bath.
The authors are grateful to Andrea Astrella from Sports Biomechanical Engineering for his illustrations
and Victor Cuadrado for his support. We would like to thank the participants of this study for their
cooperation and effort.
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
14
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SUPPLEMENTARY FILE 1:
Schematic view of the experimental setting.
SUPPLEMENTARY FILE 2:
Multimodal intervention program
SUPPLEMENTARY FILE 3:
Link to video: https://www.youtube.com/watch?v=s1dnt7NQ8PU
Mendiguchia et al. 2021 – Int J Sport Physiol Perf – Changing maximal speed running posture
16
SUPPLEMENTARY FILE 4: Summary for the intra-group differences analysis. Data are expressed as mean and standard
deviation (in brackets). Grey tones indicate ES values greater than 0.8.
SUPPLEMENTARY FILE 5: Summary of the magnitude and orientation of the significant differences reported for the
intra-group analysis
TOE-OFF MHE MHF MVKD MV P TOUCHDOWN FULL SUPPORT
Pelvic Rotation Pelvic Tilt Pelvic Tilt Pelvic Rotation
p: 0.01; Δ: -9.2%; ES: -1 .24
(LL: -2.16; UL: -0.28)
p: 0.04; Δ: -17.0%; ES : 0.86
(LL: 0.02; UL: 1.66)
p: 0.06; Δ: -16.7%; ES : 0.81
(LL: 0.02; UL: 1.59)
p: 0.06; Δ: -50.4%; ES : -0.81
(LL: -1.60; UL: 0.02)
Pelvic Obliquity Pelvic Obliquity
p: 0.03; Δ: 55.0%; ES: - 0.99
(LL: -1.83; UL: -0.11)
p: 0.03; Δ: 52.3%; ES: - 0.97
(LL: -1.80; UL: -0.10)
Ipsilateral Hip Contralateral Hip Contralateral Hip
p: 0.05; Δ: 19.2%; ES: 0 .86
(LL: 0.02; UL: 1.66)
p: 0.03; Δ: -6.4%; ES: 0 .94 (LL:
0.08; UL: 1.77)
p: 0.03; Δ: -6.6%; ES: 0 .97 (LL:
0.10; UL: 1.81)
Contralateral Knee
p: 0.04; Δ: -8.5%; ES: 0 .90 (LL:
0.05; UL: 1.72)
Pelvic Tilt Pelvic Obliquity Pelvic Tilt Pelvic Tilt Pelvic Tilt Pelvic Tilt
p: 0.02; Δ: -31.9%; ES : 1.22
(LL: 0.19; UL: 2.20)
p: 0.07; Δ: 110.2%; E S: 0.81
(LL: 0.73; UL: 1.66)
p: 0.06; Δ: -31.7%; ES : 0.85
(LL: -0.05; UL: 1.70)
p: 0.06; Δ: -38.4%; ES : 0.89
(LL: -0.02; UL: 1.76)
p: 0.05; Δ: -32.4%; ES : 0.91
(LL: -0.01; UL: 1.78)
p: 0.07; Δ: -34.5%; ES : 0.81
(LL: -0.07; UL: 1.66)
Contralateral Knee Ipsilateral Ankle Ipsilateral Ankle Contralateral Knee Ipsilateral Hip Ipsilateral Hip Ipsilateral Ankle
p: 0.01; Δ: 10.5%; ES: - 2.01
(LL: -3.33; UL: -0.66)
p: 0.04; Δ: -9.4%; ES: 0 .99 (LL:
0.04; UL: 1.88)
p: 0.03; Δ: -15.0%; ES : 1.11
(LL: 0.12; UL: 2.05)
p: 0.03; Δ: 12.3%; ES: - 1.11
(LL: -2.05; UL: -0.12)
p: 0.01; Δ: 101.4%; E S: -1.43
(LL: -2.49; UL: -0.32)
p: 0.05; Δ: -15.4%; ES : 0.95
(LL: 0.01; UL: 1.83)
p: 0.05; Δ: -8.8%; ES: 0 .93 (LL:
0.01; UL: 1.81)
Ipsilateral Ankle Contralateral Hip Contralateral Ankle Ipsilateral Knee
p: 0.04; Δ: -6.3%; ES: 1 .01 (LL:
0.05; UL: 1.92)
p: 0.03; Δ: 12.7%; ES: - 1.11
(LL: -2.05; UL: -0.12)
p: 0.04; Δ: -12.4%; ES : 1.02
(LL: 0.06; UL: 1.93)
p: 0.01; Δ: 22.9%; ES: - 1.78
(LL: -2.99; UL: -0.53)
Contralateral Knee
p: 0.01; Δ: 37.0%; ES: - 3.47
(LL: -5.51; UL: -1.41)
Ipsilateral Thigh Ips ilateralThigh Ipsilateral Thigh Ipsilateral Thigh Ipsilateral Thigh Contralateral Thigh Contralateral Thigh
p: 0.07; Δ: -21.4%; ES : 0.81
(LL: -0.08; UL: 1.65)
p: 0.04; Δ: -11.2%; ES : 0.97
(LL: 0.03; UL: 1.86)
p: 0.01; Δ: 14.6%; ES: 1 .51
(LL: 0.37; UL: 2.60)
p: 0.03; Δ: -18.7%; ES : 1.05
(LL: 0.08; UL: 1.96)
p: 0.01; Δ: -56.0%; ES : 1.39
(LL: 0.30; UL: 2.43)
p: 0.03; Δ: -152.7%; E S: 1.07
(LL: 0.1; UL: 2.00)
p: 0.01; Δ: 90.1%; ES: 1 .46
(LL: 0.34; UL: 2.53)
Contralateral Thigh Contralateral Thigh Contralateral Thigh Ipsilateral Shank Ipsilateral Shank Contralateral Shank
p: 0.01; Δ: 20.6%; ES: 1 .50
(LL: 0.38; UL: 2.63)
p: 0.01; Δ: 25.7%; ES: 3 .01
(LL: 1.19; UL: 4.82)
p: 0.02; Δ: 21.3%; ES: 1 .22
(LL: 0.19; UL: 2.20)
p: 0.04; Δ: -10.4%; ES : 0.98
(LL: 0.04; UL: 1.87)
p: 0.08; Δ: -111.9%; E S: -0.8
(LL: -1.64; UL: 0.08)
p: 0.05; Δ: -9.0%; ES: 0 .95 (LL:
0.02; UL: 1.83)
Ipsilateral Shank Contralateral Thigh
p: 0.59; Δ: 11.1%; ES: 0 .88
(LL: 0.88; UL: -0.03)
p: 0.01; Δ: 18.1%; ES: 2 .25
(LL: 0.79; UL: 3.69)
Contralateral Shank
p: 0.02; Δ: 202.1%; E S: -2.00
(LL: -3.31; UL: -0.65)
JOINTS
INTERVERNTION GROUP
Used acronyms : MHE (Maximal Hip Flexion), MKVD (Maximal Knee Vertical Displacement), MVP (Maximal Vertical Proje ction), MHF (Maximal Hip Flexion), LL (Lower limit), UL (Upper limit)
INTRA-GROUP DIFFERENCE S
CONTROL GROUP
PELVIS
JOINTS
SEGMENTS
PELVIS
SEGMENTS
