Decreased ankle dorsiflexion may [603246]

Decreased ankle dorsiflexion may
increase the risk of Achilles tendinopathy
among 400-m hurdles track -and-field
athletes: A prospective, observational
study .

Final Project

Sousa Aday

Mentor: Joaquim Chaler, PhD

Degree: Physiotherapy

Escola Universitària de la Salut i l’Esport (EUSES)

Barcelona, 8 May 2020

Table of contents
• Hypothesis ………………………………………………………………………… p. 5
• Objectives …………………………………………………………………………. p. 6
• Introduction ……………………………………………………………………….. p. 7
• Study Design ……………………………………………………………………… p. 1 1
• Flow Diagram of the Study Design ………………… …………………………… .. p. 12
• Study Setting/Recruitment ………………………………………………………… p. 12
• Sample Size ……………………………………………………………………….. p. 12
• Eligibility Criteria (Inclusion/Exclusion criteria) …………………………………. p. 13
• Randomization and Blinding ……………………………………………………… p. 13
• Study Procedures/Measurements …………………………………………………. p. 13
• Outcomes …………………………………………………………………………. p. 1 6
• Assessments ……………… ………………………………………………………. p. 17
• Statistical Analysis ……………………………………………………………….. p. 1 7
• Ethics ………………………………………………………………………………. p. 1 7
• Calendar/Planning ………………………………………………………………… p. 1 8
• Limitations ……………………………………………………………………….. p. 1 8
• Role of the Inves tigators ………………………………………………………….. p. 19
• Resources …………………………………………………………………………. p. 19
• References ………………………………………………………………………… p. 2 0
• Annex I: Informed Consent .. ……………………………………………………… p. 2 6

Acknowledgement
First of all, I would like to thank my mentor , Joaquim Chaler (PhD) for his encouragement
and constant support during my final project.
Then, I would like to thank my family for all the support and motivation received since
the very beginning of my studies.

Abstract
Introduction: A limited ankle dorsiflexion range of motion ( DF-ROM ) has been
identified as a risk factor for several musculoskeletal conditions in different sports
disciplines . However, no research has investigated the relationship of a decrease in ankle
dorsiflexion with Achilles tendinopathy incidence in athletics, and s pecifically in the 400 –
m hurdles. Therefore, the purpose of this study is to investigate the relationship between
DF-ROM at the end of the season compared to the DF-ROM at the beginning of the
season and risk of developing A chilles tendinopathy in healthy 400-m hurdles track -and-
field athletes following a whole season.
Methods /Design : The present study is a prospective cohort, multi -centre study, with
assessments at the b eginning and at the end of the season, including a follow -up of
Achilles tendinopathy incidence during the same season (2021/2022). Ankle DF -ROM
and plantar flexor strength will be assessed. Tr aining frequency, number of competitions
and internal load will be collected . The primary outcome will be the difference in DF-
ROM at the end of the season compared to DF -ROM at the beginning of the season . The
secondary outcome will be Achilles tendinopathy incidence during the season .
Discussion: The clinical expected result to find in the present study is that a decrease of
the DF -ROM at the end of the season compared with the DF-ROM at the beginning of
the season increases the risk of developing Achilles tendinopathy in healthy male 400 -m
hurdles track -and-field athletes . In this case, it would be crucial to implement strategies
to increase the DF -ROM and subsequently decrease the risk of developing Achilles
tendinopathy among 400-m hurdles track -and-field athletes.
Keywords: tendinopathy, dorsiflexion , athletics , injury, sport.

5
Hypothesis

Null hypothesis
A decrease of the dorsiflexion ROM at the end of the season compared to the beginning
of the season is not related to the risk of developing Achilles tendinopathy in healthy 400-
m hurdles track -and-field athletes.

Alternative hypothesis
A decrease of the dorsiflexion ROM at the end of the season compared to the beginning
of the season is related to the risk of developing Achilles tendinopathy in healthy 400-m
hurdles track -and-field athletes.

6
Objectives

Primary objective
This protocol for a prospective cohort study aims to evaluate the difference in dorsiflexion
ROM at the end of the season compared to dorsiflexion ROM at the beginning of the
season in healthy 400-m hurdles track -and-field athletes , objectively measured with the
WBLT.

Secondary objective
To identify the relationship between the difference in post -season DF-ROM compared to
pre-season DF-ROM and the incidence of Achilles tendinopathy following a season in
healthy 400-m hurdle s track -and-field athletes .

7
Introduction

Achilles tendinopathy (AT)
Achilles tendinopathy is a common condition among sports activities involving jumps
and sprints ( 1). Specifically, it is the lower limb tendon pathology with more prevalence.
It has a prevalence of 6.2 to 9.5% and an incidence of 9.1% to 10.9% in the athletic
population ( 2). It impacts on the ability to work and be physically active , evoking in a
socio -economic burden ( 3). It leads to pain, reduced tolerance to exercise and a decrease
in function ( 4,5). It is one of the two tendons most regularly affected due to overuse,
together with the patellar tendon ( 6).

AT risk factors
Intrinsic factors, such as age, sex, genetics, pes cavus, tendon vascularity, limited
dorsiflexion range, plantar flexor weakness /decreased strength , lateral ankle instability,
diabetes, excess adiposity, hyperlipidaemia, inflammatory and autoimmune diseas es, and
asymptomatic tendinopathy on imaging are involved in the future development of this
pathology (7 -13). Extrinsic factors, for instance, acute injury, repeated overuse, corticoid
injections and physical deconditioning are also determinant for the dev elopment of
Achilles tendinopathy, as it commonly has a multifactorial cause ( 14,1).
A recent systematic review made by Vlist et al. (2019) suggested new important risk
factors , such as previous history of lower limb tendinopathy or fracture, ofloxacin intake
(type of antibiotic ), increased time between heart transplantation and initiation of
quinolone treatment for infectious disease s, moderate alcohol intake , training during cold
climatic conditions , abnormal gait pattern with diminished forw ard progression of
propulsion, more lateral foot roll -over at the forefoot flat phase , and creatinine clearance
of <60 mL/min in patients with a heart transplant (15).

AT aetiology
The Achilles tendon is relatively thick and strong, in comparison with other tendons of
the body ( 12). Type of high loads that can lead to condition and pain include energy
storage (i.e. jumping and sprinting), friction (repetitive ankle movements) or compression
loads (hill running) ( 3).

8
Depending on the ten don part affected, Achilles tendinopathy can be distinguished as
insertional (tendon insertion onto the calcaneus), midportion (the point between 2 and 7
cm proximal to the insertion) or peritendinous (connective tissue surrounding the tendon)
(16).
Despi te underlying mechanisms of tendinopathy remain not understood, three conceptual
models have been suggested to explain them: tendon cell response, collagen disruption
and inflammation. The current model is that pathology originates from an initial reaction
of the tendon cells to an overload, that concludes in a proteoglycans increase, and a tendon
cell activation and proliferation. It ends in a collagen matrix disruption and an increased
vascularisation ( 17,18).
Cook and Purdam (2009) suggested a model for staging tendon pathologies depending on
the changes and disorganisation structure within the tendon, called “the continuum
model”. It has 3 phases: reactive, disrepair and degenerative tendinopathy ( 4).

AT examination and diagnosis
The diagnosis of thi s pathology in physically active populations is mainly based on a
complete history and physical exam. The main clinical finding is focalised pain in the
Achilles region, aggravated by high loads . Usually, it can also be accompanied by a
decrease in the strength and endurance of the plantar flexors. In the acute phase, an
Achilles tendon rupture should be contemplated. Differential diagnosis, such as calcaneal
bursitis or tibialis posterior tendinopathy, among others, also have to be taken into account
(3).
As there exists a poor correlation between abnormal tendon imaging and pain, it could
help with differential diagnosis, confirming tendon rupture and identifying in which phase
of the “continuum” the tendon is, but it has no function in the diagnosis o r prognosis in
tendon pathology and cannot be applicable as an outcome measure ( 19, 20).

Ankle dorsiflexion (DF)
Ankle dorsiflexion, also known as ankle flexion, or ankle dorsal flexion, is the movement
in which the dorsal aspect of the foot approaches th e anterior aspect of the leg ( 21). It is
also defined as ankle displacement in the sagittal plane (22). An acceptable DF-ROM is

9
crucial to the effective functioning of basic weight -bearing actions, for instance walking
(23), climbing and descending stairs (24), and landing activities ( 25,26).
Landing movements in sporting tasks, nonetheless, exert high requirements on ankle
structures due to the absorption and dissipation of the high ground reaction forces (GRF)
encountered upon ground contact (GC) performed during each landing task ( 25,26).
Landing exercises demand a slowdown of the lower limb momentum, as it acts in a
coordinated multi -joint pattern ( 26-28).
A limited ankle D F-ROM is advised to be a predisposing factor for several injuries,
includi ng patellar ( 29-32) and Achilles tendinopathy ( 33,34), anterior cruciate ligament
(ACL) injury ( 35,36), hamstring strain ( 37-39) and patellofemoral pain syndrome (PFPS)
(40, 41 ) among others, in different sport disciplines. It is also determined to be an
important factor during lower limb rehabilitation ( 42).
Exactly, the smallest significant score to determine impairments in ankle D F-ROM is
>2cm in the Weight -Bearing Lunge Test (WBLT) ( 43). Changes of 1 cm represent 3.6 ș
in the WBLT (44). So, the cut-off score to identify impairments in the D F-ROM is a
decrease of 7.2ș. Furthermore, the cut -off point considered limiting for weight -bearing
DF-ROM is ≤ 44ș (45).

400-m hurdles (400 -mH)
400-m hurdles is a rhythmic sprinting event, like other modal ities of hurdle sprints
(46,47). It is reasonably the most demanding discipline in the sprints and hurdles group
(47-50). It is composed of 10 hurdles of 0,914 m (men) or 0,762 m (women), with a 35
m distance between hurdles. It is crucial to have a long sprint running ability by
accomplishing and sustaining high running speed in between each hurdle ( 51) and
attenuate velocity slowdown during hurdle clearance ( 52). In between the first and third
hurdle, the highest velocity is reached, and then it is diminished gradually ( 53). It is
mostly supplied by the anaerobic glycolytic system ( 54-59).
It is not a jumping event, despite novice athletes tend to jump over the hurdles instead of
running over them in a modified running pattern. Athlete’s centre of mass (CoM) should
be raised only slightly, to be efficient during clearing a hurdle ( 46, 47).

10
Stride pattern should be used, which means using a specific number of strides to the first
hurdle and a defined number of strides between each hurdle ( 46). Lengt hen the sprinting
stride and deviating the minimum as possible from the normal sprinting pattern (400 -m
flat runs) is basic for this sporting discipline. The athlete should have the ability to clear
hurdles with either leg as it is a safe way of changing t he stride pattern during a race due
to external factors (wind, surface, etc.) ( 60). It requires a high level of concentration all
over the competition ( 46, 47).

400-mH biomechanics
The placement of the trail leg foot has to be active during the whole ROM. The athlete
needs to pull back from the hip, with the ankle stable, strong and the foot in dorsiflexion.
This active landing movement with the forefoot is going to reduce the deceleration going
into the hurdle by reducing the last stride ( 50).
To have the most economical body position to attack the hurdle, the athlete should lead
with the knee of the lead leg when going into the hurdle. The hurdler must flex the lower
portion of the leg speedily, at the earliest opportunity after the limb breaks the contact
with the track to accomplish it. The thigh remains above the lower part of the lead leg
until it has reached the apex. Then, knee joint opens, hamstring relaxes and momentum
is transmitted to the lower part of the leg. The knee of the lead leg is not locked, because
it allows a more economic rotation of the thigh of the lead leg ( 48, 50). The lead leg and
the opposing arm should move parallel to help the hurdler keep his or her hips and
shoulders square to the obstacle. It also removes the uppe r limb twisting. The speed of
the lead leg has to go along with that of both arms ( 48,50).
The trail foot takes off the ground and the trail -leg lever shortens to the full by moving
the leg powerfully upward and forward and bending the heel to the buttock s. It diminishes
the compensation of rotation in the other parts of the body and allows the leg to pass over
the obstacle with higher velocity. The foot of the trail leg must never be more elevated
than its knee. The trail leg keeps properly bent until kn ee reaches the front of the body
and it prepares to increase speed downwards to the ground again ( 50).
At touchdown, when the athlete goes over the hurdle, he/she has to minimize shoulders
and arms rotation by directing his/her body forwards. The athlete’s CoM must be exactly
situated over the lead foot. At this moment, the hurdler should try to keep the forward

11
braking as low as possible, crucial to re -establish the running pattern between each hurdle.
The trail leg should be tight until the touchdown and then coming down fast into a
sprinting position. The getaway stride must be powerful and grabbing the ground ( 47, 48,
50).
Limitation of ankle DF -ROM has been identified as a risk factor for several
musculoskeletal conditions in different sports discipline s. However, no research has
investigated the relationship of a decrease in ankle dorsiflexion with Achilles
tendinopathy incidence in athletics, and specifically in the 400 -m hurdles. Therefore, the
purpose of this study is to investigate the relationship between DF-ROM at the end of the
season compared to the DF-ROM at the beginning of the season and the risk of developing
Achilles tendinopathy in healthy 400-m hurdles track -and-field athletes following a
whole season.

Study Design
The present study is a n observational prospective cohort multi -centre study, with
measure ments after two weeks of the beginning of the season (pre -season) and 10 months
later (post -season), with a follow -up of the participants during the 2021/2022 season.
STROBE statement is followed to construct the protocol , according to the study design.
The research is going to start in September 202 1 and is going to finish on July 202 2.

12
Flow Diagram of the Study Design

Figure 1. Flow diagram of the study design .

Study Setting /Recruitment
Participants enrolled in the study will be recruited from several clubs affiliated to the
Catalan Athletics Federation . They will be contacted privately. Measurements will be
taken in 3 track -and-field stadiums from Barcelona: Joan Serrahima , La Mar Bella and
Can Dragó .

Sample Size
Even though no sample calculation is going to be specified in this protocol, is necessary
to emphasize that is important to get as many participants as possible because the more
extensive the sample, the better, as it is a prospective and observational study and it will
allow diminishing the residual error. All 400 -mH athletes affiliated to the Catalan
Athletics Federation will be contacte d. All participants must meet the eligibility criteria
and sign the informed consent before the commencement of the study .

13
Eligibility Criteria

Inclusion criteria
Subjects included in the study must meet the following criteria: (1) Athletes practising
400m hurdles, (2) Aged 18 to 35 years old, (3) Able to come to Barcelona for the
assessments, (4) No prior lower limb tendinopathy or fracture, (5) No prior history of hip,
knee, or ankle surgery.

Exclusion criteria
Subjects will be excluded of the study in any of these scenarios : (1) Relevant lower limb
injuries in the six months previous to testing , (2) Current use of bracing or taping in the
ankle or knee , (3) Use of ofloxacin (antibiotic) , (4) Concomitant serious conditions ,
(5)Not able neither willing to provide written informed consent , (6) No regular training
during the previous six months , (7) Presence of ankle instability.

Randomization and Blinding
Despite any type of blinding cannot be done, health professionals performing the
assessments will not know the objectives of the present study to avoid any type of bias.

Study procedures/ Measurements
Subjects will not receive any kind of myofascial releas e or similar procedures to treat
tight muscles on assessment days. Other treatments provided by the physical therapists
during the season, specifically focused on the gastrocnemius and soleus, will be
considered as normal interventions.
It is important to consider that before each assessment day, subjects will perform a warm –
up. It will consist of three minutes of low -moderate intensity running. Then, each
participant will do five minutes of dynamic stretching. The type exercises and inte nsity
of them will be the same for each athlete. All measurements will begin to be carried out
three minutes after the dynamic warm -up.
All assessments (pre, and post -season) will be taken at the same time of the day.

14
Baseline measurements
Athlete’s gender (male/female), age (years), weight (Kg) , height (cm) , medical history
and years of competition will be collected before the beginning of the study.

Ankle DF -ROM
Unilateral ankle DF -ROM will be assessed through the Weight -Bearing Lunge Test
(WBLT). A systematic review carried on by Powden et al (2015) demonstrated that it
should be used clinically to assess DF -ROM as it provides consistent and repeatable
results be tween one or more practitioners (6 2).
This measurement will be performed with a reliable, accurate and valid iPhone app for
the measurement of weight -bearing ankle dorsiflexion and inter -limb asymmetries (6 3),
called My ROM (© 2017 -20, Carlos Balsalobre -Fernández, Madrid, Spain), previously
called Dorsiflex. An almost perfect correlation was found between the digital
inclinometer and “My ROM ” for the ankle D F-ROM measurement (r = 0.989, 95% CI =
0.986 –0.993, SEE = 0.48ș).
Test procedures to measure the DF -ROM will be assessed following the methodology
previously described by Balsalobre -Fernández et al. This measurement will be performed
with the subject barefoot. F irstly, the athlete is asked to lunge their body forward as far
as possible, with the heel alwa ys in contact with the floor (weight -bearing lunge position).
Each subject will perform the WBLT with their hands on their hips. The iPhone has to be
set with the screen touching the tibia, specifically below the tibial tuberosity, with the Z –
axis of the d evice aligned with the tibia. Thereupon, it is needed to click in the button
“GO!” to begin with the measurement. The phone app starts a countdown of 5 seconds
and then, it registers the angle of inclination in the X -axis of the phone. Once this
procedure is done with both legs, the app shows the DROM of each limb, and also the
asymmetry percentage between both legs.
In the first assessment (pre -season), every athlete will perform two trials of the WBLT to
familiarize themselves with it and to reduce the p ossible “learning effect” influence.
For every measurement day, t hree trials will be performed with each leg. Ten seconds of
recovery between trials will be allowed. The best result for each limb among these 3 trials
will be selected for subsequent analysi s.

15
Pre-season DF -ROM measurement will be chosen to determine if it exists a limited ankle
DF-ROM at the beginning of the season. The difference between post -season DF -ROM
and pre -season DF -ROM will be calculated to investigate if this difference in ankle DF-
ROM influences the Achilles tendinopathy incidence.

Figure 2. Demonstration on the WBLT execution.

Achilles tendinopathy diagnosis
To calculate the I ncidence of Achilles tendinopathy is necessary to have the number of
diagnosed AT . Experienced physiotherapists will be in charge of diagnosing Achilles
tendinopathy. The diagnosis of AT will be always based on a complete history and
physical exam.
As there is no specific protocol/clinical guidelines to diagnose Achilles tendinopathy, the
next points will be considered: (1) Localised pain increased as tendon load increases. It
can be identified by recording tendon pain with a progressive loading stimulus. Double
leg heel ra ise, single -leg heel raise, double leg hop and single -leg hop will be the
progressive examination for AT. (2) Focalised pain in the Achilles region after the onset
of or after completing the training/competition. (3) Tendon pain/tenderness with
palpation, with or without the presence of nodules. (4) Self -report of morning stiffness.
(5) Self -report of pain (patient should point out where is his pain exactly located).

16
An ultrasound scan will be done , mainly to help the physiotherapist with the differential
diagnosis . It will also be seen if there is an increase in tendon diameter, areas of increased
water (hypoecho ic), collagen discontinuity and /or tendon sheath swelling.
It is important to consider that vague symptoms or symptoms that encompass a larger area
will be indicators of a different pain source.

Training frequency and number of competitions
Each subject will record his training frequency (training hours/week) and the number of
competitions during the season. An Excel document in the cloud will be provided. It will
be connected with us to be able to see the results instantly.

Internal load
Subjective internal load will be estimated using rate of perceived exertion (RPE), with
ratings obtained from each athlete 30 min utes after ending each training or competition,
following the methodology previously described by Foster et al. (6 1). It is important to
highlight that each track -and-field athlete will be familiarized with the RPE method
before starting this study. A n Excel d ocument in the cloud w ill be provided. It will be
connected with us to be able to see the results instantly.

Ankle plantar flexor (PF) strength
It will be measured with the maximum number of single -leg heel raises the athlete can
perform on flat ground, as previously described by Ross et al. (6 4). This measurement
will be done with the subject barefoot.

Outcomes
Primary out come
The primary outcome is the difference in DF-ROM at the end of the season compared to
DF-ROM at the beginning of the season .

Secondary outcome
The secondary outcome is Achilles tendinopathy incidence during the season .

17
Assessments
Pre-season assessment will be done on 30th September 2021 (2 weeks after the beginning
of the season) . Post-season assessment will take place on 30th July 2022. To assess the
internal load, training frequency and the number of competitions, each athlete will record
it every training and competition day (30 min after finishing the training/competition) . A
follow -up of the athletes on the same season (2021/2022) will be done. Physical therapists
in charge of doing the follow -up will contact the subjects every two weeks. They will be
available from Monday to Friday (9:00 AM -1:00 PM and 3:00 PM -7:00 PM). Phone
number to contact them will be provided.

Statistical Analysis
A univariate logistic regression model will be entered to determine the predictive power
of the difference in post-season DF-ROM compared to pre-season DF-ROM (quantitative
variable) on the Achilles tendinopathy incidence during the season (qualitative variable)
via the Wald -test. Baseline measurements, tr aining frequency, number of competitions,
internal load , PF strength and pre -season DF -ROM will be also studied to avoid
confounders . Results will be adjusted taking into account the value of these variables .
The confidence interval will be set at 95% and the level of significance will be set at 0.05
(5%) . All calculations will be performed using Stata statistical package version 16
(StataCorp LLC , Texas, U .S.A).

Ethics
All procedures described in this section will be applied following the requirements listed
in the Helsinki Declaration (World Medical Association, 1989), as well as the approval
of the Clinical Research Ethics Committee. All participants enrolled in this study must
sign a written informed consent form (see Annex I) before starting the study. Moreover,
all the participants will complete a general medical history form to verify inclusion
criteria.

18
Calendar/Planning

Figure 3. Study calendar .

Limitations
A limitation found in the present study is the difference in sport's shoes of each subject,
as it can vary the biomechanics of running, hurdling and gym exercises execution.
Differences in training is another limitation found. Although they commonly follow the
same or similar principles of training (as they all train for 400mH) and internal load will
be recorded, they are from different clubs and have different track -and-field coaches. So,
the training duration and exercises performed will not be exactly the same.

19
Another limitation found in this protocol is the effect of cold weather on the Achilles
tendon as a risk factor, as it is almost impossible to control it and it could negatively
influence on the risk of suffering an Achilles tendinopathy .

Role of the Investigators
A physiotherapist will recruit the subjects. A do ctor will evaluate the eligibility criteri a.
Six physi cal therapists will perform both assessments (two of them in each stadium) . Four
physiotherapist s will do the subjects follow -up. A biostatistics professional will analyse
the result s.

Resources
Six iPhone with the app “My ROM” installed to perform the ankle DF-ROM
measurements will be needed. A high-resolution ultrasound imaging device will be also
needed. A computer with Stata 16 installed will be used to analyse the results exported
from the app. Three a thletics stadiums will be used for the assessments. A team of 1 3
members in total will carry out the study.

20
References
1. van Sterkenburg MN, van Dijk CN. Mid-portion Achilles tendinopathy: why painful?
An evidence -based philosophy. Knee Surgery, Sports Traumatology, Arthroscopy.
2011;19(8):1367 -75.
2. Lopes AD, Hespanhol Júnior LC, Yeung SS, Costa LO. What are the main running –
related musc uloskeletal injuries? A Systematic Review. Sports Medicine.
2012;1;42(10):891 -905.
3. Cardoso, T. B., Pizzari, T., Kinsella, R., Hope, D., & Cook, J. L. Current trends in
tendinopathy management. Best Practice & Research Clinical Rheumatology. 2009;1 –
19.
4. Cook JL, Purdam CR. Is tendon pathology a continuum? A pathology model to explain
the clinical presentation of load -induced tendinopathy. British journal of sports medicine.
2009;1;43(6):409 -16.
5. Khan KM. Time to abandon the “tendinitis” myth. British Medical Journal.
2002;324(7338):626e7.
6. Jozsa L, Kannus P. Overuse injuries of tendons. Human tendons: anatomy, physiology
and pathology. Champaign: Human Kinetics. 1997;164 –253.
7. Maganaris CN, Narici MV, Maffulli N. Biomechanics of the Achilles tendo n.
Disability and Rehabilitation. 2008;30:1542 –1547.
8. Gaida, J. E., Ashe, M. C., Bass, S. L., & Cook, J. L. Is adiposity an under‐recognized
risk factor for tendinopathy? A systematic review. Arthritis Care & Research. 2009;61(6),
840-849.
9. Abate M, Schiavone C, Salini V, Andia I. Occurrence of tendon pathologies in
metabolic disorders. Rheumatology. 2013; 52(4):599e608.
10. Li H -Y, Hua Y -H. Achilles tendinopathy: current concepts about the basic science
and clinical treatments. BioMed Res earch International. 2016;9.
11. Mascaro A, Cos MA, Morral A, Roig A, Purdam C, Cook J. Load management in
tendinopathy: clinical progression for Achilles and patellar tendinopathy. Apunts.
Medicina de l’Esport. 2018;53(197):19e27.

21
12. Malliaras P, O'Neil l S. Potential risk factors leading to tendinopathy. Apunts.
Medicina de l’Esport. 2017;52(194):43e82.
13. McAuliffe S, McCreesh K, Culloty F, Purtill H, O'Sullivan K. Can ultrasound imaging
predict the development of Achilles and patellar tendinopathy? A systematic review and
meta -analysis. British Journal of Sports Medicine. 2016;50(24):1516.
14. Hart L. Corticosteroid and other injections in the management of tendinopathies: a
review. Clinical Journal of Sports Medicine. 2011 Nov;21(6):540 -1.
15. Vlist , A. C. Van Der, Breda, S. J., Oei, E. H. G., & Verhaar, J. A. N. Clinical risk
factors for Achilles tendinopathy : a systematic review. British Journal of Sports
Medicine. 2019;1352 –1361.
16. Dayton P. Anatomic, vascular, and mechanical overview of the A chilles tendon.
Clinics in Podiatric Medicine and Surgery. 2017;34(2):107e13.
17. Schubert, C. W. Achilles tendinosis is associated with sprouting of substance P
positive nerve fibres. Annals of the Rheumatic Diseases. 2005;1083 -1086.fckLR
18. Cook J, Purd am C. Is compressive load a factor in the development of tendinopathy?
British Journal of Sports Medicine. 2012;46(3):163e8
19. Khan KM, Forster BB, Robinson J, Cheong Y, Louis L, Maclean L, et al. Are
ultrasound and magnetic resonance imaging of value in assessment of Achilles tendon
disorders? A two -year prospective study. British Journal of Sports Medicine.
2003;37(2):149e53.
20. Docking SI, Ooi CC, Connell D. Tendinopathy: is imaging telling us the entire story?
Journal of Orthopaedic & Sports Physical Therapy. 2015; 45(11):842e52.
21. Dufour M, Pillu M. Biomecánica funcional. Masson (Elsevier). 2006;209.
22. Devita, P., & Skelly, W. A. Effect of landing stiffness on joint kinetics and energetics
in the lower extremity. Medicine & Science in Sports & Ex ercise. 1992;24(1), 108 -115.
23. Weir J, Chokalingam N. Ankle joint dorsiflexion: assessment of true values.
International Journal of Therapy and Rehabilitation. 2007;14(2):76 –82.
24. Moseley AM, Crosbie J, Adams R. High and low ankle flexibility and motor task
performance. Gait & Posture. 2003;18(2):73 –80.

22
25. Self BP, Paine D. Ankle biomechanics during four landing techniques. Medicine &
Science in Sports & Exercise. 2001;33(8):1338 –44.
26. Zhang SN, Bates BT, Dufek JS. Contributions of lower extremity jo ints to energy
dissipation during landings. Medicine & Science in Sports & Exercise. 2000;32(4):812 –
9.
27. Butler RJ, Crowell HP, Davis IM. Lower extremity stiffness: implications for
performance and injury. Clinical Biomechanics. 2003; 18(6):511 –7.
28. Mc Nitt-Gray JL, Requejo PS, Flashner H. Multijoint control strategies transfer
between tasks. Biological Cybernetics. 2006;94(6):501 –10.
29. Malliaras P, Cook JL, Kent P. Reduced ankle dorsiflexion range may increase the risk
of patellar tendon injury among volleyball players. Journal of Science and Medicine in
Sport. 2006 Aug;9(4):304 -9.
30. Backman LJ, Danielson P. Low range of ankle dorsiflexion predisposes for patellar
tendinopathy in junior elite basketball players: a 1 -year prospective study. American
Journal of Sports Medicine. 2011 Dec;39(12):2626 -33.
31. 27. Whitting, J. W., Steele, J. R., McGhee, D. E., & Munro, B. J. Dorsiflexion capacity
affects achilles tendon loading during drop landings. Medicine and Science in Sports and
Exercise. 2011;43(4), 7 06–713.
32. Bisseling, R. W., Hof, A. L., Bredeweg, S. W., Zwerver, J., & Mulder, T. Are the
take-off and landing phase dynamics of the volleyball spike jump related to patellar
tendinopathy? British Journal of Sports Medicine. 2008;42(6), 483 –489.
33. R abin, A., Kozol, Z., & Finestone, A. S. Limited ankle dorsiflexion increases the risk
for mid -portion Achilles tendinopathy in infantry recruits: a prospective cohort study.
Journal of foot and ankle research. 2014;7(1), 48.
34. Kaufman KR, Brodine SK, Sh affer RA et al. The effect of foot structure and range of
motion on musculoskeletal overuse injuries. American Journal of Sports Medicine. 1999;
27(5):585 –593.
35. Wahlstedt C., Rasmussen -Barr E. Anterior cruciate ligament injury and ankle
dorsiflexion. Kn ee Surgery, Sports Traumatology, Arthroscopy. 2015;23(11), 3202 –
3207.

23
36. Fong, C. M., Blackburn, J. T., Norcross, M. F., McGrath, M., Padua, D. A. Ankle –
dorsiflexion range of motion and landing biomechanics. Journal of athletic training.
2011;46(1), 5 -10.
37. Gabbe, B. J., Bennell, K. L., Finch, C. F., Wajswelner, H., & Orchard, J. W. Predictors
of hamstring injury at the elite level of Australian football. Scandinavian Journal of
Medicine and Science in Sports. 2006;16(1), 7 –13.
38. Gabb e B. J., Finch C. F., Bennell K. L., Wajswelner H. Risk factors for hamstring
injuries in community level Australian football. British Journal of Sports Medicine.
2005;39(2), 106 –110.
39. van Dyk N., Farooq A., Bahr R., Witvrouw E. Hamstring and ankle fle xibility Deficits
Are Weak risk factors for hamstring injury in professional soccer players: A prospective
cohort study of 438 players including 78 injuries. The American Journal of Sports
Medicine. 2018;6(9), 2203 –2210.
40. Macrum E., Bell D. R., Boling M., Lewek M., Padua, D. Effect of limiting ankle –
dorsiflexion range of motion on lower extremity kinematics and muscle -activation
patterns during a squat. Journal of sport rehabilitation. 2012;21(2), 144 -150.
41. Piva, S. R., Goodnite, E. A., & Childs, J. D. Strength around the hip and flexibility of
soft tissues in individuals with and without patellofemoral pain syndrome. Journal of
orthopaedic & sports physical therapy. 2005;35(12), 793 -801.
42. Denegar CR, Miller III SJ. Can chronic ankle instability be prevented? Rethinking
management of lateral ankle sprains. Journal of Athletic Training. 2002;37:430.
43. Charlton P. C., Raysmith B., Wollin M., Rice S., Purdam C., Clark R. A., Drew M.
K. Knee flexion strength is significantly reduced following competit ion in semi –
professional Australian Rules football athletes: Implications for injury prevention
programs. Physical Therapy in Sport. 2018;31, 9 –14.
44. Bennell K., Talbot R., Wajswelner H., Techovanich W., Kelly D. Intra -rater and inter –
rater reliability of a weight -bearing lunge measure of ankle dorsiflexion. Australian
Journal of Physiotherapy. 1998;44(3), 175 –180.

24
45. Dill K. E., Begalle R. L., Frank B. S., Zinder S. M., Padua D. A. Altered knee and
ankle kinematics during squatting in those with limited weight -bearing -lunge ankle –
dorsiflexion range of motion. Journal of Athletic Training . 2014; 49(6), 723 –732.
46. Lindeman R. 400m hurdle theory. Track Coach . 1995; (131), 4169 -4171, 4196.
47. Winckler G. V. Gambetta (Ed.). Hurdling. The Athletics Co ngress’s Track and Field
Manual . Human Kinetics. 1989;73 -87.
48. Jolly S. V. Gambetta (Ed.). 400m hurdles. The Athletics Congress’s Track and Field
Manual. Human Kinetics. 1989;89 -92.
49. Mcfarlane B. Understanding the 400metre hurdles. Track & Field Quar terly Review.
1980;80(2), 65 -58.
50. Winckler G. J. L. Rogers (Ed.). 400m hurdles. USA Track & Field Coaching Manual.
Human Kinetics. 2000;75 -91.
51. Przednowek K, Iskra J, Wiktorowicz K, Krzeszowski T, Maszczyk A. Planning
training loads for the 400 m hur dles in three -month mesocycles using artificial neural
networks. Journal of Human Kinetics. 2017; 60. 175 –189.
52. Hanon C, Gajer B. Velocity and stride parameters of world -class 400 -meter athletes
compared with less experienced runners. Journal of Streng th Conditioning Research.
2009; 23(2): 524 –531.
53. Ozaki Y., Ueda T., Fukuda T., Inai T., Kido E., Narisako D. Regulation of Stride
Length During the Approach Run in the 400 ‐ M Hurdles. Journal of Human Kinetics.
2019;69.
54. Beaulieu P, Ottoz H, Grang e C, Thomas J, Bensch C. Blood lactate levels of
decathletes during competition. British Journal of Sports Medicine. 1995; 29(2): 80 –84.
55. Hannon C, Thomas C. Effects of optimal pacing strategies for 400 -, 800 -, and 1500 –
m races on the VO2 response. Journal of Sports Sciences. 2011; 29(9): 905 –912.
56. Hirvonen J, Nummela A, Rusko H, Rehunen S, Härkönen M. Fatigue and changes of
ATP, creat ine phosphate, and lactate during the 400 -m sprint. Canadian journal of sport
sciences. 1992;17(2): 141 –144.

25
57. Nummela A, Vuorimaa, Rusko H. Changes in force production, blood lactate and
EMG activity in the 400 -m sprint. Journal of Sports Sciences. 199 2;10(3): 217 –228.
58. Saraslanidis PJ, Panoutsakopoulos V, Tsalis GA, Kyprianou E. The effect of different
first 200 -m pacing strategies on blood lactate and biomechanical parameters of the 400 –
m sprint. European Journal of Applied Physiology. 2011;111(8): 1579 –1590.
59. Zouhal H, Jabbour G, Jacob C, Duvigneau D, Botcazou M, Ben Abderrahaman A et
al. Anaerobic and aerobic energy system contribution to 400 -m flat and 400 -m hurdles
track running. Journal of Strength and Conditioning Research. 2010; 24(9): 23 09–2315.
60. Quinn M. D. External Effects in the 400 -m Hurdles Race. Journal of Applied
Biomechanics. 2010;26(2), 171 –179.
61. Foster C, Florhaug JA, Franklin J, Gottschall L, Hrovatin LA, Parker S, Doleshal P,
Dodge C. A new approach to monitoring exerc ise training. Journal of Strength and
Conditioning Research. 2001;15(1):109 -15.
62. Powden C. J., Hoch J. M., & Hoch M. C. Reliability and minimal detectable change
of the weight -bearing lunge test: A systematic review. Manual Therapy. 2015;20 (4);524 –
532.
63. Balsalobre -Fernández C., Romero -Franco N., Jiménez -Reyes P. Concurrent validity
and reliability of an iPhone app for the measurement of ankle dorsiflexion and inter -limb
asymmetries. Journal of Sports Sciences. 2019;37(3), 249 –253.
64. Ross M, Fontenot E. Test -retest reliability of the standing heel rise test. Journal of
Sport Rehabilitation. 2000;9:117 — 23.
65. Cook J, Alfredson H. A treatment algorithm for managing Achilles tendinopathy.
British Journal of Sports Medicine. 2007;211 –216.
66. Cook J. L., Khan K. M., Purdam C. Achilles tendinopathy. Manual Therapy. 2002;7,
121–130.
67. Reiman M., Burgi C., Strube E., Prue K., Ray K., Elliott A., Goode A. The Utility of
Clinical Measures for the Diagnosis of Achilles Tendon Injuries: A Systematic Review
With Meta -Analysis. Journal of Athletic Training. 2014;49(6), 820 –829.

26
Annex I : Informed consent

PART I: Information Sheet

Introduction
I am Aday Sousa, a fourth year student performing a scientific study for the final project
at the University School of Health and Sport (EUSES), affiliated to the University of
Girona (UdG). I am going to give you information and invite you to be part of this
research. You do not have to decide today whether or not you will participate in the
research. Before you decide, you can talk to anyone you feel comfortable with about the
research.
There may be some words that you do not understand. Please ask me personally or by e –
mail to adaysm98@gmail.com as you go through the information and I will take time to
explain.

Purpose of the research
A limited ankle dorsiflexion range of motion (DF -ROM) has been identified as a risk
factor for several musculoskeletal conditions in different sports disciplines . However, no
research has investigated the relationship of a decrease in ankle dorsiflexion with Achilles
tendinopathy incidence in athletics, and specifically in the 400 -m hurdles. Therefore, the
purpose of this study is to investigate the relationship between DF-ROM at the end of the
season compared to the DF-ROM at the beginning of the season and Achilles
tendinopathy incidence in healthy male 400 -m hurdles track -and-field athletes following
a whole season.

Type of Research Intervention
This research will involve 2 assessments: (1) at the beginning of the season (pre -season)
and ( 2) at the end of the season (post -season). A follow -up will be done during the same
season (2021/2022).

27
Participant selection
We are inviting all adults aged between 18 -35 years old practicing 400m hurdles who are
affiliated to the Catalan Athletics Federation to participate in the research on the
relationship between dorsiflexion range of motion and Achilles tendinopathy incidence.

Voluntary Participation
Your participation in this research is entirely voluntary. It is your choice whether to
participate or not. You may change your mind later and stop participating even if you
agreed earlier .

Description of the process
During the research you make 2 visits to the assigned athletics stadium in Barcelona.
• In the first visit, on September 30th 2020, the pre -season assessment will take place. A
measurement of ankle dorsiflexion range of motion (D F-ROM) will be performed
through weight -bearing lunge test . Plantar flexor (PF) strength will be assessed with the
maximum number of single -leg heel raises the athlete can perform on flat ground .
• In the second visit, on 30th July 2021, you will come back to the stadium assigned for
the post -season assessment. Ankle DF -ROM and PF strength be measured through the
same method.
A follow -up of athletes on the same season (2021/2022) will be done. Physical therapists
in charge of doing the follow -up will contact the subjects every two weeks. They will be
available from Monday to Friday (9:00 AM -1:00 PM and 3:00 PM -7:00 PM). Phone
number to contact them will be provided.

Duration
The research takes place over 2021/2022 season . During that time, it will be necessary
for you to come to the assigned stadium 2 days , for approximately 30 minutes each day.
We would like to do a follow -up during the same season.
In total, you will be asked to come 2 times to the assigned stadium in 11 months. At the
end of the season 2021/2022, the research will be finished.

28
Confidenciality
The information that we collect from this research project will be kept confidential.
Information about you that will be collected during the research will be pu t away and no –
one but the researchers will be able to see it. Any information about you will have a
number on it instead of your name. Only the researchers will know what your number is.
It will not be shared with or given to anyone.

Sharing the Results
The knowledge that we get from doing this research will be shared with you through
community meetings before it is made widely available to the public. Confidential
information will never be shared. After these meetings, we will publish the results in order
that other interested people may learn from our research.

Right to Refuse or Withdraw
You do not have to take part in this research if you do not wish to do so. You may also
stop participating in the research at any time you choose. It is your c hoice and all of your
rights will still be respected.

Who to Contact
If you have any questions you may ask them now or later, even after the study has started.
If you wish to ask questions later, you may contact the following e -mail:
adaysm98@gmail.com .

29
PART II: Certificate of Consent
I have read the foregoing information, or it has been read to me. I have had the
opportunity to ask questions about it and any questions that I have asked have been
answered to my satisfaction. I consent voluntarily to participate as a participant in
this research.

Print Name of Participant__________________
Signature of Participant ___________________
Date ___________________________
Day/month/year

Statement by the researcher
I have accurately read out the information sheet to the potential participant, and to
the best of my ability made sure that the participant understands all the information
provided concerning this research.
I confirm that the participan t was given an opportunity to ask questions about the
study, and all the questions asked by the participant have been answered correctly
and to the best of my ability. I confirm that the individual has not been coerced into
giving consent, and the consent has been given freely and voluntarily.
A copy of this informed consent has been provided to the participant.

Print Name of Researcher ________________________
Signature of Researcher__________________________
Date ___________________________
Day/month/year