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Achilles Tendinopathy (AT)NCT07623408

Effect of Foot Position During Rehabilitation of Achilles Tendinopathy on Tendon Mechanics and Symptoms.

A study testing 12-week adaptive, load-based exercise therapy protocol for Achilles Tendinopathy in people with Achilles Tendinopathy (AT), run by KU Leuven at 1 site in Belgium.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

This study will investigate whether a 12-week load-based exercise program performed with an externally rotated foot position ("toes-out") leads to different changes in intra-tendinous sliding, symptoms, and function compared to a standard exercise program performed with a neutral foot position in individuals with… Read more about this study

Who is it for?
Ages 18 to 65 years
Conditions the study is for
Achilles Tendinopathy (AT)
What is being tested?
12-week adaptive, load-based exercise therapy protocol for Achilles Tendinopathy
Could I receive a placebo?
No, everyone receives an active treatment
How many people
60 participants
Where
1 siteBelgium
Study dates
19 Feb 2026to 31 Aug 2027
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 65 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

The following inclusion criteria will be used:

PATIENTS WITH ACHILLES TENDINOPATHY:

  • Voluntary written Informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures.
  • Age between 18 and 65 years old
  • BMI between 18.5-30
  • Showing history of intermittent episodes of Achilles tendon pain lasting more than 3 consecutive weeks within the past 6 months.
  • Presenting palpable focal thickening of the Achilles tendon.
  • Having pain originating from the Achilles tendon on palpation of thickened tendon and on loading activities (such as running, jumping).
  • Showing sonographic evidence of tendinopathy, i.e. focal thickening and hypoechocity, consistent with previously reported sonographic characteristics diagnosed of tendinopathy.

Prior to start of the data collection, these inclusion criteria (specifically the ones concerning Achilles Tendinopathy presence) will be checked by a medical doctor at SMAC (Sports medical advisory centre Leuven). Only if they confirm the diagnosis, patients are included in the study.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Laura Lecompte, Msc contact

+32499263609

laura.lecompte@kuleuven.be

Marion Crouzier, PhD contact

+33 620045744

marion.crouzier@univ-nantes.fr

Belgium1 site, 1 recruiting

  • KU Leuven

    Leuven, Vlaams-Brabant, 3000

    Benedicte Vanwanseele, Prof, +32499263609, benedicte.vanwanseele@kuleuven.be

    Recruiting

Other trials in Belgium

About this study

Official title: The Effect of Foot Positioning During a 12-week Supervised Training Program on Achilles Tendon Mechanics and Function in Individuals With Mid-portion Achilles Tendinopathy.

This study will investigate whether a 12-week load-based exercise program performed with an externally rotated foot position ("toes-out") leads to different changes in intra-tendinous sliding, symptoms, and function compared to a standard exercise program performed with a neutral foot position in individuals with mid-portion Achilles tendinopathy. In addition, physical activity will be monitored during and after the intervention to examine how daily loading patterns relate to symptoms and functional recovery over a 6-month period.

Read the detailed description

Achilles tendinopathy is a common overuse disorder characterized by pain, swelling, and impaired function, with substantial impact on sports participation and quality of life. Despite exercise therapy being considered the gold standard treatment, rehabilitation outcomes remain suboptimal, with a considerable proportion of patients reporting persistent symptoms and many failing to return to their preferred level of sport. This highlights the need to improve current rehabilitation strategies and better understand mechanisms underlying tendon recovery.

The Achilles tendon is mechanically complex, as it is loaded by the triceps surae muscle group and can be considered to consist of three partially independent subtendons that slide relative to each other. This intra-tendinous sliding has been investigated during passive and active loading tasks and may represent an important feature of healthy tendon behavior. It has been proposed that sliding may help distribute stress within the tendon and may contribute to tendon adaptation through local shear-related mechanobiological responses.

Emerging evidence suggests that intra-tendinous sliding is altered in tendinopathy. Previous work has demonstrated reduced sliding in pathological tendons compared to healthy controls, while external foot rotation ("toes-out") has been shown to increase sliding during isometric and dynamic loading tasks. These findings raise the possibility that modifying foot position during rehabilitation exercises may influence internal tendon loading and promote more favorable adaptations. However, no studies have investigated changes in intra-tendinous sliding longitudinally during an exercise therapy program or whether modifying foot position during rehabilitation affects clinical outcomes.

This study will therefore compare two 12-week load-based rehabilitation programs for individuals with mid-portion Achilles tendinopathy: a standard program performed with a neutral foot position and an adapted program performed with an externally rotated foot position. The study will investigate whether these interventions lead to different changes in intra-tendinous sliding, tendon morphology, symptoms, and functional recovery.

In addition to the prescribed exercise intervention, the study will investigate the role of daily physical activity in rehabilitation outcomes. Tendon loading occurs not only during structured exercise therapy but also through habitual and sport-related activity, which may influence recovery. However, little is currently known about how physical activity patterns change during and after rehabilitation or how these patterns relate to symptoms and function.

Physical activity will therefore be monitored throughout the intervention and follow-up period to evaluate changes in activity behavior over time and to explore associations between daily loading patterns, symptom progression, and functional outcomes. By combining evaluation of tendon-specific mechanical adaptations with monitoring of physical activity behavior, this study aims to provide new insights into factors influencing recovery in Achilles tendinopathy and to inform optimization of rehabilitation strategies.

Being tested
12-week adaptive, load-based exercise therapy protocol for Achilles Tendinopathy
Keywords
Achilles Tendinopathy, Exercise therapy program, Achilles Tendon, Rehabilitation, Foot position, homogeneous motions

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 12-week adaptive, load-based exercise therapy protocol for Achilles TendinopathyOther

    A 12-week progressive, load-based exercise program was developed, consisting of four daily exercises with gradually increasing tendon load over time. The program was based on the exercise battery and according Achilles Tendon loading index described by Baxter et al. (2021) and included a wide variety of 30 exercises (heel raise variations, step exercises, squats, lunges, jump variations, ...). A new exercise was introduced every four days, while weekly supervised sessions ensured correct execution and allowed for adjustments based on patient tolerance (e.g., excessive knee loading, too high pain scores during specific exercises, …). This flexible approach enabled gradual progression of each participant's daily load index according to individual capacity. An estimated time of 20-30 minutes daily is needed to execute all the daily exercises.

Study groups in NCT07623408
Study groupRoleWhat they receive
Toes-out Training GroupExperimentalPatients in this group will perform the 12-week load-based exercise program, and will execute all exercises daily througout the full program with toes-out (the feet horizontally outwards rotated). For this toes-out angle, their individual, most comfortable angle is chosen.
Receives: Other: 12-week adaptive, load-based exercise therapy protocol for Achilles Tendinopathy
Neutral Training GroupActive comparatorPatients in this group will perform the 12-week load-based exercise program, and will execute all exercises daily througout the full program with a neutral foot position.
Receives: Other: 12-week adaptive, load-based exercise therapy protocol for Achilles Tendinopathy

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Intra-tendinous sliding between Achilles tendon layers (derived from ultrasound imaging and analyzed using a speckle tracking algorithm)

    Ultrasound images of the Achilles tendon will be recorded using a probe (Hitachi L64, Tokyo, Japan) put in an external probeholder during multiple rehabilitation exercises: Birise Bidrop Standing, Unirise Unidrop Standing Knee Extended, Unirise Unidrop Standing Knee Bent and squat. The device we will use is the Arietta 650, FUJIFILM, which allows to record B-mode ultrasound images. The probe will be placed distally on the Achilles tendon, just above the calcaneal insertion (used as reference point). Using a speckle tracking algorithm in Matlab, the displacement of 6 rows within the Achilles tendon is calculated. Intra-tendinous sliding is calculated as the relative difference between the displacement of the superficial and deep border.

    Measured: Measured during the pre and posttest, respectively the week before and after the 12-week exercise therapy program

  2. Clinical outcomes after Achilles Tendinopathy rehabilitation: Achilles Tendinopathy symptoms based on VISA-A questionnaire

    At pretest, 3, 6, 9, posttest, 15, 18, 21, and 24, the VISA-A questionnaire will be completed online. During the pre- and post-test assessments, participants will complete the questionnaire on a laptop provided in the lab, ensuring it is administered online and in the same manner as throughout the intervention, where they fill it in at home.

    The VISA-A questionnaire is an 8-item survey used to assess the severity of Achilles tendinopathy. It evaluates pain, daily functional activities, and sporting ability, with scores ranging from 0 to 100, where a score of 100 indicates no symptoms.

    Measured: Pretest (one week before the 12-week program), Posttest (one week after the 12-week program), and at week 3,6,9,15,18,21 and 24.

  3. Clinical outcomes after Achilles Tendinopathy rehabilitation: Achilles Tendon functionality based on heel-rise test

    Heel-rise test: participants perform as many heel-raises as possible at a frequency of 25 per minute (controlled by a metronome). The test will be discontinued when the participant does not reach maximum height, cannot keep the frequency, cannot keep the knee straight or stops due to pain or fatigue. By using an application, the foot will be filmed and heel work will be calculated.

    Measured: Pretest (one week before the 12-week program) and Posttest (one week after the 12-week program)

  4. Clinical outcomes after Achilles Tendinopathy rehabilitation: Achilles Tendon functionality based on hopping till pain test

    • Hopping till pain: the participant hops on a single leg at a pace of 2 jumps per second (controlled by a metronome) where the goal is to achieve 25 pain-free hops, but the test will be stopped when the participant starts to experience pain.

    Measured: pretest (one week before the 12-week program) and posttest (one week after the 12-week program)

Secondary outcomes (9)

  1. Questionnaire Data: Quality of Life (SF-12 questionnaire)

    SF-12 questionnaire: used to assess health-related quality of life.

    Measured: Pretest (one week before the 12-week training program), Posttest (one week after the 12-week training program), week 3,6,9,15,18,21,24

  2. Doppler Vascularity

    Intra-tendinous vascularity will be assessed in the sagittal plane with Doppler Ultrasonography (Arietta 650, FUJIFILM). The ultrasound transducer will be aligned parallel to the tendon and will be applied with no pressure and it will be positioned so that it visualizes the proximal portion of the calcaneal bone and the Achilles tendon. For this, participants will be in prone position with the knee extended and the ankle joint passively stabilized at 90°. Three scans with a duration of 4 seconds will be recorded at both the insertion and midportion of the tendon after all rehabilitation exercises in the lab are performed.

    Measured: Pretest and posttest, respectively one week before and after the 12-week exercise therapy program

  3. Morphological features of the Achilles tendon (free Achilles tendon length and volume)

    During rest in the prone position, multiple scans of the lower leg will be acquired using 3D freehand ultrasound. This technique combines conventional B-mode ultrasonography (FUJIFILM Healthcare, Arietta 650DI) with a motion analysis system to generate in vivo three-dimensional reconstructions of tendon structures. The 2D ultrasound images will be transformed into a global coordinate system using the open-source medical image computing and visualization software 3D Slicer, enabling reconstruction of a 3D tendon volume. Based on this technique, the length and volume of the free Achilles tendon (AT) will be estimated.

    As a supplementary check, free AT length will also be measured manually by determining the distance between the calcaneal insertion and the soleus myotendinous junction, identified using ultrasound imaging. In addition, two ultrasound images (transverse and sagittal planes) will be obtained at the swollen region of the tendon to provide indications of tendon width.

    Measured: Pretest and posttest, respectively one week before and after the 12-week exercise therapy program

  4. Lower extremity biomechanics during rehabilitation exercises: kinematics, kinetics, muscle activations, muscle forces and cumulative Achilles Tendon load through musculoskeletal modeling (assesed with 3D motion and ground reaction force capturing)

    In the lab, patients will perform four rehabilitation exercises: Bilateral heel raise-drop, unilateral heel raise-drop (knee extended and knee bent version) and squat. Besides that, walking and optionally (if the patient can) running on the treadmill. 3D-motion capture data, EMG (Delsys electrodes) and force plate data will be collected. Through musculoskeletal modeling in OpenSim, Kinematics, kinetics, muscle activations and forces (of Gastrocnemius medialis (GM) and lateralis (GL), soleus (SOL), tibialis posterior and anterior and peroneus) will be analyzed. Besides that, EMG will be recorded through Delsys electrodes on Gastrocnemius medialis and lateralis, soleus, tibialis anterior and peroneus.

    Achilles Tendon Load will be calculated as the sum of the tendon force from GM, GL and SOL from the musculoskeletal model - muscle analysis after dynamic optimization.

    Measured: During the pretest and posttest in the lab, respectively one week before and after the 12-week training program

  5. Physical activity throughout the training program

    Throughout the training program (and also the 12 weeks after as follow-up), all patients wear a Fitbit Inspire 3. This activity tracker will measure the physical activity of the patient. Most important features here are amount of daily steps and automatically tracked activities (cycling, swimming, running, walking) with according time. Besides that, all patients have a logbook where they write down every week as well which activities they did as an extra check-up.

    (The logbook is only used during the training program).

    Measured: Daily for 6 months: 12 weeks during the training program and 12 weeks after the training program.

  6. Interview on patient perception after the training program

    During the post-test assessment in the lab, following the 12-week training program, a live interview will be conducted with each participant. The principal investigator will ask questions regarding the participant's experiences with the training program. The interview will include both open-ended questions and closed-ended questions using a Likert scale. It will take approximately 10 minutes and will provide important information regarding the feasibility of the program for patients performing 30 minutes of exercises daily.

    Measured: Posttest in the lab (week after the 12-week training program)

  7. Questionnaire Data: Achilles Tendinopathy symptoms (TENDINS-A questionnaire)

    TENDINS-A questionnaire: a patient-reported outcome measure (PROM) designed to assess the severity of disability in individuals with Achilles tendinopathy. It evaluates pain, symptoms, and physical function to determine the impact of the condition on daily life. As this questionnaire was only recently developed and published in 2024, limited research is available on how its outcomes relate to the VISA-A. Therefore, collecting both measures at pre- and post-test will allow comparison between the two instruments.

    Measured: Pretest (one week before the 12-week training program), Posttest (one week after the training program), week 3,6,9,15,18,21,24

  8. Questionnaire Data: return to sport (13-item FRESS questionnaire)

    13-item FRESS questionnaire: used to assess return-to-sport outcomes.

    Measured: Pretest (one week before the 12-week training program), Posttest (one week after the 12-week training program), week 3,6,9,15,18,21,24

  9. Questionnaire Data: fear of movement (Tampa Scale for Kinesiophobia (TSK))

    Tampa Scale for Kinesiophobia (TSK): used to assess fear of movement and reinjury.

    Measured: Pretest (one week before the 12-week training program), Posttest(one week after the 12-week training program), week 3,6,9,15,18,21,24

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted3 Jun 2026
  2. Study start19 Feb 2026
  3. Primary completion31 Aug 2027 (estimated)
  4. Study completion31 Aug 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
Two groups will follow the same exercise therapy program of 12 weeks with daily exercises for Achilles Tendinopathy where the intensity gradually increases over the weeks. One group will perform all exercises in a Neutral foot position whereas the other group will perform all exercises with the toes outwards rotated (toes-out foot position).
Masking
Single blind
Who is masked
Participant
Enrolment
60 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07623408
Sponsor's protocol ID
S68515
Status last verified
May 2026
First submitted
5 May 2026
Last updated
3 Jun 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: Individual data of all outcome measures (primary and secondary outcome parameters) will be analyzed and shared upon request.

Publications

  • Lecompte L, Crouzier M, Bogaerts S, Scheys L, Vanwanseele B. Reduced Intratendinous Sliding in Achilles Tendinopathy During Active Plantarflexion Regardless of Horizontal Foot Position. Scand J Med Sci Sports. 2024 Jun;34(6):e14679. doi: 10.1111/sms.14679.

    PubMed 38898554

  • Lecompte L, Crouzier M, Bogaerts S, Vanwanseele B. Patients with Achilles Tendinopathy Show Reduced Intratendinous Sliding during Dynamic Exercises. Med Sci Sports Exerc. 2026 Jun 1;58(6):1149-1158. doi: 10.1249/MSS.0000000000003942. Epub 2026 Jan 22.

    PubMed 41572520

  • de Vos RJ, van der Vlist AC, Zwerver J, Meuffels DE, Smithuis F, van Ingen R, van der Giesen F, Visser E, Balemans A, Pols M, Veen N, den Ouden M, Weir A. Dutch multidisciplinary guideline on Achilles tendinopathy. Br J Sports Med. 2021 Oct;55(20):1125-1134. doi: 10.1136/bjsports-2020-103867. Epub 2021 Jun 29.

    PubMed 34187784

  • Turner J, Malliaras P, Goulis J, Mc Auliffe S. "It's disappointing and it's pretty frustrating, because it feels like it's something that will never go away." A qualitative study exploring individuals' beliefs and experiences of Achilles tendinopathy. PLoS One. 2020 May 29;15(5):e0233459. doi: 10.1371/journal.pone.0233459. eCollection 2020.

    PubMed 32469914

  • Thorpe CT, Udeze CP, Birch HL, Clegg PD, Screen HR. Specialization of tendon mechanical properties results from interfascicular differences. J R Soc Interface. 2012 Nov 7;9(76):3108-17. doi: 10.1098/rsif.2012.0362. Epub 2012 Jul 4.

    PubMed 22764132

  • Tardioli A, Malliaras P, Maffulli N. Immediate and short-term effects of exercise on tendon structure: biochemical, biomechanical and imaging responses. Br Med Bull. 2012 Sep;103(1):169-202. doi: 10.1093/bmb/ldr052. Epub 2012 Jan 25.

    PubMed 22279080

  • Slane LC, Thelen DG. Non-uniform displacements within the Achilles tendon observed during passive and eccentric loading. J Biomech. 2014 Sep 22;47(12):2831-5. doi: 10.1016/j.jbiomech.2014.07.032. Epub 2014 Aug 8.

    PubMed 25150898

  • Sancho I, Willy RW, Morrissey D, Malliaras P, Lascurain-Aguirrebena I. Achilles tendon forces and pain during common rehabilitation exercises in male runners with Achilles tendinopathy. A laboratory study. Phys Ther Sport. 2023 Mar;60:26-33. doi: 10.1016/j.ptsp.2023.01.002. Epub 2023 Jan 10.

    PubMed 36640640

  • Robinson JM, Cook JL, Purdam C, Visentini PJ, Ross J, Maffulli N, Taunton JE, Khan KM; Victorian Institute Of Sport Tendon Study Group. The VISA-A questionnaire: a valid and reliable index of the clinical severity of Achilles tendinopathy. Br J Sports Med. 2001 Oct;35(5):335-41. doi: 10.1136/bjsm.35.5.335.

    PubMed 11579069

  • Radovanovic G, Bohm S, Peper KK, Arampatzis A, Legerlotz K. Evidence-Based High-Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross-Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial. Sports Med Open. 2022 Dec 20;8(1):149. doi: 10.1186/s40798-022-00545-5.

    PubMed 36538166

  • van der Plas A, de Jonge S, de Vos RJ, van der Heide HJ, Verhaar JA, Weir A, Tol JL. A 5-year follow-up study of Alfredson's heel-drop exercise programme in chronic midportion Achilles tendinopathy. Br J Sports Med. 2012 Mar;46(3):214-8. doi: 10.1136/bjsports-2011-090035. Epub 2011 Nov 10.

    PubMed 22075719

  • Passini FS, Jaeger PK, Saab AS, Hanlon S, Chittim NA, Arlt MJ, Ferrari KD, Haenni D, Caprara S, Bollhalder M, Niederost B, Horvath AN, Gotschi T, Ma S, Passini-Tall B, Fucentese SF, Blache U, Silvan U, Weber B, Silbernagel KG, Snedeker JG. Shear-stress sensing by PIEZO1 regulates tendon stiffness in rodents and influences jumping performance in humans. Nat Biomed Eng. 2021 Dec;5(12):1457-1471. doi: 10.1038/s41551-021-00716-x. Epub 2021 May 24.

    PubMed 34031557

  • Maffulli N, Sharma P, Luscombe KL. Achilles tendinopathy: aetiology and management. J R Soc Med. 2004 Oct;97(10):472-6. doi: 10.1177/0141076809701004. No abstract available.

    PubMed 15459257

  • Kujala UM, Sarna S, Kaprio J. Cumulative incidence of achilles tendon rupture and tendinopathy in male former elite athletes. Clin J Sport Med. 2005 May;15(3):133-5. doi: 10.1097/01.jsm.0000165347.55638.23.

    PubMed 15867554

  • Gheidi N, Kernozek TW, Willson JD, Revak A, Diers K. Achilles tendon loading during weight bearing exercises. Phys Ther Sport. 2018 Jul;32:260-268. doi: 10.1016/j.ptsp.2018.05.007. Epub 2018 May 10.

    PubMed 29906737

Questions about this trial

What is this clinical trial studying?

A study testing 12-week adaptive, load-based exercise therapy protocol for Achilles Tendinopathy in people with Achilles Tendinopathy (AT), run by KU Leuven at 1 site in Belgium.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 3 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Laura Lecompte, Msc (+32499263609, laura.lecompte@kuleuven.be), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Intra-tendinous sliding between Achilles tendon layers (derived from ultrasound imaging and analyzed using a speckle tracking algorithm) (time frame: Measured during the pre and posttest, respectively the week before and after the 12-week exercise therapy program). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07623408, which also lists 23 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Jun 2026.

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