Effectiveness of Isometric vs. Eccentric Exercise in Chronic Achilles Tendinopathy

Study Overview
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Brief Summary
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This is a prospective single blinded randomised controlled trial with a 12-week intervention period and a half-year follow-up period. The main purpose is to determine the effects of isometric exercise on mechanical, morphological and functional tendon properties versus eccentric exercise in chronic Achilles tendinopathy.

Detailed Description
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This research project was funded by means of the Bundesinstitut für Sportwissenschaft based on a resolution of the German Federal Parliament.

Official Title
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Effectiveness of Eccentric Exercise Compared to Isometric Exercise in Athletes With Chronic Achilles Tendinopathy

Conditions
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Tendinopathy

Intervention / Treatment
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* Other: Isometric exercise
* Other: Eccentric exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Chronic (3 months or more) condition of unilateral Achilles tendinopathy confirmed by a medical doctor based on ultrasound age 18-60 male VISA-A Score of at least 80 Exclusion Criteria: bilateral tendinopathy any systemic or inflammatory diseases (i. e. Diabetes, Arthritis) surgery on lower extremities in the past corticoid injections in the last 12 months

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Isometric exercise<br>Isometric exercise (90% maximum voluntary contraction (MVC), 12 weeks, 4 times a week, 5 sets of 4 repetitions a 3 seconds) | Other: Isometric exercise<br> <br> |
| Active Comparator: Eccentric exercise<br>Eccentric training (Alfredson approach, 12 weeks, 2 sets per day with extended and two sets per day with bended knee, 15 repetitions per set) | Other: Eccentric exercise<br> <br> |
| No Intervention: Control<br>Control, no intervention | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Morphological tendon properties, Tendon cross sectional area (CSA) | Equipment Magnetic resonance imaging (MRI) (0.25 T MR Scanner (Esaote, G-Scan, Italy), T1-Gewichtung, 3D HYCE (GR) Sequency, TR 10 ms, TE 5 ms, flip angle 80°, layer thickness 3 mm, 1 Anregung) Software OsiriX (Pixmeo SARL, Version 2.5.1., Schweiz) Tendon thickness / cross sectional area (CSA) in square millimeter (mm²) through MRI, manually outlined via Software OsiriX (Pixmeo SARL, Version 2.5.1., Schweiz). The mean value of three measurements of the same image will be used for analysis. In order to demonstrate local changes within the tendon, CSA will be shown in 10% intervals relative to the total length of the tendon. | At baseline and 12 weeks after | 
| Mechanical tendon properties, Tendon stiffness | Equipment Dynamometer (Biodex System 3, Medical Systems Inc., USA), optical motion capture system with eight cameras with a frequency of 250 Hertz (Hz) (Vicon Nexus, version 1.7.1., Vicon Motion Systems, UK), electromyography (Myon m320RX, Myon AG, Schweiz) and a linear ultrasound (7.5 Megahertz (MHz), ESAOTE MyLab 60) Tendon stiffness in Newton per mm (N/mm) with support of tendon force in Newton (N) | At baseline and 12 weeks after | 
| Mechanical tendon properties, Modulus | Equipment Dynamometer (Biodex System 3, Medical Systems Inc., USA), optical motion capture system with eight cameras with a frequency of 250 Hertz (Hz) (Vicon Nexus, version 1.7.1., Vicon Motion Systems, UK), electromyography (Myon m320RX, Myon AG, Schweiz) and a linear ultrasound (7.5 Megahertz (MHz), ESAOTE MyLab 60) Modulus in Pascal (Pa) based on tendon stress (Pa) and tendon elongation in millimeter (mm) | At baseline and 12 weeks after | 
| Morphological tendon properties, Tendon length | Equipment Magnetic resonance imaging (MRI) (0.25 T MR Scanner (Esaote, G-Scan, Italy), T1-Gewichtung, 3D HYCE (GR) Sequency, TR 10 ms, TE 5 ms, flip angle 80°, layer thickness 3 mm, 1 Anregung) Software OsiriX (Pixmeo SARL, Version 2.5.1., Schweiz) Tendon length im millimeter (mm) through MRI, manually outlined via Software OsiriX (Pixmeo SARL, Version 2.5.1., Schweiz).The mean value of three measurements of the same image will be used for analysis. | At baseline and 12 weeks after | 
| Morphological tendon properties, Tendon vascularization level | Equipment Linear ultrasound (7.5 Megahertz (MHz), ESAOTE MyLab 60) Software Doppler Flow Image Analyser version 1.01 Vascularization level of the tendon via Color Doppler (CD) ultrasound CD signals will be estimated through the total number of coloured pixels within the area of interest (3x7 centimeters (cm) with the help of Software Doppler Flow Image Analyser version 1.01 (http://www.gtech.dk). | At baseline and 12 weeks after | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical functional score | Victorian Institute of Sport (VISA) - Achilles (A) questionnaire scores from 0 points to 100 points. | At baseline, 12 weeks and six months after | 
| Interleukin 6 level | Interleukin 6 (IL- 6) detection in the blood plasma is measured in picogram per milliliter (pg/ml) unit. | At baseline and 12 weeks after | 
| Functional tendon properties, Ground contact time | Drop jumps and counter movement jumps on a three dimensional force plate (AMTI, BP400600-2000, 60x40 cm, 1000 Hz) Ground contact time is estimated through ground reaction forces (N or kN). | At baseline and 12 weeks after | 
| Functional tendon properties, Maximum jump height | Drop jumps and counter movement jumps on a three dimensional force plate (AMTI, BP400600-2000, 60x40 cm, 1000 Hz) Maximum jump height is estimated through the vertical impulse / component of the ground reaction force in Newton (N) or Kilo Newton (kN) | At baseline and 12 weeks after | 
| Pain level via Visual Analogue Scale (VAS) | A Visual Analogue Scale (VAS) for pain reaching from 0mm to 100mm as part of the VISA - A questionnaire. | At baseline, 12 weeks and six months after | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Achilles tendon, isometric muscle training, competitive sports, strength training, eccentric exercise, isometric exercise, chronic condition, regeneration, tendon, tendon properties, tendinopathy, tendinosis, intervention, training load, high performance sports