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.
This research project was funded by means of the "Bundesinstitut für Sportwissenschaft" based on a resolution of the German Federal Parliament.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
45
Humboldt Universität zu Berlin, Institut für Bewegungswissenschaften, Department Movement Sciences
Berlin, Germany
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.
Time frame: 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)
Time frame: 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)
Time frame: 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.
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Time frame: 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).
Time frame: At baseline and 12 weeks after
Clinical functional score
Victorian Institute of Sport (VISA) - Achilles (A) questionnaire scores from 0 points to 100 points.
Time frame: 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.
Time frame: 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).
Time frame: 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)
Time frame: 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.
Time frame: At baseline, 12 weeks and six months after