|- candidate number||7927|
|- NTR Number||NTR2284|
|- ISRCTN||ISRCTN wordt niet meer aangevraagd.|
|- Date ISRCTN created|
|- date ISRCTN requested|
|- Date Registered NTR||12-apr-2010|
|- Secondary IDs||40-00703-98-8564 ZonMW|
|- Public Title||Muscle activation patterns of the supraspinatus and deltoid muscle in abduction of the arm: Motion generator or GH (de)stabilizator?
|- Scientific Title||Muscle activation patterns of the supraspinatus and deltoid muscle in abduction of the arm: Motion generator or GH (de)stabilizator?
|- hypothesis||We hypothesize that, with increased arm abduction moment loading with a constant exerted abduction force, primary arm moment generators (deltoid muscle) will have a greater increase in activation (EMG) as compared to primary arm/glenohumeral stabilizators (supraspinate muscle).|
|- Healt Condition(s) or Problem(s) studied||Healthy subjects, Rotator cuff|
|- Inclusion criteria||1. Age: between 18 and 60 y.o.;|
2. No history of shoulder complaints;
3. No current complaints of the shoulder.
|- Exclusion criteria||1. No signed informed consent;|
2. Pace-maker or other electronic implants.
|- mec approval received||yes|
|- multicenter trial||no|
|- Type||Single arm|
|- planned startdate ||25-feb-2010|
|- planned closingdate||25-feb-2011|
|- Target number of participants||23|
|- Interventions||Subjects will be seated, having their dominant arm fixed in a splint. Next, subjects will have to exert isometric forces in directions perpendicular to the long axis of the humerus, using visual feedback. |
In a second session, the same approach will be applied, with the same exerted arm force. However, in the second session the exerted force will be applied at a point nearer to th GH-joint.
In this manner, subjects will participate in 2 sessions of measurements using the same exerted force. However, subjects will be subjected to 2 separate amounts of arm moment loading.
During the isometric force tasks, EMG will be recorded using surface electrodes.
|- Primary outcome||External force controlled Electromyography (EMG).|
To measure activation of individual shoulder muscles (in particular: deltoids, supraspinate, infraspinate, pectoralis major, upper and lower trapezius, latissimus dorsi and teres major) and analyze for relative changes in activation of rotator cuff and deltoid muscles with increased arm moment loading.
Conditions: Arm against an external force in 24 directions (humerus fixed in splint, constant exerted abduction force), 2 moment arms (~4 cm and ~29 cm from the glenohumeral joint).
Outcome: Average filtered EMG value (rEMG), principal Action (PA), Activation Ratio (AR) and Max Voluntary Force (MVF), relative change in deltoid and supraspinate activation (rEMG) expressed in percentages.
|- Secondary outcome||3D-Motion tracking of the scapular position during arm force task with the humerus in a fixed position. To record 3D kinematics of the scapula with a motion tracking system for analyzing the eventual change in scapular position as a result from changes in muscle activations when altering moment loading (with a constant force). |
Conditions: Arm against an external force (humerus fixed in a splint, constant exerted force), 2 moment arms (~4 cm and ~29 cm from the glenohumeral joint).
Outcome: 3D scapular positions (scapular posterior tilting, external rotation, and lateral rotation as described in literature) with altering moments and muscle activations.
|- Timepoints||Intake and measurements at 1 timepoint.|
|- Trial web site||N/A|
|- status||open: patient inclusion|
|- CONTACT FOR PUBLIC QUERIES||MD P.B. Witte, de|
|- CONTACT for SCIENTIFIC QUERIES||MD P.B. Witte, de|
|- Sponsor/Initiator ||Leiden University Medical Center (LUMC)|
(Source(s) of Monetary or Material Support)
|ZON-MW, The Netherlands Organization for Health Research and Development, Reumafonds|
|- Brief summary||It is generally alleged that mobility in the glenohumeral joint is generated by muscles with relative large force moment arms, while stability in the glenohumeral joint is predominantly guarantied for by muscles close to the joint with relatively small moment arms: the rotator cuff muscles. Consequently, there is a lack of glenohumeral stability in patients with rotator cuff tears, with subsequent relative cranial translation of the humerus and pain. For abduction of the arm, the deltoid would be the main moment generator, with the rotator cuff muscles providing glenohumeral stability. Nevertheless, these beliefs have never been assessed by biomechanical analyses.
Arm motion (e.g. arm muscle forces and moments) and scapular position directly correlate, but it is not clear whether scapulohumoral rhythm has an essential and active role in facilitating arm motions, or if it is simply the result of muscle activations and intended arm motions. The cooperation of muscle activation patterns and scapular position needs to be studied, because distorted scapulohumoral or scapulo-thoracal rhythm is related to subacromial pathologies. |
|- Main changes (audit trail)|
|- RECORD||12-apr-2010 - 22-apr-2010|