Laura Peeters

The trunk in Duchenne Muscular Dystrophy | 77 4 Outcome measures Participant characteristics The following participant characteristics were noted based on self-reports: age, weight, height, arm preference, age of diagnosis (if applicable), use of corticosteroids, wheelchair confinement, pain in upper body at time of participation and occurrence of scoliosis. Sitting height was measured and, for DMD patients, the Vignos lower extremity scale [12] and Brooke upper extremity scale [13] were used for clinical assessment of leg and arm function, respectively. Three dimensional motion analysis We used the same data acquisition and analysis as employed in a previous study with healthy children [10]. An optical motion capture system (Vicon, Oxford, UK) was used to record 25 single reflective markers, which were placed on the skin to define positions and orientations of the head, trunk, pelvis and both arms during task performance. The markers divided the trunk initially into four segments (upper thoracic, lower thoracic, upper lumbar and lower lumbar), because the trunk cannot be seen as rigid segment [10]. However to make the data more concise, we decided to report here the trunk movement as one segment (i.e. summation of the trunk and pelvis segment angles). Distribution of movement patterns over the individual trunk segments was essentially the same among HC and DMD. All kinematics data were filtered with a bi-directional 4 th order Butterworth low- pass filter (cutoff frequency of 6 Hz). Trunk joint angles are expressed relative to the global coordinate system, and are described in all three movement directions: flexion-extension (i.e. sagittal plane), lateral bending (i.e. frontal plane) and axial rotation (i.e. transversal plane). Maximum trunk joint angles in all three movement directions were determined when performing the active range of motion (ROM) tasks for trunk. For the reaching tasks and daily tasks, the trunk ROM between the start and end of the task was determined. Start and end of a task were defined as the time where the velocity of the wrist exceeded/got below 5% of its peak velocity. Direction of the movement was defined for all reaching tasks by subtracting the trunk joint angle at the time of touching the reference frame, from the joint angle at the start. This defined whether the movement was in a positive or negative direction (i.e. flexion or extension, or towards dominant or non-dominant side). Towards dominant side reflects the side of the hand used to perform the tasks.