Reaching Motion by the Elderly During Functional Activities. A Comparison Beween a Healthy Control Group and Patients With a Reverse Shoulder Arthroplasty

This study aims to investigate how elderly people (60 years and older) without shoulder pain and patients with a reverse shoulder arthroplasty (60 years and older) perform functional reaching movements. Using IMUs (Inertial Measurement Units), the investigators want to look at mode of execution, relational positions of hand, elbow and shoulder in space, in relation to the trunk and each other, and any compensatory movements made by patients with a reverse shoulder arthroplasty.

At the time of testing, participants will first complete a series of questionnaires. These questionnaires will provide information about the daily functioning of all participants. The participants' shoulder strength will also be measured.

After applying the IMUs, the participant will first perform a maximal movement (active for participant) in 4 directions (forward and lateral lifting of arm, hand-to-neck , hand-to-back). Then the researcher will perform the same movements with the participant's arm (passive for participant). This will allow measurement of the maximum active and passive mobility of the shoulder. Next, the participant will be asked to place and take back a number of different objects (both in terms of size and weight) at predetermined heights.

The participants without shoulder pain will be tested once, the participants with a reverse shoulder arthroplasty we want to test 4 times. The participants without shoulder pain will be assigned to the control group. The participants with a reverse shoulder arthroplasty we want to test 4 times to monitor not only their movement pattern, but also any changes in this pattern .

The questionnaires, strength measurement and requested movements will be the same for both groups.