Muscle load in reaching movements performed by a wheelchair user: a case study

The aim of this study was to analyse the load on the shoulder muscles during reaching movements that are specific to wheelchair users in relation to the risk of impingement.

Three activities of daily living were performed: putting a book on a shelf in front and at the side and putting a pack of water bottles on a table. The AnyBody shoulder model was used to calculate the activity and forces of the shoulder muscles.

Handling the pack of bottles caused the highest forces in the deltoideus, trapezius, serratus anterior and rotator cuff muscles. For handling the book, the highest forces were found in the deltoideus (scapular part) and the serratus anterior, especially during the put phase.

Handling heavy objects such as a pack of bottles or a wheelchair produces high forces on the rotator cuff muscles and can lead to early fatigue. Therefore, these activities seem to be associated with a high risk of developing impingement syndrome. Implications for Rehabilitation In a single patient, this study demonstrates that the load on the rotator cuff is high during reaching movements. Handling a pack of water bottles, which resembles wheelchair handling, represents an activity associated with a high risk of developing impingement syndrome. Shoulder muscles must be trained in a balanced way to provide stabilization at the shoulder joint and prevent fatigue.