The aim of this study is to develop a system to assist in diagnosing individuals with reduced mobility. Specifically, the posture of wheelchair users, which is closely related to their functional status, can be adversely affected by everyday movements and obstacles. To address this, the study proposes a combined monitoring device that tracks real-time users posture and wheelchair movement (distance, orientation, vibrations...) and quantifies the relationship between both. Tests were conducted on various environments, such as smooth floors, ramps, pavements, tramways, and lifts, to establish the relationship between wheelchair motion and user posture. Specific evaluation metrics were used to assess this relationship and the device’s ability to identify it. The results confirm the success of the combined approach, as the system can detect the impact of external agents on user posture. This robust and reliable device helps professionals quantify users functional status and understand the challenges faced by wheelchair users.