Compensation Strategies in Post-Stroke Individuals: Insights from Upper Body Kinematics Analysis Based on Inertial Sensors

Highlights: What are the main findings? The use of inertial measurement units (IMUs) during the Box and Block Test enabled detailed kinematic analysis and the identification of typical compensation strategies in post-stroke individuals. Overuse of the wrist, shoulder, and trunk was quantified, with 88% of participants showing compensation at the wrist and trunk, and 68% at the shoulder. What is the implication of the main finding? IMUs provide a simple, eco-friendly, and effective tool for objectively assessing movement quality in clinical settings. Detecting and quantifying compensation supports the development of personalized rehabilitation approaches and contributes to optimizing functional recovery after stroke. Background: One of the main goals of rehabilitation after stroke is the restoration of motor function. Understanding movement patterns and compensatory strategies is essential to optimize therapy. This study analyzes upper limb kinematics during the Box and Block Test (BBT) to identify and quantify typical post-stroke compensation strategies. Methods: Thirty-one sub-acute stroke participants and thirty-one healthy controls were included. Kinematic data were collected using a 7-IMU system. Joint angles were analyzed with MATLAB R2023a, and 3D trajectories were reconstructed from calibrated quaternions and anthropometric data. Group differences were assessed with the Mann–Whitney test. Compensation strategies were quantified in percentage terms relative to healthy subjects. Results: Significant intergroup differences were observed in mean joint angles and ranges of motion. On the paretic side, participants overused the wrist and shoulder to compensate for reduced elbow and trunk activity. Similar overuse was also observed on the unaffected side. Quantification showed that 83.9% and 80.6% compensate, respectively, with wrist and trunk and 67.7% with the shoulder. Conclusions: Using IMUs during the BBT, this study identified specific compensation strategies that may hinder recovery. It also contributed to developing a quantification scale, supporting more personalized rehabilitation and improved quality of life.