IMU-Based Assessment of Arm Movement in Breast Cancer Survivors: An Exploratory Study

Breast cancer (BC), despite its high survival rate, can cause significant functional sequelae in the scapulohumeral joint after surgery. This study evaluated angular velocity during a lateral reach test, comparing the operated arm with the non-operated arm as a possible indicator of functional asymmetry. This study employed an observational, comparative, cross-sectional design. Twenty-two women voluntarily participated in the study. The anthropometric characteristics were as follows: mean age, 55.95 ± 6.34 years; height, 1.63 ± 0.06 m; body weight, 65.37 ± 11.10 kg; and BMI, 24.73 ± 3.60 kg/m2. The participants, who were survivors of breast cancer and had undergone surgery on only one arm, regularly performed physical activity in the Department of Exercise, Education, and Cancer at the University of Murcia, BC. A lateral opening test was performed, measuring the angular velocity in both arms during 15 repetitions using the WIMU PRO™ inertial device. Results showed no significant main effects for arm (p = 0.369) or surgery side (p = 0.587) but a significant interaction (F = 29.44, p = 0.001), with lower velocity in the operated arm both for right-side surgery (right: 100.4 ± 31.1 vs. left: 111.7 ± 32.0 °/s) and left-side surgery (left: 92.1 ± 22.3 vs. right: 100.2 ± 20.2 °/s). Effect sizes were small to moderate (Hedges’ g = 0.35–0.36). This difference may suggest the presence of postoperative functional asymmetries, which may inform future research on therapeutic exercise approaches, though direct clinical applications cannot yet be established. These preliminary findings highlight the feasibility of using inertial devices to assess postoperative functional asymmetry in breast cancer survivors.