Pilot study of effective methods for measuring and stretching for pectoral muscle tightness in breast cancer patients

[Purpose] To evaluate differences in pectoral muscle tightness according to arm abduction angle and to determine the best arm abduction angle for stretching of pectoral muscle tightness in breast cancer patients. [Subjects and Methods] Horizontal abduction differences of shoulders were measured bilaterally by arm abduction to 45°, 90°, and 135° to determine the best arm abduction angle for measuring pectoral muscle tightness. Thirty-two patients were divided into three pectoral muscle stretching groups (A: 45°, B: 90°, and C: 135°). We measured the shoulder range of motion, scores of the Disabilities of the Arm, Shoulder, and Hand, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire and the Breast Module, and pain levels (using a visual analog scale) before and after therapy. [Results] The differences in degree of horizontal abduction between shoulders were significantly larger for arm abduction to 90° and 135° than that to 45°. Groups B and C showed greater improvements in horizontal abduction limitations than group A. [Conclusion] Horizontal abduction differences between shoulders are prominent when arms are abducted to 90° and 135°. The appropriate arm abduction angle for measuring horizontal abduction and effective stretching of pectoral muscle tightness may be >90°.