Association between shoulder external rotation strength and real-world arm use in patients with mild post-stroke hemiparesis: a cross-sectional study.

[Purpose] This cross-sectional study investigated the association between shoulder external rotation strength and real-world arm use in patients with mild post-stroke hemiparesis. [Participants and Methods] Seventeen participants with ≥Brunnstrom stage IV and active shoulder flexion ≥110 degrees were assessed. External rotation strength was measured using a hand-held dynamometer. Real-world arm use was evaluated using the Motor Activity Log. [Results] External rotation strength was associated with Motor Activity Log scores and grip strength. Participants with movement-induced shoulder pain demonstrated lower external rotation strength compared with those without pain. [Conclusion] Reduced shoulder external rotation strength may contribute to decreased real-world arm use in mild hemiparesis.