Reduced shoulder mobility limits upper-limb function and the performance of activities of daily living across a wide range of conditions. Wearable exosuits have shown promise in assisting arm elevation, reducing muscle effort, and supporting functional movements; however, comfort is rarely prioritized as an explicit design objective, despite it strongly affects real-life, long-term usage. This study presents a redesigned soft shoulder exosuit (Soft Shoulder v2) developed to address comfort-related limitations identified in our previous version, while preserving assistive performance. In parallel, assistance was also improved, shifting from the coronal plane to the sagittal plane to better support functionally relevant hand positioning. A controlled comparison between the previous (v1) and redesigned (v2) modules was conducted in eight healthy participants, who performed static holding, dynamic lifting, and a functional pick and place task. Muscle activity, kinematics, and user-reported outcomes were assessed. Both versions increased endurance time, reduced deltoid activation, and preserved transparency during unpowered shoulder elevation. However, the difference between them emerged most clearly during functional tasks and comfort evaluation. The redesigned module facilitated forward arm positioning and increased transverse plane mobility by up to 30 deg, without increasing muscular demand. User-reported outcomes further indicated a substantial improvement in wearability, with markedly lower perceived pressure and higher ratings in effectiveness, ease of use, and comfort compared to the previous design. Taken together, these findings show that targeted, user-centered design refinements can improve comfort and functional interaction without compromising assistive performance, advancing the development of soft exosuits suitable for prolonged and daily use.

翻译：肩关节活动度降低会限制上肢功能，并在多种疾病状态下影响日常生活活动的执行。可穿戴外骨骼服在辅助手臂抬升、降低肌肉负荷及支持功能性运动方面展现出潜力；然而，舒适性很少被明确列为设计目标，尽管其强烈影响实际长期使用。本研究提出一种重新设计的软性肩部外骨骼服（Soft Shoulder v2），旨在解决先前版本中发现的与舒适性相关的局限，同时保持辅助性能。此外，辅助性能亦得到改进，将辅助平面从冠状面转向矢状面，以更好地支持功能相关的手部定位。我们在八名健康参与者中对先前版本（v1）与重新设计版本（v2）进行了对照比较，参与者执行了静态保持、动态抬升及功能性拾取放置任务。评估内容包括肌肉活动、运动学数据及用户自评结果。两个版本均延长了耐受时间，降低了三角肌激活水平，并在无动力肩部抬升时保持了透明度。然而，两者差异在功能性任务和舒适性评估中最为明显。重新设计的模块促进了手臂前向定位，并将水平面活动度提升高达30度，且未增加肌肉负荷。用户自评结果进一步表明穿戴性得到显著改善，与先前设计相比，感知压力显著降低，在有效性、易用性和舒适性方面的评分明显更高。综上所述，这些发现表明，以用户为中心的针对性设计改进能够在保持辅助性能的同时，提升舒适性与功能交互性，从而推动适用于长期日常使用的软性外骨骼服的发展。