## 1 Introduction
### LSAD-Related Work  
In the treatment of back pain, there is now a greater emphasis on self-management, physical and psychological therapies, and certain forms of complementary medicine, with less emphasis on medication and surgical treatments [15]. For example, an American guideline on the assessment and treatment of back pain indicates a reduced reliance on pharmacological treatments, and recommends non-pharmacological therapies as the preferred treatment option [16]. Among these, LSAD is often used as an adjunctive approach by patients with back pain. In most studies, LSAD is considered to improve the pain condition of patients with back pain. Some studies have clearly elucidated the benefits and functions of these types of assistive devices:  
* Limit overall trunk range of motion [17; 18];
* Ameliorate disc stress by increasing abdominal pressure [19; 20];
* Enhance proprioception and stability, improving posture through applied pressure [21; 22];
* Have no negative impact on muscle strength or lumbar spine function [23; 24];
* Reduce lumbar muscle fatigue [25];
* Enhance torso mobility for daily activities [26; 27]. In summary, LSAD is designed to provide additional lumbar support and facilitate lumbar rehabilitation. Prior studies have predominantly examined the efficacy [27; 28; 29] and operational mechanisms [23; 24; 30] of LSAD, leaving patient-experience aspects relatively unexplored. However, a positive attitude (i.e., the benefits brought by the device) has become a decisive factor in patients' use of such devices and is considered to some extent to offset users' adverse experiences [31]. Nevertheless, it is essential to consider that these adverse experiences may not be entirely offset. Instead, they may represent a compromise that users reluctantly accept to achieve favorable rehabilitation outcomes. Therefore, understanding users' experiences in product design (in this study, LSAD) and involving users in the process are considered crucial [32; 33; 34]. This includes understanding and comprehending users' physiological, psychological, and environmental factors, needs, and priorities [35; 36]. This is beneficial for reducing barriers to the use of assistive devices [37] and improving compliance during the rehabilitation process. A recent study based on a survey of preferences and satisfaction among 258 elderly individuals found that users prefer integrated products, minimalist designs, and LSAD that provide sufficient support [38]. Another study surveyed 40 patients with lumbar disc herniation, revealing that the period of their usage of LSAD did not exceed one year [39]. Dissatisfaction primarily stemmed from fabric, mobility, and design, with discomfort  
Figure 1: Popular product examples of flexible, semi-rigid, and rigid LSAD [14]. being the most common complaint [39]. [PERSON] and [PERSON]'s study [40] indicated that size is a factor leading to a worse wearing experience for obese users with commercially available LSAD. The existing literature provides valuable supplementary information for research related to the user experience of LSAD, although there is still a certain degree of ambiguity regarding the usage and patient-wearing experience of these devices, and we have not yet fully understood the actual usage scenarios of these devices or patient satisfaction. Understanding how patients use LSAD and their satisfaction are crucial for improving LSAD [41]. Patient satisfaction not only relates to their adherence to rehabilitation plans but can also influence the effectiveness of rehabilitation. Given the widespread use of LSAD in lower-back pain management, there is a relatively limited amount of research on the user experience of LSAD. Therefore, more research on the wearing experience of LSAD is still needed to provide relevant researchers with more detailed information during the patient rehabilitation phase. This study aims to gain a comprehensive understanding of how patients with lower-back pain use LSAD, patient satisfaction, and the overall wearing experience.