## 2 Theoretical Model and Hypotheses
### Based on the Hypotheses of the Research Framework Model  
In this subsection, this study presents the hypotheses derived from the integrated TAM-DOI framework, linking each conceptual element--relative advantages, compatibility, trialability, gamification, observability, perceived ease of use, and perceived usefulness--to the proposed outcomes of behavioral intention and actual usage. Relative advantages (RA) are defined as the extent to which seniors utilize fitness apps superior to traditional forms of exercise. It reflects the degree to which an innovation is seen as better than its alternatives [29]. A higher perceived relative advantage suggests that the innovation is viewed as a superior choice. Fitness apps offer distinct advantages over traditional exercise models for older adults, such as the ability to work out anytime and anywhere, regardless of weather, time, or equipment availability. Additionally, fitness apps allow users to track their health status and receive professional analyses through automatic data uploads to a cloud database. Seniors also gain access to more expert fitness guidance, all of which only require a smartphone and internet access, thereby reducing costs and expenses [30]. [PERSON] et al. [31] suggested that perceived usefulness (PU) and RA are related but distinct constructs. Furthermore, other studies indicate that RA serves as a prerequisite for PU [32]. Based on this reasoning, the following hypotheses are proposed:  
**H1a:**: _The relative advantages of fitness apps positively influence the perceived ease of use of Asian seniors._  
Figure 1: The research model for assessing acceptance behavior of fitness apps for seniors. **H1b:**: _The relative advantages of fitness apps positively influence the perceived usefulness of Asian seniors._  
Compatibility (CO) refers to \"the degree to which fitness apps can support older adults across the full spectrum of exercise\". It measures the alignment between the innovation and the existing technological and social environments of an individual [29]. The multi-platform development of fitness apps enables Asian seniors to engage in exercise and learning through any electronic device from which they can access their fitness app accounts. For seniors, the primary goal of exercise is to improve strength and health. Furthermore, wearable smart devices can provide personalized recommendations based on the user's physical data and exercise habits. An important aspect of compatibility is its support for socialization, as Asian seniors tend to fear loneliness more than younger populations [33]. Fitness apps facilitate the creation and maintenance of relationships by allowing seniors to share experiences and knowledge with like-minded individuals [34]. These apps help expand social networks while maintaining connections with family and friends in an online fitness-oriented environment. Research has demonstrated significant positive effects of compatibility on perceived ease of use (PEU) and perceived usefulness (PU) [35]. Given this evidence, the following hypotheses are proposed:  
**H2a:**: _The compatibility of fitness apps positively influences the perceived ease of use of Asian seniors._
**H2b:**: _The compatibility of fitness apps positively influences the perceived usefulness of Asian seniors._  
Trialability (TR) refers to the extent to which Asian senior users can experiment with fitness apps on a small scale to test their functionality. For individuals who are less familiar with technology, the opportunity to trial products provides a valuable chance to explore innovations and become more acquainted with their features. Moreover, the initial experience with a product plays a crucial role in shaping an individual's \"first impression\" [36], which subsequently influences continued use. Expectation confirmation occurs when users perceive that their first experience aligns with their expectations [37].