## 3 Theoretical Framework and Hypotheses
### Perceived Physical Safety  
Perceived physical safety (PPS) is conceptualized as an individual's subjective perceptions of their vulnerability to physical harm or danger in a specific physical environment or situation [39]. In the present study, PPS refers to older adults' perceptions of their body, environment, and health condition safety during performing exercise through IEG. Based on the literature, PPS would positively influence BI in the fields of human-computer interaction, human-robot interaction, occupational exoskeletons, and immersive exergames usage [40; 41; 42; 43]. [PERSON], alt, proposed a concept- attitude towards health. The Domain-Specific Risk-Taking (DOSPERT)scale, including six items of nutrition, smoking and drinking, sleeping, physical inactivity, and hectic lifestyle, was used in the research to extend the UTAUT model [44]. The focus was on long-term health condition awareness among older people instead of the current feeling when performing exergames. Additionally, according to current studies, perceived safety can be described in three conditions: perceived safety of the physical environment, and cognitive and emotional body safety. Usually, perceived safety refers to an assessment of the certain environment and situation where the individual is present. However, the virtual world will lead to two spaces simultaneously during playing IEG. The perceived safety of the physical environment has been reported to be a significant item in the intention to perform physical activities among the older population [45; 46]. Although most published empirical studies often measured perceived safety as a unidimensional construct, perceived safety can be conceptualized as a multidimensional construct composed of both a cognitive component and an emotional component [47]. In the study, older adults' cognitive safety refers to the degree of feeling of injury risk to the physical body and risk of stimuli to their existing health condition (e.g., chronic disease or latent disease). On the other hand, the emotional perceived safety refers to feeling harmony or an anxious inner body while playing IEG among older people. In the study, we hypothesized that older adults may tend to show higher intention to play IEG if they believe it is highly safe.  
**Hypothesis 1 (H1).**_PPS positively influences BI._  
Based on the results of some reviews, it appears that older adults are more likely to perceive insecurity in exercise games using Wii Fit(r) and balance boards compared to other exergames [48]. However, the results of some studies have shown that older adults in a standing position using exercise games on the Wii, Balance Board, or Xbox Kinect report higher perceived usefulness. [PERSON]'s study showed that the adventure-fit game genre through Kinect is preferable to other games for older people [49]. [PERSON] and [PERSON] used Dance Dance evolution (DDR) in which older females had to be more careful to keep up with the pace while following the arrow, and the response demonstrated the feelings of usefulness and high-performance expectation of their health [50]. Therefore, in this study, we hypothesized that older adults may tend to show lower performance expectancy of IEG if they believe it is highly safe.  
**Hypothesis 2 (H2).**_PPS negatively influences PE._