RESUMEN
The ubiquitous nature of smartphone ownership, its broad application and usage, along with its interactive delivery of timely feedback are appealing for health-related behavior change interventions via mobile apps. However, users' perspectives about such apps are vital in better bridging the gap between their design intention and effective practical usage. In this vein, a modified technology acceptance model (mTAM) is proposed here, to explain the relationship between users' perspectives when using an AI-based smartphone app for personalized nutrition and healthy living, namely, PROTEIN, and the mTAM constructs toward behavior change in their nutrition and physical activity habits. In particular, online survey data from 85 users of the PROTEIN app within a period of 2 months were subjected to confirmatory factor analysis (CFA) and regression analysis (RA) to reveal the relationship of the mTAM constructs, i.e., perceived usefulness (PU), perceived ease of use (PEoU), perceived novelty (PN), perceived personalization (PP), usage attitude (UA), and usage intention (UI) with the users' behavior change (BC), as expressed via the acceptance/rejection of six related hypotheses (H1-H6), respectively. The resulted CFA-related parameters, i.e., factor loading (FL) with the related p-value, average variance extracted (AVE), and composite reliability (CR), along with the RA results, have shown that all hypotheses H1-H6 can be accepted (p < 0.001). In particular, it was found that, in all cases, FL > 0.5, CR > 0.7, AVE > 0.5, indicating that the items/constructs within the mTAM framework have good convergent validity. Moreover, the adjusted coefficient of determination (R 2) was found within the range of 0.224-0.732, justifying the positive effect of PU, PEoU, PN, and PP on the UA, that in turn positively affects the UI, leading to the BC. Additionally, using a hierarchical RA, a significant change in the prediction of BC from UA when the UI is used as a mediating variable was identified. The explored mTAM framework provides the means for explaining the role of each construct in the functionality of the PROTEIN app as a supportive tool for the users to improve their healthy living by adopting behavior change in their dietary and physical activity habits. The findings herein offer insights and references for formulating new strategies and policies to improve the collaboration among app designers, developers, behavior scientists, nutritionists, physical activity/exercise physiology experts, and marketing experts for app design/development toward behavior change.
RESUMEN
INTRODUCTION: Anecdotal reports suggest that elite road motorcyclists suffer from high core body temperatures and physiological and perceptual strain when competing in hot conditions. METHODS: Four male non-heat-acclimatized elite motorcyclists (3 Superbike, 1 Supersport) had their gastrointestinal temperature, heart rate, and respiratory rate measured and recorded throughout practice, qualifying, and race sessions of an Australian Superbike and Supersport Championship round contested in tropical conditions. Physiological strain was calculated during the sessions, and fluid-balance measures were taken during practice and qualifying. Rider thermal sensation was assessed immediately postsession. RESULTS: Mean ambient temperature and relative humidity were 29.5-30.2°C and 64.5-68.7%, respectively, across the sessions. Gastrointestinal temperature rose from 37.6°C to 37.7°C presession at a median rate of 0.035°C, 0.037°C ,and 0.067°C/min during practice, qualifying, and race sessions to reach medians of 38.9°C, 38.8°C, and 39.1°C postsession, respectively. The peak postsession gastrointestinal temperature was 39.8°C. Median heart rates were ~164, 160, and 177 beats/min during the respective practice, qualifying, and race sessions, contributing to median physiological strain of 5.5, 5.6, and 6.2 across the sessions. Sweat rates were 1.01 and 0.90 L/h during practice and qualifying sessions, while rider thermal sensation was very hot after each session. CONCLUSIONS: This investigation confirms that elite road motorcyclists endure moderate to high physiological strain during practice, qualifying, and race sessions, exhibiting more-rapid rates of body-heat storage, higher core body temperatures, and higher physiological and perceptual strain than their stock-car-racing counterparts when competing in tropical conditions.
