In recent years, China's fitness apps have developed rapidly, especially after the COVID-19 outbreak, which has promoted the further expansion of China's mobile fitness application market, leading to changes in people's lifestyles and exercise habits. at-home exercise has become a new trend in sports fitness. While China's current fitness applications demonstrate significant development potential, but they also face various challenges such as insufficient customer stickiness and weak willingness to pay. Solving these problems and promoting the sustainable development of fitness applications is an important task for the fitness app industry in China.

To address tackle these challenges, this study integrates the updated Information System Success Model and proposes a research model to empirically analyze the influencing factors of Chinese users' use and continued use of fitness applications. The collected data is analyzed in depth through structural equation modeling and SmartPLS4.0. The results indicate that the professionalism and playfulness of fitness app information have a significant positive impact on usage. Additionally, professionalism has a significant positive impact on user satisfaction. Furthermore, the study also confirms that the security of fitness application systems has a clear positive effect on usage. Finally, the Responsiveness, personalization, and price value of fitness APP services have significant positive effects on usage. And the timeliness and price value also have a positive influence on user satisfaction.

Through this study, the influence factors of the use and continued use intention of paid features within fitness apps were systematically analyzed. This not only helps businesses to understand the factors that affect users' acceptance of paid features, but also guides the development of paid features for fitness APPs and the improvement of business operations. At the same time, improve the user experience and enhance user stickiness, so that users can continue to pay, thereby creating a benign profit environment for enterprises and expanding corporate revenue.