Design and Implementation of a Fitness Application Based on HarmonyOS

With the rapid development of mobile technology, fitness applications based on intelligent operating systems have become an important tool for health management. This article designs and implements a fitness app based on HarmonyOS to provide users with personalized activity records, training plans, and data analysis functions. The system adopts object-oriented system analysis and design methods, and its main functions include user management, sports data recording, training plan formulation, social interaction, etc. The database is designed with a relational model to support the storage and management of user information, exercise records, training plans and other data. This article also discusses the application potential of HarmonyOS in the field of mobile health, and analyzes the technical implementation details of the system, including the development environment, technology stack, and implementation of key functional modules. Through system testing, its functional integrity and performance stability were verified. This study provides a reference for the development of fitness applications based on HarmonyOS, and provides theoretical support for further optimization of mobile health services.