Hi,
I have lot of experience for creating app . I can make your app in flutter for both platform. For specific fitness app have not develop yet. But can develop as well good then ever.
This is Vikas, an Android and Flutter developer having 8 years of work experience with mobile app development and also some experience with PHP for APIs and backend as SQL for server data.
Skills: Android, Flutter, Php, java, kotlin, Asp.net, Mysql, SQLite, SQL, Sqflite, JSON, Firebase