A big issue with some Big Tech health cloud services like Apple, Google, etc is you can’t get your data out easily to perform your own analytics, or use them if you decide to leave that platform. Apple Health cannot be viewed or analysed on a Linux desktop at all.
These tools help monitor exercise offline from your devices, either through direct link, or importing of data.
Jogger is for Linux computers or phones to track running and other workouts.
Golden Cheetah is a really powerful offline analysis tool that connect with indoor trainers and cycling equipment such as cycling computers and power meters to import data. In addition, it can connect to cloud services such as Strava. It shows many stats that I don’t even understand, but seems ideal for analysing cycling, swimming, etc and asks for data such as wheel sizes, swimming pool lengths, and so on. It will also track nutrition and body measurement data, and it runs on Windows, Linux and macOS.
MyTourbook is software which lets you visualize and analyse tours which are recorded by a GPS device, bike- or exercise computer and ergometer.
See https://www.linuxlinks.com/best-free-open-source-alternatives-apple-health