fitlake puts all my training data in one place: gym workouts, runs, MMA sessions, and sleep and heart rate from my watch.

From this data it builds an athlete model based on known methods from sports science:

readiness: a score every morning from heart rate variability, resting heart rate, sleep and breathing
session load: Banister TRIMP from heart rate, and Foster session RPE
weekly load: Foster monotony and strain, and the last 7 days against the last 28
strength: estimated one-rep max for each lift (Epley and Brzycki formulas) and how fast it grows
muscle balance: hard sets for each muscle group per week
running: VO2max, easy and hard runs split by heart rate (Seiler), heart rate recovery

I built it when I started doing gym, running and MMA at the same time. I needed to balance the load, see my progress and avoid overtraining.

fitlake is private. It reads health data from Google Health, and Google allows this for other people only after a long security review of the app. So I have not decided yet how to share it.