Riven

Find your muscle failure—measured from your wrist, via Apple Watch.

Riven Instruments builds a wrist‑only fitness platform that automatically detects exercises, counts reps, measures velocity and heart rate, and determines true muscle failure using the Apple Watch. The app runs entirely on watchOS, requiring no straps, clips, or external hardware. By analyzing motion data hundreds of times per second, it logs each set, provides failure scores, and delivers detailed, muscle‑group‑specific insights so lifters can train to the optimal point of fatigue. Riven’s companion iPhone app aggregates the data, tracks progress over weeks, and helps users eliminate guesswork and improve strength gains.