Form is half the story. Effort is the other half.

Optical wrist sensors drift during motion. A chest strap reads the electrical signal directly — the same principle clinics use.

Overnight recovery, resting heart rate trend, and recent training load combine into a single readiness number each morning.

Obi Coach adjusts its cues based on which heart-rate zone you’re in — encouragement in zone 2, caution near your ceiling.

When heart rate stops matching effort the way it did earlier in a session, Obi flags rising fatigue before form breaks down.

Stay exactly in the aerobic zone that builds endurance, not above it.

Know whether today calls for a hard session or an easy one, before you begin.

Give a clinician the cardiovascular cost of a rehab session, not just the movement.