The Workout app, one of the most popular apps on the Apple Watch, has been updated to provide richer metrics for measuring performance, as well as new training experiences to help users reach their fitness goals.

The familiar in-session display now uses the digital crown to cycle between easy-to-read workout views, so users can see key metrics for different training styles.

Heart rate zones, using personalized health data, can be used to monitor the intensity of a workout.

For interval training, the Workout app introduces custom workouts, which can be used to create a structured workout that includes work and recovery intervals.

New alerts including speed, power, heart rate and cadence can be added to guide users throughout their workouts.

For triathletes and duathletes, the Workout app now supports a new multisport workout type that automatically switches between any sequence of swimming, biking and running workouts, using motion sensors to recognize movement patterns.

The iPhone's fitness app also features a redesigned summary page that provides additional details, including interactive charts, for a more precise analysis of all workouts.