ju Interval Trainer is a free Android application designed to offer an effortless solution to music-driven interval training. The app allows you to choose your preferred music for the workout, warm-up, recovery, and cool-down. It takes care of changing the music according to your training phases, so you don't have to fiddle with your device while working out.

To begin, select playlists or folders on the SD-Card with music for workout and recovery, and enter the duration of the warm-up, workout, recovery, and cool-down. You can save and restore your training sets for future use, and the app automatically remembers the last used training times.

The app features shuffling tracks, fading at transitions, transition sounds, keeping the display on during training, and skipping the currently played song. The app is optimal for Running, Biking, Gymnastics, Ski Gymnastics, Judo, JuJutsu, Weight Lifting, HIIT, Tabata, and all other sorts of sports training.

Although the app is still under development, it is already a great tool for those who want to enhance their workout experience through music. If you encounter any issues or have suggestions for improvement, you can reach out to the developer via email or visit their blog.