A free program for Android, by Martin Machata.

High intensity interval training, sometimes known as HIIT, is a type of cardio exercise performed in quick, intense bursts with the goal of maximizing athletic performance while depriving the muscles of oxygen.

If you want to increase strength and muscle endurance or reduce weight, HIIT is a terrific activity to incorporate into your program.

An application for high-intensity interval training called Tabata Timer is free.

Here are some of its features: