10+ similar apps compared and reviewed
Whether you want more options like 4x4 HIIT or a completely different take on the same concept, our curated list of 10+ similar apps has you covered. Updated for 2026 with the latest ratings and comparisons.
This app guides you through the Norwegian 4x4 VO2max interval training protocol using your Bluetooth heart rate monitor. It provides real-time audio cues to keep you in your target heart rate zones during work and rest intervals.
This app guides you through a structured interval workout, calculating your target heart rate zones and providing real-time coaching. It features a simple warm-up, four intense 4-minute intervals with recovery periods, and a cool-down, all managed by an integrated timer. Track your progress and sync data with Apple Health.
