Don't fall behind is an exergame app that communicates in real time with the wearable activity tracker (Apple Watch and TI Sensortag) and uses the data received from its inertial measurement unit as input to the game. You can play games in three exercises: running, cycling or skipping to control the action of the game character in real time. For running and cycling, we recommend installing the phone in front of the treadmill/bicycle during exercise. For skipping, we recommend projecting the phone screen onto the TV to make sure you can easily see the screen while jumping. The story of the game is based on a bird that is behind the flock of birds. The goal is to regroup the birds before the time runs out and before the flock reaches their destination. There are also physical and environmental parameters that can affect the movement behavior of birds and flocks, find it during exercise! The game has a task-based structure and a point-based system. After reaching the task, you can unlock a higher level. Including the achievement system, plus the multiplayer game mode brings the leaderboards and challenge boxes, allowing players to compete with each other. Apple Watch or TI Sensortag needs to actually interact with this game.