Here is a core trainer that combines with your smartphone to gamify planks and ab workouts. The StealthGO comes with 4 free mobile games. It can be assembled in seconds and lets you use your body movement to control games. You can complete in challenges with friends and track your progress on a real-time worldwide leaderboard.
The StealthGO plank trainer fits any size smartphone. It has 300lbs weight capacity. It has angular arm pads with ergonomic hand grips to keep you in the right position.