If You want have flat stomach You must do suitable exercises to achieve the best effect. Thanks this training You achieve strenght core. You have to do 7 moves- You do 2 circuits and You need have only 15 minutes for all training. These exercies are: Mountain climbers 20 times, Single leg bird dog 10 times, Single leg deadlift 10 times, Plank shoulder taps 20 times. Bicycle crunches 20 times, Crab twists 10 times, Reverse burpees 10 times.