Core strength may be tiring, but it is very useful. A week will definitely work, depending on whether you can stick to it. Flat support is like push-ups, but it is elbow support, and the waist should be straight for one minute. There are also side plate supports, both on the left and right sides, for one minute, and finally you lie down with your shoulders and thighs as high as possible from the ground. This is also a minute. Four action cycles, three or four groups.