How to: Roll up a towel and place it under the bottom third of your shoulder blades, then like back with knees bent to 90 degrees, feet flat (a). (dailyburn.com)
A fifth - year senior, he had used his time wisely while out with a knee injury his sophomore year. (si.com)
It is, therefore, important to make sure that your belly is ready before you start exercising by laying flat on your back with your knees bent. (newkidscenter.com)