In this freestyle swimming drill you learn to balance while rolling between the head up and head down positions. Additionally, you learn get a breath of fresh air by rolling the body instead of lifting the head.
This drill belongs to an older sequence of swimming drills to learn the freestyle stroke. Please consult the Learn How To Swim The Freestyle Stroke article to learn the current sequence of swimming drills.
While you roll between the body up and body down positions, you will need to continuously change how you lean on your upper body to keep your hips and legs up. This is a valuable skill to posses as it lets you balance in any position in your front crawl technique.
This was the last of the freestyle stroke drills for balance. Your legs and hips should now stay up without any effort while you swim the freestyle. If not, review the balance drills.