This exercise, which is preferably performed in the deep-end with a pool noodle, in standing position, can be performed in the shallow-end as well. If performed regularly and in combination with other abdominal exercises, you can expect some good results.
Starting Position In the deep-end, put a noodle under your arms (or use any other floating device) and float upright. Rest your hands and your forearms on the noodle and relax your shoulders. Keep your legs straight and hip-width apart.