Updated December 16, 2014.

The Vertical Knee Raise, often called the Captain's Chair exercise, came in second on the list of best exercises for the rectus abdominus. This is the conclusion of a study at San Diego State University that compared 13 common abdominal exercises in order to find which ones really strengthen the abs. Each exercise was ranked for muscle stimulation (measured with EMG) in the rectus abdominus and the internal and external obliques.

The captain's chair exercise was one of the few ab exercises on the "most effective" list that requires gym equipment. You will generally find a vertical knee raise machine in health clubs, or shop for one designed for home use.

Vertical Knee Raise Machine

How to Do the Captain's Chair Exercise

• Start with legs dangling and slowly lift your knees in toward your chest.
• The motion should be controlled and deliberate as you bring your knees up and return them back to the starting position.

Question:How Does the Captain's Chair Exercise Work the Abdominals?

Also See

• The Best and Worst Ab Exercises
• More Great Ab Exercises to Try