Even with all of the complex nautilus machines, such as the Bo Flex, available for thousands of dollars, more and more people are investing in the most simplistic of exercise equipment. For around $20 people are incorporating fitness balls into their workout regime.

Exercise balls were originally used by physical therapists about 30 years ago and are now one of the most popular exercise equipment pieces in the fitness industry, according to BodyTrends.com.

These balls are used at the Student Recreation Center as well. Since 1999, exercise classes such as Abs 30, Sculpt 45 and many cardiovascular workout classes such as kickboxing and step areobics use the fitness ball as part of the routine.

At these classes, trained fitness instructors show participants first hand how to use the exercise balls correctly.

So what are they good for? According to Liz Applegate, fitness expert and the author of “Bounce Your Body Beautiful,” a lot.

Applegate says that exercises done with the fitness ball help to engage muscles such as abs, legs, back and gluteus more so than exercises that do not include them. Fitness balls are used to tone the thighs, lower back, abdonimals, including upper, lower and obliques, and arms.

Cathy Swick, Director of the Group Exercise Programs, agrees. “The balls make the exercises more effective because it’s an unbalanced surface.”

It’s the balancing on the fitness ball that makes the exercises so effective.

“The fitness ball engages a core strength needed to balance on it,” Swick said.

As far as incorporating the fitness ball into an at-home routine, some people may need to get used to using the fitness ball. Applegate suggests people get acquainted with the ball first by sitting or kneeling on it.

When purchasing a fitness ball for at-home use, many, such as the ResistaBall, offer workout videos to purchase as well. As with any exercise program, however, toning is never enough. Cardiovascular exercise, such as the classes taught at the University’s Student Recreation Center is also important in maintaining a healthy, well-rounded exercise routine.