Exercise balls may not look like the kind of workout that would help you burn fat or lose weight, but a new study suggests they could be just as effective.

The researchers, from the University of Colorado-Denver, tested 675 women who were randomly assigned to one of four groups: exercise ball workout (which included aerobic and anaerobic workouts); strength training and strength training plus cardio workouts (both aerobic and cardio workouts); exercise ball (which consisted of aerobic and resistance training); and a control group.

The researchers compared the results between groups on a range of measures, including body composition, waist circumference, heart rate, and the ratio of fat-free mass to lean mass.

The results showed that exercise ball programs were significantly better at reducing the percentage of body fat and body mass and the percentage change in fat-to-lean mass compared to strength training programs, according to a press release from the study.

“It seems that strength training alone does not have a significant impact on body composition and the change in body fat percentage,” lead researcher, University of Denver School of Medicine researcher and associate professor of medicine Dr. Thomas T. McKeown, said in a press conference.

“The exercise ball was an intervention that was significantly better than either resistance training or aerobic training.”

The study’s authors also noted that the exercise ball training program, compared to a strength training program or an aerobic training program did not affect muscle mass, strength or endurance performance.

“It’s not the number of repetitions that matters, it’s the number and intensity that matters,” Dr. McLeown said.

“We’re trying to get the most bang for our buck.”