A new study suggests that women with chronic issues with their body-image are more likely to benefit from an exercise class where the instructor emphasizes the health benefits of the workout over improved appearance, even if those women chose the class in hopes of improving their physique.

Researchers studied nearly 100 college-aged women who had social physique anxiety - a disorder in which someone chronically worries that others are critiquing his or her body.

"Women who have this disorder usually are interested in exercise to improve their appearance, but an instructor who emphasizes physique during a workout may deter such students from coming back," said Brian Focht, a study co-author and an assistant professor of health behavior and health promotion at Ohio State University.

Women in the study reported that they enjoyed a step-aerobics class more when the instructor focused on the health-related aspects of the workout, telling them how exercise will make them more fit.

These same women were more likely to say that they would try a similar class in the future, compared to the women who were taught by an instructor who emphasized appearance by making comments about how the exercise would tone their legs or other body parts.

"We want to design the most beneficial exercise programs for different groups of people, and understanding how people respond to different approaches to exercise is key to doing so," Focht said. "We chose a very specific sample of women that we thought would be sensitive to the comments made by instructors."

The study's results appear in a recent issue of the journal Psychology of Sport and Exercise. Focht conducted the study with Thomas Raedeke and Donna Scales, both researchers at East Carolina University, in Greenville, N.C.

All women enrolled in a required physical activity course at the university answered a questionnaire on exercise and body image. A woman's answers indicated if she had social physique anxiety. Only those women with the disorder were asked to participate in the study.

The average age of the 99 participants was 19. Their average body mass index was 24.7, which is within the ideal range for body size. The women reported that they worked out at moderate or vigorous intensity about 3.3 times a week.

The women participated in one of four 45-minute step-aerobics classes. The same instructor taught each class, although she emphasized health over appearance in two of the classes. In the other two classes, she emphasized appearance over health. One class in each scenario included a mirror.

"There is a fair amount of research that suggests that mirrors in a workout room can negatively affect how someone feels, particularly a woman who is concerned about her physical appearance," Focht said.

In the classes that emphasized health over appearance, the instructor wore a loose-fitting t-shirt and gym shorts. She also sprinkled health-oriented comments throughout the session, such as "Work it, let's get fit and healthy!"

She wore tight-fitting aerobics attire in the appearance-oriented classes. She made comments throughout the classes that drew attention to appearance, such as "Stand tall, you'll look five pounds lighter" or "Work it, let's get your legs toned so they look good!"

About five to 10 minutes after class each woman filled out the Exercise-Induced Feeling Inventory. This questionnaire measures how someone feels after exercising, whether revitalized, physically exhausted, tranquil, etc. The women also answered questions on the Physical Activity Enjoyment Scale, whereby each woman rated how much she enjoyed the class, and whether she would likely participate in a similar class in the future.

The results of both surveys suggested that the instructor's leadership style directly affected the student's attitudes toward the class. The women in the health-oriented class reported that they felt more engaged in the workout as well as revitalized and less exhausted after class than did the women in the appearance-oriented classes.

The participants in the health-oriented classes reported that they also enjoyed the workout more and would be more likely to take a similar class in the future.

Focht and his colleagues were surprised to find that the presence of mirrors in the exercise room didn't influence how the women felt during class.

"We expected the mirrors to have some effect on these women, but that wasn't the case," he said. "It was the instructor's leadership style that had a direct effect on the students' attitudes."

Focht also said that fitness instructors don't need to throw out every appearance-related comment during class, but suggests that they be judicious in their use of such dialogue.

The study was funded by a grant from the Association for the Advancement of Applied Sport Psychology.