A new study conducted by researchers at Northwestern University reports that trainers using appearance-based language to motivate women exercisers are less successful than instructors who focused on the health and strength benefits of the same workouts.

The Northwestern research team set up two identical conditioning classes and divided 203 women participants into classes of 16 minutes each. The only difference was the messaging.

While one class was encouraged using phrases like “strengthen core muscles” and “this develops your strength so you can run, jump, and sprint like a super hero,” the other class heard comments focused on weight loss and body-shaping.

While participants in the health-based class reported feeling “strong” and “accomplished” after the workout, participants who heard more common phrases such as “no more thunder thighs for us” and “get rid of that cellulite” reported feeling more body-conscious and ashamed.

Renee Engeln, the study’s head author and professor of instruction in the psychology department at Northwestern, told Insider, "If we want people to stick with exercise, we need to remove shame from the equation."

"It is important not to underestimate how these comments about 'bikini bodies' and 'ditching love handles,' even when rare, can negatively impact the women who hear them,” she said. There is no compelling reason to make these types of comments.”

Courtney Cameron is Editorial Assistant of Athletic Business.