Celebrity fitness guru Tracy Anderson is being criticized by fitness trainers after saying she doesn't recommend spinning workouts because they make your thighs fat.
"Unless that person has significant predisposition for laying down muscle mass, it's very unlikely spinning will result in massive quads or change in scale weight," Cedric Bryant, the chief science officer for the American Council on Exercise, told ABC News.
"The average person doesn't have the genetic capability of developing that kind of mass even if they work out really hard."
The backlash erupted after Tracy told Redbook that spinning isn't ideal for weight loss because the rigorous cardio exercise bulks up your thighs — something no woman wants.
"Spin may burn calories in the short term, but if that's all you're doing, it'll bulk up your thighs," said Anderson. "I have women who come into my office after spinning exclusively for six months, wondering why they can't fit into their jeans."
After being slammed for misrepresenting the weight-loss and toning aspects of spinning, Tracy clarified her statement:
"I've never said that spinning makes you gain weight," she said. "What I've said is that spinning creates an imbalance in the muscular system. It bulks the thigh and butt muscles. You develop mass by working these same muscles over and over."
Some personal trainers agreed with Anderson, noting that spinning can increase appetite and develop muscular thighs, but most fitness experts disagreed.
"It's so wrong and there is so much data that clearly shows otherwise," said James O. Hill, an exercise physiologist and professor at the University of Colorado School of Medicine.
This isn't the first time Anderson's workout methodology has come under fire. Many trainers disagree with Tracy's recommendation that women should not lift weights over three pounds. Anderson also said running is not good for weight loss.
Anderson's workouts typically combine high-intensity cardio-dance exercise with light strength-training using body weights and high repetitions done with low weights.
Whether you agree with her methods or not, Tracy has sculpted the bodies of some of Hollywood's skinniest celebrities, including Gwyneth Paltrow and Victoria Beckham.
Anderson, creator of the bestselling Tracy Anderson Method workout DVD, and dishes weight-loss secrets in her book, Tracy Anderson's 30-Day Method: The Weight-Loss Kick-Start that Makes Perfection Possible.