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ACE Evaluated Effectiveness of Electronic Muscle Stimulation Device for the Buttocks

SAN DIEGO (May 18, 2010)—The American Council on Exercise (ACE), America’s leading authority on fitness and the largest non-profit fitness certification, education and training organization in the world, today unveiled the findings of an exclusive study on the Slendertone Bottom Toner, an electronic muscle stimulation (EMS) device designed to tone the buttocks.  The study, which was conducted in conjunction with the exercise and health program at the University of Wisconsin, La Crosse, concluded that, while the Slendertone Bottom Toner may be effective at improving buttocks strength and endurance, it does not offer the overall health benefits of regular exercise.

“While in-home EMS products have improved in recent years, many of these devices still offer consumers the promise of improved muscle tone and appearance without exercise,” says ACE’s Chief Science Officer, Cedric X. Bryant, Ph.D.  “With this in mind, we set out to determine the relative effectiveness of the Slendertone Bottom Toner compared to a traditional exercise for the glutes.”

EMS technology, which consists of placing electrodes on the skin that deliver electrical impulses to the muscles below causing them to contract, has existed for decades.  The manufacturers of these devices have marketed them as an exercise-free method of improving muscle tone and overall appearance of frequently cited trouble spots like the abdominals, triceps and buttocks.  ACE first examined the efficacy of EMS in early 2000, when it sponsored research with the University of Wisconsin, La Crosse, on an EMS-based device promising rock-hard abs, which found the products to fall short of their promises.  According to ACE, the Slendertone Bottom Toner has proved more effective than its earlier counterparts, delivering on its claims to improve buttocks strength and endurance.

For the study, a team of University of Wisconsin, La Crosse, researchers, led by John Porcari, Ph.D., Stephanie Tepper, M.S., Mary Patrek, M.S., Josh Wilson, M.S. and Sarah Horlitz, M.S., recruited 72 healthy women from 20 to 60 years old who were not engaged in any lower-body training in the previous six months as test subjects.  Participants underwent a series of assessments, including questionnaires, a buttock circumference evaluation, muscle tone test and strength and endurance assessments, to form a baseline assessment for buttocks strength and endurance.

Following six weeks in which one group participated in conventional exercise and one participated in stimulation with the Slendertone Bottom Toner, the study revealed that the device was as effective as a regular regime of conventional quadruped hip extension exercise in terms of buttocks strength and endurance.  Although there were no meaningful changes in body weight, BMI or hip circumference, both groups showed significant improvement in buttocks strength (9 percent for the exercise group and 15 percent for the stimulation group) and endurance (26 percent for the exercise group and 29 percent for the stimulation group).  Further, both groups reported improvements in positive feelings on buttocks firmness, strength, tone, shape and appearance. 

While the ACE study supports the Slendertone Bottom Toner’s claims in ability to improve buttocks muscle strength and endurance, Bryant cautions against equating the benefits of the device with the overall benefits of regular exercise.

The stimulation group spent significantly more time using the EMS device than the exercise group spent working out (30 minutes vs. 5 minutes).  “If the individuals in the exercise group devoted an equivalent amount of time to traditional exercise as the individuals in the stimulant group did to using the device, their results would have likely exceeded those of the EMS device,” says Bryant.  “People often cite lack of time as one of the chief reasons they don’t exercise, but if you can find 30 minutes a day to shock yourself, you should be able to find 30 minutes a day to engage in physical activity that will provide you with all of the benefits of exercise that an EMS device can’t offer, including improvements in overall health, reduced risk of disease, reduced stress, enhanced mood and weight loss.”

A full study summary can be found on ACE’s “Get Fit” Web site, designed to inform, inspire, educate and motivate people to become fit and lead a healthier, more active lifestyle, located at

About ACE
The American Council on Exercise (ACE), America’s premier certification, education and training organization, is a nonprofit organization dedicated to promoting the benefits of physical activity and protecting consumers against unsafe and ineffective fitness products and instruction. ACE sponsors university-based exercise science research and is the world’s largest nonprofit fitness certifying organization. For more information on ACE and its programs, call (800) 825-3636 or log onto the ACE Web site at


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Founded in 1985, the American Council on Exercise (ACE) is a nonprofit organization committed to America's health and wellbeing. Over the past 30 years, we have become an established resource for health and fitness professionals, and the public, providing comprehensive, unbiased research and validating ourselves as the country's trusted authority on health and fitness.

Today, ACE is the largest nonprofit health and fitness certification, education and training organization in the world with more than 65,000 certified professionals who hold more than 72,000 ACE Certifications. With a long heritage in certification, education, training and public outreach, we are among the most respected organizations in the industry and a resource the public has come to trust for health and fitness education.