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Study examines effectiveness of popular home, interval-training exercise program


SAN DIEGO, Calif. (Jan. 26, 2012)—The American Council on Exercise (ACE) announced the results of a study it commissioned to examine the effectiveness of P90X™, a 90-day, bootcamp-style home exercise program that is a popular example of the interval-training style workouts identified by ACE as one of the top fitness trends to watch in 2012.  The study found that the program meets or exceeds recognized standards for improving cardiorespiratory fitness.  ACE is America’s leading authority on fitness and the world’s largest nonprofit fitness and personal trainer certification, continuing education and training organization.


“P90X is among the most popular of the high-intensity, interval-style home workout exercise programs sweeping the nation, many of which promise to help individuals burn high amounts of calories in a short period of time,” said American Council on Exercise’s Chief Science Officer, Cedric X. Bryant, Ph.D.  “Our study results found P90X offers an effective workout, and, when combined with a sensible eating plan, we believe it can help many individuals achieve their weight-loss and fitness goals in the comfort of their homes.”


The study was conducted by a team of experts from the Departments of Exercise and Sport Science and Physical Therapy at the University of Wisconsin - La Crosse, and was designed to determine the true exercise intensity and calories burned when using the P90X program.  A group of 16 healthy subjects, ranging in age from 19 to 26, were enlisted for the study; participants completed up to three practice sessions of each of the four P90X workouts chosen for the study: Legs & Back, Plyometrics, Cardio X, and Chest, Shoulders & Triceps. 


Once each subject was proficient in the workouts, the actual testing began.  Each participant exercised to the best of his abilities throughout the warm-up, conditioning phase and cool-down, as researchers recorded the subject’s heart rate at one-minute intervals.  At the end of each workout, ratings of perceived exertion (RPE) were recorded, while the heart-rate data was utilized to determine the subjects’ predicted maximal oxygen consumption and caloric expenditure.  The participants were given 48 hours of recovery rest between each workout test. 


After the results were tabulated, the female subjects demonstrated slightly higher numbers of heart rate maximum and maximal oxygen consumption than the male subjects, and the percentages for both groups registered well within the range to provide a high-intensity dose of exercise.  The tests also found the male subjects burned an estimated 441 to 699 kcals burned per workout, and females a total of 302 to 544 kcals per workout.   

“The American Council on Exercise tests programs like P90X as part of our mission to help empower the American public with the information and tools needed to live a fit and healthy lifestyle.” continued Bryant.  “High-intensity, interval-style home exercise programs can be a time-efficient workout for many individuals—particularly those with a baseline level of fitness.”

A summary of the study can be found online in the ACE® Certified News online magazine. 

About ACE
The American Council on Exercise (ACE), America’s premier fitness and personal trainer certification, continuing education, and training organization, is a nonprofit organization dedicated to promoting the benefits of physical activity and protecting Americans against unsafe and ineffective fitness products and instruction.  ACE sponsors university-based fitness and exercise science research studies and is the world’s largest nonprofit fitness certifying organization.  For more information on ACE and its programs, call (800) 825-3636 or visit the ACE website at  AMERICAN COUNCIL ON EXERCISE, ACE and the ACE logos are Registered Trademarks of the American Council on Exercise.

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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.