http://www.multibriefs.com/briefs/acsm/active7-26.htm
This article is from the American College of Sports Medicine (ACSM) on High Intenstity Training. It is discussing the improvement of body composition in overweight and obese individuals when put through High Intensity Interval Training. ACSM has established that training at High Intensity Intervals for just 20 minutes 3 times a week can improve metablic changes and body composition!
Active Voice: High-Intensity Exercise for Overweight and Obese People
By Hassane Zouhal, Ph.D.
Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily reflect positions or policies of ACSM.
Hassane Zouhal, Ph.D., is Professor in the Department of Sports Sciences at the University of Rennes 2 ENS Cachan, France. He is a member of the Movement Sports and Health Sciences Laboratory. His research focuses on metabolic and hormonal responses to physical exercise and training, with special emphasis on influences of type of training, gender and aging. This commentary presents his views associated with the research article he and his colleagues published in the March 2011 issue of Medicine & Science in Sports & Exercise®.
Physical activity is widely recommended for obese adults and children, based on extensive evidence of both health and functional benefits. Despite the widespread acceptance that undertaking physical activity is associated with a reduced risk of obesity and many other diseases, participation in regular physical activity remains low. As lack of time has regularly been shown to be a major barrier to physical activity and has been associated with low physical activity levels, recently the American College of Sports Medicine recommendations have placed greater emphasis on shorter-duration (i.e. a minimum of 20 minutes), higher-intensity exercise (HIE) done a minimum of three times per week. However, there is still much debate concerning the optimal intensity, duration and volume of exercise needed for the most favorable impact on health.
HIE training, characterized by several sessions of brief, repeated bouts of supramaximal exercise, may be a time-efficient strategy for inducing metabolic adaptations in human skeletal muscle. This type of training has been proposed as a viable alternative to classically prescribed submaximal endurance training. Recently, several scientific studies have shown this type of exercise can be tolerated by overweight/obese sedentary individuals with low fitness levels. Whyte and colleagues demonstrated that only two weeks of high-intensity sprint interval training on a cycle ergometer substantially improved a number of metabolic and vascular risk factors in overweight/obese sedentary men, highlighting the potential for this alternative exercise model to improve vascular and metabolic health in this population.
Today, there are many reasons (social, psychological, etc.) to encourage HIE training within overweight and obese populations. First, HIE training represents a remarkably efficient routine, and it is more compatible with the time-constrained modern lifestyle of Western countries. Second, as sedentary individuals have difficulty performing continuous submaximal exercise and often perceive it to be monotonous, HIE training may be more attractive. Third, HIE training offers a greater stimulus for skeletal muscles than continuous submaximal exercise, and a high level of muscular power is needed to perform this type of exercise. HIE training has been shown to result in maintenance of and even improvement in muscular strength. Hence, recently it has also been reported that HIE induces greater changes in body composition than energy-matched lower-intensity exercise (for detail, see Irving et al.).
Therefore, HIE may offer a more time-efficient strategy for improving metabolic health than conventional moderate-intensity exercise programs. There remains an ongoing need, however, to identify the appropriate types of exercises with suitably low durations that will negate time from being a barrier to exercise and will facilitate increases in physical activity levels.
