// 20-Minute Fat Loss: Is it possible?
by Amy Jayasuriya
Since Johnny G introduced his concept of ‘Spinning’® to the fitness industry, indoor cycling has become one of most popular classes on group fitness timetables the world over. More and more participants of all age groups and fitness levels are enjoying the experience they receive at the hands of committed and passionate instructors. But would even more people be participating if the experience could be more easily fitted into their day?
The busy, results-driven lifestyle that many people live today has resulted in a continual search for innovative ways to get fit and lose body fat in less and less time (and often with less effort).
Researchers at the Medical Faculty at the University of New South Wales, led by Professor Steve Boutcher, found that a 20-minute indoor cycle workout consisting of eight-second sprints followed by 12-second relative rest periods, resulted in significantly more fat loss than 40 minutes of hard, steady state exercise. Both protocols were performed three times a week for 15 weeks.
The research, conducted in 2007 with more insight in 2008, was conducted to determine the duration of the least amount of exercise necessary for the greatest amount of fat loss.
It has long been known that a nutritious balanced diet combined with exercise is the key to keeping weight under control. Traditionally, the exercise component of this equation has comprised 60, 30 or 20-minute workouts in the fat burning zone in order to reduce body fat. However, according to Boutcher’s research, spending less time exercising resulted in fast fat loss when interval training was used.
An insight into the research
The main aim of the University of NSW study was to determine the effects of a 15-week high intensity intermittent exercise (HIIE) program in subcutaneous and trunk fat and insulin resistance of young women.
The research involved a group of 45 women with varying body mass indexes (BMI) and ages, who were assigned to either steady state exercise or HIIE programs for a period of 15 weeks.
It was found that both exercise groups showed increases in cardiovascular fitness, however the HIIE group had a reduction in total body mass and fat loss.
So, in a nutshell, the findings appear to suggest that interval training is best – but what exactly is it? Interval training is broadly defined as repetitions of high-speed/intensity work followed by intervals of rest or low activity. This training technique is often practiced by long distance runners (800 metres and above) although some sprinters and footballers also use it.
However, the term ‘interval training’ is also often used to refer to any cardiovascular workout (e.g., indoor cycling, running, rowing, etc) that involves brief bouts of exercise at near maximum exertion, interspersed with periods of lower-intensity activity.
The study found that subjects involved in the research showed significant changes in their blood markers and increased the amount of muscle in their legs and trunk area due to the effects of sprinting on fast twitch skeletal muscle fibres.
Muscle groups in the body comprise two types of fibres: slow-twitch and fast-twitch. Understanding the difference between the two, as well as the training methodologies which lead to successful training of each area, will lead to the recruitment of the highest possible number of fibres.
Slow-twitch: Also known as type I fibres, these have very strong aerobic ability for oxidation, contract very slowly, and are very useful in endurance activities. These muscle fibres are ‘high’, or engorged with nitrogen-rich blood during higher rep training and allow us to walk and jog.
Fast-twitch: Also known as type II fibres, these assist with short, heavy lifting and activities requiring short bursts of power. They are very useful for brief, high-intensity training such as sprints. About half the muscle fibres of an average person are fast twitch and most store a large amount of fat. The researchers found that most people hardly used their fast twitch fibres in their daily living or in their exercise workouts.
The 8/12-second combination can be used in aerobic exercise such as steady state walking and jogging, however results are better when used in anaerobic exercise such as sprints.
The principles of this training can be incorporated into boxing, rowing, skipping and even walking, although indoor cycling offers one of the most effective methods of employing it. By sprinting for eight seconds all out and then pedalling slowly for 12 seconds, and building up to a duration of 20 minutes three times a week, the fat loss results will follow.
- University of New South Wales, Medical Faculty Research Team, 2007
- Trapp G, Chisolm D & Boutcher, S. H (2007). ‘Metabolic response of trained and untrained women to high intensity to intermittent cycle exercise’. American Journal of Physiology (Rgular Integr Comp Physiol), 293: 2370-2375
- Trapp G, D ,Freund, J & Boutcher, S.H. (2008). ‘The effects of high intensity, intermittent exercise training on fat loss and fasting insulin levels of young women.’
An established national and international presenter, cycle trainer and instructor, Amy has experience as a club coordinator and training program developer. She is also the Australian master trainer for Gymstick Pilates and a Soma Chi yoga teacher. Amy brings discipline, motivation and passion to her training courses and classes.
NETWORK • SUMMER 2009 • PP56-57