by Rebecca Goodrich
Interval training consisting of intense exercise punctuated by short periods of rest can yield impressive increases in many metabolic processes.
Hammer those bike pedals till your feet are a blur. Your heart pounds, and each ragged inhalation feels like it might be your last. Just when you can’t manage one more revolution, you ease off the gas and cruise at a steady cadence to catch your breath. Checking your pulse, you note that it’s dropped by twenty beats per minute. But you don’t get too comfortable. After one minute of rest you’re off in another high intensity sprint. If this scenario sounds familiar, then you already know the power and effectiveness of interval training. Interval Training
Intervals: short bursts of high intensity exercise punctuated by even shorter periods of rest. As far back as the 1950s, scientists and athletes discovered that interval training yielded remarkable physiological results in a short amount of time. Since then, hundreds of studies have documented the power of interval training for women, for recreational and elite athletes, for patients with heart disease and breathing disorders, to name just a few.
What the Research Says
In the aptly named study “Two Weeks of High-Intensity Interval Training Increases the Capacity for Fat Oxidation During Exercise in Women” published in the Journal of Applied Physiology, December 2006, only seven sessions of high-intensity interval training over two weeks brought about a 36% increase in whole body fat oxidation along with many other positive metabolic changes in women who were moderately fit.
In the April 2008 study “Metabolic Adaptations to Short-term High Intensity Interval Training: A Little Pain for a Lot of Gain?” published in Exercise and Sport Reviews, researchers Martin Gibala and Sean L. McGee conclude that: “High-intensity interval training is a potent time-efficient strategy to induce numerous metabolic adaptations usually associated with traditional endurance training.”
Although many different interval formulas have been tested, no clear favorite has emerged as the optimum combination of exercise and rest. Most sport science experts recommend periods of high intensity exercise ranging from 1-4 minutes at 80-85% of maximum heart rate followed by rest periods of 30 seconds to one minute.
Weightless Interval Training
One popular example of interval training is a system taught by sport scientist and entrepreneur Kiya Knight. By studying cutting edge research and applying those insights to her personal training practice, Knight has developed a highly efficient interval protocol called Weightless due to its emphasis on body weight exercises and ease. A Weightless interval workout consists of three rounds of eight exercises. In the first round, each exercise is performed at high intensity for ninety seconds. After a one minute rest the second round consists of the same eight exercises performed for 60 seconds each. The workout concludes with the third round of exercises performed for 30 seconds each.
“It makes sense to exert yourself at the start of the workout when you’re fresh and can maintain good form,” Knight says. “The thirty second round is just as tough as the first, but you stay motivated psychologically because it’s so much shorter.” Her Manhattan clientele agree:
“Kiya’s personal story of health and fitness is astonishing. I want this kind of personal trainer at home! Kiya pushed me physically and mentally. Intense workouts completed in 30 minutes just 1 minute at a time! She taught me that my body is able if I am willing, making me feel accomplished, powerful, successful, and strong.” Deana, Bikini Bootcamp Participant 09′
If your fitness regimen has gotten stale and your diet has plateaued, consider increasing the efficiency of your workouts with interval training. The next time you do cardio, simply up the intensity for one or two minutes, then relax while continuing to pedal or step. Repeat the cycle several times.
Give the Weightless protocol a try by choosing 4-8 bodyweight exercises that work a variety of muscles. Do not use weights as it is difficult and potentially dangerous to lift weights rapidly. While maintaining good form, perform each exercise at a moderate to high rate of speed for ninety seconds. Rest for one minute. Repeat the cycle of exercises just as you did before, but this time for sixty seconds each. Again, rest for one minute. Now blast through each exercise for thirty seconds using maximum effort.
In a workout lasting less than thirty minutes you will have initiated a cascade of positive metabolic changes ranging from increased fat oxidation to improved circulation and increased respiratory endurance. Studies haven’t yet linked interval training to smaller jean sizes—you’ll have to conduct that research yourself.