How does the Insanity Workout Program get you to burn up to 1,000 calories an hour? How does it get you in peak physical shape in only 60 days?

The short answer is Maximum Interval Training.

What is Interval Training?

The basic definition of interval training is physical training that involves bursts of high-intensity exercise, alternated with periods of rest or lower-intensity activity. For example, run as fast as you can for 30 seconds, jog slow for 90 seconds, and repeat for 30 minutes. The Insanity Workout is based on this method of training, but with its own twist.

Interval training is nothing new, but has only entered the mainstream in the past two decades or so. It has been a staple of athletic conditioning for many years before that.

How Interval Training Works

Interval training works both the aerobic and anaerobic systems. Aerobic means “with oxygen,” and refers to the use of oxygen in the body’s energy generation process. Anaerobic, meaning “without oxygen,” refers to the absence of oxygen in the energy generation process, where the muscles cells must rely on other reactions within the body to fuel muscle contraction.

We are never 100% doing aerobic or anaerobic exercise. The scale tips to one side or the other depending on the intensity. As intensity gets higher, we rely more on the anaerobic process because we simply cannot inhale oxygen fast enough.

To put it simply, anaerobic exercise is high intensity exercise (like running sprints). Short bursts of activity uses energy stored in the muscles (glycogen) to provide energy. The by-product of this process is lactic acid, which creates the burning sensation we feel during high intensity exercise. (Although other factors play a role in pain during these activities)

When we finally come to rest or slow down, the heart and lungs work together to break down the lactic acid. The aerobic system is back in control, using oxygen to convert stored carbohydrates into energy.

Benefits of Interval Training

There are many types of interval training that have emerged over the years but the benefits are many. Cross-training, Tabata-running, HIIT, you name it- they are all forms of interval training.

Your body will respond to repetitive interval training (known as adaptation response). It will build new capillaries so its more effective at delivering nutrients and oxygen to the working muscles. The heart strengthens and your cardiovascular system improves. Interval training is also effective at preventing injuries associated with long endurance exercises.

Overall, interval training is much more effective for weight loss than moderate exercise over a longer period of time. It has been proven to burn more calories in less time when compared to lower intensity exercising for longer periods.

So What’s Max Interval Training?

Shaun T’s Insanity Workout Program takes traditional interval training and flips it around.

With traditional interval training, your high-intensity exercise would last 30 seconds, followed by roughly 2-3 minutes of rest. Insanity uses the opposite interval – 3 minutes of high-intensity followed by 30 seconds of rest.

Essentially your high intensity period (anaerobic exercise) is much longer than traditional interval training. Your heart rate should go above and beyond 80% of its maximum capacity, and your body is forced to use fast-twitch muscle fibers that aren’t usually hit with cardio or weightlifting exercises. When you hit the lower-intensity periods, these muscles continue burning extra fuel (carbohydrates and fat) even though you’re at rest.

If you want to read more about slow and fast-twitch muscle fibers, check out these articles at BodyBuilding.com and About.com

The trade-off is difficulty. Going all out for 3 minutes at a time is exactly what boxers do. Boxers are typically highest on the fitness and conditioning ladder when it comes to athletes, but their training is usually the most difficult of any sport.

The benefits are very fast changes in your body composition. Insanity uses only the resistance of your own body, so your cardiovascular ability improves quickly, you body fat percentage drops like a rock, and your muscles get sculpted. Since Insanity doesn’t use any weights, your muscles won’t grow in size but they will improve in power.

In a short period of time, your body becomes a lean, mean, ass-kicking machine.

• Insanity Workout Program by Shaun T
• Insanity Max Interval Training