High Intensity Interval Training.

What Is HIIT?

Interval training has been the basis for athletic training routines for years. The first forms of interval training, called "Fartlek" involved alternating short, fast bursts of intensive exercise with slow, easy activity. Fartlek was casual, unstructured training that perfectly fits it's English translation: "speed play."

The interval programs of today have become highly sophisticated methods of structured training for athletic performance enhancement. Physiologists and trainers have designed interval programs that are specifically suited to individual athletes. These sessions include precisely measured intervals that match the athlete's sport, event and current level of conditioning. Often the appropriate intensity and duration of the intervals is determined by the results of anaerobic threshold testing (AT) that includes measuring the blood-lactate of an athlete during intense exercise.

How Interval Training Works

Interval training works both the aerobic and the anaerobic system. During the high intensity effort, the anaerobic system uses the energy stored in the muscles (glycogen) for short bursts of activity. Anaerobic metabolism works without oxygen. The by-product is lactic acid, which is related to the burning sensation felt in the muscles during high intensity efforts. During the high intensity interval, lactic acid builds and the athlete enters oxygen debt. During the recovery phase the heart and lungs work together to "pay back" this oxygen debt and break down the lactic acid. It is in this phase that the aerobic system is in control, using oxygen to convert stored carbohydrates into energy.

This repetitive form of training leads to the adaptation response. The body begins to build new capillaries, and is better able to take in and deliver oxygen to the working muscles. Muscles develop a higher tolerance to the build-up of lactate, and the heart muscle is strengthened. These changes result in improved performance particularly within the cardiovascular system.

Interval training also helps prevent the injuries often associated with repetitive endurance exercise, and they allow you to increase your training intensity without overtraining or burn-out. In this way, adding intervals to your workout routine is a good way to cross train.

According to the American College of Sports Medicine, more calories are burned in short, high intensity exercise. If you are counting calories burned, high intensity exercise such as intervals are better than long, slow endurance exercise. You don't need to be a world-class athlete and have sophisticated blood analysis to take advantage of the benefits of interval training. The standard "speed play" training of fartlek works well for the rest of us. This type of interval work is based upon your subjective needs. Simply pay attention to how you feel and set your intensity and duration accordingly.

Precautions for Safe Interval Training

Warm Up before starting intervals

Assess current conditioning and set training goals that are within your ability

Keep a steady, but challenging pace throughout the interval

Build the number of repetitions over time

Bring your heart rate down to 100-110 bpm during the rest interval

To improve, increase intensity or duration, but not both at the same time

Make any changes slowly over a period of time

Train on a smooth, flat surface to ensure even effort

Below; is a basic training plan which can be followed until a good level of fitness has been achieved.

Don't forget to warm up and then...
30 Second Sprint
30 Second Slow Jog
45 Second Sprint
45 Second Slow Jog
60 Second Sprint
60 Second Slow Jog
45 Second Sprint
45 Second Slow Jog
30 Second Sprint
60 Second Walk

Your aim is to complete three full sets of the above pyramid however; this WILL NOT be achievable until a very good level of fitness has been gained, so don’t get disheartened.

Remember, start off gently and build your fitness slowly over a period of time. It is advisable to replace the sprinting sections of the pyramid with ¾ pace jogs for the first few attempts. Don’t forget to warm-up properly and to cool down at the end of your exercise.