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High-Intensity Training - Fundamental Principles

Get Fit With High-Intensity Workouts


Updated September 05, 2011

If you are a casual reader of training and fitness information, you could easily be confused about “high-intensity training.”

Below are plain-language definitions for the three main variables in fitness training: "intensity", "volume" and "frequency". These definitions essentially apply to any type of training you do, from weights to track interval training or road running and cycling.

Intensity, in weight training, means how difficult it is to perform each repetition and set; that is, how heavy you lift. For cardio, it could mean how fast you run or walk on the treadmill, road or track.

Volume is how much of any exercise or how many exercises you do in a session or over time.

Frequency is how many sessions in a week, month or year that you complete at the intensity and volume you choose.

High-Intensity Aerobic and Anaerobic Exercise

Aerobic exercise
In addition to weight training, an overall exercise program may include elements of aerobic (cardio) and anaerobic training. Aerobic training is what you will recognize as treadmill jogging or walking, cycling or swimming at a low to moderate pace up to a point at which you can still carry on a conversation, even if you are breathing a little heavy. You should be able to keep this up for 30 minutes or more.

Low to moderate intensity aerobic exercise is at a heart rate of approximately 50 to 70% of your maximum heart rate. At this intensity, and with reasonable fitness, you should be able to supply the exercising muscles with sufficient oxygen to keep them contracting and performing for some time. Aerobic means “with oxygen.”

Anaerobic exercise
In contrast, anaerobic exercise is at an intensity at which your muscles’ requirements for oxygen exceed the amount you can supply by breathing and via your blood supply. At this exercise intensity, you will stop sooner rather than later because the muscles will fail to function. At this level of intensity, your heart rate may be at 90 to 100% of your maximum heart rate. This is clearly high-intensity exercise. Weight training for strength with heavy loads is usually anaerobic exercise for short bursts of effort.

High-intensity aerobic exercise
Now, you may have noticed a gap in the heart rates discussed above: the range from 70 to 90% of your maximum heart rate. When you start to exercise beyond about 75% of your maximum heart rate (where you can’t talk much because you are breathing hard), you are getting into what can reasonably be described as high-intensity exercise, even though it may still be aerobic. For fitter individuals, this may be fast running, cycling, rowing, swimming, or even race walking. At this intensity, you will be less likely to be able to exercise for the same duration as you could with moderate aerobic intensity.

It’s worth noting that this is the intensity zone where you will burn the most calories (and fat) during and after exercise -- duration of exercise being a factor. Lifting moderately heavy weights intermittently will put you in this zone, but your session won't be long enough to match a 45-minute run or cycle at this intensity. High-intensity aerobic and anaerobic training is the king of calorie burning, but you have to do it for sufficient time to get the most benefit.

High-Intensity Interval Training (HIIT)

High-intensity interval training is a system of training that utilizes short bursts of repeated running or cycling or similar activity. A HIIT training workout in a cycle spin session might look like this:
  1. Warm up. Spin for five minutes at slow pace or resistance (60%).
  2. Cycle for one minute at about 85% of your maximum effort. Spin easy for thirty seconds. Do this five times.
  3. Recover at slow pace as for step 1.
  4. Cycle flat out for fifteen seconds, rest for twenty seconds. Do this ten times.
  5. Recover at slow pace as for step 1.
  6. Cycle for three minutes at 75% of you maximum. Spin for one minute. Do this three times.
  7. Warm down similar to step 1.

This sort of training is common in gym cycle spin classes.

You could use a similarly structured intensity running program at an athletic track or even on a treadmill (if you’re careful), or even when swimming or rowing.

Related Video
Weight Lifting Exercises for the Chest
Exercises for Biceps and Triceps

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