What is HIT?

What is High Intensity Training?

High Intensity Training is a style of progressive resistance exercise characterized by a high level of effort and relatively brief and infrequent workouts, as opposed to typical training methods involving low to moderate levels of effort and longer, more frequent workouts. Nautilus inventor Arthur Jones helped define and popularize high intensity training in the 1970’s, often summarizing the general philosophy as “…train harder, but train briefer” or “…train harder, but train less often”.

Nautilus inventor Arthur Jones

Train Harder…

The most fundamental principle of exercise is overload. To stimulate increases in muscular strength and size you must impose a greater demand on the muscles than they are accustomed to. The harder or more intense an exercise is the greater the degree of overload and the more effective the exercise.

During high intensity training exercises are typically performed with all-out effort, until it is impossible to perform another repetition in good form. While training to momentary muscular failure is not necessary to stimulate increases in muscular strength and size, it ensures one has done all they can for that purpose. Some people believe regularly training to muscular failure is too stressful on the body – specifically the central nervous system – however this is not a problem as long as the volume and frequency of training are not excessive.

High intensity training methods vary with regards to the specific style, speed, and number of repetitions performed, as well as the number of exercises and frequency of workouts, but all emphasize working as hard as possible.

…But Train Briefer

There is an inverse relationship between exercise intensity and the volume of exercise you can perform. The greater the effort you put into a workout the shorter the workout must be to avoid overstressing your body. High intensity training workouts typically require around thirty minutes to complete, and some “consolidation” workouts may take less than ten.

Most high intensity training methods involve performing only one all-out work set per exercise. Although the majority of research shows no significant difference in effectiveness between single and multiple sets for improving either muscular strength or size for the majority of people, a few high intensity training methods prescribe two or three sets for some exercises.

High intensity training methods also vary in the total number of exercises performed per workout, from as few as two or three to as high as twenty when neck and grip exercises are included. The appropriate volume of exercise varies significantly between individuals based on genetics, age, and lifestyle factors such as quality and amount of nutrition and rest, as well as the specific training goals. Athletes or trainees with physically demanding jobs or lifestyles must also balance their training volume against the amount of other physically demanding activities they perform to avoid overtraining.

While some trainers claim high intensity training routines are only appropriate or effective for beginners due to the low volume, and that an increase in volume is required as a trainee becomes more advanced, empirical evidence shows as trainees become more advanced and capable of training with greater intensity a reduction in training volume becomes necessary to avoid overtraining.

Train Less Often

Intense exercise places a significant amount of stress on the body. Exercising too frequently, without allowing the body adequate time between workouts to recover, will eventually lead to overtraining and a lack of progress.

The majority of people on a high intensity training program should train no more than three non-consecutive days per week. More advanced trainees working at a much higher level of intensity or older trainees and others who don’t recover as quickly may get better results training even less frequently. Most high intensity training methods involve a starting frequency of two or three workouts per week, which may be adjusted depending on the trainees’ progress.

Mike Mentzer

General Guidelines for High Intensity Training

The following are general guidelines for high intensity training. Keep in mind the specific volume and frequency of training and exercise selection should be modified to suit the individual, based on level of conditioning, response to exercise, and goals.

  • Training Frequency: Beginners should perform no more than three workouts per week on non-consecutive days. Advanced trainees may need to work out less frequently, not more.
  • Training Volume: Perform one set of one to three exercises for each major muscle group (fewer exercises for full-body workouts, more for body-part workouts in a split routine).
  • Number of Repetitions: A wide range of repetitions can be effective, but for a good balance of muscular strength and size, cardiovascular and metabolic conditioning, and safety a moderate to high repetition range resulting in a time under load between 45 and 90 seconds is recommended .
  • Progression: Beginners should increase the weight used for an exercise by about five pounds or five percent (whichever is less) when the upper target repetition number can be completed in good form. Weight should be progressed by smaller increments as trainees become more advanced, and very advanced trainees should increase the weight by as little as one pound or one percent (whichever is less).
  • Repetition Speed: Move slowly enough to maintain strict control over your body position and path of movement and to reverse direction smoothly between lifting and lowering. Avoid fast, jerky movements.
  • Range of Motion: Full-range repetitions, partial-range repetitions, and isometrics are all effective when performed properly.

Examples of workouts based on these guidelines:

Basic full-body workout with Nautilus machines:

  1. Leg Press or Squat machine
  2. Pulldown
  3. Chest Press or Dip
  4. Compound Row
  5. Overhead Press
  6. Hip/Back Extension
  7. Trunk Curl
  8. Heel Raise
  9. Neck Flexion
  10. Neck Extension

Basic full-body workout with free weight and body weight exercises:

  1. Barbell Squat
  2. Chin Up
  3. Bench Press or Dip
  4. Bent Over Row
  5. Standing Press
  6. Stiff-Legged Deadlift or Hip/Back Extension
  7. Weighted Crunch
  8. Heel Raise
  9. Neck Flexion
  10. Neck Extension

Advanced trainees working at higher levels of intensity will require a reduction in training volume and frequency, and very advanced trainees may benefit from cutting back to as few as three to five exercises as infrequently as once every seven to ten days.

Full-Body or Split Routines?

Most high intensity training methods prescribe full body routines, however a few like Mike Mentzer’s Heavy Duty use split routines, which may allow for longer local recovery for certain muscle groups. Many popular split routines divide the the workouts between upper and lower body, between pushing and pulling exercises, or between upper body pushing exercises, upper body pulling exercises, and lower body exercises.

For examples of high intensity training split routines read High Intensity Workouts

Machines or Free Weights?

Although high intensity training is often associated with Nautilus exercise equipment due to it’s promotion by Nautilus inventor Arthur Jones, it can be performed effectively with any type or combination of equipment. While good equipment does make a difference it is not as important as how it is used.

Bodybuilding or Strength Training?

High intensity training is not exclusively for bodybuilding or strength training or any one aspect of fitness, and is effective for achieving a variety of exercise goals. In addition to building muscular strength and size, high intensity training is highly effective for improving cardiovascular and metabolic conditioning along with numerous other measures of health and fitness.


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Smith D, Bruce-Low, S. Strength Training Methods and The Work of Arthur Jones. Journal of Exercise Physiology Online 2004;7(6): 52-68

Darden, Ellington. The Nautilus Book: An Illustrated Guide to Physical Fitness The Nautilus Way. Chicago: Contemporary Books, Inc., 1981

Jones, Arthur. Nautilus Training Principles, Bulletin No. 1. DeLand, Florida: Nautilus Sports/Medical Industries, 1970

Jones, Arthur. Nautilus Training Principles, Bulletin No. 2. DeLand, Florida: Nautilus Sports/Medical Industries, 1971

Jones, Arthur. Nautilus Training Principles, Bulletin No. 3. DeLand, Florida: Nautilus Sports/Medical Industries, 1973

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