Interval Training

Interval Training

"The worst thing you can do is: NOT TRY!"

Over the past century, there has been a massive assault on athletic performance records. Notice how sharply the records have fallen. Similar record-breaking trends are common in competitive swimming and bicycling events as well as in many other sports activities.

One of the many factors that have undoubtedly contributed to this is improvement in training techniques and methods. Refinement of one such method, interval training (ITP). Has probably produced more successful athletes then has any other system, of conditioning. Simply: ITP is a series of repeated bouts of exercise alternated with periods of relief (rest).

What is the major difference between ITP and other conditioning programs? The answer is simple. Most conditioning programs are conducted on a continuous basis without regards to rest periods. Scientific evidence supports the idea that a proper work to-relief ratio is the key to ITP success.

Can one convert his present exercise program to an interval training program using any method of exercise? Yes, and he should: Cooper's aerobics, the Canadian 5BX or XBX plans, calisthenics, running, cycling, swimming; as a matter of fact, man should do all physical work in intervals, rather than continuously. More work and less fatigue will be the reward.

Fundamental ITP guidelines allow programs to be constructed for the most debilitated as well as for the Olympic contender. Studies of many specialists support such claims. The rest interval incorporated into the ITP disallows accumulation of fatigue products associated with blood pressure increases and cardiac work load. It also has been reported that ITP has been used successfully with individuals over 70 years of age.

For the coach and athlete, interval training programs should form the basis of conditioning for all sports. We recognize that there is a specificity or particular program for the line backer, sprinter, pitcher, moto-cross rider, BMX rider and so on. Maximum performance will be realized only through marrying the individual to a program designed especially for him. Mass physical training programs, including continuous drills and general calisthenics pr the "two-mile run for all," are as antiquated as bloomer gym suits for girls.

Success in designing individualized ITP's ( and understanding why interval training is more successful than other programs) requires an elementary understanding of exercise physiology. Think of the cellular level were the action begins. You need to understand that for example, the energy for performing the shot-put is supplied in a different manner the that for, say running or cycling for a couple of miles. Knowing the particular manner in which energy us supplied for a given activity or exercise allows you to construct the very best ITP program to develop that system. The ITP program for the Tour de France cyclist will be different from one for a BMX racer. Experience and, more recently, scientific studies have produced basic guidelines which allow formalization of specific exercise prescriptions (ITP) for the individual athlete, whatever the event. These fundamental principles apply equally to all sports, and include conditioning of the non-athlete.

The key to success in interval training lies in utilizing the proper intensity of exercise followed by a rest interval. As was previous mentioned, the rest interval prevents accumulation of fatigue products, thus permitting more intensive workouts without the additional pains of fatigue.


In this section I will try to explain in short, for your understanding and motivation what energy for performance stand for. Increasing energy potential of the muscle cell for a particular physical task is what this section is all about. Properly structured Interval Training Programs (ITP) can best do this. How energy is produced most effectively and efficiently for a specific activity is our immediate topic. For example, understanding the differences in ITP schedules (prescriptions) for dashing as opposed to distance running, or cross country skiing as opposed to slalom of BMX, is necessary in designing the ITP.

a. Adenosine triphosphate (ATP):

The muscle's energy source. A profound series of chemical reactions occurs when man performs a physical activity. We need only be concerned here with the final end product, adenosine triphosphate (ATP). ATP is defined as a nucleotide compound occurring om all cells but chiefly in striated muscle tissue, ATP is the energy reserve of the muscle. Our immediate concern: How is ATP supplied to the muscle cells?  There are three ways in which this occurs. Two methods are labeled anaerobic because oxygen is not a prime ingredient in ATP production. Anaerobic literally translated means without oxygen. The third method is called aerobic because oxygen is a prerequisite for manufacturing ATP. Aerobic means with oxygen.

The three chemical systems for ATP production are as follows:

  1. the APC-PC system (anaerobic)
  2. the lactic acid system or LA system (anaerobic), and
  3. the oxygen or aerobic system (O2).

These three methods of ATP production are best illustrated through use of examples. ATTENTION: by reading all of the above and what is still to come on this subject, be alerted to one important concept - whichever one of the three methods of ATP replenishment predominates, that particular source will be directly dependent upon the time it takes to perform the activity or physical task. For example, the 100 meter sprint, the 400 meter run, the 5 km run each require ATP through a predominantly different chemical system. Already you are probably beginning to realize that the time required in performance is the key factor in structuring the proper ITP. Some trainers/coaches refer to this concept as the specificity of training I will talk about it more later.

b. The ATP-PC system.

Phosphocreatine (PC) is stored in muscles. Almost instantaneously, PC can manufacture the prime energy substance, ATP, which is also stored in muscles. Activities, whatever they may be performed at maximum intensity in a period of ten seconds or less derive energy (ATP) predominately through the ATP-PC chemical system. The ATP-PC system is a valuable energy system for the entire animal kingdom. The tiger springing to his food, the flushed bird flying from its hiding place, the ground hog scurrying to his den, and the Olympic athlete sprinting to a gold medal are all good illustrations.

Like all good things, however, there are limitations. The ATP-PC system mechanism suffers in that only relatively small quantities of both ATP and PC can be stored in muscles. Thus, the supply does not last long, 10 seconds or less. However, ITP's can be structured to encourage greater cellular storage of ATP and quite possible PC. Increased capabilities of the athlete are consequential.

c. The Lactic Acid or LA system (anaerobic system):

In 400 meter and 800 meter sprints, as well as during the latter part of 1 ½ km race,the LA system for ATP replenishment predominates. The LA system derives its name from the excessive amounts of lactic acid occurring in the blood stream resulting from the activity. Properly associated with painful fatigue, lactic acid accumulates because there is an inadequate amount of oxygen available at the cellular level. The ATP-PC has been depleted and the only means for additional production ofATP is through the release of energy from the breakdown of food. In this case, sugar (glucose) is the preferential and, indeed, the only food source. It, too is stored in muscles. When the oxygen supply is inadequate, glucose is chemically broken down to lactic acid, allowing ATP to be manufactured. The lactic acid causes chemical fatigue, so to speak, and it is a real fatigue: ask any athlete, particularly a participant in a 400 meter dash or BMX race (400 meter or longer track, when going at top speed).

High intensity efforts requiring one to three minutes performance times primarily draw energy from the LA system (BMX 30 till 45 seconds per lap!). ITP properly designed for these events will increase the amount of sugar stored in the muscles and develop greater efficiency for these cells to breakdown sugar, allowing the production of ATP.

d. The Oxygen or Aerobic System:

Does it seem strange to you that oxygen was not required in our first two energy systems? Yet no animal can survive for long without it. After a few minutes without oxygen there will be no ATP, no energy and no life. In the presence of oxygen (aerobic) the foods man eats, especially carbohydrates and fats, provide for constant production of ATP for use by the muscle cells. A prima donna in ATP production, the aerobic system is essential for man's continuous existence. It not only produces ATP most efficiently and most abundantly but it is also the prime source during what we shall call endurance events: 5 or 10 km, cross-country and marathon performances. An ITP designed specifically for such events will enhance storage of foodstuffs and increase the ability of muscle cells to consume oxygen and thus to manufacture ATP.

Short revue of the above:

ATP is the immediate form of energy. It is supplied in three ways:
1. By the oxygen system, 2. by the LA system and 3. via the ATP-PC system.

The capability of each system to supply the major portion of the ATP required is related to the specific kind of activity or event performed. Observe that all three systems contribute ATP during performance of each and every activity. Notice too, that one system usually contributes more during one activity than do the other systems.


It will go too far, to explain all in detail. All of the above also shows you, that professional management by an official trainer at top level in BMX is absolutely essential. To give you all the general idea, I will provide you with several ITP programs, on running and on bicycling (road). Also an interval training with sub-maximum weights (power) will be part of this section, all very useful for BMX racers.

As a final consideration, I will give you guidelines from which you can more easily determine the major energy system or systems involved during the performance of any activity. To do this I will divide the continuum of performance times into four distinctive areas, as shown in tabel A. The first area includes all activities requiring performance times equal to or less than 30 second's duration. In such activities the predominant energy system, and the one that must be developed through training to improve performance, is the ATP-PC system.  Area two includes those activities requiring between 30 seconds and 1 - ½ minutes to perform. The predominant energy systems are both the ATP-PC and the lactic acid systems. Thus, to improve performance here, an ITP would be constructed such that the energy capacity of both these systems would be increased. The third area takes into account those activities requiring between 1 - ½ to 3 minutes to perform. Here also, as in area 3, there are two major energy systems involved, the lactic acid and oxygen systems. Again, improving these two energy systems will improve performance in those activities classified in this area.
Area four represents those activities which require performance times equal to or greater than 3 minutes in duration. Here, the major supply of ATP will be contributed by the oxygen system, and improvement in this system will assure improvement in performance.

Table A: Four work effort areas with performance times, major energy system(s) involved and examples of the type of activities.

1.  Less than 30 seconds  ATP - PC Shot-put, 100 yd, sprint, base stealing, golf and tennis swings
2. 30 seconds to 1½ min ATP - PC - LA 220-440 yd. Sprints, half-backs, speed skating, 100-yd.swim, BMX 
3. 1½ min to 3 min LA and O2 880 yard dash, gymnastic events, boxing (3 min. rounds), wrestling (2 min. periods) 
4. Greater than 3 min O2 Soccer and Lacrosse (except goalies), cross- country skiing, marathon run, jogging


  • ITP stands for Interval Training Program
  • ATP stands for Adenosine triphosphate - the muscle's energy source (energy reserve of the muscle)
  • PC stands for Phosphocreatine
  • LA stands for Lactic Acid
  • O2 stands for Oxygen

A few more general remarks and advises:

One advantage ITP has over continuous programs is that body heat does not accumulate nearly as rapidly, primarily because of the short exercise periods followed by the relief (or rest) intervals. Additional clothing such as sweat suits should be worn only to keep the body warm. The fewer clothes on warm days the better.

Proper salt and liquid replacement is also of special concern when working in hot environments. Salt taken without adequate water is more detrimental to health then no salt at all.

Measurement brings objectivity along with satisfaction to the exercise workouts.

Progress reflected in increased objective scores sustains interest and promotes motivation.

Also this section will be updated in due time.

"Don't simply outdo the competition, blow them away"

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