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With so many weight training systems to choose from, it can be difficult and confusing trying to determine which ones are worth investing your time and energy in, and which ones to disregard; especially when some of those worth forgetting have been popularised by some well known individuals or magazines.

Seven Key Principles of Weight Training

The seven key principles behind weight training, and using them as assessment criteria, validate the effectiveness of three of the more common training systems include:

  1. Individual Difference: this principle acknowledges that we all have heterogeneous genetic blueprints. Consequently, we all respond similarly to the stimulus of exercise, yet the rate and magnitude of those adaptations is what varies from person to person: some people respond quickly, whilst others respond slowly.
  2. The Overcompensation Principle: muscle fibres hypertrophy, calluses develop in response to friction and injured tissue can scar. These are examples of overcompensation for a stress response. Essentially, it is a survival mechanism built into the species to promote sustainability.
  3. The Overload Principle: in order to ensure continued adaptations, whether it is size, strength, power or endurance, you must exercise at an intensity that is greater than that normally encountered. Doing the same workout with the same load, reps, sets and rest periods will ensure the body will not adapt beyond that to which it has already adapted.
  4. The Said Principle: is the way in which your body adapts to a given training stimulus. The SAID (specific adaptations to imposed demands) principle is uncompromising in its highly researched tenet governing the law of specificity. For example, if you want to develop power, then engaging in plyometric training would best facilitate the desired adaptations. In contrast, if muscular endurance of long duration was desired, then low intensity high volume sub-maximal continuous contractionswould be the better choice.
  5. The Use / Disuse Principle: very simply, ‘use it or lose it’. Also known as the principle of reversibility, states that upon the cessation of training, any acquired adaptations will slowly deteriorate.
  6. The Specificity Principle: similar to the SAID principle, this principle states that in order to acquire specific adaptations, the training stimulus must replicate the adaptation required. For example, if you want to improve your running, then run. Although cycling, swimming and other aerobic based modalities would illicit a positive cross-trainingeffect, and would be great forms of active recovery, they would do little to actually improve your run times. The key difference between the SAID and specificity principles is that the specificity principle encompasses neurological and functional adaptations.
  7. The Gas Principle: gas is the acronym for general adaptation syndrome, which is comprised of three stages:
  • Stage 1 is the alarm stage, which is caused by the application of an intense training stimulus (overload principle).
  • Stage 2 is the resistance stage, when muscles adapt in order to resist the stressors more efficiently (overcompensation, said & use / disuse principles).
  • Stage 3 is the exhaustion stage, in which if stress was continually applied, reserves would be exhausted and cessation of training would result. In resistance training circles, the gas law states that periods of low intensity or complete rest must follow periods of high intensity training. The reason being that the stressors applied to the muscular system have caused structural damage. In order to facilitate recovery, and subsequent improvement, the body must be afforded the opportunity to regenerate. If this opportunity is not afforded, then continued trauma will result in overtraining, decreased performance and possible injury.

Other principles do exist, but the seven listed are the most accepted and have the support of the scientific community. We will now identify and discuss three of the more common training systems, which are as follows:

  1. Positions of flexion (pof);
  2. Heavy duty (hd); and
  3. High intensity training (hit).

Positions of Flexion (POF)

Is a training method proposed by Steve Holman from ironman magazine. The claim is that pof hits a given muscle from three angles and therefore training it through a full range of motion (rom). For example, a typical pof biceps workout may include barbell bicep curls, incline dumbbell curls and concentration curls. The arc of the biceps is from the fully extended arm position and up towards the head. Pof has you hitting the biceps in three positions along that arc. The incline dumbbell curls stretch position is the bottom of the arc, the barbell curls stretch position is the middle of the arc and the concentration curls is the top of the arc. This is supposed to result in better adaptations. The conduct proposed is to perform two warm up sets at 50 and 70 percent one rep-max of the first exercise (barbell curls) and one to two work sets of the other two movements. So, does this confirm to the known principles?


Confirmation to known principles

1. Pof hits the muscle from three angles training it through a full rom.

No noted research to support the claim.

2. A total of 6 sets are performed.

Principle of individual difference is violated. No mention of volume, frequency, rep speed etc.

Heavy Duty Training (HD)

Is a concept credited to Mike Mentzer, a famous bodybuilder of the eighties. The claim is to perform as many warm-up sets as required, followed by only one actual work set.


Confirmation to known principles

1. Essential that you don’t select a weight that is so light that the last rep within the specified range (i.e. 6-10) requires anything less than 100 percent effort.

No research is noted that supports the claim that each set must be taken to muscular failure.

2. Fewer than six reps will not sufficiently tax your reserves, whilst more than 12 reps could cause you to terminate the set prior to muscular failure due to cardio respiratory failure.


Principle of individual difference is violated. No research indicating that 6 or 12 are required for the adaptations to occur. In contrast, research suggests that one can benefit from less than 6 reps and more than 12 reps. This claim violates the said principle.

3. It is not necessary to ingest an abundance of calories to facilitate hypertrophy. Building muscle is possible for limited periods on a starvation diet.

No research to substantiate this claim. The claim, although not in violation of the seven key principles, by suggesting that hypertrophy is possible on a starvation diet ultimately does violate them all.

4. All out effort of the hd high intensity variety requires intense motivation and physical and mental courage. Only a person fuelled by a strong, almost overwhelming sense of purpose and meaning will be able to train hd style.

Not everyone 1) is able to train this way, 2) wants to train this way, or 3) should train this way. Hd may work for some and not for others: placing it in violation of the said and individual difference principles.

5. Train each muscle group as infrequently as possible.

Illogical! One’s desires do not control optimal training frequency. Rather, recuperative ability does; consequently, this is in violation of the individual difference, the use / disuse and gas principles.

High Intensity Training (HIT)

Very similar to HD, hit isn’t much different, just a few additional and minor adjustments.


Confirmation to known principles

1. Train with a high level of intensity: characterised by performing an exercise to concentric muscular failure. Ensure you can no longer raise the weight at all otherwise little or no gains in size or strength will result. Once concentric failure is reached, complete additional 3 to 5 eccentric reps to ensure sufficient overload has been applied.

Yes, going to failure constitutes intensity; however, training to failure is not a prerequisite for adaptations. Specific training objectives sometimes mitigate going to failure (e.g. Speed training); consequently, the said & gas principles have been violated.

2. Attempt to increase the resistance, or the reps performed every workout.

The said & gas principles are violated. Sometimes lighter weights are required and sometimes heavier weights are required: depending on what training phase you are in.

3. Perform 1 to 3 sets of each exercise. Research suggests that no significant difference exists between performing one, two or three sets of an exercise.



Research consistently suggests that significant gains can be made with three sets or more as opposed to one. Those with more fast twitch fibres require less training volume and frequency than those with predominantly slow twitch fibres. The overload & said principle are not being employed maximally and the principle of individual difference is violated.

4. Strength train for no longer than one hour. If you are training with the required intensity, you cannot exercise for long periods of time. Training with minimal recovery time between exercises will elicit a metabolic conditioning effect that cannot be achieved via traditional multiple set programs.

This violates the overcompensation, specificity & said principles. People are different!

5. Emphasise the major muscles. The focal point for most of your exercises should be your major muscle groups.

Sometimes it is important for athletes to train lagging body parts first. This claim is in violation of the specificity & said principles.

6. Always train your muscles from largest to smallest.

Again, in violation of the specificity & said principles.

7. Strength train 2 to 3 times per week on non-consecutive days. 48 to 72 hours is required for a muscle to recover sufficiently from a strength workout. 48 hours is required to replenish carbohydrate stores. Performing any more than three sessions per week can be counterproductive due to a catabolic effect.

Each muscle has its own recuperative ability and subsequent recovery time. Sometimes 48-72 hours is sufficient, other times it is not. Main points to remember are:

·   large muscles take longer to recover than small ones,

  • fast twitch muscles take longer to recover than slow twitch fibres,
  • men recover faster than women,
  • you recover faster from low intensity training than high intensity training, and
  • age decreases recovery time.

Many athletes train twice or more per day. People have different recuperative abilities and as such, the principles of individual difference, said, gas & specificity are violated.

Many other training systems exist, such as: big beyond belief, hardgainers system, German volume training, body contract, bigger faster stronger, serious growth, Bulgarian power burst training, power factor training, supersquats training, rest-pause and superslow training. To simplify everything spoken about thus far, and to make it easier for you to determine whether or not a particular training system adheres to the seven key principles, read on:

  • The fact that you are training (1) Ensures the overcompensation principle is being applied, (2) If you train regularly that the use / disuse principle is applied, and (3) Weight training is the best method of increasing strength and size, therefore, the specificity principle is applied.
  • If training is periodised, then the gas and said principles are applied.
  • If you continually strive to progressively place greater stress on your muscles than what they are accustomed to, then the progressive overload principle is applied.
  • When designing your program, you must consider your individual strengths and weaknesses: this will ensure that the principle of individual difference is adhered to.

The Final Word on Weight Training Principles

The most effective method, rather than a particular training system to facilitate your training goals is periodisation. Various periodised models exist, with the two most common being the step overload and wave models. As always, which system is best has been, and will continue to be heavily debated.

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