High-intensity training is not working out to the extreme. It does not involve lifting insanely heavy weight at a pace that only the best athletes can do. In contrast, high-intensity training involves slower, more controlled movements when lifting weight. In fact, if you want to build muscle and improve tone with the most effective workout, you must understand the importance of incorporating slow paced concentric (movement up) and eccentric (movement down) contractions into your training.

The slow-pace workout method is based on the high-intensity training theory which states that:

It is better to engage in exercise at a higher intensity that requires maximum effort in order to produce biological increases in muscle fiber density, muscle fiber mitochondria and lactic acid tolerance.  By moving slowly, you are subtracting momentum out of your movements that are present with fast repetitions.  Moving slowly also allows you to make sure that both fast and slow twitch muscle fibers are recruited in the contraction instead of only the fast twitch fibers.

Your muscles are also being used in concentric and eccentric movements as opposed to the force being unidirectional.  In addition, you are using postural, or back and abdominal, muscles that are not consistently used during fast movements.  Slow movements, produce an increased amount of lactic acid (the burn) which is a byproduct of muscle metabolism.  Therefore, more burn results in more muscle recruitment.  How does this lead to future growth and an increase in strength that can be generalized to heavier weights?

To understand high-intensity training a few terms must be defined. First, let’s define strength.  Is strength being able to lift as much weight as you can no matter what form or external forces (momentum) you use?  Or, is strength lifting as much weight as you can without correct form and without any external forces such as momentum?  Which method would allow more strength in weaker areas, thus making the individual stronger on a more complete level?  The frame of reference for strength is flawed and must be corrected.  Strength should be defined as the amount of weight one can lift with proper form, on concentric and eccentric movements, and at a controlled pace which reduces the momentum factor.  If power lifters lifted weights with correct form and subtracted momentum, their resistance, or amount of weight that they lift, would be greatly reduced.  However, this would not mean they are “weaker.”

Next, the American College of Sports Medicine’s (ACSM) guidelines for resistance training is that heavy resistance is required to optimally recruit motor units.  This assumes that force is all that counts and not intensity of effort.  This is flawed reasoning. Intensity is defined as a high level of saturation, and in this case would mean maximal motor unit recruitment.  A study done by Behm in the Journal of Strength Conditioning and Research (2002) provides evidence that using heavy resistance does not maximize motor unit recruitment.  The study involved 14 male participants that perform a heavy 5 rep set, moderate 10 rep set and light 20 rep set.  A device which tests muscle inactivation was used.  The hypothesis would be that the 5 rep set there would require more motor units than the other sets.  It turns out that there was no significant difference between the three groups.  They further discussed that the number of repetitions do not matter as long as the last rep involves maximal effort which optimally recruits motor units.  The repetitions leading up to the maximal effort repetition are merely warm up reps.  Again, let me stress that the last repetition is the most important!

Unfortunately, this was a small study and that no conclusions can be made from it. However, it does shine light on the proper way to think about high-intensity training.

Three things to take from all of this about high intensity training:

  • Strength should be defined as the amount of weight that you can lift with the correct form and controlled movements.  Because it is purely you moving the weight instead of momentum or gravity, then that is your true strength.  So, you may not reach 245 lbs. bench with slow movements, but this is irrelevant unless you are a competitive lifter.  However, think how much more impressive it would be to do 225 lbs. 10 times with slow reps…
  • Heavy resistance is not required to optimally recruit motor units.  As long as there is a maximal effort repetition in a range of 5-20 reps then muscle recruitment will be optimal.
  • Because of the increased load in lactic acid, your body will be forced to adapt to this load and find more efficient ways of clearing it to improve endurance.  Being that this is usually the factor that prevents us from continuing with reps, think how beneficial this adaptation could be.

High-intensity training is slow and controlled. Make this your foundation.

Share your experiences with high-intensity training below! Try using slower movements with one of many slow-paced, or 20-minute circuit workouts available on this site.