Exercise Science, LLC

Personal Training and Rehabilitation, New Orleans, LA.


Different Definitions of Intensity

I was recently questioned about the various ways I defined intensity. This was originally written on August 5th, 2004 on my Clinical Exercise Tech Yahoo Group / Email list.
I was recently questioned about the various ways I defined intensity. This was originally written on August 5th, 2004 on my Clinical Exercise Tech Yahoo Group / Email list.

Failure is not the goal. Improvement (strength increase) is the goal. In
order for improvement to occur, we need to apply a higher absolute intensity
(more on this later) stimulus to the body than what it is accustomed and
balance that stimulus with a specific amount of recovery. With a beginning
subject, almost any combination of load, TUL, fatigue, etc. will probably be
a higher absolute intensity stimulus than what they are accustomed. As the
load increases for a specified TUL, more muscle fatigue will result. At some
point, as the load increases, muscle failure will eventually be reached.
Going to failure does not ensure a higher absolute intensity stimulus. It
merely means that one has done everything to achieve a higher
absolute intensity stimulus.

Let me give an example:

Given everything else is equal (repetition speed, etc.), if you go to the
gym every week for a year and lift 100 lbs on chest press for 1 minute
(reaching failure), but do not get stronger (for whatever reason), you have
not applied a higher absolutely intensity stimulus. There was no increase
in load or TUL. Therefore, the absolute intensity was the same, even though
your relative intensity is 100%.

Yes. Reaching muscle failure ensures that the subject has done everything
possible to achieve a higher absolute intensity stimulus. Further, I think
some trainers wrongly focus too much on reaching failure and not enough on
improvement. I often see this with some of the trainers at our facility.

The problem is that the word intensity can be ambiguous. A few years ago, I
made this distinction on the other email list (before we were ever a Yahoo
group). But, it is probably worth reviewing. In order to be more specific
with our language, we may want to consider adopting the following
terminology, until a more descriptive expression is found.

Relative intensity: ­ This defines the intensity of effort. For example,
when you first start a training career, you walk into the gym and lift 100
lbs on chest press failing at 2 minutes. Over the course of a year, you
become stronger, lifting 200 lbs failing at 2 minutes. Your relative
intensity is exactly the same (100% of maximum effort). However, your
absolute intensity is much higher (two times) with the latter.

Absolute intensity: ­ This can be defined as the total amount of stress
applied to the organism during a training session. In the above example,
the second scenario is twice the absolute intensity.

Load intensity: ­ This defines the percentage of maximum load. In research,
this is generally what the scientists refer to as intensity (80% of the 1RM
for example). Most of us do not use a percentage of the 1RM for training.
However, when discussing exercise research, it may be more descriptive to
refer to this as load intensity or intensity of load.

This is something I wrote more recently:

I defined intensity three ways. Researchers usually define intensity as the percentage of 1 RM. I called this intensity of load. The second definition I used, I referred to as relative intensity or intensity of effort. This is the way we usually describe intensity, hence going to momentary muscular failure would equal 100% intensity of effort for that exercise. I'm not sure that definition would necessarily be appropriate for research, unfortunately. In the research literature, subjects usually continue the exercise until "volitional fatigue", meaning the subjects stop the exercise when they want. They may be encouraged to continue until momentary muscular failure. However, they can not be forced. I doubt this would pass a human subjects comity. The third way I defined intensity is absolute intensity. This is what I consider most important. Absolute intensity is the total amount of stress that the organism can tolerate. For example, if a subject starts out lifting 100 lbs on chest press, yet over time increases to lifting 300 lbs (all other variables being equal), that subject has effectively tripled the absolute intensity for that exercise.


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