What is intensity? How is it defined? Let us examine this using two competing definitions currently used in the field of resistance
training. In brief, Arthur Jones defined intensity as the percentage of momentary ability being exerted by the trainee. The
NSCA organization is defining it as the amount of 1RM used in a set. Comparing and contrasting the Jonesian definition to
the NCSA view renders the following analysis: If you are attempting 1 rep with 100% 1RM you exerting a 100% momentary effort.
Both definitions converge at this point in that they both state that the trainee in this example are training with 100% intensity.
Divergence occurs, however, when you look at other cases. A situation where the trainee is attempting 8 repetitions with 80%
of 1RM gives, in the Jones definition, 100% intensity. However, according to the NCSA view this would not be. To examine how
this discrepancy occurs, lets examine the situation further. Compare two trainees, one doing attempting the above 8 repetitions
with 80% of 1RM with another trainee attempting 2 reps with 90% of 1 RM. The first trainee would be exerting 100% of momentary
ability on the last reps and reaching, according to the Jones definition, 100% intensity. The second trainee using a heavier
weight, would, according to the NCSA guidelines be training with higher intensity. But, unless he is an extreme case on the
neurological efficiency scale, his effort-even on the second, i.e., last rep would not be a maximum effort, as he likely would
have at least another 2-3 reps in him. Thus, even though he is using a higher weight the fact that he does not attempt those
two repetitions, and does not approach a maximum effort, means that the effort is not as intense as the previous trainee who
does make a maximum effort.
To further elaborate where the discrepancy occurs, compare the %RM scale method used by the NCSA versus the Jonesian approach
at various percentages:
50% 60% 70% 80% 90%
25 reps 20 reps 12 reps 8 reps 4 reps
2 reps 2 reps 2 reps 2 reps 2 reps
Comparing from the above table the trainees from the 90% and 2 reps versus the 80% at 8 reps from the above examples we
see according to the NCSA definition that the first trainee is training at a higher intensity. (Note- the number of reps is
the same for all the percentage columns for the second case- since the NCSA is only considering %of RM as the defining factor
Comparing the 60% trainee doing 2 reps versus the 50% trainee doing 25 reps would, according to these guidelines, illustrate
quite graphically what is wrong with the NCSA definition. The trainee doing 2 reps at 60% is exerting nowhere near an maximum
effort- in fact he isnt working hard at all, and would likely give a response to a perceived effort question as fairly easy,
which, of course it would be. Compare and contrast this with the trainee from the 50% table doing 25 reps. According to the
NCSA guidelines he is training at a lower intensity. However, despite the fact that his initial repetitions would be easier
than the first trainees would, the last few repetitions would be quite hard, and the last repetitions almost impossible to
complete. The last repetition attempted by the first trainee would be nowhere near impossible and their response to a perceived
effort question would likely tell you that they did not experience anything near a maximum perceived effort. In this case
it is quite obvious that the number of repetitions attempted with a given weight has an effect on the intensity of exercise.
What kind of effect does it have? The farther the trainee progresses into the set, the more of his momentary ability he uses
up- he makes a deep inroad into his momentary ability. The first trainee made very little inroad into his momentary ability,
while the second trainee, although training with a lighter weight made a considerable inroad into his momentary ability. In
fact, so much so, that the last repetitions, although attempted with what could be said to be a fairly light weight, was almost
impossible for him to complete. Intensity is clearly related to the degree of inroad one is making into his momentary ability.
The more inroad that is made with a given weight, the higher the intensity. Applying this definition to the original too examples
the trainees using 10% of a 1RM and attempting 1 repetitions is making a 10% inroad into his momentary ability with that particular
weight. But so is the second trainee who is attempting 8 repetitions with the 80% 1 RM weight.
In conclusion, the intensity can be defined as amount of a given inroad into momentary ability made with a given weight
or resistance. A 100% inroad into momentary ability would be 100% intensity. I.e., a point of muscular failure. A 50% inroad
would be 50% intensity, i.e. half of the trainees momentary ability is used up. It should be mentioned here, if it is not
already obvious, that inroad as defined here is not the same as used in the Jonesian camp, when it is used in the context
of inroad into recovery ability. This is a separate, albeit related aspect. It should also be pointed out that since we are
talking about any given weight, the 1RM factor falls out of the equation at this point. Since we are examining in each case
the degree of inroad into momentary ability with a particular resistance, the resistance per see, i.e. the percentage of 1RM
cannot be the defining characteristic, but is, in fact, only an aspect of training intensity. We are then left with the percentage
of momentary ability available- the amount of inroad made being the key factor, which determines how much momentary ability,
is left. The greater the inroad, the less momentary ability is left.
To determine if this definition is indeed, operational, applying it to the examples above renders the conclusive evidence
that the trainee who are making the greatest inroad with a particular weight- resistance- are the trainees training with the
In matters of practical application, and to possibly forestall or answer objections to the above discussion that may occur,
lets revisit two of the examples above. The Jonesian oriented camp might object to the 100% 1 RM examples as being insufficient
in duration to create a real inroad and it is. But we are strictly defining the concept of intensity. Duration is a separate,
albeit related concept.
The NSCA camp might object to the last example as being an extreme comparison- and it is. But, although no two trainees
are likely to train in the manner mentioned in that example-it was use to clarify and illustrate the concept of intensity,
not to make training prescriptions or recommendations.