by Arthur Jones
From IRONMAN March 1973, Volume 32 Number 4, visit www.ironmanmagazine.com
Exercise is capable of producing a wide variety of results - increases in strength, improvements
in flexibility, greater cardiovascular ability (or "condition") and a number of other physical
improvements. All of which factors are important for even a normal degree of health, and
particularly important for athletes.
In this article, however, attention will be directed towards only two of the possible results of
exercise - the development of maximum strength, and the simultaneous production of maximum
flexibility. These two factors are unavoidably linked by the simple fact that the best program of
exercises designed to produce strength will also promote flexibility - since stretching movements
are an absolute requirement for building maximum strength, increased flexibility is a very
valuable by product of a properly designed strength program.
But it should be noted that it is easily possible increase flexibility while doing little or nothing in
the way of building strength.
And it should also be understood that in arty types of exercises will produce at least some degree
of increased strength while doing nothing in the way of improving flexibility.
For the purpose of producing maximum strength, a muscle must be worked against resistance
throughout its full range of possible movement. Resistance must be available in the position of
full contraction - and resistance is also required in the position of full extension. Unfortunately,
most types of exercise provide no resistance at either end of the movement - the unavoidable
results being that strength is increased only during the mid-range of possible movement, and that
flexibility is not improved at all.
A recently developed and highly advertised method of training called "isokinetics" by one
company. and "isonetics" by another company, is an example of a type of exercise that involves
only the mid-range of movement and does absolutely nothing in the way of improving flexibility.
Such exercises are based upon a "speed limiting" device of one type or another - thus resistance
is provided only when movement is occurring. When movement stops, the resistance ceases -
A moment's consideration makes it obvious that full-range exercise is impossible with
isokinetics. Upon reaching a position of full contraction at the end of the exercise. Additional
movement is impossible - and the resistance instantly ceases. Since the availability of such
resistance is unavoidably linked to movement. a lack of movement equates a total lack of
resistance - and without resistance there is no exercise.
And - at the start of the exercise, in the extended position, there is no available resistance to
provide the essential "pre-stretching" which is so valuable for both strength building and
"Pre-stretching" of an extended muscle at the start of an exercise movement is provided by
negative resistance - and the speed-limiting types of exercise devices have no negative resistance.
Barbells and most other types of exercise devices are based upon negative resistance - when
lifting a barbell you are performing positive work against negative resistance, you are pulling
"up" and the barbell is providing resistance against your movement by pulling "down."
But a barbell also provides negative work. At the top of a movement, after the weight has been
raised as high as possible, the barbell must be lowered back to the starting position - and you are
performing negative work while lowering the barbell.
For the purpose of building strength, such LOWERING of weight is far more important than
If you remove negative resistance from an exercise - as the isokinetic people have done - you
unavoidably remove a very large part of the strength building characteristics of the exercise at the
same time, and you utterly destroy the flexibility promoting factors. Such exercise - in spite of
the claims by its promoters - will do very little in the way of building strength. and absolutely
nothing in the way of improving flexibility.
The makers of such devices also point out that isokinetic exercises produce little or nothing in
the way of muscular soreness. And in this instance, at least, their claim is correct; for the simple
reason that isokinetic exercises do not provide the stretching that produces muscular soreness in a
previously untrained individual.
When a muscle is first exposed to an actually full range movement against resistance, the
attachments will be forced into a position beyond the range of average movement - and if part of
the muscular structure is disproportionately weak, then the weak area will become sore as a
But it will also become stronger as a result - and it will never become stronger until and unless it
is exposed to such resistance.
With regular training, muscular soreness does not continue - and it does not return. Soreness
occurs only at first, as a result of the first one or two training periods - then it quickly disappears,
and it will not return so long as regular training continues.
Positive work (or "concentric"work), as provided by isokinetic devices, involves only part of a
muscular structure - and does absolutely nothing for the most important areas of movement, the
fully contracted position and the fully extended position.
Negative work (or "eccentric" work), as provided by a barbell or a Nautilus Machine, exercises a
far larger part of he total muscular structure - and does improve flexibility; and such exercises
will produce muscular soreness at first - soreness being the unavoidable price of worthwhile
But an extreme degree of muscular soreness is not a requirement - and if a "break-in" program of
fairly light movements is followed for a period of a week at the start of training, then an
uncomfortable degree of soreness will be avoided.
And after such a break-in program, muscular soreness will vanish and will not return - regardless
of the intensity of training.
However, even a well trained individual may experience some degree of muscular soreness if he
changes his exercises. Adding a new exercise to his program may involve stretching in an area
of movement that is new even to an experienced trainee - and if so, then some degree of soreness
can be expected as a result of the first one or two training periods.
So even a well conditioned trainee should break-in gradually when adding a new exercise to his
program. But if a trainee has been using a particular exercise for two or three weeks, or longer -
then it is almost impossible to make him sore as a result of that exercise, and he certainly will not
become sore from his regular workouts, regardless of the intensity of the workouts.
Isokinetic devices provide "positive only" resistance - barbells and Nautilus Machines provide
both positive and negative resistance. With an isokinetic device you are performing concentric
contractions - with a barbell or Nautilus Machine you perform both concentric and eccentric
Careful research clearly proves that eccentric contractions (negative exercises) are of far greater
value for the purpose of building strength - when large groups of previously untrained individuals
were trained with negative only exercises the results were far better than those produced by a
similar group trained with positive only exercises.
The cause and effect factors involved in exercise are actually quite simple strength increases are
produced in proportion to the "intensity" of an exercise.
"Intensity" is best defined as "percentage of momentary ability."
If you are capable of bench pressing 300 pounds, and you press only 100 pounds - then the
intensity is low.
But if you are capable of 300 pounds, and you use 300 pounds - then the intensity is high.
No amount of low intensity training will produce much in the way of increases in strength. But if
the intensity is high, then a very small amount of training will quickly produce maximum
The isokinetics people also claim that such training provides the highest possible intensity - a
claim which is simply not true. But it is true that isokinetic exercises produce maximum FORCE
- which is neither necessary nor desirable.
Intensity produces RESULTS - force causes INJURIES.
A muscle is stimulated to grow only when it is exposed to an amount of resistance that is very
close to its maximum level of momentary ability.
Injuries are caused when an amount of force is produced which exceeds the momentary
"breaking strength" of some part of the muscular structure.
So the intensity of exercise must be as high as possible -but the force must be as low as possible.
And it is easily possible to provide both maximum intensity and very little force at the same time.
EMG measurements of the electrical activity that occurs during muscular work clearly prove that
the intensity of exercise is much higher during an eccentric contraction, while performing
negative work, when lowering a weight.
And it is also obvious that the force is lower during negative work.
Thus negative exercises provide both higher intensity and lower force.
Negative exercises do more in the way of stimulating strength increases and do so while
involving very little force - so negative exercises are both more productive and far safer.
If a 100 pound barbell is resting on a scale. the scale will indicate the full weight - proving that
the barbell is producing 100 pounds of "downwards" force.
And if you grip the barbell and produce 50 pounds of "upwards" force, the scale will then
indicate only 50 pounds - proving that you are producing 50 pounds of force. But the barbell will
And if you then produce 100 pounds of .'upwards" force, the scale will read zero. But the barbell
still won't move.
In order to move the barbell "upwards," you must produce force in excess of 100 pounds - and if
such movement is occurring. then this is clear proof that you are producing more than 100
pounds of force.
But if, instead of lifting the barbell, somebody handed you the weight in the "top" position, and if
you simply lowered it instead of raising it, then it is also obvious that you would not be
producing 100 pounds of force.
If you made no attempt to stop the "downwards" movement, and no attempt to reverse the
movement. then you would be producing less than 100 pounds of force.
However, if you did stop the movement, then you would be producing exactly 100 pounds of
force - and if you reversed the movement, then you would be producing more than 100 pounds of
Obviously, then, the movement should never be stopped and should never. be reversed - a
continuous but slow "downwards" movement should be permitted. Your muscles will thus be
delaying the movement but will never stop it.
A clear understanding of the above simple points should make it obvious that this style of
exercise will produce very little force, and will thus be far safer than any other style of exercise
but what about the all important factor of intensity?
If the weight is properly selected, then the intensity will be far higher in such exercises.
During the first two or three repetitions, it should be possible for the trainee to easily reverse the
movement and move the weight in a "positive" (upwards) direction - but no attempt to do so
should be made.
Then, during the next two or three repetitions, it should be possible to stop the movement -but no
attempt to do so should be made.
Only after several repetitions have been performed with no attempt to stop or reverse the
movement - only after it becomes momentarily impossible to stop or reverse the movement -
only then should the trainee even attempt to stop the movement.
In effect, if you can reverse the movement, don't try - and if you can even stop the movement,
But after it becomes impossible to reverse or stop the movement - then try as hard as you can.
Such a style of training will result in an intensity that is utterly impossible to duplicate while
training with positive movements - and will do so while involving very little in the way of force.
The above points are not a matter of "opinion" - and they are not unproved "theory" - instead.
they are simple, undeniable, physical laws. The reader is, of course, perfectly free to form any
opinion that he chooses - but I will remind you that you can NOT change the laws of physics to
Which is exactly what the makers of isokinetic machines are trying to do. Having REMOVED
the most important part of exercise - the NEGATIVE RESISTANCE - they are now pointing
with claimed pride to the fact that their devices provide ?positive only" exercise, involve
"eccentric only" contractions.
Failing to understand the actual factors involved, many people will be misled into believing the
claims about isokinetic exercises - which is unfortunate. to say the least, because the result will
be that many people will thus be led in exactly the wrong direction.
No other result is even possible since the truth of the matter is that isokinetic exercises are THE
WORST TYPE OF EXERCISES. The least productive type of exercise - and the most
dangerous type of exercise.
IF NO OTHER TYPE OF EXERCISE WAS AVAILABLE - then, AND ONLY THEN,
isokinetic exercises might be worth considering. But it happens that we do have a choice in the
matter - and it is utterly ridiculous to use the WORST type of exercise when it is possible to use
the BEST type of exercise.
For the last several months, we have had all of our trainees on a program of exercises strictly
limited to NEGATIVE ONLY resistance - and the results have been by far the best that we have
And in the meantime, we have been telling everybody that we talk to about the enormous
advantages of "negative only" resistance. And as a result of this spreading knowledge, literally
thousands of people are now training in this fashion - and from every single report that we have
received so far, all of these people are producing faster gains than they ever did before from any
other style of training.
The simple logic, the physical laws, the theory, the research results, and the practical experience
all indicate exactly the same thing . . . THE BEST TYPE OF EXERCISE is NEGATIVE ONLY.
If you have questions about exactly "how" to make use of this extremely productive form of
training, call us any one of several people on the Nautilus staff can and will answer your
A bit later in time, we will distribute a free book on the subject - a book that will clearly detail a
number of workouts that can be followed, workouts using conventional training equipment or
Hundreds of people have called to ask me. "how does this knowledge effect the value of Nautilus
And the simple truth is that it IMPROVES the value of Nautilus equipment - it provides a better
way of using the most productive equipment ever built. It changes nothing but the results -
giving even better results than we were producing earlier. Workout times are reduced even more
- and results are produced even faster. Many of our ?hard gaining" trainees are now growing at a
rapid pace for the first time in their lives.
Casey Viator is now bigger than he has ever been before at the same bodyweight - his muscular
measurements and strength are at a level equal to the best in his life, but at a 15 pound lower
bodyweight. When we get him back to his highest previous bodyweight, I almost shudder to
think what his measurements will then be but it is already obvious that they will be far larger than
During a phone conversation with Boyer Coe last night, he told me that he has gained 5 pounds
of muscular bodyweight from two weeks of negative only training, using a very brief program
that I suggested to him. He also said that his training partner has gained 12 pounds of muscular
weight from the same negative only workouts - in two weeks.
Our office manager, Tim Cook, has gained more than two inches on his arms from less than two
months of negative only workouts - workouts so brief that they are almost ridiculous. Workouts
involving only ONE SET of each of ten exercises - workouts that can be, and should be, finished
in about ten minutes.
Some people - probably quite a few people will make the same old mistake of assuming that
MORE is BETTER. Which certainly is NOT true. Brief workouts are a requirement - so if you
make the mistake of training more - then you will gain less. And if you train too much, then you
won't gain at all.
And do not make the gross mistake of ADDING such negative only training to your regular
workouts - instead, use this training in place of your regular workout. To the maximum degree
possible, totally ELIMINATE positive work from your training.
Positive exercises should be used only about once each third week - and then only for the
purpose of judging your progress and maintaining your form.
I would suggest that you follow a program of eight negative only workouts and then one positive-
negative (normal) workout.
During the first week, train three times - negative only. During the second week, also train three
times - negative only.
But during the third week, use two negative only workouts - and then one regular workout.
Then back to another three week cycle of eight negative only workouts followed by one regular
Some people will adopt a "wait and see" attitude in regard to this information -but by so doing
they will be denying themselves the great value of already established, clearly proven, undeniable
The wise reader should clearly understand that I don't care how you train -it makes no slightest
difference to me whether you train right or wrong. So I pass this information along only in a
sincere attempt to make the simple truth as widely known as possible - in the end, the truth will
be known, regardless of what I say and regardless of what others may say or believe. But if you
are wise enough to conduct a few simple tests for yourself - then you can take advantage of the
truth now, while some other people are still wondering what to do. Suit yourself.