ISOMETRIC PARADOX


PUZZLE & PARADOX 123

If the theories about 30-60 seconds minimum of muscle tension time to maximise
muscle development are correct, then why does sustained isometric training
then not produce the best results of all? This would also eliminate any
arguments about the instrusion of rest intervals during the transition phases
between eccentric and concentric actions in any exercise.

If this remark induces some folk to state that TUT (Time Under Tension) works
best under dynamic conditions, then we will have to say: "Aha, doesn't this
mean that continuous tension is not such a good idea and that some brief
transitional 'rest' intervals are necessary?". Or does it mean that one
cannot exclude all eccentric activity and hope for hypertrophy? Then again,
some will add that research shows that muscle growth does indeed occur with
concentric training alone.

We cannot discard the isometric paradox on the grounds of the tension not
being great enough, since research consistently shows that maximal isometric
action produces greater tension than maximal concentric action, though not as
much as maximal eccentrics.

In an earlier post I suggested that the product of tension time and average
tension (TUT x Taver) in any given exercise may be a more useful measure of
training effect than TUT alone - if some folk consider such measures to be
necessary. If this is more acceptable, then this equation would produce a
larger value for sustained intense isometric action than for most dynamic
exercises. Yet, this still does not explain why isometrics do not produce
maximal hypertrophy.

If holding an isometric contraction for 30-60 seconds proves to be a bit too
challenging, then one can use oscillating isometrics (see Siff & Verkhoshansky
"Supertraining" 1998) with little ballistic up and down pulsations to
maintain muscle tension for longer periods and offer all the training benefits
of isometric and quasi-isometric action.

There are several other scientific and technical points which could be added,
but this suffices to make us wonder why sustained long tension times with
isometric exercise does not produce the same hypertrophy as dynamic exercise.
Maybe it does, but there are so few people around who have predominantly
isometric workouts that we never hear about it or have much research done on
isometrics.

What do all of you think?

Dr Mel C Siff
Littleton, CO, USA
mcsiff@aol.com