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In a message dated 1/18/08 1:22:30 AM, kayoneill@earthlink
> We continue struggling with a Nautilus pullover. People around 5'4"
> must have an additional piece of seating added, while under 5'1"
> requires two layers of seating. One size does not fit all. Even
> average height persons (5'9") have to dink around with the pullover
> since it does not properly fit their arm length. Guys above 6'3" have
> no problem with it. High chair build ups also required for the Lateral
> machine. Good news is the Nautilus ab machine has broken down so we
> can get rid of it.
> The Icarion line of machines is a living nightmare. Looks as if they
> knocked off someone else's appearance of a design without
> understanding the biomechanics in the slightest. We also have a life
> of old LifeLine machines evidencing poor sense of biomechanics.
>
> The solution? Barbells, dumbbells, JC Predator bands, stability balls,
> medicine balls - implementing Scott Abel's hybrid and MET training and
> JC Santana's hybrid ideas.
>
Greetings Ken,
An appropriate? criticism of any type of rotary machine designed as a
function of specific joint center rotation is open to biomechanical scrutiny. That is
-- most machines such as the pullover, pec deck and lateral raise rotate
about a fixed axle. This is a consideration because each of these exercises is a
multi joint movement, i.e., the GH, SC and the CS (as the old song goes "the
arm bone interfaces with the shoulder blade bone -- the shoulder blade bone
interfaces with the collar bone and the collar bone interfaces with the breast
bone").
If one uses an athlete without resistance and traces the arc of movement, at
the elbow for instance, and measures the translation of the center of rotation
of the primary joint, e.g., the glenohumeral -- the possible problem becomes
apparent. A typical primary joint translation is about 2-3+ inches. The rotary
machine severely constrains primary joint translation disrupting the
"natural" rhythm of the involved joints forcing the head of the humerous to interface
with the glenoid cavity in an unnatural relationship. It seems to me that such
conditions unnecessarily stress the cartilage and probably inhibit the full
recruitment of the targeted musculature.
The dysfunctional aspects of said relationships may take years to manifest. I
have an artificial knee and shoulder due, in large part, to the use of poorly
designed equipment *and* improper exercise technique (machines and free
weights). Regardless it makes more sense to perform these exercises with free
weights. The learning curve is not much more difficult with the above exercises
than with machines.
Further more machines also limit the exerciser to one fixed resistance
pattern. If one is to address the changing force capabilities of a fatiguing muscle
then free weights are again much more efficient.
While the advantages of most single rotation/joint machines is moving a
greater population through exercise programs quicker -- the functional advantages
of free weights makes the use of these machines obsolete to any devoted
trainer.
Jerry Telle
Lakewood CO USA
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