Posted by: ray porco () on Mon Sep 5 10:39:47 2005

quote you:
>>>“I am not just looking for an answer from Jack … but rather, an answer from anyone who apparently sees the same thing Jack claims he sees.”<<<




Sorry. Won’t touch that with a ten foot pole. I absolutely abhor an attempt by someone to speak for someone else.

BUT,

in answer to what has now become my question:

“If McGwire did not exhibit PLT and Bonds and Sosa do, then why did McGwire have more batspeed?”

I would answer that McGwire DOES exhibit an eccentric – concentric contraction (PLT, if you must) prior to shoulder rotation, not as pronounced as Bonds and Sosa, because it does not have to be.

There is a fine line for proper execution of the stretch shortening cycle in a ballistic event such as the baseball hitting swing. A lot is dependent on our muscle make-up.

There is a threshold at which the stretch load is too great and the golgi tendon organ reflex causes an inhibition of muscle contraction,

and then…

if application of stretch shortening cycle is too gradual/slow, muscles dissipate elastic energy, usually as heat (Cavagna 1977). Elasticity is enhanced if the prestretch and exchange duration is minimal (Komi 1973). Researchers believe the RATE of stretch to be more important than its LENGTH or magnitude. We desire quick prestretch movements over longer, slower ones (Cavagna 1977; Bosco and Komi 1979).


The period during which the muscle changes from an eccentric to a concentric contraction is called the coupling time and the greater force developed is associated with the shortest coupling time…Bosco et al (1982) proposed that individuals with a high percentage of fast twitch fibres in muscles exhibit a maximum plyometric effect when the eccentric phase is short, movement range is small, and coupling time is brief.

ie: McGwire