Re: twitching muscles.

[CMKSAGEHIL <CMKSAGEHIL@aol.com>]

In a message dated 98-04-29 18:16:33 EDT, elsie@calweb.com writes:

<< Do those muscles change with conditioning, or is it something
 that the horse is born with and that's that? >>

Some fibers are fast-twitch, some are slow-twitch, and some are
intermediate--the first two are what they are, but the intermediate ones can
be "recruited" to function like slow-twitch with conditioning.  Horses are
born with certain percentages of each type, and that is heritable, but within
the limits of what nature gave them, they can still improve their ability to
do either fast-twitch or slow-twitch work by influencing those intermediate
fibers.  Tom Ivers could explain better, but hope that helps.

Heidi