conditioning effects

["Steph Teeter" <steph@endurance.net>]

This discusssion of heart rates, conditioning, interval training
is great. I thought it might be good to go a little deeper and
look at what the actual effects of conditioning are.

From memory (too lazy to get out the books this morning) here
are some effects of conditioning that come to mind. I'm hoping
some of you out there will elaborate/correct or add more to
this list. It really helps understand why conditioning is important.

1)heart hypertrophy - the heart will actually increase in size.
*question: can the contractile strength be  increased??

2)capillary perfusion - the number of capillaries (tiniest blood
vessels that supply blood to muscle cells) will increase.

3)increased mitochondria - the 'things' in the cells that convert
fuel to ATP (energy)

4)increased muscle mass - more muscle tissue.

5)greater blood vessel network under the skin - better heat
dissipation

6)great bone density - response to concussion/stress

7)stronger, thicker tendons - response to repeated stretching (?)

8)stronger ligaments - ...not sure about conditioning response, I don't
think
ligaments stretch

9)increased # red blood cells - ? not sure about this one

10) stronger nostrils ... ok, this is a little odd, but from what I've read
the lungs and respiratory system can't be conditioned - but the muscles
which control the diameter of the nostrils, and deeper airways can
become stronger, allowing more air to flow into and out of the lungs.

What about the feet - do hoof walls respond to conditioning?

I'm sure I've missed a few - comments and additions are welcome!

Plus as a side note - the cardiovascular system responds quickly to
conditioning - I've read that a horse can be optimally conditioned in
6 months. BUT, the mechanical structures - bone, ligament, tendon,
respond very slowly to conditioning, and it can take several years to
achieve max strength. The years of LSD  are necessary
before the horse can safely (mechanically) tolerate the stress of racing
and advanced conditioning regimes.

Steph