Supertraining

My name is Susan, I'm 43 years old, and this week is my 12th week in a gym.
Ever. I'm a marathon kayaker and in order to get ready for races I've always
just gone out and paddled. I never set foot in a gym in my entire life until
12 weeks ago. Now I have a kayak coach who has me on a periodization weight
training training program and I've been totally surprised at how much I'm
enjoying it. Please keep in mind that I don't totally understand
"periodization," I just follow her directions and I trust her implicitly and
do exactly what she says. The results are already paying off, I've already
won two races (last week and the week before) and I credit the extra
strength I've gained from weight training for my wins.

I'm now in the "max strength" cycle of periodization. (I started with
"anatomical adaptation" then moved to "hypertrophy" and now am in "max
strength.") The ultimate goal is for me to complete a 70 mile race on
Memorial Day.

My "rest interval" between sets is a full 2 1/2 minutes (it was 2 1/2
minutes for hypertrophy too, but 30 seconds to 1 minute during anatomical
adaptation). I got talking to one of the personal trainers at the gym I go
to and he said I didn't need to wait that long between sets, and he was very
insistent about it. I'm not about to change anything that my coach has me
doing, I totally believe in her, and the results are already showing, but it
got me thinking about rest intervals and their meaning.

My question is: Can you help me understand the "rest interval" between sets,
and what the different lengths of time mean? What does 2 1/2 minutes between
sets mean versus 1 minute between sets? I do not understand the mechanics of
the rest interval and what a longer versus shorter rest interval does for
the body. Any help in understanding rest intervals is appreciated!

Thank you,
Susan Williams 
Just west of Philadelphia, Pennsylvania, USA
http://pennkayaker.com/wiki/members/members.asp?db=MemberPages&o=Lady%20Justice