>When you say aerobic exercise, are you including high intensity interval
>sprints.  I thought that interval training could build muscle and increase
>fat loss.

Hmmm, maybe a trick question... I used to coach racing cyclists, and many
would insist that they could become stronger just by climbing steep hills
in high gears, or, as you suggest, by sprinting. They would believe
anything that would let them avoid weight training:) The ones who went to
the gym and built muscle with weights, or who did deliberately explosive
training such as plyometrics, jump squats, and other rebound-type lifts,
became stronger much faster. Training on the bike, or on the track, can
build a little muscle and a moderate amount of specific reflex training
which can improve performance, but this is, in my experience, most
effective when the muscle and strength has been acheived using weights.
That's why they invented weights - they make you strong in a very efficient
way, and darn near every sport, Olympic and professional, makes use of
weight training to optimize performance.

Muscle mass increased by sprinting will of course increase caloric needs,
as will the effort of training in general, and so there can be a resultant
fat loss. You can get much more rapid increases with weights, of course.

Now, addressing your first question: Sprints and intervals are, by
definition, anaerobic exercise, the benefits of which are gained by
systematically and repeatedly going well past the "aerobic threshold" and
then recovering to a specified degree. So, no, by aerobics I'm talking
about distance running, Stairmaster, treadmill, stationary cycling, rowing
machine, and all the other ways we have devised to simulate continually
running for our lives from predators and elevating our cortisol levels
unnaturally day after day. This stuff can be dangerous, addictive, and fits
right into the whole hyperinsulinemia/high carb syndrome. I feel sprinting
is not only more natural to humans, in the sense of how they might have
spent their time as hunter/gatherers, but also, a nice use and proof of
one's fitness and actual, practical, stregth. But, heck, that's just me...

ginny and Tomo, bulky by nature and by design

All stunts performed without a net!