From: harry@cv.hp.com (Harry Phinney)
Subject: Re: Building Muscle
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
X-Newsreader: Tin 1.1 PL4
Distribution: usa
Date: Wed, 30 Dec 1992 20:31:02 GMT

krw@cbnewsk.cb.att.com (keith.r.smith) writes:
: I respectfully submit that 24 rep sets are not going to bring you anywhere
: near aerobic failure except in cases of doing large-muscle exercises such
: as deadlifts, squats, or power cleans and other work on that order.

I'll go a bit further.  Regardless of the exercise, 24 reps isn't going
to be "aerobic" if "aerobic" is defined as relying on the aerobic
metabolisms for the majority of the energy used in the exercise.  The
aerobic metabolisms can only be the major contributors if the exercise
lasts for more than several minutes without pause.  For shorter efforts
the anaerobic metabolisms (both ATP/CP and lactic carbohydrate) can
provide much more power than the aerobic mechanisms.

: I would also use the example of bicycle racers. Be they big or small, they
: all have "hellified" thighs. I wonder how many "reps" a racing cyclist does
: in a typical road workout.

For a 4-hour ride, figure around 90rpm*240min ~= 20,000

: I also wonder how many "reps" he/she does when
: scaling a tough hill.

Let's see, maybe 70rpm*5min ~= 350.

: Mind you, these folx must stay below the anaerobic
: threshold during a workout (or a race, for that matter), because if the legs
: pump up, the legs will quit.

I have to doubt you've ever ridden in a massed start bicycle race.  A
bicycle racer has to be prepared to go well beyond AT in order to
maintain contact with the group.  Staying below one's AT does no good if
you lose the draft of the bunch.  The top portion of virtually every
climb is done at a pace beyond AT, and not infrequently beyond VO2max.

: The aerobic threshold kicks in when the
: heart/lungs can no longer keep up with the work that the muscles are trying
: to do.

It is not clear that the heart or lungs by themselves define the AT.
The limiting factors for AT and for VO2max are the subject of quite a
bit of current research.  A theory I like is that each stage of O2
transport and utilization - lungs, blood chemistry for both affinity and
disassociation with O2, capillaries and transport to the cells, and
metabolisms within the cells - are analogous to resistors in series.
Improving any one element improves the total throughput much like
reducing one resistor in a chain.

: One does not come anywhere near this in upper body work unless they
: are doing well-over-50-rep sets.

I'm not sure I've followed the arguments well enough to know whether I
agree or disagree with this:-) One is not likely to tax the aerobic
metabolisms significantly unless doing truly hellish numbers of reps.
Very short sets (up to ~10 seconds) rely on the ATP/CP (aka alactic
anaerobic) mechanism.  Longer sets will rely most heavily on the lactic
anaerobic carbohydrate metabolism which can produce much more power than
the aerobic metabolisms.  This is why your muscles start to burn.  The
aerobic metabolisms will not significantly contribute unless each set
lasts several minutes.  I know of nobody who does or recommends
resistance training involving 10 minute+ sets.

Harry Phinney   harry@hp-pcd.cv.hp.com