In the old days, we believed that it was inappropriate for women to have
muscles. We also thought that if they did the same exercises as men, they
would begin to look like men. So they were naturally afraid to do any type
of training exercise.
Women can build but it is not as easy to pack on the muscle. So they don't
usually develop the same size muscles. There are exceptions, but it takes
years for anyone to look like Swartzenegger and some will never, no matter
how much they train. Pushups, traditionally done on the knees by women,
do practically nothing to strengthen the muscle structure. It is rare for
anyone to actually bulk up using body weight alone. Additional weights
would be required.
The muscles that are targeted in pushups are the triceps, pectorals,
shoulders and back muscles. Pectorals are important for a number of reasons.
They provide protection for the thoracic cavity due to impact (seat belt
in a car accident, etc). They provide support for the chest for both men
and women to avoid sagging. They also assist in breathing to lift and
expand the thoracic cavity.
In fitness classes, women are genuinely surprised when requested to do full
pushups. The visual results are very little building, some good toning,
increased definition and greater strength. The added benefit of denser muscle
is that it is smaller and heavier unlike training with external weights which
build larger denser muscles. Actually the reduction in size comes from an
increase in the metabolic rate which burns fat. The metabolic rate increases
by 50 calories per day for each pound of lean muscle added. So flabby muscles
get pulled in tighter and denser and fat burns away. So, this is a good reason
to not use a bathroom scale. It can be very misleading. Many people have cancelled
workout programs thinking they were useless because their scale indicated that
they were heavier than before they started training. To put it in perspective.
Go to the supermarket and compare a 2 pound lean steak with a 2 pound tub of
fat/lard. There's a big difference in volume.
Some people build faster than others, but we all level off well below what
would occur if we were actually pumping iron. So, don't be afraid of the burn,
and besides, it's only lactic acid buildup in the muscles.