|
APPENDIX A
PHYSIOLOGICAL DIFFERENCES BETWEEN THE SEXES
Soldiers vary in their physical makeup. Each body reacts differently to varying
degrees of physical stress, and no two bodies react exactly the same way to the
same physical stress. For everyone to get the maximum benefit from training,
leaders must be aware of these differences and plan the training to provide
maximum benefit for everyone. They must also be aware of the physiological
differences between men and women. While leaders must require equal efforts of
men and women during the training period, they must also realize that women have
physiological limitations which generally preclude equal performance. The
following paragraphs describe the most important physical and physiological
differences between men and women.
SIZE
The average 18- year-old man is 70.2 inches tall and weighs 144.8 pounds,
whereas the average woman of the same age is 64.4 inches tall and weighs 126.6
pounds. This difference in size affects the absolute amount of physical work
that can be performed by men and women.
MUSCLES
Men have 50 percent greater total muscle mass, based on weight, than do women. A
woman who is the same size as her male counterpart is generally only 80 percent
as strong. Therefore, men usually have an advantage in strength, speed, and
power over women.
FAT
Women carry about 10 percentage points more body fat than do men of the same
age. Men accumulate fat primarily in the back, chest, and abdomen; women gain
fat in the buttocks, arms, and thighs. Also, because the center of gravity is
lower in women than in men, women must overcome more resistance in activities
that require movement of the lower body.
BONES
Women have less bone mass than men, but their pelvic structure is wider. This
difference gives men an advantage in running efficiency.
HEART SIZE AND RATE
The average woman’s heart is 25 percent smaller than the average man’s. Thus,
the man’s heart can pump more blood with each beat. The larger heart size
contributes to the slower resting heart rate (five to eight beats a minute
slower) in males. This lower rate is evident both at rest and at any given level
of submaximal exercise. Thus, for any given work rate, the faster heart rate
means that most women will become fatigued sooner than men.
FLEXIBILITY
Women generally are more flexible than men.
LUNGS
The lung capacity of men is 25 to 30 percent greater than that of women. This
gives men still another advantage in the processing of oxygen and in doing
aerobic work such as running.
RESPONSE TO HEAT
A woman’s response to heat stress differs somewhat from a man’s. Women sweat
less, lose less heat through evaporation, and reach higher body temperatures
before sweating starts. Nevertheless, women can adapt to heat stress as well as
men. Regardless of gender, soldiers with a higher level of physical fitness
generally better tolerate, and adapt more readily to, heat stress than do less
fit soldiers.
OTHER FACTORS
Knowing the physiological differences between men and women is just the first
step in planning physical training for a unit. Leaders need to understand other
factors too. Women can exercise during menstruation; it is, in fact, encouraged.
However, any unusual discomfort, cramps, or pains while menstruating should be
medically evaluated. Pregnant soldiers cannot be required to exercise without a
doctor’s approval. Generally, pregnant women may exercise until they are close
to childbirth if they follow their doctors’ instructions. The Army agrees with
the position of the American College of obstetricians and Gynecologists
regarding exercise and pregnancy. This guidance is available from medical
authorities and the U.S. Army Physical Fitness School (USAPFS). The safety and
health of the mother and fetus are primary concerns when dealing with exercise
programs.
Vigorous activity does not harm women’s reproductive organs or cause menstrual
problems. Also, physical fitness training need not damage the breasts. Properly
fitted and adjusted bras, however, should be worn to avoid potential injury to
unsupported breast tissue that may result from prolonged jarring during
exercise. Although female soldiers must sometimes be treated differently from
males, women can reach high levels of physical performance. Leaders must use
common sense to help both male and female soldiers achieve acceptable levels of
fitness. For example, ability-group running alleviates gender-based differences
between men and women. Unit runs, however, do not. |
|
