Women vs. Men

By Wayne L. Westcott, Ph.D

My wife and I attended Vestal High School in upstate New York during the late 1960s. At that time we had some of the best high school athletic teams in New York State. There were no interscholastic athletic programs for girls, however. While I had some excellent sports experiences, my wife had no opportunities for athletic competition. It was simply assumed that high school girls did not have the physical or emotional capacity to participate in competitive sports.

Although girls were required to attend physical education classes, they had the impression that vigorous exercise and competitive sports participation were male activities. The boys did physical conditioning programs in preparation for sports competition, but the girls never had this experience. They were considered the weaker sex, and they had little opportunity to change this perception.

Today, we know that the most important physical activity for women in their 40s and above is sensible strength training. Progressive resistance exercise is clearly the best means for maintaining muscle mass and bone density during the midlife years, and is especially significant for post-menopausal women. 

Unfortunately, many women in this age range are convinced that they are indeed the weaker sex, that they do not have the physical ability to develop more strength, and that strength training may actually be detrimental to their musculoskeletal system. These assumptions are categorically untrue, and need to be corrected.

In fact, women are not the weaker sex. They have the physical ability to develop their strength, and strength training is highly-beneficial to their musculoskeletal system. Women need to recognize that they lose over 6 pounds of muscle tissue in every decade of adult life (Evans and Rosenberg 1991). Yet our research shows that women can replace over 3 pounds of muscle after only eight weeks of regular strength exercise (Westcott 1993). Because our muscle mass is closely related to our metabolic rate, maintaining muscular fitness helps maintain desirable body weight.

A few years ago we conducted a research study to compare the muscular strength of average adult males and average adult females (Westcott 1991). We collected data on more than 900 men and women, in one of the largest comparative studies of the sexes. The average age of the men was 43 years and the average age of the women was 42 years. The average body weight of the men was 191 pounds and the average body weight of the women was 143 pounds.

Each of the study participants performed 10 leg extensions with the heaviest weight load possible. This strength assessment for the front thigh (quadriceps) muscles was conducted on a Nautilus Leg Extension machine equipped with a special computer to ensure proper exercise technique with respect to movement speed as well as full movement range.

The results revealed that the male subjects were about 50 percent stronger than the female subjects. That is, the average 10-repetition leg extension for males was 119 pounds, whereas the average 10-repetition leg extension for females was 79 pounds.

This is not a fair comparison of muscle strength, however, because the males weighed almost 50 pounds more than the females on average. To better understand the strength abilities of men and women, we divided the weight they lifted by their body weight. When adjusted for weight differences, the average male completed 10 leg extensions with 62 percent of his body weight and the average female completed 10 leg extensions with 55 percent of her body weight.

While this body weight comparison certainly narrows the strength gap between the sexes, it is still not a completely accurate assessment. This is due to the fact that women have a higher percentage of fat than men.

To better examine pound-for-pound muscle strength between men and women, it is necessary to divide the weight lifted by the subjects’ lean (muscle) weight. When we made this calculation we found that the average male and the average female could both perform 10 leg extensions with about 75 percent of their lean weight.

Follow-up studies have demonstrated that women respond to strength exercise in the same rate as men (Westcott 1991). They are therefore not the weaker sex. They are the smaller sex, but on a muscle-for-muscle basis, women are just as strong as men.

Consider the results of a comparative study with an average adult male and an average adult female who followed similar strength training programs using the bench press exercise (Westcott 1995). As shown in Figure 1, both the male subject (who weighed 160 pounds) and the female subject (who weighed 95 pounds) increased their bench press strength by about 18 percent in a five-week training period. Once again, on a pound-for-pound basis with respect to both their body weight and their starting loads, there were no differences between the male and female responses to the strength exercise.

Another example of women’s strength response to a basic strength-training program involved six previously untrained females (Westcott 1985). The subjects in this study were assessed for muscle strength (10-repetition maximum weight load) in five Nautilus exercises (leg extension, leg curl, super pullover, biceps curl, triceps extension) at the beginning, midpoint, and end of the two-month training period. As illustrated in Figure 2, the women increased their overall muscle strength by 76 percent during the first month, and by another 13 percent during the second month. This resulted in a 100 percent improvement in overall muscle strength after the eight-week exercise session (from 140 pounds total workout weight to 280 pounds total workout weight). This is an incredible rate of strength gain, and clearly indicates that females can greatly improve their muscle performance. Although about 80 percent of the strength development may be associated with motor learning factors (better use of existing muscle tissue), the other 20 percent is related to physiological factors (addition of new muscle tissue).

That women can increase their muscle tissue is well documented in hundreds of female subjects who typically add 3 pounds of muscle after two months of basic strength training (Westcott 1995). In a study with 313 subjects, most of whom were women, the average muscle gain was 3 pounds and the average fat loss was 8 pounds, as a result of 20 minutes of strength exercise and 20 minutes of endurance exercise, practiced three days per week.

In, summary, male and female muscle tissue is essentially identical, and responds in a similar manner to strength training. Although females typically have less muscle than males, the muscle adapts to progressive resistance exercise in the same way. Most men and women respond to sensible strength training by developing stronger and slightly larger muscles. Considering that both sexes lose over 6 pounds of muscle per decade of adult life if they do not strength train, this is a very desirable effect of regular strength exercise.

I recommend that all women, especially those over age 40, perform regular strength exercise. Just be sure to check with our physician and consult with a certified fitness professional before beginning your strength-training program.

Wayne L. Westcott, Ph.D., is fitness and research director at the South Shore YMCA in Quincy, Massachusetts, and a strength training consultant to several professional organizations.  He is the author of the college textbook Strength Fitness, as well as several other fitness and exercise books.