Traditionally, women have been reluctant to engage in resistive exercise, for several reasons. First, many women fear the possibility of gaining significant amounts of bodyweight, and/or taking on male characteristics. This fear is reinforced when women see their peers in strength and power sports such as weightlifting, bodybuilding, and the throwing events in track & field.
An additional factor to consider is that women, by virtue of their high proportion of slow-twitch muscle fibers and low levels of the male hormone testosterone, are not inherently talented when it comes to strength performance. If you look around the next time you're in the gym, you'll see that most men concentrate on strength training, while most women focus on aerobic fitness and flexibility - people tend to do what comes easiest to them, and avoid the fitness components that really need the work.
Nevertheless, while men and women have more similarities than differences, there are several key things to keep in mind if you're a woman looking to improve your strength preparation, or if you train women as a coach or trainer:
1) Women often have hypermobile (overly loose) elbows and knees, as compared to men. Women who can hyperextend either their knees or elbows beyond 180° should pay extra attention to the hamstrings and arm biceps (using leg curls and arm curls, respectively) in their weight training program. Shortening these muscles will improve the stability and reduce the potential for injury at the elbow and knee.
2) Women have wider hips than men in general, which often potentiates tracking problems of the kneecap. In such cases, paying extra attention to the vastus medialis muscle (the "inner" part of the quadriceps which helps to offset the usually stronger vastus lateralis) can go a long way toward alleviating knee pain and dysfunction. One way to accomplish this is through the use of leg extensions, performed only at the last 10 to 20 degrees of extension. Well-designed equipment, such as machines provide built-in range of motion limiters for this purpose.
3) Although few women can gain appreciable muscle mass through weight training, it may surprise many to know that high reps may have the greatest potential to put muscle on the female body. This is because slow twitch muscle (which most women have plenty of) responds best to endurance activities. If you've ever wondered why that rowers and kayakers have large back muscles despite large volumes of distance training, now you know the reason. Athletes of either gender who wish to get stronger without getting bigger are best served by low (2-3) repetition sets. A word of caution, however: this type of training should only be considered after a significant (1-2 years) period of work performed in the 6-12 range.
4) Women who wear high heels are prone to excessively short calf muscles and tendons. Wearing heels prevents these structures from reaching their normal length, which in turn causes a compensatory shortening. If at all possible, bring a pair of low-heel shoes with you, so that you can switch back and forth during the day. In any event calf stretching should be a high priority if you wear heels.
5) Eating disorders (and poor eating habits in general) appear to be at an all-time high among women in the U.S.A. If you are not eating enough calories (and particularly, the right kind of calories), you simply will not have an adequate support mechanism for proper training. In my experience, women tend to eat too infrequently (I suggest 5-6 meals per day), and when they do eat, too many calories come from carbohydrates, and too little from fat and protein. On the other hand, women tend to do a better job with drinking enough water than their male counterparts.
6) Women tend to enjoy (and in my opinion, over-do) aerobic exercise, due to their high proportion of slow twitch muscle. If you fit into this category, try to keep aerobic sessions as far away from strength sessions as possible- preferably on opposite days. If you feel you must do both during the same session, perform the strength component first.
7) Women tend to have better flexibility than men, and spend a lot more time stretching than men. Unless you have a specific flexibility deficit, you're better off stretching after strength training sessions, rather than before them. This is because most forms of stretching leave the muscle temporarily weaker, which will compromise your efforts in the weight room.
8) Due to factors listed in point #6, women often tend to make strength sessions more like cardio sessions, by emphasizing high reps, and utilizing short (and often, incomplete) rests between sets. Remember that muscles get stronger by being exposed to high tensions, not by undergoing long workouts.
Finally, it's interesting to observe that, as women's sports become more popular, the performance differences between men and women have been narrowing. This may indicate that women are not as physiologically "inferior" from men as many have assumed, but instead, social and cultural factors are more to blame. With the recent popularity of women's professional boxing, basketball, and other sports, women are enjoying enhanced opportunities in sport. Hopefully, this will lead to greater scientific research and technological advances in female athletic performance.