Is nothing sacred? Women have now invaded one of the few remaining male athletic bastions - weightlifing.

Last April in Nashua, N.H., the Amateur Athletic Union sanctioned the first official women's powerlifting competition. Iowa's Terry Dillard set a record in the 114-pound class by deadlifting 314 pounds. The lightest woman, a mere 105 pounds, deadlifted 300 pounds.

These contestants weren't humanoids created in some bizarre scientific experiments; rather, for the most part, they were women who got into the sport originally to improve a weak tennis backhand or to tone up their bodies. And they don't look like Magilla Gorilla's girlfriend.

"The girls who compete in the lighter classes are gorgeous," says Mark Cameron, a weight-training instructor at the University of Maryland. "They have nice figures and look like models."

It is testosterone, a male hormone, that allows men to develop bulging muscles. Since women, as a rule, have very little of it, they can greatly increase their strength without enlarging the muscle mass.

Since there's a ceililing on the strength women can attain, according to Barbara Miller of the Office Health Club, because of a direct correlation between the size and strength of muscles, a woman powerlifter will never lift as much as her male counter-part in competition; but there's still a lot of potential.

Joe Zarella, national chairman of AAU powerlifting competition, has championed women's competition. "I was meeting women who were being shunned by the committee." He explained. "The AAU is male-dominated and the women were forced to compete under men's rules and conditions." So in the spring of last year Zarella ran a meet to prove that it was a viable and exciting sport for women, too. This past April Zarella presided over the first AAU-sanctioned women's competition, with 74 contestants from around the world. Several world records were set in the seven weight classes.

While gearing up for October's "Iron Lady Open" in Indiana, he's also pushing for international recognition by the Olympic, committee; until then all records are unofficial.

Locally there seem to be no competitive women weightlifters (using overhead lifts) or powerlifters (dead lifts: bending over with legs apart, grasping the barbell with overhand grip and slowly straightening the back with the arms extended down; bench press: lying on a bench and lifting the barbell up from the bench bracket rest; and squats or deep knee bends with barbells positioned behind the neck). There are a lot of women who train with weights as a supplements to other ocmpetitive sports.

Susan Liebenow, women's tennis coach at Georgetown University, recommends workout for specific problems - like improving a tennis wrist grip or strengthening an ankle. Billy Jean King brought herself back to a competitive level in tennis by following a strengthening program of weight training.

Pat Sullivan, women's volleyball coach at George Washington University, finds weight training essential for the jumping, spiking, dodging and rolling that go with the sport.

Recent studies of college physical education departments revealed that female athletes suffer far more injuries than their male counterparts because of poor (if any) pre-college conditioning.

As for the rest of us, we who have been attempting or contemplating getting back into shape (or just into shape), there is hope. Mark Cameron insists that weight training can be adapted to any level, regardless of the aspirant's condition. "You're never too old," he insists. The first is to get a checkup from your doctor. If you have a bad back or congenital weakness, or are recovering from an illness or operation, you shouldn't try any physical exercise program without supervision.

Doctors report that many back injuries and strains are caused by lifting heavy objects and could have been avoided if the victims had adequate back and shoulder strength. Barbara Miller says that nearly all men and women have extremely weak abdominal muscles, which means a weak lower back, and that these have to be strengthened before taking on any weight-training program. She advises consulting an instructor to learn to do essential exercises correctly. I did, and found I was doing my sit-ups too quickly and with the wrong muscles.

For anyone with motivation problems (and Miller says that's the case with many of the women she counsels), the easiest way to work out is to join a health club or try to sign up training class at a university. Maryland, American and Howard all offer such courses. Some health clubs offer trial memberships with no obligation to commit yourself to a long-term contract. Be wary of any outfit that pushes extended memberships harder than proper exercise.

Tyrone Lewis, a weight-training instructor at Howard, says that more women sign up for his classes each semester - mainly "just regular students who want to develop strength and condition themselves."

Lewis, Cameron and American University instructor Bill Coward say they try to acquaint students with basic skills and fundamental techniques as they can develop their own fitness programs. Football demands different weight-training exercises from those needed for basketball or tennis. There are also necessary precautions to avoid injuries - it's easy to pull a muscle.

If your budget makes joining a club or class impossible, an informative and encouraging book by Kathryn Lance called "Getting Strong" (1978, Bobbs-Merrill, 226 pages) covers studies on women's fitness, the purpose of developing upper-body strength, a crash introduction to the world of weight training and a do-it-at-home program the author refers to as "pumping tomato juice."

Lance believes that since most women who start a weight-training program will initially use weights of five pounds and less, they can easily adapt water-filled plastic bottles, irons or anything else around the house that's relatively easy to grasp. While commercially made weights have better grips and balance, Lance feels that people should "see what it's like and then buy equipment if they want to go futher."

Lance is an evangelist of physical fitness. Five years ago, at the age of 29, she was an overweight chain-smoker with extremely high blood pressure. Faced with taking medication for the rest of her life, she started jogging and was born again. She slimmed down and believes it calmed her nerves enough to stop smoking and lower her blood pressure to a normal range.

"As a runner I believed I couldn't get any more fit, until one day I tried to pick up a full suitcase and nearly ripped my arm off." Without upper-body strength, she realized, she couldn't lift her typewriter or portable sewing machine, or open a jar of olives. Worse, her boyfriend regularly beat her at handball by serving to her weak backhand.

After a year of research and weight training, "I have reworked my body with weights. My figure is much better, bust is bigger, waist smaller and my underarms are much firmer."

And best of all, she no longer loses at handball. Her backhand is so powerful.