When the 1972 Olympics were held in Munich, there were maybe 15,000 men and women gymnasts practicing in private clubs throughout the United States. Today that number has grown to more than 150,000, and at the upper level, US talent has reached the point where it ranks among the top five gymnastic countries in the world.
''We're good and we're getting better,'' said Bill Meade, head gymnastics coach at Southern Illinois University for the past 28 years and an assistant US Olympic coach in 1968. ''Both our men's and women's teams are capable of competing with anyone. They're aggressive; they know what they have to do; and they are willing to put the time in to get it done.
''While the Soviet Union still rates ahead of us and probably will be favored to win most of the gymnastic events at the '84 Games, we're continually working on more difficult and more spectacular routines,'' Meade continued. ''We also have to be concerned with the Japanese, who are always very strong in gymnastics.
''But by next July, the way we're going, we may have caught or even passed the Japanese. After that I'd rate China as the fourth-best in the world, followed by the German Democratic Republic.''
Although 13 countries were entered in last week's McDonald's 1983 International Gymnastics Championships at UCLA's Pauley Provision, much of the luster disappeared when both the Russians and the Chinese declined invitations. In their absence, the meet became more of an exhibition - a showcase for US flair and talent.
Asked to describe gymnastics, Meade replied: ''Well, it's a sport where you challenge your body to do things that it has never been asked to do before. You need a lot of stamina; the reactions of a boxer; and a kind of fearlessness inside yourself that says everything is going to come out all right. Probably the ideal size for a male gymnast is 5 ft. 8 ins. and 140 lbs.
''Girls, because they are lighter and seldom as tall, don't need as much strength to move their bodies around,'' he added. ''They often start gymnastics as early as five or six years old. The problem is that 10 years later a lot of those kids are burned out. And I think this is easy to understand, once you realize that most girls who are serious about gymnastics practice between five and six hours a day, seven days a week.''
One female who explodes the burn-out theory is Kathy Johnson, a seven-year member of the US team who is still among the top contenders for an Olympic berth and is currently ranked fifth in overall competition. Kathy, who is strongest in the floor exercise, won a bronze medal in the 1978 world championships, making her and Marcia Frederick at the time the only two US women since Kathy Rigby to win medals in worldwide competition.
Other contenders for the women's team year include Diane Durham, currently ranked No. 1, Mary Lou Retton, Julianne McNamara, and Tracee Talavera.
Meade says boys tend to get into the sport much later than girls, like at 12 or 13.
''But they invariably last longer than the girls, who undergo greater body changes growing up,'' he noted. ''For example, a woman's center of gravity changes as she gets older, making it far more difficult for her to maintain her skills.''
Mitch Gaylord, a junior at UCLA, is the nation's No. 1 ranked male gymnast on the strength of his victory in the US Championships in June. Among his leading rivals are Peter Vidmar, Jim Hartung, Phil Cahoy, and Bart Conner.
''Gymnastics is a very demanding sport both on the body and the mind,'' Meade said, noting the constant pounding of the knees and shoulders plus the mental strain that comes with all that intense concentration. Then too, he pointed out, there's the aspect of not letting anything in their private lives interfere with their careers as gymnasts.
''After a while, kids aren't willing to do that anymore,'' he said. ''Suddenly they want all the normal things, like cars, jobs, vacations, and dating.''