Just when you thought you had recovered from the amateur athletic blitz of 1984, along comes the National Sports Festival for a return engagement.

On a slightly different scale, with slightly different purpose, the National Sports Festival, which will open Wednesday in Baton Rouge, La., offers almost everything the Olympics do.

The 12 days of competition (ending Aug. 4) will bring together American athletes in 34 sports in competition that was originally designed by the U.S. Olympic Committee as a vehicle to develop future Olympians. It can only be called a success.

The opening ceremonies for the first festival, in 1978, drew about 3,000 people to Memorial Park in Colorado Springs. Wednesday,, about 76,000 are expected to fill Louisiana State University's Tiger Stadium for the opening festivities. The university and the city of Baton Rouge are acting as co-hosts.

Besides the growth in interest, especially among cities wishing to host the games because of the financial and publicity benefits, the festivals have increased the participation in amateur athletics and helped inspire some athletes to greater performances.

At the 1981 festival in Syracuse, N.Y., a girl from Fairmont, W.Va., who got relatively little attention at the time, won three gold medals in gymnastics. You can now find Mary Lou Retton in fast-food commercials and on Wheaties boxes everywhere.

Some of the gold medal winners in Los Angeles will be competing in this year's festival.

Roger Kingdom, who surprised many people by beating Greg Foster to win the Olympic 110-meter hurdles, is scheduled to race on the new all-weather track at Mumford Stadium on the campus of Southern University.

Al Joyner and Mike Conley, the gold and silver medal winners, respectively, in the Los Angeles triple jump, are scheduled to appear, as is three-time gold medal-winner Valerie Brisco-Hooks.

Willie Banks, who last month set a world record in the triple jump (58-11 1/2) at The Athletics Congress meet in Indianapolis, also is scheduled to compete.

A number of Washington-area athletes will be competing in the festival. Georgetown junior Raymond Humphrey, who this year won both the long jump and the triple jump in both the indoor and outdoor IC4A championship meets, will compete in the already-packed triple jump field.

Four boxers -- James Harris, Lyndon Walker, Darryl Lattimore and Alton Rice -- will represent the District. Olympic canoeist Bruce Merritt of Ridge, Md., will compete, as will kayakers Linda Fraile of Bethesda and Kathy Sisk of Washington, to name a few. A handful of area players are on the soccer teams, including Richard and Robert Ryerson of Laurel.

Another local athlete is a festival veteran.

Chuck Michaels, 26, of Arlington and the University of Texas, has been at every festival since 1978. The first three times, he competed in the modern pentathlon, but then added fencing to his list of activities in 1982 and 1983. He has won seven festival medals, including the gold in individual epee in 1983. Michaels, who was sixth in last summer's U.S. Olympic trials, will be leaving for the World University Games in Kobe, Japan, shortly after the festival.

"In some sports, the National Sports Festival is more important than in others," Michaels said. "Some sports use it to select teams, but in modern pentathlon it's basically training. But the best part is that it is a time for all the athletes to get together. The world championships in each sport always are scattered all over the world. I'm not able to meet the people in track or swimming or weightlifting or whatever. I have my idols in other sports and I like to see them.

"The competition is very high-powered. There's usually the top 100 fencers trying to make the world championship team, but in the sports festival, there are only 20. You have to be on your toes because you know that even your first bout is against one of the top 20." One of the changes in this year's festival will involve drug testing.

The USOC recently announced a beefed-up drug-control program and said that positive tests for banned substances will result in punitive actions by the national governing bodies of the sports involved, or by the USOC.

The first stage of the new program will involve testing of medal winners and random tests administered to athletes at the 1985 festival. There will be 350 to 400 athletes tested in Baton Rouge, using mobile labs and other facilites, with the IOC-certified laboratory at UCLA as the control point for the results.

"The new program should go a long way in convincing our athletes and coaches that the use of banned substances is a thing of the past," USOC Secretary General George D. Miller said in a statement.

"We have had more than a year of education for our athletes on the use of these drugs, and the time has come that tests proving positive will result in penalties. We want to make sure our athletes stay drug-free in training, as well as at the Olympic Games, and this program, which is being carried out with the cooperation of each of the national governing bodies first, will make that possible."