Behind a tall chain link fence, hidden by thick rows of shrubbery and ruffled tarpaulin drapes, tons of prime college football muscle auditioned this week for a shot at the National Football League.

More than 150 college seniors were flown in from campuses across the nation and tested for speed, strength and agility. Marcus Allen, the Heisman trophy winner from Southern California, Ohio State quarterback Art Schlichter, Texas tackle Kenneth Sims, and a host of lesser-known talents performed under the watchful guidance of 16 NFL team representatives.

They came here at the request of the United Scouting Combine, a scouting group funded by the 16 teams. Information gathered on the prospects by the scouts is pooled in preparation for the April draft.

The Buccaneers have played host the past two years, offering balmy weather for the tryout and a training field obscured almost completely from public view. One can catch only a glimpse of the top-secret activities from the balcony of a nearby motel.

From that vantage point, a three-ring circus of long jumping, 40-yard sprints, vertical leaping and assorted endurance exams could be seen. The seniors wore gray shorts and white jerseys, with their names and numbers printed in red letters on the back.

Cincinnati Coach Forrest Gregg jotted notes on a clipboard. Marv Levy of the Kansas City Chiefs squeezed a stopwatch as a pack of lineman barreled past him.

Not far from the pack, Washington General Manager Bobby Beathard and Coach Joe Gibbs watched the bodies move in the warm Tampa breeze and compared notes. Since the Redskins don't have a first-round draft pick this year, barring a trade, both men have spent the week observing the candidates casually and looking at players who might be available in lower rounds.

"Personally, I'm against this kind of thing," said Beathard. "It's like socialized scouting. I don't like it at all, because I think each team should do its own work. I spoke up against it at the league meetings, but it didn't make any difference."

Beathard conceded the combine's tryout has certain benefits. "If nothing else, it gives you a chance to see all the players together," he said. "You might like two players, but if you can see them perform side by side, that might give you a better idea of which one you want."

Through much of the tryout, Beathard and Gibbs scrutinized defensive linemen.

"That's probably our top priority," said Gibbs. "If you had to list our basic needs in order of importance, I'd say it's finding a defensive lineman, a cornerback and then a good, fast receiver. But if we can't get what we want, we'll settle for the best overall athlete available."

Without a No. 1 draft pick, Gibbs has had to keep his thoughts from wandering to the blue-chip talent floating through camp. But if he did have one top pick, Gibbs knows how he'd use it.

"Sims," he said. "We want to have that pass rush."

The New England Patriots are expected to take Sims, winner of the Outland Trophy as the best college lineman. Naturally, their representatives were in attendance this week, along with those from Washington, Tampa Bay, Atlanta, Cincinnati, Cleveland, Denver, Green Bay, Houston, Kansas City, Los Angeles, the New York Giants, the New York Jets, St. Louis, San Diego and New Orleans.

United is the largest of the NFL combines. BLESTO consists of seven clubs, and the Dallas group, which is dominated by the Cowboys, has five teams. Until this year, the league allowed combines only to conduct physical examinations. Players had to be tested and worked out at their respective colleges. But the league decided this year that it would be more economical to stage the tryout procedure at one site.

How do the players feel about it?

"It can make your chances for the draft better or worse," said defensive back Sammy Sims of Nebraska. "It's kind of scary, but they tell us not to worry about it."

Jim McMahon, the all-America quarterback from Brigham Young, expressed confidence in his chances. "I don't think there's any doubt in their (the scouts') minds that I can play," he said.

But everyone isn't like McMahon, who should go high in the draft. The combine also gives more obscure players a chance to shine. Robert Abraham, inside linebacker from North Carolina State, is one such player.

"It's great," he said, "because I wasn't asked to play in any of the postseason bowl games."

All sessions have been closed to the press and public, supposedly to protect the players, according to one combine official. The private workouts also keep rival combines from sneaking a peek.

"If nothing else," said Gibbs, "this gives me a chance to see players I might not have gotten a good enough look at. And that can always come in handy."