It was hot fun in the summertime yesterday at RFK Stadium as more than 30,000 people gathered to shake their bodies to the music of some of the top soul and funk bands in the country.

Yesterday's daylong concert, the "D.C. Throwdown," was blessed with clear skies and easy breezes. For many it was the biggest event of the summer and for some the biggest concert of their lives.

"This is one of the biggest concerts in my life because Ray Parker is here. I'm trying to figure out a way to get back there and get his autograph," said Jacqueline Magee, 26, who said she drove down with friends, leaving Wilmington, Del., early yesterday morning.

Yet some approached the gates of the stadium with apprehension. In 1974 and 1975, Human Kindness Day rock concerts drew thousands, but were marred by violence that eventually prompted cancellation of the events.

Kim Edmunds, 16, of Suitland, was one of the worried ones early yesterday afternoon. "You know there's going to be some fights. Guys are going to be saying, 'He stepped on my foot,' 'Hey, what are you doing talking to my girl?' and then there's going to be some fists flying."

By late in the afternoon, three of the seven scheduled groups had entertained the dancing and cheering crowd. Early this morning, police reported a total of 39 arrests, mostly for drug-law and vending violations, but said none of the incidents was major.

About 20 people were treated and released at D.C. General Hospital for injuries ranging from minor cuts and bruises to broken bones, a hospital spokesman said last night.

Most of the injuries occurred when people were shoved and trampled by crowds, said Dr. Donald Thomas, director of D.C. General's emergency room.

He said one woman suffered a broken toe, a man's elbow was broken and a 12-year-old girl suffered a broken wrist when they were pushed around by people running from fireworks that someone set off in the crowded field.

Long before the first band, One Way, was scheduled to perform at 3 p.m., Metro trains swelled with concertgoers sped toward the stadium. Inside, the passengers were loaded down with vacuum bottles, blankets, coolers and anticipation.

Outside the stadium, vendors stood waiting. Carl Hylton was taking pictures of concertgoers and selling them, and Lisa Williams, 15, of Benning Road NE couldn't resist. She was ready to preserve this day for a mere $3.75. Decked out in a preppy yellow knit top and white shorts, socks and sneakers, she crossed her legs and leaned to the side as she sat down in the wicker chair.

"These types of kids at this age are really concerned about how they look and dress. It's all part of going to a concert like this," Hilton said. "They like to look back at these pictures and say 'Look how bad we were.' "

Inside the stadium, a carpet of bobbing heads was spread out over the field, with the stage at the south end, separated from the crowd by a seven-foot wooden wall and a row of security guards perched on the inside of the wall.

From this raised platform, framed with massive speakers, the performers held forth: War, with its percussion-heavy California sound of conga drums, guitars and electric piano; Parker, crooning songs like "The Other Woman" and "A Woman Needs Love"; One Way's funky version of "Cutie Pie" and the Prince of Punk Funk, Rick James, his shoulder-length, braided hair spraying in the air as he wheeled about the stage.

Along with them were Cameo, a New York-style funk group; an electric funk group with synthesized vocals, Zapp, featuring Roger, and Washington's own Experience Unlimited.

During One Way's performance of "Fancy Dancer," Ruth Cardwell, 39, from Southeast Washington stampeded to an open spot on the field and planted her feet and shook her bones in the summer sun. "I love it," she shouted.

A few yards away, Jimmy Jones, 33, of Northeast Washington stood in a black cloak and hood barely nodding to the music from behind his honey-colored sunglasses. He said he was just enjoying watching the people and watching the people watch him.

"I feel like Jesus Christ," he said responding to people's questions about his garb. "Actually, "I'm burning up in these clothes. I just dress like this so that I'll be recognized."

High above the mass of churning humanity, the stadium's general manager, Robert G. Sigholtz, listened to the rambunctious sounds of guitars, drums and vocal chords and remembered similar concerts in earlier years that had been marred by violence.

"But we don't expect anything like that today," Sigholtz said, smiling. "There was more unrest in our society at that time. It was too close to the disturbances we had here in 1968. To say that these youngsters won't behave is ridiculous."

Sigholtz said that there were 200 unarmed courtesy patrol workers, 25 guards, 30 U.S. park policemen and about 125 D.C. police officers and officials on hand to manage the crowd.

"We believe in crowd management, not crowd control. Everybody's here to have a good time and we want to make sure that a few people don't spoil the fun for everyone else," he said.

Back down on the field, Clark Brown, 19, was dancing bare topped, his legs pumping back and forth in fatigue pants as he danced the electric boogie. "D.C. is the happening. There is nothing like D.C.--Chocolate City," he said. "Everybody's together; we're one."