Lisa Lindstein took up tennis at 16 so as not to be embarrassed in gym class the next term.

Lindstein, 36, took to the game smoothly enough to make her college's varsity team. This weekend, she enters the Montgomery County Adult Open as the No. 1 seed.

Lindstein learned to like tennis. She never became enamored with playing in tournaments. "When you play tournaments, sometimes you wait around waiting for the next player or if it rains and also, a lot of them take place the whole weekend and you waste the whole weekend waiting," said Lindstein, a patent examiner for the Patent Office. "I like to play more than I like sitting around. Hopefully when you play in a public park tournament, you get to play more."

Lindstein lost in the semifinals last year. Her sister-in-law Barbara won the tournament. Net Them Early

The U.S. Tennis Association is anxious to get American youngsters interested in the game as a primary sport. In various parts of the country, including the Washington area, the USTA is expanding its beginning programs for youngsters.

"Anytime you expand the base of kids, the better chance you have of getting more good players," said Brian Cunniff, director of the junior programs for the Mid-Atlantic Tennis Association, the local arm of the USTA. "We want to increase the base of tennis and expose as many kids as possible to the lifetime sport of tennis."

One avenue is the USTA School. Cunniff brings everything -- the program, the instruction, the T-shirts, the equipment -- to the 55 participating school districts in this region including numerous inner city schools, once an overlooked area by tennis associations.

On Monday, July 9, Cunniff is conducting a training session at the Washington Tennis Center at 16th and Kennedy Streets NW from 11 a.m. to 2 p.m. for USTA junior team tennis. It is a new program aimed at encouraging novice youngsters to play. Coaches from eight areas around the region -- Frederick, Baltimore, Montgomery County, Martinsburg, W. Va., Herndon, Alexandria, Virginia Beach and Prince George's County -- are invited to learn the program.

On July 21, from 10 p.m. to 7 a.m., there will be a Junior Tennis All Nighter at the Fairland Athletic Complex in Laurel. Unranked younger players will get to play organized tennis, with local pros giving free instruction.

Among the fun will be a disc jockey playing music, a video camera to analyze the individual form of players and a radar gun to measure the speed of serves. For more information, call 321-9045. Serve-and-Volley

Randy Vigmostad, the Mid-Atlantic men's outdoor champion, is hoping that title and other winning exploits put him in consideration for a qualifying spot in the Sovran Bank tournament at the end of the month.

Vigmostad used to play in tournaments like the Sovran for a living. He quit the professional tour four years ago. He said he ranked in the 200's in doubles and 500's in singles.

"I left because of what you needed to do to play; it's the game I love," he said. "The competition -- that's why I still go out and play." . . .

Growing interest in tennis in Washington has led to formation of the D.C. Recreation and Parks Tennis Club. For those ready for competition, the D.C. Open will be at the Takoma Recreational Center, July 21. For information about the club or the tournament, call D.C. tennis coordinator Mike Ragland at 767-7345.