Beside gymnastics talent, Margie Foster has a lot of other things going for her in her quest to make the 1978 Olympic team - a former professional baseball pitcher turned personal coach, her personal music arranger and a computer-mathematics teacher who sometimes doubles as her personal hairdresser.

They are, respectively, her father, brother and mother, and the story of the Foster Family is one that reflects the sacrifice, tenacity and hard work that American amateur athletes must have to even dream about Olympic participation.

"My wife and I teach. We're very fortunate to have two good jobs. There are other People less fortunate and their daughters drop out so the family won't suffer (financially)," said Tom Foster, a Gloversville, N.Y., elementary school physical education teacher who estimates that travel costs to gymnastics meets run about $3,000 annually.

Foster once played in the St. Louis Cardinal farm system before entering teaching. He talks hopefully of pending government legislation that would help provide training opportunities for potential Olympians and provide more competitive events for them such as this week's meet at George Mason University.

Foster, 17, placed first in the all around category in a regional qualifying meet for the MarVaTeen-sponsored Junior Olympic Eastern championships that began yesterday and continue today in 2 p.m. and 7:30 p.m. competitions. The finals are tomorrow at 7:30 p.m.

When she was 11, Foster said her mother, MaryAnne, enrolled her in a dance school that also offered acrobatic lessions and gymnastics.

"My father didn't know that much about gymnastics then and I didn't, so we started working together on strength exercises," she said.

Together they attended gymnastics clinics and pored through gymnastics books. Tom Foster built an exercise bar in the basement and eventually became so involved in the sport that he and two friends founded the F-M Flairs Gymnastics team.

Foster's five sisters also are involved in gymnastics and her brother, Tom Jr., a student at the Crane School of Music, handles the music arrangements for her free-exercise routines.

Her day begins at 5:45 a.m. with a three-mile jog before she goes off to Gloversville High, where she is an honors student. She has combined her junior and senior years so she will graduate in June. Recruited by six colleges, she will attend Penn State on a gymnastics scholarship.

After school two days a week, she works out at a nearby junior college from 6 until 9 p.m. On the other days, she and the other 28 team members work out at her father's school, where the equipment is more limited.

"This isn't like a regular gymnastics class where you just walk in and everything's set up for you. We work at the oddest of hours," said her father. "We have to set up and break down the equipment every night. By the time we get home, it's often 10 o'clock."

Foster, 5-foot-1 and 108 pounds then does three hours of homework. "Sometimes she'll go to 1 or 2 in the morning just to finish her work," said her father.