EIGHT-YEAR-OLD Mia Sprenke is about to enter the big leagues. For the past few years, Mia has confined her racing efforts to the one-mile fun run around Stanton Park. But this Sunday, Mia will team with her father and older brothers in the 10K Capitol Hill Classic, one of several area races where the whole family can be in the running.

"My mom told me if I trained a lot I could run the 10K this year," says Mia, a third-grader at Peabody Elementary School, whose PTA sponsors the race to finance equipment and enrichment programs for Peabody and for the Hobson Middle School on Capitol Hill. (Besides the main race, which parent-child teams are encouraged to enter, there are fun runs for children under 12 and even a mini-race for toddlers.)

"Sometimes I run around Stanton Park, and yesterday I ran to the Capitol," she says. "And on vacation I went to my aunt's house in San Antonio and I ran the 5K."

Many serious area runners regularly participate in the Capitol Hill Classic, athletes like David White, Tem Washington, Barbara Frech, Becky Nolan and J.J. Wind. But it also draws many neighborhood residents who otherwise don't run races.

"It's fun to run the neighborhood," says Tom Getman, whose wife Karen and children Andrew, 16, Eliza, 14, and Tim, 10, will run this year's 10K as a team.

Two years ago, Tom and Andrew placed second in the family competition (in which a team's time is the average of its two fastest runners' times), and "that was because of his speed and my stamina," says Tom.

Andrew has finished the Marine Corps Marathon in three hours and twenty minutes and runs cross country for St. Anselm's Abbey School -- but for the rest of the family, speed isn't everything.

"It's the camaraderie that keeps us going," says Karen Getman. "Friends and neighbors line the route to encourage, to tell you you can do it."

"One year somebody pushed me up Capitol Hill," adds Eliza.

The run up the hill on Constitution Avenue is considered the toughest part of the race, which starts at Stanton Park, follows Massachusetts Avenue to Lincoln Park, loops around RFK Stadium and returns along East Capitol Street. The runners then barrel down the House side of Capitol Hill, along Independence Avenue, skirt the western Capitol grounds and climb Constitution back to Stanton Park.

"It's a great course because you're running through your own neighborhood and friends are out there yelling for you," says Mary Donovan, captain of one of the few mother-son teams running the race this year. Donovan will run with her two sons, Derek Mattioli, 7, and Roger Mattioli, 11.

"Derek's never run the 10K before, but if he can't finish, he can walk home from anywhere on the course," says Donovan. "Roger will finish, even though he'll complain that his legs are killing him. It's a great source of pride for kids who live on the Hill and go to these schools to say they ran the 10K . . . .

"I'm not a fast runner, and when I run the Capitol Hill Classic I know I'm not going to place. I just think about how much fun it is -- until I get to Capitol Hill and have to run up the darn thing. Then I remember that my husband is still in bed." CAPITOL HILL CLASSIC -- Registration is from 10 to 4 Saturday at Peabody Elementary, 5th and C NE. Fees are $10 for the 10K, $5 for the fun runs; T-shirts to all participants ($7.50 otherwise). Last year's winning times were 31:12 for men, 38:06 for women. The top five male and female finishers will receive trophies, as will the top three runners in each of seven age groups and the top three team and group winners. All participants in the fun run will get ice cream and a balloon, courtesy of Capitol Hill merchants. The race begins Sunday at 8:30 a.m.. FAMILY FOOTWORK

Here are some other coming races with opportunities for families and children to participate:

10K RACE -- to benefit Children's Hospital, with medals to the top finishers in several age categories, including 12 and under and 13 to 15. Register at Herbert Hoover Jr. High School in Potomac before the race, which starts at 8 a.m. Saturday. Call 299-5751.

NAVY RELIEF SOCIETY RELAYS -- at Quantico Marine Base, with four legs totalling 12.2 miles. Awards to winners in several different age groups, including children. Register Saturday before 8 a.m. at the Naval Medical Clinic at Quantico. Call 703/640-2201

5K RUN -- Saturday at 9 a.m. through Anacostia Naval Air Station. Kicks off festivities for Family Day, which is Sunday at the Washington Navy Yard. Call 433-2016.

LAKE RIDGE MAY DAY 10K -- starts at 8:30 a.m. Sunday from the Ridge-Wood Community Center, Lake Ridge, Va. There is also a fun run for kids. Call 643-2090 or 703-494-5146.

UPTOWN RACES -- On May 10 to benefit Janney Elementary School; an 8K race and children's fun run through the streets of upper Northwest beginning at 8 a.m. Call Jay Silberman, 244-0808 or Steve Rottier, 966-9463.

FAIRFAX CITY 10K -- 8:30 a.m. on May 10 at Fairfax High School. Awards to top finishers in several age categories, including 19 and under. Call 385-7858.

FAUQUIER COUNTY 10K -- On May 10 at 9 a.m. at Airlie Plantation. Awards to top finishers in several categories, including 12 and under and 13 to 17. Call 703/349-1910.

HEALTHY CHOICES 10K, 5K & FUN RUN -- On May 11 at 8 a.m. from the Seventh Day Adventist Church on New Hampshire Ave in Spencerville, Md. Since it's Mother's Day, there will be special awards for mother-daughter teams, mother-son teams, mother-father teams and grandmother-mother-granddaughter teams. A health screening and veggie brunch will follow. Call 942-3206.

OTHER OPPORTUNITIES -- The following clubs and groups have regular family runs and fun runs and welcome family members:

FLEET FEET -- Five-mile fun runs Sundays at 9 at 1840 Columbia Rd. NW. Call 387-3888.

THOMAS JEFFERSON RECREATION CENTER -- Arlington. Five- and three-mile fun runs every Saturday at 8 a.m. Call 553-8522.

WAKEFIELD WADDLERS -- 10K around Lake Accotink at 7:30 a.m. Saturdays from the Wakefield Recreation Center. Call 455-4190.

D.C. ROAD RUNNERS CLUB -- Send SASE to DCRRC, Box 1352, Arlington 22210. Call 474-7177.

POTOMAC VALLEY SENIORS -- Send SASE to 1918 Storm Drive, Falls Church, Va. 22043. Call 703/790-8221.

PRINCE GEORGE'S RUNNING CLUB -- Send SASE to Box 321,Greenbelt, Md. 20770. Call 301/577-5576.

RESTON RUNNERS -- Send SASE to PO Box 2924, Reston, Va. 22090. Call 703/444-9215. WASHINGTON CLUB -- Send SASE to Box 2605, Springfield, Va. 22152. Call 703/455-0575.