Two or more significant blows to the head while playing sports can harm teenagers' thinking abilities for years to come, according to studies that suggest such injuries are more serious than some coaches and parents might think.

Nearly 63,000 high school athletes a year suffer mild concussions, researchers reported in yesterday's Journal of the American Medical Association. Young athletes with learning disorders appear to suffer even worse long-term problems from multiple concussions.

"This is a major public health issue that has been given short shrift," said Michael W. Collins, a neurophysiologist at Henry Ford Health System in Detroit and a leader of one of the studies. "And this is information parents should know."

Most people still believe that a concussion means getting knocked out, he said. But a concussion is any alteration in mental function after a blow to the head. Signs or symptoms may be subtle--a headache, dizziness, difficulty with balance or memory, confusion or a personality change.

One of the studies did not explore the effects of concussions but only how often they occurred in football, wrestling, soccer, basketball, softball, baseball, field hockey and volleyball at 235 high schools nationwide from 1995 to 1998.

There were 1,219 concussions--63 percent of them in football--and 99 students suffered two or more, said researchers led by John W. Powell, a professor of kinesiology and an athletic trainer at Michigan State University.

Olympics

Baseball in Greece

Plans to bring baseball to Greece before the 2004 Olympics moved forward when Baltimore Orioles owner Peter Angelos met with Greek officials to try to put together a team in a nation without a baseball park.

"We're going to get it done, but it's going to be a challenge," Angelos said during a reception held by U.S. Ambassador Nicholas Burns and the Hellenic Amateur Baseball Federation.

Angelos, a Greek-American who is heading the group, is being helped by the commissioner's office and the Boston Red Sox--Burns's favorite team. Angelos hopes to have a delegation, including players and player development personnel, in Greece later this year.

As host nation of the Olympics, Greece automatically qualifies to enter a team in every sport. Greek organizers hope to build their first baseball team from Greek-Americans.

Presently, the only regulation baseball diamond in Greece is on a closed U.S. military base outside Athens. . . .

Dot Richardson and seven other veterans of the 1996 U.S. Olympic softball team will get a chance to play for a second gold medal in Sydney next year.

The Amateur Softball Association/USA Softball announced the roster Monday, concluding a three-year selection process.

Led by Richardson, a 37-year-old second baseman and orthopedic surgeon, the United States won the inaugural women's Olympic tournament.

Joining Richardson of Orlando as repeat members are outfielders Laura Berg of Santa Fe Springs, Calif., and Leah O'Brien-Amico of Chino, Calif; first baseman Sheila Douty of Diamond Bar, Calif.; and pitchers Lisa Fernandez of Long Beach, Calif., Lori Harrigan of Las Vegas, Michele Smith of Califon, N.J., and Christa Williams of Houston.

The team's first game will be Friday against New Zealand in the inaugural U.S. Olympic Cup in San Diego.

Soccer

France, England Out?

The field for the 2000 European championships should become clearer today--and World Cup champion France and England are in danger of not qualifying.

The Czech Republic and hosts Belgium and the Netherlands already are ensured spots in the 16-nation tournament next summer. Italy, Spain, Sweden, Norway and Romania will join them with victories.

But if England and France lose, the English definitely will be out and the French will have only a mathematical chance of survival.

That means stars such as David Beckham, Michael Owen, Zinedine Zidane and Didier Deschamps could be idle when the European title is decided.

France is home against Iceland, and Poland is home against England. England and Poland are even on points but the Poles have a game in hand so Kevin Keegan's team has to win to survive. . . .

Asia gave up on its bid for a fifth spot in the 2002 World Cup, accepting a compromise in which it will get four berths and a chance for a fifth in a playoff. . . .

Joe-Max Moore sparked New England's comeback from a two-goal deficit in the second half, scoring the go-ahead goal in the 88th minute to lift the Revolution to a 3-2 victory over the Kansas City Wizards at rainy Foxboro (Mass.) Stadium.

New England (10-17, 22 points) moved into a tie with Miami for the final playoff spot in the Eastern Conference with five games remaining. Moore assisted on goals by Giovanni Savarese in the 67th and 81st minutes, then scored his 13th goal of the year.

Preki Radosavljevic and Chris Henderson scored for Kansas City (8-19, 20 points).

Cycling

Claveyrolat Kills Self

Former French cyclist Thierry Claveyrolat, who won the King of the Mountains title in the 1990 Tour de France, committed suicide at home in the French village of Vizille, police said.

Claveyrolat, 40, left a suicide note to his wife, which she found yesterday morning. She immediately called the police, who found his body in a locked shed in the garden. Claveyrolat had shot himself.