AUTO RACING

Costly wreck forces Junior off pole for Daytona 500

Dale Earnhardt Jr. wrecked his pole-winning car in practice Wednesday and will have to start at the back of the pack for the Daytona 500.

Earnhardt was pushing Hendrick Motorsports teammate Jimmie Johnson in practice when Johnson had to slow down for slower-moving traffic in front of him. Earnhardt plowed into Johnson’s back bumper and turned him sideways.

A second pack of cars led by Martin Truex Jr. closed quickly on Earnhardt’s bumper, causing the No. 88 Chevrolet to spin across the track and into the inside wall.

Johnson said he had to slow down suddenly when a pack of three cars ahead of them on the track — driven by Robby Gordon, Michael Waltrip and David Gilliland — drifted high from the bottom of the track toward the top.

Hendrick Motorsports immediately pulled out a backup car for Earnhardt. He will have to forfeit the top starting spot in his qualifying race today and Sunday’s season opener.

• Hendrick Motorsports signed 15-year-old Chase Elliott to a driver development deal.

Elliott, the son of 1988 NASCAR champion Bill Elliott, will receive support as he drives Chevrolets for Bill Elliott Racing until he turns 18 and is eligible to run in NASCAR national series events.

CYCLING

ARMSTRONG MAKES IT FINAL: Lance Armstrong said he’s leaving professional racing behind for good almost a month after finishing 65th in his last competitive race in Australia, and nearly six years removed from the last of an unprecedented seven straight Tour de France titles.

PREP SCHOOLS

BOYS’ HOCKEY: Shane Hearn had two goals, including the winner, and Guillaume Belanger Therien made 27 saves to lead Hebron Academy to a 4-3 victory over visiting New Hampton School.

GIRLS’ BASKETBALL: Stephanie DeSoto scored 18 points to lead Beaver Country Day School (15-2) to a 46-37 win over Berwick Academy (3-14) at South Berwick.

Juliana Blais led Berwick with 17 points and 11 rebounds.

GIRLS’ HOCKEY: Molly Strabley had two goals and an assist and Mariah Farrell made 20 saves to lead North Yarmouth Academy to a 3-2 win over Kents Hill at Yarmouth.

ROAD RACING

BOSTON MARATHON: Boston Marathon organizers announced changes to their registration system to ensure the fastest runners have spots at the starting line.

The move by the Boston Athletic Association comes after this year’s field filled up in just eight hours, frustrating qualified runners who were left out.

Starting with the 2012 marathon, the association will begin a two-week online registration period that gives those with the best times multiple chances to apply before opening it to slower runners.

TENNIS

OPEN 13: Sixth-seeded Jo-Wilfried Tsonga of France rallied to beat Sergiy Stakhovsky of Ukraine 5-7, 6-4, 6-2 in the second round at Marseille, France.

Fourth-seeded Jurgen Melzer of Austria beat Andreas Seppi of Italy, 7-5, 6-3.

COPA CLARO: Fourth-seeded Albert Montanes of Spain reached the quarterfinals by beating Fabio Fognini of Italy 6-2, 4-6, 6-4 at Buenos Aires, Argentina.

DUBAI CHAMPIONSHIPS: Russian Anna Chakvetadze collapsed on the court and had to retire from her match against top-seeded Caroline Wozniacki of Denmark at Dubai, United Arab Emirates. Organizers said Chakvetadze, who lost the first set 6-1, had a stomach illness.

In other matches, Yanina Wickmayer of Belgium upset Australian Open finalist and fifth seed Li Na, 6-7 (6), 7-6 (6), 6-2.

REGIONS MORGAN KEEGAN CHAMPIONSHIPS: Lleyton Hewitt defeated seventh-seeded Yen-Hsun Lu 6-4, 7-6 (3) in the first round at Memphis, Tenn.

In the women’s event, No. 3 Melanie Oudin was eliminated by Evgeniya Rodina, 6-1, 7-5.