TENNIS

AZARENKA, SAFAROVA, STOSUR ADVANCE AT QATAR OPEN: DOHA, Qatar (AP) — Top-ranked Victoria Azarenka defeated Simona Halep of Romania 6-3, 6-1 to reach the Qatar Open quarterfinals, while Lucie Safarova stopped Svetlana Kuznetsova 7-6 (6), 6-3.

Third-seeded Sam Stosur took advantage of shaky serving from Petra Cetkovska for a 6-3, 6-2 victory in the third round and earned her first consecutive wins of the year.

Fourth-seeded Agnieszka Radwanska saved two set points in the first set and stopped Varvara Lepchenko of the United States 7-5, 6-1. American Christina McHale will play Radwanska in the quarterfinals after defeating Shahar Peer of Israel 4-6, 6-3, 6-4.

Azarenka fell behind 3-1 to Halep, then won eight straight games to lead by a set and 3-0. Azarenka finished the match with another break on a forehand winner down the line.

FOOTBALL

USA FOOTBALL TO CONDUCT INJURIES STUDY: INDIANAPOLIS (AP) — USA Football has commissioned a full-season research study this year to examine player health and safety in organized youth tackle football.

The independent study, to be conducted by the Datalys Center, is the first sponsored by football's national governing body in the United States, and is believed to be the first of its scope in youth football's 80-plus year history.

The research will look at any injuries sustained during the 2012 season in 10 youth football leagues across the nation. Athletic trainers will attend the leagues' practices and games to manage and document player health.

Approximately 3 million youngsters from ages 6 to 14 play organized tackle football.

"This ground-breaking research will enable us to strengthen youth football player safety in an evidence-based way," USA Football executive director Scott Hallenbeck said. "USA Football is committed to continue to lead America's football community and discover how our country's favorite sport can be made even better."