Rita Jeptoo: IAAF wants Kenyan's doping ban doubled

Kenyan Rita Jeptoo has won the Boston Marathon on three occasions

Athletics' governing body has asked sport's highest court to double Rita Jeptoo's two-year doping ban.

But the Kenyan athlete has filed an appeal to the Court of Arbitration for Sport (Cas) seeking to overturn her punishment for failing a drugs test.

Jeptoo, 34, became Kenya's first high-profile athlete to fail a test when she tested positive for performance-enhancing drugs in September.

Athletics Kenya have suspended her from all competition until October 2016.

CAS has said the International Association of Athletics Federations (IAAF) wants a four-year ban because of "aggravating circumstances".

But Jeptoo, who says she may have been prescribed some banned substances at a local hospital after a road accident, is seeking a delay in the ban's implementation and hopes to compete in August's World Championships.