BOSTON (AP) — The Boston Marathon is full.

The Boston Athletic Association said Thursday that registration for the 2013 race has closed. More than 20,000 runners who met a new, more difficult qualifying standard, signed up since registration opened Sept. 10.

Other runners still have a chance to participate as part of a charity program that has raised more than $150 million in the past 25 years.

The marathon was forced to change its registration process two years ago after a rush of applicants filled the field in eight hours. That broke the previous record of 65 days.