Such growth has led to a collision of ideals. Local runners say Wittenberg’s expanding ambitions have eroded the ethos of Road Runners to serve athletes in New York. She has destroyed the intimacy of what started as a modest grass-roots club for like-minded runners, they say.

In what seems to be a double-edged victory, more runners than ever are registering for Road Runners races, but some races sell out or are as crowded as the Coney Island boardwalk on a summer day. Rising entry fees have priced out lower-income runners and alienated some longtime Road Runners members.

Gary Meltzer, who was voted off the board after Wittenberg became the chief executive, said the club had become “way too corporate,” with board members chosen for their professional backgrounds rather than love of the sport.

In three weeks, nearly 50,000 runners are expected to gather at the foot of the Verrazano-Narrows Bridge on Staten Island to begin this year’s New York City Marathon. When Wittenberg took over, the cost to run the 26.2-mile, five-borough tour of New York was $80 for Road Runners members. This year, it was $216 for members. For nonmembers from the United States, it was $255, more than $100 more than the fee for any of the four other major world marathons and nearly five times the cost of the London Marathon alone.

“Ten years ago, 12 years ago, we only had serious runners, and it was never an option for me to be the way we were then,” Wittenberg said. “And it’s not an option to be the way we are right now. We’re not sorry we’re successful. To our critics, we say, we want you to come along.”

Living at a Frantic Pace

To come along, it is best to wear sneakers, because Wittenberg sprints through her days.

At 8:15 a.m. on Sept. 22, inside her two-bedroom apartment on East 78th Street, she had been up for two hours, tending to her two young sons and answering e-mails, before heading to the Fifth Avenue Mile races.