A day after U.S.A. Gymnastics appointed an interim leader to help move the sport beyond months of tumult and scandal, the organization again found itself embroiled in controversy on Saturday — and facing criticism from one of the sport’s biggest stars.

The new leader, Mary Bono, came under fire for an anti-Nike tweet that she posted in September, days after the company announced an ad campaign featuring Colin Kaepernick, the former N.F.L. quarterback who knelt during the national anthem to protest racial inequality and police killings of black people.

As critics pledged to boycott Nike products, Ms. Bono shared a photo of herself using a marker to black out the Nike logo on her golf cleats.

Simone Biles, who won four gold medals and a bronze at the 2016 Olympics and who will compete for the United States in this year’s world championships, resurfaced the tweet with a critical post of her own on Saturday.