Both plan to be ready when the Olympics begin Friday.
The 16-year-old Maroney did a few warmup vaults Tuesday and the dance elements in her floor exercise routine. But she did not do any of her tumbling runs on floor and spent most of the roughly 90-minute session on a chair, watching her teammates.
The Americans did not talk after practice. USA Gymnastics said Maroney is resting her right foot. She walked gingerly toward a bus when practice ended.
It's unclear when the foot problem arose. Maroney shook off a concussion from the national championships in June to win the vaulting title at the Olympic trials and land a spot on the U.S. team this month.
The women's competition begins Sunday, and the Americans are heavy favourites to add Olympic gold to the world title they won last fall. It's a medal Maroney helped land thanks to her signature event, where she is one of a handful of competitors who can complete the difficult Amanar. The move requires a round-off then a back handspring onto the table before completing 2 1/2 twists.
When done well, the vault — which can be done by all five of the Americans on the team — gives the U.S. a significant advantage over the competition and no one on the planet can match Maroney's explosiveness. She roared to a world title in Tokyo last October and reaffirmed her dominance at the trials.
The women practice again on Wednesday and have until Friday to make any changes to the lineup.
While Maroney hung out, U.S. men's team member Mikulak worked out. The 19-year-old practiced several events on Tuesday with his sprained left ankle heavily taped.
He turned the ankle while vaulting during the first day of Olympic trials, a night when he actually beat national champion John Orozco and reigning world parallel bars champion Danell Leyva in the all-around.
Mikulak competed in just one event during the finals two days later, but U.S. officials placed him on the team anyway. He spent the last month aggressively treating the injury — a problem that began last year when he broke both legs during a meet in Puerto Rico.
Mikulak is one of the best Americans on pommels — a notoriously weak event for the U.S. — and parallel bars. The men begin podium training at the O2 Arena on Wednesday and have until Thursday to set their roster for qualifying.
AP National Writer Nancy Armour contributed to this report. Follow Will Graves on Twitter at www.twitter.com/WillGravesAP