The new mother of twins, 36, shared a video of her workout on Instagram Monday, showing off her extension stretches. “#monday #backatit,” Kournikova captioned the footage along with a flexed bicep emoji.
The tennis pro and longtime partner Enrique Iglesias, who have been together for over a decade and a half, welcomed twins —a boy and a girl named Nicholas and Lucy— in December in Miami.
The newborn babies are the first children for both Iglesias, 42, and Kournikova.
Kournikova’s workout clip comes weeks after the proud parents shared adorable first photos of their twins on Jan. 16.
The “El Baño” singer snuggled up to son Nicholas, who sported a gray striped onesie and matching hat while the mother of two posted a photo of herself kissing baby girl Lucy’s cheek.
And the pair isn’t the only ones gushing over the new additions.
Iglesias’ mother, Isabel Preysler, gushed about her grandchildren’s bond with their father to Hola magazine, saying, “Enrique is extraordinarily happy.”
About Kournikova’s low-key pregnancy, Preysler recalled: “It was a perfectly normal pregnancy, she didn’t have to do mandatory bed rest at any time. Anna hasn’t had to hide. She has a very simple and homey life.”
In addition, Enrique’s sister, Tamara Falcó Preysler, also told the publication that her niece and nephew already have distinct similarities to their parents.
“Lucy looks more like Anna, she is blonde and has blue eyes, and Nico looks more like Enrique, more morenito [a little darker],” she said.
This article originally appeared on PEOPLE