Sit-ups are such a standard strength-training exercise, you never think you could be seriously injured doing one. But that's what happened to a 23-year-old Brazilian law graduate and fitness model—and her recovery has been nothing short of miraculous.

In January 2016, Marcelle Mancuso was at the gym doing inverted sit-ups (which means your ankles are in the air high and your head lower near the floor) while strapped into a bench. A trainer who was spotting her also held her feet as she did her sit-ups.

“The band that held my feet broke and I hit my head on the floor, breaking the cervical spine and immediately became tetraplegic,” she tells Health. “I lost all movement from the neck down.”

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Also referred to as quadriplegia, tetraplegia is the paralysis of both the upper and lower parts of the body—including the fingers, hands, arms, chest, legs, feet, and toes. Tetraplegia can also limit mobility of the head, neck, and shoulders, states the University of Alabama School of Medicine. 

After the injury, which left her without the use of her arms and legs, Mancuso says that doctors put a titanium plate and six screws in her neck to realign her spine.

“The doctors did not know if I would walk again,” she says. “I was scared but I fought. I have been resilient and dedicated myself every day to my physiotherapy.”

Mancuso had to learn how to walk and even feed herself all over again, but she eventually managed to recover and return to the gym. Today, she says she leads a “normal and independent life,” and can walk, run, jump rope, and swim.

"I thank God every day for that,” she says of her miraculous recovery. As for her sit-up routine, she tells us that she's done with the inverted kind. "I do sit-ups but only on the ground, lying flat!" she says.