American gymnast Simone Biles said she abruptly stopped competing during the women’s gymnastics team final because she was dealing with mental problems. Biles, speaking to reporters after the United States was beaten by Russia, said she “just felt like it would be a little bit better to take a back seat, to work on my mindfulness.” Biles said she suffered no physical injury, despite Team USA saying earlier she was out due to “a medical issue.” “That’s why I took a step back, because I didn’t want to do something silly out there and get injured,” she said, calling the Olympics “really stressful.” “We had a workout this morning. It went okay. And then just that five and a half hour wait or something, I was just like shaking, could barely nap. I’ve just never felt like this going into a competition before and I tried to go out here …