Don't take it personally but I may be shocked by your response here; Do you think it's normal for an 11 year old girl to sit around and play with their phone or watch TV? It may be common but normality is another question. Around puberty, before their growth spurt, kids should be getting a little fat or at least eating endlessly. Their heart, lungs, and hormones, and hands, feet and ears are all already grown too big, meant to support their adult selves. "You'll grow into it" we say. They have athletic super powers at this stage and at least when we were growing up, kids and dog would run for 12 hours as soon as you forget to lock the gate.
I think it's possible she's just being a kid and found a way to use her growing energy in a time and place where we don't get kids wander the woods all day anymore. Where there could be a problem is if she thinks she's fat and becomes obsessive and harmful to herself though her diet practices, which may also tend to manifest at this stage. There's a find line between a party animal and a raging drunk. The determination is made by determining intent.