The Olympics, Curling and Doping. Really!?

Clearly, I’m missing something here. An Olympic curler has been accused of doping. Is there a rigorous activity I’ve overlooked? Some nuance that has escaped my eagle-like eyes? Let’s see,

Curling: One person shoves a flat rock-thing across an icy surface, then stares at it intensely. Then, two other people try and stay ahead of it as it moves slowly across the ice, sweeping the rock-thing’s desired path with brooms, hoping it will stop where they want it to. Oddly, it reminds me of shuffleboard; without the senior citizens.

Did I miss anything? It seems that at worst, you might fall on your ass or get a splinter from the broom.

Doping? I hope not.