Qigong is an Internal Art. What you see on the outside when someone is performing Qigong is someone either standing still or doing some relaxed, simple movements. All in all it all looks fairly benign and unremarkable. Unless you are the person performing the Qigong itself!
On the inside it is a completely different thing that is happening. The Qigong practitioner is going on a journey to the inside, many different energy movements are happening in the marvelous subtle energy system of the body, the organs are being activated and replenished and the practitioner is also sensing the energies on the outside of the body and how they interact with the inside.
All of this happens during the simple movements or stillness of the practitioner. The practitioner may also look in a very sedated or quiescent state but this quiescence has a very active aspect: The practitioner is full of energy yet in a fully relaxed state. Yin and Yang are replenished and balanced.