On my limited Taiji/Qi Gong experience, the only thing I would say is relaxed != internal. Internal arts require a lot of energy.
The best explnation is from Tim Cartmell of internal/external, a man with a lot of martial arts experience, in particular with Neijia arts. http://www.shenwu.com/Internal_VS_External.htm
"Let your food be your medicine, and your medicine be your food"