Regular exercise is mandatory for the proper maintenance and circulation of Qi. Activities such as Yoga or Tai Ji are aimed at developing Qi rather than just the muscles.
Health and fitness are two different things, and they generally do not overlap. Our definition of a “fit” person is someone that can sustain heavy exercise for longer than “average.” This does not always mean the person is healthy. The reason is physical exercise develops the muscles and sinews and does not nourish the internal organs.
Training programs which incorporate Qi Gong, Yoga, Tai Ji, etc. also use the muscles but nourish the internal organs to promote health from the inside out as well.