Eight pieces, or Baduanjin, is a form of Chinese Qi Gong that is practiced to enhance one's physical health and mental calmness.
Interestingly, lots of ancient Chinese exercises such as Qi Gong and Tai Chi are forms of moving meditation used to stretch the body and calm the mind.
There has been a traditional discrepancy between training the mind and the body.
If you want to improve your physique, doing cardio exercises and training your muscles would be the most efficient; when it comes to training the mind, people usually turn to classic meditation techniques.
Interesting thing is, exercises like jogging release dopamine and enhance one's mood, but it is not as efficient in terms of soothing one's mind while at the same time sitting meditation has no muscular benefits. This is why the Shaolin temples invented their martial arts skills to counter the physical effect of prolonged meditation. Qi Gong seems to have reconciled exercising the body and mind together.