Exercise training protocol
Individuals in the DEx group performed a 6-month combined Yijingjing and resistance training under the guidance of a professional Yijinjing instructor, five times/week for 6 months, while NC and DC group remained previous daily routines. The exercise intervention was conducted in Gongnong Park of Shanghai Yangpu district which was close to the subjects’ home from April to December, 2021. Yijinjing of Li Wei’s version was used in this study which was promoted by the General Administration of Sports of China with about 13 minutes. The type of resistance training used in this study was elastic bands exercise with about 8 minutes. All elastic bands were purchased from Li-Ning (China) Sports Goods Co., Ltd. The overload of elastic bands was 35 pounds (1500 mm x 1500 mm x 0.5 mm) for men and 25 pounds (1500 mm x 150 mm x 0.4 mm) for women. The exercise intensity was maintained at 60%-70% of the maximum heart rate with polar watches. Each exercise session consisted of a 5 min warm-up, Yijinjing training, elastic bands training and a 5 min cool-down period. The duration of exercise was increased from 47 minutes to 76 minutes per session. Briefly, in the first two month, two sets of Yijinjing training and two sets of elastic bands training were performed, with a total of 47 minutes per session. In the third and fourth month, three sets of Yijinjing training and three sets of elastic bands training were performed, with a total of 68 minutes per session. In the fifth and sixth month, three sets of Yijinjing training and four sets of elastic bands training were performed, with a total of 76 minutes per session.