2.3.1. IMU

We used Perception Neuron 2.0, a low-cost IMU developed by Noitom, to capture Baduanjin motion data of participants [31]. This IMU includes 17 inertial sense units and each unit comprised a 3-axis gyroscope, 3-axis accelerate, and 3-axis magnetometer, which measures and records the rotation angle data of 17 position points of human movement. Sers et al. [32] compared the IMU used in our study with a gold standard optoelectronic system (Vicon), and confirmed the IMU's e ffectiveness in measuring motion accuracy. The supporting software of the IMU, Axis neuron software developed by Noitom, transforms the recorded data into Biovision Hierarchy (BVH) motion files.

#### 2.3.2. Capturing Motion Data

Before measuring the motion data, the teacher and senior students practised Baduanjin for 30 min. As the novice students had not learned Baduanjin, they followed the demonstration of the teacher practising Baduanjin for 30 min. After the practice, the motion data of participants were measured by IMU. No feedback was given to students during practice.
