Randomization and blinding
Using computer-generated randomization, trainees were assigned 1:1:1 to receive either traditional training method (TM group) or OSP-TCM training method (OSP-TCM group) or SSP-TCM training method (SSP-TCM group). An independent investigator carried out the randomization. The assignment and all baseline measures were confidential to the trainees, researchers and study staff involved in this study. Independent study analysts were blinded to collect data during the study period, and the data analysis could not be performed until the data collection was complete.