Self-driven training
The trainees in the self-driven training group were provided with a training video with a voice-over recorded by Yu-tang Ren and training slides provided by Wei-guang Qiao, which were similar to those that were used for teaching in the interactive training group. They reviewed the teaching material individually. The trainees could view the slide presentation and training videos at any time within a 40 min timeframe. To make sure the training materials were actually accessed and reviewed by the trainees, a slide with a QR code used for after-training tests was set as the last page.