Data collection The participants were divided into two groups by random drawing. Each performer in the first group knelt on the kneeling stool beside the manikin on a bed and compressed the chest of the manikin (CCs with a kneeling posture, PK).Each performer in the second group stood on a step stool beside the manikin on a bed and compressed the chest of the manikin (CCs with a standing posture, PS). When the performer stood beside the manikin on a bed, the height of the manikin's back was adjusted in height to the knee level of the provider using the step stool and the bed height adjustment mechanism. All the participants performed continuous CCs for 5 minutes without audio-visual feedback. After 2 weeks, the posture used for the CCs by each group was changed. Each participant recorded his/her fatigue and pain levels on a visual analogue scale (VAS, score 0 indicates "no pain and fatigue" and score 10 indicates "unbearable pain and fatigue") for each minute during 5 minutes of CCs. After conclusion of the experiment, the participants selected a preferred CC posture in terms of the safety and the quality of the CCs.