Following the 2020 cardiopulmonary resuscitation (CPR) guidelines, this study compared participant's fatigue with the quality of manual chest compressions performed in the head-up CPR (HUP-CPR) and supine CPR (SUP-CPR) positions for two minutes on a manikin.Both HUP-CPR and SUP-CPR were performed in a randomized order determined by a lottery-style draw. Manual chest compressions were then performed continuously on a realistic manikin for two minutes in each position, with a 30-minute break between each condition. Data were collected on heart rate, blood pressure, and Borg rating of perceived exertion (RPE) scale scores from the participants before and after the compressions.Mean chest compression depth (MCCD), mean chest compression rate (MCCR), accurate chest compression depth ratio (ACCDR), and correct hand position ratio were significantly lower in the HUP group than that in the SUP group. However, there were no significant differences in accurate chest compression rate ratio (ACCRR), correct recoil ratio, or mean arterial pressure (MAP) before and after chest compressions between the two groups. Changes in heart rate and RPE scores were greater in the HUP group.High-quality manual chest compressions can still be performed when the CPR manikin is placed in the HUP position. However, the quality of chest compressions in the HUP position was poorer than those in the SUP position, and rescuer fatigue was increased.