This was a prospective, randomized, simulation study that was conducted over 4 months, from November 2019 to February 2020, among second- to fourth-year paramedic students who had clinical practice at the Emergency Medical Center of a university-affiliated hospital. Those who voluntarily agreed to participate were included in the study. Participants were divided into 2 groups: men and women. In each group, the participants performed chest compressions on the Resusci Anne QCPR/SimPad PLUS with SkillReporter (Laerdal, Stavanger, Norway) in pairs. The total chest compression time was defined as 20 minutes assuming an in-hospital cardiac arrest scenario. In the 2-minute scenario, each participant was positioned opposite the other and performed chest compressions for 2 minutes, then took a 10-second break pretending to check the pulse and rhythm. Immediately after each chest compression, investigators measured heart rate using pulse oximetry and the degree of fatigue using questionnaires. This was repeated 5 times in 20 minutes. In the 1-minute scenario, each participant performed chest compressions for 1 minute and took a 10-second break every 2 minutes. This process was repeated 10 times in 20 minutes. After a 3-hour break, under the assumption of full recovery from fatigue, the participants in the 1-minute group crossed over to the 2-minute group and vice versa. In addition, to compare the quality of chest compressions over time, 1 set was performed for 4 minutes and 5 sets were performed in 20 minutes to compare parameters between the 2 groups. This was defined based on a minimum of 4 minutes taken for performing chest compressions by both sets of participants in the 2-minute group. All participants provided informed consent. The Institutional Review Board of the hospital reviewed and approved the specific procedures (CR-19-144).