OBJECTIVES: Physical restraint in the prone position is still utilized in healthcare facilities to immobilize violent patients. It is associated with the sudden death of violent patients. The aim of this study is to objectify the impact of physical restraint in the prone position on spirometric and ventilatory parameters. DESIGN: A pilot simulation study. MATERIAL AND METHODS: Ten university students were included in the study. They underwent two types of physical restraint: in the prone position with "chest kneeling" and in the lateral position. Spirometric parameters (FVC, PEF and FEV1%) and ventilatory parameters (EtCO2 and respiratory rate) were measured before initiation and after five minutes of physical restraint. RESULTS: Both methods of physical restraint resulted in a decrease in FVC (p = 0.005 or p = 0.047) and PEF (p = 0.005 or p = 0.028). No significant changes were observed in EtCO2 and respiratory rate. CONCLUSION: Physical restraint in the prone position should not be used in healthcare.