Due to the spread of COVID-19, it is now mandatory to wear a mouth-covering mask within one’s traditional face mask when practicing kendo with another person. Using a plastic face shield inside the kendo mask is also recommended to prevent the spread of droplets during vocalization. However, no study has investigated the effects of wearing a facial mask on the safety of individuals during Kendo. Thus, this study aimed to elucidate the effects of wearing a facial mask on the saturation of percutaneous oxygen (SpO2) during Kirikaeshi, one of the traditional Kendo practices.
Participants were eight male college students training in kendo with no noteworthy illnesses or injuries. Each par ticipant carried out a masked trial while wearing a mask and a controlled trial on separate days while no wearing a mask. SpO2, heart rate (HR), and rating of perceived exertion (RPE) were measured at rest and immediately after completing five sets of kirikaeshi. The results showed that SpO2 decreased after the experiment compared to before in both conditions, but only significantly in the mask trial. After kirikaeshi, a significant increase in HR was observed, but there was no significant difference in post-kirikaeshi HR between the masked and controlled. No significant differences in post-kirikaeshi RPE were observed between the masked and controlled. These findings suggest that despite causing no subjective symptoms, wearing a mask during kendo practice decreases SpO2 and may put athletes at risk of hypoxemia and symptoms similar to altitude sickness (e.g., headache, dizziness, lightheadedness). It is, therefore, necessary to take more care in ensuring safety for each individual’s physical condition when practicing kendo with a mask.
