Influence of the 4th COVID-19 related state of emergency declaration on the injury incidence among youth rugby players in Japan

Abstract

Several weeks of inactivity reduces athletes’ physical fitness and rugby-specific physical and mental preparedness for games and increases the risk of injuries. The purpose of our study was to compare the injury incidence among youth rugby players before and after the 4th COVID-19 related state of emergency declaration in Japan. The injury rate in the four-week post-declaration period (10.0/1000 athlete-exposure [AE], 95% confidence interval [CI]: 4.3-19.6) was not significantly different from the ten-week pre-declaration period (7.6/1000AE, 95%CI: 4.1-12.7) with an incidence rate ratio (IRR) of 0.8 (95%CI: 0.3-2.1). A comparison between the four-week post-declaration period and the period from week five through fourteen of post-declaration also did not result in statistically difference (IRR=0.9, 95%CI: 0.4-2.5). Neither the mode of injury onset nor the mechanism of injury in the four-week post-declaration period differed from those of the other periods. Subject of our study were likely to have maintained their physical condition during the voluntary stay-at-home period.