BACKGROUND Anterior cruciate ligament(ACL)injuries represent detrimental injuries in the National Football League(NFL).A significant portion of these injuries often occur in preseason exhibitions.The Coronavirus disea...BACKGROUND Anterior cruciate ligament(ACL)injuries represent detrimental injuries in the National Football League(NFL).A significant portion of these injuries often occur in preseason exhibitions.The Coronavirus disease 2019 pandemic presented a unique disruption to preseason NFL football with the cancelation of all preseason games.AIM To compare the incidence of ACL tears through the first eight weeks of the NFL season in 2020 to the mean incidence over the previous 5 seasons(2015-2019)and determine if there was any change in incidence with the elimination of the preseason.METHODS NFL players who suffered ACL tears during the preseason and first eight weeks of the NFL season from 2015-2020 were identified.The number of ACL injuries for the 2015-2019 seasons was compared to the 2020 season for four different timeframes.For each analysis,the cumulative number of ACL injuries to that time point was used to calculate the percent difference for descriptive analysis.Additionally,the number of teams with at least one player suffering an ACL tear were identified and compared using Chi-Squared testing.Finally,a cumulative relative risk was calculated for each week played.RESULTS There were 14 ACL tears through the first four games of the 2020 season,a 118.8%(14 vs 6.4)increase in comparison to the 5-year average over the first 4 regular season weeks of 2015-2019.However,when accounting for injuries occurring during the preseason from 2015-2019,there were 18.6%(14 vs 17.2)fewer total ACL injuries through regular season week 4 with no significant difference in percentage of teams impacted when these preseason injuries were accounted for P=0.394.Results were similar(19 vs 17.2)over 8 total games played(whether regular season or preseason),and over 8 regular season games(P=0.196,P=0.600).CONCLUSION The elimination of the NFL preseason resulted in a higher rate of injuries during the first 4 games of the regular season.However,these increases are offset by the injuries typically sustained during the preseason.This suggests there may be front-loading of injuries over the course of an NFL season,such that players may be more prone to injury when the intensity of play suddenly increases,whether in the preseason or regular season.展开更多
Although the North Atlantic(NA)hurricane season has been reported to start increasingly early,historical longterm changes in NA spring tropical cyclone(TC)activity have not been examined in previous studies.We find th...Although the North Atlantic(NA)hurricane season has been reported to start increasingly early,historical longterm changes in NA spring tropical cyclone(TC)activity have not been examined in previous studies.We find that spring TCs have become more frequent and intense,and they have more closely approached the US coastline over the past four decades,thus increasing the probability of landfall.A long-term increase in the NA sea surface temperature(SST)and northward incursion of warm water may be responsible for the increasing number,intensity,and northward shift of spring TCs.In addition,the interdecadal winter NA SST tripole mode may induce a North Atlantic Oscillation(NAO)-like atmospheric response in the following spring,which controls spring TC tracks via modulating the strength and position of the NA subtropical high(or the Bermuda high).The superposition of the interdecadal positive winter SST tripole on the NA warming trend has contributed to the anomalous enhancement and northward shift of spring TC activity,increasing the spring TC risks in the US in the past six years.展开更多
文摘BACKGROUND Anterior cruciate ligament(ACL)injuries represent detrimental injuries in the National Football League(NFL).A significant portion of these injuries often occur in preseason exhibitions.The Coronavirus disease 2019 pandemic presented a unique disruption to preseason NFL football with the cancelation of all preseason games.AIM To compare the incidence of ACL tears through the first eight weeks of the NFL season in 2020 to the mean incidence over the previous 5 seasons(2015-2019)and determine if there was any change in incidence with the elimination of the preseason.METHODS NFL players who suffered ACL tears during the preseason and first eight weeks of the NFL season from 2015-2020 were identified.The number of ACL injuries for the 2015-2019 seasons was compared to the 2020 season for four different timeframes.For each analysis,the cumulative number of ACL injuries to that time point was used to calculate the percent difference for descriptive analysis.Additionally,the number of teams with at least one player suffering an ACL tear were identified and compared using Chi-Squared testing.Finally,a cumulative relative risk was calculated for each week played.RESULTS There were 14 ACL tears through the first four games of the 2020 season,a 118.8%(14 vs 6.4)increase in comparison to the 5-year average over the first 4 regular season weeks of 2015-2019.However,when accounting for injuries occurring during the preseason from 2015-2019,there were 18.6%(14 vs 17.2)fewer total ACL injuries through regular season week 4 with no significant difference in percentage of teams impacted when these preseason injuries were accounted for P=0.394.Results were similar(19 vs 17.2)over 8 total games played(whether regular season or preseason),and over 8 regular season games(P=0.196,P=0.600).CONCLUSION The elimination of the NFL preseason resulted in a higher rate of injuries during the first 4 games of the regular season.However,these increases are offset by the injuries typically sustained during the preseason.This suggests there may be front-loading of injuries over the course of an NFL season,such that players may be more prone to injury when the intensity of play suddenly increases,whether in the preseason or regular season.
基金Supported by the Innovative Research and Development Project in Guangdong Province of China(2019ZT08G669)Science and Technology Planning Project of Guangdong Province(2018B020208004)+1 种基金Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Guangdong Basic and Applied Basic Research Foundation(2020A1515110275)。
文摘Although the North Atlantic(NA)hurricane season has been reported to start increasingly early,historical longterm changes in NA spring tropical cyclone(TC)activity have not been examined in previous studies.We find that spring TCs have become more frequent and intense,and they have more closely approached the US coastline over the past four decades,thus increasing the probability of landfall.A long-term increase in the NA sea surface temperature(SST)and northward incursion of warm water may be responsible for the increasing number,intensity,and northward shift of spring TCs.In addition,the interdecadal winter NA SST tripole mode may induce a North Atlantic Oscillation(NAO)-like atmospheric response in the following spring,which controls spring TC tracks via modulating the strength and position of the NA subtropical high(or the Bermuda high).The superposition of the interdecadal positive winter SST tripole on the NA warming trend has contributed to the anomalous enhancement and northward shift of spring TC activity,increasing the spring TC risks in the US in the past six years.
