AmericanFootballisatoughcontactsportthatdominatestheAmericansportingsceneandisgainingpopularityinEurope.Itisagamerequiringall-roundphysicalfitness.Playershavetobefast,strong,andproficientinthesixbasicskillsoffootball:passing,catching,running,blocking,tackling,andkicking.Americanfootballhasalwaysbeenassociatedwithalargenumberofinjuries,notsurprisingwhenthegamecommonlyinvolvesplayersinexcessof240poundscollidingwitheachotheratfullspeed.IntheUnitedStates,itisestimatedthatmorethan300000highschoolplayers,35000collegeplayers,andhalfoftheNationalFootballLeagueplayersareinjuredtosomeextenteachseason.Headandneckinjuriesarecommon:thereareapproximately250000incidentsofconcussioneachyear.Someinjurieshavebeenfatalorhaveresultedinplayersbecomingpermanentquadriplegics.However,thenumberofverysevereinjurieshasdeclinedinrecentyears.Thisisprobablyduetorulechangesconcerningtacklingandblockingwiththehead,andimprovementsinprotectiveequipmentwhichwereintroducedin1976.Therehasalsobeenagreateremphasisintrainingonstrengtheningthemusclesoftheneckandlearninggoodtacklingtechniques.Thisisparticularlyimportantintheyoungeragegroup. 　　Protectiveclothingisanessentialfeatureofmodernfootball,butthismakestheplayersvulnerabletoheatstroke.Onestudyreported12heatstrokedeathsamongcollegeandhighschoolfootballplayersoverathreeyearperiod.Thevictimswereallinteriorlinemen,probablytheplayersrequiredtoworkhardestandlongest;mostwerestrickenduringpre-seasonpracticesotheymayhavebeeninpoorphysicalcondition;allweredressedinfulluniformswhichincreasesworkloadandinterfereswithheatloss;andmostwerenotpermittedtodrinkwaterduringpractice.Clearly,itisessentialthatplayersandofficialsshouldbeawareoftheriskofheatstroke,andensurethatdrinkingwaterisavailableduringpracticeandgames.