Winter sledding tips.
D000056:Accident Prevention; D001265:Athletic Injuries / Q000209:etiology / Q000517:prevention & control*; D002648:Child; D002675:Child, Preschool; D003080:Cold Temperature; D005260:Female; D006801:Humans; D008297:Male; D010414:Pennsylvania; D012621:Seasons; D013177:Sports