On the friction of skis.
D000056:Accident Prevention; D001265:Athletic Injuries / Q000209:etiology / Q000517:prevention & control*; D004738:Engineering; D006801:Humans; D007869:Leg Injuries / Q000209:etiology / Q000517:prevention & control*; D008153:Lubrication; D009038:Motion; D012865:Skiing; D013696:Temperature