Water skiing is a surface water sport in which an individual is pulled behind a boat or a cable ski installation over a body of water, skimming the surface on two skis or one (slalom) ski. The sport requires sufficient area on a smooth stretch of water, one or two skis, a tow boat with tow rope, three people, and a personal flotation device. In addition, the skier must have adequate upper and lower body strength, muscular endurance, and good balance. Skiing is a fun pastime that allows people of all skill levels and ages to enjoy. There is no minimum age necessary to water ski.