Water polo, or Water ball, is a team water sport. The playing team consists of six field players and one goalkeeper. The winner of the game is the team that scores the most goals. Game play involves swimming, treading water (using a sort of kicking motion known as "eggbeater kick"), players passing the ball while being defended by opponents, and scoring by throwing the ball into a net defended by a goalie. 'Man-up' (or 'power play') situations occur frequently. Water polo, therefore, has strong similarities to the land-based game of handball.

Seven players from each team (six field players and a goalkeeper) are allowed in the playing area of the pool during game play with up to four substitutes. Visiting team field players wear numbered and usually White caps, and home team field players wear usually Blue caps (though any other contrasting colors are now allowed); both goalies wear red caps, numbered "1". Players may be substituted in and out after goals, during timeouts, at the beginning of each quarter, after ordinary fouls and after injuries. During game play, players enter and exit in the corner of the pool, or in front of their goal; when play is stopped, they may enter or exit anywhere.

Wolf Wigo (born May 8, 1973 in Abington, PA) is a renowned American water polo player and coach. He has played competitive water polo at the national level since age 13, was a four-year All-America collegiate player and led his Stanford University team to two NCAA Championships. A member of the U.S. National Team since 1993, Wigo competed in the Olympic Games in 1996, 2000 and 2004, was leading team scorer in the 2000 Sydney games and team captain from 2001-2004. Since 2005, he has been the head coach of the UC Santa Barbara men's water polo program. And starting in 2008 he will be coaching the UCSB women's team as well.

Wigo's parents were both swimmers so at an early age he and his sister would travel to the pool at the West Side Y in New York City and compete with the Gotham Aqua Kings. After success in swimming (he was named “Swimmer of the Decade” at New York’s Bronx High School of Science), Wigo took up water polo because he enjoyed the team spirit and competition. He played on the St. Francis College Youth Water Polo Club in Brooklyn Heights, New York. By age 13, he was the youngest player on the New York Athletic Club team, earned back-to-back NYAC Utzinger Awards, and was a Prep All-American three years in a row. While still in high school, Wigo was a member of the only 17-and-under team from outside California to win the national Junior Olympics in water polo.