accidents, polo ponies may have the ability to play until they are 18 to 20 years of age. Each player must have more than one horse, to allow for tired mounts to be replaced by fresh ones between or even during chukkas. A player's "string" of polo ponies may number two or three in Low Goal matches (with ponies being rested for at least a chukka before reuse), four or more for Medium Goal matches (at least one per chukka), and even more for the highest levels of competition. Players Each team consists of four mounted players, which can be mixed teams of both men and women. Each position assigned to a player has certain responsibilities: Number One is the most offence-oriented position on the field. The Number One position, which generally covers the opposing team's Number Four, is usually the rookie of the team. Number Two has an important role in offence, either running through and scoring themselves, or passing to the Number One and getting in behind them. Defensively, they will cover the opposing team's Number Three, generally the other team's best player. Given the difficulty of this position, it is not uncommon for the best player on the team to play Number Two so long as another strong player is available to play Three. Number Three is the tactical leader and must be a long powerful hitter to feed balls to Number Two and Number One as well as maintaining a solid defense. The best player on the team is usually the Number Three player, usually wielding the highest handicap. Number Four is the primary defense player. They can move anywhere on the field, but they usually try to prevent scoring. The emphasis on defense by the Number Four allows the Number Three to attempt more offensive plays, since they know that they will be covered if they lose the ball. Polo must be played right-handed to prevent head-on collisions. Equipment The rules for equipment vary in details between the hosting authorities, but are always for the safety of the players and mounts. Mandatory equipment includes a protective helmet with chinstrap worn at all times by all players and mounted grooms. They have a rigid exterior and interior protective padding and must be to a locally accepted safety standard, PAS015 (UK), NOCSAE (USA). A faceguard is commonly integral with the helmet. Polo boots and kneeguards are mandatory