The most popular version is field lacrosse. The playing field has goals that are 80 yards apart, with playing areas of 15 yards behind each goal. The width of the field is 60 yards. Each team has ten members: one goalie, three defensemen (who stay near the goal area), three midfielders (who cover the entire field), and three attackmen (who cover the area closest the opponent’s goal). The players use crosses with different length shafts and different width heads, but this is beyond the scope of this chapter. The hard rubber ball must be from 7 3/4 to 8 in., and weigh from 5 to 5 1/4 oz. The goal is 6 ft by 6 ft. Play is organized into four periods, each period lasting 15 minutes. If there is a tie at the end of regular play, the game continues into sudden victory. During sudden victory, 4-minute periods are played until one team finally scores. High school games are 48 minutes long, divided into 12-minute periods.

While attempting to prevent the opposing team from scoring, it is legal to apply body checks. Play is supervised by no less than two officials. A player is permitted to check in the following circumstances:

No other checks are legal, and a partial (most certainly not thorough) list of fouls should be discussed so as to better understand possible mechanisms of injury.

To help protect the players, certain protective equipment is mandatory, and some is optional. Required equipment for all players includes a helmet with a face mask and chin strap, mouthguard, shoulder pads, arm pads, gloves, shoes, and jerseys. Goalies are not required to wear shoulder pads or arm pads, but may choose to wear shin guards, chest protectors, and throat protectors. Optional equipment for goalies includes football pants with or without pads. Field players may wear shoulder pads and/or football helmets (as long as the face mask is replaced with a NOCSAE [National Operating Committee on Standards for Athletic Equipment] approved face mask). Mouthpieces must be brightly colored to allow for easy observation. Standardized gloves may not be altered. The helmet is designed primarily to protect from impact of the ball or stick, but not from player impact.

Increasingly, lacrosse is being played on artificial turf fields. This has led to an increase in certain injuries, since natural turf is prone to give way under forces while artificial turf stays in place. The newer synthetic turfs have a rubber base and artificial grass blades so there is more give when pushing off and cushion upon impact. These new products, called Fieldturf and Nexturf, have not had enough research to establish any improved safety data.

Box lacrosse differs from field lacrosse. This form of the game is played inside, with six members per team, in a playing area roughly the size of a hockey rink. This is a smaller field, and players use slightly different equipment. Playing time consists of three 20-minute periods, and games may end in a tie, with no sudden-victory play (unless it is a playoff game). Also, there is a 30-second shot clock, the goal is 4 ft by 4 ft, and there is no restriction on the area the players may cover (all players may move forward). Penalties are basically similar to those in field lacrosse, attempting to provide a safe playing field for all players involved.

The women’s playing field is larger than the men’s (120 × 70 yards). Women do not employ the protective equipment used by men. All players must wear mouthguards, and optional equipment includes close-fitting gloves, soft head gear, noseguards, and eyeguards. The goalie is required to wear a face mask, helmet, throat protector, and chest protector. Optional for the goalie is padding on the hands, arms, legs, shoulders, and chest.

A team has 12 players: one goalkeeper, six defenders, and five attackers. Games consist of two 30-minute halves (except with high school games, which are 50 minutes long, each half being 25 minutes). The most influential difference in injury rates between men’s and women’s lacrosse is that women’s lacrosse is noncontact. The only situation in which a check is legal is if the defending player is a step in front of her opponent, and she taps her crosse against her opponent’s crosse in an attempt to free the ball.

To succeed at lacrosse, one must have endurance, speed, agility, and strength. The games are long, and consist of almost nonstop action during playing time. Furthermore, the players need to be able to accelerate quickly and change direction instantly. Increased strength allows for harder shots, harder checks, and more resiliency against player impacts. To sum up the requirements of lacrosse, participants must have full function of all their faculties, both physical and mental.

Training regimens vary in relation to the sports season. Off-season preparatory conditioning is very different than in-season maintenance training. In the off-season, endurance is often emphasized and improved by distance running up to 25 miles per week. Plyometric training may also be used to develop endurance and enhance agility. Of all the skills needed to play goalie, agility may be the most important. Hand-eye coordination is almost as important, which it can be improved by participating in other racquet sports in the off-season, such as racquetball. To develop lower extremity agility, jumping rope and running tire courses are useful. Weight training should consist of 3 to 4 days of resistance training per week, but not so frequent that there is not ample time for recovery of muscle fibers. Areas of importance include the shoulder and lower extremities. Isotonic resistance is preferred to isometric contractions, since it permits strengthening throughout the entire range of motion. One example of an exercise to increase upper extremity strength is placing a weighted ball (i.e., a low-weight shot put) into the head of the crosse while cradling and performing running drills. Female athletes emphasize strength training less because there is less physical contact than in the male game.

Anaerobic conditioning is crucial since lacrosse involves quick bursts of power and speed. To adequately improve anaerobic performance athletes must use high-intensity-shortduration (HISD) activities in addition to highintensity-medium-duration (HIMD) activities. HISD includes sprint training at distances from roughly 50 to 400 meters, plyometrics, and interval training. HIMD involves sprint training of 100 to 800 meters using short recovery periods of 30 to 60 seconds.

Training during the season focuses on continued endurance. This is maintained and improved by frequent practices and scrimmages. Strength training should be reduced to two days per week, to allow for the recovery needed by the increased intensity of practice and scrimmages in addition to the weight exercises. Speed should be improved by using sprints and interval training.

Flexibility is the last component of conditioning and is equally important to men and women, being directly responsible for preventing or allowing certain injuries. Flexibility is a basic requirement, but it is frequently lost in an attempt to improve the previous mentioned qualities. Lower extremity flexibility is of paramount importance, and shoulder/trunk mobility is also a very important area to be addressed.