You already know that it doesn't matter what you wear to play a pickup game of soccer and that some form of the game can be played just about anywhere. Playing on an official team is a different matter. Rules governing clothing vary depending on the type of soccer league and where it's located.

Whether you play ball in high school, college, the Babe Ruth League or the major leagues, you’ll cover the same distance when you make a trip around the bases. All regulation infields conform to the same measurements at that level of play, but you’ll find differences in the outfields.

High school soccer teams typically use 11 players, but must have substitutes available when players are injured, receive warnings or need a rest. But this isn't hockey, where a coach can sub players on the fly. Coaches have to follow substitution rules set by the National Federation of State High School Associations.

A set is a quick motion that positions the volleyball for a hit. The ease with which setters put the ball up in the air is deceiving. Setting a volleyball correctly is the most difficult skill to learn in volleyball.

The rules of basketball make it pretty clear that you can't touch the ball while any part of you is out of bounds. The rules are different if a player steps out without the ball. Players who go out of bounds can legally rejoin the play and touch the ball once they have both feet back on the court.

Swimming jockstraps serve two purposes, whether you're at the pool or the beach. The support helps prevent injuries while the coverage helps prevent embarrassment. Swimming jockstraps are available at sports and underwear retailers.

Joint swelling occurs typically after an injury to ligaments, and is a way for your body to protect your joint. Ankle sprains that lead to swelling are fairly common sports injuries. Once care has been given -- rest, ice, compression and elevation -- rehabilitation can begin.

Bicycling is not only a popular, enjoyable activity, it's also a full-body workout, utilizing nearly all of the major muscle groups in your body. Although it primarily relies on the muscles in your lower body, your upper body also gets a workout.

A baseball glove is one of the most important pieces of equipment you can purchase for a Little League player. Youth baseball gloves are often made of synthetic materials and can be broken in quickly. They are designed with smaller fingers and wrist openings to help best fit small players.

Football plays are not designed to be easily read -- if you can read them in the stands or in front of the TV, so can the defense. Teams that provide obvious clues to their plays end up struggling for yardage, and the offensive coordinator’s job ends up on the line.

The key phrase to remember when guarding a bigger player in basketball is "ball-you-man," which means you must keep yourself between your opponent and the ball, wherever it is on the court.

The balance beam is one of four main apparatuses that are used in competitive women’s artistic gymnastics. The beam itself measures 16 feet long and 4 inches wide. Early balance beam routines consisted of dance-based moves, including leaps, poses and acrobatic skills like walkovers and back handsprings.