Baseball is one of the few sports in which spectators can have a physical influence on the outcome of the game. Because this potential exists, Major League Baseball created rules to govern any situation involving fan interference in a game.

Football players wear gloves for a variety of reasons. They include improving performance, keeping the players' hands warm and preventing injury. Most football gloves come with a size ranging from small to extra-large, but to determine what size you wear can be a little tricky.

Throwing the ball is one of the most fundamental skills in football. Quarterbacks like to throw the ball farther so they can stretch the defense and complete long passes, which can help create a variety of options for the offense. To throw the football farther, quarterbacks must work to increase their arm strength.

Modern running shoes are feats of design. As the single most important piece of equipment a runner needs, shoes have to provide support, flexibility, grip and stability.

Although the phrase "there is no I in team" is often overused, it resonates strongly when you talk about volleyball squads. University of Northern Iowa volleyball coach Bobbi Petersen, in an article in the "Waterloo Cedar Falls Courier," said, "Volleyball is one of the most team sports there is.

Chafing occurs with friction against the skin and causes uncomfortable irritation on the skin. A triathlon increases the risk of chafing because of the sweat and moisture generated during the race. The biking portion of the race leaves you exposed to chafing where the bike saddle rubs against your legs.

Competitive swimming can start as young as 4 years of age in many recreational leagues. It typically ends at age 18, when swimmers are eligible for masters programs and college teams.

Knuckle pain can be especially detrimental to a boxer's success. A professional fighter earns a living with his fists. When his hands are injured, he may be out of business. Hand injuries are normal for a boxer. However, knuckle pain is often caused by simple mistakes unseasoned fighters make during training.

Weight training is a key component to baseball player development. Players at the higher end of the sport train year-round to build and maintain their sport-specific strength. But players must carefully manage their weightlifting regimen during the season.

Football players, depending on their position, may be both muscular and also lean, fast and agile. The sport is very physical and features intense contact on every play.

Many school-aged children across the country try out for soccer each year. Soccer tryouts can be highly competitive, especially for travel teams, and knowing what to expect can give your child an advantage. Soccer coaches look for speed, agility, accuracy and team spirit when choosing young athletes.

Nose plugs most often are seen worn by synchronized swimmers. Synchronized swimmers do complicated twists and turns in the water, which could lead to uncomfortable water in the nose if they aren't constantly carefully.