Aerobics is a form of exercise done to improve flexibility, muscular strength, and cardio-vascular fitness. The word aerobics means "using oxygen."

Aerobics is a method of exercise designed to maximize the consumption of oxygen by the body. In order to achieve this, a variety of stretching and strength training routines are performed to music, and led by an instructor.

To improve one's flexibility, strength, endurance and general health.

Most aerobics programs follow a general framework, which is: a warming up period, a minimum of 20 minutes of intensive exercise, and a cooling down period. Other basic rules include wearing rubber-soled shoes, and listening to the commands of the instructor.

Aerobics was developed in the 1960's by a pair of United States Air Force doctors, as a result of their research on why some muscular people were prone to poor performances in running, biking and swimming. Their findings were published in Aerobics, an extremely popular book that introduced the methods to a worldwide audience. Since then, many different disciplines have been created based on the basic techniques of aerobics. Today, aerobics is taught and practiced in many countries around the world, and has greatly contributed to the health and well being of millions.

Sneakers
(the following equipment is optional, depending on the type of aerobics program)
Exercise Mat
Hand Weights
Step Board

Stretching and staying properly hydrated can help avoid most aerobics related injuries.

Participating in aerobics requires no training, beyond having a basic level of fitness. Usually programs are divided into beginner, intermediate and advanced based on skill level of participants and results desired.

Curl - bending an arm or leg back towards the body

Pull - moving the arms back towards the body, as if pulling an object

Step - a rhythmic movement of the legs and feet

http://en.wikipedia.org/wiki/Aerobic_exercise
http://k2.kirtland.cc.mi.us/~balbachl/step.htm