Step aerobics, also known as bench aerobics and step training, is a form of aerobic exercise that involves stepping on and off a small platform. Step aerobics was studied by physiologists in the 1980s, and in 1990 it swiftly grew in popularity in the U.S. as a style of health club exercise, largely because of promotion by Reebok of the Step Reebok device and associated exercise routines, prominently advocated by Gin Miller. Step aerobics attracted more men to group exercise classes. At its peak in 1995, there were 11.4 million people doing step aerobics. Today, step aerobics classes are carried by many health clubs. Exercise routines include weights held in the hands for upper body development. Music with a medium (not fast) tempo often accompanies the routine, and learning a choreography sequence can hold the participants' interest. History Background Aerobics traces its origin to the 1968 book Aerobics by Dr. Kenneth H. Cooper, which inspired Jacki Sorensen to start her Aerobic Dancing program, combining music and dance routines to create an aerobic exercise pattern. Also in 1969, Judi Missett developed Jazzercise, combining jazz dance with fun exercise in much the same way. Building through the 1970s, Missett's Jazzercise and Sorensen's Aerobic Dancing became very popular in the U.S., such that by 1981–82 they counted 4,000 instructors each, and more than 300,000 students combined. In 1982, Jane Fonda's Workout video changed the fitness world dramatically, starting a boom in home video exercise instruction through the 1980s and beyond. This same boom benefited health clubs by increasing the number of people who were involved in fitness. Step development Stair climbing exercise was already thousands of years old when physiologists started studying its medical characteristics in the 20th century. Climbing stairs was long known to be healthy exercise for the heart. The act of stepping up and down on one bench was studied in 1986 by a team led by Doctor Fredric L. Goss of the Human Energy Research Laboratory at the University of Pittsburgh. Goss et al examined the popular HeavyHands hand weights fitness product combined with stepping exercises on the "Superstep" 12-inch (30.5 cm) fitness bench, comparing this combination to treadmill exercises and finding them equivalent. Goss followed this in 1988 with an evaluation of the energy expenditure of step aerobics combined with hand weights. At the same time, Atlanta-based aerobics competitor Gin Miller was sidelined from high-impact activities in 1986