Rebound exercise
Rebound exercise (or “rebounding”) is a type of elastically leveraged low-impact exercise usually performed on a device known as a "rebounder"—sometimes called a "mini-trampoline"—which is directly descended from regular sports or athletic trampolines. Some of the basic movements and actions of rebound exercise include bouncing in place (sometimes also called "jumping" or the Basic Bounce), jumping jacks, twists, side-to-side motions, running in place, dance movements, and a wide variety of other movements, patterned or un-patterned, with or without the use of hand-weights or other accessories. A wide variety of physical and other  benefits are claimed for rebound exercise, which experienced a tremendous upsurge of interest in the mid-1980s. A rebound exercise program can focus on aerobics, strength, or just simple easy non-jarring movement, depending on the needs of the person bouncing. Typically round, rebounders are much smaller (at about 3 to 4 feet in total diameter) than regular trampolines, and they are not designed for stunts. Other equipment for one or two feet, such as jumpers of Aerower and Kangoo Jumps or BOSU balls, can provide a type of rebound exercise experience, and regular, full-size, sports or athletic trampolines can  also be used to perform the various movements, routines, programs, and styles that characterize rebound exercise. Rebounders are predominantly used solo in personal homes, but are also found in some health clubs, and physical rehabilitation centers. History. The modern trampoline was created by George Nissen in Cedar Rapids, Iowa, in 1936. In 1938 the first “small trampoline” was created by Ed Russell, who left his ideas and prototype with Victor Green, who patented the “small trampoline” in 1975. Within a year, five American companies were manufacturing small trampolines, which were soon called rebounders. In part because of business promotional efforts , and in part because of a number of scientific studies that seemed to support the value of rebounding (see “Scientific Studies” below), from 1981 to 1984 rebound exercise became very popular in the United States, with reportedly over one million units selling a year. The fad faded by the end of 1984, supposedly because poor quality foreign-made units had flooded the U.S. market. Today, there appears to be an upsurge of interest in rebound exercise, in part due to increasing quality of equipment and in part due to its use in physical therapy and the fight against obesity generally . Rebound exercise is especially popular in holistic health circles, as rebounding is said to combat a number of ailments (see “Claimed Benefits” below) given its ability to generally and gently stimulate the immune system and provide aerobic exercise without jarring the physical structures of the body as the elastic element of the rebounder is said to take up to 85% of the shock that the body would otherwise experience. Equipment. Rebounders are often called “mini-trampolines,” but this is a misnomer. Trampolines are generally much larger, and are designed to perform stunts such as flips and seat drops, while it  is dangerous to perform stunts on rebounders. While there are “double mini-trampolines” used in sports and even Olympic competition, these are designed specifically to perform stunts and are used in a substantially different manner than is the typical rebounder. Most but not all rebounders are round, and consist of the following parts: Since their introduction, many improvements have been made to the quality and construction of rebounders. Spring size, shape, and durability have improved greatly over time, and in the last several years springs have been replaced entirely in certain high-end units by bungee-bands, which are quieter  and may also offer certain advantages in terms of smoothness and user experience. Units with folding legs, and units whose entire body (including the mat and the rim) folds in half, or even in quarters, have been introduced. Rebounders can be purchased for anywhere from between $40 and $1,000 and up. The largest two differences between rebounders, other than manufacturing materials, relate to the source of elasticity. As this mechanism is responsible for carrying the weight of the user, their longevity and responsiveness directly affect the rebounding experience. The two main mechanisms currently in production are bungee cords  and piano wire. Types of exercise and movements performed. Rebound exercise begins as soon as someone steps on a rebounder and begins to move their body. It can be highly aerobic — full-on sprints and interval training are ideal on a rebounder, because it does not jar the physical body anywhere near as much as does hard ground — or it can be very slow and gentle, with only a gentle rocking taking place. Just as rebounders have evolved from poorly made spring-based units to modern spring-based units and high-end bungee-based units, the types of exercise and  movement done on rebounders has evolved as well. Al Carter initially introduced the distinction between the “health bounce” (a gentle rocking motion that anyone in any state of health can do, which was said to stimulate the immune system), an “aerobic bounce” that involved elevating the heart rate (either running in place or dancing), and the “strength bounce,” which involved higher bouncing with both feet leaving the mat (leading to both abdominal and lower body strength directly as well as to the strengthening of all bodily cells through the accelerative force applied (see Claimed Benefits below). Subsequently, many different approaches  have been taken to rebounding. For example, collaborating with Al Carter and working with athletes in the late 1970s and 1980s, Dr. Harry Sneider, a college athletic coach, brought his sport-specific training methods and the use of resistive hand-weights to rebound exercise. More recently, JB Burns has pioneered an infomercial and mass equipment approach making use of dance-style workout DVDs for home users. Along the way, a variety of celebrities have endorsed rebounding, including the fitness guru Jack LaLane and the self-help guru Tony Robbins. Bob Hope reportedly said, ““I keep my REBOUNDER at the foot  of my bed, and use it daily,” and President Ronald Reagan reportedly said, “If you see somebody jumping up and down on the second floor of the White House, that's me rebounding." Claimed benefits. There are five main organizing themes or perspectives with respect to what is claimed [doubtful source: trampoline sales site] to be special about the health and fitness benefits of rebound exercise: Rebounding is said to assist dozens of specific medical conditions—from arthritis to vision improvement—but there is little systematic peer-reviewed scientific evidence for these claims. NASA study and scientific support generally. The  single most important and most frequently quoted scientific research study on trampolining was conducted in 1980 through NASA by A. Bhattacharya, E.P. McCutcheon, E.Shvartz, and J.E. Greenleaf; Biomechanical Research Division, NASA-Ames Research Center, Moffett Field, California, in cooperation with the Wenner-Gren Research laboratory, University of Kentucky, Lexington, Kentucky. The key findings for this study include the following: The NASA study used a "regulation trampoline bed (American Athletic Equipment)...2.74 x 4.56 m and made of nylon webbing supported by springs." The study used a competition-style trampoline, size in feet: 9'x15'. "Each phase of the sequence included a  2-min warm-up, followed by 5 min of jumping. The four heights, measured by the distance the subjects’ feet were elevated above the trampoline bed, were 18, 37, 75, and 100 cm. A 5- to 10-min rest period was provided between each jumping level." The jump heights in inches were: 7", 14.6", 29.5" and 39.4". The NASA study did not involve a rebounder or mini-trampoline. </ref> There is no evidence that NASA ever stated 'Rebound exercise is "The most efficient, effective form of exercise yet devised by man."'