A machine marketed as the new way to achieve a full-body workout has met criticism in its claim to provide users with the benefits of a 90-minute workout in as little as four minutes.

According to the machine's Web site, hitcenters.com, High Intensity Training (HIT), a Canadian-based fitness center, claims its new workout machine can provide a healthy person with a beneficial work out in four minutes.

The machine is built similar to an elliptical machine and uses range-of-motion techniques to provide a workout, according to msnbc.com.

Range-of-motion exercises mean the body is performing single movements at a time, such as an arm or leg press. This process allows the body to focus on slow, controlled movements.

Exercise physiologist Terry Shepherd established the first HIT center in 2000 to provide fitness training to maximize the body's potential, according to the company's Web site.

It is not possible to obtain the same results in a four-minute workout as a 90-minute one, said Donna Korzick, assistant professor of physiology and kinesiology at Penn State.

The Canadian Broadcasting Corporation (CBC) Web site said the four-minute workout burns between 40 to 50 calories per session but the body will continue to burn up to 500 calories as the day progresses on. This "afterburn" effect can lastto 24 hours, the site said.

The claim that a person will burn the equivalent of 500 calories after a four-minute workout does not take into consideration a person's weight or body mass, Korzick said. "The bigger you are, the more calories you will burn. However, if you are extending this to obese individuals, they usually can't exercise for as long or as intense, and thus total caloric expenditure will depend on the total amount of work performed," she said.

Currently, there is only one HIT center offering four-minute workout technology. The center plans to open two more facilities in Toronto soon and establish 40 to 50 more locations within the next five years, the CBC Web site said.

"I would say with confidence that it is very unlikely, if not impossible, for any machine to provide the same health benefits in four minutes as a 90-minute regular cardio workout," said Margaret Spear, director of University Health Services.