Ab-solutely false. (updates).(fitness devices tested)(Brief Article)

Claims by some companies advertising fitness devices that promise toned abs are misleading, says Peter Francis, PhD, director of the biomechanics lab at San Diego State University. Francis tested a number of fitness products--electrical stimulators and workout machines--advertised on late-night television infomercials and concluded that most of the devices simply do not work.

"If you're not burning as many calories as you're taking in, you won't change the appearance of the fat tissues surrounding your abdominal muscles," he says.

In his research, Francis measured the electrical response of abdominal muscles on 31 test subjects using a process called electromyography, which yields a printout of peaks and valleys similar to what polygraph--lie detector--machines produce. Electrodes placed on 16 women and 15 men, ages 19 to 40, picked up electrical impulses coming from muscles as the subjects ran through 10 repetitions of exercises. "The bigger the signal, the more tension in the muscle," says Francis, whose research on abdominal exercises was still unpublished and under review at the time of this writing.

After being shown the proper technique for each exercise, participants took turns using the assorted fitness devices while performing a variety of crunches and curls. The abdominal crunch--performed in a supine ...