It always happened half-way through her regular, eight-mile run. At the fourth mile, the 50-year-old female distance runner experienced a complete emptying of her bladder without warning," recalls Barbara Woolner, a registered nurse and continence care specialist from La Palma, California. "This never happened to her at any other time, but apparently her muscles fatigued during her run" so that she voided.

Although the woman's doctor suggested surgery, Woolner was able to use biofeedback to teach the runner exercises that strengthened her pelvic floor muscles. "Eventually she was able to run dry," says Woolner, whose address was listed in a brief article about incontinence in Runner's World magazine. "I got a couple hundred letters from women aged 15 to 61, most of which said, 'I thought no one else had this problem.' The typical letter was full of frustration, helplessness and embarrassment, plus delight that someone finally talked about the problem."

Over the last few years, the common, but little-discussed problem of urinary incontinence has increasingly come out of the closet. But while many people are now aware that the involuntary loss of urine affects a large proportion of older Americans -- some 40 percent of women and 20 percent of men over age 60 -- few realize it is also a significant problem for female exercisers of all ages.

One study of female colleges athletes between the ages of 18 and 21 showed that "28 percent experienced urine loss at some point when doing their sport," reports Ingrid Nygaard, assistant professor of obstetrics and gynecology at the University of Iowa. Her earlier study of 290 female exercisers ages 17 to 68 showed that one in three experienced incontinence during exercise, 20 percent stopped exercising because of the problem, 18 percent changed the way a specific exercise was done and 55 percent wore a pad during exercise.