In her work as a certified lymphedema specialist, Kim Schminkey had helped scores of breast cancer survivors manage the painful, frustrating side effect of breast cancer surgery.

At 36, the Wyoming, Minn., mother of two developed it herself in the months following a double mastectomy.

"It was hot and I felt the tightness and I thought, 'Oh no, here we go,' " she said. "Not this, too."

Lymphedema strikes as many as 40 percent of breast cancer survivors and represents a lifetime risk for almost all of them. Lymph node removal, routine in breast cancer surgery, disrupts the lymphatic system, which can lead to a buildup of fluid in the arm and shoulder. The National Cancer Institute has termed lymphedema "one of the most poorly understood, relatively underestimated and least researched complications of cancer."

Prevailing wisdom long held that use of your arms — from swinging a tennis racquet to lifting a bag of groceries — after surgery and especially radiation, could trigger the chronic condition.

Emerging research is challenging that idea. So much so that a new generation of breast cancer survivors is embracing physical activity with greater confidence.

Kim Schminkey, left, and Dr. Sandra Rosenberg paddle with other breast cancer survivors who have suffered lymphedema.

"For years, there was one-size-fits-all advice for patients: Don't, don't, don't," said Dr. Sandra Rosenberg, a St. Paul rehabilitation physician. A 21-year breast cancer survivor, Rosenberg treats lymphedema patients and has lived with the condition herself since her double mastectomy at age 34.

"There was no data to show exercise was a problem," she said. "What women were told was based on myth, not science. We now know that women can exercise — and exercise a lot — if they do it properly."

Last month, about a dozen physical therapists and fitness professionals from around the region attended a first-of-its-kind workshop to learn how to supervise strength training for breast cancer survivors. The training is based on clinical trials from the University of Pennsylvania that showed strength training did not cause lymphedema in women who were at risk for it. The trials also demonstrated that women with lymphedema who exercised had fewer symptoms than the control group.

The workshop was taught by Cathy Bryan, one of the authors of a landmark study based on those trials. Bryan's 2009 study was published in both the Journal of the American Medical Association and the New England Journal of Medicine.

"This is a game changer. We demonstrated that weight training can be safe," said Bryan. "It should be slow and progressive and overseen by a clinician trained in the biomechanics of exercise."

Enter the dragon

Another body of research, conducted earlier, found that strenuous upper-body exercise is also safe.

In 1996, a Canadian sports medicine doctor trained a team of breast cancer survivors to race in 40-foot-long dragon boats, exactly the sort of activity that had been considered taboo. His research found that participants improved their physical and mental health without increasing their incidence of lymphedema.

In response to those findings, scores of dragon boat paddling teams made up of breast cancer survivors have sprung up around the country, including a highly competitive team based in the east metro. That team, the Dragon Divas, will paddle in an international dragon boat competition in Sarasota, Fla., at the end of the month.

Rosenberg is a medical adviser for the Dragon Divas — and she's also on the team.

"It's hard work, and it feels good," she said of paddling. "There's no reason we should miss out on the benefit of physical activity."

On a recent practice on Lake Gervais in Little Canada, two of the Dragon Divas wore fitness monitors that showed they burned 600 to 700 calories in a two-hour practice.

While Rosenberg, along with many other doctors, now encourages breast cancer survivors to exercise, she does so with a caution.

"You don't start at this level, you work up to it," she said. "If you push yourself too hard, you pay for it. If the arm starts to get heavy or achy, back off.

"Sure, we have Divas with lymphedema," she added. "Some get better — and no one gets worse."

Kevyn Burger is a freelance writer and a newscaster at BringMeTheNews.com.