Paula Radcliffe

Two elite runners were absent from recent marthons. We knew Kara Goucher was skipping the Boston Marathon in hopes of getting pregnant (but hadn't heard word before that big race) and then mommy marathoner Paula Radcliffe skipped her hometown marathon after announcing she was pregnant with her second child.

We have since learned that these two Nike-sponsored athletes have been training together, and that both marathoners have known since January that they're pregnant. Kara Goucher announced, right before Mother's Day, that she's expecting a baby boy with a due date of Sept. 29, which she coincidentally shares with Radcliffe. The two marathoners have been training together in Portland, OR, near Nike headquarters and have forged a friendship. Although Radcliffe told the New York Times that she doesn't see herself as a "mommy mentor," she has offered Kara some sound advice; namely to listen to her body and stop when she feels a twinge, and to forgo timing hill repeats.

These two are fierce competitors and both are aiming to run (and win the gold) at the London Olympics in 2012. But these two runners have forged a sweet friendship while logging mileage side by side. Radcliffe said, "When both of us stand on the start line and the gun goes off, we both want to win that race. But there’s room for a really good friendship at the same time."

Congrats to both Kara and Paula. I wonder who will reach the delivery finish line first?

Although she has won the race three times, favorite Paula Radcliffe placed fourth in the New York Marathon. The first woman to cross the finish line was Derartu Tulu — the first Ethiopian woman to claim first place in the NYC Marathon in its 40-year history.

Tulu ran the course in two hours, 28 minutes, 52 seconds and was there to comfort Radcliffe as the world record holder limped across the finish line, holding her knee and crying in agony. Second place went to Russia's Ludmila Petrova , who ran the course in two hours and 29 minutes flat. Christelle Daunay, of France, came in third (2:29:16), nine seconds ahead of Radcliffe.

Tulu, who gave birth to her second daughter in 2006 and increased her brood by adopting four orphans, wasn't ready to quit racing. With two Olympic gold medals under her belt and a previous marathon win in London in 2001, Deratu ran with a calm confidence and proved that returning to the sport was well worth it.

For details on the men's race, read more

Over training happens. You love what you do. You do it too much. Your body starts to break down. Your bones begin to crack. An over use injury you definitely want to avoid is a stress fracture.

Common in professional sports that intensely work the lower body like running and basketball — hoops star Yao Ming has been suffering from one in his foot for two years now and marathoner Paula Radcliffe has battled one in her femur.

A fracture, aka broken bone, is caused by a sudden trauma like a fall. A stress fracture occurs when a bone can't hold up against repeated stress overtime. Cells known as osteoblasts make bones and attempt to keep the bone strong and rebuild them while under strain, while osteoclasts are cells that remove damaged bone tissue. The repeated stress weakens the bones, and ultimately the osteoclast cells win creating a microscopic fracture on the surface of the bone. This small crack can create lots of pain. X-rays usually cannot detect the fracture, but an MRI or bone scan if deemed necessary can diagnose a stress fracture. Often a stress fracture can be diagnosed based on your history, since over use injuries often run a specific course.

Learn how to avoid a stress fracture.