5 Competitors Who Inspire

Kirstie Alley, the 60-year-old former Cheers star who has famously struggled with her weight for years, has shed 100 pounds since March. Now she's encouraging others to join her in getting fit by dancing for 100 days beginning January 1.

Alley started a strict diet and exercise routine early this year in an effort to prepare for her stint as a contestant on Dancing With the Stars. Now, dancing has become central to her fitness plan. "I'm trying to start a grassroots movement and I hope you all join in," Alley tells the San Francisco Chronicle. "I'm doing a hundred days of dance, starting January 1. What you do is you join in, and whether you dance for 30 minutes or an hour, you dance for 100 consecutive days. I want everybody in the world to join in on this; it's a fun way to stay fit."

Alley isn't the only one inspiring us to get into shape this holiday season. Here are four others who have overcome obstacles to accomplish impressive athletic feats.

1. Teresa Brynes: To celebrate her 45th birthday, Brynes completed the Ironman Arizona on Nov. 20 to raise funds for breast cancer. In June 2009, three days before she was to compete in the Eagleman 70.3 Triathlon, she was diagnosed with Stage III breast cancer at 42. After a double mastectomy, chemotherapy and radiation, Brynes is now cancer-free. "Cancer has changed my whole life, including my attitude towards racing triathlons," Brynes writes on her fundraising page. For this race, she raised $5,000 for the MaccaNow Foundation, an organization started by professional triathlete and two-time Ironman World Champion Chris McCormack, whose mother died of breast cancer.  

2. Marine Captain John O'Brien: Seventeen years ago, O'Brien, now 45 and retired, was severely injured in the line of duty. As a result, he lost his left leg just below the knee and his left arm just above the elbow. While O'Brien had always been an avid runner and a fitness enthusiast, he says exercising became a struggle due to prosthetic limitations and mobility and safety issues.

After losing 33 pounds, O'Brien decided to celebrate by training for the Marine Corps Marathon in Washington, D.C. With prosthetics, he completed the 2010 marathon in under five hours. This year, he did it again, beating his time and raising more than $10,000 for Toys for Tots in the process.

3. Andrew Johnston: Turning 40 next month, Johnston was a professional cyclist and triathlete until he was diagnosed with chronic myelogenous leukemia in 2004 -- but that hasn't stopped him from competing.He's now busy preparing for next year's Ironman World Championships in Hawaii. He's undergoing a rigorous daily training program including swimming, cycling, running and weights. "After four years away from competition and the oral chemo I take daily, it's not going to be easy," Johnston says. "But Ironmans never are."

4. Josh Philbeck: Last month, the 37-year-old from Broken Arrow, Okla., represented the Missouri Valley section at the U.S. Tennis Association's (USTA) League National Championships in Tucson, Ariz. Born with Holt-Oram Syndrome, which is characterized by skeletal abnormalities of the hands and arms, Philbeck has no forearms and only eight fingers. Along with his teammates from the Indian Springs Country Club, Philbeck worked hard to make it to Nationals.

"I had to learn how to [maneuver] a lot on my own, and I have an unusual grip on both golf clubs and tennis racquets," Philbeck told the USTA. "But it hasn't stopped me from being able to compete." Philbeck also works to help others with similar conditions. Two years ago, he started The Wizard's Way, an organization that helps children with Holt-Oram Syndrome. The company sells golf and inspirational DVDs that teach golf fundamentals, as well as teaching children to conquer the difficulties in their lives.

Read more: 5 Athletes Who Inspire This Summer