Alan Horton, 28, Marathoner
Key Tip: Stubbornness is not a bad thing. Sometimes you have to miss that social event or activity. But that's why there's downtime. Make the most of it.
Kyle Daniels, 33, Paddleboarder
Key Tip: Make your car your base camp. I keep a paddleboard, running shoes, and something to swim in inside my car at all times. That way I never have to miss a workout.
Kathleen Calkins, 33, Triathlete
Key Tip: Commit to an event, whether it's a 5K or a marathon. It doesn't have to be extreme. It's all about having fun, and feeling good about yourself. But you need a plan or it's not going to happen.
Kimo Seymour, 40, Mountain Biker
Key Tip: Make sure your goals are actually achievable. Don't set a goal so high you destroy your life to attain it. Set goals you can achieve with substance.
David Goggins, 34, Endurance Warrior
Key Tip: Stop making excuses. If you want to make something happen, just make it happen.
After fellow commandos were killed in action in Afghanistan in 2005, Gogginsa Navy SEAL temporarily working a desk jobdecided to pay tribute by setting the hardest goal he could think of: running the 135-mile Badwater Ultramarathon.
Next fall, before he's redeployed into combat zones, Goggins plans to climb Everest.