Michela Larsen has stuck with her exercise plan -- two strength-training sessions, a yoga class, and three to five walks a week -- like batter to a mixing bowl for almost two years now. She's tenacious, despite a hectic life that includes raising two sons and running two busy Boston-area restaurants with her partners. But Larsen's fitness streak only hints at her perseverance -- she has tinkered for nine years to find the right routine.

Being consistent is no easy feat, but the key, say many experts, has as much -- or more -- to do with your mind as your body. And the name of the game is willpower. "Whether you're an NBA player or a casual runner, it's all about attitude," says Greg Shelley, Ph.D., a sports psychologist and professor at Ithaca College in Ithaca, New York. The can-do spirit that propels you out of your bed and to the gym or your walking route, day in and day out, isn't something that you either have or you don't, like blue eyes or flat feet. It can be built, just like your sculptured biceps. Here's how.

• Revisit your vision. It doesn't take a lot for the hustle of everyday life to distract you from your good intentions. So before you slide out of bed each day, think about two or three things that you'll do that day to relate to your exercise goals, such as meeting a friend for a walk, or recalling a good feeling you had while working out the day before.
• Focus on what you can change. Just like a basketball player at the free-throw line learns to block a chanting crowd, you must also develop the power to overcome obstacles. For instance, you can't stop snow and ice, but you can join a gym in the winter months.
• Be your own yardstick. You just did two pull-ups. Are you elated because you only did one last week, or discouraged because the woman next to you just cranked out five? Staying focused on your own progress reinforces positive feelings that are keys to your success.
• To thine own self be true. Choose activities, places, and situations because you like them, not because you think you should.
• Share the highlights. Tell your spouse about your amazing hike. Or bring him along. Both exercising together and talking about it will enhance your enjoyment and reinforce your commitment.
• Track your progress. Take five minutes each evening to record the best moments of your day -- the things that made you feel best -- in a notebook. Chances are, you'll find yourself dwelling less on the negative, and more on the positive. You'll also be more motivated to stick with your program.
• Tune into the process of exercise. If you want to do something over a lifetime, you have to find joy or a sense of accomplishment within the activity itself. Pinpoint those feel-good moments -- zooming down a big hill, paddling in perfect rhythm, easing into your favorite yoga position. Soak them up. Recall them later. You'll be better off for it.