"... a person's health-related behavior depends on the person's perception of four critical areas: the severity of a potential illness, the person's susceptibility to that illness, the benefits of taking a preventive action, and the barriers to taking that action. The model also incorporates cues to action (e.g., leaving a written reminder to oneself to walk) as important elements in eliciting or maintaining patterns of behavior. The construct of self-efficacy, or a person's confidence in his or her ability to successfully perform an action... has been added to the model, perhaps allowing it to better account for habitual behaviors, such as a physically active lifestyle." -http://www.csupomona.edu/~jvgrizzell/best_practices/bctheory.html
So what this means is that if its not important to a person, or if they don't think they can accomplish it, they won't do it. Seems like common sense. By making it a habit, it becomes bonded into our daily regime. Some things are so engrained in us at an early age that its nearly impossible to break. For example- brushing our teeth. Our society has established that as young kids, we brush our teeth and it turns into a twice daily part of life. If fitness is developed into such a habit that it feels wrong to not have it in our life that day, then the battle is won without it even being a battle.
Ways to make it a Habit-
*Write it on the calendar in a public highly visible place "g" or amount of calories burned.
*Go at the same time of day on alternating days/daily
*keep a fully stocked gym bag in the car/by the door
*Have a workout buddy or hire a trainer- you are 50/50 going to go on your own, and 99% going to go if you PAID someone to meet you there. and it offers guidance
*make fitness your coping mechanism- many times people grab a drink, etc to cool off, go for a run/workout instead
*reward yourself for accomplishing a set amount of gym attendance per week
KEEP IT FUN!
Good Luck and Happy Workouts :)