The document discusses the transtheoretical model of behavior change, which includes 5 stages of change: 1) Precontemplation, where a person is unaware of the need to change. 2) Contemplation, where a person acknowledges the problem but has not taken action. 3) Preparation, where a person plans to take action. 4) Action, where a person actively modifies their behavior. 5) Maintenance, where a person works to maintain the behavior change long-term. The document then discusses common barriers to adopting an active lifestyle and provides suggestions to overcome each barrier.