Increased physical activity is extremely beneficial to counteract overweight and prevent related chronic disease, such as type 2 diabetes and its often devastating health consequences. However, many employees do not partake in physical activities offered at their worksites because these programs may be designed with a "one size fits all" approach that leaves out the most vulnerable workers. Two issues are discussed here with an eye towards making programs effective: 1) Addressing individuals' needs and preferences; and 2) taking a multilevel or systems approach. 1) In addressing individuals' needs and preferences, health promotion programs should be tailored to the specific life situations: What types of activities do employees prefer and enjoy? What support might an individual need to increase her or his physical activity? What barriers in the work situation or community might interfere with beginning physical activity? Whether these barriers are real or perceived, without knowing how to address them an individual may never manage the first steps towards becoming physically active. Studies of smoking cessation show that smokers prefer physician advice for support to quit smoking and women specifically prefer group assistance. However, there has been little comparable research on exercise preference. One study of a large group of adults found that most people preferred walking, regardless of their age. The most frequent barriers to exercise reported by people 18-39 years old were insufficient time, lack of motivation, and child care responsibility; poor health and fear of injury were bigger concerns for individuals 40 years and older. The most preferred support system for older individuals was advice from a health professional and for younger individuals was group support. This study suggests that a group walking program at lunchtime would likely meet the needs of many people, even those who are not physically active, although older people might want access to professional health advice before joining. 2) To enhance employee participation in physical activity program offered by the worksite, McLeroy and colleagues recommend an "ecological approach". In this framework, multiple levels of influence must be identified for an effective program. The ecological approach emphasizes the importance of the system (e.g., the workplace) and its characteristics and describes behavior as a dynamic interaction between an individual and the environment. Four levels of influence have been identified: 1. Intrapersonal factors: how people acquire knowledge, attitude and skills to perform certain behavior. For example, fear of injury may preclude older employee from participation in physical activity program. Advice from health professional to increase their knowledge and skill in how to perform physical activity may reduce the fear of injury and increase participation. 2. Interpersonal process: defines individual's social identity and role within the community, family or social group. For example, lack of time or need for child support could be addressed by increased staffing, encouraging team work, and providing social support. 3. Institutional factors: rules and regulation, policies at work may prevent an individual to participate in physical activity. Many employees can not participate in worksite physical activity program due to inflexible jobs and organizational mandates. This could be addressed through "buy in" from top management for program development and implementation, such as a release-time policy for all staff who wish to participate in scheduled fitness activities. 4. Community factors: community resources could play a major role to implement worksite physical activity program. For example, providing discount coupons for a gym facility or baby sitting at a local church or other organization may make physical activity more accessible for those most in need. The ecological perspective or a system approach thus provides guidelines for the practitioner to design and implement the most effective program, while addressing participants' preferences, perceived barriers and support system needs.