According to the United States Census Bureau (2004), nearly 36 million people are at least 65 years of age. Furthermore, this number of aging Americans continues to grow. The leading edge of the "baby boomer" cohort turned 60 in 2006; by 2030, about one in five Americans will be aged 65 or over

as the baby boomers transition into older adulthood (Himes, 2001). This change in age demographics makes it essential for us to understand the unique gerontological health risks and concerns that exist for this aging population. Associated with these risks are health-related expenses, which are high and continue to escalate. Putting aside the staggering societal cost of Medicare and Medicaid--much of which is directed toward seniors--individuals ages 65 to 69 years old spent $5,864 in 2004, those 75 to 79 spent $9,414, and those over the age of 85 spent $16,564 on out-of-pocket health care per year (Federal Interagency Forum on Aging-Related Statistics, 2004). When facing expenses such as these, older adults would do well to look for ways in which to curb healthcare spending.

One potential solution to the rising healthcare costs for the aging population may come from increasing physical activity levels. Research suggests that physical activity participation has great potential to help decrease healthcare spending by improving overall health (Pate et al., 1995). For some age-related health risks, such as osteoporosis and cardiovascular disease, physical activity provides a proven, non-drug intervention that improves health (Blair et al., 1995; Gregg, Pereira, & Casperson, 2000). Yet, previous studies have determined that older adults tend to drop out of physical activity programs (e.g., Dishman & Sallis, 1994).

This article provides a practical, comprehensive overview of the critical yet often overlooked relationship between aging and physical activity. The article will first review the types of physical activity that have worked in previous research (from both a physiological and adherence standpoint) and subsequently offer some tools with which individuals can improve existing programs or develop successful new ones. This should assist older adults as well as practitioners interested in working with them to create programs that are motivating and fun, and, most important, that lead to improvements in physical health and mental well-being.

The Benefits of Exercise for Healthy Aging

Why should older adults participate in physical activity? It has been well documented that regular physical activity participation is associated with positive physical and psychological health (Bauman, 2004; McAuley & Rudolph, 1995; Pate et al., 1995). Epidemiological studies have demonstrated a decrease in a number of causes of mortality and morbidity for those adults who participated in regular physical activity (Blair et al., 1995). In addition, physical activity has helped counteract certain health effects of obesity in a middle-aged adult population (He & Baker, 2004), and it has the potential of reversing some of the age-related changes that occur in the cardiovascular system--hypokinetic and otherwise. Evidence suggests that exercise can positively influence other diseases that may affect adults as they age, such as cancer (Lee & Paffenbarger, 1994; Schmitz et al., 2005) and osteoporosis (Gregg, Pereira, & Casperson, 2000). Overall, the research findings strongly suggest that physical activity can have a positive effect on multiple physiological disease processes that become more common with age.

In addition to physical benefits, the degree of physical activity has been linked with mental health status in older adults. Several studies have reported lower anxiety scores in older adults who exercise regularly (Emery, 1994; King, Rejeski, & Buchner, 1998; McAuley & Rudolph, 1995). Additionally, a review of the literature on exercise and depression in older adults reveals that exercise decreases symptoms of depression (i.e., insomnia, fatigue, loss of energy, lack of concentration) in healthy older adults and depressed older adults (Barbour & Blumenthal, 2005). The literature also supports a positive relationship between physical activity and both quality of life (Rejeski & Mihalko, 2001) and cognitive functioning (Vance, Wadley, Ball, Roenker, & Rizzo, 2005). Looking at these results, older adults should feel confident that they will receive a multitude of health benefits from physical activity. Yet few older adults engage in structured physical activity programs, and those who do tend to drop out in high numbers. Why is this the case, and where have practitioners gone wrong?

Guideline-based Interventions

Historically, physical activity guidelines have recommended exercise at a set intensity (e.g., reaching a percentage of maximum heart rate or V[O.sub.2] max) for a specified, continuous length of time by participating in traditional activities such as aerobics, biking, jogging, and swimming (American College of Sports Medicine, 1975). These guidelines were designed for a young, healthy population and were very specific--almost to a fault. As a result, many people were unable to follow the guidelines if they could not exercise vigorously or if they preferred a less traditional form of activity (Sallis et al., 1989). Other barriers such as the lack of resources or a preexisting injury made it difficult for people, especially older adults, to adhere to the guidelines. Not having previous exercise experience or familiarity with a given activity may also pose a barrier for older adults attempting a new skill (Sallis et al., 1989).

Within the past decade, some of the recommendations have changed, making them easier for older adults to follow. The Surgeon General's report (U.S. Department of Health and Human Services, 1996) suggested that positive health benefits can be achieved with moderate levels of physical activity (as opposed to vigorous exercise). A simple, daily, time recommendation (30 minutes) of continuous or intermittent moderate physical activity has also been offered (Pate et al., 1995). In addition to the guidelines for physical activity for adults, the American College of Sports Medicine (ACSM) has developed a set of physical activity and exercise guidelines specifically designed for older adults (ACSM, 1998). These guidelines emphasize the importance of strength training, balance, and flexibility in the aging population, as well as moderate levels of regular physical activity (ASCM, 1998).

Based on these guidelines, practitioners have had mixed success in designing a variety of interventions for the older adult population. Interventions have incorporated a number of methods, including health education, behavior modification, and home- and group-based techniques (Conn, Valentine, & Cooper, 2002; King et al., 1998; van der Bij, Laurant, & Winsing, 2002). These interventions have differed in their content and in the relative emphasis on aerobic, strength, and flexibility training components (Hughes et al., 2005). Based on several reviews, the results that these interventions have produced are not so good. Adherence rates have been high in the short term, but no long-term effectiveness of interventions has been demonstrated in older adults (Taylor et al., 2004; van der Bij et al., 2002). In order to design an effective intervention program, it would be prudent to examine some of the barriers and determinants specific to the aging population.

Specific Barriers and Determinants

A variety of factors influence the lack of participation in physical activity. Among these are low self-efficacy, unsuitable neighborhood environment, bad weather, lower education, lack of social support, older age, low income, lack of transportation, poor body image, and health problems, such as shortness of breath and injuries (Crombie et al., 2004; Dishman & Sallis, 1994; Lim & Taylor, 2004; Reynolds, 2001). While this article cannot address strategies for reducing all of the barriers, it is important for practitioners to consider what they can do to address these barriers when designing interventions. For example, some older adults may not participate in physical activity because they do not understand the associated benefits or are not aware of the current guidelines (Reynolds, 2001). They may be less likely to attempt activity because they believe the benefits are only derived from extremely taxing activities. Some other older adults may fear injuring themselves as a result of vigorous activity and therefore avoid activity altogether. Education on appropriate intensities and activity guidelines may help to alleviate the fear of injury and improve attitudes toward exercise. This improved attitude could also have an effect on exercise maintenance, since high initial motivation, a positive attitude, fewer lapses, short lapse duration, and few risk situations are predictive of older adults maintaining an exercise program (Stiggelbout, Hopman-Rock, Crone, Lechner, & van Mechelen, 2006). Maintenance may also be affected by cues to action, such as frequent phone calls or mailed reminders (Reynolds, 2001).

The measures taken to counteract such barriers can be thought of as facilitators or "determinants" of activity. A determinant is defined as a characteristic that has a predictive relationship with a specific behavior (Dishman & Sallis, 1994). Dishman (1991) has identified categories of personal characteristics, environmental factors, and program characteristics as determinants of physical activity. Determinants may differ by gender. For example, older males are more internally motivated than females, whereas older females place more attention on the social aspect of activity than males (Clark, 1999). In general, older adults enjoy activities shared with individuals who have similar physical capabilities and attitudes. Exercising with persons with similar physical capabilities could influence self-efficacy through vicarious learning, which could in turn influence activity levels (Bandura, 1997). Similarly, watching someone perform an activity previously thought of as too difficult may inspire an individual to attempt it, broadening the spectrum of activity possibilities.

Another well-established yet critical determinant of physical activity participation in older adults is social support (Dishman & Sallis, 1994). Physical activity with a group can be a way to meet new people and build friendships through both competition and cooperation, depending on the activity (Adams, 1993). This premise serves as a motivator for some older adults (Finch, 1997). Older adults who participate in group activities may have increased life satisfaction, decreased loneliness, and a sense of belonging and social support (Bailey & McLaren, 2005; McAuley et al., 2006). King and colleagues (1998) concluded that group-based interventions had higher rates of adherence for the older adult population, based on a review of 29 intervention programs. Similarly, van der Bij and colleagues (2002) found evidence that supports the benefits of team-building activities in older adults.

It may be that group-based interventions of moderate activity are more effective at keeping older adults' interest because their social nature is an attractive quality to older adults. Van der Bij et al. (2002) found that initial participation rates of older adults were 90 percent and 84 percent for home and group-based interventions, respectively. Although participation rates declined with time for both groups, the group-based intervention rates declined at a slower rate. Continuing with this theme, Taylor et al. (2004) suggest that team-building sessions, meetings, reminder phone calls, progress reports, and additional incentives all have a positive effect on participation.

Using a Group-based Approach

Since we know that the current interventions for older adults result in low long-term adherence rates and that there are still low numbers of older adults participating in physical activity on a regular basis, proponents of physical activity need to investigate alternative approaches. In a review of the literature, Conn et al. (2002) determined that interventions involving center-based activity produced significantly higher health benefits than home-based interventions. Incorporating a team or group viewpoint toward sport and activity can incorporate one further determinant of physical activity: social support. Using a team and group approach may be the answer to getting older adults actively engaged in activity. Taking a team approach means planning activities within a group setting, where individuals within the group establish goals together and provide support to others (Carron & Spink, 1993). This differs slightly from a group activity such as aerobics, where many people do the same activity, but do not interact and do not work together towards a common goal. A good example of the team approach is volleyball, in which everyone is on the same court, having different roles but the same overall goal. Team sports, while wide-ranging in their MET levels, can offer moderate levels of physical activity. The research suggests that the team approach has been successful for older adult populations in exercise interventions (Brawley, Rejeski, & Lutes, 2000; Estabrooks & Carron, 1999). Estabrooks and Carron (1999) had adults work together to set a common goal of logging miles to walk across the province of Ontario and then work together to meet their goal. The team- or group-mediated approach was also successful in increasing adherence to an exercise intervention in a group of people 65 and older (Brawley et al, 2000).

Competition within a team role may also provide a reason to remain active. A study on breast cancer survivors participating in dragon boat racing showed that the athletes trained consistently in order to remain competitive and they also led a physically active life outside of formal training (Culos-Reed, Shields, & Brawley, 2005). Many older adults also enjoy the exhilarating aspect of competition that can occur with team activity. In preparation for competition in the Seniors' Games, many of the athletes began training several months before the competition and arrived with high levels of motivation and enthusiasm and eager to compete (Clark, Ebran, Graham, & Thornton, 2003). The summer Senior Olympic Games held in Virginia in 2003 had over 27,000 qualifiers (Franklin, Fern, & Voytas, 2004), and similar displays of interest are present in state Senior Olympic competitions and in the Huntsman World Senior Games. This suggests that a lack of interest in competition is not the biggest barrier in physical activity for the senior population. When competition is channeled the right way, sizeable health benefits can result.

Competitive team sports may be an ideal fit for some older adults. Although "old age" is frequently identified as a barrier, one study of senior Olympians revealed that 76 percent of male respondents and 82 percent of female respondents began some form of physical activity after the age of 50 (Fontane & Hurd, 1992). Furthermore, 26 percent of those men and 45 percent of those women had not participated in high school or collegiate athletics. A 101-year-old Senior Olympian became the oldest United States track and field competitor in the 60-yard dash and shot put in March, 2003 (Franklin et al., 2004). He began competing in track and field at the age of 80, after dropping out of the sport for almost 50 years. These findings suggest that for some individuals, age alone is not a barrier to being physically active, regardless of previous history of sports participation. Older adults report a wide variety of reasons for participating in sport, including disproving the stereotypes of aging, general enjoyment, social interaction, competition, physical health benefits, and mental health benefits (Dionigi, 2006). By participating in competitive athletics, older adults feel they are better able to cope with aging because, although aging is inevitable, participation in sport improves the quality of their remaining years (Dionigi, 2006).

Accommodating the needs and desires of older adults will help to ensure a pleasurable activity experience. Describing the development of the Seniors' Games, Clark et al. (2003) stressed the importance of including everyone (visually impaired, amputees, wheelchair users, etc.). This is a simple premise, but it carries significant validity. By incorporating a large number of older adults, many of the previously discussed barriers can be overcome. Carpooling to practice, for example, can solve transportation difficulties while enhancing social support and improving self-efficacy through vicarious learning.

Team-based competitions for older adults such as the Seniors' Games, Senior Olympics, and the Huntsman Games seem to have a large following. This concept could be scaled down and applied locally on a community level within senior and recreation centers. Having regular, public competitions in a variety of team sports may stimulate a larger number of older adults to become physically active and to re-adopt old hobbies or become involved in a new activity. There are many types of activities ranging from the traditional sports and team activities (e.g., softball, volleyball, badminton) to other games such as bocce, shuffleboard, and horseshoes. These types of activities rely on the team-building concepts of the group environment. They include the establishment of a group identity (e.g., a group name, such as the "Delaware Dunkers"), group structure (assigning specific roles such as the setter in volleyball), and group processes (interaction and communication among team members, such as on-court encouragement).

In conclusion, given that 40 percent of older adult females ages 70 and over and 30 percent of males ages 70 and above do not participate in any regular physical activity (Centers for Disease Control and Prevention, 2005) and that the drop-out rate after six months in any type of traditional physical activity program is approximately 50 percent (Dishman & Sallis, 1994), practitioners must strive to do a better job in recognizing the special requirements of seniors who participate in physical activity. Table 1 lists some of the factors that should be considered when trying to facilitate physical activity participation among older adults.

This article discussed the possible benefits of team-based interventions in improving these numbers. Modification to existing programs should center on meeting not only the physical but also the psychological and emotional needs of the aging population, keeping in mind that social support is among the most important determinants of physical activity. New programs should aim to alleviate the barriers that older adults face by striving for a high degree of accessibility and a balance between competition and cooperation, depending on the population served. These types of programs focusing on team building can be easily implemented in a variety of settings such as community centers, senior centers, and outdoor recreation areas. For example, a group of older adults in Hockessin, Delaware, frequently plays volleyball at the local police athletic facility in the mornings when the facility is not being used. Similarly, at a local senior center in Newark, Delaware, older adults gather outside to play horseshoes while another group plays water volleyball. The social support aspect is further enhanced when teammates gather for lunch after the activity.

Most importantly, it is necessary to maintain constant communication with older adults who are participating in the program to determine what can be done to improve it. This communication can be informal through group discussions or formal through the implementation of a periodic evaluation survey. By listening to the ideas of older adults participating in team activities and doing whatever is necessary to see those ideas through, the needs of new participants can be met and the physical activity adherence of those already involved in the program will increase.

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Elizabeth Orsega-Smith (eosmith@udel.edu) is an associate professor, Nancy Getchell is an associate professor, Kevin Neeld is a student, and Sam MacKenzie is a student, in the Department of Health, Nutrition & Exercise Sciences at the University of Delaware in Newark, DE 19716.

Table 1. Factors in Facilitating Physical Activity Participation Among
Older Adults

Facilities
Multi-use trails
Local parks
Playgrounds
Schools
Fitness centers
Senior centers
Community centers
Municipal athletic facilities

Programming
Use team sports (e.g., basketball, volleyball, softball, badminton).
Incorporate leisure activities.
Promote crossover with aerobic or strength conditioning programs.

Access
Choose site close to bus stop.
Provide list of people willing to carpool.
Set up alternative plans for inclement weather conditions.

Costs
Strive for low costs and flexibility.
Obtain sponsors.
Conduct fundraisers.

Social Support & Other Determinants
Provide encouragement and positive comments.
Create incentives/goals.
Find appropriate balance between cooperation and competition.
Provide opportunities for individual attention.
Encourage spousal participation.