Understanding the Barriers to Physical Activity for Cancer Patients.

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Journal of Psychosocial Oncology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/wjpo20

Understanding the Barriers to Physical Activity for Cancer Patients a

Dr. Lawrence R. Brawley PhD , Dr. S. Nicole Culosb

c

Reed PhD , Ms. Jennifer Angove MSc & Dr Laurie Hoffman-Goetz PhD

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Department of Kinesiology , University of Waterloo , Waterloo, Ontario, N2L 3G1, Canada b

Faculty of Kinesiology , University of Calgary , Calgary, Alberta, Canada c

Department of Kinesiology , University of Waterloo

d

Department of Health Studies and Gerontology , University of Waterloo Published online: 12 Oct 2008.

To cite this article: Dr. Lawrence R. Brawley PhD , Dr. S. Nicole Culos-Reed PhD , Ms. Jennifer Angove MSc & Dr Laurie Hoffman-Goetz PhD (2003) Understanding the Barriers to Physical Activity for Cancer Patients, Journal of Psychosocial Oncology, 20:4, 1-21, DOI: 10.1300/J077v20n04_01 To link to this article: http://dx.doi.org/10.1300/J077v20n04_01

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Understanding the Barriers to Physical Activity for Cancer Patients: Review and Recommendations Lawrence R. Brawley, PhD S. Nicole Culos-Reed, PhD Jennifer Angove, MSc Laurie Hoffman-Goetz, PhD

ABSTRACT. For individuals who experience cancer, regular adherence to physical activity has been shown to provide benefits ranging from alleviation of symptoms to improvements in physical function and quality of life. However, research about barriers to participation that compromise adherence and subsequent benefits has been identified as needed. The purposes of this article were to (1) systematically review the barriers to research and make recommendations, (2) consider unique symptoms of disease and treatment regarding their barrier-related impact on exercise therapy, and (3) present an organizational framework that will aid the investigation and understanding of barriers as they affect adherence to prescribed exercise therapy for cancer treatment and recovery. [Article copies available for a fee from The Haworth Document Delivery Service: 1-800-HAWORTH. E-mail address: Website:  2002 by The Haworth Press, Inc. All rights reserved.] Dr. Brawley is Professor, Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada (E-mail: [email protected]). Dr. Culos-Reed is Assistant Professor, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Ms. Angove is a Doctoral Student, Department of Kinesiology, and Dr. Hoffman-Goetz is Professor, Department of Health Studies and Gerontology, University of Waterloo. The project was supported by the Centre for Behavioral Research and Program Evaluation, a National Cancer Institute of Canada-funded center. Journal of Psychosocial Oncology, Vol. 20(4) 2002 http://www.haworthpress.com/store/product.asp?sku=J077  2002 by The Haworth Press, Inc. All rights reserved. 10.1300/J077v20n04_01

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KEYWORDS. Physical activity, exercise therapy, exercise barriers, adherence, research, recommendations Physical inactivity has been identified as among the major risk factors for the prevalence of chronic diseases, including cancer (Blair & Connelly, 1996). However, this risk factor, as well as others, can be modified and often is under the control of individuals with regard to prevention of disease, promotion of personal health, and rehabilitation. REVIEW OF THE LITERATURE Physical Activity for Prevention and Rehabilitation A recent and encouraging preventive viewpoint is that increased physical activity is associated with reduced risk of overall mortality from cancer and, in particular, of developing breast, colorectal, prostate, and gynecological cancers (Shephard & Shek, 1998). The most consistent evidence for this association is found in the research on physical activity and colon cancer (Marrett et al., 2000), and there is increasing evidence of a probable relationship between physical activity and breast cancer (Marrett et al, 2000; Pinto & Marcus, 1994). However, the exact risk-reducing mechanisms of physical activity have yet to be identified (Hoffman-Goetz, 1998b). Physical activity also has been examined as a rehabilitative behavior for people being treated for or recovering from cancer. The vast majority of individuals undergoing cancer treatment are in Stage I or II of the disease. The research and reviews to date have focused on the recovery of patients with breast and colorectal cancer or on physical activity during treatment with samples with breast and mixed cancers (e.g., Courneya, 2001; Courneya et al., 1999). The results of these studies indicate that physical activity may provide a useful means for maintaining functional ability and reducing the limitations imposed by the side effects of treatment (e.g., nausea, fatigue, pain) (Hoffman-Goetz, 1998) and that physical activity is associated with improved quality of life (Courneya, 2001). Adherence to physical activity to counter these negative effects may be one route of improving the well-being of recovering patients. However, this idea seems almost counterintuitive, given the host of symptoms and potential contraindications faced and the lingering side effects over the weeks and months that follow during recovery (cf. Courneya, 2001). The Problem of Adherence Despite the overall positive findings concerning the role of physical activity for both prevention of cancer and rehabilitation after cancer, a number of areas


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require further inquiry. Chief among them is the problem of adherence to rehabilitative and preventive prescriptions. For prescriptions for physical activity to be successful, patients must persist and adhere to the recommended program (i.e., initiate and maintain their participation in physical activity). As well, adherence to physical activity regimens after intervention is a crucial issue; however, unlike other areas of chronic disease (e.g., cardiac rehabilitation), adherence to this behavior has been virtually ignored in cancer research. Among the interventions regarding physical activity for cancer reviewed by Pinto, Eakin, and Maruyama (2000) and Courneya (2001), the average follow-up period was less than six months–clearly too short a period to determine the association between long-term behavioral maintenance and the potential associated benefits that regular activity may provide (cf. Dishman, 1994). Given that adherence to exercise is a problem in both asymptomatic and diseased populations with an average dropout rate of 50% at six months (Dishman, 1988, 1994), one can reasonably assume that comparable rates of nonadherence will occur among cancer patients. Similar to the determinants of adherence identified in the literature on physical and mental health, a host of factors have been cataloged by Dishman (1994) in relation to adherence to physical activity. Among the patient, treatment, disease, relationship, and setting characteristics that influence adherence, the barriers with which cancer patients struggle are considerable. To appreciate the influence of barriers to physical activity without the added burden of disease, it is instructive to consider the evidence about adherence for asymptomatic individuals. Among the numerous determinants of nonadherence, barriers to participation is an acknowledged problem (Brawley, Martin, & Gyurcsik, 1998). Barriers have been stressed as a key variable for investigation in major consensus conferences concerning health and physical activity (e.g., Bouchard, Shephard, & Stephens, 1994). As well, perceived barriers feature prominently in major theories used to examine change in health behavior and adherence (cf. Brawley & Culos-Reed, 2000). In two recent reviews of cancer and physical activity, the study of barriers to physical activity was identified as a research need (Courneya & Friedenreich, 1999a; Friedenreich & Courneya, 1996). Several studies investigating physical activity programs during treatment for breast cancer and as part of posttreatment rehabilitation indicated that although the activity programs were feasible and beneficial, further research is needed to identify methods for encouraging adherence (Courneya, 2001; Mock et al., 1994, 1997). Specifically, Mock et al. (1997) challenged future investigators to consider the side effects of cancer treatment (i.e., clearly barriers) as a potential source of nonadherence to remedial physical activity programs.


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One purpose of the present review was to make a systematic beginning to address the gap in the barriers research. However, in doing so, it would be instructive to consider the lessons from our understanding of the barriers to physical activity discussed in the literature for asymptomatic individuals. Brawley, Martin, and Gyurcsik (1998) examined conceptual and methodological issues with respect to the measurement of barriers in health and exercise. Factors identified in their analysis were used to evaluate the published barrier-related literature on cancer and physical activity in our review. These factors are presented first, followed by a brief narrative analysis of the available studies in relation to cancer. A second purpose was to consider the potential of unique symptoms of cancer and its treatment as real barriers to physical activity. It was clear that a systematic, organizational framework had not been considered previously to examine the collective, barrier-related impact of disease or treatment on adherence to recommended physical activity for either treatment or recovery. Our final purpose was to present an organizational framework (e.g., Meichenbaum & Turk, 1987) that could be considered relative to adherence to physical activity for cancer patients. This framework may lead to a better understanding of the impact of barriers as they affect the patients’ efforts to adhere to prescribed exercise therapy for their cancer treatment and recovery. CONCEPTUAL AND METHODOLOGICAL BACKGROUND Barriers Defined The definition of barriers to physical activity varies widely across several areas of investigation (e.g., exercise, leisure, health). However, Bandura’s theoretical conceptualization of barriers (1997) provided a useful frame of reference for the purpose of our review. Bandura proposed that barriers to involvement should be classified as either actual or perceived barriers. Actual barriers may physically prevent a person from initiating a health behavior, such as exercise. This type of physical barrier may include lack of facilities, cost of services, or contraindications associated with the disease or its treatment. Conversely, perceived barriers tend to slow or halt completion of an ongoing health behavior. Perceptions of barriers have been conceptualized as personal (e.g., fatigue, embarrassment, fear) and situational (e.g., inclement weather, lack of time). Perceived Barriers Perceived barriers have been the most common type of barriers examined with respect to adherence to physical activity (e.g., Steinhardt & Dishman,


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1989). This concept of barriers also is included in several theoretical models used to examine health behavior generally and physical activity specifically (e.g., health belief model, Janz & Becker, 1984; transtheoretical model of change, Prochaska et al., 1994; theory of planned behavior, Ajzen, 1985, 1991; self-efficacy theory, Bandura, 1997). Most often, the concept is used indirectly, only as part of a theoretically developed measure of the perceived control people believe they have over their actions. Thus, the influence of these theories on measurement of barriers has been limited. More specifically, measures of perceived control have not been used systematically to investigate directly and to understand perceived barriers to physical activity as a unique psychological construct that may determine behavior and other social-cognitive beliefs (e.g., excuses, self-efficacy). To date, direct measures of barriers have been developed atheoretically. In turn, the problems associated with accurate measurement become compounded. In general, the literature on measurement of barriers to physical activity is characterized by the problem of linking a concept to its operational definition. To avoid problems involving measurement, the conceptualization of the construct must be clear, and the representation of this construct (i.e., barriers) must be accurate and reflect both its breadth and its specificity. Understanding how measurement falls short of these essentials in the literature on barriers offers criteria to evaluate the research about cancer. PROBLEMS IN THE LITERATURE ON BARRIERS Conceptualization Problems The literature on physical activity exhibits inconsistency in the conceptualization of barriers. One common conceptual problem is that reasons, excuses, and attributions are often measured as opposed to true barriers. For example, investigators may encourage respondents to report reasons or excuses for not being involved in exercise (e.g., “The reason I don’t exercise is _______”). People who cite lack of time as an impediment to participating in exercise may be describing a reason or an excuse rather than a barrier. Lack of time may be a socially acceptable excuse that conceals an undesirable reason for not exercising (e.g., laziness). By contrast, a true barrier would be that people may legitimately lack the time or time-management skills to participate in exercise (i.e., a barrier). The importance of drawing the conceptual distinction between real barriers and excuses or reasons lies not only in the measurement of these constructs but also in the potentially different approaches to intervention that would minimize these variables. For instance, a person who uses excuses for not exercis-


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ing may not intend to exercise. Consequently, attempts to eliminate barriers that are actually excuses may not result in more exercise behavior. Lack of facilities may be cited as a barrier in a community study but actually may represent an excuse or reason for not exercising. In this case, if an intervention was designed to construct adequate exercise facilities in the community, increased participation might not be realized (Brawley, Martin, & Gyurcsik, 1998). Different interventions are needed for people who are not ready to be active. Measurement Problems Researchers who investigate physical activity have used a variety of methods to develop measures that examine barriers, including borrowing scales from other literatures, relying solely on their own assumptions, and developing measures from procedures for eliciting barriers from subjects. Borrowing of scales is a particularly important issue because the conceptualization and identification of barriers tends to vary according to the population and behavior from which the scale is borrowed. Consequently, borrowing a barriers scale developed for a different population or behavior may result in either excluding important barriers or including unimportant barriers. For example, dealing with the symptoms of chronic disease may be a barrier to physical activity for the elderly but not for adolescents, and lack of time may be a relevant barrier for adolescents but irrelevant for the elderly. In an attempt to avoid problems associated with using borrowed measures, some researchers have developed the barriers scales used in their studies. However, inasmuch as these scales are based on researchers’ assumptions (i.e., without input by participants), they also can be problematic (e.g., selectivity in inclusion or exclusion of barriers from the scale). Because of the diverse methods and scales used, the variety of measures of barriers used in the general literature on physical activity limits the extent of comparison possible between studies. Drawing conclusions is difficult regarding the scope of the problems of adherence posed by a given barrier and potential moderators (e.g., age, gender) of its effects. Frequency and Strength of Influence A variety of methods have been used to develop quantitative indexes of the impact of barriers on adherence. Depending on whether the development of these indexes was data or theory driven, the quantitative response scale will vary. Regardless of the quantitative response scale used, many indexes of barriers have the inherent problem of aggregating multiple noninfluential barriers with influential barriers. For example, although differences in barrier scores between exercise adherers and nonadherers have been reported, an inspection


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of the degree of influence attributed to barriers that is being compared indicates that the strength of the total influence is low to moderate. As well, the overall number of different barriers is often reported, but without any idea of the frequency of their occurrence (e.g., times per week or month). The percentage of a sample reporting a type of barrier is described, but the influence of the barrier remains unknown without evidence of frequency. Brawley, Martin, and Gyurcsik (1998) argued that the failure of researchers to differentiate barriers of low strength and frequency from barriers that are influential (i.e., within a barrier index) leads to a faulty interpretation of the influence of important barriers (i.e., interpreting indexes where the influence of true barriers is diluted by multiple noninfluential ones). Design Problems The problems of measuring key barriers are often exacerbated by problems of study design. Many studies in the literature on physical activity are characterized by cross-sectional retrospective designs, where participants are asked to recall the influence of barriers on their physical activity at some point in the past for either specified or unspecified periods of time. Measurement of perceptions in retrospective research designs is inherently constrained by the capacities of human memory that influence a person’s ability to remember and identify barriers accurately. Increasing the length of time between the experience of the barrier and its recollection further compounds this problem. For example, requiring a person to recall barriers encountered two weeks ago may be a strategy less prone to error in recall than is inquiring about barriers experienced years ago. In addition, retrospective descriptive studies that use a previously elicited list of barriers assume that barriers are stable constructs. However, people may encounter novel barriers or develop coping strategies to deal with constraints that previously impeded behavior. The changing nature of barriers (e.g., transient, managed) may alter the degree to which the barrier limits adherence. Obviously, retrospective designs do not offer the opportunity to examine this type of change. The problems characteristic of the general literature on physical activity in relation to conceptualization and measurement of barriers and to study design must be avoided when conducting research on physical activity and cancer. However, it would be prudent to consider whether the cancer literature has these problems and, if so, to recommend solutions. Barriers to Patients’ Physical Activity For the review of this literature, we systematically searched several databases, including CancerLit, PsychInfo, and MedLine, using Klassen, Jadad,


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and Moher’s recommendations (1998) for conducting systematic reviews. Our goal was to identify studies examining barriers to physical activity for patients with cancer. The search terms used to select studies for review included combinations of the following: “barriers or obstacles,” “physical activity or exercise” and “cancer.” The systematic search included all empirical studies published in English up to and including March 2000. Despite the array of potential barriers to participation in physical activity encountered by cancer patients (cf. Courneya & Friedenreich, 1999b), the computerized search of several databases resulted in the detection of only nine published studies (including one abstract by Perna et al., 1997) that specifically considered barriers to exercise or physical activity and cancer (Cooper, 1995; Courneya & Friedenreich, 1997c, 1999a, 1999b; Courneya et al., 1999; Leddy, 1997; Nelson, 1991; Perna et al., 1997; Schwartz, 1998; YoungMcCaughan & Sexton, 1991). A further search of these nine publications by hand resulted in no additional pertinent documents. Closer examination of the nine studies revealed that only two were conducted for the primary purpose of identifying barriers to physical activity (Leddy, 1997; Perna et al., 1997), although the remaining seven identified information relevant to barriers. To assess content and quality, we reviewed each study with respect to design, characteristics of samples, assessment of barriers, and results. Eight studies restricted examination of barriers to people with either breast or colorectal cancer, and the remaining study considered other types of cancer (Schwartz, 1998). The nine studies are presented in Table 1. Upon inspection, it is clear that this limited research is characterized by a host of problems. The conceptualization and methodology used to measure barriers varied widely among the studies we identified. Within this literature, the studies reflect the compounded problems of (1) borrowing scales that omit important treatment-related barriers, (2) excluding patients who are undergoing treatment, and (3) requiring participants to recall the incidence and effects of treatment-related barriers. Each problem is discussed separately to illustrate their influence on the studies reviewed. MEASUREMENT AND DESIGN PROBLEMS IN RESEARCH Scales Used Five of the nine studies reported in Table 1 either used scales borrowed from studies of barriers in other diseases, such as diabetes, or included lists of barriers that were predetermined by the researchers without using information about social context provided by methods of eliciting barriers. Obviously, the scale borrowed from the literature on diabetes may have included irrelevant disease-specific symptoms and treatment issues foreign to patients with can-


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TABLE 1. Results of the Literature Search: Barriers to Physical Activity Among Patients with Cancer Nelson, 1991. Participants: Number, 55 in cancer group, mean age 67.3 years; mean age 67.2 years in matched noncancer cohort. Type of cancer: Breast, Stage I disease: mean time since diagnosis, 57.5 months. Design: Cross-sectional. Theory: Health belief model (perceived benefits and barriers). Measure: Exercise Benefits/ Barriers Scale: 43 items, 4-point scale (Strongly agree to Strongly disagree). Total score used. Barriers: Total score = unable to discern which barriers were salient. Results: Significant difference between groups on benefits and barriers. Matched cohorts scored higher. Problems 1-4.* Young, McCaughan, & Sexton, 1991. Participants: Number, 71; mean age, 60.2 years. Type of cancer: Breast, mostly Stage I. Design: Retrospective. Theory: None. Measure: Perceived Barriers to Exercise Scale from diabetes literature: 5-point scale (Strongly agree to Strongly disagree. Total score used: high score = few barriers. Barriers: Some seemed to be beliefs (e.g., “I believe that exercise helps me control my weight”). Results: Exercise group perceived significantly fewer barriers to exercise than nonexercise group did. No significant difference between groups in number of health conditions precluding exercise. Problems 1-4.* Cooper, 1995. Participants: Number, 75; mean age, 49 years. Type of cancer: Breast; majority, 2-3 years postdiagnosis. Design: Retrospective. Theory: None. Measure: Developed by investigator. Open-ended question: “What obstacles did you face to becoming physically active after treatment?” Barriers: Multiple responses. Results: Most commonly mentioned obstacles: pain (53%), fatigue (37%), feeling embarrassed (33%). Women who reported facing more obstacles took longer to become physically active again. Women who “felt embarrassed” or “lacked encouragement” took the longest returning to physical activity. Problems 1-4.* Leddy, 1997. Participants: Number, 11 in Phase 1; mean age, 43 years. Sixty-four in Phase 2; mean age, 47 years. Type of cancer: Breast. Design: Retrospective. Theory: Decisional balance (health belief, transtheoretical, and TRA models). Measure: Incentives and Barriers to Exercise Scale, developed by investigator: 16 items, 1-10 rating of influence, decisional balance index (DBI) = sum incentivessum barriers. Positive DBI = more incentives than barriers. Barriers: Time, inertia, not in routine, boring, fear of injury, little energy. Results: DBI in exercise group significantly higher than in rarely exercise group. Total group mean, DBI = +19. Most important barriers: time, inertia, not in routine. Problems 2 & 4.* Courneya & Friedenreich, 1997c. Participants: Number, 110; mean age, 61 years. Type of cancer: Colorectal. 85% had Stage or II disease; mean time since diagnosis, 26.5 months. Design: Retrospective. Theory: Planned behavior. Measure: Seven control beliefs: 7-point scale (Extremely false to Extremely true). Mean score: belief-based measure of perceived behavioral control. Barriers: Control beliefs: nausea, fatigue, no time to exercise, no support, no counseling, pain/soreness, work at regular job (dropped from scale). Results: Most important control beliefs: fatigue, no time to exercise, pain/soreness. Problems 2 & 4.*


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JOURNAL OF PSYCHOSOCIAL ONCOLOGY TABLE 1 (continued)

Perna et al., 1997. Participants: Number, 57. Type of cancer: Breast, Stage I & II, 3 months postsurgery. Design: Unknown. Theory: Stages of change. Measure: Perceived barriers to exercise. Barriers: Caring for children, self-consciousness regarding appearance. discouragement by others and fear of injury differentiated exercisers from nonexercisers. Results: Nonexercising lumpectomy patients gave highest-perceived-barriers ratings. Exercising mastectomy patients gave lowestperceived-barriers ratings (except self-consciousness). Perceived barriers and negative affect may be related to exercise behavior soon after surgery. Problems 1-4.* Schwartz, 1998. Participants: Number, 219; physically active. Type of cancer: Mixed. Design: Cross-sectional. Theory: None. Measure: Motives and barriers questionnaire developed by investigator. Barriers: Physical symptoms during and after treatment. Results: Most difficult physical symptoms: aching muscles, fatigue, dehydration, diarrhea. Primary barriers during and after treatment: time, tiredness. Patients with testicular cancer cited significantly more barriers to exercise then other patients did. “Too tired” was cited by surgery patients. Exercise was interrupted least among patients with prostate cancer. Problems 1-4.* Courneya & Friedenreich, 1999b. Participants: Number, 164; mean age, 53 years. Type of cancer: Breast; 87% had Stage I or II disease; mean time since diagnosis, 17.5 months. Design: Retrospective. Theory: Planned behavior. Measure: Seven control beliefs: 7-point scale (Extremely false to Extremely true). Barriers: Control beliefs: nausea, fatigue, no time, no support, pain/soreness, no exercise counseling, work (dropped from scale). Results: Number of weeks of adjuvant therapy was significantly negatively correlated with control beliefs. Most important control beliefs: no time, no support for exercise. Problems 2 & 4.* Courneya et al., 1999. Participants: Number, 66 (57.6% male); mean age, 60.8 years. Type of cancer: Colorectal; 83% Stage II or III. Design: Prospective. Theory: Planned behavior. Measure: Seven control beliefs: 7-point scale (Extremely difficult to Not at all difficult). Barriers: Control beliefs: experiencing nausea, fatigue, no time to exercise, no support, pain/soreness, no exercise counseling, work at regular job (dropped from scale). Results: Most important control beliefs: fatigue, no counseling for exercise, experienced pain/soreness. Problem 4.* *Problems: 1 = scale borrowed/based on researchers’ assumptions, 2 = retrospective/ cross-sectional design, 3 = strength not assessed, 4 = frequency not assessed.

cer. As well, potential barriers to physical activity that are unique to the cancer experience (e.g., breast removal, hair loss, diarrhea) would not be included in a barriers scale borrowed from a population with another chronic disease. The studies that used measures based on investigators’ assumptions presented barriers (i.e., concerns about personal safety, lack of money, had to work at your regular job) that were not reported by any participants in certain


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studies (e.g., Schwartz, 1998). Different barriers to adhering to physical activity therapy are associated with unique disease variables and side effects of treatment. Because five of the studies did not use elicitation procedures, what they add to this literature is questionable. Few studies to date have attempted to elicit salient barriers. However, Leddy (1997) and Courneya and Friedenreich (1997c) used elicitation procedures to identify salient barriers associated with physical activity among people with a history of cancer. The scale developed by Courneya and Friedenreich (1997c) to assess barriers also was used in their subsequent studies (Courneya & Friedenreich, 1999b; Courneya et al., 1999). Recall: A Design Problem Of the nine studies reviewed, the majority used retrospective or cross-sectional designs, whereas only one study used a prospective design (Courneya et al., 1999). A number of retrospective studies required participants to recount the incidence or effects of treatment-related barriers several years after their occurrence. For example, the mean time since completion of treatment in Schwartz’s study (1998) was 42.5 months, and Leddy (1997) included subjects who had been treated within the past 10 years. Although many potential barriers for people with cancer are related to symptoms and side effects of treatment (i.e., nausea, fatigue, pain, muscle weakness), several of the studies reviewed excluded patients undergoing treatment, thereby relying on people well past treatment recalling side effects of treatment as barriers. Because the recalled descriptions from the available studies cannot be validated, they must be questioned for reasons of recall bias. Strength and Frequency of Limitation The extent of the limitation imposed by barriers was assessed in four of the studies (Courneya & Friedenreich, 1997c, 1999b; Courneya et al., 1999; Leddy, 1997). For example, Courneya and Friedenreich (1997c) assessed the strength with which each barrier influenced exercise behavior as part of their perceived control measurement. However, they did not use the component of strength in their analyses in that study or in subsequent studies. The presentation of the strength of the barriers may have added a descriptive dimension to their work that is lacking in the other studies reviewed. As another example, Leddy (1997) measured the perceived amount of influence that each barrier had on respondents’ decision to exercise. However, the frequency with which barriers occurred was not measured. Although the barriers identified in Leddy’s study as most influential were lack of time, inertia, and lack of exercise in the daily routine, whether the barriers occurred often enough to diminish adherence is uncertain. It is important to note that none


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of the nine studies evaluated the frequency with which respondents encountered the barriers being measured. Consequently, the literature lacks information on the true extent of the problems posed by barriers. GUIDELINES FOR IMPROVING RESEARCH The current research poses a number of inherent problems and limitations. Brawley, Martin, and Gyurcsik (1998) suggested several guidelines for improving the detection, measurement, and understanding of barriers in the general literature on physical activity that can be applied to cancer and physical activity. First, given the complexity of cancer and its combined treatment modalities, different types of barriers to physical activity and the social context in which they occur are unclear. Therefore, procedures for eliciting respondents’ barriers should be used as a first step during development of scales to identify the unique and diverse biological and psychosocial impediments people experience when they engage in exercise therapy. Allowing participants in elicitation studies to determine the content of scales beforehand improves the likelihood that the barriers included in the study are meaningful and that relevant barriers are not omitted. Second, using prospective study designs to detect current and anticipated barriers may be useful. Prospective designs are less likely to create recall problems and more likely to promote accurate detection of barriers. Prospective investigations of barriers allow the comparison of current barriers to previously reported constraints. This enables the researcher to determine whether the barrier is stable or variable. For example, Mannell and Zuzanek (1991) used an experience-sampling methodology over a prospective time period, where participants were required to sample barriers to activity randomly during their day. This methodology allowed for a variety of advantages, including the ability to verify whether the influence of a barrier was stable (i.e., consistently reported) or transient. Third, information should be collected regarding the frequency and perceived strength of the limitation imposed by important barriers to adherence to exercise. Simple agreement or disagreement concerning whether a barrier may be a problem does not provide sufficient relevant information. It would be useful to measure the frequency with which a barrier occurs and whether its perceived strength as a limitation is sufficient to impede participation in physical activity. Brawley, Martin, and Gyurcsik (1998) argued that a method of weighting is necessary in which both the perceived strength of a barrier’s limitation and the frequency of its occurrence are accounted for. For example, people who are ef-


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fective in juggling their daily exercise time may minimize a frequently occurring but modestly influential time barrier. By contrast, people who are using exercise therapy for rehabilitation may be dealing with frequent daily pain, which varies markedly in whether it limits their participation in therapy. Consequently, both frequency and variability of the pain become contributors to an ongoing limitation for exercise, particularly when a person lacks an effective means of coping. Such measures may help to attenuate some of the biases in interpretation evident in various investigators’ discussions of barriers to adherence. DISEASE- AND TREATMENT-RELATED BARRIERS It is clear that cancer and its treatment are associated with a host of potential symptoms and side effects of treatment that act as barriers to adhering to exercise. These barriers were not measured well in the studies we reviewed. However, we offer examples drawn from the cancer literature to underscore the magnitude of potential limitations on adherence to physical activity and the importance of their future measurement. The implications of understanding these limitations are important for interventions. More specifically, HoffmanGoetz (1998a) suggested that prescriptions for exercise should be tailored relative to age, general health, previous history of exercise, stage of cancer, as well as the treatment modality and its related side effects. Clinical recommendations regarding exercise therapy during treatment are made most often for patients with early stage cancer. Because later stages of the disease and its treatment are of greater magnitude and complexity, physical activity may not be recommended. Thus, most of our comments are relative to the potential barriers experienced during earlier stages of disease. Knobf (1990) summarized potential and predictable effects of treatment for primary breast cancer and categorized them as those associated with mastectomy (i.e., reconstruction), with radiation therapy (i.e., breast soreness), and with symptomatology associated with both treatments (i.e., pain, fatigue). Knobf also offered a series of the most common and distressful symptoms of adjuvant therapy’s toxicity (i.e., vomiting, fatigue, hair loss, weight gain). Each symptom should be considered as a potential barrier to physical activity for women with breast cancer. A number of reports and reviews throughout the 1990s examined the more prevalent and consistent side effects of cancer treatment. Fatigue was cited as prevalent and disruptive throughout the cancer experience by Winningham et al. (1994) and in a review of 25 studies by Irvine et al. (1991), and fatigue was characterized as a prevalent problem after chemotherapy and radiation therapy. Pain also is associated with much of the cancer experience (Ventrafridda,


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Caraceni, & Sbanotto, 1996), whereas nausea and vomiting are suggested as being anticipatory or conditioned side effects of adjuvant chemotherapy (Stockhorst, Klosterhalfen, & Steingrueber, 1998). In addition, negative impacts of treatment on body image and weight gain (Smith & Reilly, 1994) are associated problems (e.g., weight gain with use of prednisone as a part of combination chemotherapy). Weight gain also is common among women treated for breast cancer. An average weight gain of 5 to 14 pounds has been observed, but gains up to 50 pounds have been reported. Such weight gains are more common among premenopausal women who have received a higher dosage of treatment over a longer period or when multiagent treatments are used (Denmark-Wahnefried, Rimer, and Winer’s review of 29 studies in 1997). Finally, contraindications to activity are relevant when dizziness, severe vomiting, or diarrhea are observed when chemotherapy, radiotherapy, or both have been experienced within 48 hours. Prolonged fatigue or muscle weakness and shortness of breath may compromise patients’ involvement in physical activity. These symptoms and side effects of treatment must be considered as potential barriers to physical activity in future research. THE THREAT OF BARRIERS–INACTIVITY Many side effects of treatment that act as barriers may actually be intensified by physical inactivity, including weight gain, fatigue, deterioration of lean muscle mass, and overall reduction in physical functioning (i.e., diminished cardiovascular and pulmonary function). For example, despite the evidence that exercise improves the physiological and psychological functioning of patients with breast cancer (Friedenreich & Courneya, 1996), these women tend to limit their activity after diagnosis. This inactivity is particularly alarming because it may prolong their symptoms. In fact, Pinto, Eakin, and Maruyama (2000) included increased sedentary behavior in their review of changes in health behavior that occur after a cancer diagnosis. To illustrate the potential that disease- and treatment-related barriers have to encourage physical inactivity, a scrutiny of exercise interventions for patients with cancer is useful. Research indicating improvements experienced after participation in exercise therapy is summarized in Table 2. Studies of exercise after a cancer diagnosis have demonstrated that physical activity helps to mitigate common side effects of treatment that are potential barriers, including nausea, reduced physical functioning, fatigue, changes in body composition, pain, and dissatisfaction. Although those studies have demonstrated that exercise is beneficial for cancer patients, engaging in physical activity in the face of these side effects is difficult.


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TABLE 2. Interventions Regarding Physical Activity and Cancer Symptomatology Friedenreich & Courneya, 1996. Number of studies: 9. Design: Four randomized controlled trials, 3 quasi-experimental, 2 retrospective. Type and stage of cancer: Patients in 7 studies had Stage I or II breast cancer, patients in 1 study had Stage II-IV disease, patients in 1 study had Stage I-V disease. Treatment chronology: Patients were undergoing treatment in 6 studies, had mixed treatment status in 2, had completed treatment in 1. Results: Functional capacity (e.g., increased oxygen consumption) improved in 3 studies, nausea decreased in 2, fatigue/sleeping problems declined in 2, body composition (decreased body fat, increased lean body mass) occurred in 1 study, immune function improved in 1, depression decreased in 1. Interventions & adherence: 5 of 7 studies, 10- to 12-week program; 2 of 7, 3- to 6-month program. In 7 studies, cycle ergometer used in 6; walking used in 1. Of 7 studies, 6 were laboratory-based, supervised, individually monitored; 1 was home-based, unsupervised.* Dimeo et al., 1997. Design: Experimental. Type of cancer: Breast cancer in 22 studies, non-Hodgkin’s lymphoma in 14. Treatment & chronology: Aerobic exercise in rehabilitation after completion of high-dose chemotherapy and autologous peripheral stem cell transplantation. Results: Reduced fatigue, improved physical performance. Intervention & adherence: 6-week, supervised, in-hospital walking program. Courneya & Friedenreich, 1999a. Number of studies: 24. Design: Eight studies experimental, 10 quasi-experimental, 6 descriptive. Type and stage of cancer: Stage I or II breast cancer in 14 studies; leukemia in 4; solid tumors in 2; single studies of head and neck, colorectal, childhood cancers, and an unspecified site. Treatment chronology: Patients had completed treatment in 14 studies, were undergoing treatment in 7, had mixed treatment status in 3. Results: Improved functional capacity in 12 studies, improved mood states in 4, improved muscular strength/flexibility in 4, reduced fatigue in 3, increased self-esteem in 2, improved body composition in 2, reduced nausea/diarrhea in 2, decreased pain in 1. Interventions & adherence: In 18 studies, program was less than 12 weeks in 14, 4 to 6 months program in 3, 12 months in 1. Eight of 18 studies used ergometer, 6 used walking, 3 used an unspecified intervention, and 1 used resistance training. Thirteen of 18 studies were laboratory-based, supervised programs; 3 were home-based unsupervised programs; 1 was partially supervised program. Dimeo et al., 1999. Design: Experimental. Type of cancer: Breast cancer in 16 studies, non-Hodgkin’s lymphoma in 4, Hodgkin’s disease in 2. Treatment & chronology: Effects of physical activity on fatigue and psychological status during chemotherapy. Results: Reduced fatigue, improved psychological distress (fear, anxiety). Intervention & adherence: Supervised, in-hospital supine cycling program. *Adherence to exercise considered.


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Although there is obvious interest in the change exhibited by groups participating in exercise interventions, the impact of symptoms of disease and treatment on physical activity is particularly revealing among members of control groups. Specifically, studies of interventions involving exercise that use control groups have reported a trend toward physical inactivity among controls (Mock et al., 1994, 1997). For example, Mock et al. (1997) reported decreased levels of activity among cancer patients receiving usual care. DemarkWahnefried et al. (1997) found that women with Stage I and II breast cancer reduced their levels of physical activity significantly during chemotherapy. Frank-Stromborg and Wright (1984) examined 323 cancer patients’ perceptions of changes in their levels of physical activity after diagnosis and found that 64% noted a decrease in physical activity and 76% experienced curtailed daily activity. The overwhelming majority (95%) reported that their restricted physical activity was the result of physical limitation, pain, weakness, or an inability to control movement. Courneya and Friedenreich (1997a, 1997b) examined patterns of exercise behavior among patients with breast and colorectal cancers and found that individual levels of physical exercise after treatment had declined significantly from prediagnosis levels. Furthermore, prediagnosis levels of activity were not regained one to four years after treatment ended. Given the trend toward inactivity and the corresponding struggle necessary to reduce the side effects of treatment among cancer patients (e.g., challenging oneself to exercise when feeling nauseous), it is important to identify the facets of the cancer experience that prevent this population from engaging in and adhering to therapeutic physical activity. ADHERENCE: A COMPLICATED PROBLEM Earlier, we referred to Meichenbaum and Turk’s organizational framework (1987) for considering adherence to treatment. Because physical activity and more formal exercise therapy are recommended as effective means of alleviating the symptoms associated with cancer treatments, an understanding of the impact of all therapies on adherence to exercise is needed. The organizational framework for factors related to adherence includes variables associated with the patient, the disease, and its treatment and the interactive relationship between patients and health care providers, including the exercise leader, therapist, nurse, and physician. This framework has been used to consider an array of variables related to adherence to many types of treatment behavior. Below, we offer brief examples relative to the cancer experience.


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Patient Variables Cancer patients may perceive conflicting health benefits. An example is the paradox of knowing that physical activity may eventually alleviate certain symptoms related to cancer treatment but also knowing that these symptoms (i.e., nausea, fatigue, pain, concerns about body image) concurrently discourage participation. Similarly, a lack of understanding about expectations and progress regarding the alleviation of symptoms are patient variables that could affect adherence. Related to patients’ expectations and satisfaction is their eventual belief in the efficacy of the treatment. For example, slow progress in the effectiveness of treatment can lower patients’ belief in its efficacy. Disease and Treatment Variables Because detection and treatment of cancer and rehabilitation take time, the disease has a chronic aspect. Furthermore, a variety of symptoms accompany the disease, and their stability has the potential to affect adherence. For example, the stability of variable pain, ongoing nausea, and psychological depression have been shown to influence adherence to various cancer treatments (e.g., Courneya, 2001). Treatment encapsulates numerous aspects of care, ranging from the amount of time a person must wait between referral and actual first treatment to the characteristics of treatment to the medical side effects of specific aspects of treatment. It is not uncommon for patients to experience multiple therapies that increase the complexity of treatment. This complexity is exacerbated further by the duration of treatment and its side effects. Meichenbaum and Turk (1987) noted that the more protracted the therapy, the greater the risk that patients will not adhere to many types of medical treatments. They also reported studies of increasingly complex treatment across different diseases and different types of treatment regimens (e.g., Glasgow, McCaul, and Schafer’s diabetes treatment triad, 1986), noting that the more complex the treatment, the poorer the rate of adherence. Although a number of explanations exist for the relationship between the complexity of and nonadherence to treatment, complexity about treatment may be the sum total of (1) information overload about what to do, (2) when to do it, (3) how to cope with side effects, and (4) regular repetition of the complex regimen. The sum total of this information represents a barrier imposed by the prescription of this complex regimen. Relationship Variables Last, but certainly not least, is the relationship between the health care provider and the patient. Examples of aspects of the relationship that influence adherence are inadequate communication about the disease, the treatment


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regimen, and the side effects of treatment; the provider’s failure to elicit the patient’s comments about negative reactions or feedback with respect to treatment regimens; and the patient’s or provider’s dissatisfaction with the relationship. Central to this relationship is the provider’s attitude and style of communication throughout the process of treatment and recovery (see Rand & Sevick, 2000). For example, if the provider views cancer as a genetic-cellular disease less amenable to the effects of interventions designed to change life-style, what kind of advice will the provider offer regarding the role of physical activity in cancer prevention and recovery? It is important to consider this treatment-adherence organizational framework relative to cancer and the therapeutic use of physical activity for rehabilitation. Clearly, several complex issues in cancer treatment enlarge the number of potential barriers to adhering to exercise well beyond those faced by normal or healthy exercisers. FUTURE RESEARCH On the basis of the information reviewed here, it is clear that efforts must go beyond simply identifying the need for more research that concerns barriers to physical activity among cancer patients. Thus, we suggest three broad recommendations. First, the use of frameworks such as that offered by Meichenbaum and Turk (1987) will systematically help to identify areas most probable, and possibly most needed, for identification of barriers to physical activity during treatment or intervention. Second, once the focus for study has been identified, researchers must attempt systematically and accurately to measure and examine the multitude of potential barriers to adherence using the recommendations concerning measurement made earlier. Third, because barriers are part of the conceptualization of perceived control central to a number of theories of health behavior and behavioral change (cf. Brawley & Culos-Reed, 2000; Rejeski et al., 2000), the importance of guiding future barriers research using theory is essential for progress. By understanding the impact of barriers on motivational processes and adherence, the goal of enhancing the physical and mental well-being of people with cancer and improving their health-related quality of life may be a step closer. REFERENCES Ajzen, I. (1985). From intentions to actions: A theory of planned behavior. In J. Kuhl, & J. Beckmann (Eds.), Action control: From cognition to behavior (pp. 11-40). Berlin: Springer-Verlag. Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211.


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Received: June 5, 2001 Accepted: February 5, 2002

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