Self-efficacy and imagery use in older adult exercisers

Transcription

1 European Journal of Sport Science, December 2006; 6(4): ORIGINAL ARTICLE Self-efficacy and imagery use in older adult exercisers NATASCHA N. WESCH, MARCIA I. MILNE, SHAUNA M. BURKE, & CRAIG R. HALL School of Kinesiology, The University of Western Ontario, London, Ontario, Canada Abstract The aim of the present study was to investigate the relationship between self-efficacy and imagery use in older male (n/40) and female (n/ 52) exercisers. Participants self-efficacy was evaluated using the Self-Efficacy Questionnaire for Exercisers, and their use of imagery was evaluated using the Exercise Imagery Questionnaire. Results revealed that older adult exercisers were most efficacious in terms of the task, followed by scheduling physical activity into their daily routines, and finally overcoming barriers related to physical activity. Older adult exercisers also reported using appearance and technique imagery to much the same extent, but used both significantly more than energy imagery. In addition, energy imagery predicted task self-efficacy but none of the three functions of imagery predicted barrier and scheduling self-efficacy. Keywords: Self-efficacy, imagery, older exercisers, exercise participation Introduction The physical and psychological benefits of physical activity are substantial and have been well documented, yet 57% of Canadians aged 18 and older, onethird of the American population age 50 and over, and 66% of adults in the UK over 65 are considered insufficiently active for optimal health benefits (Canadian Fitness and Lifestyle Research Institute, 2002; Centers for Disease Control and Prevention, 2004; Department of Health, 2000). Furthermore, the proportion of those who are physically inactive increases with age. Physical activity undertaken by older adults is of particular concern because individuals aged 65 years and over constitute one of the fastest growing population groups, and carry the highest load of chronic disease, disability, and healthcare utilization (King, Rejeski, & Buchner, 1998). Moreover, for the elderly individual, insufficient physical activity can result in activity restrictions, reduced mobility, increased morbidity, and potentially loss of independence (O Brien Cousins, 1997). Previous research involving older adult populations has shown that physical activity is effective in reducing and/or preventing the functional declines that normally accompany ageing (van der Bij, Laurant, & Wensing, 2002). For example, older adults who are physically active show improved cardiovascular function (Green & Crouse, 1995), reduced risk of falling (Province, Hadley, & Hornbrook, 1995), and reduced loss of muscle mass and strength (American College of Sports Medicine, 1998). Nevertheless, many older adults are not participating in sufficient physical activity or exercise programmes to delay disease and increase quality of life (Courneya, 1995; Marcus, 1995). Specifically, more than 50% of adults aged years, and 65% of those over 75 years, do not participate in any leisure-time physical activity (Schoenborn & Barnes, 2002). Furthermore, fewer than 10% of older adults participate in any form of vigorous physical activity (US Department of Health and Human Services, 1991). Shephard (1997) suggested that exercise participation in older adults may be linked to their self-efficacy for exercise. Older individuals frequently underestimate their physical abilities, and this could be one reason for their lesser involvement in physical activity. Self-efficacy reflects an individual s beliefs in his or her ability to engage in behaviours that will yield a desired outcome (Bandura, 1986). It relates to one s sense of competency and proficiency, and therefore affects one s choice of Correspondence: M. I. Milne, School of Kinesiology, 3M Centre, The University of Western Ontario, London, ONT N6A 3K7, Canada. mmilne2@uwo.ca ISSN print/issn online # 2006 European College of Sport Science DOI: /

2 198 N. N. Wesch et al. behaviour, activity, and exerted effort (Strauser, 1995). Self-efficacy has been consistently related to physical activity participation through its established predictive influence on both the adoption and maintenance of physical activity (Bandura, 1997). More specifically, self-efficacy research in younger populations has demonstrated that those who report higher exercise-related self-efficacy exercise more frequently and are more likely to continue exercising in the future (Godin et al., 1994; Marcus, Pinto, Silken, Audrain, & Taylor, 1994; Rodgers & Gauvin, 1998). In older adults, self-efficacy research has yielded similar results. For example, McAuley (1993) found self-efficacy to be very important in the initial adoption of exercise in sedentary adults. Furthermore, in a 6-month randomized control trial with an 18-month follow-up, McAuley, Jerome, Elavsky, Marquez and Ramsey (2003) found that self-efficacy plays a pivotal role in long-term exercise participation in adults aged years. Given these results, it is apparent that self-efficacy is an essential component in exercise participation among older adults. Consequently, Brassington, Atienza, Perczek, DiLorenzo and King (2002) suggested that more attention should be given to increasing confidence in the elderly to help them achieve significant fitness outcomes. One limitation of the above studies is the varying operationalization of self-efficacy. Some investigators have examined individuals confidence in overcoming barriers to exercise, and others have addressed confidence in one s ability to engage in specific types of exercise. Accordingly, Maddux (1995) proposed that it is useful to assess different types of selfefficacy and current exercise psychology research has focused on three types: task, barrier, and scheduling self-efficacy (DuCharme & Brawley, 1995; Rodgers, Hall, Blanchard, McAuley, & Munroe, 2002a; Rodgers & Sullivan, 2001). Task self-efficacy is described as the confidence in one s ability to perform the fundamental aspects of a task in a specific situational context (Maddux, 1995). Barrier selfefficacy is defined as confidence in one s ability to perform a task under challenging conditions or to overcome social, personal, and environmental constraints. Scheduling self-efficacy is the confidence in one s ability to schedule or plan strategies for carrying out a specific action. Support has been provided for the distinction between the three types of self-efficacy in exercise contexts (e.g. Rodgers & Sullivan, 2001), although they have yet to be measured in an older adult population. On account of self-efficacy s potential to influence exercise participation, many suggestions for enhancing exercise self-efficacy have been made. One such suggestion has been the use of mental imagery. Hall (1995) has proposed that individuals who imagine themselves in an exercise situation, performing the way they want to perform, may increase their selfefficacy. Furthermore, Bandura (1986) stated that visualizing (imagining) other people perform successfully can increase one s confidence that one too can master the same activities. In a study examining imagery use in exercisers, Hausenblas, Hall, Rodgers and Munroe (1999) found that exercisers use imagery for three primary functions: technique, appearance, and energy. Technique imagery involves imaging the performance of exercise movements and represents a cognitive function of imagery. Appearance imagery addresses the physical outcomes of exercise such as being fitter and leaner. Finally, energy imagery represents the affective outcomes of exercise such as feelings of being energized or psyched up. Both appearance and energy imagery are motivational functions. Gammage, Hall and Rodgers (2000) found that male and female exercisers reported using appearance imagery the most and energy imagery the least. In addition, males and females differed in their imagery use, with males using more technique imagery and females using more appearance imagery. Recently, Milne, Burke, Hall, Nederhof and Gammage (2005/6) compared exercise imagery use in older and younger adult exercisers. They found that participants in both age groups showed the same pattern of imagery use, with appearance imagery being used most frequently, followed by technique and energy imagery. However, there were some differences between the two age groups with younger exercisers using more appearance imagery than older exercisers, and younger female exercisers using less technique imagery than their older female counterparts. Given that self-efficacy influences exercise participation by older adults, one aim of the present study was to examine the three types of self-efficacy (i.e. task, barrier, and scheduling) in older adults who participate in regular exercise. Research conducted with a younger sample of exercisers and nonexercisers (mean age 38 years) revealed that those who exercised more often (three times a week or more) reported higher task, coping (barrier), and scheduling efficacy (Rodgers & Sullivan, 2001). However, the reported task efficacy scores were higher than the coping and scheduling efficacy scores. Based on that research, we hypothesized that the participants in the present study would be highest in task self-efficacy and would have lower but similar barrier and scheduling self-efficacy. Since imagery is an important source of selfefficacy, the second aim of the study was to examine the relationship between imagery use and self-efficacy

3 Self-efficacy and imagery use 199 in older exercisers. To accomplish this, hierarchical regression analyses were conducted in which the three uses of imagery served to predict each type of selfefficacy. More specifically, for task self-efficacy, technique imagery (i.e. imaging performing exercise tasks) was entered first, followed by appearance and then energy imagery. Appearance and energy imagery were entered separately since they have been found to differentially influence other exercise variables. For example, only energy imagery predicts obligatory exercise (Rodgers, Hall, Blanchard, & Munroe, 2001), while only appearance imagery predicts intention to exercise (Rodgers, Munroe, & Hall, 2002b). For barrier self-efficacy, energy imagery was entered first, since imaging being energized should help exercisers overcome common barriers such as being too tired and unmotivated to exercise (for a discussion of exercise barriers, see Eyler et al., 1998). Appearance and technique imagery were then entered separately in that order. With respect to scheduling self-efficacy, a strong rationale for the order of entry for the uses of imagery was less evident. Since a weak argument could be forwarded that using energy imagery might increase exercisers confidence that they can effectively schedule their exercise activity, it was decided to employ the same order of entry as for barrier self-efficacy (i.e. energy, appearance, and then technique imagery). Methods Participants Male (n / 40) and female (n / 52) exercise participants aged 65 years and over (mean 74 years, s/ 7.3) were recruited from the Canadian Centre for Activity and Aging and the Retired Researchers Activity Group at a large university in Ontario, Canada. Participants took part in various exercise classes that included weight training, walking, or a combination of cardiovascular and resistance training activities. (A detailed description of the content and schedule of the exercise classes is available on the Centre for Activity and Aging website: The various exercise classes were offered 3 5 times per week and varied from 45 to 75 min in duration. Participants were recruited after the classes had been in progress for 6 weeks. Measures Exercisers use of imagery was evaluated using the Exercise Imagery Questionnaire (EIQ; Gammage et al., 2000; Hausenblas et al., 1999). The EIQ contains nine items whereby participants are asked to rate the frequency of their imagery use on a 9-point scale (1/ never to 9/ always ). The EIQ consists of three subscales appearance imagery, technique imagery, and energy imagery each of which is made up of three items. An example of an appearance imagery item is I imagine myself looking better from exercising. An example of an energy imagery item is To get me energized, I imagine exercising. Finally, an example of a technique imagery item is When thinking about exercising, I imagine my form and body position. For the purpose of the present study, three items of the EIQ were slightly reworded to better represent the sample of older adults. For example, whereas an item on the energy subscale was To take my mind off my work, I imagine exercising, the revised item used in the present study was To take my mind off other things, I imagine exercising. Participants responses were summed and divided by three to create an average value for each of the three subscales. In addition to the nine items on the EIQ, Rodgers et al. (2002a) included three additional questions: (1) How much do you think about exercising when not exercising? ; (2) When you think about exercise, do you think about the exercise itself? ; and (3) When you think about exercise, do you think about the benefits of exercise? Although they were administered in the present study, the inclusion of these three questions did not offer any additional insight; thus, they were not considered further. The EIQ has been found to be psychometrically sound; that is, confirmatory factor analysis fit indices suggest excellent model fit [root mean square error of approximation (RMSE) /0.05; adjusted goodness-of-fit index (GFI) /0.93; comparative fit index (CFI) /0.99] (Rodgers et al., 2001). Furthermore, Cronbach s alphas in previous research (Gammage et al., 2000; Hausenblas et al., 1999; Rodgers, Hall, Blanchard, & Munroe, 1999) have indicated acceptable reliabilities for the EIQ subscales (a /0.81 to a /0.86). In the present study, Cronbach s alphas were also acceptable (appearance imagery, a /0.96; energy imagery, a /0.89; technique imagery, a/0.91). Exercisers self-efficacy was evaluated using the Self-Efficacy Questionnaire for Exercisers (SEQE; Rodgers & Sullivan, 2001). The SEQE is a 23-item scale representing three types of self-efficacy: task (n /7 items), scheduling (n /8 items), and barrier (n/8 items). An example of a task self-efficacy item is How confident are you that you can exercise using proper technique? An example of a scheduling self-efficacy item is How confident are you that you can plan other activities around exercise? Finally, an example of a barrier self-efficacy item is How confident are you that you can exercise when you don t feel like it? Participants are asked to rate

4 200 N. N. Wesch et al. their self-efficacy on a 100% confidence scale ranging from 0% (indicating no confidence) to 100% (indicating complete confidence). The percentages were added and divided by the number of items in the subscale to create an average percentage for each of the three subscales. In previous research, the SEQE has been found to be both valid and reliable. Specifically, confirmatory factor analysis has supported the three factors (RMSE /0.04; GFI/0.96; CFI /0.97), and Cronbach s alphas have been acceptable (a /0.72 to a /0.88) (Rodgers & Sullivan, 2001; Rodgers et al., 2002a). In the present study, Cronbach s alpha was 0.66, 0.74, and 0.82 for task, scheduling, and barrier self-efficacy respectively. [Initially, the internal consistency for the barriers self-efficacy scale (n /8 items) was unacceptable (a /0.51). Following a statistical examination of each item on this scale, an item that appeared problematic with the present sample ( How confident are you that you can exercise when you are in a bad mood? ) was removed, resulting in an acceptable reliability (a /0.82). Thus, only seven items on the barrier self-efficacy scale were included in subsequent analyses.] In addition to the EIQ and the SEQE, participants were asked to provide demographic information including age and gender. Participants were also asked to indicate their primary type of exercise activity (walking, strength training, or other) by circling the appropriate response on the questionnaire and by providing a written response if they circled other. Procedures Ethics approval was obtained from the Office of Research Ethics at the university where the study was conducted. Participants were contacted either immediately before or just after their respective exercise classes. At this time, the participants were provided with a letter of information and a description of the study, were informed that participation was voluntary and that they could withdraw at any time, and were asked to complete the EIQ, SEQE, and demographic information described above. In total, the questionnaires took approximately 10 min to complete. Completion of the questionnaires indicated consent, and the participants returned the questionnaires immediately to the researcher. Results Descriptive statistics and preliminary analyses Descriptive statistics and simple correlations for each variable are listed in Table I. Initially, two separate multivariate analyses of variance were conducted to determine whether gender influenced either selfefficacy or imagery use. These analyses were undertaken as a result of evidence from Lirgg, George, Chase and Ferguson (1996), who found that selfefficacy can differ as a function of gender, and from Gammage et al. (2000), who reported gender differences in relation to imagery use. In the present study, no gender differences were found for either self-efficacy or imagery use (P /0.05). Thus, male and female responses were combined for all subsequent analyses. Next, a repeated-measures analysis of variance (ANOVA) was conducted to determine whether differences existed between the three SEQE subscales (task, barrier, and scheduling). Results revealed differences between all three subscales (F 2,90 /19.54, PB/0.01). Specifically, participants were most efficacious in terms of the task, followed by scheduling physical activity into their daily routines, and finally overcoming barriers related to physical activity. A second repeated-measures ANOVA was also performed to determine whether participants differed in their use of imagery. Results showed that participants reported using appearance and technique imagery to about the same extent, but used both more than energy imagery (F 2,90 /23.77, PB/0.01). It should be noted that the means for imagery use in Table I. Descriptive statistics and correlations (n/92). Variable Mean s Task self-efficacy ** 0.52** * 2. Barrier self-efficacy * 0.64** Scheduling self-efficacy * * 4. Technique imagery * 0.61** 0.65** 5. Appearance imagery * 0.68** 6. Energy imagery * Note: Task, barrier, and scheduling self-efficacy were rated on a confidence scale ranging from 0% to 100% with higher values indicating greater perceptions of self-efficacy. Technique, appearance, and energy imagery were scored on a scale of 1 to 9 with higher values indicating greater imagery use. * P B/0.05; ** P B/0.01.

5 Self-efficacy and imagery use 201 Table II. The relationship between imagery use and self-efficacy: Summary statistics for hierarchical regression analyses (n/92). Imagery subscale R R 2 R 2 change Task self-efficacy Technique /0.02 Appearance /0.10 Energy * Barrier self-efficacy Energy Appearance /0.11 Technique /0.02 Scheduling self-efficacy Energy Appearance /0.01 Technique /0.13 Note : The imagery subscales are presented in the order in which they were entered into the regression equations. * P B/0.05. the present study are similar to those reported by Milne et al. (in press) for a comparable sample of older adults. Self-efficacy and imagery use To examine the relationship between self-efficacy and imagery use, a series of three hierarchical regression analyses was conducted (see Table I for the statistics associated with these analyses). For task self-efficacy, technique imagery was entered into the regression equation followed by appearance imagery and then energy imagery. Results showed that technique imagery did not predict task self-efficacy (P /0.05), and accounted for only 2% of the variance. Appearance imagery did not account for any additional variance and was not statistically significant (P /0.05). Energy imagery accounted for an additional 5% of the variance (R 2 /7%) and was found to be a significant predictor of task selfefficacy (F 1,88 /4.40, P B/0.05). For both barrier and scheduling self-efficacy, energy imagery was entered first in the regression equation, followed by appearance imagery and technique imagery. Results revealed that all three uses of imagery failed to predict either barrier or scheduling self-efficacy (P /0.05). Interestingly, although non-significant, an examination of the standardized regression weights revealed a common trend in that energy imagery was the strongest predictor of both barrier (b /0.21, P /0.19) and scheduling (b /0.25, P /0.11) self-efficacy. Discussion Three different types of self-efficacy have been considered in the exercise psychology literature: b task, barrier, and scheduling (DuCharme & Brawley, 1995; Rodgers et al., 2002a; Rodgers & Sullivan, 2001). Since these three types of self-efficacy have yet to be assessed in an older adult population, one aim of the present study was to measure these types of self-efficacy in a sample of older exercisers (65/ years of age). Based on previous research with younger exercisers (Rodgers & Sullivan, 2001), it was hypothesized that participants would be highest in task self-efficacy and would have less but similar barrier and scheduling self-efficacy. A slightly different pattern of results emerged than hypothesized. As expected given the participants were all exercisers in classes that had been ongoing for 6 weeks, they were most efficacious in terms of the task (i.e. they were quite confident they could do the exercises). However, they were higher in scheduling than barrier selfefficacy. This finding should not be that surprising, since these older exercisers probably would be quite flexible in scheduling their exercise sessions compared with their younger counterparts who would have more scheduling constraints (e.g. work, looking after young children). With respect to barriers, both older and younger exercisers would face barriers, although perhaps different ones (e.g. health issues versus time constraints), and the confidence in their ability to exercise despite these barriers will usually be somewhat of a challenge (Rodgers & Sullivan, 2001). With respect to imagery use, a slightly different pattern of results was found in the present study than previously reported. Milne et al. (in press) found that older adults employed appearance imagery the most, followed by technique and then energy imagery. In the present study, exercisers used appearance and technique imagery to about the same extent, and used energy imagery the least. Research (Gammage et al., 2000; Rodgers et al., 2001) has consistently shown that young exercisers use appearance imagery the most, possibly reflecting a strong appearance motive for exercising. Although appearance seems to be an important motive for older adults to exercise, older people tend to be more satisfied with their appearance than younger individuals (Hetherington & Burnett, 1994; Pliner, Chaiken, & Flett, 1990). Thus, it follows that older exercisers would use less appearance imagery than younger exercisers and this has been shown to be the case (Milne et al., in press). However, why older exercisers in the present study reported using less appearance imagery (mean/5.35) than those in study of the Milne et al. (mean/6.15) is not clear. A second aim of the present study was to examine the relationship between imagery use and selfefficacy in older exercisers. Results revealed that contrary to what was expected, technique imagery did not predict task self-efficacy. This is surprising

6 202 N. N. Wesch et al. considering the fact that both variables are associated primarily with the task aspect(s) of an activity. One explanation for this finding is that technique imagery entails visualizing the proper performance of the exercise movements, and after 6 weeks of classes the participants were likely already very familiar with these movements. Therefore, at this point in time technique imagery would probably have little influence on participants self-efficacy for performing these movements. Results also revealed that appearance imagery did not predict task self-efficacy, whereas energy imagery was a significant predictor. The lack of a correspondence between the use of appearance imagery and task self-efficacy was expected since appearance imagery serves primarily a motivational rather than a cognitive function (Hausenblas et al., 1999). Although the link between energy imagery and task self-efficacy is also not readily apparent, previous research (e.g. Giacobbi, Hausenblas, Fallon, & Hall, 2003) has suggested that exercisers have expressed the need to get psyched up or energized before exercising. Furthermore, Rodgers et al. (2001) demonstrated that despite high ratings of appearance imagery relative to technique and energy imagery, energy imagery emerged as the strongest predictor of obligatory exercise behaviour. Thus, the present results further emphasize the importance of energy imagery in relation to exercise behaviour in that, although the use of energy imagery was lower than the use of appearance or technique imagery, visualizing feelings of being energized or psyched up was the strongest predictor of individuals confidence in their ability to physically engage in exercise. It was also hypothesized that imaging being energized should help exercisers overcome common barriers such as being too tired and unmotivated to exercise. In contrast to this hypothesis, the use of energy imagery failed to predict barrier self-efficacy and also failed to predict scheduling self-efficacy. This is somewhat perplexing considering that lack of energy has been found to be the main barrier to exercise for adults over 65 years of age (Canadian Fitness and Lifestyle Research Institute, 1996a). Of course, lack of energy is just one barrier and is one that is likely to dissipate the more people exercise (i.e. regular exercise increases energy levels). However, it is possible that the other types of barriers that energy imagery might help exercisers overcome are not the ones that present the greatest challenges to older exercisers. Research has found that the other commonly reported barriers by older exercisers include health, environmental, and ecological factors (Canadian Fitness and Lifestyle Research Institute, 1996a). Confidence to overcome these types of barriers is less likely to be influenced by the use of energy imagery. The present study is not without its limitations. First, the sample of older exercisers used in the present study is not representative of the general population of older adults considering that less than one in four individuals over the age of 65 are physically active (Canadian Fitness and Lifestyle Research Institute, 1996b). Also, because mastery experiences have been identified as a strong determinant of self-efficacy (Bandura, 1997), a second limitation associated with the present study is the failure to control for participants exercise experience. Since the present study has demonstrated that older adults differ in the three types of self-efficacy (i.e. task, barrier, and scheduling), future research with this population should consider all three types of self-efficacy when examining exercise intention and behaviour. While McAuley et al. (2003) found that self-efficacy increases the long-term exercise participation of older adults, it is likely that task, barrier, and scheduling self-efficacy have differential effects on this involvement. Since the present results also revealed that energy imagery predicted task selfefficacy, the use of energy imagery may be an effective intervention that can be used to enhance older adults confidence in their ability to exercise. Researchers should design and implement interventions with a primary emphasis on energy imagery with the aim of increasing task self-efficacy and, ultimately, exercise participation rates among older adults. Overall, the results of the present study show that older adults are quite efficacious in terms of: (a) the task, (b) scheduling physical activity into their daily routines, and (c) overcoming barriers related to physical activity. Older adults also appear to use all three types of exercise imagery, and the use of energy imagery significantly predicts task self-efficacy. These findings suggest that additional research investigating the three types of self-efficacy and imagery in older exercisers would likely be worthwhile. A better understanding of self-efficacy and imagery could potentially assist practitioners in their attempts to encourage older adults to become more physically active. Acknowledgements Special thanks to the staff and participants at the Canadian Centre for Activity and Aging and the Retired Researchers Activity Group, both located in London, Ontario.

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