Journal of Physical Activity and Health, 2014, 11, 801-809 http://dx.doi.org/10.1123/jpah.2012-0060 © 2014 Human Kinetics, Inc.
Official Journal of ISPAH www.JPAH-Journal.com ORIGINAL RESEARCH
Associations Between Perceived Health Benefits and Barriers to Strength Training, and Stages of Change for Strength-Training Behavior Among Older Japanese Adults Kazuhiro Harada, Ai Shibata, Euna Lee, Koichiro Oka, and Yoshio Nakamura Background: Although several studies have examined associations of perceived benefits and barriers with physical activity, no studies have focused on them corresponding to strength-training recommendations for older adults. This study examined the associations among the perceived health benefits of strength training, perceived barriers to strength straining, and stages of change for strength-training behavior in older Japanese adults. Methods: This cross-sectional survey included a random sample of 1144 adults (60–74 years) from the city of Tokorozawa. Stage of change was the independent variable, with perceived health benefits (eg, strength training can reduce body pain) and perceived barriers (eg, facilities are needed for strength training) as dependent variables. Data were analyzed by analysis of covariance and Bonferroni’s multiple comparison. Results: After adjusting for demographic variables, the perceived health-benefit score for precontemplation was significantly lower than for the other four stages. The perceived barrier scores in the precontemplation and contemplation stages were significantly higher than those in the preparation and maintenance stages. Conclusions: These results suggest that information about the health benefits for older adults and about the recommended type of strength training might be useful for the development of strategies to promote strength training among older adults. Keywords: resistance training, motivation, exercise psychology, gerontology, health promotion Current physical activity guidelines, such as the 2008 Physical Activity Guidelines for Americans published by the U.S. Department of Health and Human Services (USDHHS)1 and the 2006 Japanese exercise guidelines issued by the Japan Ministry of Health, Labor, and Welfare (JMHLW)2 recommend strength training for health promotion. Promoting strength training is thus a public health priority. The current recommendations include 2 notable points. First, strength training is recommended for older adults,1,3 as well as for adults in general; since the 1990s, numerous studies have indicated that strength training can reduce the risk of some geriatric problems such as sarcopenia and loss of bone density,4,5 as well as having general health benefits such as reducing the risk of cardiovascular disease and type 2 diabetes.6 In particular, JMHLW emphasizes the benefits of strength training for reducing knee and lower-back pain, as well as risks of bone fractures and falls.3 Second, exercises that do not require any special facilities, equipment, or demonstrations are also recommended for strength training.1,2 For example, in addition to weight-machine training, the USDHHS recommends push-ups, squats, climbing stairs, carrying heavy loads, and heavy gardening for strengthening muscles.1 Nevertheless, older adults are less likely to participate in strength training than younger adults.7,8 According to the impact levels of mass communication campaigns for promoting physical activity,9 disseminating information regarding these current strength-training recommendations (health benefits for older adults, recommended Harada is with the Section for Motor Function Activation, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan. Shibata is with the Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan. Lee, Oka, and Nakamura are with the Faculty of Sport Siences, Waseda University, Tokorozawa, Saitama, Japan.
type of strength training) represents the first important step in promoting strength training in older adults. The identification of modifiable factors associated with physical activity is recognized as an essential phase in the development of effective promotion strategies.10 In addition, the Transtheoretical Model suggests that identifying factors associated with not only actual behavior, but also with intention or motivational readiness, are important for developing more effective promotion of physical activity.11 The central construct of this Transtheoretical Model has been suggested as a favorable framework for understanding both behavior and intention as stages of change.12 Examining the associations between perceived health benefits and barriers, and the stages of change for strength-training behavior would be helpful for investigating if information about current strength-training recommendations is useful for developing strength-training-promotion strategies among older adults. Perceived benefits and barriers are widely used for examining correlates of physical activity13–19 and are key concepts of the health belief model.20 Similar concepts are included in other major psychological theories, such as pros and cons in the Transtheoretical Model,12 and behavioral and control beliefs in the theory of planned behavior.21 If positive associations with perceived health benefits with the stages of change for strengthtraining behavior are observed, it might indicate that information about the health effects in older adults could be useful to promote strength training. With regard to the type of strength training, inconsistent perception of the current recommendations (ie, strength training requires a special facility or equipment) can be regarded as a perceived barrier to strength training, and similar perceptions have been included in the perceived barriers to physical activity.13–19,22–24 If such perceived barriers are negatively associated with stages of change for strength-training behavior, it suggests that information about the recommended type of strength training might be useful 801
802 Harada et al
in developing strategies to promote strength training. Although several studies have analyzed the perceived benefits and barriers to physical activity,13–19 only two have examined their relationships with strength training, either among college students16 or among older women.19 No studies have measured the perceived benefits and barriers corresponding to strength-training recommendations in older adults. The population of frail, older adults has increased dramatically in Japan. The fact that these individuals lose their independence more quickly if they do not maintain their muscle strength has been recognized as an important issue for the health system. The current study, therefore, examined the associations among perceived health benefits of strength training, perceived barriers to strength training, and stage of change for strength-training behavior among older Japanese adults.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Methods Participants and Procedures A cross-sectional questionnaire was distributed through the postal mail to 2092 individuals aged 60–74 years living in Tokorozawa city (population: 341,679; area: 72.0 km2), a typical suburb near Tokyo. A stratified, systematic random method was used to select residential addresses from the city registry. Stratification was performed according to agricultural promotion area (APA). An APA is defined as the area where land use is limited to agriculture by law (the use for other purposes is prohibited in APA), and APAs can thus roughly be regarded as rural areas. The city consists of 11 districts; 3 districts did not include an APA (group A), 5 districts included APAs that were < 50% of the total area (group B), and 3 districts included APAs that were > 50% of the total area (group C). One district was randomly selected from each group. The total population aged 60–74 years in the 3 selected districts was about 12,400. Every sixth person was selected as a participant, according to the order of residential addresses. The survey was conducted in November and December 2009.Twelve of the 2092 individuals did not receive the questionnaire because their addresses were incorrect. A total of 1,288 of the remaining 2080 individuals (61.9%) responded to the questionnaire. Book coupons worth ¥500 were provided as incentives for respondents to the survey. Among these, 33 did not answer the questions for the following reasons: no interest in the survey (n = 14), difficulty in writing or reading (n = 6), lack of time (n = 5), absence of respondent (n = 4), or other (n = 4). A total of 1244 individuals who answered the question about stage of change for strength training behavior (11 individuals had missing data for this question) were included in the analysis (59.8%). A paper explaining the ethical considerations was enclosed with the questionnaire. Individuals were asked to answer and reply to the questionnaire anonymously, only if they understood the ethical considerations and agreed to participate. Return of the questionnaire thus indicated informed consent. This study received prior approval from the Waseda University Ethics Committee (2009-108).
Measurements Stages of Change for Strength Training Behavior. Based on previous studies8,25,26 and the definition provided in the current recommendations,1,2 strength training was defined as all exercise that serves to enhance muscular strength and endurance; regular strength training was regarded as exercise on 2 or more days per week.
The stage-of-change scale for strength-training behaviors8 was employed. This scale consists of 5 choices: precontemplation (not engaged in regular strength training and not intending to engage within the next 6 months), contemplation (intending to engage in strength training within the next 6 months), preparation (engaged in strength training irregularly), action (engaged in regular strength training but for less than 6 months), and maintenance (engaged in regular strength training for the past 6 months or more). Respondents were asked to choose one stage that best described their current condition. Perceived Health Benefits of Strength Training. In the revised
program manual for the improvement of motor function for prevention of long-term care, JMHLW focused on the reduction of body pain (knee and lower back), risk of bone fracture, and risk of falls with regard to the health benefits of strength training for older adults.3 A new scale was developed based on this manual and the existing perceived-benefits scale.13–19 The items were “strength training can enhance muscular strength, even at age 65,” “strength training can enhance muscular strength, even at age 75,” “strength training can enhance muscular strength, even at age 85,” “strength training can reduce body pain,” “strength training can reduce the risk of bone fracture,” “strength training can reduce the risk of fall,” and “strength training can reduce the risk of long-term care need.” These items were evaluated using a 4-point Likert scale: “strongly disagree” (1), “somewhat disagree” (2), “somewhat agree” (3), and “strongly agree” (4). Perceived Barriers to Strength Training. A new scale for perceived barriers to strength training was developed based on a previous qualitative study about perceptions of strength training,27 the existing perceived-barrier scale,13–19,22–24 and the current strengthtraining recommendations.1,2 The items were “strength training is susceptible to injury,” “a facility is necessary for strength training,” “strength training can be done at home,” “instruction is necessary for strength training,” “equipment is necessary for strength training,” “strength training is hard work,” and “strength training is exercise for athletes.” As with the benefits scale, a 4-point Likert scale was used. Demographic Variables. Demographic variables were measured
using the same questionnaire. Variables included age, gender (male; female), self-rated health status (very good; somewhat good; somewhat poor; very poor), number of hospital visits (more than once a week; once or twice a month; once every 2 or 3 months; less than once every 6 months), restriction of physical activity by medical professionals (yes; no), body pain (no; slight; light; moderate; severe; very severe), marital status (currently married; divorced or bereaved; single), smoking habit (current smoker; previous smoker; never smoker), and drinking habit (3 days or more per week; less than 3 days per week; no). For convenient analysis and/or to accommodate small sample sizes in some categories, some demographic variables were collapsed as follows: self-rated health status (good or poor), number of hospital visits (more than once a month or not), body pain (more than moderate pain or not), current marital status (yes or no), current smoking habit (yes or no), current drinking habit (more than 3 days per week or not).
Analyses Regarding missing data for the perceived health benefits and barriers scales, the mean value for the total participants was used if there was one missing item in the scale. If the scale included two or more missing items, the data were excluded from subsequent analyses.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Perceived Benefits and Barriers to Strength Training 803
Confirmatory factor analyses were conducted to identify the construct validities of the perceived health benefits and barriers scales. Regarding floor or ceiling effects, items for which more than 50% of respondents answered “strongly disagree” or “strongly agree” were excluded from the analyses. The models assumed onefactor structure. Goodness of fit index (GFI), comparative fit index (CFI), and root mean square error of approximation (RMSEA) were calculated. If the indexes were not acceptable (GFI or CFI < 0.90, RMSEA < 0.10) or path coefficients were < 0.40, the modified model was examined. Cronbach’s alpha of the scale was calculated. The scores for each item were summarized. Associations between each demographic variable and stage of change for strength-training behavior were analyzed by χ2 tests. Analysis of covariance was used to examine the relationships between stage of change for strength-training behavior and perceived health benefits and barriers. The independent variable was the stage of change and the dependent variables were the scores for the perceived health benefits and the perceived barriers. The covariates were demographic variables that were significantly associated with stage of change according to the χ2 results. Bonferroni’s method was used for post hoc analysis.
Analyses of covariance stratified by gender were also conducted, and associations between each item of the perceived health benefits and barriers scales, and the stages of change were examined. Statistical significance was set at P < .05. All statistical analyses were conducted using SPSS (version 15.0) and AMOS (version 16.0) software packages.
Results Characteristics of the Respondents Table 1 shows the characteristics of the respondents: 51.5% were men (age, 66.5 [SD 4.5] years), and 48.5% were women (age, 66.1 [SD 4.1] years). For all respondents, 84.5% reported good health, 60.0% visited the hospital less than once a month, 93.5% did not restrict their engagement in physical activity because of the advice of medical professionals, 74.6% did not have more than moderate body pain, 85.7% were married, 83.6% did not have a smoking habit, and 67.8% consumed alcohol on 3 or more days per week.
Table 1 Associations Between Demographic Variables and Stage of Change for Strength-Training Behavior Stage of change for strength-training behavior (%) Total Age (years) < 65 65–69 ≥ 70 Gender Male Female Self-rated health status Poor Good Hospital visit < once a month ≥ once a month Restriction of physical activity by medical professionals No Yes Body pain No Yes Marital status Unmarried Married Smoking habit No Yes Drinking habit No Yes
Total (n)
PC (n = 374)
C (n = 279)
PR (n = 281)
A (n = 51)
M (n = 259)
1244
30.1
22.4
22.6
4.1
20.8
480 429 329
29.2 27.7 34.7
24.8 22.6 19.1
20.2 24.5 23.1
6.0 4.0 1.5
19.8 21.2 21.6
638 600
31.2 29.0
21.9 23.2
21.9 23.0
4.5 3.7
20.4 21.2
191 1045
39.3 28.5
24.1 22.2
17.8 23.3
4.7 4.0
14.1 21.9
742 494
29.6 31.0
22.9 21.9
23.0 21.7
4.2 4.0
20.2 21.5
1157 78
29.5 39.7
23.2 14.1
22.6 20.5
4.0 6.4
20.8 19.2
924 314
30.2 29.9
20.1 29.6
22.8 21.3
3.7 5.4
23.2 13.7
177 1059
36.7 29.1
26.6 21.9
17.5 23.2
2.8 4.3
16.4 21.4
1036 203
28.0 40.9
22.1 24.6
22.9 20.7
4.3 3.0
22.7 10.8
839 399
28.6 33.3
22.9 21.6
22.9 21.8
4.2 4.0
21.5 19.3
P value† .021
.822
.009
.938
.165
< .001
.054
< .001
.561
Note. Sample sizes vary because of missing values. Abbreviations: PC, precontemplation; C, contemplation; PR, preparation; A, action; M, maintenance. † χ2 tests.
804 Harada et al
Factor Structure and Internal Consistency for Perceived Health Benefits of Strength Training
= 0.993, CFI = 0.992, and RMSEA = 0.049. Cronbach’s alpha of this model was .78 (Table 3).
The distributions of each item are summarized in Table 2. Confirmatory factor analysis that included all items was conducted initially (initial model). The indexes of this model were poor (GFI = 0.731, CFI = 0.684, RMSEA = 0.270). Correlations were relatively higher among “strength training can enhance muscular strength, even at age 65,” “strength training can enhance muscular strength, even at age 75,” and “strength training can enhance muscular strength, even at age 85” (r = .57–.79). Therefore, “strength training can enhance muscular strength, even at age 65” and “strength training can enhance muscular strength, even at age 85” were excluded because the coefficient for “strength training can enhance muscular strength, even at age 75” was the highest among these 3 items. The indexes of the modified model were GFI
Factor Structure and Internal Consistency for Perceived Barriers to Strength Training Because more than half the participants answered “strongly disagree” to the questions “strength training is susceptible to injury” (50.5%) and “strength training is exercise for athletes” (53.8%), these items were excluded from factor analysis. In the initial model including 5 items, the goodness-of-fit indexes were acceptable: GFI = 0.983, CFI = 0.957, RMSEA = 0.086. However, the coefficient was < 0.40 for “strength training can be done in the home” (–0.392) and a modified model was therefore created that excluded this item. The indexes of the modified model were GFI = 0.999, CFI = 0.999, RMSEA = 0.018 (Table 3). Cronbach’s alpha of this model was .71.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Table 2 Distribution of Items in the Perceived Health Benefits and Barriers Scales n
Strongly disagree (%)
Somewhat disagree (%)
Somewhat agree (%)
Strongly agree (%)
1181
0.8
9.8
46.2
43.2
Perceived health benefits of strength training Strength training can enhance muscular strength, even at age 65 Strength training can enhance muscular strength, even at age 75
1159
3.6
25.6
46.2
24.6
Strength training can enhance muscular strength, even at age 85
1148
13.4
40.3
31.7
14.5
Strength training can reduce body pain
1176
3.0
19.6
53.3
24.1
Strength training can reduce the risk of bone fracture
1169
2.7
16.4
46.4
34.5
Strength training can reduce the risk of fall
1169
2.1
8.0
45.0
44.9
Strength training can reduce the risk of long-term care need
1178
2.9
9.6
45.4
42.1
1155
50.5
38.8
9.9
0.9
A facility is necessary for strength training
1157
44.3
33.6
16.2
6.0
Strength training can be done at home
1201
6.5
10.7
38.5
44.3
Perceived barriers to strength training Strength training is susceptible to injury
Instruction is necessary for strength training
1169
7.7
20.3
52.6
19.4
Equipment is necessary for strength training
1153
17.2
37.4
33.7
11.8
Strength training is hard work
1152
9.3
33.6
43.2
13.9
Strength training is an exercise for athletes
1158
53.8
31.7
8.8
5.7
Table 3 Factor Structure in the Scales of Perceived Health Benefits of Strength Training and Perceived Barriers to Strength Training Scale
Coefficient
Perceived health benefits of strength training (GFI = 0.993, CFI = 0.992, RMSEA = 0.049, α = .78) Strength training can enhance muscular strength, even at age 75 Strength training can reduce body pain Strength training can reduce the risk of bone fracture Strength training can reduce the risk of fall Strength training can reduce the risk of long-term care need
0.41 0.55 0.79 0.82 0.67
Perceived barriers to strength training (GFI = 0.999, CFI = 0.999, RMSEA = 0.018, α = .71) A facility is necessary for strength training Instruction is necessary for strength training Equipment is necessary for strength training
0.69 0.52 0.74
Strength training is hard work
0.52
Perceived Benefits and Barriers to Strength Training 805
Associations Between Demographic Variables and Stage of Change Table 1 shows the associations between demographic variables and stage of change. Of all respondents, 30.1% were in the precontemplation stage, 22.4% were in the contemplation stage, 22.6% were in the preparation stage, 4.1% were in the action stage, and 20.8% were in the maintenance stage. Significant associations with stage of change for strength-training behavior were revealed for age, selfreported health status, body pain, and smoking habits. Those in the action stage were likely to be younger. Poor health status, presence of body pain, and smoking habit were negatively associated with stage of change for strength-training behavior.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Associations Between Stage of Change and Perceived Health Benefits and Barriers After adjusting for demographic variables (age, self-reported health status, body pain, and smoking habits), higher perceived health benefits (F = 23.34, P < .0001, η2 = 0.075) and lower perceived barriers (F = 19.70, P < .0001, η2 = 0.064) were significantly associated with higher stages of change (Figures 1 and 2). In a post hoc analysis, the score for perceived health benefits in the precontemplation stage was significantly lower than that in the other four stages. In addition, the score in the contemplation stage was significantly lower than that in the maintenance stage. There were no significant differences among the scores in later stages (preparation, action, maintenance). Regarding the perceived barriers scale, the scores in the precontemplation and contemplation stages were significantly higher than those in the preparation and maintenance stages. There were
no significant differences in scores among the preparation, action, and maintenance stages. Regarding the results of the additional analyses (Table 4), significant associations between perceived health benefits and barriers, and stages of change were observed in both men (perceived health benefits, F = 11.86, P < .001, η2 = 0.080; perceived barriers, F = 8.97, P < .001, η2 = 0.060) and women (perceived health benefits, F = 11.86, P < .001, η2 = 0.080; perceived barriers, F = 8.97, P < .001, η2 = 0.060). Similarly, all perceived health benefits and barriers scale items were significantly associated with the stages of change (Table 5).
Discussion To the best of our best knowledge, this represents the first study to measure perceived benefits and barriers in relation to current strength-training recommendations for older adults. Although previous studies measured various aspects of perceived benefits and barriers,13–19 they were unsuitable for exploring the usefulness of information about the current recommendations (benefits for older adults, types of strength training) in terms of developing promotion strategies for strength training among older adults. Moreover, few studies have examined the correlates of strength-training behavior among older adults,19,25,26 even though this is essential for developing effective promotion strategies.10 The major finding of this study was that both perceived health benefits and barriers to strength training were associated with the stage-of-change scale for strength training among older Japanese adults. Moreover, additional analyses indicated that all perceived
Figure 1 — Associations between the perceived health benefits of strength training and stage of change for strength-training behavior. The score of perceived health benefits was adjusted for age, self-reported health status, body pain, and smoking habits. * P < .05; ** P < .01; *** P < .001.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
806 Harada et al
Figure 2 — Associations between the perceived barriers to strength training and stage of change for strengthtraining behavior. The score of perceived barriers was adjusted for age, self-reported health status, body pain, and smoking habits. * P < .05; ** P < .01; *** P < .001.
health benefits and barriers scale items were significantly associated with the stages of change. These results suggest that information about health benefits for older adults and about the recommended type of strength training might be useful for the development of strategies to promote strength training among older adults. Additional analyses also revealed associations between the perceived health benefits and barriers, and the stages of change in both men and women. A previous study19 revealed significant associations between decisional balance (pros-cons: similar concept to perceived benefits and perceived barriers), and strength-training behavior among older adults; however, this previous study only targeted women.19 The current study thus expanded these findings to demonstrate that the associations were irrespective of gender. Post hoc analysis showed that older adults in the precontemplation stage were less likely to perceive the health benefits compared with those in the other four stages. In contrast, among the other four stages, a significant difference in perceived health benefits was revealed only between the contemplation and maintenance stages. These results indicate that perceived health benefits are especially associated with the transition from the precontemplation to the contemplation stage. A previous study in college students revealed significant differences in pros-scale scores for strength training between the precontemplation and higher stages.16 Likewise, a review of physical activity correlates showed that knowledge of health benefits was not directly associated with physical activity.28 Rudd and Glanz29 mentioned that, although knowledge was required for making health-related decisions, it might not be sufficient to change behaviors. Another study identified awareness of the role of exercise in cancer prevention as positively affecting exercise motivation but not maintenance of exercise.30 The perceived health benefits of strength training among older adults might therefore be associated with intention, rather than with strength-training behavior itself.
Although the differences between the action and other stages were not clear, those who did not engage in strength training (precontemplation and contemplation stages) tended to perceive barriers more strongly than those who did engage in strength training (preparation and maintenance stages). Thus, perceived barriers to strength training would inhibit its initiation (ie, the transition from contemplation to preparation or action stages). Some studies found no significant relationship between the perceived barriers (or cons) and the stage-of-change scale for strength training16 and exercise behavior,13 while other studies reported differences in the scores for perceived barriers among college students18 and employees,15 especially between the contemplation and preparation stages for exercise behavior. However, some perceived barriers measured in previous studies,13–19,22–24 such as lack of money or time, would not be easy to modify. However, because current guidelines1,2 recommend types of strength training that do not require special facilities, equipment, or instructions, the perceived barriers measured in the current study could be reduced by providing older adults with information about the recommended types of strength training. There were no significant differences in perceived health benefits and barriers among the preparation, action, and maintenance stages, suggesting that the perceived health benefits and barriers might not be important in terms of developing strategies to reinforce and maintain strength-training behavior among older adults. Previous studies examining the associations between perceived benefits and barriers (or pros and cons) with stage-of-change scales for exercise behavior13,15,18 or strength-training behavior16 also failed to reveal significant differences among the later stages. Theoretically, feelings of self-efficacy to overcome perceived barriers, as well as a perception of the threats and benefits, are needed to initiate and maintain health behaviors requiring long-term changes (eg, physical activity, healthy diet).31 Indeed, physical-activity studies found that self-efficacy was a key factor in the maintenance of behavior
807
0.19 0.21 0.18 0.19
14.05 15.10
10.37 10.51
SE†
10.38 9.68
15.39 15.93
M†
C
0.22 0.21
0.23 0.23
SE†
9.05 9.16
15.50 16.45
M†
P
0.22 0.21
0.22 0.23
SE†
9.65 9.30
15.90 16.25
M†
A
0.47 0.52
0.48 0.57
SE†
9.16 8.49
15.88 17.39
M†
M
0.23 0.22
0.24 0.24
SE†
8.97 13.11
11.86 13.31
F value
< .001 < .001
< .001 < .001
P
0.060 0.098
0.080 0.099
η2
PC,C < P,M PC < C,P,M; C < M
PC < C,P,A,M; C < M PC < P,M; C < M
Post hoc analysis
Analysis of covariance
0.04 0.04
2.60 2.83
0.04
3.07
0.04
0.04
3.12
2.89
0.04
2.95
0.04
0.04
2.76
2.08
0.04
SE
2.73
PC
2.48 2.71
2.90
1.93
3.35
3.34
3.12
3.00
2.88
M
C
0.05 0.05
0.05
0.05
0.04
0.04
0.04
0.04
0.05
SE
2.22 2.54
2.79
1.61
3.33
3.40
3.20
3.06
2.97
M
P
0.05 0.05
0.05
0.05
0.04
0.04
0.04
0.04
0.05
SE
2.40 2.42
3.02
1.70
3.24
3.37
3.17
3.10
3.15
M
A
0.12 0.11
0.11
0.12
0.10
0.09
0.10
0.10
0.11
SE
2.21 2.31
2.71
1.64
3.41
3.54
3.32
3.20
3.13
M
M
Abbreviations: PC, precontemplation; C, contemplation; PR, preparation; A, action; M, maintenance; M, Mean; SE, Standard error. † Adjusted for age, self-reported health status, body pain, and smoking habits.
Items of perceived barriers A facility is necessary for strength training Instruction is necessary for strength training Equipment is necessary for strength training Strength training is hard work
Items of perceived health benefits Strength training can enhance muscular strength, even at age 75 Strength training can reduce body pain Strength training can reduce the risk of bone fracture Strength training can reduce the risk of fall Strength training can reduce the risk of long-term care need
M
0.05 0.05
0.05
0.05
0.05
0.04
0.05
0.04
0.05
SE
11.48 19.90
3.28
16.60
6.51
15.54
10.20
15.77
11.92
F value
< .001 < .001
.011
< .001
< .001
< .001
< .001
< .001
0.036 0.058
0.010
0.051
0.035
0.051
0.033
0.051
0.039
η2
PC,C < P,M PC < P,A,M; C < M
PC < P,A,M; C < P,M
PC < C,P,M; C < M
PC < C,P,M; C < M
PC < C,P,A,M; C < M
PC < P,A,M; C < M
PC < P,A,M; C < M
Post hoc analysis
Analysis of covariance
< .001
P
Table 5 Associations Between Each Item of Perceived Health Benefits and Barriers to Strength Training, and Stages of Change for StrengthTraining Behavior
Abbreviations: PC, precontemplation; C, contemplation; PR, preparation; A, action; M, maintenance, M, Mean; SE, Standard error. † Adjusted for age, self-reported health status, body pain, and smoking habits.
Perceived health benefits Men Women Perceived barriers Men Women
M†
PC
Table 4 Associations Between Perceived Health Benefits and Barriers to Strength Training, and Stages of Change for Strength-Training Behavior Stratified by Gender
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
808 Harada et al
among older adults.32,33 In addition, strength-training studies8,16 indicated that strength training self-efficacy would be an important factor in the transition from preparation/action to maintenance stages for strength training. Thus, approaches such as enhancing self-efficacy might be effective for reinforcing and maintaining strength-training behavior. This study was intended to explore if information about the current recommendations was effective in promoting strength training. The perceived benefits and barriers scales were therefore based on the JMHLW program manual3 and other physical activity recommendations.1,2 Thus, each scale consisted of a one-factor structure, and was not designed to measure other aspects of benefits and barriers (eg, social and psychological). Other scales with several factors, such as the Benefits and Barriers to Exercise Questionnaire,34 would be more appropriate for measuring other aspects of benefits and barriers. The current study had several limitations. First, the analysis was cross-sectional and it was therefore not possible to determine cause and effect. Second, response bias exists in questionnaire surveys; however, our response rate was not low (60%) compared with other questionnaire-based surveys using the postal mailing method, such as 51.6% in Kamada et al35 and 36.5% in Inoue et al.36 In addition, the document provided with the survey stated that the purpose of the survey was to evaluate beliefs regarding strength training among older adults. Those who were not interested in strength training would therefore be less likely to answer the questionnaire. In a previous survey in which this information was not provided, the rate of precontemplation among those > 50 years old was 47%,8 compared with 30% in the current study. In addition, answers to the questionnaire might have been influenced by social desirability and random responses. Moreover, individuals with cognitive impairment would not be able to answer the questionnaire, and it is possible that family members of sampled individuals answered the questionnaire by proxy. Third, despite acceptable internal consistencies and good construct validities, test-retest reliabilities were unclear for the scale of the perceived health benefits and barriers. Further studies are therefore required to confirm the test-retest reliabilities of the scale and to examine causal relationships from a representative sample in which response bias was eliminated. In addition, respondents might have had inaccurate self-perceptions of self-rated health status. Fourth, additional covariates, such as current physical activity level, body mass index, and socioeconomic status should also be incorporated into the survey. The study was also limited by the fact that data were only obtained from one city, which was located in a typical suburban area of Japan. It is therefore unclear if the study findings could be generalized to other populations, such as those in urban or rural areas. It is also possible that the results of this study may not be generalizable to adults of different ethnic backgrounds or from different cultures. The practical implications of the results suggest that disseminating information about the beneficial effects emphasized by JMHLW3 might be useful for increasing the intention of older adults to undergo strength training. In addition, in accordance with current physical activity guidelines,1,2 providing information that push-ups, squats, climbing stairs, carrying heavy loads, and heavy gardening constitute recommended strength-training activities might effectively encourage the initiation of strength training among older adults. Health communication strategies are recognized to useful framework to increase the intended audience’s knowledge and awareness of health issues, problems, and solutions.37 Such communication strategies would be therefore effective to plan and implement the dissemination of information on the health benefits and recommended types of strength training.
Conclusions Perceived health benefits and barriers to strength training are associated with stage-of-change scales for strength training among older Japanese adults. This suggests that information about health benefits for older adults and about the recommended type of strength training might be useful for the development of promotion strategies aimed at strength training among older adults. Acknowledgments We wish to thank Hiroshi Kono (Faculty of Human Life Design, Toyo University), Kyota Takami (Faculty of Sports and Health Sciences, Hosei University), Shinpei Okada (Physical Education and Medicine Research Foundation), Yuko Kai (Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare), Masamitsu Kamada (Japan Society for the Promotion of Science), and Soeko Sakurai (alumna of Graduate School of Sport Sciences, Waseda University) for helpful comments in the design of the current study. This work was supported by a Grant-in-Aid for Research Fellow of the Japan Society for the Promotion of Science (08J0633, 11J07878); Waseda University Grant for Special Research Projects (2010A-093); and Global COE Program ‘Sport Sciences for the Promotion of Active Life’ from the Japan Ministry of Education, Culture, Sports, Science, and Technology.
References 1. United States Department of Health and Human Services. 2008 Physical Activity Guidelines for Americans. U.S. Department of Health and Human Services. http://www.health.gov/paguidelines/pdf/paguide. pdf. Accessed July 26, 2011. 2. Japan Ministry of Health. Labour and Welfare: Kenkou zukuri no tame no undou shishin 2006. [Exercise and physical activity guide for health promotion 2006]. Japan Ministry of Health, Labour and Welfare. http://www.nih.go.jp/eiken/programs/pdf/exercise_guide. pdf. Accessed July 26, 2011. 3. Japan Ministry of Health. Labour and Welfare: Undouki no kinou koujou manyuaru. [Revised manual for the improvement of motor function]. Japan Ministry of Health, Labour and Welfare. http:// www.mhlw.go.jp/topics/2009/05/dl/tp0501-1d.pdf. Accessed July 26, 2011. 4. Chodzko-Zajko WJ, Proctor DN, Fiatarone SMA, et al. American College of Sports Medicine position stand: exercise and physical activity for older adults. Med Sci Sports Exerc. 2009;41(7):1510–1530. PubMed doi:10.1249/MSS.0b013e3181a0c95c 5. Hurley BF, Roth SM. Strength training in the elderly. Sports Med. 2000;30(4):249–268. PubMed doi:10.2165/00007256-20003004000002 6. Williams MA, Haskell WL, Ades PA, et al. Resistance exercise in individuals with and without cardiovascular disease: 2007 update: a scientific statement from the American Heart Association Council on Clinical Cardiology and Council on Nutrition, Physical Activity, and Metabolism. Circulation. 2007;116(5):572–584. PubMed doi:10.1161/ CIRCULATIONAHA.107.185214 7. Chevan J. Demographic determinants of participation in strength training activities among U.S. adults. J Strength Cond Res. 2008;22(2):553–558. PubMed doi:10.1519/JSC.0b013e3181636bee 8. Harada K, Oka K, Shibata A, Ota A, Okada J, Nakamura Y. Factors associated with stages of change for strength training behavior. Int J Sport Health Sci. 2008;6:251–263. doi:10.5432/ijshs.IJSHS20070313 9. Cavill N, Bauman A. Changing the way people think about healthenhancing physical activity: do mass media campaigns have a role?
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Perceived Benefits and Barriers to Strength Training 809 J Sports Sci. 2004;22(8):771–790. PubMed doi:10.1080/026404104 10001712467 10. Sallis JF, Owen N, Fotheringham MJ. Behavioral epidemiology: a systematic framework to classify phases of research on health promotion and disease prevention. Ann Behav Med. 2000;22(4):294–298. PubMed doi:10.1007/BF02895665 11. Nigg CR. There is more to stages of exercise than just exercise. Exerc Sport Sci Rev. 2005;33(1):32–35. PubMed 12. Prochaska JO, DiClemente CC. Stages and processes of self-change in smoking: toward and integrative model of change. J Consult Clin Psychol. 1983;51(3):390–395. PubMed doi:10.1037/0022-006X.51.3.390 13. Wakui S, Shimomitsu T, Odagiri Y, Inoue S, Takamiya T, Ohya Y. Relation of the stages change for exercise behavior, self-efficacy, decisional balance, and diet-related psycho-behavioral factors in young Japanese women. J Sports Med Phys Fitness. 2002;42(2):224–232. PubMed 14. Cheng KY, Cheng PG, Mak KT, Wong SH, Wong YK, Yeung EW. Relationships of perceived benefits and barriers to physical activity, physical activity participation and physical fitness in Hong Kong female adolescents. J Sports Med Phys Fitness. 2003;43(4):523–529. PubMed 15. Nishida Y, Suzuki H, Wang DH, Kira S. Psychological determinants of physical activity in Japanese female employees. J Occup Health. 2003;45(1):15–22. PubMed doi:10.1539/joh.45.15 16. Cardinal BJ, Keis JS, Ferrand C. Comparison of American and French college student’s stage of change for muscular fitness-promoting behaviors. Am J Health Promot. 2006;20(6):388–391. PubMed doi:10.4278/0890-1171-20.6.388 17. Brown SA, Huber D, Bergman A. A perceived benefits and barriers scale for strenuous physical activity in college students. Am J Health Promot. 2006;21(2):137–140. PubMed doi:10.4278/0890-117121.2.137 18. Simonavice EM, Wiggins MS. Exercise barriers, self-efficacy, and stages of change. Percept Mot Skills. 2008;107(3):946–950. PubMed doi:10.2466/pms.107.3.946-950 19. Bopp M, Wilcox S, Oberrecht L, Kammermann S, McElmurray CT. Correlates of strength training in older rural African American and Caucasian women. Women Health. 2004;40(1):1–20. PubMed doi:10.1300/J013v40n01_01 20. Rosenstock IM. Historical origins of the health belief model. Health Educ Monogr. 1974;2:328–335. 21. Ajen I. From intentions to actions: a theory of planned behavior. In: Kuhl J, Beckam J, eds. Action-control: from cognition to behavior. Berlin: Springer-Verlag; 1985:11–39. 22. Booth ML, Bauman A, Owen N, Gore CJ. Physical activity preferences, preferred source of assistance, and perceived barriers to increased activity among physically inactive Australians. Prev Med. 1997;26(1):131–137. PubMed doi:10.1006/pmed.1996.9982 23. Ishii K, Inoue S, Ohya Y, et al. Sociodemographic variation in the perception of barriers to exercise among Japanese adults. J Epidemiol. 2009;19(4):161–168. PubMed doi:10.2188/jea.JE20080094
24. Reichert FF, Barros AJD, Domingues MR, Hallal PC. The role of perceived personal barriers to engagement in leisure-time physical activity. Am J Public Health. 2007;97(3):515–519. PubMed doi:10.2105/ AJPH.2005.070144 25. Dean RN, Farrell JM, Kelley ML, Taylor MJ, Rhodes RE. Testing the efficacy of the theory of planned behavior to explain strength training in older adults. J Aging Phys Act. 2007;15(1):1–12. PubMed 26. Harada K, Oka K, Shibata A, et al. Strength-training behavior and perceived environment among Japanese older adults. J Aging Phys Act. 2011;19(3):262–272. PubMed 27. Harada K, Lee E, Katayama Y, Shibata A, Oka K, Nakamura Y. Koureisha no kinryoku toreningu ni taisuru ninshiki. [Perception of strength training among older people] Supotsu Sangyo Gaku Kenkyu. 2011;20(2):191–197 [J Jpn Soc Sports Ind]. 28. Trost SG, Owen N, Bauman AE, Sallis JF, Brown W. Correlates of adults’ participation in physical activity: review and update. Med Sci Sports Exerc. 2002;34(12):1996–2001. PubMed doi:10.1097/00005768-200212000-00020 29. Rudd J, Glanz K. How individuals use information for health action: Consumer information processing. In: Glanz K, Lewis FM, Rimer BK, eds. Health behavior and health education: theory, research, and practice. San Francisco: Jossey-Bass; 1995:115–132. 30. Graham S, Prapavessis H, Cameron LD. Colon cancer information as a source of exercise motivation. Psychol Health. 2006;21(6):739–755. doi:10.1080/14768320600603554 31. Stretcher V, Rosenstock IM. The Health Belief Model. In: Glanz K, Lewis FM, Rimer BK, eds. Health behavior and health education: theory, research, and practice. San Francisco: Jossey-Bass; 1997:41–59. 32. McAuley E, Jerome GJ, Elavsky S, Marquez DX, Ramsey SN. Predicting long-term maintenance of physical activity in older adults. Prev Med. 2003;37(2):110–118. PubMed doi:10.1016/S00917435(03)00089-6 33. Rhodes RE, Martin AD, Taunton JE. Temporal relationships of selfefficacy and social support as predictors of adherence in a 6-month strength-training program for older women. Percept Mot Skills. 2001;93(3):693–703. PubMed doi:10.2466/pms.2001.93.3.693 34. Myers RS, Roth DL. Perceived benefits of and barriers to exercise and stage of exercise adoption in young adults. Health Psychol. 1997;16(3):277–283. PubMed doi:10.1037/0278-6133.16.3.277 35. Kamada M, Kitayuguchi J, Inoue S, Kamioka H, Mutoh Y, Shiwaku K. Environmental correlates of physical activity in driving and nondriving rural Japanese women. Prev Med. 2009;49(6):490–496. PubMed doi:10.1016/j.ypmed.2009.09.014 36. Inoue S, Ohya Y, Odagiri Y, et al. Association between perceived neighborhood environment and walking among adults in 4 cities in Japan. J Epidemiol. 2010;20(4):277–286. PubMed doi:10.2188/jea. JE20090120 37. National Cancer Institute. Making health communication programs work. Bethesda, MD: National Institutes of Health, U.S. Department of Health and Human Services; 2001.
Official Journal of ISPAH www.JPAH-Journal.com ORIGINAL RESEARCH
Associations Between Perceived Health Benefits and Barriers to Strength Training, and Stages of Change for Strength-Training Behavior Among Older Japanese Adults Kazuhiro Harada, Ai Shibata, Euna Lee, Koichiro Oka, and Yoshio Nakamura Background: Although several studies have examined associations of perceived benefits and barriers with physical activity, no studies have focused on them corresponding to strength-training recommendations for older adults. This study examined the associations among the perceived health benefits of strength training, perceived barriers to strength straining, and stages of change for strength-training behavior in older Japanese adults. Methods: This cross-sectional survey included a random sample of 1144 adults (60–74 years) from the city of Tokorozawa. Stage of change was the independent variable, with perceived health benefits (eg, strength training can reduce body pain) and perceived barriers (eg, facilities are needed for strength training) as dependent variables. Data were analyzed by analysis of covariance and Bonferroni’s multiple comparison. Results: After adjusting for demographic variables, the perceived health-benefit score for precontemplation was significantly lower than for the other four stages. The perceived barrier scores in the precontemplation and contemplation stages were significantly higher than those in the preparation and maintenance stages. Conclusions: These results suggest that information about the health benefits for older adults and about the recommended type of strength training might be useful for the development of strategies to promote strength training among older adults. Keywords: resistance training, motivation, exercise psychology, gerontology, health promotion Current physical activity guidelines, such as the 2008 Physical Activity Guidelines for Americans published by the U.S. Department of Health and Human Services (USDHHS)1 and the 2006 Japanese exercise guidelines issued by the Japan Ministry of Health, Labor, and Welfare (JMHLW)2 recommend strength training for health promotion. Promoting strength training is thus a public health priority. The current recommendations include 2 notable points. First, strength training is recommended for older adults,1,3 as well as for adults in general; since the 1990s, numerous studies have indicated that strength training can reduce the risk of some geriatric problems such as sarcopenia and loss of bone density,4,5 as well as having general health benefits such as reducing the risk of cardiovascular disease and type 2 diabetes.6 In particular, JMHLW emphasizes the benefits of strength training for reducing knee and lower-back pain, as well as risks of bone fractures and falls.3 Second, exercises that do not require any special facilities, equipment, or demonstrations are also recommended for strength training.1,2 For example, in addition to weight-machine training, the USDHHS recommends push-ups, squats, climbing stairs, carrying heavy loads, and heavy gardening for strengthening muscles.1 Nevertheless, older adults are less likely to participate in strength training than younger adults.7,8 According to the impact levels of mass communication campaigns for promoting physical activity,9 disseminating information regarding these current strength-training recommendations (health benefits for older adults, recommended Harada is with the Section for Motor Function Activation, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan. Shibata is with the Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan. Lee, Oka, and Nakamura are with the Faculty of Sport Siences, Waseda University, Tokorozawa, Saitama, Japan.
type of strength training) represents the first important step in promoting strength training in older adults. The identification of modifiable factors associated with physical activity is recognized as an essential phase in the development of effective promotion strategies.10 In addition, the Transtheoretical Model suggests that identifying factors associated with not only actual behavior, but also with intention or motivational readiness, are important for developing more effective promotion of physical activity.11 The central construct of this Transtheoretical Model has been suggested as a favorable framework for understanding both behavior and intention as stages of change.12 Examining the associations between perceived health benefits and barriers, and the stages of change for strength-training behavior would be helpful for investigating if information about current strength-training recommendations is useful for developing strength-training-promotion strategies among older adults. Perceived benefits and barriers are widely used for examining correlates of physical activity13–19 and are key concepts of the health belief model.20 Similar concepts are included in other major psychological theories, such as pros and cons in the Transtheoretical Model,12 and behavioral and control beliefs in the theory of planned behavior.21 If positive associations with perceived health benefits with the stages of change for strengthtraining behavior are observed, it might indicate that information about the health effects in older adults could be useful to promote strength training. With regard to the type of strength training, inconsistent perception of the current recommendations (ie, strength training requires a special facility or equipment) can be regarded as a perceived barrier to strength training, and similar perceptions have been included in the perceived barriers to physical activity.13–19,22–24 If such perceived barriers are negatively associated with stages of change for strength-training behavior, it suggests that information about the recommended type of strength training might be useful 801
802 Harada et al
in developing strategies to promote strength training. Although several studies have analyzed the perceived benefits and barriers to physical activity,13–19 only two have examined their relationships with strength training, either among college students16 or among older women.19 No studies have measured the perceived benefits and barriers corresponding to strength-training recommendations in older adults. The population of frail, older adults has increased dramatically in Japan. The fact that these individuals lose their independence more quickly if they do not maintain their muscle strength has been recognized as an important issue for the health system. The current study, therefore, examined the associations among perceived health benefits of strength training, perceived barriers to strength training, and stage of change for strength-training behavior among older Japanese adults.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Methods Participants and Procedures A cross-sectional questionnaire was distributed through the postal mail to 2092 individuals aged 60–74 years living in Tokorozawa city (population: 341,679; area: 72.0 km2), a typical suburb near Tokyo. A stratified, systematic random method was used to select residential addresses from the city registry. Stratification was performed according to agricultural promotion area (APA). An APA is defined as the area where land use is limited to agriculture by law (the use for other purposes is prohibited in APA), and APAs can thus roughly be regarded as rural areas. The city consists of 11 districts; 3 districts did not include an APA (group A), 5 districts included APAs that were < 50% of the total area (group B), and 3 districts included APAs that were > 50% of the total area (group C). One district was randomly selected from each group. The total population aged 60–74 years in the 3 selected districts was about 12,400. Every sixth person was selected as a participant, according to the order of residential addresses. The survey was conducted in November and December 2009.Twelve of the 2092 individuals did not receive the questionnaire because their addresses were incorrect. A total of 1,288 of the remaining 2080 individuals (61.9%) responded to the questionnaire. Book coupons worth ¥500 were provided as incentives for respondents to the survey. Among these, 33 did not answer the questions for the following reasons: no interest in the survey (n = 14), difficulty in writing or reading (n = 6), lack of time (n = 5), absence of respondent (n = 4), or other (n = 4). A total of 1244 individuals who answered the question about stage of change for strength training behavior (11 individuals had missing data for this question) were included in the analysis (59.8%). A paper explaining the ethical considerations was enclosed with the questionnaire. Individuals were asked to answer and reply to the questionnaire anonymously, only if they understood the ethical considerations and agreed to participate. Return of the questionnaire thus indicated informed consent. This study received prior approval from the Waseda University Ethics Committee (2009-108).
Measurements Stages of Change for Strength Training Behavior. Based on previous studies8,25,26 and the definition provided in the current recommendations,1,2 strength training was defined as all exercise that serves to enhance muscular strength and endurance; regular strength training was regarded as exercise on 2 or more days per week.
The stage-of-change scale for strength-training behaviors8 was employed. This scale consists of 5 choices: precontemplation (not engaged in regular strength training and not intending to engage within the next 6 months), contemplation (intending to engage in strength training within the next 6 months), preparation (engaged in strength training irregularly), action (engaged in regular strength training but for less than 6 months), and maintenance (engaged in regular strength training for the past 6 months or more). Respondents were asked to choose one stage that best described their current condition. Perceived Health Benefits of Strength Training. In the revised
program manual for the improvement of motor function for prevention of long-term care, JMHLW focused on the reduction of body pain (knee and lower back), risk of bone fracture, and risk of falls with regard to the health benefits of strength training for older adults.3 A new scale was developed based on this manual and the existing perceived-benefits scale.13–19 The items were “strength training can enhance muscular strength, even at age 65,” “strength training can enhance muscular strength, even at age 75,” “strength training can enhance muscular strength, even at age 85,” “strength training can reduce body pain,” “strength training can reduce the risk of bone fracture,” “strength training can reduce the risk of fall,” and “strength training can reduce the risk of long-term care need.” These items were evaluated using a 4-point Likert scale: “strongly disagree” (1), “somewhat disagree” (2), “somewhat agree” (3), and “strongly agree” (4). Perceived Barriers to Strength Training. A new scale for perceived barriers to strength training was developed based on a previous qualitative study about perceptions of strength training,27 the existing perceived-barrier scale,13–19,22–24 and the current strengthtraining recommendations.1,2 The items were “strength training is susceptible to injury,” “a facility is necessary for strength training,” “strength training can be done at home,” “instruction is necessary for strength training,” “equipment is necessary for strength training,” “strength training is hard work,” and “strength training is exercise for athletes.” As with the benefits scale, a 4-point Likert scale was used. Demographic Variables. Demographic variables were measured
using the same questionnaire. Variables included age, gender (male; female), self-rated health status (very good; somewhat good; somewhat poor; very poor), number of hospital visits (more than once a week; once or twice a month; once every 2 or 3 months; less than once every 6 months), restriction of physical activity by medical professionals (yes; no), body pain (no; slight; light; moderate; severe; very severe), marital status (currently married; divorced or bereaved; single), smoking habit (current smoker; previous smoker; never smoker), and drinking habit (3 days or more per week; less than 3 days per week; no). For convenient analysis and/or to accommodate small sample sizes in some categories, some demographic variables were collapsed as follows: self-rated health status (good or poor), number of hospital visits (more than once a month or not), body pain (more than moderate pain or not), current marital status (yes or no), current smoking habit (yes or no), current drinking habit (more than 3 days per week or not).
Analyses Regarding missing data for the perceived health benefits and barriers scales, the mean value for the total participants was used if there was one missing item in the scale. If the scale included two or more missing items, the data were excluded from subsequent analyses.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Perceived Benefits and Barriers to Strength Training 803
Confirmatory factor analyses were conducted to identify the construct validities of the perceived health benefits and barriers scales. Regarding floor or ceiling effects, items for which more than 50% of respondents answered “strongly disagree” or “strongly agree” were excluded from the analyses. The models assumed onefactor structure. Goodness of fit index (GFI), comparative fit index (CFI), and root mean square error of approximation (RMSEA) were calculated. If the indexes were not acceptable (GFI or CFI < 0.90, RMSEA < 0.10) or path coefficients were < 0.40, the modified model was examined. Cronbach’s alpha of the scale was calculated. The scores for each item were summarized. Associations between each demographic variable and stage of change for strength-training behavior were analyzed by χ2 tests. Analysis of covariance was used to examine the relationships between stage of change for strength-training behavior and perceived health benefits and barriers. The independent variable was the stage of change and the dependent variables were the scores for the perceived health benefits and the perceived barriers. The covariates were demographic variables that were significantly associated with stage of change according to the χ2 results. Bonferroni’s method was used for post hoc analysis.
Analyses of covariance stratified by gender were also conducted, and associations between each item of the perceived health benefits and barriers scales, and the stages of change were examined. Statistical significance was set at P < .05. All statistical analyses were conducted using SPSS (version 15.0) and AMOS (version 16.0) software packages.
Results Characteristics of the Respondents Table 1 shows the characteristics of the respondents: 51.5% were men (age, 66.5 [SD 4.5] years), and 48.5% were women (age, 66.1 [SD 4.1] years). For all respondents, 84.5% reported good health, 60.0% visited the hospital less than once a month, 93.5% did not restrict their engagement in physical activity because of the advice of medical professionals, 74.6% did not have more than moderate body pain, 85.7% were married, 83.6% did not have a smoking habit, and 67.8% consumed alcohol on 3 or more days per week.
Table 1 Associations Between Demographic Variables and Stage of Change for Strength-Training Behavior Stage of change for strength-training behavior (%) Total Age (years) < 65 65–69 ≥ 70 Gender Male Female Self-rated health status Poor Good Hospital visit < once a month ≥ once a month Restriction of physical activity by medical professionals No Yes Body pain No Yes Marital status Unmarried Married Smoking habit No Yes Drinking habit No Yes
Total (n)
PC (n = 374)
C (n = 279)
PR (n = 281)
A (n = 51)
M (n = 259)
1244
30.1
22.4
22.6
4.1
20.8
480 429 329
29.2 27.7 34.7
24.8 22.6 19.1
20.2 24.5 23.1
6.0 4.0 1.5
19.8 21.2 21.6
638 600
31.2 29.0
21.9 23.2
21.9 23.0
4.5 3.7
20.4 21.2
191 1045
39.3 28.5
24.1 22.2
17.8 23.3
4.7 4.0
14.1 21.9
742 494
29.6 31.0
22.9 21.9
23.0 21.7
4.2 4.0
20.2 21.5
1157 78
29.5 39.7
23.2 14.1
22.6 20.5
4.0 6.4
20.8 19.2
924 314
30.2 29.9
20.1 29.6
22.8 21.3
3.7 5.4
23.2 13.7
177 1059
36.7 29.1
26.6 21.9
17.5 23.2
2.8 4.3
16.4 21.4
1036 203
28.0 40.9
22.1 24.6
22.9 20.7
4.3 3.0
22.7 10.8
839 399
28.6 33.3
22.9 21.6
22.9 21.8
4.2 4.0
21.5 19.3
P value† .021
.822
.009
.938
.165
< .001
.054
< .001
.561
Note. Sample sizes vary because of missing values. Abbreviations: PC, precontemplation; C, contemplation; PR, preparation; A, action; M, maintenance. † χ2 tests.
804 Harada et al
Factor Structure and Internal Consistency for Perceived Health Benefits of Strength Training
= 0.993, CFI = 0.992, and RMSEA = 0.049. Cronbach’s alpha of this model was .78 (Table 3).
The distributions of each item are summarized in Table 2. Confirmatory factor analysis that included all items was conducted initially (initial model). The indexes of this model were poor (GFI = 0.731, CFI = 0.684, RMSEA = 0.270). Correlations were relatively higher among “strength training can enhance muscular strength, even at age 65,” “strength training can enhance muscular strength, even at age 75,” and “strength training can enhance muscular strength, even at age 85” (r = .57–.79). Therefore, “strength training can enhance muscular strength, even at age 65” and “strength training can enhance muscular strength, even at age 85” were excluded because the coefficient for “strength training can enhance muscular strength, even at age 75” was the highest among these 3 items. The indexes of the modified model were GFI
Factor Structure and Internal Consistency for Perceived Barriers to Strength Training Because more than half the participants answered “strongly disagree” to the questions “strength training is susceptible to injury” (50.5%) and “strength training is exercise for athletes” (53.8%), these items were excluded from factor analysis. In the initial model including 5 items, the goodness-of-fit indexes were acceptable: GFI = 0.983, CFI = 0.957, RMSEA = 0.086. However, the coefficient was < 0.40 for “strength training can be done in the home” (–0.392) and a modified model was therefore created that excluded this item. The indexes of the modified model were GFI = 0.999, CFI = 0.999, RMSEA = 0.018 (Table 3). Cronbach’s alpha of this model was .71.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Table 2 Distribution of Items in the Perceived Health Benefits and Barriers Scales n
Strongly disagree (%)
Somewhat disagree (%)
Somewhat agree (%)
Strongly agree (%)
1181
0.8
9.8
46.2
43.2
Perceived health benefits of strength training Strength training can enhance muscular strength, even at age 65 Strength training can enhance muscular strength, even at age 75
1159
3.6
25.6
46.2
24.6
Strength training can enhance muscular strength, even at age 85
1148
13.4
40.3
31.7
14.5
Strength training can reduce body pain
1176
3.0
19.6
53.3
24.1
Strength training can reduce the risk of bone fracture
1169
2.7
16.4
46.4
34.5
Strength training can reduce the risk of fall
1169
2.1
8.0
45.0
44.9
Strength training can reduce the risk of long-term care need
1178
2.9
9.6
45.4
42.1
1155
50.5
38.8
9.9
0.9
A facility is necessary for strength training
1157
44.3
33.6
16.2
6.0
Strength training can be done at home
1201
6.5
10.7
38.5
44.3
Perceived barriers to strength training Strength training is susceptible to injury
Instruction is necessary for strength training
1169
7.7
20.3
52.6
19.4
Equipment is necessary for strength training
1153
17.2
37.4
33.7
11.8
Strength training is hard work
1152
9.3
33.6
43.2
13.9
Strength training is an exercise for athletes
1158
53.8
31.7
8.8
5.7
Table 3 Factor Structure in the Scales of Perceived Health Benefits of Strength Training and Perceived Barriers to Strength Training Scale
Coefficient
Perceived health benefits of strength training (GFI = 0.993, CFI = 0.992, RMSEA = 0.049, α = .78) Strength training can enhance muscular strength, even at age 75 Strength training can reduce body pain Strength training can reduce the risk of bone fracture Strength training can reduce the risk of fall Strength training can reduce the risk of long-term care need
0.41 0.55 0.79 0.82 0.67
Perceived barriers to strength training (GFI = 0.999, CFI = 0.999, RMSEA = 0.018, α = .71) A facility is necessary for strength training Instruction is necessary for strength training Equipment is necessary for strength training
0.69 0.52 0.74
Strength training is hard work
0.52
Perceived Benefits and Barriers to Strength Training 805
Associations Between Demographic Variables and Stage of Change Table 1 shows the associations between demographic variables and stage of change. Of all respondents, 30.1% were in the precontemplation stage, 22.4% were in the contemplation stage, 22.6% were in the preparation stage, 4.1% were in the action stage, and 20.8% were in the maintenance stage. Significant associations with stage of change for strength-training behavior were revealed for age, selfreported health status, body pain, and smoking habits. Those in the action stage were likely to be younger. Poor health status, presence of body pain, and smoking habit were negatively associated with stage of change for strength-training behavior.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Associations Between Stage of Change and Perceived Health Benefits and Barriers After adjusting for demographic variables (age, self-reported health status, body pain, and smoking habits), higher perceived health benefits (F = 23.34, P < .0001, η2 = 0.075) and lower perceived barriers (F = 19.70, P < .0001, η2 = 0.064) were significantly associated with higher stages of change (Figures 1 and 2). In a post hoc analysis, the score for perceived health benefits in the precontemplation stage was significantly lower than that in the other four stages. In addition, the score in the contemplation stage was significantly lower than that in the maintenance stage. There were no significant differences among the scores in later stages (preparation, action, maintenance). Regarding the perceived barriers scale, the scores in the precontemplation and contemplation stages were significantly higher than those in the preparation and maintenance stages. There were
no significant differences in scores among the preparation, action, and maintenance stages. Regarding the results of the additional analyses (Table 4), significant associations between perceived health benefits and barriers, and stages of change were observed in both men (perceived health benefits, F = 11.86, P < .001, η2 = 0.080; perceived barriers, F = 8.97, P < .001, η2 = 0.060) and women (perceived health benefits, F = 11.86, P < .001, η2 = 0.080; perceived barriers, F = 8.97, P < .001, η2 = 0.060). Similarly, all perceived health benefits and barriers scale items were significantly associated with the stages of change (Table 5).
Discussion To the best of our best knowledge, this represents the first study to measure perceived benefits and barriers in relation to current strength-training recommendations for older adults. Although previous studies measured various aspects of perceived benefits and barriers,13–19 they were unsuitable for exploring the usefulness of information about the current recommendations (benefits for older adults, types of strength training) in terms of developing promotion strategies for strength training among older adults. Moreover, few studies have examined the correlates of strength-training behavior among older adults,19,25,26 even though this is essential for developing effective promotion strategies.10 The major finding of this study was that both perceived health benefits and barriers to strength training were associated with the stage-of-change scale for strength training among older Japanese adults. Moreover, additional analyses indicated that all perceived
Figure 1 — Associations between the perceived health benefits of strength training and stage of change for strength-training behavior. The score of perceived health benefits was adjusted for age, self-reported health status, body pain, and smoking habits. * P < .05; ** P < .01; *** P < .001.
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
806 Harada et al
Figure 2 — Associations between the perceived barriers to strength training and stage of change for strengthtraining behavior. The score of perceived barriers was adjusted for age, self-reported health status, body pain, and smoking habits. * P < .05; ** P < .01; *** P < .001.
health benefits and barriers scale items were significantly associated with the stages of change. These results suggest that information about health benefits for older adults and about the recommended type of strength training might be useful for the development of strategies to promote strength training among older adults. Additional analyses also revealed associations between the perceived health benefits and barriers, and the stages of change in both men and women. A previous study19 revealed significant associations between decisional balance (pros-cons: similar concept to perceived benefits and perceived barriers), and strength-training behavior among older adults; however, this previous study only targeted women.19 The current study thus expanded these findings to demonstrate that the associations were irrespective of gender. Post hoc analysis showed that older adults in the precontemplation stage were less likely to perceive the health benefits compared with those in the other four stages. In contrast, among the other four stages, a significant difference in perceived health benefits was revealed only between the contemplation and maintenance stages. These results indicate that perceived health benefits are especially associated with the transition from the precontemplation to the contemplation stage. A previous study in college students revealed significant differences in pros-scale scores for strength training between the precontemplation and higher stages.16 Likewise, a review of physical activity correlates showed that knowledge of health benefits was not directly associated with physical activity.28 Rudd and Glanz29 mentioned that, although knowledge was required for making health-related decisions, it might not be sufficient to change behaviors. Another study identified awareness of the role of exercise in cancer prevention as positively affecting exercise motivation but not maintenance of exercise.30 The perceived health benefits of strength training among older adults might therefore be associated with intention, rather than with strength-training behavior itself.
Although the differences between the action and other stages were not clear, those who did not engage in strength training (precontemplation and contemplation stages) tended to perceive barriers more strongly than those who did engage in strength training (preparation and maintenance stages). Thus, perceived barriers to strength training would inhibit its initiation (ie, the transition from contemplation to preparation or action stages). Some studies found no significant relationship between the perceived barriers (or cons) and the stage-of-change scale for strength training16 and exercise behavior,13 while other studies reported differences in the scores for perceived barriers among college students18 and employees,15 especially between the contemplation and preparation stages for exercise behavior. However, some perceived barriers measured in previous studies,13–19,22–24 such as lack of money or time, would not be easy to modify. However, because current guidelines1,2 recommend types of strength training that do not require special facilities, equipment, or instructions, the perceived barriers measured in the current study could be reduced by providing older adults with information about the recommended types of strength training. There were no significant differences in perceived health benefits and barriers among the preparation, action, and maintenance stages, suggesting that the perceived health benefits and barriers might not be important in terms of developing strategies to reinforce and maintain strength-training behavior among older adults. Previous studies examining the associations between perceived benefits and barriers (or pros and cons) with stage-of-change scales for exercise behavior13,15,18 or strength-training behavior16 also failed to reveal significant differences among the later stages. Theoretically, feelings of self-efficacy to overcome perceived barriers, as well as a perception of the threats and benefits, are needed to initiate and maintain health behaviors requiring long-term changes (eg, physical activity, healthy diet).31 Indeed, physical-activity studies found that self-efficacy was a key factor in the maintenance of behavior
807
0.19 0.21 0.18 0.19
14.05 15.10
10.37 10.51
SE†
10.38 9.68
15.39 15.93
M†
C
0.22 0.21
0.23 0.23
SE†
9.05 9.16
15.50 16.45
M†
P
0.22 0.21
0.22 0.23
SE†
9.65 9.30
15.90 16.25
M†
A
0.47 0.52
0.48 0.57
SE†
9.16 8.49
15.88 17.39
M†
M
0.23 0.22
0.24 0.24
SE†
8.97 13.11
11.86 13.31
F value
< .001 < .001
< .001 < .001
P
0.060 0.098
0.080 0.099
η2
PC,C < P,M PC < C,P,M; C < M
PC < C,P,A,M; C < M PC < P,M; C < M
Post hoc analysis
Analysis of covariance
0.04 0.04
2.60 2.83
0.04
3.07
0.04
0.04
3.12
2.89
0.04
2.95
0.04
0.04
2.76
2.08
0.04
SE
2.73
PC
2.48 2.71
2.90
1.93
3.35
3.34
3.12
3.00
2.88
M
C
0.05 0.05
0.05
0.05
0.04
0.04
0.04
0.04
0.05
SE
2.22 2.54
2.79
1.61
3.33
3.40
3.20
3.06
2.97
M
P
0.05 0.05
0.05
0.05
0.04
0.04
0.04
0.04
0.05
SE
2.40 2.42
3.02
1.70
3.24
3.37
3.17
3.10
3.15
M
A
0.12 0.11
0.11
0.12
0.10
0.09
0.10
0.10
0.11
SE
2.21 2.31
2.71
1.64
3.41
3.54
3.32
3.20
3.13
M
M
Abbreviations: PC, precontemplation; C, contemplation; PR, preparation; A, action; M, maintenance; M, Mean; SE, Standard error. † Adjusted for age, self-reported health status, body pain, and smoking habits.
Items of perceived barriers A facility is necessary for strength training Instruction is necessary for strength training Equipment is necessary for strength training Strength training is hard work
Items of perceived health benefits Strength training can enhance muscular strength, even at age 75 Strength training can reduce body pain Strength training can reduce the risk of bone fracture Strength training can reduce the risk of fall Strength training can reduce the risk of long-term care need
M
0.05 0.05
0.05
0.05
0.05
0.04
0.05
0.04
0.05
SE
11.48 19.90
3.28
16.60
6.51
15.54
10.20
15.77
11.92
F value
< .001 < .001
.011
< .001
< .001
< .001
< .001
< .001
0.036 0.058
0.010
0.051
0.035
0.051
0.033
0.051
0.039
η2
PC,C < P,M PC < P,A,M; C < M
PC < P,A,M; C < P,M
PC < C,P,M; C < M
PC < C,P,M; C < M
PC < C,P,A,M; C < M
PC < P,A,M; C < M
PC < P,A,M; C < M
Post hoc analysis
Analysis of covariance
< .001
P
Table 5 Associations Between Each Item of Perceived Health Benefits and Barriers to Strength Training, and Stages of Change for StrengthTraining Behavior
Abbreviations: PC, precontemplation; C, contemplation; PR, preparation; A, action; M, maintenance, M, Mean; SE, Standard error. † Adjusted for age, self-reported health status, body pain, and smoking habits.
Perceived health benefits Men Women Perceived barriers Men Women
M†
PC
Table 4 Associations Between Perceived Health Benefits and Barriers to Strength Training, and Stages of Change for Strength-Training Behavior Stratified by Gender
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
808 Harada et al
among older adults.32,33 In addition, strength-training studies8,16 indicated that strength training self-efficacy would be an important factor in the transition from preparation/action to maintenance stages for strength training. Thus, approaches such as enhancing self-efficacy might be effective for reinforcing and maintaining strength-training behavior. This study was intended to explore if information about the current recommendations was effective in promoting strength training. The perceived benefits and barriers scales were therefore based on the JMHLW program manual3 and other physical activity recommendations.1,2 Thus, each scale consisted of a one-factor structure, and was not designed to measure other aspects of benefits and barriers (eg, social and psychological). Other scales with several factors, such as the Benefits and Barriers to Exercise Questionnaire,34 would be more appropriate for measuring other aspects of benefits and barriers. The current study had several limitations. First, the analysis was cross-sectional and it was therefore not possible to determine cause and effect. Second, response bias exists in questionnaire surveys; however, our response rate was not low (60%) compared with other questionnaire-based surveys using the postal mailing method, such as 51.6% in Kamada et al35 and 36.5% in Inoue et al.36 In addition, the document provided with the survey stated that the purpose of the survey was to evaluate beliefs regarding strength training among older adults. Those who were not interested in strength training would therefore be less likely to answer the questionnaire. In a previous survey in which this information was not provided, the rate of precontemplation among those > 50 years old was 47%,8 compared with 30% in the current study. In addition, answers to the questionnaire might have been influenced by social desirability and random responses. Moreover, individuals with cognitive impairment would not be able to answer the questionnaire, and it is possible that family members of sampled individuals answered the questionnaire by proxy. Third, despite acceptable internal consistencies and good construct validities, test-retest reliabilities were unclear for the scale of the perceived health benefits and barriers. Further studies are therefore required to confirm the test-retest reliabilities of the scale and to examine causal relationships from a representative sample in which response bias was eliminated. In addition, respondents might have had inaccurate self-perceptions of self-rated health status. Fourth, additional covariates, such as current physical activity level, body mass index, and socioeconomic status should also be incorporated into the survey. The study was also limited by the fact that data were only obtained from one city, which was located in a typical suburban area of Japan. It is therefore unclear if the study findings could be generalized to other populations, such as those in urban or rural areas. It is also possible that the results of this study may not be generalizable to adults of different ethnic backgrounds or from different cultures. The practical implications of the results suggest that disseminating information about the beneficial effects emphasized by JMHLW3 might be useful for increasing the intention of older adults to undergo strength training. In addition, in accordance with current physical activity guidelines,1,2 providing information that push-ups, squats, climbing stairs, carrying heavy loads, and heavy gardening constitute recommended strength-training activities might effectively encourage the initiation of strength training among older adults. Health communication strategies are recognized to useful framework to increase the intended audience’s knowledge and awareness of health issues, problems, and solutions.37 Such communication strategies would be therefore effective to plan and implement the dissemination of information on the health benefits and recommended types of strength training.
Conclusions Perceived health benefits and barriers to strength training are associated with stage-of-change scales for strength training among older Japanese adults. This suggests that information about health benefits for older adults and about the recommended type of strength training might be useful for the development of promotion strategies aimed at strength training among older adults. Acknowledgments We wish to thank Hiroshi Kono (Faculty of Human Life Design, Toyo University), Kyota Takami (Faculty of Sports and Health Sciences, Hosei University), Shinpei Okada (Physical Education and Medicine Research Foundation), Yuko Kai (Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare), Masamitsu Kamada (Japan Society for the Promotion of Science), and Soeko Sakurai (alumna of Graduate School of Sport Sciences, Waseda University) for helpful comments in the design of the current study. This work was supported by a Grant-in-Aid for Research Fellow of the Japan Society for the Promotion of Science (08J0633, 11J07878); Waseda University Grant for Special Research Projects (2010A-093); and Global COE Program ‘Sport Sciences for the Promotion of Active Life’ from the Japan Ministry of Education, Culture, Sports, Science, and Technology.
References 1. United States Department of Health and Human Services. 2008 Physical Activity Guidelines for Americans. U.S. Department of Health and Human Services. http://www.health.gov/paguidelines/pdf/paguide. pdf. Accessed July 26, 2011. 2. Japan Ministry of Health. Labour and Welfare: Kenkou zukuri no tame no undou shishin 2006. [Exercise and physical activity guide for health promotion 2006]. Japan Ministry of Health, Labour and Welfare. http://www.nih.go.jp/eiken/programs/pdf/exercise_guide. pdf. Accessed July 26, 2011. 3. Japan Ministry of Health. Labour and Welfare: Undouki no kinou koujou manyuaru. [Revised manual for the improvement of motor function]. Japan Ministry of Health, Labour and Welfare. http:// www.mhlw.go.jp/topics/2009/05/dl/tp0501-1d.pdf. Accessed July 26, 2011. 4. Chodzko-Zajko WJ, Proctor DN, Fiatarone SMA, et al. American College of Sports Medicine position stand: exercise and physical activity for older adults. Med Sci Sports Exerc. 2009;41(7):1510–1530. PubMed doi:10.1249/MSS.0b013e3181a0c95c 5. Hurley BF, Roth SM. Strength training in the elderly. Sports Med. 2000;30(4):249–268. PubMed doi:10.2165/00007256-20003004000002 6. Williams MA, Haskell WL, Ades PA, et al. Resistance exercise in individuals with and without cardiovascular disease: 2007 update: a scientific statement from the American Heart Association Council on Clinical Cardiology and Council on Nutrition, Physical Activity, and Metabolism. Circulation. 2007;116(5):572–584. PubMed doi:10.1161/ CIRCULATIONAHA.107.185214 7. Chevan J. Demographic determinants of participation in strength training activities among U.S. adults. J Strength Cond Res. 2008;22(2):553–558. PubMed doi:10.1519/JSC.0b013e3181636bee 8. Harada K, Oka K, Shibata A, Ota A, Okada J, Nakamura Y. Factors associated with stages of change for strength training behavior. Int J Sport Health Sci. 2008;6:251–263. doi:10.5432/ijshs.IJSHS20070313 9. Cavill N, Bauman A. Changing the way people think about healthenhancing physical activity: do mass media campaigns have a role?
Downloaded by Purdue Univ on 09/16/16, Volume 11, Article Number 4
Perceived Benefits and Barriers to Strength Training 809 J Sports Sci. 2004;22(8):771–790. PubMed doi:10.1080/026404104 10001712467 10. Sallis JF, Owen N, Fotheringham MJ. Behavioral epidemiology: a systematic framework to classify phases of research on health promotion and disease prevention. Ann Behav Med. 2000;22(4):294–298. PubMed doi:10.1007/BF02895665 11. Nigg CR. There is more to stages of exercise than just exercise. Exerc Sport Sci Rev. 2005;33(1):32–35. PubMed 12. Prochaska JO, DiClemente CC. Stages and processes of self-change in smoking: toward and integrative model of change. J Consult Clin Psychol. 1983;51(3):390–395. PubMed doi:10.1037/0022-006X.51.3.390 13. Wakui S, Shimomitsu T, Odagiri Y, Inoue S, Takamiya T, Ohya Y. Relation of the stages change for exercise behavior, self-efficacy, decisional balance, and diet-related psycho-behavioral factors in young Japanese women. J Sports Med Phys Fitness. 2002;42(2):224–232. PubMed 14. Cheng KY, Cheng PG, Mak KT, Wong SH, Wong YK, Yeung EW. Relationships of perceived benefits and barriers to physical activity, physical activity participation and physical fitness in Hong Kong female adolescents. J Sports Med Phys Fitness. 2003;43(4):523–529. PubMed 15. Nishida Y, Suzuki H, Wang DH, Kira S. Psychological determinants of physical activity in Japanese female employees. J Occup Health. 2003;45(1):15–22. PubMed doi:10.1539/joh.45.15 16. Cardinal BJ, Keis JS, Ferrand C. Comparison of American and French college student’s stage of change for muscular fitness-promoting behaviors. Am J Health Promot. 2006;20(6):388–391. PubMed doi:10.4278/0890-1171-20.6.388 17. Brown SA, Huber D, Bergman A. A perceived benefits and barriers scale for strenuous physical activity in college students. Am J Health Promot. 2006;21(2):137–140. PubMed doi:10.4278/0890-117121.2.137 18. Simonavice EM, Wiggins MS. Exercise barriers, self-efficacy, and stages of change. Percept Mot Skills. 2008;107(3):946–950. PubMed doi:10.2466/pms.107.3.946-950 19. Bopp M, Wilcox S, Oberrecht L, Kammermann S, McElmurray CT. Correlates of strength training in older rural African American and Caucasian women. Women Health. 2004;40(1):1–20. PubMed doi:10.1300/J013v40n01_01 20. Rosenstock IM. Historical origins of the health belief model. Health Educ Monogr. 1974;2:328–335. 21. Ajen I. From intentions to actions: a theory of planned behavior. In: Kuhl J, Beckam J, eds. Action-control: from cognition to behavior. Berlin: Springer-Verlag; 1985:11–39. 22. Booth ML, Bauman A, Owen N, Gore CJ. Physical activity preferences, preferred source of assistance, and perceived barriers to increased activity among physically inactive Australians. Prev Med. 1997;26(1):131–137. PubMed doi:10.1006/pmed.1996.9982 23. Ishii K, Inoue S, Ohya Y, et al. Sociodemographic variation in the perception of barriers to exercise among Japanese adults. J Epidemiol. 2009;19(4):161–168. PubMed doi:10.2188/jea.JE20080094
24. Reichert FF, Barros AJD, Domingues MR, Hallal PC. The role of perceived personal barriers to engagement in leisure-time physical activity. Am J Public Health. 2007;97(3):515–519. PubMed doi:10.2105/ AJPH.2005.070144 25. Dean RN, Farrell JM, Kelley ML, Taylor MJ, Rhodes RE. Testing the efficacy of the theory of planned behavior to explain strength training in older adults. J Aging Phys Act. 2007;15(1):1–12. PubMed 26. Harada K, Oka K, Shibata A, et al. Strength-training behavior and perceived environment among Japanese older adults. J Aging Phys Act. 2011;19(3):262–272. PubMed 27. Harada K, Lee E, Katayama Y, Shibata A, Oka K, Nakamura Y. Koureisha no kinryoku toreningu ni taisuru ninshiki. [Perception of strength training among older people] Supotsu Sangyo Gaku Kenkyu. 2011;20(2):191–197 [J Jpn Soc Sports Ind]. 28. Trost SG, Owen N, Bauman AE, Sallis JF, Brown W. Correlates of adults’ participation in physical activity: review and update. Med Sci Sports Exerc. 2002;34(12):1996–2001. PubMed doi:10.1097/00005768-200212000-00020 29. Rudd J, Glanz K. How individuals use information for health action: Consumer information processing. In: Glanz K, Lewis FM, Rimer BK, eds. Health behavior and health education: theory, research, and practice. San Francisco: Jossey-Bass; 1995:115–132. 30. Graham S, Prapavessis H, Cameron LD. Colon cancer information as a source of exercise motivation. Psychol Health. 2006;21(6):739–755. doi:10.1080/14768320600603554 31. Stretcher V, Rosenstock IM. The Health Belief Model. In: Glanz K, Lewis FM, Rimer BK, eds. Health behavior and health education: theory, research, and practice. San Francisco: Jossey-Bass; 1997:41–59. 32. McAuley E, Jerome GJ, Elavsky S, Marquez DX, Ramsey SN. Predicting long-term maintenance of physical activity in older adults. Prev Med. 2003;37(2):110–118. PubMed doi:10.1016/S00917435(03)00089-6 33. Rhodes RE, Martin AD, Taunton JE. Temporal relationships of selfefficacy and social support as predictors of adherence in a 6-month strength-training program for older women. Percept Mot Skills. 2001;93(3):693–703. PubMed doi:10.2466/pms.2001.93.3.693 34. Myers RS, Roth DL. Perceived benefits of and barriers to exercise and stage of exercise adoption in young adults. Health Psychol. 1997;16(3):277–283. PubMed doi:10.1037/0278-6133.16.3.277 35. Kamada M, Kitayuguchi J, Inoue S, Kamioka H, Mutoh Y, Shiwaku K. Environmental correlates of physical activity in driving and nondriving rural Japanese women. Prev Med. 2009;49(6):490–496. PubMed doi:10.1016/j.ypmed.2009.09.014 36. Inoue S, Ohya Y, Odagiri Y, et al. Association between perceived neighborhood environment and walking among adults in 4 cities in Japan. J Epidemiol. 2010;20(4):277–286. PubMed doi:10.2188/jea. JE20090120 37. National Cancer Institute. Making health communication programs work. Bethesda, MD: National Institutes of Health, U.S. Department of Health and Human Services; 2001.
