Participants and Procedure
The study was a cross-sectional study using a census sample of 120 elder men aged 60 to 85 years in a population of elderly men, who constituted whole resident of Kahrizak nursing home in Tehran, Iran. The Institutional Review Board of the approved and supported the study. After institutional ethical approval, the investigators were introduced to Kahrizak nursing home by research administration of . The objectives and methodology of the study was explained to the management of Kahrizak Nursing Home, and its approval was obtained.
The sample size, calculated using an α of 0.05 and a power of 0.95, was found to be 120 individuals. Therefore, 120 old men possessing the inclusion criteria were selected.
The inclusion criteria for the study were an age of 60 years or older, independent living (no assistance from paid or unpaid persons for personal care), no suffering from several diseases including osteoarthritis, heart diseases, osteoporosis, pulmonary diseases, and ability for independent mobility (moving without canes, etc.), and ability of verbal communication.
Each participant was given a packet of questionnaires on physical activity that contained questions in regards to the assessment of physical activity intention, behavior, attitude, subjective norm, PBC, and self-efficacy. The study was developed according to procedures defined by Ajzen and Fishbein.24
Participants were individually interviewed for 45 minutes using questions in regards to their demography, physical activity beliefs, and physical activity behavior, respectively. The interviewer explained questionnaires used for data collection to the participants to prevent illiteracy or vision difficulties from affecting the study participation or findings.
In order to assure the validity of the Persian version of the questionnaire, it was translated into Persian and then back into English. The translation and back translation were performed by two different linguistic students. The translations were then compared and the questionnaire was corrected accordingly.
The questionnaire was then given to 10 professionals in Health Education, sociology and Gerontology at to examine the item clarity, face validity, and content validity. The questionnaire was then modified based on their suggestions and comments.
Reliability of the questionnaire was evaluated using a sample of 20 subjects over 10 days using test-retest for physical activity behavior, and Cronbach’s alpha for other items.
Participants were instructed to answer all questions based on the definition of regular physical activity. Regular physical activity was defined as a moderately intense physical activity (such as brisk walking) that is performed ideally every day for a minimum of 30 minutes. The duration of regular physical activity may be fulfilled either in a single session or accumulated in multiple bouts of at least 8–10 minutes throughout the day. Questions of TPB were based on previously used measures of TPB constructs, and were all measured on 7-point scales.13
Physical Activity Intention
Physical activity intention was measured with a single item modeled after Ajzen’s work in 1999. Subjects were asked about the extent of their agreement with the statement that they intend to perform regular physical activity.
Physical Activity Behavior
Physical activity was measured using the Physical Activity Scale for the Elderly (PASE).25
The PASE is a brief instrument designed specifically to assess the frequency and duration of recreational, leisure, and occupational physical activity in older adults over a 7-day period. Frequency was categorized by as never, seldom (1-2 days/week), sometimes (3-4 days/week), and often (5-7 days/week). Duration was categorized as less than 1 hour, between 1-2 hours, 2-4 hours, and more than 4 hours. The total PASE score was computed by multiplying the duration of time spent in each activity or participation (yes/no) by the empirically-derived item weights, and summing up all activities. A higher PASE score represents a greater physical activity behavior. Reliability, evaluated in 20 subjects over 10 days, was (correlation coefficient=0.76).
Physical Activity Attitude
The participants' attitude was assessed using the statement “For me, participating in regular physical activity would be”. The answers assessed components of both instrumental attitude (useful/useless, healthy/unhealthy, bad/good) and affective attitude (enjoyable/unenjoyable, boring/interesting, pleasant/unpleasant, stressful/relaxing). Answers were adjectives that are commonly employed in the physical activity domain.24
Cronbach’s alpha for affective attitude (α=0.74) and instrumental attitude (α=0.81) were good.
Subjective norm was operationalized by three statements: “people close to me think that I should participate in regular physical activity”, “people who are important to me think that I should participate in regular physical activity”, and “my doctor thinks that I should participate in physical activity.” These items were scored using seven-point scales from 1 (strongly disagree) to 7 (strongly agree). Cronbach’s alpha for this part was 0.71.
Perceived Behavioral Control
Perceived behavioral control (PBC) was measured by four questions. The first question was how much control the subjects had over participating in regular physical activity scored from 1 (very little control) to 7 (complete control). The second question was whether or not the subjects could easily participate in regular physical activity if they wanted. The answer to this question was scored from 1 (strongly disagree) to 7 (strongly agree). The next question was how confident were the subjects that they were capable of participating in regular physical activity. The level of confidence was ranked from 1 (not at all confident) to 7 (extremely confident). The fourth question was about extent of control that the subjects had over the amount of time they had for physical activity. The extent of the control was ranked from 1 (very little control) to 7 (complete control). Cronbach’s alpha for PBC was 0.73.
We adapted the physical activity self-efficacy scale.26
This 5-item instrument was designed to assess confidence in the ability to overcome the barriers for increasing physical activity in various situations. A 4-point likert scale from 1 (very uncertain) to 4 (very certain) was used for scoring. Cronbach’s alpha for this part was 0.85.
Data were analyzed using the Statistical Package for Social Sciences (SPSS, v. 13). Descriptive statistics were used to determine means and standard deviations of all constructs.
Kolmogorov-smirnov test was used to examine the normality of distribution of quantitative data. Quantitative data were analyzed using Pearson correlation coefficients or multiple Regression.