Evaluations of validity and reliability of a transtheoretical model for sedentary behavior among college students

Objective: To evaluate the measurement properties of the Transtheoretical Model (TTM) questionnaire for sedentary behaviors among college students and to examine the validity and reliability of the developed TTM questionnaire. Methods: Overall, 225 college students were recruited. For the 2-week test-retest reliability, a random sub-sample (N = 108) of the participants was used. Results: Statistically significant differences were found across the stages on the tests of concurrent (X2 = 25.0, p < .001) and construct (p < .01) validity. In addition, the internal consistency reliability (Cronbach alphas from .73 to .88) and test-retest reliability (intra-class correlation coefficients ranging from .80 to .94) were high for the questionnaires. Conclusions: These results demonstrate high validity and reliability of the TTM questionnaire when applied to sedentary behavior.Peer reviewedCommunity Health Sciences, Counseling and Counseling Psycholog

Application of the transtheoretical model to sedentary behaviors and its association with physical activity status

Background: The Transtheoretical Model (TTM) is a successful framework for guiding behavior change programs for several health behaviors, yet its application to reduce of sedentary behavior has been neglected. In addition, no data exist regarding the association between determinants of sedentary behaviors based on the TTM and physical activity behavior. The purpose of this study was to investigate college students' stages of motivational readiness to avoid sedentary behaviors and relevant psychological determinants using newly developed TTM questionnaires and to identify the association between current physical activity and sedentary behaviors based on TTM constructs.Methods: Data were obtained from 225 college students enrolled in health education and physical education courses. Participants completed a package of questionnaires including validated TTM, physical activity and sitting time questionnaires. Participants also wore an accelerometer for seven consecutive days. MANOVAs were conducted to determine mean differences in psychological constructs across the TTM stages, and Chi-square tests and Spearman correlation were used to evaluate the associations between current physical activity and sedentary behavior.Results: A majority of the participants were in the sedentary stages, and men and women differed in proportion of individuals in the stages (78.0% vs. 68.1%, respectively). The gender difference was also found in use of the processes of change. In general, the mean scores of the TTM constructs increased as the stages progressed. No significant associations were found between the TTM constructs for sedentary behavior and current physical activity levels (p>0.05).Conclusions: A high proportion of college students were in sedentary stages regardless of physical activity levels, but different distributions in men and women. Participants in earlier stages were less likely to utilize the TTM constructs to reduce sedentary behaviors than those in later stages. A lack of association between physical activity and the psychological determinants of sedentary behavior was found.Peer reviewedCommunity Health Sciences, Counseling and Counseling Psycholog

Maximal exercise hemodynamics and risk of mortality in apparently healthy men and women

The use of exercise electrocardiography (ECG) to detect latent coronary heart disease (CHD) is discouraged in apparently healthy populations because of low sensitivity. These recommendations however, are based on the efficacy of evaluation of ischemia (ST segment changes) with little regard for other measures of cardiac function that are available during exertion. The purpose of this investigation was to determine the association of maximal exercise hemodynamic responses with risk of mortality due to all-causes, cardiovascular disease (CVD), and coronary heart disease (CHD) in apparently healthy individuals. Study participants were 20,387 men (mean age = 42.2 years) and 6,234 women (mean age = 41.9 years) patients of a preventive medicine center in Dallas, TX examined between 1971 and 1989. During an average of 8.1 years of follow-up, there were 348 deaths in men and 66 deaths in women. In men, age-adjusted all-cause death rates (per 10,000 person years) across quartiles of maximal systolic blood pressure (SBP) (low to high) were: 18.2, 16.2, 23.8, and 24.6 (p for trend $\u3c$0.001). Corresponding rates for maximal heart rate were: 28.9, 15.9, 18.4, and 15.1 (p trend $\u3c$0.001). After adjustment for confounding variables including age, resting systolic pressure, serum cholesterol and glucose, body mass index, smoking status, physical fitness and family history of CVD, risks (and 95% confidence interval (CI)) of all-cause mortality for quartiles of maximal SBP, relative to the lowest quartile, were: 0.96 (0.70-1.33), 1.36 (1.01-1.85), and 1.37 (0.98-1.92) for quartiles 2-4 respectively. Similar risks for maximal heart rate were: 0.61 (0.44-0.85), 0.69 (0.51-0.93), and 0.60 (0.41-0.87). No associations were noted between maximal exercise rate-pressure product mortality. Similar results were seen for risk of CVD and CHD death. In women, similar trends in age-adjusted all-cause and CVD death rates across maximal SBP and heart rate categories were observed. Sensitivity of the exercise test in predicting mortality was enhanced when ECG results were evaluated together with maximal exercise SBP or heart rate with a concomitant decrease in specificity. Positive predictive values were not improved. The efficacy of the exercise test in predicting mortality in apparently healthy men and women was not enhanced by using maximal exercise hemodynamic responses. These results suggest that an exaggerated systolic blood pressure or an attenuated heart rate response to maximal exercise are risk factors for mortality in apparently healthy individuals

Relationships between physical activity and sedentary behaviors.

<p>Relationships between physical activity and sedentary behaviors.</p

Stage distributions (%) and median minutes of sedentary time (m/w) for each stage by gender.

<p>PC = precontemplation; C = contemplation; P = preparation; A = action; M = maintenance.</p

Means of the TTM constructs with standard deviations across stages of motivational readiness for sedentary behaviors.

<p>Means of the TTM constructs with standard deviations across stages of motivational readiness for sedentary behaviors.</p

Means and standard deviations for the TTM constructs for sedentary behaviors between the two groups of meeting and non-meeting physical activity guidelines.

<p>Means and standard deviations for the TTM constructs for sedentary behaviors between the two groups of meeting and non-meeting physical activity guidelines.</p

Demographic characteristics.

<p>Demographic characteristics.</p

Stage distributions and weekly median and mean sedentary minutes unadjusted and adjusted for wear time by gender.

<p>Stage distributions and weekly median and mean sedentary minutes unadjusted and adjusted for wear time by gender.</p