Mediators of physical activity behavior change: findings from a 12-month randomized controlled trial

OBJECTIVE

To examine putative mediators of a 12-month motivationally tailored physical activity (PA) promotion intervention.

DESIGN

We randomly assigned 239 healthy, underactive adults (moderate-vigorous physical activity <90 min/week; mean age = 47.5 years; 82% women) to receive (a) print-based feedback, (b) phone-based feedback, or (c) contact control.

PRIMARY OUTCOME

PA at baseline, 6, and 12 months, as measured by the 7-day physical activity recall interview. MEDIATORS: Four TransTheoretical Model constructs explicitly targeted by the intervention (i.e., self-efficacy, decisional balance, cognitive and behavioral processes of change), as well as four additional constructs linked to PA behavior change (i.e., social support, outcome expectancy, PA enjoyment, exercise-induced feelings).

RESULTS

Multivariate mediation analyses were used to analyze longitudinal PA outcomes. Changes in behavioral processes and one aspect of exercise-induced feelings (revitalization) satisfied both action theory (i.e., treatment effects on mediators) and conceptual theory (i.e., mediator effects on PA) tests at 6 and 12 months and emerged as statistically significant mediators of treatment effects on PA across delivery channels (ps <.014). Cognitive processes, self-efficacy, decisional balance, and social support for PA participation satisfied Action Theory tests at both 6 and 12 months, but failed conceptual theory tests. Delayed intervention effects were observed on other aspects of exercise-induced feelings, PA enjoyment, and outcome expectancies, but these variables failed mediation testing at 12 months.

CONCLUSION

Findings are consistent with previous research illustrating the importance of behavioral processes of change, but also indicate that affective response to PA may warrant more attention as a potential target of behavior change programs.

Internet-Based Physical Activity Intervention Targeting Young Adult Cancer Survivors

Purpose: Young adults who have been treated for cancer face several health and psychosocial risks. To minimize these risks, is it imperative that they address any modifiable risk factors, such as sedentary lifestyle. Unfortunately, more than half of young adult cancer survivors remain sedentary. To facilitate the adoption of physical activity (PA) in this population-potentially reducing health and psychosocial risks-we developed and pilot tested an internet-based PA intervention for young survivors. Patients and methods: Eighteen young adults, aged 18 to 39, who had been diagnosed with cancer in the past 10 years were recruited. Participants were randomized to receive access to the PA website for 12 weeks or information about other cancer-related websites. Intervention feasibility and acceptability was assessed only among those in the PA website group; PA and psychosocial outcomes (mood, fatigue) were assessed in both groups. Results: Findings revealed that 86% of participants in the PA website group would recommend the intervention to others and most (71%) were "satisfied" or "very satisfied" with it. Further, 100% rated getting onto the website as "very easy" and 86% rated the information on the site as "very easy" to understand. The logging feature, followed by the goal-setting feature, were most often accessed by participants. Participants also rated the graphing and stage-matched manual features as helpful. Estimates of effect sizes for between-group differences at 12 weeks were medium for PA outcomes and large for psychosocial outcomes. Conclusions: This internet-based PA intervention targeting young adult cancer survivors is feasible and acceptable and may benefit this population.

Does tailoring on additional theoretical constructs enhance the efficacy of a print-based physical activity promotion intervention?

OBJECTIVE

To enhance a previously efficacious individually tailored physical activity (PA) promotion intervention by adding theoretical constructs to the tailored feedback.

DESIGN

We randomly assigned 248 healthy, underactive (moderate to vigorous physical activity [MVPA] min/week < 90) adults (mean age = 48.8 years, SD = 10.0) to receive either (a) a theoretically tailored (based on 5 constructs from the transtheoretical model and social-cognitive theory [SCT]) print-based PA promotion intervention (print) or (b) the same theoretically tailored print-based PA promotion intervention plus enhanced tailoring addressing 5 additional SCT constructs (enhanced print).

MAIN OUTCOME MEASURE

The 7-day physical activity recall administered at baseline, Month 6, and Month 12, with outcomes operationalized as percentage achieving 150 min/week of MVPA.

RESULTS

When controlling for covariates, there was a nonsignificant trend in favor of the enhanced print condition reflecting 46% and 50% greater odds of achieving 150 min/week of MVPA at Month 6 and Month 12, respectively.

CONCLUSION

Enhanced tailoring based on additional theoretical constructs may result in marginal improvements in physical activity outcomes.

Acute effects of moderate intensity aerobic exercise on affective withdrawal symptoms and cravings among women smokers

A growing number of laboratory studies have shown that acute bouts of aerobic exercise favorably impact affect and cravings among smokers. However, randomized trials have generally shown exercise to have no favorable effect on smoking cessation or withdrawal symptoms during quit attempts. The purpose of the present study was to explore this apparent contradiction by assessing acute changes in affect and cravings immediately prior to and following each exercise and contact control session during an eight-week smoking cessation trial. Sixty previously low-active, healthy, female smokers were randomized to an eight-week program consisting of brief baseline smoking cessation counseling and the nicotine patch plus either three sessions/week of moderate intensity aerobic exercise or contact control. Findings revealed a favorable impact of exercise on acute changes in positive activated affect (i.e., energy), negative deactivated affect (i.e., tiredness), and cigarette cravings relative to contact control. However, effects dissipated from session to session. Results suggest that aerobic exercise has potential as a smoking cessation treatment, but that it must be engaged in frequently and consistently over time in order to derive benefits. Thus, it is not surprising that previous randomized controlled trials-in which adherence to exercise programs has generally been poor-have been unsuccessful in showing effects of aerobic exercise on smoking cessation outcomes.

Feasibility of using computer-tailored and internet-based interventions to promote physical activity in underserved populations

OBJECTIVE

Computer-tailored and Internet-based interventions to promote physical activity behavior have shown some promise, but only few have been tested among African Americans. We examined the feasibility and efficacy of three 1-year, multiple contact physical activity interventions (Tailored Internet, Tailored Print, Standard Internet) in a subsample of African American participants (n = 38) enrolled in a randomized controlled trial.

MATERIALS AND METHODS

Participants randomly assigned to Tailored Internet and Print programs received individually tailored computer expert system feedback delivered via Internet or print. Participants in the Standard Internet program received access to six currently available physical activity Web sites. Self-reported physical activity was assessed at baseline and 6 and 12 months with the 7-Day Physical Activity Recall.

RESULTS

Across all participants, physical activity changed from 17.24 min/week (standard deviation [SD] = 20.72) at baseline to 139.44 min/week (SD = 99.20) at 6 months, to 104.26 min/week (SD = 129.14) at 12 months. According to available consumer satisfaction data (n = 30), 70% reported reading most or all of the physical activity information received by Internet or mail. Most participants described the Internet- and print-based physical activity programs as "somewhat" or "very" helpful (80%) and enjoyable (87%).

CONCLUSIONS

These findings suggest that computer-tailored and Internet-based interventions are able to produce long-term increases in physical activity and associated process variables among African American participants. Future studies with larger numbers of African American participants are needed to determine which of the programs (Tailored Print, Tailored Internet, Standard Internet) are more effective and what program modifications might be helpful in assisting this population in becoming more active.

Moderate intensity exercise as an adjunct to standard smoking cessation treatment for women: a pilot study

Previous randomized controlled trials have not supported moderate intensity exercise as an efficacious adjunct to smoking cessation treatments for women; however, compliance with exercise programs in these studies has been poor. The purpose of this pilot study was to estimate the effects of moderate intensity exercise on smoking cessation outcomes under optimal conditions for exercise program compliance. Sixty previously sedentary, healthy, female smokers were randomized to an 8-week program consisting of brief baseline smoking cessation counseling and the nicotine patch plus either 150 min/week of moderate intensity exercise or contact control. Participants attended a median of 86.4% and 95.5% of prescribed exercise/control sessions, respectively. There was a moderate, though statistically nonsignificant, effect of exercise at post-treatment for objectively verified 7-day point prevalence abstinence (48.3% vs. 23.3%; OR = 3.07, 95% CI: 0.89-11.07) and prolonged abstinence (34.5% vs. 20.0%; OR = 2.11, 95% CI: 0.56-8.32). Effects were attenuated when controlling for potential confounders, and after a 1-month, no-treatment period. The findings provide a preliminary indication that, given adequate compliance, moderate intensity exercise may enhance short-term smoking cessation outcomes for women; however, a larger trial is warranted.

Risk perception and smoking behavior in medically ill smokers: a prospective study

AIMS

To examine the influence of risk perception on intentions to quit smoking and post-treatment abstinence.

DESIGN

Prospective and longitudinal.

SETTING

United States.

PARTICIPANTS

A total of 237 adult smokers (mean age 56 years) receiving medical care from home health-care nurses. Participants did not have to want to quit smoking to participate, but received cessation counseling within the context of their medical care.

MEASUREMENTS

Three measures of risk perception were given pre- and post-treatment: perceived vulnerability, optimistic bias and precaution effectiveness. Smoking status was verified biochemically at end of treatment and at 2, 6 and 12 months later.

FINDINGS

Principal components analysis supported the theoretical discriminability of the risk perception measures, and intercorrelations provided evidence for concurrent and predictive validity. Elevated risk perception was associated with a variety of socio-demographic and psychosocial characteristics. Optimistic bias was associated significantly with older age and ethnic minority status. Smokers in pre-contemplation had lower perceived vulnerability and precaution effectiveness and greater optimistic bias than those in contemplation and preparation. Smokers in preparation had higher perceived vulnerability and lower optimistic bias than those in earlier stages. Change in perceived vulnerability predicted smoking cessation at follow-up. Optimistic bias predicted a lower likelihood of cessation and precaution effectiveness predicted a greater likelihood of smoking cessation, but only among those with a smoking-related illness.

CONCLUSIONS

In patients receiving medical care from home health-care nurses, change in perceived vulnerability to smoking-related disease is predictive of smoking cessation. In those with smoking-related illnesses, optimistic bias predicts continued smoking while precaution effectiveness predicts cessation.

Physical activity interventions and changes in perceived home and facility environments

OBJECTIVE

To examine changes in environmental perceptions over time and associations between changes in perceptions and physical activity among participants in two physical activity interventions.

METHODS

Two independent trials were examined. Project STRIDE (STRIDE) (N=239) was conducted from 2000 to 2004 in Rhode Island. Step into Motion (SIM) (N=249) was conducted from 2003 to 2006 in Rhode Island and Pennsylvania. Both trials tested various delivery channels for providing individually tailored motivational materials to increase physical activity among sedentary adults. Neither intervention aimed to change perceptions of the environment. At baseline, 6, and 12 months, surveys assessed physical activity and perceived facility and home equipment availability.

RESULTS

In both trials, perceived facility availability increased from baseline to 6 months. Significant increases continued from 6 to 12 months in SIM only. Increases were not significantly different by treatment group. Perceived home equipment availability also increased from baseline to 6 months in both trials and from 6 to 12 months in SIM only. In STRIDE, greater increases were observed for intervention compared to control participants. Increased facility and home equipment availability were associated with increased minutes of physical activity in both trials.

CONCLUSIONS

Perceived facility and home equipment availability improved during participation in two individual-level physical activity interventions.

A culturally adapted physical activity intervention for Latinas: a randomized controlled trial

BACKGROUND

In the U.S., Latinos report particularly high levels of inactivity and related chronic illnesses and are in need of intervention. Thus, the purpose of the current study was to culturally and linguistically adapt an empirically supported, individually tailored physical activity print intervention for Latinos and then conduct an RCT of the modified program.

DESIGN

An RCT was conducted.

SETTING/PARTICIPANTS

The sample included 93 overweight/obese (80%) Latinas with low income and acculturation.

INTERVENTION

Data were collected in 2007-2008 and analyzed by intent-to-treat in 2009. Participants were randomly assigned to either (1) a culturally and linguistically adapted physical activity intervention (Seamos Activas) or (2) a wellness contact control condition.

MAIN OUTCOME MEASURES

Self-report physical activity, as measured pre- and post-intervention (6 months, 87% retention) by the 7-Day Physical Activity Recall.

RESULTS

Moderate-intensity (or greater) physical activity increased from an average of 16.56 minutes/week (SD=25.76) at baseline to 147.27 (SD=241.55) at 6 months in the intervention arm (n=45), and from 11.88 minutes/week (SD=21.99) to 96.79 (SD=118.49) in the wellness contact control arm (n=48). No between-group differences were seen in overall physical activity. Intervention participants reported significantly greater increases in cognitive (F[1, 91]=9.53, p=0.003) and behavioral processes of change (F[1, 91]=8.37, p=0.005) and available physical activity supplies and equipment at home (F[1, 91]=4.17, p=0.04) than control participants.

CONCLUSIONS

Results supported the hypothesized feasibility, acceptability, and preliminary efficacy of individually tailored physical activity print interventions among Latinas. Although more research is needed to corroborate these findings, such high-reach, low-cost approaches have great potential to positively affect public health.

TRIAL REGISTRATION

NCT00724165.

Exercise and relaxation intervention for breast cancer survivors: feasibility, acceptability and effects

OBJECTIVE

Although evidence mounts regarding the beneficial effects of physical activity (PA) interventions for breast cancer survivors, not all interventions have produced significant improvement in mood. Relaxation training may be a promising strategy for enhancing mood effects from these interventions. The goals of Be Calm and Move On were to assess the feasibility, acceptability and preliminary effects of a 12-week combined PA and relaxation intervention for breast cancer survivors.

METHODS

Twenty-three early-stage breast cancer survivors were enrolled and 19 were retained for the intervention and 12- and 24-week follow-ups. Participants received a theoretically grounded intervention delivered via telephone.

RESULTS

Participant evaluations of the intervention indicated that it was feasible and acceptable (e.g. 100% would recommend it to others); objective data further supported its feasibility (e.g. 83% completed the trial, 91% of intervention calls were received). In addition, when comparing 12- and 24-week follow-up data to baseline data, participants demonstrated significantly increased PA, improved mood and sleep quality, and reduced fatigue (p's<0.05).

CONCLUSION

Thus, this pilot study suggests that the intervention is feasible and acceptable and produces promising effects on mood, sleep, and fatigue.

Home-based exercise among cancer survivors: adherence and its predictors

OBJECTIVE

Evidence of the benefits of exercise for those treated for cancer has led to exercise interventions for this population. Some have questioned whether cancer patients offered a home-based intervention adhere to the exercise prescribed.

METHOD

We examined exercise adherence in a randomized controlled trial of a 12-week, home-based exercise trial for breast cancer patients. Three adherence outcomes were examined: minutes of exercise participation/week, number of steps taken during planned exercise/week, and whether the participant met her weekly exercise goal. Predictors of adherence (e.g. demographic and medical variables, Transtheoretical Model variables, history of exercise) were examined.

RESULTS

Findings indicate that participants significantly increased their minutes of exercise and steps taken during planned exercise from Week 1 to 12. The percentage of participants achieving exercise goals was highest in the first few weeks. Exercise self-efficacy significantly predicted each adherence outcome. Baseline PA predicted mean exercise session steps over the 12 weeks.

CONCLUSION

Adherence to a home-based exercise intervention for breast cancer patients changes over time and may be related to baseline levels of exercise self-efficacy.

Recruitment of a racially and ethnically diverse sample into a physical activity efficacy trial

BACKGROUND

Healthy People 2010 underscores the relevance of eliminating health disparities. Thus, it is paramount to create interventions that promote health for all individuals.

PURPOSE

This study examined differences in rates of and reasons for ineligibility among non-Hispanic blacks and whites in a randomized controlled physical activity intervention study.

METHODS

Participants (1245 adults) responded to community advertising for the research study. Eligibility at the four pre-randomization assessment sessions was determined by self-reported medical information, resting EKG, 7-Day Physical Activity Recall, fitness test and Stage of Change. We used t-tests to examine the rates of eligibility among participant subgroups.

RESULTS

Blacks had higher rates of overall ineligibility (86.9%) than whites (75.1%; p < 0.01) and were more likely to be ineligible due to lack of interest or no-show at a pre-randomization appointment (35.4% vs. 24.3%; p < 0.01). Blacks were more likely to be ineligible for medical reasons after the telephone screen (16.3% vs. 7.8%; p = 0.01).

LIMITATIONS

This study did not use a random sampling of potential participants from each of the racial/ethnic groups and thus, there is the potential for selection bias.

CONCLUSIONS

Blacks were more likely to choose not to enroll in the study due to a lack of interest, but had similar rates of overall medical ineligibility to whites. This highlights the importance of strategies that enhance interest among blacks, who initially respond to recruitment advertising.

User attitudes towards physical activity websites in a randomized controlled trial

OBJECTIVE

To better understand the mixed findings regarding the efficacy of Internet-based physical activity interventions, we examined the use and usefulness of particular website components that may lead to improvements in intervention efficacy.

METHOD

Participants were sedentary individuals from a 12-month randomized controlled physical activity trial conducted in Providence, Rhode Island and Pittsburgh, Pennsylvania from 2003-2006. The present study included participants from the Tailored Internet arm (n=81; instantaneous web-based tailored feedback to participants) or the Standard Internet arm (n=82; websites currently available to the public). We obtained objective data via the intervention websites and subjective usefulness data via questionnaires.

RESULTS

The Tailored Internet arm logged onto their website significantly more times than the Standard Internet arm (median 50 vs. 38; p<.05). Among participants in the Tailored Internet arm, the self-monitoring feature (i.e., logging) followed by goal setting were rated as the most useful website components.

CONCLUSION

Logins in the current study were substantially higher compared to previous studies. Participants endorsed goal setting and self-monitoring as being most useful, which are critical components for health behavior change. Future studies should continue to examine these features and improve the perceived usefulness of other theory-based strategies.

A comparison of Internet and print-based physical activity interventions

BACKGROUND

Physical activity interventions tailored to individual characteristics and delivered via print produce greater increases in activity compared with nontailored interventions and controls. Using the Internet to deliver a tailored physical activity intervention offers an alternative to print that might be available to larger populations at a lower cost.

METHODS

Participants (N=249 adults; mean [SD] age, 44.5 [9.3] years; and mean [SD] body mass index [calculated as weight in kilograms divided by height in meters squared], 29.4 [6.1]) were randomized to 1 of 3 physical activity interventions: (1) motivationally tailored Internet (tailored Internet, n=81), (2) motivationally tailored print (tailored print, n=86); and (3) 6 researcher-selected Web sites available to the public (standard Internet, n=82). Participants in the tailored Internet and tailored print arms received the same tailored intervention content. Participants were assessed at baseline and at 6 and 12 months.

RESULTS

At 6 months, participants in the tailored print arm reported a median of 112.5 minutes of physical activity per week, those in the tailored Internet arm reported 120.0 minutes, and those in the standard Internet arm reported 90.0 minutes (P=.15). At 12 months, the physical activity minutes per week were 90.0, 90.0, and 80.0 for those in the tailored print, tailored Internet, and standard Internet arms, respectively (P=.74). Results indicated no significant differences between the 3 arms.

CONCLUSIONS

The use of tailored Internet, tailored print, and standard Internet as part of a behavior change program increased physical activity behavior similarly. Because the use of the Internet was not different from the print-based intervention, this may be an opportunity to reach more sedentary adults in a more cost-effective way.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00200317.

Evidence for static magnetism in the vortex cores of ortho-II YBa2Cu3O6.50

Evidence for static alternating magnetic fields in the vortex cores of underdoped YBa2Cu3O6+x is reported. Muon spin rotation measurements of the internal magnetic field distribution of the vortex state of YBa2Cu3O6.50 in applied fields of H = 1 T and H = 4 T reveal a feature in the high-field tail of the field distribution which is not present in optimally doped YBa2Cu3O6.95 and which fits well to a model with static magnetic fields in the vortex cores. The magnitude of the fields is estimated to be 18(2) G and decreases above T = 10 K. We discuss possible origins of the additional vortex core magnetism within the context of existing theories.

Low temperature limit of the vortex core radius and the kramer-pesch effect in NbSe2

Muon spin rotation ( &mgr;SR) has been used to measure the magnetic field distribution in the vortex state of the type-II superconductor NbSe2 ( T(c) = 7.0 K) below T = 2 K. The distribution is consistent with a highly ordered hexagonal vortex lattice with a well resolved high-field cutoff associated with the finite size of the vortex cores. The temperature dependence of the core radius is much weaker than the temperature dependence predicted from the Bogoliubov-de Gennes theory. Furthermore, the vortex radius measured by &mgr;SR near the low temperature quantum limit is about an order of magnitude larger than predicted.