Search tips
Search criteria

Results 1-25 (25)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Promoting Physical Activity in Low-Active Adolescents via Facebook: A Pilot Randomized Controlled Trial to Test Feasibility 
JMIR Research Protocols  2014;3(4):e56.
The World Wide Web is an effective method for delivering health behavior programs, yet major limitations remain (eg, cost of development, time and resource requirements, limited interactivity). Social media, however, has the potential to deliver highly customizable and socially interactive behavioral interventions with fewer constraints. Thus, the evaluation of social media as a means to influence health behaviors is warranted.
The objective of this trial was to examine and demonstrate the feasibility of using an established social networking platform (ie, Facebook) to deliver an 8 week physical activity intervention to a sample of low-active adolescents (N=21; estimated marginal mean age 13.48 years).
Participants were randomized to either an experimental (ie, Behavioral) or attentional control (ie, Informational) condition. Both conditions received access to a restricted-access, study-specific Facebook group where the group’s administrator made two daily wall posts containing youth-based physical activity information and resources. Primary outcomes included physical activity as assessed by accelerometry and self-report. Interactions and main effects were examined, as well as mean differences in effect sizes.
Analyses revealed significant improvements over time on subjectively reported weekly leisure-time physical activity (F 1,18=8.426, P=.009, η2 = .319). However, there was no interaction between time and condition (F 1,18=0.002, P=.968, η2 = .000). There were no significant time or interaction effects among the objectively measured physical activity variables. Examination of effect sizes revealed moderate-to-large changes in physical activity outcomes.
Results provide initial support for the feasibility of delivery of a physical activity intervention to low-active adolescents via social media. Whether by employing behavioral interventions via social media can result in statistically meaningful changes in health-related behaviors and outcomes remains to be determined.
Trial Registration NCT01870323; (Archived by WebCite at
PMCID: PMC4259906  PMID: 25357008
social media; physical activity; adolescents; behavior change; randomized controlled trial; feasibility
2.  Improving physical functional and quality of life in older adults with multiple sclerosis via a DVD-delivered exercise intervention: a study protocol 
BMJ Open  2014;4(12):e006250.
There is a need to identify innovative, low-cost and broad-reaching strategies for promoting exercise and improving physical function in older adults with multiple sclerosis (MS).
Methods and analysis
This randomised controlled pilot trial will test the efficacy of a 6-month, DVD-delivered exercise intervention to improve functional performance and quality of life in older adults with MS. Participants will be randomised either into a DVD-delivered exercise condition or an attentional control condition. This novel approach to programme delivery provides participants with detailed exercise instructions which are presented in a progressive manner and includes a variety of modifications to better meet varying levels of physical abilities. The targeted exercises focus on three critical elements of functional fitness: flexibility, strength and balance. It is hypothesised that participants who are randomised to the exercise DVD condition will demonstrate improvements in physical function compared with participants assigned to the attentional control condition. Data analysis will include a 2 (condition)×2 (time) mixed factor analysis of variance (ANOVA) that follows intent-to-treat principles, as well as an examination of effect sizes. Participants will take part in qualitative interviews about perspectives on physical activity and programme participation.
Ethics and dissemination
The study protocol was approved by a university institutional review board and registered with a federal database. Participants will be asked to read and sign a detailed informed consent document and will be required to provide a physician's approval to participate in the study. The exercise DVDs include an overview of safety-related concerns and recommendations relative to exercise participation, as well as detailed instructions highlighting the proper execution of each exercise presented on screen. Following completion of this trial, data will be immediately analysed and results will be presented at scientific meetings and published in scholarly journals.
Trial registration number
Clinical Trials NCT01993095.
PMCID: PMC4256639  PMID: 25448627
3.  The influence of aerobic fitness on cerebral white matter integrity and cognitive function in older adults: Results of a one-year exercise intervention 
Human brain mapping  2012;34(11):2972-2985.
Cerebral white matter degeneration occurs with increasing age and is associated with declining cognitive function. Research has shown that cardiorespiratory fitness and exercise are effective as protective, even restorative, agents against cognitive and neurobiological impairments in older adults. In this study, we investigated whether the beneficial impact of aerobic fitness would extend to white matter integrity in the context of a one-year exercise intervention. Further, we examined the pattern of diffusivity changes to better understand the underlying biological mechanisms. Finally, we assessed whether training-induced changes in white matter integrity would be associated with improvements in cognitive performance independent of aerobic fitness gains. Results showed that aerobic fitness training did not affect group-level change in white matter integrity, executive function, or short-term memory, but that greater aerobic fitness derived from the walking program was associated with greater change in white matter integrity in the frontal and temporal lobes, and greater improvement in short-term memory. Increases in white matter integrity, however, were not associated with short-term memory improvement, independent of fitness improvements. Therefore, while not all findings are consistent with previous research, we provide novel evidence for correlated change in training-induced aerobic fitness, white matter integrity, and cognition among healthy older adults.
PMCID: PMC4096122  PMID: 22674729
Diffusion tensor imaging; Anisotropy; Cerebrum; Cognition; Physical fitness; Aging
4.  Effects of a DVD-Delivered Exercise Intervention on Physical Function in Older Adults 
Given the rapidly increasing demographic of older adults, it is vital to implement effective behavioral strategies to improve physical function to maintain activities of daily living. However, changing physical activity in older adults remains extremely difficult. The current trial tested the efficacy of a novel, 6-month, home-based, DVD-delivered exercise program focusing on flexibility, balance, and toning on the physical function of older adults.
Older adults (N = 307) were recruited from 83 towns and cities throughout central Illinois. The trial consisted of 4 waves of recruitment and randomization from May 2010 through January 2012. Inclusion criteria included being inactive, at least 65 years of age, English speaking, providing physician’s consent, and willingness to be randomized. Eligible participants were randomly assigned to 1 of 2 treatment conditions: the exercise intervention or a healthy aging, attentional control. Functional assessments were completed at baseline and following the 6-month DVD intervention. Measures included the Short Physical Performance Battery, assessments of flexibility and strength, and self-reported functional limitations.
Participants in the DVD intervention condition demonstrated significant improvements in the Short Physical Performance Battery (p = .005), lower extremity flexibility (p = .04), and upper body strength (p = .003). There were no effects of the intervention on self-reported functional limitations.
The exercise intervention produced a clinically significant improvement in the Short Physical Performance Battery and improvements in flexibility and strength, demonstrating the effectiveness of a low-cost DVD exercise program in improving physical function in older adults.
PMCID: PMC3738028  PMID: 23401566
Clinical trial; DVD; Home-based exercise; Functional performance; Public health; Gait; Balance.
5.  Physical Activity and Quality of Life in Older Adults: An 18-Month Panel Analysis 
Although physical activity has been associated with quality of life (QOL), the empirical evidence regarding the mechanisms underlying this relationship is limited. In the present study, we examined the mediating roles played by self-efficacy and health status in the physical activity-QOL relationship from baseline to 18-month follow-up in a sample of community dwelling older adults.
Community dwelling adults (N = 321, M age = 63.8 years) were recruited to participate in a cross-sectional study and were later contacted to participate in an 18 month follow-up. Individuals completed a battery of questionnaires assessing physical activity, self-efficacy, physical self-worth, disability limitations, and quality of life. A panel analysis within a covariance modeling framework was used to analyze the data.
Overall the model was a good fit to the data (χ2 = 61.00, df = 29, p < 0.001, Standardized Root Mean Residual = 0.05, Comparative Fit Index = 0.97) with changes in physical activity indirectly influencing change in life satisfaction from baseline to 18 months via changes in exercise self-efficacy, physical self-worth, and disability limitations independent of baseline relationships and demographic factors. Specifically, increases in physical activity were associated with increases in exercise self-efficacy which, in turn, was associated with higher physical self-worth and fewer disability limitations which were associated with greater life satisfaction.
The findings from this study suggest the relationship between physical activity and global QOL in older adults may be mediated by more proximal modifiable outcomes that can be targeted in physical activity programs and interventions.
PMCID: PMC3625695  PMID: 23161331
physical activity; quality of life; self-efficacy; older adults
6.  The Perceived Importance of Physical Activity: Associations with Psychosocial and Health-Related Outcomes 
The purpose of this study was to assess the extent to which participation in a 12-month exercise program changed the degree of importance that older adults attached to physical activity. Additionally, associations among changes in physical activity importance and health-related and psychosocial outcomes were examined.
Community-dwelling older adults (N = 179) were recruited to participate in a 12-month exercise trial examining the association between changes in physical activity and fitness with changes in brain structure and psychological health. Participants were randomly assigned to a walking condition or a flexibility, toning, and balance condition. Physical, psychological, and cognitive assessments were taken at months 0, 6, and 12.
Involvement in a 12-month exercise program increased the importance that participants placed on physical activity; this positive change was similar across exercise condition and sex. Changes in importance, however, were only associated with changes in physical health status and outcome expectations for exercise midway through the intervention. There were no significant associations at the end of the program.
Regular participation in physical activity can positively influence the perceived importance of the behavior itself. Yet, the implications of such changes on physical activity-related outcomes remain equivocal and warrant further investigation
PMCID: PMC3856648  PMID: 22820124
7.  Influence of allowable interruption period on estimates of accelerometer wear time and sedentary time in older adults 
The criteria one uses to reduce accelerometer data can profoundly influence the interpretation of research outcomes. The purpose of this study was to examine the influence of three different interruption periods (i.e., 20, 30, and 60 minutes) on the amount of data retained for analyses and estimates of sedentary time among older adults. Older adults (N=311; Mage=71.1) wore an accelerometer for seven days and reported wear time on an accelerometer log. Accelerometer data were downloaded and scored using 20, 30, and 60-minute interruption periods. Estimates of wear time derived using each interruption period were compared to self-reported wear time, and descriptive statistics were used to compare estimates of sedentary time. Results showed a longer interruption period (i.e., 60 minutes) yields the largest sample size and the closest approximation of self-reported wear time. A short interruption period (i.e., 20 minutes) is likely to underestimate sedentary time among older adults.
PMCID: PMC3875619  PMID: 23752299
8.  Neurobiological markers of exercise-related brain plasticity in older adults 
The current study examined how a randomized one-year aerobic exercise program for healthy older adults would affect serum levels of brain-derived neurotrophic factor (BDNF), insulin-like growth factor type 1 (IGF-1), and vascular endothelial growth factor (VEGF) - putative markers of exercise-induced benefits on brain function. The study also examined whether (a) change in the concentration of these growth factors was associated with alterations in functional connectivity following exercise, and (b) the extent to which pre-intervention growth factor levels were associated with training-related changes in functional connectivity. In 65 participants (mean age = 66.4), we found that although there were no group-level changes in growth factors as a function of the intervention, increased temporal lobe connectivity between the bilateral parahippocampus and the bilateral middle temporal gyrus was associated with increased BDNF, IGF-1, and VEGF for an aerobic walking group but not for a non-aerobic control group, and greater pre-intervention VEGF was associated with greater training-related increases in this functional connection. Results are consistent with animal models of exercise and the brain, but are the first to show in humans that exercise-induced increases in temporal lobe functional connectivity are associated with changes in growth factors and may be augmented by greater baseline VEGF.
PMCID: PMC3544982  PMID: 23123199
exercise; aging; functional connectivity; fMRI; default mode network; aerobic fitness; growth factors
9.  Functional connectivity: a source of variance in the association between cardiorespiratory fitness and cognition? 
Neuropsychologia  2010;48(5):1394-1406.
Over the next twenty years the number of Americans diagnosed with dementia is expected to more than double (CDC 2007). It is, therefore, an important public health initiative to understand what factors contribute to the longevity of a healthy mind. Both default mode network (DMN) function and increased aerobic fitness have been associated with better cognitive performance and reduced incidence of Alzheimer’s disease among older adults. Here we examine the association between aerobic fitness, functional connectivity in the DMN, and cognitive performance. Results showed significant age-related deficits in functional connectivity in both local and distributed DMN pathways. However, in a group of healthy elderly adults, almost half of the age-related disconnections showed increased functional connectivity as a function of aerobic fitness level. Finally, we examine the hypothesis that functional connectivity in the DMN is one source of variance in the relationship between aerobic fitness and cognition. Results demonstrate instances of both specific and global DMN connectivity mediating the relationship between fitness and cognition. We provide the first evidence for functional connectivity as a source of variance in the association between aerobic fitness and cognition, and discuss results in the context of neurobiological theories of cognitive aging and disease.
PMCID: PMC3708614  PMID: 20079755
cognitive aging; fMRI; functional connectivity; aerobic exercise; executive function; spatial memory
10.  Physical Activity, Function, and Quality of Life: Design and Methods of the FlexToBa™ Trial 
Contemporary Clinical Trials  2011;33(1):228-236.
The Flexibility, Toning, and Balance (FlexToBa™) Trial is a two-armed randomized controlled trial which will contrast the effects of a DVD-delivered, home-based, physical activity intervention and a Healthy Aging attention control condition on physical activity, functional performance, functional limitations, and quality of life in low active, older adults. This innovative trial will recruit 300 participants across central Illinois who will be randomized into the intervention arm or control arm of the study. The intervention will last 6 months with a 6 month follow-up. Assessments at baseline, post intervention and follow-up will include physical activity (self-report and accelerometry), a battery of functional performance measures, functional limitations, quality of life, and an array of psychological health measures. In addition, measures of external validity will be included to determine public health significance of a successful outcome. Participants will engage in a progressive series of activities focusing on flexibility, strengthening, and balance exercises which are demonstrated by a trained exercise leader and age-appropriate models on a series of DVDs. Delivery of the intervention has its basis in social cognitive theory. The specific aims of the trial are (a) to determine the effects of the DVD-delivered FlexToBa™ program on physical activity, functional performance, functional limitations, and quality of life, (b) to examine the mediators of the relationships between physical activity and functional limitations and quality of life, (c) to assess external validity indicators relative to the intervention, and (d) to determine differential effects of the intervention on psychosocial health measures.
PMCID: PMC3253879  PMID: 22024470
Physical activity; older adults; functional limitations; functional performance; quality of life
11.  Social Cognitive Influences on Physical Activity Behavior in Middle-Aged and Older Adults 
The purpose of the current study was to prospectively test the utility of a social cognitive theory (SCT) model of physical activity behavior over an 18-month period in middle-aged and older adults (N = 321; M age = 63.8 years).
Participants completed measures of self-efficacy, disability limitations, goals, outcome expectations, and physical activity at baseline and follow-up. Self-efficacy was hypothesized to influence physical activity both directly and indirectly through goals and outcome expectations. Relationships were examined using panel analysis within a covariance modeling framework.
The model provided an excellent fit to the data (χ2 = 36.16, df = 30, p = .20; comparative fit index = 1.00; root mean square error of approximation = .03). At baseline, self-efficacy was directly related to outcome expectations, disability limitations, goals, and physical activity and indirectly related to physical activity through physical outcome expectations. Changes in self-efficacy were significantly related to residual changes in outcome expectations, disability limitations, goals, and physical activity and indirectly related to residual changes in physical activity through changes in physical and social outcome expectations.
These results provide further support for the use of SCT to physical activity behavior in middle-aged and older adults. Self-efficacy influenced physical activity both directly and indirectly via outcome expectations, suggesting that these variables should be targeted in physical activity interventions for middle-aged and older adults.
PMCID: PMC3410683  PMID: 21743038
Middle aged; Older adults; Physical activity; Social cognitive theory
12.  Growth Trajectories of Exercise Self-Efficacy in Older Adults: Influence of Measures and Initial Status 
This study examines differential trajectories of exercise-related self-efficacy beliefs across a 12-month randomized controlled exercise trial.
Previously inactive older adults (N = 144; M age = 66.5) were randomly assigned to one of two exercise conditions (walking, flexibility-toning-balance) and completed measures of barriers self-efficacy (BARSE), exercise self-efficacy (EXSE), and self-efficacy for walking (SEW) across a 12-month period. Changes in efficacy were examined according to efficacy type and inter-individual differences. Latent growth curve modeling was employed to (a) examine average levels and change in each type of efficacy for the collapsed sample and by intervention condition, and (b) explore subpopulations (i.e., latent classes) within the sample that differ in their baseline efficacy and trajectory.
Analyses revealed two negative trends in BARSE and EXSE at predicted transition points, in addition to a positive linear trend in SEW. Two subgroups with unique baseline efficacy and trajectory profiles were also identified.
These results shed new light on the relationship between exercise and self-efficacy in older adults, and highlight the need for strategies for increasing and maintaining efficacy within interventions, namely targeting participants who start with a disadvantage (lower efficacy) and integrating efficacy-boosting strategies for all participants prior to program end.
PMCID: PMC3521039  PMID: 21038962
exercise; self-efficacy; trajectories of change; aging
13.  Cardiorespiratory Fitness, Hippocampal Volume and Frequency of Forgetting in Older Adults 
Neuropsychology  2011;25(5):545-553.
The purpose of this study was to extend our earlier work to determine the extent to which cardiorespiratory fitness is associated with the frequency of memory problems via its effects on the hippocampus and spatial working memory. We hypothesized that age, sex, education, body composition, and physical activity were direct determinants of fitness which, in turn, influenced frequency of forgetting indirectly through hippocampal volume and spatial working memory.
We conducted assessments of hippocampal volume, spatial working memory, frequency of forgetting, BMI, physical activity, demographic characteristics, and cardiorespiratory fitness in 158 older adults (M age = 66.49). Path analyses within a covariance modeling framework were used to examine relationships among these constructs.
Sex, age, BMI, and education were all significant determinants of cardiorespiratory fitness. The hypothesized path models testing the effects of fitness on frequency of forgetting through hippocampal volume and accuracy and speed of spatial working memory all fit the data well.
Our findings suggest that older adults with higher levels of fitness show greater preservation of hippocampal volume which, in turn, is associated with more accurate and faster spatial memory and fewer episodes of forgetting. Given the proportion of older adults reporting memory problems, it is necessary to determine whether improvements in fitness brought about by physical activity interventions can result in subsequent attenuation of memory problems or potentially improvements in memory.
PMCID: PMC3140615  PMID: 21500917
Frequency of Forgetting; Hippocampus Volume; Cardiorespiratory Fitness; Spatial Memory; Older Adults
14.  Self-Regulatory Processes and Exercise Adherence in Older Adults 
Self-efficacy and the use of self-regulatory strategies are consistently associated with physical activity behavior. Similarly, behavioral inhibition and cognitive resource allocation, indices of executive control function, have also been associated with this health behavior.
The purpose of this study was to examine the hypothesis that self-efficacy mediates the relationship between self-regulatory processes, such as executive function, and sustained exercise behavior.
Older adults (N = 177, mean age = 66.44 years) completed measures of executive function, self-reported use of self-regulatory strategies and self-efficacy prior to and during the first month of a 12-month exercise intervention. Percentage of exercise classes attended over the following 11 months was used to represent adherence. Data were collected from 2007 to 2010 and analyzed in 2010–2011. Structural equation models were tested examining the effect of executive function and strategy use on adherence via efficacy.
As hypothesized, results showed significant direct effects of two elements of executive function and of strategy use on self-efficacy and of efficacy on adherence. In addition, there were significant indirect effects of strategy use and executive function on adherence via self-efficacy.
Higher levels of executive function and use of self-regulatory strategies at the start of an exercise program enhance beliefs in exercise capabilities, which in turn leads to greater adherence.
PMCID: PMC3160622  PMID: 21855742
15.  Trajectories of change in self-esteem in older adults: exercise intervention effects 
Journal of behavioral medicine  2011;34(4):298-306.
This 12-month, 2 arm, single blind randomized controlled exercise trial examined relationships among changes in multidimensional self-esteem as a function of intervention mode (i.e., walking vs. flexibility-toning-balance). Data were collected on three equidistant occasions (baseline, 6 and 12 months). One-hundred seventy-nine older adults (Mage = 66.38) began the study and 145 completed assessments at all time points. Participants completed measures of physical and global self-esteem as well as demographic information. There were no significant group differences at baseline on these demographic indicators or esteem variables. Data were analyzed using linear and parallel process growth modeling procedures. Results supported the position that across both groups, domain-level (i.e., physical self-worth) was dependent upon sub-domain-level (i.e., perceived attractiveness, strength, and condition) esteem change. Furthermore, greater improvements were observed in the flexibility-toning-balance group, in terms of perceived strength and attractiveness esteem, compared to the walking group. Our findings support theoretically-based predictions and extend the literature showing unique psychological responses conditional on specific types of physical activities.
PMCID: PMC3118401  PMID: 21222223
Self perceptions; Physical activity; Growth models; Modes of exercise
16.  Non-Exercise Estimated Cardiorespiratory Fitness: Associations with Brain Structure, Cognition, and Memory Complaints in Older Adults 
There is increasing evidence that cardiorespiratory fitness (CRF) is associated with brain structure and function, and improvements in CRF through exercise training have been associated with neural and cognitive functioning in older adults. The objectives of this study were to validate the use of a non-exercise estimate of CRF, and to examine its association with cognitive function, brain structure and subjective memory complaints. Low active, older adults (N = 86; M age= 65.14) completed a physician-supervised maximal exercise test, a 1-mile timed walk, several measures of cognitive function, and a 3 Tesla structural MRI. Fitness was also calculated from an equation derived by (Jurca et al., 2005) based on age, sex, body mass index, resting heart rate, and self-reported physical activity level. Analyses indicated that all three measures of CRF were significantly correlated with one another. In addition, measures of cognitive function, hippocampus volume, and memory complaints were significantly correlated with each measure of fitness. These findings have implications for using a low-risk, low-cost, non-exercise estimate of CRF in determining fitness associations with brain structure and cognitive function in older adults. As such, this measure may have utility for larger population based studies. Further validation is required, as is determination of whether such relationships hold over the course of exercise interventions.
PMCID: PMC3146052  PMID: 21808657
Equation-derived CRF; cognitive function; hippocampus; older adults
17.  Measuring enjoyment of physical activity in older adults: invariance of the physical activity enjoyment scale (paces) across groups and time 
The purpose of this study was to validate the Physical Activity Enjoyment Scale (PACES) in a sample of older adults. Participants within two different exercise groups were assessed at two time points, 6 months apart. Group and longitudinal invariance was established for a novel, 8-item version of the PACES. The shortened, psychometrically sound measure provides researchers and practitioners an expedited and reliable instrument for assessing the enjoyment of physical activity.
PMCID: PMC3206413  PMID: 21951520
18.  Aerobic Fitness is Associated With Hippocampal Volume in Elderly Humans 
Hippocampus  2009;19(10):1030-1039.
Deterioration of the hippocampus occurs in elderly individuals with and without dementia, yet individual variation exists in the degree and rate of hippocampal decay. Determining the factors that influence individual variation in the magnitude and rate of hippocampal decay may help promote lifestyle changes that prevent such deterioration from taking place. Aerobic fitness and exercise are effective at preventing cortical decay and cognitive impairment in older adults and epidemiological studies suggest that physical activity can reduce the risk for developing dementia. However, the relationship between aerobic fitness and hippocampal volume in elderly humans is unknown. In this study, we investigated whether individuals with higher levels of aerobic fitness displayed greater volume of the hippocampus and better spatial memory performance than individuals with lower fitness levels. Furthermore, in exploratory analyses, we assessed whether hippocampal volume mediated the relationship between fitness and spatial memory. Using a region-of-interest analysis on magnetic resonance images in 165 nondemented older adults, we found a triple association such that higher fitness levels were associated with larger left and right hippocampi after controlling for age, sex, and years of education, and larger hippocampi and higher fitness levels were correlated with better spatial memory performance. Furthermore, we demonstrated that hippocampal volume partially mediated the relationship between higher fitness levels and enhanced spatial memory. Our results clearly indicate that higher levels of aerobic fitness are associated with increased hippocampal volume in older humans, which translates to better memory function.
PMCID: PMC3072565  PMID: 19123237
aging; MRI; spatial memory; cognition; brain
19.  Trajectory of Declines in Physical Activity in Community-Dwelling Older Women: Social Cognitive Influences 
Studies examining physical activity behavior suggest that activity levels decline with age. Such declines are particularly problematic among older adults in light of the research suggesting a protective effect of physical activity on numerous physical health outcomes associated with independent living. Despite a growing recognition of the importance of a physically active lifestyle, little is known about the role of demographic and psychosocial variables on this trajectory of change. In this study, the roles played by outcome expectations, self-efficacy, and functional limitations on changes in physical activity levels over a 2-year period in older women were assessed using latent growth curve modeling. Data were obtained from 249 community-dwelling older women (M age = 68.12, n = 81 Black, and n = 168 White). Demographic, health status, and psychosocial data were collected via self-report upon entry into the study. Self-reported physical activity was assessed at baseline and again at 12 and 24 months. As expected, physical activity declined over the 2-year period. Self-efficacy demonstrated an indirect association with the trajectory of decline in physical activity through functional limitations. Importantly, the pattern of relationships appears independent of demographic factors and chronic health conditions.
PMCID: PMC2728090  PMID: 19528360
Physical activity; Social cognitive; Women
20.  Pathways from Physical Activity to Quality of Life in Older Women 
In spite of consistent evidence to suggest that being more physically active is associated with enhanced quality of life (QOL), there have been remarkably few attempts to determine the possible underlying mechanisms in this relationship.
To prospectively examine the roles played by self-efficacy and physical and mental health status in the physical activity and quality of life relationship in older women.
Older women (M age = 68.12 years) completed measures of physical activity, self-efficacy relative to balance, mental and physical health status, and global QOL at baseline (N = 249) and 24-month follow-up (N = 217). Demographics and general health information were assessed at baseline. A panel analysis within a covariance modeling framework was used to analyze the data.
Analyses indicated that changes in physical activity over time were associated with residual changes in self-efficacy. Changes in self-efficacy were significantly associated with residual changes in physical and mental health status. Only changes in mental health status were significantly related to residual changes in global QOL.
Results from this study support the role of self-efficacy in the relationship between physical activity and QOL. Future physical activity promotion programs should include strategies to enhance self-efficacy for physical activity to be most effective for this population.
PMCID: PMC2846532  PMID: 18677453
21.  Construct validation of a non-exercise measure of cardiorespiratory fitness in older adults 
BMC Public Health  2010;10:59.
Cardiorespiratory fitness (CRF) is associated with a decreased risk of all-cause mortality but is rarely assessed in medical settings due to burdens of time, cost, risk, and resources. The purpose of this study was to test the construct validity of a regression equation developed by Jurca and colleagues (2005) to estimate CRF without exercise testing in community dwelling older adults.
Participants (n = 172) aged 60 to 80 years with no contraindications to submaximal or maximal exercise testing completed a maximal graded exercise test (GXT) and the submaximal Rockport 1-mile walk test on separate occasions. Data included in the regression equation (age, sex, body mass index, resting heart rate, and physical activity) were obtained via measurement or self-report. Participants also reported presence of cardiovascular conditions.
The multiple R for the regression equation was .72, p < .001 and CRF estimated from this equation was significantly correlated with the MET value from the GXT (r = 0.66) and with CRF estimated from submaximal field testing (r = 0.67). All three CRF indices were significantly and inversely associated with reporting more cardiovascular conditions.
This research provides preliminary evidence that a non-exercise estimate of CRF is at least as valid as field test estimates of CRF and represents a low-risk, low-cost, and expedient method for estimating fitness in older adults.
PMCID: PMC2831835  PMID: 20144197
22.  Plasticity of Brain Networks in a Randomized Intervention Trial of Exercise Training in Older Adults 
Research has shown the human brain is organized into separable functional networks during rest and varied states of cognition, and that aging is associated with specific network dysfunctions. The present study used functional magnetic resonance imaging (fMRI) to examine low-frequency (0.008 < f < 0.08 Hz) coherence of cognitively relevant and sensory brain networks in older adults who participated in a 1-year intervention trial, comparing the effects of aerobic and non-aerobic fitness training on brain function and cognition. Results showed that aerobic training improved the aging brain's resting functional efficiency in higher-level cognitive networks. One year of walking increased functional connectivity between aspects of the frontal, posterior, and temporal cortices within the Default Mode Network and a Frontal Executive Network, two brain networks central to brain dysfunction in aging. Length of training was also an important factor. Effects in favor of the walking group were observed only after 12 months of training, compared to non-significant trends after 6 months. A non-aerobic stretching and toning group also showed increased functional connectivity in the DMN after 6 months and in a Frontal Parietal Network after 12 months, possibly reflecting experience-dependent plasticity. Finally, we found that changes in functional connectivity were behaviorally relevant. Increased functional connectivity was associated with greater improvement in executive function. Therefore the study provides the first evidence for exercise-induced functional plasticity in large-scale brain systems in the aging brain, using functional connectivity techniques, and offers new insight into the role of aerobic fitness in attenuating age-related brain dysfunction.
PMCID: PMC2947936  PMID: 20890449
exercise; aging; functional connectivity; fMRI; default mode network; executive function; aerobic fitness
23.  Cardiorespiratory Fitness and Attentional Control in the Aging Brain 
A growing body of literature provides evidence for the prophylactic influence of cardiorespiratory fitness on cognitive decline in older adults. This study examined the association between cardiorespiratory fitness and recruitment of the neural circuits involved in an attentional control task in a group of healthy older adults. Employing a version of the Stroop task, we examined whether higher levels of cardiorespiratory fitness were associated with an increase in activation in cortical regions responsible for imposing attentional control along with an up-regulation of activity in sensory brain regions that process task-relevant representations. Higher fitness levels were associated with better behavioral performance and an increase in the recruitment of prefrontal and parietal cortices in the most challenging condition, thus providing evidence that cardiorespiratory fitness is associated with an increase in the recruitment of the anterior processing regions. There was a top-down modulation of extrastriate visual areas that process both task-relevant and task-irrelevant attributes relative to the baseline. However, fitness was not associated with differential activation in the posterior processing regions, suggesting that fitness enhances attentional function by primarily influencing the neural circuitry of anterior cortical regions. This study provides novel evidence of a differential association of fitness with anterior and posterior brain regions, shedding further light onto the neural changes accompanying cardiorespiratory fitness.
PMCID: PMC3024830  PMID: 21267428
cardiorespiratory fitness; Stroop task; cognitive and attentional control
24.  Assessing Outcome Expectations in Older Adults: The Multidimensional Outcome Expectations for Exercise Scale 
Outcome expectations, an important element of social cognitive theory, have been associated with physical activity in older adults. Yet, the measurement of this construct has often adopted a unidimensional approach. We examined the validity of a theoretically consistent three-factor (physical, social, and self-evaluative) outcome expectations exercise scale in middle-aged and older adults (N = 320; M age = 63.8). Participants completed questionnaires assessing outcome expectations, physical activity, self-efficacy, and health status. Comparisons of the hypothesized factor structure with competing models indicated that a three-factor model provided the best fit for the data. Construct validity was further demonstrated by significant association with physical activity and self-efficacy and differential associations with age and health status. Further evidence of validity and application to social cognitive models of physical activity is warranted.
PMCID: PMC2654993  PMID: 19181688
Outcome expectations; Exercise; Older adults
25.  Physical activity and quality of life in community dwelling older adults 
Physical activity has been consistently associated with enhanced quality of life (QOL) in older adults. However, the nature of this relationship is not fully understood. In this study of community dwelling older adults, we examined the proposition that physical activity influences global QOL through self-efficacy and health-status.
Participants (N = 321, M age = 63.8) completed measures of physical activity, self-efficacy, global QOL, physical self worth, and disability limitations. Data were analyzed using covariance modeling to test the fit of the hypothesized model.
Analyses indicated direct effects of a latent physical activity variable on self-efficacy but not disability limitations or physical self-worth; direct effects of self-efficacy on disability limitations and physical self worth but not QOL; and direct effects of disability limitations and physical self-worth on QOL.
Our findings support the role of self-efficacy in the relationship between physical activity and QOL as well as an expanded QOL model including both health status indicators and global QOL. These findings further suggest future PA promotion programs should include strategies to enhance self-efficacy, a modifiable factor for improving QOL in this population.
PMCID: PMC2649048  PMID: 19200385

Results 1-25 (25)