The purpose of this project was to identify group differences in physical function and HRQL between older adults living in different environments, and to compare information from these groups to data from a random sample of elders pulled from the general population. METHODS: Seventy-eight older adults were evaluated for physical function using the continuous-scale physical functional performance test (CS-PFP) and HRQL using the SF-36 v.2. Subjects were 26 predominantly African American participants (LOW group; age 72.2 ± 8.1 years), 26 Caucasian adults (HIGH group; age 77.6 ± 4.8 years), and 26 adults selected from a population-based study (POP group; age 73.4 ± 6.4 years). RESULTS: MANCOVA (age as a covariate) revealed group differences in physical function and HRQL. Follow-up LSD comparisons revealed that the LOW group had greater upper body strength compared to both the HIGH and POP groups (61.2 ± 3.7 vs. 43.6 ± 3.6 and 35.4 ± 3.6, respectively), and greater lower body strength (42.2 ± 3.3 vs. 36.5 ± 3.6) and total CS-PFP score (55.5 ± 3.5 vs. 44.4 ± 3.4) than POP. With respect to HRQL, the POP group had poorer SF-36 role physical (RP), physical function (PF), and physical component subscale (PCS) scores than the LOW and HIGH groups (PF: POP = 53.3 ± 5.8, LOW = 76.6 ± 5.3, HIGH = 75.5 ± 5.4; RP: POP = 56.6 ± 6.9, LOW = 80.9 ± 6.4, HIGH = 85.8 ± 6.4; PCS: POP = 38.3 ± 2.1, LOW = 49.6 ± 2.0, HIGH = 48.0 ± 2.0). The LOW had poorer mental health (MH) and mental component subscale (MCS) scores than the HIGH and POP groups (MH: LOW = 69.2 ± 2.6, HIGH = 88.4 ± 2.6, POP = 85.1 ± 2.6; MCS: LOW = 51.5 ± 1.4, HIGH = 57.7 ± 1.5, POP = 58.2 ± 1.6). CONCLUSION: These findings are consistent with the theory that environmental press may interact with functional ability to impact HRQL. Supported by the National Institute on Aging [P01 (AG022064091A1)] and the Louisiana Board of Regents through the Millennium Trust Health Excellence Fund [HEF (2001-06)02].

Aging and age related disease affects individuals differently. One possible explanation could be free radical production varies among individuals and this variation determines the aging process and the progression of disease. The purpose of this study was to test whether nonagenarians have a relatively low metabolic rate when compared to younger individuals and whether this low metabolic rate is associated with lower levels of oxidative stress and less incidence of disease. Resting metabolic rate (RMR), markers of oxidative stress to lipids, proteins, and DNA, components of the metabolic syndrome, and physical activity level were measured in 3 groups of individuals aged 20-34 (16M/25F), 60-74 (16M/11F), and >90y (23M/25F). RMR, adjusted for fat-free mass, fat mass, and sex was significantly lower in both of the older groups when compared to the younger group (p<0.007). Nonagenarians had significantly (p<0.01) lower DNA damage than the middle-aged subjects (60-74y). However, there were also no significant relationship between RMR and any of the markers of oxidative stress. Nonagenarians had less prevalence of the metabolic syndrome than the aged individuals; however, this was not related to reduced levels of oxidative stress. The current study confirms previous findings of an age related decline in RMR adjusted for body weight and body composition. In addition, nonagenarians appeared to be protected from an age-related increase in DNA damage and development of the metabolic syndrome. However, there was no relationship between the level of oxidative damage and RMR challenging the rate of living/ oxidative stress hypothesis.

The purpose of the study was to determine if the body weight support system (BWSS) maintains the targeted percentage of the subject's body weight support (BWS) during walking and to explore the relationship between unloading and ground reaction force. Sixteen healthy college students (mean age: 22 years old) were recruited as subjects. Tests were conducted using an instrumented treadmill with a BWSS. The BWSS harness was secured around the lower abdomen and pelvis of each subject for effective body weight support. Vertical ground reaction force was measured by force platforms embedded in the treadmill. A force sensor was attached to the top of the harness to measure the actual amount of support force being exerted by the BWSS while the subject walked on the treadmill. The subject's body weight was supported at targeted levels of 0%, 15%, 30%, and 45%. Subjects walked at speeds of 0.447, 0.671, 0.894, and 1.117 meters per second for each level of targeted body weight support (TBWS). As speed increased, the maximum support force (SFmax) increased while the minimum support force (SFmin) decreased. As the levels of TBWS increased, the SFmax as well as the SFmin increased. The maximum support force was affected by the different body weight support levels and fluctuated from 5.08% to 11.22% above the TBWS. The minimum support force fluctuated from 0.40% below to 13.05% above the targeted body weight support. The fluctuations were also affected by walking speed. SFmax deviation ranged from 6.12% to 10.03% above TBWS across speeds while the SFmin deviated from 7.06 to 8.58% above TBWS across speeds. As speed increased, maximum ground reaction force also increased. As the levels of BWS increased, the maximum ground reaction force decreased. The BWSS did not sustain the targeted percentage of BWS and actually supported a lesser percentage of the subject's body weight throughout the trials. Vertical ground reaction forces were reduced with the use of the BWSS but were disproportional to the TBWS levels. These findings are important in providing both safe and efficient treatment for future patients in producing maximum benefits in therapy.

The goal of this research was to gain greater understanding about the management of heart failure patients. A particular focus was to evaluate exercise tolerance and behavior. The major findings of the first study included: (1) evidence that few heart failure patients receive adequate information regarding physical activity; (2) performance on a six-minute walk test were ~42% lower, and SF-36 scores were also lower in heart failure patients compared to controls; (3) stability in hemodynamic measures and distance walked on the 6-minute walk test were adequate, and (4) home exercise resulted in 19% improvement in maximum walking distance and 30% improvement in physical function score on the SF-36. The second study showed the feasibility to implement a care-managed program for heart failure patients in a family practice setting. However, a significant barrier was recruitment. Despite this failure, patients improved ~24% on the maximum walking distance and 29%, 46%, and 13% on the physical function, vitality, and mental health scores on the SF-36. The third study examined the motivation and readiness of heart failure patients to engage in planned physical activity. The findings revealed 22 patients in precontemplation, 33 in contemplation, 41 in preparation, 23 in action, and 29 in maintenance. In regards to the Transtheoretical model constructs (self-efficacy, pros and cons of decisional balance, and experiential processes) the data revealed that self-efficacy scores were lowest in the precontemplation and increased in linear fashion to maintenance. Decisional balance changed from greater perceived cons and lower perceived pros in precontemplation and contemplation to lower perceived cons and higher perceived pros in action and maintenance. Experiential processes were used predominantly in precontemplation and contemplation, whereas behavioral processes were more prominently used in action and maintenance. The most important predictors of physical activity stages of change were the behavioral processes (r2= .78)followed by perceived self-efficacy (r2= .66). Finally, this study indicated that patients in preaction stages of readiness to exercise have significant lower exercise tolerance then those in action and maintenance. These data suggest greater clinical emphasis should be placed on strategies to move patients toward the preparation and action stages of readiness.

Analysis of the mechanical and neural regulatory mechanisms of the flexion-relaxation phenomenon (FRP), observed in deep trunk flexion, was performed since it is believed these mechanisms provide insight into the causes of low back injury and pain. Three methods were used to analyze the behavior of the lumbar tissues during trunk flexion-extension exercises: 1) active continuous cyclic movement, 2) acute cyclic movement at different orientations, and 3) passive continuous cyclic movement. All activities were performed at a rate of 0.1 Hz (6 cyclesmin-1) while monitoring the surface electromyography (EMG) of the lumbar paraspinal muscles. Abdominal, hamstring, and quadriceps muscle activities were also monitored during acute cyclic movement. Trunk inclination and lumbar flexion angles were time synchronized with the recorded EMG signals. Increases in the myoelectric silent period with respect to inclination and flexion angles were apparent over time (p < 0.001) during the active continuous cyclic activity. Muscular fatigue and constant gravitational loading of the system were thought to influence the observations. Acute cyclic movements of trunk flexion-extension were performed in standing and supine positions. In standing, abdominal EMG activity increased when silent periods were present in lumbar paraspinal and hamstring muscles. Performance of flexion-extension from the supine position resulted in sustained silence of the paraspianl muscles once gravitational load was presented as the trunk flexed beyond vertical into deep flexion. EMG activity within the paraspinal muscles increased while extension was executed. During passive continuous cyclic movement the trunk motion was controlled by an external mechanical system to isolate the movement from fatigue. A significant decrease in the torque supplied by the posterior passive tissues was observed. EMG amplitudes remained relatively low during the passive session. A significant increase in the EMG amplitude and frequency was observed during active flexion movements performed after the passive session. Evidence suggests the primary control mechanism of the FRP to be mechanical in origin for acute loading. Decrease stability of the spine may occur with prolonged repetitive trunk flexion-extension. The increased duration of the FRP during continuous cyclic flexion-extension suggests neural mechanisms may supersede mechanical mechanisms during repetitive lifting activities.

The relationships between maximal oxygen consumption (VO2max), mitochondrial function and running economy were investigated in a population of twenty-one endurance trained males and females (range=18-54 yrs). The purposes of this study were: 1) to determine whether mitochondrial oxidative capacity, as defined by the maximal activities of citrate synthase (CS), cytochrome c oxidase (COX), and beta-hydroxyacyl-CoA dehydrogenase (BHAD), is a significant determinant of maximal oxygen consumption in endurance trained men and women, and 2) to observe the relationship between maximal oxygen uptake and running economy in the same population. Muscle biopsy samples were taken from the vastus lateralis prior to a 90-minute bout of submaximal running (65% VO2max) from which running economy was assessed. Running economy was observed to significantly negatively correlate with VO2max, expressed in either absolute or relative values: L/min (r = -.506), ml/kg body mass/min (r = -.703) and ml/kg FFM/min (r = -.700). Data also show that maximal COX activity was significantly related to VO2max, L/min (r = .789). In addition, non-significant positive correlations were apparent between both CS and COX activity and all other expressions of VO2max (r > .6). BHAD activity was not related to any measured variable. These results confirm that an inverse relationship is present relating VO2max and running economy. Also, data herein indicate that maximal activities of key marker enzymes of the citric acid cycle and oxidative phosphorylation are likely a significant factor determining whole-body maximal oxygen consumption in endurance trained males and females.

The purpose of this study was to investigate the relationships between self-determination, perceptions of the motivational climate, attitude, perceived ability, engagement in physical activity, and health-related fitness indicators. Two structural models related to engagement/intention to engage in physical activity and health-related fitness were tested. The premise of both models is that perceived competence predicts the outcome variables (engagement or health-related fitness), with self-determination, attitude, and motivational climate predicting perceived competence. Participants were 827 sixth, seventh, and eighth graders. Motivation, perceptions of the climate, attitude, perceived competence, and self-reported physical activity levels were assessed using surveys. Pedometers were used to record steps taken during physical education classes to obtain a quantifiable measure of physical activity. Body mass index and skinfold measures were used to assess body composition, and a measure of cardiovascular endurance was also collected. Perceptions of competence were related to both engagement and health indicators. Engagement and health indicators were also indirectly affected by the motivational climate, where the focus was on learning and mastery. This study suggests that providing a learning climate and structuring the environment so that students can be successful in their physical education endeavors fosters active engagement and is positively associated with health related components of fitness.

Despite the health benefits associated with active lifestyles, a majority of adults do not engage in sufficient levels of physical activity (PA). Few individual-focused interventions have produced sustained changes in PA behavior. Therefore, public health officials are promoting the use of ecological approaches to examine the multidimensional factors that influence choices about PA and other health behaviors. National statistics are mirrored in college populations, with one-half of students in the US failing to meet current PA recommendations and one-third classified as either overweight or obese. In light of this, increasing PA and obesity prevention have been identified as the top two priorities in the national Healthy Campus 2010 initiative. Research suggests that reductions in PA and increases in weight that occur during the freshman year of college and are likely to continue into adulthood are related to social and physical environmental factors. The assessment of physical environmental influences, however, on PA in college populations has been narrow in scope and inherent limitations associated with self-reported height and weight, and BMI as a predictor of obesity in youth exist. The purpose of this study was to implement an ecological model to explore factors that influence PA behaviors of college students, and to examine how those factors related to risk for overweight and obesity. Using a cross-sectional design, 308 university freshmen were surveyed regarding cognitive beliefs about PA, perceptions of neighborhood features, and participation in specific types of PA. Body composition assessments were conducted on 61 volunteers from that sample to examine the reliability and validity of self-reported BMI as an indicator of weight risk. Results suggest that safe community neighborhoods and better land use mix on campus encouraged participation in PA, but were not as predictive of PA behavior as demographic and cognitive factors. Gender and race specific biases in reported height and weight were evident. Only moderate correlations existed between measured BMI and percent body fat, compromising the ability to establish associations between the physical environment, physical activity and risk for obesity. Percentage of body fat may be more useful to establish relationships with environmental influences in this population.

Blood flow distribution relies on the vasculatures ability to vasodilate and vasoconstrict throughout the body. Most previous research has focused on only one of these abilities, either vasodilation or vasoconstriction. For example, Thijssen et al. (2005) focused their research on vasodilation by studying reactive hyperemia, while Kinuyoshi et al. (2003) studied the possible vasoconstriction effect with increasing muscle sympathetic nerve activity. The purpose of this study was to assess vascular function using a variety of stimuli to potentially learn more about overall vascular health, while determining the stability and reliability of blood flow measurements using strain gauge plethysmography. Measures of vascular function were examined in 12 individuals [age=21±1 yrs]. Right lower leg resting arterial inflow, post occlusion reactive hyperemia, dynamic exercise blood flow, and blood flow following a cold stimulus were assessed on two separate occasions. The average resting arterial inflow was 2.27 ± 1.06 ml/100ml/min, reactive hyperemic blood flow was 19.42 ± 6.37 ml/100ml/min, exercise blood flow was 27.37 ± 14.95 ml/100ml/min, and blood flow following a cold stimulus was 1.53 ± 0.89 ml/100ml/min. A rather unique finding was the associations between the stimuli blood flow responses, by which those with the greatest reactive hyperemia blood flow responses also exhibited the greatest exercise blood flows and greatest drop in blood flow following the cold stimulus. In conclusion, the pattern of the blood flow responses and the correlations among the measurements, in addition to being stable and reliable, provide us with a greater understanding of the blood flow distribution properties of the vasculature.

The purpose of this study was to examine college students' motivations to be physically active by merging the perspectives of self-determination theory and the transtheoretical model. The secondary purpose was to examine the effects of a required physical activity course on college students' levels of physical activity. The premise is that both the theory and model can be used to help predict physical activity outcomes. Participants were 277 male and female students at a small private college. Motivation, self-determination, stage of change, self-efficacy, decisional balance, and leisure time activity levels were assessed using an online survey. Results revealed that activity levels did vary across stages of change and that the participants became more self-determined as they moved across the stages of change. Intrinsic motives were predictors of self-determination and motives were found to differ across the stages of change. Decisional balance scores were higher in the later stages of change (maintenance, action, and preparation) while the self-efficacy scores were lower in the early stages (contemplation and precontemplation) than all other stages. No significant group differences were found between students who had or had not completed the physical activity course for RAI, decisional balance, and self-efficacy. However, group differences in motives revealed that interest/enjoyment, competence, and social motives were rated as more important by those who had taken the course than those who had not. There were no differences on self-reported levels of physical activity. Results suggest that currently used approaches in required courses may not be effective in increasing physical activity levels of college students. The incorporation of the transtheoretical model with self-determination theory provides a framework to investigate the motivational levels of college students and could be incorporated in attempts to improve the effectiveness of required courses designed to facilitate their pursuit of a lifetime of physical activity.