This is a series of 3 experiments in the area of vasoreactivity. The first study investigated the stability and reproducibility of brachial artery flow-mediated dilation (BAFMD). Twenty-six healthy volunteers underwent 3 scans on 2 days, performed by 2 ultrasonographers, and analyzed by 2 readers. All subjects were tested between 7 and 11am after refraining from food and exercise. Average baseline diameter was 3.48±0.53mm, which increased to 3.71±0.57mm (6.58±4.15%) at peak dilation. ICCC's for days, testers and readers were 0.9188, 0.9394, and 0.8982 respectively. To detect a difference in vasoreactivity of 60% (two-tailed), e.g. 5% vasodilation versus 8% vasodilation, at 90% power, 23 and 10 subjects would be required for cross-sectional and pre-post designs, respectively. These data indicate adequate stability and reproducibility of the BAFMD technique under controlled conditions. The second study investigated the relation between BAFMD and normal plasma fibrinogen (PF) in 30 non-smoking, healthy, volunteers (41±12 yr.; range:22-57). Results indicated a 6.08% increase (range:-3.58 to 17.48%) in BAFMD. Correlation analysis indicated significant inverse relationships for BAFMD and age r=-0.417 (p=0.02), and for BAFMD and PF r=-0.56 (p=0.001). Stepwise multiple regression including PF, age, total cholesterol and blood pressure revealed PF as the predominant predictor for BAFMD with 31% of the variance accounted for by BAFMD =22.61-(0.05836*PF), with no other variables entered. The final study examined the time-course of changes in BAFMD in response to a localized exercise training protocol. Fourteen healthy males (age: 26±5.7) underwent BAFMD assessment prior to, during and following 4 weeks (5 days per week) of 60% maximal voluntary contraction handgrip training of the non-dominant arm. Following training, paired t-tests revealed a 62% increase in BAFMD for the trained arm (6.2±3.0% to 10±4.1%), compared to baseline (p=0.0004), and a 100% difference (10±4.1% vs. 4.6±4.4%) between arms (p=0.0001). An increase in BAFMD (6.2±3.0% to 8.25±2.4%), was evident following 4 days of training (p=0.015), although individual participant variability reduced the statistical power of these findings. There were no changes in hemodynamic, autonomic and hematological variables, suggesting the improvement was a locally mediated process.

Muscular activity and coordination may be influenced by movement speed and the inertial properties of the limbs. Some observed effects from investigations using cycling have been attributed to inertia, especially at greater pedaling speeds (cadences); however, in these investigations, movement speed and inertia were coupled. Therefore, the purpose of this experiment was to investigate and distinguish between the effects of cadence and inertial influences on lower extremity neuromuscular coordination during cycling. This was achieved by subjects cycling at different cadences and with different loads attached to the distal ends of their thighs. Electromyographic (EMG) data of seven lower extremity muscles were collected from sixteen university-aged males cycling at 250 W across three pedaling cadences (60, 80, and 100 rpm) and five loads (0, 0.5, 1.0, 1.5, and 2.0 kg). Onset, offset, duration, peak magnitude, and peak timing values from the EMG linear envelopes were calculated, as were cross-correlation coefficients and phase differences. Results showed that cadence manipulations affected the timing values of the muscles and the coordination of mono- and bi-articular antagonist pairs. Altering the inertial properties of the thigh produced changes only in peak magnitudes. These results led to the conclusion that movement speed effects have a greater influence on the lower extremity muscles during cycling than do inertial effects.

The aim of this study was to test short-term and long-term reliability of venous outflow (VO) indices using the venous occlusion plethysmography technique. A secondary purpose was to compare venous measures to age, gender and various anthropometrical measures. The study group consisted of apparently healthy males and females, aged 18 to 80 years. Venous indices were under measures on two occasions (1 week apart), under the conditions of rest and following 5 min of upper arm occlusion. Venous outflow measures were calculated from the area under the curve (AUC) as well as the plethysmographic curve technique at the time .5 (VO.5), 2 (VO2) and the time interval between .5-2 seconds (VO.5-2). Venous capacitance (VC) was calculated by measuring the distance in mm from the baseline to the maximum height of the inflow curve and dividing this distance by the height of the calibration mark. Intraclass correlation coefficient (ICC) revealed higher within-day reliability than one-week reliability for markers: ICCs = .931 vs. .622, .948 vs. .709, .965 vs. .518, and .971 vs. .431 for VC, VO.5, VO2 and VO.5-2, respectively. One-week reliability for these measures following occlusion were: ICCs = .562, .701, .646 and .639 for all indices. Pearson correlation revealed associations between VO.5 and VO2 with arm length (R= -.344, p< .09; R= -.430, p< .03), respectively. Age was associated with VO.5-2 (R = -.340, p< .10). In addition, there were gender differences in VC (p< .009). Finally, a stepwise regression analysis was performed showing significant predictive value of venous measures, with respect to body size, in arm length (F= 4.979, p< .03) and gender (F= 7.862, p< .01). Short-term VO measures showed stronger reliability than long-term measures. Additionally, it appears that vessel length and gender have an important influence on venous outflow.

The purpose of this thesis was to examine the associations between perceived quality of life (QOL)and self-report and performance-based measures of function. An additional purpose of this thesis was to determine whether the afore-mentioned tests could differentiate between independent-living and assisted-living older adults. A total of 36 residents, independent-living (n=22) and assisted-living (n=14), of a continuing care retirement community (age range=65-94) completed the study. Perceived QOL was assessed using the SF-36 and Nottingham Health Profile. The Barthel Index and Functional Status Index (FSI) were used to assess Activities of Daily Living (ADLs). Physical function was measured using the reduced Continuous Scale-Physical Functional Performance test (CS-PFP 10). Test/retest data (n=10) revealed good stability of the CS-PFP 10 items (ICCs=0.91-0.99). There were significant associations with age and both ADLs and the CS-PFP 10 composite score. There were also significant associations with dwelling status and both the individual tasks and composite score of the CS-PFP 10 and ADLs, but not with perceived QOL (except for NHP-PM). The "scarves" and composite score of the CS-PFP 10 were related to the physical composite score of the SF-36 (p<.005). In addition, the FSI pain and difficulty indicators were also closely asssociated with the SF-36 PCS score (p<.05). Multiple regression of these predictors on the SF-36 PCS score revealed that the "scarves" and FSI pain indicator items provide a strong model of the PCS component of the SF-36 (F=9.51, p<.001). The results of this investigation suggest that the combination of objective and subjective measures of function are associated with the perceived physical aspects of QOL in older adults.

Often the approach to investigating muscular coordination during transitions entailed conducting tests at speeds held constant. This study investigated muscular activity during continuously changing speeds in order to further detail and quantify neuromuscular changes during gait transitions. Twelve healthy adults, 18-41 years of age, were recruited as participants. Informed consent was obtained. Gait transitions were induced by the speed of the treadmill changing with constant acceleration. Reflective markers were placed on anatomical landmarks of the hip, knee,ankle, heel, and 5 th metatarsal joint. Bipolar surface electrodes were positioned on the subjectsskin over the muscular bellies of the gluteus maximus (GM), rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), gastrocnemius (GAS), and soleus (SOL). Electromyographic (EMG) data were collected at 960 Hz. Five transition trials were conducted for both progression modes: walk-to-run (WR) and run-to-walk (RW), and five interval trials were collected for both gaits at constant speeds. Five steps preceding the gait transitions were analyzed. The mean of recorded transition speeds (MTS) was calculated from the prior transition trials. There were five different constant speed trials for walking (WC) and running (RC); the speeds were MTS - 0.6, MTS - 0.3, MTS, MTS + 0.3, and MTS + 0.6 mph. Cross-correlation comparisons and discrete parameters of the EMG activity ensemble curves were examined across trials and conditions. Two factor (condition and trial) repeated measures ANOVA was employed for statistical analysis (á = .05). For the correlation parameters, significant running condition/trial interactions were observed for all muscles. Significant condition/trial interactions were revealed for the discrete parameters concerning activation magnitude (GM, RF, VL, TA, GAS, and SOL)and duration (RF, GAS, and SOL) for both walking and running. EMG activity intensity and duration in some muscles changed with the locomotion speed in a quadratic fashion, which was only observed in transition related trials. These results indicate that neuromuscular changes occurred steps before the observed gait transition and that changing velocity induces gait transition related behavior that cannot be observed with constant velocity in the same range.

The purpose was to examine the cardiovascular response to an acute bout of handgrip exercise before and after non-dominant arm exercise training. 19 people participated in 16 sessions of exercise training and 16 participants acted as controls (age: 20±1yrs). Blood flow measurements were taken at rest and following 3-min of forearm occlusion (RHBF) using plethysmography. Pneumotachometer, ECG, and blood pressure data were continuously collected during three testing conditions (spontaneous breathing (SB1: 5min), handgrip exercise (0.5hz) at 60%MVC with 50mmHg of pressure on the arm (H60+50mmHg: 5 min), and forearm occlusion (FAO: 3min)). Data were analyzed for respiratory rate, mean R-R interval, standard deviation of normal RR intervals (SDNN), normalized units of low- (0-0.15 hz) frequency power (LFnu), and mean arterial pressure (MAP). There was no main effect of group or arm. There was a main effect of test condition such that respiratory rate (+3.10±5.40breaths/min), LFnu (+19.06±14.73%), and MAP increased (+24.51±21.15mmHg) and mean R-R (-247.11±129.70msec) and SDNN (-45.16±40.65msec) decreased significantly during H60+50mmHg (non-dominant arm; p<0.05). Respiratory rate (-0.10±4.84breaths/min), SDNN (-9.50±57.14msec), and LFnu (-1.64±18.34%) recovered to SB1 levels during. Mean R-R (46.11±106.57msec) and MAP (16.65±15.84mmHg) remained elevated above SB1 (p<0.05). There were positive linear associations between forearm circumference and Mean R-R and MAP during H60+50mmHg; and MAP during FAO. There was a negative linear association with forearm circumference and Mean R-R during FAO. There was no significant main effect or interaction with handgrip exercise training on any of the variables. There was a decrease in vascular resistance during RHBF (0.80±1.08 mmHg/ ml/100ml/min, p<0.05) in the arm that underwent exercise training. In conclusion, we found elevated MAP during FAO, which is indicative of significant EPR activity during exercise. Uniquely, we found linear associations between forearm circumference and the cardiovascular response to H60+50mmHg and FAO suggesting variation in the predominant mechanism of cardiovascular control. We did not see an attenuation of cardiovascular responses to H60+50mmHg and FAO with exercise training. However, we did see a decrease in forearm vascular resistance during the reactive hyperemia condition in the exercise-trained arm.

Falls and the fall-related psychological concerns associated with these events pose a serious public health problem among aging adults. Fall-related psychological instruments can be useful in quantifying important endpoints for fall prevention programs (Jorstad et al., 2005), yet no research currently exists to justify the use of these psychological instruments in a community-based falls risk screening. Therefore, the purpose of this dissertation was to examine the psychometric properties of several fall-related psychological measures in a falls risk screening context by: (a) examining the reliability and validity of the Falls Efficacy Scale-International (FES-I), Activities-specific Balance Confidence (ABC), modified Survey of Activities and Fear of Falling in the Elderly (mSAFFE), and Consequences of Falling (CoF) instruments, and (b) testing the sensitivity of one fall-related psychological instrument over a 12-month period in a sample of independent-living older adults. For study one, participants were 133 independent-living older adults between the ages of 51 and 95 years (M age = 74.4 yr, SD = 9.4) from nine community facilities who participated in a falls risk screening. Results from study one revealed that the FES-I, ABC, mSAFFE, and CoF were significantly moderately to strongly correlated with each other, health-related quality of life, and mobility, and demonstrated adequate internal consistency reliability. Further, results showed that only the ABC and the mSAFFE were moderately correlated with physical activity, and only the ABC could differentiate between fallers and non-fallers. Study one results also revealed that the ABC explained the most variance in total falls risk score as compared to the other measures. For study two, participants were 22 independent-living older adults between the ages of 55 and 92 (M age = 74.2 yr, SD = 11.3) who participated in two falls risk screenings over an approximate 12-month period. Results from study two revealed that the ABC was not sensitive to change in a falls risk screening context, U = 45.0, p = .52. Collectively, findings from the dissertation studies can be used to help researchers select the appropriate fall-related psychological instrument for use in a community-based falls risk screening context.

Impaired lipid metabolism at rest has been linked to the development of insulin resistance and an attenuation of plasma concentration of the hormone adiponectin. However, it has been suggested that increasing fatty acid oxidation at rest, via exercise or otherwise, may augment plasma adiponectin. The current literature addressing changes substrate utilization and possible direct effects on adiponectin during and following exercise is not well established. Therefore, the purpose of this dissertation was to examine concomitant changes in adiponectin and substrate utilization both at rest and during various exercise modalities, as this may provide implications for improving metabolic responses and in turn, affect insulin sensitivity. Pre-, mid-, and post-exercise measurements were obtained for five separate studies. Each study incorporated a single, unique exercise modality, which included: acute aerobic, chronic aerobic, acute resistance, chronic resistance, or acute stretching exercise. Chronic resistance training significantly increased adiponectin levels, although resting substrate utilization did not significantly change pre- to post-exercise. All acute exercise modalities significantly increased glucose utilization during exercise. However, none of the acute exercise modalities nor the chronic aerobic exercise modality elicited significant changes in adiponectin. First degree family history of type 2 diabetes mellitus had a significant inverse correlation with adiponectin concentration, whereas regular aerobic exercise had a significant direct correlation with adiponectin. Body fat percentage and body mass index did not have significant inverse correlations with adiponectin. These results suggest that substrate utilization does not directly affect adiponectin concentration and that the regulation of this hormone is likely dependent on other factors. The results do, however, highlight the importance of implementing a chronic exercise training program to limit the development of insulin resistance, especially in populations genetically predisposed to type 2 diabetes mellitus.

Research suggests that elevated serum concentrations of 25-hydroxyvitamin D (25OHD) are associated with slowing the development of many age-related chronic diseases. Recent reports also show a positive relationship between 25OHD and muscle synthesis, strength, power and decreased body fat in elderly individuals. However, these findings have not been consistently reported in younger, healthy populations. PURPOSE: To investigate the relationship between 25OHD levels, body composition, measures of aerobic fitness and muscular strength and power in a young, physically active population. METHODS: Thirty-nine active subjects (20 males, 19 females; 23 ± 0.7 years old) reported to the lab six times for testing. Blood was drawn and 25OHD concentrations were determined using an enzyme-linked immunosorbent assay (ELISA). Primary outcomes included: body composition (dual-energy x-ray absorptiometry, DXA); resting metabolic rate; maximal oxygen uptake (VO2max); power output (Wingate); and strength (eight repetition maximum of bench press, upright row and leg extension and flexion). Primary analysis included all participants, and sub-group analyses on those individuals considered to have sub-optimal serum 25OHD (< 35 ng/mL); LOW (n = 20, 25.97 ± 1.97 ng/mL) and adequate levels of 25OHD (< 35 ng/mL) HIGH (n =19, 44.15 ± 2.17 ng/mL). RESULTS: Half of the subjects (n = 20) exhibited less than optimal 25OHD status, due in part to lack of dietary intake. HIGH males had significantly higher VO2max values when compared to LOW males (p < 0.01). CONCLUSION: A high percentage of college-aged male and female individuals may not be consuming enough vitamin D and aerobic fitness may also be linked to vitamin D status.

Triathlon is an increasingly popular sport in which an athlete competes in swimming, biking and running in a single competitive bout. Today there are more than 140,000 members in the sanctioning body for triathlon. However, there is little descriptive data about this group of athletes. PURPOSE: The primary purpose of this exploratory study was to describe the demographics, training habits, nutritional practices, injury occurrence and overall health status of triathletes and identify any differences between two studies that collected this information. The secondary purpose was to examine any significant correlations among the major outcome variables in the LSU study. METHODS: Three hundred and eighty male and female triathletes were recruited for this study. Participants were recruited at race expos the day prior to the event. Subjects completed a 30-question survey examining triathlete characteristics. The Purdue study surveyed 514 athletes competing in triathlons during the 1999 season. Independent t-tests were conducted to compare variables between studies and genders. Pearsons correlations were run to examine relationships between outcome variables. RESULTS: In the LSU study 248 male and 131 female were recruited, while 367 males and 147 females were recruited in the Purdue study. Mean age of the LSU study participants was 38.5 ± 10.0 years (mean ± SD), while mean age of the Purdue study participants was 33.2 ± 8.9 years. Triathletes in the LSU study report participating in 5.34 ± .3.8 months of competition in the past year, while triathletes in the Purdue study report participating 3.4 ± 2.7 months of competition. Athletes in the LSU study did not meet daily recommendations for carbohydrates, with only 12.6% of triathletes in the LSU study meeting requirements. The most common injury suffered, at the knee, occurred in 34% of triathletes surveyed in the LSU study and 46.1% of the Purdue athletes. CONCLUSION: The LSU study participants were older than the Purdue study participants. The triathletes from the LSU study report a longer competitive season when compared with the Purdue study. LSU study participants consumed fewer carbohydrates than the Purdue study participants and most triathletes from both studies suffered injuries at the knee.