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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Calcium Intake and the Incidence of Stress Fractures

Unknown Date (has links)
Purpose: The purpose of this study was to compare female runners with a history of stress fractures to matched runners who have no history of stress fractures to determine if differences existed in adolescent dairy intake, current dietary calcium intake, total energy, bone mineral density, and menstrual irregularities. Methods: 27 female runners (aged 18-40) who had at least one stress fracture that had been diagnosed by a doctor were matched to a control sample of 32 female runners who were similar in age, weight, and fat free mass (FFM). Subjects visited the lab in the late follicular phase of their menstrual cycle and consented to a fasting blood draw for assessment of serum estradiol, serum intact parathyroid hormone (iPTH), and serum 25-hydroxyvitamin D (25-(OH)D). Bone measurements were performed by dual-energy x-ray absorptionmetry (DXA). Subjects answered a questionnaire on stress fracture history, training, menstrual status, and lifetime dairy intake, and they also completed a 3-day food record. Results: Subjects did not differ in age, weight, height, FFM, body mass index, or training volume. Menstrual history and current menstrual characteristics were not significantly different between groups, nor were bone measurements at any sites. A greater number of stress fracture subjects were using calcium and/or vitamin D supplements compared to control subjects (p<0.05), and there was a trend for greater dietary calcium intake in control subjects (p=0.077). Previous and current servings of dairy intake did not differ between groups. However, in multiple linear regression, weekly servings of milk during middle school were a significant predictor (p<0.05) of BMD in the total femur, femoral neck, Ward's triangle, and femoral shaft. Number of menstrual cycles in the previous year was a significant positive predictor of femoral neck BMD (p<0.05). Caffeine intake was significantly negatively correlated with BMD of the total femur, femoral neck, trochanter, and femoral shaft. Some training variables were significantly negatively associated with bone, including running pace and total femur, days run per week and 33% radius, and also hours spent exercising per week were negatively correlated with total body BMD, total body BMC, and lumbar spine BMD. Logistic regression was used to identify risk factors for stress fractures, from which two models were created. The first model included the number of years subjects had been running, regular or irregular menstrual history, total body BMD, current dietary calcium, serum 25-(OH)D, and body mass index. The second model included the percent of time subjects trained on hard ground, current dietary calcium, regular or irregular menstrual history, total body BMD, serum 25-(OH)D, and body mass index . Conclusions: Although no significant differences in BMD of various skeletal sites emerged between female runners with and without stress fractures, higher dairy intake during adolescent years, especially middle school milk servings, was highly positively correlated with BMD. Additionally, caffeine intake and training variables were negatively associated with BMD. These results show that adolescent dairy intake contributes to accumulation of bone mass, although improved BMD alone may not be protective against the development of stress fractures later in life. Combined risk factors for stress fractures that emerged in logistic regression included longer running history, training predominantly on a hard surface, irregular menstrual history, lower dietary calcium intake, reduced serum 25-(OH)D, and lower total body BMD. / A Dissertation submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester, 2011. / March 29, 2011. / Stress Fracture, Bone Mineral Density, Athlete, Dairy Intake, Calcium, Vitamin D / Includes bibliographical references. / Emily Haymes, Professor Directing Dissertation; Penny J. Gilmer, University Representative; Jasminka Z. Ilich-Ernst, Committee Member.
32

Physical Performance during 6- and 12-Month Weight Loss in Postmenopausal Women: Relationship with Body Composition and Bone Mineral Density

Unknown Date (has links)
The overall purpose of this study is to investigate the physical performance of early postmenopausal Caucasian women during a 12-month weight reduction program. Additionally, the relationships between body composition (bone, fat and lean mass) and physical performance during that period is explored. A total of 97 participants aged 56.0(±4.3) years old with an average BMI of 30.3(±3.8) kg/m2 were included in this study. Of those, 66 (68 %) and 55 (57 %) participants completed the 6-month and 12-month interventions, respectively. The participants followed prescribed energy-restricted meal plans and were divided into three groups based on calcium and vitamin D intake: hypocaloric diet with calcium+vitamin D supplements (1260 mg/day+800 IU/day), hypocaloric diet with placebo or hypocaloric diet with 5-6 servings of low-fat dairy products. Physical performance measures including handgrip strength, 8-meter walking speed, one leg stance (OLS), timed 8-foot get-up and go test (TGUG) and chair sit-to-stand test (STS) and iDXA scan for body composition and bone mineral density (BMD) were performed at baseline, month 6 and month 12. Fasting blood were drawn to analyze the concentration of serum 25 hydroxyvitamin D (25OHD) by using ELISA. At baseline, a higher percentage of body fat was correlated with poorer physical performance on non-dominant OLS, TGUG, walking speed and STS. Multiple regression analyses controlling for age, weight, height, calcium intake, serum 25OHD, physical activity and smoking status revealed that having more leg fat (%) was related to poorer performance on OLS, TGUG, walking speed and STS indicating this relationship was site specific. In addition, handgrip strength was positively related to total lean mass. Only forearm BMD (radius 33%) was positively correlated with handgrip strength among various skeletal sites. During the 12-month intervention, participants decreased in weight from 81.4±12.1 kg (BMI of 30.2±3.7 kg/m2) to 78.4±13.4 kg (BMI of 29.1±4.3 kg/m2, p<0.001). Among physical performance measures, walking speed and chair STS were significantly improved. The results of linear mixed models showed that the decrease in weight and percentage of fat were related to the improvement in all physical performance measures over time. The change in the amount of lean mass resulted in a positive relationship with the change in the handgrip strength, OLS, walking speed and STS over time. However, no significant relationship was observed between BMD and physical performance measures. Overall, the percentage of fat and its change with weight loss were the most significant predictors of physical performance and its change in overweight/obese postmenopausal women. Even the modest weight loss resulted in improvement of some of the physical performance measures in this cohort of overweight/obese early postmenopausal women. / A Dissertation submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester, 2011. / March 30, 2011. / postmenopausal women, body composition, physical performance, Weight loss / Includes bibliographical references. / Jasminka Ilich-Ernst, Professor Directing Dissertation; Gareth R. Dutton, University Representative; Lynn B. Panton, Committee Member; Maria Spicer, Committee Member.
33

Effects of Beta-Hydroxy-Beta-Methylbutyrate (HMB) on Body Composition, Functionality, MR-Determined Myofiber Dimensions, and Transcript Factors Inovolved in Myofiber Growth in Young and Old Fisher 344 Rats

Unknown Date (has links)
'Sarcopenic obesity,' a recent medical term, refers to a new trend in aged individuals who simultaneously demonstrate reductions and increases in lean mass and fat mass, respectively. As the elderly population increases, the economic burden of sarcopenia also tremendously increases. Recent evidence reveals that HMB directly increases fat oxidation and regulates myoblast differentiation and survival in cell culture, supporting a possible role in attenuating sarcopenic obesity. However, the efficacy of HMB on myogenic capacity and myofiber dimensions has not been investigated. Therefore, the overarching aim of the present study was to determine the effects of 16 wks of HMB administration in young and old rats on age-related changes in body composition, functionality and myofiber dimensions. We also sought to investigate the possible cellular and molecular mechanisms, which mediated these effects. Twelve young (44 wks), 6 middle aged (60 wks), 10 old (86 wks), and 5 very old (102 wks) male Fisher 344 rats were studied. Their body compositions (dual X-ray absorptiometry, DXA), grip strength and sensory motor function (incline plane) were assessed pre- and post-intervention. After DXA, 6 young, 6 middle aged, 5 old and very old rats were sacrificed for baseline muscles, and remaining young (44 wks) and old (86 wks) rats were given 1% HMB (0.46 g/kg/d) feed for 16 wks and then sacrificed for pre- and post-HMB molecular analysis and for diffusion tensor imaging (DTI) of the soleus and gastrocnemius muscles. Transcript factors involved in muscle cell regeneration and growth: myogenin, myogenic differentiation factor (MyoD), and insulin-like growth factor-IEa (IGF-IEa), mechano growth factor (MGF), myostatin, eukaryotic initiation factor 4E binding protein 1 (4EBP1), and atrogin-1 were also assessed with RT-PCR. There was a group effect for total body mass (TBM) increasing (+23%) in the control, but not in the HMB group from 44-60 wks, while it maintained in the control, and declined (-20%) in the HMB group from 86-102 wks. Fat mass (g) increased in the middle aged control (+49%) but not in the HMB group. Fat mass declined (-56%) in the old HMB group but not in the control group. There were overall declines of 25% in absolute grip strength from 44 to 102 wks of age. However, when normalized to TBM, there was a significant group x time effect (p<0.05) in which strength declined in the control group, but was maintained in the HMB group from 44-60 wks. Moreover, HMB improved strength normalized to TBM (+23%) (p<0.05) from 86-102 wks, with no change in the control group. There was a main time effect for sensory motor function, declining 14% (p<0.05) from 44 to 102 wks of age. However, the HMB group demonstrated an 11% increase (p<0.01) from 44-60 wks. There were declines in gastrocnemius, plantaris, and soleus weights normalized to TBM from 60-102 wks. While HMB had no effects on the gastrocnemius, there were decreases in control planaris (-21%) and soleus (-15%) muscles, which maintained and increased (+12%), respectively, in the HMB group from 44-60 wks. There was a significant decline in DTI-determined myofiber dimensions in the gastrocnemius and soleus from 44 to 102 wks as indicated by declines in eigenvalues 2 and 3 (representative of the cross sectional area) in the 102-wk control, but not 102-wk HMB condition. There were significant group effects for both the soleus (p<0.05) and gastrocnemius muscles (p<0.05) for expression of atrogin-1 mRNA which was greater in the 102-wk control group than all other groups in both the soleus and gastrocnemius. However, the rise was blunted in the soleus in the 102-wk HMB condition. There was a main group effect in the soleus for myogenin (p<0.05) which while approaching significance in the 102-wk control group (p=0.056) only significantly increased in the 102-wk HMB group relative to the 44-wk group (p<0.05). While no other main effects were found in any genes analyzed, post hoc analysis revealed that myostatin was lower in the gastrocnemius, and IGF-IEa was greater in the soleus in the middle aged HMB group than the control group. Our findings suggest HMB may produce a leaner phenotype in middle aged and older individuals, and may blunt the age-related loss of myofiber dimensions in lower limb muscles. These effects on myofiber dimensions may be mediated by prevention of protein breakdown (atrogin-1) and improvement of myogenic capacity; however, the mechanisms underlying HMB's effects on fat metabolism remain to be elucidated. / A Dissertation submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester, 2010. / March 29, 2010. / Skeletal Muscle, HMB, Beta-Hydroxy-Beta-Methyl-Butyrate, Sarcopenia / Includes bibliographical references. / Jeong-Su Kim, Professor Directing Dissertation; Samuel Grant, University Representative; Lynn B. Panton, Committee Member.
34

Does Baseline HDL-C Influence the Dose and Response Relationship Between Acute Exercise and Post-Exercise HDL-C Improvement?

Unknown Date (has links)
Does Baseline HDL-C Influence the Dose and Response Relationship Between Acute Exercise and Post-exercise HDL-C Improvement? Purpose: The purpose of this study was to determine if high density lipoprotein cholesterol (HDL-C) status (low vs. normal) affects the magnitude of post-exercise HDL-C changes over a 24 hour period and whether different caloric expenditures (300, 500 and 700 kcals) augment this relationship. Methods: Two groups of healthy untrained male volunteers participated in this study. Subjects were assigned to one of two groups based upon their resting HDL-C level. The LOW HDL-C group consisted of 13 subjects with clinically low HDL-C (< 40mg/dl) and the NORMAL HDL-C group consisted of 14 subjects with normal HDL-C (≥ 45mg/dl). Age, diet, VO2max and anthropometric data were collected prior to initiation of the experimental protocol and were similar for both groups. The characteristics of the LOW group were 21.9 ± 2.0 yrs of age, 1.8 ± 0.1 m tall, weighed 80.9 ± 7.9 kg, and had a BMI of 25.2 ± 2.2 kg/m2, a VO2max of 45.8 ± 5.1 ml/kg/min and a resting HDL-C of 35.7 ± 2.7 mg/dl. Characteristics of the NORMAL group were 23.4 ± 7.1yrs of age, 1.8 ± 0.1 m tall, weighed 78.6 ± 7.6 kg, and had a BMI of 24.3 ± 2.5 kg/m2, a VO2max of 47.5 ± 4.8 ml/kg/min and a resting HDL-C of 53.9 ± 5.8 mg/dl. Subjects randomly completed three nonconsecutive exercise trials (300, 500, and 700 kcals) on a treadmill at 65% of VO2max. Blood samples were collected pre-exercise (PRE), immediately post-exercise (IP), and 24 hours post-exercise (+24). Each sample was analyzed for HDL-C and its subfractions (HDL2-C and HDL3-C) and was corrected for plasma volume shifts. Results: There was no significant main effect of group or condition (kcal expenditure) and no interactions among variables. HDL3-C increased significantly IP regardless of group or caloric expenditure, but was not different from PRE at +24. HDL-C increased (5.6%) significantly IP regardless of group when the 500 and 700 kcal trials were combined, again the effect was transient. Individually, no caloric expenditure produced HDL-C or subfraction changes that were significantly different from one another. Conclusions: Baseline HDL-C status had no significant effect on the magnitude of post-exercise HDLC alterations. Furthermore, post-exercise improvements of HDL-C in untrained men occur via increases in HDL3-C and primarily at caloric expenditures above 300 kcal / A Thesis submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2008. / October 7, 2008. / Blood Lipids, High Density Lipoprotein, Acute Exercise, Cholesterol / Includes bibliographical references. / Robert J. Moffatt, Professor Directing Thesis; Lynn B. Panton, Committee Member; Laurie M. Grubbs, Committee Member.
35

The Effects of Creatine Supplementation on Muscle Performance during the Transition from an Omnivorous Diet to a Lacto-Ovo Vegetarian Diet

Unknown Date (has links)
Converting from an omnivorous (OMNI) diet to a lacto-ovo-vegetarian (LOV) diet has been associated with a decrease in muscle creatine content as a result of the elimination of exogenous creatine intake. Muscle creatine and phosphocreatine are vital in sustaining intense and rapid muscle contractions during exercise. It is unknown if the transition to LOV diet leads to negative impacts on muscle performance due to the reduction of muscle creatine content. PURPOSE: To investigate the effects of creatine supplementation during a 21-day LOV intervention on muscle performance in young males. METHODS: Twenty-eight males (22.2 ± 2.5 yrs old) switched from an OMNI to a LOV diet for 21 days. Participants were assigned into one of two groups: Placebo (Pl; n=15) or Creatine (Cr, 2g; n=13) for 21 days. Muscle strength was evaluated for the upper body by performing 1-repetition maximum (1-RM) tests for the chest press (Smith Machine) and for the lower body by performing maximal voluntary contraction (MVC) of the quadriceps (QUAD) (BiodexTM) before initiation of LOV diet and 21 days after initiation of LOV diet. Muscle endurance for the QUAD was evaluated with two consecutive bouts (bouts 1 and 2) of a fatigue index (FI) test with one minute rest (BiodexTM) at the same time points. Dual-energy-X-ray absorptiometry (DXA) was used to measure body composition at the same time points. Blood samples were collected at same time points. Dietary records were obtained for both OMNI and LOVdiets. RESULTS: There was a group x time interaction (p< 0.05) in FI bout 2 for peak torque, indicating that the QUAD strength for Cr group was changed from 111.62 ± 19.53 (pre) to 121.69 ± 21.5 Newton meters (Nm, post) while that of the Pl group was changed from 138.2 ± 33.08 (pre) to 130.73 ± 32.05 Nm (post) after 21-day LOV intervention. Interestingly, there was a group x time interaction (p=0.05) in FI for percent torque decline during bout 2, indicating that the Cr group changed from -60.75 ± 2.13 (pre) to -61.99 ± 2.53% (post) while Pl group changed from -64.3 ± 2.83 (pre) to -58.64 ± 3.68% (post) after 21-day LOV intervention. There was a group x time interaction (p<0.05) in isometric knee extensions for peak force, indicating that the QUAD strength for Cr group was changed from 204.08 ± 47.05 (pre), to 187.0 ± 43.57 (mid), to 182.0 ± 50.37 Newtons (N,post) while that of the Pl group was changed from 204.87 ± 50.74 (pre), to 211.47 ± 45.36 (mid), to 211.0 ± 53.37 N (post). There was no significant change in body weight, lean body mass, fat mass, total cholesterol, HDL cholesterol, MVC isokinetic extensions at 60, 180, and 300 degrees/second in QUAD, or 1-RM chest press. There was a time effect (p<0.05) indicating a significant decline in protein intake for both groups. CONCLUSIONS: Our findings suggest that 21 days of LOV diet in young males who were previously omnivorous did not have any negative impacts on muscle performance. Daily creatine supplementation (2g/d) during 21-day LOV diet intervention appears to maintain muscle strength during the second bout of consecutive fatigability tests. / A Thesis Submitted to the Department of Nutrition, Food, and Exercise Sciences in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Spring Semester, 2010. / March 26, 2010. / Ergogenic, Ergolytic, Vegetarian Athletes, Sports Nutrition, Creatine Concentration / Includes bibliographical references. / Jeong-Su Kim, Professor Directing Thesis; Emily M. Haymes, Committee Member; Robert C. Eklund, Committee Member; Maria T. Spicer, Committee Member.
36

Effect of Carbohydrate-Protein Supplement Timing on Exerciseinduced Muscle Damage

Unknown Date (has links)
The purpose of this study was to examine if the timing of a carbohydrate/protein supplement would have an effect on post resistance exercise muscle damage, function and soreness. Methods: Twenty one untrained male subjects were given a supplement before or after a bout of resistance exercise. Subjects were randomly assigned to three groups. The pre exercise group (Pre, n=7) received a carbohydrate/protein drink immediately before the exercise bout and a placebo drink immediately after. The post exercise group (Post, n=7) received a placebo drink immediately before the exercise bout and a carbohydrate/protein drink after. The control group (Con, n=7) received a placebo drink before and after the bout of exercise. Subjects performed 50 eccentric quadriceps contractions on an isokinetic dynamometer. Tests for serum creatine kinase (CK), maximal voluntary contraction (MVC) and muscle soreness scores were recorded before the exercise bout then again at six, 24, 48, 72, and 96 hours post exercise. Repeated measures ANOVA (3 x 6 group x time) were used to analyze dependent measures. Significance was accepted at P≤0.05. Results: There were no group by time interactions for any of the measured parameters; however, there were time main effects. Serum CK increased for all groups (P<0.01) when compared to pre exercise values (103±45U/L) reaching its peak at 72 (1156±1990U/L) and 96 hours (1047±1438U/L) post exercise. Maximal voluntary contraction (MVC) was significantly reduced (P<0.01) on average for all groups by 29.5±12% at six hours then dropped to 31.3±15% at 24 hours before gradually returning to pre exercise values. Muscle soreness scores were also significantly increased (P<0.01) from pre-exercise values peaking at 48 hours post exercise. Conclusion: These findings suggest that the eccentric resistance exercise protocol caused significant muscle damage, soreness and loss of strength in all groups. However, the timing or ingestion of the carbohydrate/protein supplement had no effect on those variables. / A Thesis Submitted to the Department of Nutrition, Food, and Exercise Sciences in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Summer Semester, 2005. / July 8, 2005. / Resistance Exercise, Muscle Damage, Creatine Kinase / Includes bibliographical references. / Lynn Panton, Professor Directing Thesis; Tim Moerland, Outside Committee Member; Emily Haymes, Committee Member.
37

The Effects of Three Pre-Exercise Meals on Long and Short-Term Submaximal Cycling Endurance Exercise

Unknown Date (has links)
This study examined the effect of three pre-exercise meals on various blood and cardiorespiratory variables during long-term and short-term submaximal endurance cycling. Eighteen endurance trained males between the ages of 18 and 35 years of age participated in this study examining the effects of a 200 isocaloric meal (in 300 mL) of glucose, whole milk, and an artificially flavored placebo following an overnight fast and a two-day diet high (>60%) in complex carbohydrates on three separate rides at 55% of maximal oxygen consumption for 120 minutes, followed by a 30 minute rest, and a short high intensity ride to exhaustion at 80% maximal oxygen consumption. Subjects were healthy and each paid $100 for their participation. Variables investigated were glucose, glycerol, free fatty acids, lactate, RER, HR, RPE, and time to exhaustion. Blood and cardiorespiratory variables were analyzed using a Repeated Measures ANOVA. Significant differences (p60%) in complex carbohydrates on three separate rides at 55% of maximal oxygen consumption for 120 minutes, followed by a 30 minute rest, and a short high intensity ride to exhaustion at 80% maximal oxygen consumption. Subjects were healthy and each paid $100 for their participation. Variables investigated were glucose, glycerol, free fatty acids, lactate, RER, HR, RPE, and time to exhaustion. Blood and cardiorespiratory variables were analyzed using a Repeated Measures ANOVA. Significant differences (p<0.05) were tested with a Bonferroni post hoc test. Only the means of the free fatty acids were significantly different between the rides (p<.007) with milk and glucola significantly blunting the rise in free fatty acids with exercise. However, all the variables changed over time. On the short ride there were no significant differences between any of the variables. While the differences were not significant, time to exhaustion for the carbohydrate meal was 18% longer than the whole milk meal and 20% longer than the placebo suggesting that a higher kilocaloric meal might have made a significant difference. These results demonstrate that, following an overnight fast, a 200 kilocaloric meal prior to endurance exercise will not make a difference in time to exhaustion whether it is a carbohydrate load or a mixed meal like whole milk. Additionally, a mixed meal of carbohydrate and protein will blunt the free fatty acid response during exercise similar to that of a carbohydrate only meal. / A Thesis Submitted to the Department of Nutrition, Food, and Exercise Sciences in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Spring Semester, 2008. / November 3, 2007. / Placebo, Whole Milk, Endurance Exercise, Bonferroni / Includes bibliographical references. / Emily Haymes, Professor Directing Thesis; Akihito Kamata, Outside Committee Member; Robert Moffatt, Committee Member; Jodee Dorsey, Committee Member.
38

Factors Affecting the Ability to Sustain Maximal Work

Unknown Date (has links)
Purpose: The purpose of this investigation was to examine the ability to sustain a maximal running effort. Furthermore, the effects of aerobic fitness level, gender, anaerobic capacity, efficiency of energy production and utilization, and lactate threshold on maximal performance were examined. Methods: Maximal oxygen consumption (VO2max), ventilatory threshold (VT) and anaerobic capacity (AC) were determined for 22 subjects. Subjects then performed a treadmill test to exhaustion to determine the time spent at VO2max, time spent at the velocity (run speed) associated with 100% VO2max (vVO2max), and the time it took to reach VO2max at vVO2max. Statistical analysis included one-way ANOVA by gender, VO2max, gender/VO2max and VO2max/AC. Tukey's post-hoc tests were done to determine location of significance. Pearson product-moment correlations were performed between physiologic variables [VO2max, AC, VT, gross efficiency (GE) and net efficiency (NE)] and maximal run performance (time spent at VO2max and vVO2max, and time to reach VO2max). Results: Average time spent at VO2max was 0.79±0.13 minutes and time spent at vVO2max was 2.36±0.20 minutes. No differences in maximal run performance were observed between high fit (HF) and low fit (LF) groups; however, females spent significantly longer time at VO2max and vVO2max compared with males (p Conclusions: VO2max does not appear to be directly related with the ability to sustain a maximal run performance, while females spent a longer time at VO2max and vVO2max than males. GE and NE showed a moderately positive relationship with time at vVO2max and time to reach VO2max. / A Thesis Submitted to the Department of Nutrition, Food & Exercise Sciences in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Summer Semester, 2010. / June 30, 2010. / Gross and Net Efficiency, Anaerobic Capacity, Ventilatory Threshold, Time to Reach VO2max, vVO2max, VO2max / Includes bibliographical references. / Robert J. Moffatt, Professor Directing Thesis; Lynn B. Panton, Committee Member; Thomas Ratliffe, Committee Member.
39

Dual Task Performance and Postural Recovery

Unknown Date (has links)
The purpose of this project was to examine limitations of human motor control during postural recovery. A dual task paradigm, the Psychological Refractory Period (PRP), was used to overload the attentional resources of a group of young (20-35 yrs.) and older (70-85 yrs.) adults. Specifically, the intention was to identify age-related differences associated with the selection of an appropriate rapid, discrete muscular response concurrent to the execution of an automatic (non-attention demanding) postural response. Subjects were required to respond as quickly and accurately to two closely presented stimuli; a precision grip force task (HHFT) and toes-up perturbation, respectively. Reaction time and the waveform integrals for each task were analyzed using a 3 (SOA) x 2 (conditions) x 2 (age-groups) mixed model repeated measures ANOVA. Participants apparently restructured the task requirements so posture could be equilibrated, but at a cost of reduced speed and accuracy of the primary task. Also, MLR and LLR amplitudes were greater as the SOA shortened. Data suggest that young and elderly grouped the griping response with the APR. The primary stimulus appeared to be a primer to prepare both responses for the platform rotation trigger. It was concluded that postural recovery is attentionally demanding. Moreover, this study reinforces the notion that postural recovery involves feedforward as well as feedback control mechanisms. Effects of the interference task on postural mechanisms may depend upon the underlying mechanisms of motor control rather than sensory deprivation. / A Dissertation Submitted to the Department of Nutrition, Food and Exercise Science in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Summer Semester, 2003. / July 8, 2003. / Limitations Of Human Motor Control During Postural / Includes bibliographical references. / Tonya Toole, Professor Directing Dissertation; John E. Bertram, Committee Member; George Weaver, Outside Committee Member.
40

A Comparison of the Effects of Post Exercise Basal Metabolic Rate Among Continuous Aerobic, Intermittent Aerobic, and Resistance Exercise: Implications for Weight Control

Unknown Date (has links)
Purpose: To compare the effects of three bouts of exercise, resistance (RE), continuous aerobic (CA), and intermittent aerobic (IA), matched for energy expenditure (kcal) and rate of oxygen consumption (VO2), on 12h post exercise metabolic rate and basal metabolic rate (BMR). Ten healthy men (age: 22 ± 2 yrs, height: 173.8 ± 11.6 cm, weight: 77.1 ± 16.4 kg, VO2max: 34.5 ± 6.1 ml/kg/min) were recruited to participate in this study. 12h post exercise and BMR were measured on four sessions over a four week period: control, RE, CA, and IA. For each session, subjects performed exercise at 9.00 am and returned to the laboratory at 9.00 pm to have their 12 h post exercise metabolic rate measured and to stay overnight in the laboratory, to have their BMR measured the following morning. For RE session, subjects performed one circuit of five exercises vertical butterflys, squats, toe raises, lateral pulldowns, and triceps press downs at approximatedly 50-60% of their maximal lifts. Each set was performed until failure, and followed by 60s of rest. The circuit was repeated for a total of 45 min of exercise. VO2 was measured continuously and used for calculating the total amount of energy expenditure (216 ± 19 kcal) and average rate of VO2 (12.5 ± 1.8 ml/kg/min). For CA, subjects cycled at a work load that produced the same average rate of VO2 at each subject's average rate of VO2 during the RE. For IA, subjects cycled at high intensity interval between 90%-100% of VO2max for 30 seconds and a low intensity interval at 20-30% of VO2max. For the low intensity interval, subjects cycled until the average rate of VO2 in that interval matched the average rate of VO2 during the RE. For both CA and IA, subjects cycled until spending the same amount of kcal measured during RE (exercise duration; CA: 43.2 ± 2.3; IA: 43.5 ± 1.8min). For 12h post exercise metabolic rate, RE caused greater increases in metabolic rate compared to the control (14.6%), CA (9.3%) and IA (4.4%). IA also had significantly higher metabolic rate compared to the control (9.8%) and CA (4.7%). BMR was significantly higher after RE compared to the control (15.6%), CA (12.1%), and IA (12.1%). These results suggest that RE has greater effects on BMR compared to CA and IA, indicating the importance of further research to examine a possible role for RE in controlling body weight. / A Dissertation Submitted to the Department of Food, Nutrition, and Exercise Sciences in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Spring Semester, 2006. / March 27, 2006. / Resistace, BMR, Exercise, Weight / Includes bibliographical references. / Lynn Panton, Professor Directing Dissertation; Penny J. Gilmer, Outside Committee Member; Robert Moffatt, Committee Member.

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