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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.
1131

Familial history of hypertension : hemodynamic responses to exercise in children

Kelsey, Kira Q. January 1996 (has links)
Hypertension afflicts one in four American adults and is a major risk factor for cardiovascular disease. Studies have shown that a family history of hypertension is an important predictor of future hypertension. Two hemodynamic factors control blood pressure (BP); cardiac output (CO) and total peripheral resistance (TPR). Although children of hypertensive parents may exhibit normal levels of these hemodynamic variables at rest, the response of these variables during exercise stress may differ. Therefore, the present study was designed to investigate whether children with a positive family history of hypertension exhibit an exaggerated BP response due to either an increased CO or an attenuated decrease in TPR during dynamic submaximal exercise compared to children of normotensive parents. Eleven children 12.2 ± 1.8 yr (M ± SE) of normotensive parents and 11 children 12.0 ± 2.4 yr of at least one hypertensive parent completed an orientation session, graded maximal cycle ergometer test, and a submaximal exercise bout consisting of 6 minutes of steady state cycling at 50 and 80% of maximal heart rate reserve. Blood pressure, CO and TPR were measured during the last 3 minutes of each submaximal exercise stage. An independent t-test was used to determine differences in the resting measures. The changes in TPR, BP and CO from rest through 80% intensity stage were examined using a twoway (group x intensity) ANOVA. The groups were evenly matched for age, weight, height, and body fatness. The children with a positive family history of hypertension had significantly higher resting systolic BP, diastolic BP (DBP), and mean arterial pressure (MAP) (p<0.05) compared to those children with a negative family history. Although there were no significant interactions among any of the variables studied, there was a tendency for TPR to be higher (p>0.05) at rest and throughout exercise in the positive history group. MAP and DBP were significantly higher in the positive family history group at rest and remained higher throughout exercise. In conclusion children of hypertensive parents exhibit a modest but significantly higher MAP and DBP at rest and during submaximal exercise. This subtle difference in BP control reflects an early trend toward increased TPR. / School of Physical Education
1132

Skeletal muscle function and myosin heavy chain expression with Multiple Sclerosis

Carroll, Chad C. January 2001 (has links)
The purpose of this investigation was to examine the effects of Multiple Sclerosis (MS) on the structural and functional characteristics of skeletal muscle. More specifically, we analyzed the myosin heavy chain (MHC) and fiber type distribution of the vastus lateralis, measured single fiber cross sectional area (CSA), and determined the isokinetic and isotonic strength of the knee extensor muscles. Six sedentary subjects with MS (age: 44 ± 2 yrs) and six sedentary gender-matched controls (age: 46 ± 4) were evaluated. EachMS subject was rated on the Kurtzke's Expanded Disability Status Scale (EDSS) and performed an 8-meter walk test to determine gait speed. Furthermore, the spasticity of the knee extensors was evaluated in each MS subject and weekly energy expenditure was estimated using the Yale Physical Activity Survey. Concentric and eccentric isokinetic strength of the right knee extensors (left in one MS subject) was determined at 60 and 180°/sec and a bilateral isotonic one-repetition maximum (1-RM) was evaluated in eachsubject. Muscle biopsies were taken from the right vastus lateralis (left in one MS subject) and individual fibers were dissected from these samples. Fibers were submitted to SDSPAGE with silver staining to determine MHC expression. Densitometry was performed on MHC hybrid fibers to determine the degree of co-expression. An additional section ofthe biopsy was stained for mATPase activity and further analyzed for single fiber CSA and fiber type. The mean EDSS score for the MS subjects was 5.4 ± 0.6 (range 3.5-6.5) and MS patients were slower than controls (p < 0.05) on the walk-test. AshworthSpasticity Scores ranged from 0 - 2. No differences were noted in weekly energy expenditure. The controls were 45 and 56% stronger than the MS group at isokinetic concentric velocities of 60 and 180°/sec (p < 0.05), respectively. The isotonic 1-RM andthe eccentric isokinetic contractions were not different between the two groups. There were no differences noted in any of the MHC isoforms or percentage of hybrid fibers. Furthermore, mATPase fiber type distribution and single fiber CSA were not different between the groups. There was a greater proportion of MHC IIx dominant MHC IIa/IIx fibers in the MS groups (p < 0.05). Multiple Sclerosis appears to result in large strengthdeficits, when compared to healthy individuals. Based on our findings, these strength differences cannot be explained by alterations in MHC/fiber type expression or decreases in fiber CSA. / School of Physical Education
1133

Endurance training adaptations in adolescent female cross-country runners

Woodruff, Megan E. January 2005 (has links)
This study evaluated the training adaptations in female adolescent cross-country runners over two training seasons. Although the effects of endurance training in this population are understood, the specific adaptations resulting from pre-season and in-season training are not clear. The physiological changes occurring over these two training seasons in 10 female runners (15.7 ± 0.8 yrs, 165.6 ± 5.6 cm, 53.8 ± 6.1 kg) were assessed. Maximal exercise responses were measured during a continuous graded exercise test and submaximal exercise responses were quantified at 7 and 8 mph. Isokinetic muscle strength was assessed at four movement speeds (60-240°/sec) and muscle power was calculated using vertical jump height. Body composition also was assessed. HR at maximal and submaximal exercise declined during pre-season training and then increased during in-season training. Blood lactate [BLa] measurements at 7 and 8 mph decreased following summer training. Whole body bone mineral content (BMC) and bone mineral density, and femoral head BMC increased. In conclusion, it appears that high volume, low intensity training lowers [BLa] with no corresponding change in oxygen utilization in highly trained female adolescents. Running also appears to have a positive impact on bone mass in female adolescents. / School of Physical Education, Sport, and Exercise Science
1134

The muscle specific protein synthesis response to acute running exercise utilizing multiple stable isotope tracers

Crane, Justin D. January 2008 (has links)
The purpose of this study was to compare the anabolic response to acute running exercise in two different leg muscles in endurance-trained men using two different stable isotope tracers. 6 male subjects (26±2 yr; V02max 63±2 ml•kg-' •min-') performed a 45 min treadmill run at 77±1 % intensity. Infusions of d3-leucine and d5-phenylalanine were used to measure mixed muscle FSR at rest and 24 hr post-exercise. An additional infusion of 10% amino acid solution was added to the post-exercise infusion to maximize the muscle anabolic response. Muscle biopsies were obtained from the vastus lateralis (VL) and soleus (SOL) at 2 and 6 hr of the infusion for the measurement of isotope incorporation. Additional muscle biopsies were obtained prior to and 4 hr post-exercise for determination of muscle glycogen use. At rest FSR was similar between the VL and SOL using either tracer (p>0.05). At 24 hr post-exercise FSR was elevated in both muscles, independent of the tracer used (p<0.05). Muscle glycogen was decreased to the same extent in both muscles by -31% at 4 hr post-exercise (p<0.05). These data suggest that the VL and SOL muscles are both stimulated similarly during 45 min of level grade running. Additionally, both muscles respond similarly 24 hr post-exercise, independent of the tracer used for the determination of protein synthesis. / School of Physical Education, Sport, and Exercise Science
1135

Subtyping children's learning disabilities with neuropsychological, intellectual and achievement measures

D'Amato, Rik Carl January 1987 (has links)
The present study was an effort to empirically subtype children's learning disabilities. A review of the literature was presented with a focus on current and historical subtypingattempts. A cluster analysis was performed on 1144 school-age learning disabled children who had completed extensive neuropsychologica1, intellectual, and achievement measures. Four interpretable clusters emerged which were seen as (1) Verbal-Sequential-Arithmetic Deficits, (2) Motor Speed and Cognitive Flexibility Deficits, (3) Mixed Language/Perceptual Deficits, and a (4) No Deficit Subtype. Not only did these clusters indicate unique profiles for each subtype across the sample, but developmental differences were also apparent between all four clusters. The current investigation suggested the utility of an empirical-neuropsychological approach to subtyping children's learning disabilities, while also portraying the importance of neurodevelopnental considerations of subtypes. Future directions in research were discussed. / Department of Educational Psychology
1136

Influence of gender and muscle origin on skeletal muscle gene expression at rest and following maximal resistance exercise

Louis, Emily S. January 2008 (has links)
The aim of this investigation was to compare the acute anabolic and catabolic responses of male and female vastus lateralis (VL) and soleus (SOL) muscles in response to resistance exercise (RE). Muscle biopsies from the VL of 7 males (26±3 y, 75±8 kg) and 7 females (25±3 y, 59±5 kg) were obtained before, and 2 and 6 h after 4 x 7 supine-squat, and 4 x 14 calf-press exercises at maximal effort using inertial ergometry. The mRNA levels of select myogenic (MyoD, myogenin, MRF4), proteolytic (atrogin-1 , MuRF-1), myostatin, and inflammatory (IL-6, -8, -15) genes were quantified using real-time RT-PCR. Male VL vs SOL: The SOL had higher basal mRNA levels of myogenic, proteolytic, and inflammatory genes. After exercise, the myogenic response was similar between the VL and SOL. Both muscles increased MuRF-1 similarly at 2 h, whereas 6 h post-RE proteolytic gene expression (GE) was suppressed in the VL but not in the SOL. The SOL had a reduction in myostatin GE, and a more robust inflammatory response compared to the VL. These findings indicate a more favorable growth response in the VL. Gender comparisons: VL – Basally, the male VL had higher levels of myogenic, proteolytic, myostatin, and inflammatory mRNA compared to the female VL. After exercise, both genders increased myogenic GE similarly. Both genders increased MuRF-1 initially, with females also increasing atrogin-1 and myostatin post-RE. At 6 h, males decreased proteolytic GE to below basal levels. Females also had a greater inflammatory response than males. These findings indicate a greater growth response to RE in the male VL as compared to the female VL. SOL – After exercise, both genders increased myogenic GE in the SOL, but only males increased MyoD expression. Males increased MuRF-1 mRNA but decreased myostatin GE, while females decreased atrogin-1. The inflammatory response was similar between males and females. Despite the modest differences, the net response of the female and male SOL was similar, and indicated a molecular response slightly favorable for growth. / School of Physical Education, Sport, and Exercise Science
1137

Skeletal muscle morphology and function in former elite distance runners : a 20 year follow-up

Trappe, Scott W. January 1994 (has links)
The purpose of this investigation was to examine the effects of 20 years of distance running training on the morphological and functional characteristics of skeletal muscle. Sixty men (current age = 49.2 ± 2.4 yr.) were first studied between 1966-1974 when they were all highly trained. Based on their training regimens in the interim between testing, subjects were described as highly trained (HI), fitness trained (FIT) or untrained (UT). Gastrocnemius muscle biopsy samples revealed an increase (p<0.05) in the proportion of type I fibers of the FIT (52.9 ± 5.3 vs. 61.9 ± 5.2%) and UT (56.3 ± 2.9 vs. 65.4 ± 3.8%) groups, while the HI group, who was initially characterized by a high percentage (>70%) of type I muscle fibers, was unchanged. Among the elite distance runners who had continued high volume, high intensity running, succinate dehydrogenase (SDH) activity and type I and type II muscle fiber areas were similar between evaluations. In 1993, the HI group had higher (p<0.05) SDH and citrate synthase (CS) activities compared with the FIT and UT groups, whereas phosphorylase activity did not differ. Capillary density and capillary-to-fiber ratio were also greater (p<0.05) in the HI group compared with the other two groups. Isokinetic plantar flexion strength at 60°/s and 180°/s and cross-sectional area (CT scans) of the lower leg (gastrocnemius and soleus) were similar among groups. These data suggest that aging may have a significant effect upon the distribution of muscle fibers and may be dependent upon fiber composition as a young adult. In addition, sustained endurance training appears to maintain the oxidative characteristics of the skeletal muscle, but does not provide an advantage in absolute calf muscle strength compared with individuals who train considerably less or not at all. / School of Physical Education
1138

A minimalistic model of resistance training : effects on skeletal muscle function during unloading

Schulze, Kimberley E. January 1999 (has links)
Since astronaut time and energy are at a premium, effective countermeasures must be designed to maximize benefits while minimizing time/energy cost. Therefore, our intent was to design and evaluate a low volume, high intensity resistance training program (RTP) on the preservation of knee extensor and plantar flexor size, strength and neuromuscular function in response to unloading. A total of 32 subjects participated. Sixteen men underwent 21 days of unilateral lower limb suspension (ULLS) and were assigned to control (no RTP) (ULLS-CON, n=8) or countermeasures (ULLS-CM, n=8). The remaining subjects were ambulatory for 21 days and were assigned to no RTP (n=8) or countermeasures (n=8). Countermeasure subjects performed RTP every third day during the suspension period (total=6). The RTP consisted of 2 maximal isometric contractions (MVC), 1 set of 10 concentric/eccentric isotonic repetitions, and 1 set to exhaustion, at 80% of 1-repetition maximum (1RM). There was no change in muscle function in ambulatory subjects. Whole muscle cross sectional area (CSA) measured by computed tomography (CT) decreased 7% (thigh) and 7.5% (calf) in ULLS-CON (p<0.05), and was unchanged in ULLS-CM. MVC decreased 16.5% in both quadricep and calf muscles in ULLS-CON (p<0.05) and increased 6% in the quadricep of ULLSCM (p<0.05). Maximal concentric (CNC) and eccentric (ECC) isokinetic strength decreased an average of 18% and 17% in the knee extensors and plantar flexors of ULLS-CON, respectively (p<0.05) and was unchanged in ULLS-CM. 1RM decreased 16% in both quadricep and calf of ULLS-CON (p<0.05) and was unchanged in ULLSCM. Knee extensor work capacity, evaluated during 30 maximal CNC contractions (3.14 rad•sec-'), decreased 18% in ULLS-CON (p<0.05). Neural activation of knee extensors and plantar flexors was measured by electromyography (EMG). Submaximal v.lat, v.med, gast and sol EMG increased in ULLS-CON (p<0.05) and was unaltered in ULLSCM. Maximal EMG decreased 20% and 26% in v.1at and v.med, respectively in ULLSCON (p<0.05). ULLS-CM showed a 15% and 28% increase in v.med and gast maximal EMG (p<0.05). These data suggest knee extensor and plantar flexor muscle size, strength and neuromuscular function were preserved during unloading using a low volume, high intensity RTP performed every third day. / School of Physical Education
1139

Emotional cycles maintaining trichotillomania (hair-pulling disorder) across subtypes

Siwiec, Sebastian, University of Lethbridge. Faculty of Education January 2013 (has links)
The emotions associated with initiating, maintaining, and reinforcing hairpulling disorder (trichotillomania) were studied. Studies conducted have only looked at small community or inpatient samples, and little is known about the interplay of hairpulling subtypes and emotions. For this study, 427 participants completed an online questionnaire around their hairpulling subtype, severity, emotions experienced by hairpulling, and comorbid anxiety and depression. Using the Milwaukee Inventory for Subtypes of Trichotillomania-Adult Version (MIST-A; Flessner, Woods, Franklin, Cashin, & Keuthen, 2008), this is the first study to address the regulation of emotions across subtypes. Participants were divided as either high- or low-focused and either high- or low automatic. Significant differences between hairpulling subtypes and hairpulling severity were reported. Subtypes differed in the severity they experienced emotions; individuals with high-focused pulling reported more intense negative emotions, and a greater number of emotions regulated by pulling. Positive emotions⎯happiness, relief, and calm⎯were also found to play a significant role in reinforcing hairpulling. For high-focused subtypes, negative emotions before- and after-pulling were associated with greater severity, indicating that altering negative emotions via pulling plays an important role for high-focused subtypes. High-focused subtypes also reported higher stress, depression and anxiety than either automatic subtypes or the general population, and were found to have anxiety and depression significantly associated with hairpulling severity and experiencing negative emotions that initiated hairpulling. Clinical and treatment implications, study limitations, and areas of future research are discussed / xviii, 227 leaves ; 29 cm
1140

Effect of hand cooling on thermal and psychophysical strain and performance during high intensity intermittent training of elite swimmers

Zochowski, Thomas 25 January 2010 (has links)
The purpose of the present study was to determine the effects of using intermittent hand cooling during high intensity, intermittent training on measures of thermoregulatory, performance and psychophysical variables in elite level swimmers in warm pools (30.50.5°C). Following a standard warm-up, ten male swimmers (20.3±3.2 yrs) were instructed to maintain the fastest average 100m time for an 8x 100m freestyle swimming set separated in a cool pool (CP), warm pool with cooling (WPC), and warm pool with no-cooling (WPNC). Time at 50m and 100m, core temperature (Tc), and heart rate (HR), as well as the rate of perceived exertion (RPE), thermal comfort (ThC) and thermal sensation (ThS) were recorded following each repetition. Participants were cooled during the 90 second rest interval between repetitions using the Rapid Thermal Exchange (RTX) [AVAcore Technologies Inc., Ann Arbor, MI]. There was a significant increase in performance when comparing the second 50m split time (1.16 ± 1.58s ) and 100m time (1.50 ± 1.98s) for the final repetition in the WPC condition compared to the final repetition in the WPNC condition (p<0.05). FIR, ThC and ThS were lower in the CP condition than the WPC and WPNC conditions (p<0.05). There was no significant difference in Tc and RPE between conditions. It was concluded that the results may be due to a placebo effect and at this time there appears no physiological or psychophysical advantage in using the RTX during high intensity, intermittent training of elite swimmers.

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