• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 121
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 521
  • 521
  • 97
  • 78
  • 70
  • 70
  • 57
  • 52
  • 44
  • 44
  • 43
  • 41
  • 38
  • 34
  • 29
  • 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.
401

The Role of Nitric Oxide, Acetylcholine, and Vasoactive Intestinal Peptide on Skin Blood Flow During In-Vivo Electrical Field Stimulation

Thiebaud, Robert S. 02 August 2010 (has links) (PDF)
The purpose of this study was to characterize a novel technique to study neurogenic control of cutaneous vasodilation. We monitored skin blood flow (SkBF) during in-vivo electrical stimulation (e-stim) intended to activate cutaneous nerves and used intradermal microdialysis to deliver receptor antagonists to characterize their contribution to cutaneous vasodilation. We examined the role of acetylcholine receptors (RACh), nitric oxide (NO), and vasoactive intestinal peptide receptors (RVIP) on the cutaneous vasodilation induced by e-stim in the absence of the sympathetic adrenergic nervous system. Six men and three women participated in the study. Three intradermal microdialysis probes were placed in the skin of the dorsal side of their forearm. The adrenergic nervous system was eliminated by delivery of a cocktail of phentolamine (0.01 mg/ml), propranolol (1 mM), and BIBP-3226 (10 µM). At one skin site atropine (0.1 mg/ml) was delivered to block RACh. At a second site we blocked nitric oxide synthase (NOS, 10 mM L-NAME) and RACh. Finally at the third site, we blocked RACh, NOS, and RVIP (0.47 mg/ml VIP10-28). The SkBF response to 1 minute stages of graded increases in frequency (0.2, 1, 2, 4, 8, and 32 Hz) at a current of 1.0 ± 0.1 mA was used to generate a stimulus-response curve before and after drug delivery. At skin site 1 RACh blockade decreased the area under curve (AUC) by 4% from 614 ± 279 to 591 ± 331 (p>0.05). Nitric oxide synthase and RACh blockade reduced the vasodilator response to e-stim by 23% from 1036 ± 457 to 801 ± 448 AUC (p>0.05). Combined NOS, RACh, and RVIP blockade reduced the vasodilator response by 48% from 802 ± 412 to 418 ± 268 AUC (p=0.07). RACh blockade had no effect on the vasodilator response to e-stim. However, in these preliminary studies both NOS and RVIP blockade provided some attenuation of the cutaneous vasodilator response associated with e-stim. Additional studies will focus on these two neurotransmitters as this novel method is refined. Advantages of e-stim include activating the sympathetic nervous system without activating local and humoral factors and studying neurotransmitters in an in-vivo setting during rest, thermal stress, or exercise.
402

Effect of Experimentally-Induced Anterior Knee Pain on Postural Control

Falk, Emily Elizabeth 11 November 2011 (has links) (PDF)
Context: Knee pain is experienced by many people. Because of this, authors have started researching the effects of pain on lower extremity mechanics and also on static and dynamic postural control. However, the effects of pain are difficult to study due to associated confounding variables. Objective: We asked: (1) Will experimentally-induced anterior knee pain alter perceived pain using the visual analogue scale? ; (2) will perceived pain affect postural control as measured by center-of-pressure during static and dynamic movement? Design: Crossover. Setting: Biomechanics laboratory. Participants: Fifteen healthy subjects. Intervention: Each subject participated in single leg quiet stance, landing, and walking trials under three conditions (pain, sham, control), at three different times for each condition (pre-injection, injection, and post-injection). Main Outcome Measures: The dependent variables were measured at pre-injection, injection, and post-injection. Pain was measured using the visual analogue scale across all three times during each condition. Center-of-pressure sway was measured during single leg quiet stance to calculate the average center-of-pressure velocity in the anterior-posterior and medial-lateral directions. The center-of-pressure time to stabilization was measured in anterior-posterior, medial-lateral, and vertical directions, and center-of-pressure trajectory excursion was measured in the medial-lateral direction during walking. Results: Perceived pain was significant (P < 0.05) but did not affect postural control as measured by center-of-pressure medial-lateral and anterior-posterior sway during single leg quiet stance, in time to stabilization during landing, and in medial-lateral excursion during walking. Conclusions: Injection of hypertonic saline resulted in statistically significant perceived pain but did not affect postural control as measured by center-of-pressure medial-lateral and anterior-posterior sway during single leg quiet stance, in time to stabilization during landing, and medial-lateral excursion during walking.
403

The Relationship Between Source of Self-Esteem and Body Composition in College Women

Moncur, Breckann Faun 16 March 2011 (has links) (PDF)
Purpose: The purpose of the study was to determine the relationship between achievement self-esteem, self acceptance self-esteem and body composition in college women. Methods: One-hundred and fifty eight college women were recruited to participate in the study. Participants were healthy, between the age of 18 and 25 yrs, not taking medication that would alter metabolism, and able to participate in physical activity without restriction. As part of the study the participants filled out the Worth Index, which measured level of self-acceptance and achievement self-esteem. The questionnaire included four subscales: basic human worth, performance factor, personal security and appearance. Body composition was assessed using the BOD POD. Results: Participants in the study were 19.9 ± 1.7 yrs, had a BMI of 22.5 ± 3.2 kg/m² and a percent body fat of 26.4 ± 6.4. Source of self-esteem was primarily self-acceptance self-esteem with participants on average scoring 65 ± 11 out of 84 (high moderate) compared to an achievement self-esteem score of 35 ± 10 out of 84 (low moderate). When evaluating the subscales a similar trend appears with the exception of the performance factor, which was more normally distributed. Achievement self-esteem in appearance was positively correlated to percent body fat (p<0.05). Global self-esteem was not related to percent body fat in this population. BMI was negatively related to performance factor and appearance with self-acceptance self-esteem (p<0.05). Global self-esteem was significantly lower for individuals in the highest BMI category. Conclusion: College women who identified less with achievement self-esteem in the subscale of appearance had a lower percent body fat than women who identified more with achievement self-esteem in the subscale for appearance. Also, women who had a higher BMI identified less with self-acceptance self-esteem in the subscales of appearance and performance. Women who had a higher BMI had lower overall self-esteem.
404

A Multiple-Linear Regression Model to Predict Carotid Artery IMT in a Senior Population of Competitors at the Huntsman World Senior Games

Smith, Cheryl Ann 12 March 2012 (has links) (PDF)
Carotid intima-media thickness (cIMT) is a valid measure of cardiovascular disease (CVD). Physical activity appears to improve cIMT, however, research is inconclusive. This study investigated the relationship between physical activity (physical activity rating (PA-R)) and cardiovascular fitness (predicted VO2max , perceived functional ability (PFA)) and cIMT. Data collected from 341 seniors (≥50 years) competing in the Huntsman World Senior Games (HWSG) included blood lipids, inflammatory makers, blood glucose, blood pressure (BP) and anthropometric measurements of obesity and central adiposity. Multiple regression analysis was used to determine correlations of measured variables with cIMT. Two of the fitness related variables, PFA (r ≈ 0.1359; p = 0.012) and predicted VO2max (r ≈ 0.1475; p = 0.007) were significantly correlated to cIMT without controlling for confounding factors, but lost significance when adjustments for other CVD risk factors were included. PAR (r ≈ 0.0869; p = 0.111) was not significantly correlated to cIMT. Regression analysis indicated that the most predictive variables of cIMT we investigate were: age (t = 7.166, p = 0.000), gender (t = 3.310, p = 0.001), BMI (t = 1.892, p = 0.05), SBP (t = 3.952, p = 0.000), total cholesterol (TC) (t = 4.184, p = 0.000) and triglycerides (TRG) (t ≈ 3.466, p = 0.000), our R2 = .299, thus indicating these 6 variables account for about 30% of the variance in cIMT in seniors competing at HWSG. Physical activity and cardiovascular fitness influence other CVD risk factors and consequently may have an indirect impact on cIMT.
405

Dietary Fiber Consumption and Insulin Resistance: The Role of Body Fat and Physical Activity

Breneman, Charity B. 28 November 2011 (has links) (PDF)
Background: This study was conducted to determine the association between fiber intake and insulin resistance in 264 women using a cross-sectional design. Methods: Insulin resistance was indexed using HOMA-IR (fasting insulin (μU/mL)×fasting glucose (mg/dL)/405). HOMA-IR values were log transformed. Fiber and energy consumption were assessed using 7-day weighed food records. Fiber was expressed as grams per 1000 kilocalories. Body fat percentage (BF%) was measured using the BOD POD and physical activity (PA) was ascertained using Actigraph accelerometers worn for 7 consecutive days. Results: (Mean±SD) age: 40.1±3.0 years, glucose: 86.7±5.9 mg/dL; insulin: 7.1±4.3 μU/mL; HOMA-IR: 1.5±1.0; fiber intake (g/1000 kcal), total: 9.3±2.9; soluble: 1.7±0.9; insoluble: 3.8±1.9; physical activity: 2.7044 ±0.7842 million counts; BF%: 31.7±6.9; weight (kg): 66.1±10.1; total caloric intake per day (kcal): 2054.1±320.9; and dietary fat intake (% of total kcal): 30.5±0.5. Women with high total fiber intakes had significantly less insulin resistance than their counterparts (F=4.58, p=0.0332), and women with high soluble fiber intakes had significantly lower levels of insulin resistance than other women (F=7.97, p=0.0051). Participants with high insoluble fiber intakes did not differ from their counterparts (F=0.7, p=0.6875). Adjusting for either PA or BF% weakened the relationships significantly. Controlling for BF% nullified the total fiber-HOMA-IR link (F=1.96, p=0.1631), and attenuated the association between soluble fiber and HOMA-IR by 32% (F = 6.86, p=0.0094). To facilitate interpretation of the results, odds ratios were calculated to determine the association between fiber intake and HOMA-IR with both variables treated as categorical. To create dichotomous variables, fiber intake and HOMA-IR were each divided into two categories using the median (Low and High). In women who had high soluble fiber intake (upper 50%), the odds of having an elevated HOMA-IR level was 0.58 (95% CI: 0.36-0.94) times that of women with low soluble fiber intake (lower 50%). And after controlling for all of the potential confounding factors simultaneously, the odds ratio was 0.52 (95% CI: 0.29-0.93). Conclusion: High fiber intake, particularly soluble fiber, is strongly related to lower levels of insulin resistance in women. Part of this association is a function of differences in PA and BF%.
406

Multifidus Muscle Size and Atrophy Among Dancers With and Without Low Back Pain

Smyres, Alyssa Leann 08 August 2012 (has links) (PDF)
Design: A single-blinded, cross-sectional observational study. Objectives: Examine muscle cross-sectional area and symmetry of the lumbar multifidus muscle in elite ballroom dancers with and without low back pain (LBP). Background: The incidence of LBP among elite ballroom dancers is high and at Brigham Young University is 57%. Previous research has linked lumbar multifidus muscle atrophy to low back pain; however this relationship has not been examined in ballroom dancers. Methods and Measures: Lumbar multifidus cross-sectional area was assessed at rest on the right and left side at levels L1-L5. Thirty-seven subjects (age 24 ± 3.2 years; height, 172.8 ± 11.3 cm; mass, 54.6 ± 4.5 kg) were divided into one of three groups. Participants who reported LBP severe enough to interfere with dance training and daily living were allocated to the LBP group (reported pain at rest, during dance, and following dance) (n=15). Subjects who reported LBP that was not strong enough to interfere with training and daily living were allocated to the minimal pain group (reported pain during dance and following dance) (n= 6). And those who reported no back pain were put into the no pain group (n=16). Results: There were no significant difference in demographics between the groups (P>0.05). There was no significant difference between groups in multifidus cross-sectional area (P = .437). Asymmetry was found in all groups with the left side being larger than the right (P < .002). Conclusion: This study provides new information on lumbar multifidus cross-sectional area in elite ballroom dancers. Future research needs to examine other causes of LBP in elite ballroom dancers in an attempt to decrease LBP in these athletes.
407

A Comparison of Two Tape Techniques on Navicular Drop and Center of Pressure Measurements

Prusak, Krista M. 07 July 2012 (has links) (PDF)
Introduction: Foot over-pronation, attributable to Tibialis Posterior (TP) muscle weakness, is a possible cause of medial tibial stress syndrome (MTSS)3. Taping may provide a viable alternative for a dysfunctional TP and its associated navicular drop (ND). The most commonly used Augmented LowDye (ALD) technique has shown to prevent ND, but is time- and cost- intensive, leading us to explore an alternative technique. The purpose of this study was to assess the effectiveness of a new, anti-pronation (AP) taping technique, as compared to the ALD, to (a) reduce or prevent ND and (b) cause a lateral shift in the center of pressure (COP) measures. Methods: This is a 2 (tape techniques) by 3 (time: baseline, tape/pre-exercise, and tape/post-exercise) controlled laboratory study design. Twenty symptomatic (ND >/= 10 mm) college-age subjects were prepared with one of the 2 tape techniques and/or control and performed the ND test three times and walk across a pressure mat five times. Then the participants fatigued the tape by walking on a treadmill for 15 minutes at 3.0 mph at 0% grade and ND and pressure mat readings were recorded again. A within and within ANOVA allowed for the examination of between and within comparisons and a functional analysis (lateral shift as a function of time) on the mat-generated data were done p<.05. Results: Results revealed significant differences across times, and a times-by-tape technique interaction but differences between tape techniques were not significant. M and SD and indicate that while both taping techniques reduced ND, only the AP technique was significantly different (HSDTukey (3,76)=1.44, p<.01) for every comparison other than AP pre-exercise, the mean lateral shift for the treatment was not significantly different from the control across any part of the normalized stance phase, but was significantly lower than the control in the 30-90% interval in the AP pre-exercise. Discussion: The AP technique not only controlled ND but also resulted in an increase in lateral excursion of the COP line during that portion of the stance phase associated with the structures and functions of the TP. Both techniques can be appropriately used but that the AP can be used with more confidence in its effectiveness. The MatScan has allowed examination of forefoot pronation in the horizontal plane, not just the vertical plane, yielding a more holistic analysis of forefoot pronation. Being able to analyze data in a functional fashion (i.e., lateral shift as a function of time) could allow researchers greater insights to the complex relationships between biomechanical movement and appropriate interventions.
408

Relationship Between Total Body Mass, Fat-Free Mass, Fat Mass, and Bone Mineral Density of the Hip In Middle-Age Women: The Roles of Diet, Physical Activity, and Menopause

Fosson, Elizabeth Reid 31 July 2012 (has links) (PDF)
Objective: This study was conducted to investigate the relationship between hip bone mineral density (BMD), fat free mass (FFM), fat mass (FM), and total body mass (TBM) and the extent to which these relationships were modified by various confounding factors. The cross-sectional analysis included 262 healthy females (mean age 41.6±3.0 years). Methods: BMD of the hip and body composition were assessed by the Hologic 4500W dual energy x-ray absorptiometry (DXA) system. Total and intensity of physical activity (PA) were objectively measured using an Actigraph accelerometer. Dietary calcium and vitamin D from food and beverages, as well as from supplements, were measured separately using the Block food frequency questionnaire. Menopause status and prescription bone drug use were measured by a questionnaire. Results: The relationship between FFM and hip BMD was strong and robust (F=24.5, P<0.0001). Using the pooled standard deviation revealed a large effect size of 1.2 when comparing hip BMD of women with low FFM and high FFM. Potentially confounding variables, considered individually and collectively, did not change this relationship. The association between FM and hip BMD was also substantial (F=9.9, P<0.0001) and remained significant when controlling for all potentially confounding variables, except differences in FFM. The relationship between TBM and hip BMD was also strong and dose-response (F=21.5, P<0.0001) and remained significant, except when differences in FFM were controlled. Conclusion: The relationships between body mass (total, fat, and fat free) and BMD of the hip in middle-age women are strong and significant. The associations are not influenced by differences in age, height, menopause status, calcium or vitamin D intake, volume or intensity of PA, or the use of bone enhancing prescription drugs. The findings suggest that women with low body mass, particularly low FFM, tend to have low hip BMD and there is little that can be done to change this association.
409

mTOR Pathway Activation Following Resistance Exercise with Vibration in Human Subjects

Leavitt, Michael G. 07 March 2013 (has links) (PDF)
Functional adaptations in human skeletal muscle following a period of resistance exercise are the result of regular activation of cellular signaling pathways that elevate muscle protein synthesis. It has been reported that the addition of whole body vibration (WBV) to a resistance exercise program enhances performance. Such improvements in muscle function may be the result of increased activation of cellular signaling pathways associated with muscle growth. Purpose: We have investigated whether an acute bout of resistance exercise in combination with WBV results in a greater activation of the mTOR signaling pathway compared to resistance exercise alone. Methods: Eight untrained college-age males (23 ± 2 yrs, 179 ± 1 cm, 75.0 ± 2.5 kg, and 12.6 ± 1.8% body fat) performed unilateral leg press exercises with (Vbx) and without (RT) vibration. Muscle samples were obtained from the vastus lateralis muscle pre-exercise (baseline) and one-hour following the bout of resistance exercise. Muscle tissue samples were analyzed for phosphorylated levels of mTOR, p70S6K, and 4E-BP1 proteins. Results: One-hour following the resistance exercise bout there were no differences between phosphorylated levels of mTOR or 4E-BP1 in Vbx or RT (p > 0.05). Levels of phosphorylated p70S6K were increased at the one-hour post-exercise time-point in both Vbx (baseline: 504 ± 286 OD; post: 5039 ± 2351 OD, p < 0.05) and RT (baseline: 356 ± 131 OD; post: 5430 ± 1218 OD, p < 0.05); however, there was no difference in protein phosphorylation levels between conditions (p > 0.05). Conclusion: Vibration does not augment acute activation of the mTOR signaling pathway in human skeletal muscle suggesting that performance benefits resulting from combining resistance exercise and vibration may not be the result of an enhanced cellular growth response.
410

A Comparison of Two Sock Types on Navicular Drop and Center of Pressure Measurements in Standing, Walking, and Running

Taylor, Ashlee 30 September 2013 (has links) (PDF)
Introduction: The New Balance Core Low Cut Sock (New Balance Athletic Shoe, Inc. · Boston, MA United States) is one of many arch support socks out in the market. These socks have an elastic portion, called a Stability Fit Arch Support & Hold technology, which has been incorporated into the arch area of the sock. The company makes the following claim that the socks provide, "Gentle compression to support the arch, relieving arch-related pain and discomfort."1 If these socks do provide adequate arch support, then they would allow individuals the ability to have an inexpensive method of arch support that is easy to apply and use. The purpose of this study is to test the effectiveness of these socks in (a) navicular drop (b) static pressure insole pressure profiles and (c) dynamic (walking and running) pressure insole pressure profiles. Methods: Eighteen symptomatic, college age (age 18-26) subjects were used in this study (seven male, eleven female), with symptomatic being defined as a navicular drop greater than or equal to 10 mm. Measurements were collected for both the navicular drop, and F-Scan insole data, for both static and dynamic stance. For walking and running trials, heel strike and toe off were identified by the Tekscan System and COP excursion coordinates evaluated throughout the stance phase. The COP coordinates were exported then compared over the stance phase. A series of functional analyses was used to assess the between group differences. A paired t-test was used to assess the within group differences. Results: Results indicate that the arch support socks were not significantly different from the control (regular socks) along any part of the foot strike (95% confidence) in any of the conditions (standing, walking or running). Results from the paired t-test revealed no significant differences in navicular drop between sock types (p = .379). Discussion: This study found that the elastic band in the New Balance socks did not provide increased support to the medial arch of the foot compared to the control sock in either the navicular drop paired t-test or the functional analysis of the static and dynamic data. The authors could not find any other comparable study on these kinds of socks. Compared to other reports, using both orthotic inserts and tape, ND was reduced, unlike the results found in the present study. 2 Our data are inconsistent with the idea that increased elastic support to the midfoot by these socks provides significant arch support. The authors would suggest another form of arch support such as orthotics or taping to aid on arch support rather than these socks.

Page generated in 0.058 seconds