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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.

Evaluation of the Effects of Alpha Size on Explosive Ability, Strength, and IGF-1 Hormone Levels

LeBlanc, Nina R. 04 February 2016 (has links)
<p> Ergogenic aides are widely used by fitness enthusiast and athletes to increase performance. Alpha Glycerylphosphorylcholine (A-GPC) has demonstrated some initial promise in changing explosive performance. The purpose of the present investigation was to determine if 6 days of supplementation with A-GPC would augment isometric force production compared to a placebo. Thirteen college aged males (Means &plusmn; SD; Age: 21.9 &plusmn; 2.2 yrs, Height: 180.3 &plusmn; 7.7 cm, Weight: 87.6 &plusmn; 15.6 kg; VO2 max: 40.08 &plusmn; 7.23 ml O2*Kg-1*min-1, Body Fat: 17.5 &plusmn; 4.6 %) gave written informed consent to participate in the study. The study was a double blind placebo controlled, cross-over design. The participants reported to the lab for an initial visit where they were familiarized with the isometric mid-thigh pull in a custom squat cage on a force platform and upper body isometric test against a high frequency load cell, and baseline measurements were taken for both. The participant then consumed either 600 mg per day of A-GPC or placebo, and at the end of 6 days, performed isometric mid-thigh pull and an upper body isometric test. A one week washout period was used before the participants baseline was re-measured and crossed over to the other treatment. The A-GPC treatment resulted in significantly greater isometric mid-thigh pull peak force change from baseline (t= 1.76, p=0.044) compared with placebo (A-GPC: 98.8.&plusmn;236.9N vs Placebo: -39.0&plusmn;170.9N). For the upper body test, the A- GPC treatment trended towards greater change from baseline force production (A-GPC: 50.9&plusmn;167.2N Placebo: -14.9&plusmn;114.9N), but failed to obtain statistical significance (t=1.16, p=0.127). The study found that A-GPC is effective at increasing lower body force production after 6 days of supplementation. Sport performance coaches can consider adding A-GPC to the diet of speed and power athletes to enhance muscle performance.</p>

Testing Fitness-Related Phone Application Technology in Physical Activity Classes

Simonton, Angela Nicole 13 April 2016 (has links)
Many young adults are inactive (Centers for Disease Control and Prevention, 2010) and time spent on smartphones and applications (apps) is high (Pew Research Center, 2014; The Nielsen Company, 2014). Technology is often viewed as a barrier to health behavior, so seeking ways of using technology to facilitate physical activity (PA) and other health-related behaviors could be beneficial. The Social Cognitive Theory (SCT) framework was used to determine if the NexTrack smartphone app could increase PA behaviors and SCT-related constructs among university students in PA courses. Participants in the NexTrack app intervention group were hypothesized to report increased psychosocial and behavioral PA outcomes compared to students in the control condition. Using quasi-experimental design, university students (N=181) were randomly assigned to one of two groups during an eight-week intervention. The intervention group was introduced to NexTrack and asked to log PA while control participants used paper and pencil logs. All received an instructional presentation on goal setting and were emailed weekly reminders to log their activity. Each participant completed previously established surveys on self-reported PA behavior, self-efficacy (SE), and self-regulation (SR) at baseline and post-intervention. Descriptive statistics, bivariate correlation estimates, and internal consistency estimates were calculated. Main analyses included a series of 2 (gender: male; female) x 2 (group: intervention; control) x 2 (time: baseline; 8-weeks) repeated measures analysis of variance (RM-ANOVA) tests and follow-up mean comparisons to examine group differences. Findings revealed no significant differences in PA, SE, or SR as a result of the intervention. However, participants in the control group logged significantly more events than those in the intervention. Results can help guide technology use in PA courses. Findings revealed that incorporating the NexTrack smartphone app did not facilitate students PA or psychosocial related behavior. Although increases in SCT related constructs were not seen by the control group, it may be beneficial to incorporate paper and pencil logging for a comprehensive understanding of PA habits. Based on the findings, use of NexTrack did not facilitate SE, SR, or increases in PA. More research is needed to determine how to best use app technologies as facilitators of PA.

Cardiovascular and Autonomic Nervous System Function: Impact of Glucose Ingestion, Hydration Status and Exercise in Heated Environments

Early, Kate Suzanne 20 April 2016 (has links)
Cardiovascular function is under the influence of autonomic nervous system, both of which can be assessed non-invasively. The purpose of this dissertation was to examine these non-invasive markers of cardiovascular and autonomic function and their relationships with exercise training, glucose ingestion and hydration status. A series of three studies were conducted to gain insight to various influences on cardiovascular and autonomic function. The first study examined the influence of exercise training of brachial artery flow-mediated dilation (BAFMD) using meta-analytic techniques. Sixty-six studies included in the analysis demonstrated exercise training improves BAFMD compared to controls. Results indicated exercise training significantly alters BAFMD, a well-known factor associated with prevention of cardiovascular diseases. Exercise training interventions including greater intensity and duration may optimize increases in BAFMD. The second study observed glucose ingestion alters autonomic nervous system function, shifting the sympathetic/parasympathetic balance to higher sympathetic activity. Higher exercise intensity decreased fasting heart rate variability 24-hrs after cessation of exercise whereas lower exercise intensity did not alter heart rate variability. Acute exercise increased heart rate variability after an oral glucose tolerance test, but was not affected by exercise intensity. The last study determined the effect of chronic dehydration on cardiovascular and sweat responses during exercise in a heated environment. Dehydration altered blood and urine markers of hydration status, but did not change cardiovascular and sweat response to exercise in the heat. . In addition, BAFMD was related to the change in weighted skin temperature and body temperature during exercise in the heat, and increased LF/HF at rest was associated with increased peak heat storage. Together these data suggest resting cardiovascular health may influence the ability to thermoregulate during exercise in the heat.

Principal Motives of Positive Youth-Adult Relationships: A Model for Identifying the Motives of Adult Volunteers and Youth-Adult Relationships in Physical Activity-Based Youth Development Programs

Goudeau, Stephanie Marie 11 December 2015 (has links)
The field of positive youth development has evolved in response to the growing effort to provide youth with safe and healthful activities during leisure time. Physical activity-based youth development programs (PA-based YDPs) utilize a range of individual and team sports and physical activities as tools to simultaneously teach character development and physical skills for the acquisition of life skills. The intentional focus on positive youth development provides a suitable context for the development of a youth-adult relationship (YAR). The bonding between a youth and adult is critical to the development of adaptive responses and life skills which ultimately impact the functionality of youth in adulthood. There is a limited understanding of the relationship between characteristics of adults who volunteer in PA-based YDPs and characteristics of YARs. Due to the importance of establishing a positive YAR within a PA-based YDP, it is useful to consider how the motivation of adult volunteers is related to characteristics of positive YARs. The purpose of this dissertation was to examine the relationship between volunteer adult motives and characteristics of YARs. Two studies, one using quantitative methods and one using qualitative methods, addressed this general purpose. The quantitative study examined the relationship between adult motivations and characteristics of YARs by testing the proposed model, Principal Motives of Positive Youth-Adult Relationships Model. The qualitative study used a semi-structured interview protocol with 12 volunteer adult leaders to investigate the motives of adult volunteers and their perceptions of YARs established in PA-based. Results of the study did not support the hypothesized model; however, it did provide justification for refining the model to focus on one YAR characteristic (trust/respect) as it may relate to volunteer motivation. The study did provide evidence to support a relationship between the satisfaction of volunteer motivation and the development of YARs. Additionally, facilitators of YAR development focused on the presence of two YAR characteristics. Implications for the broad base of positive YDPs and youth sport settings along with directions for future research are included.

Neural Recovery Rates of Knee Extensors Following a Resistance Exercise Protocol

Polk, Darren Michael 10 May 2016 (has links)
Fatigue can manifest in the human body in a multitude of ways, one of these is neural-based fatigue. Neural-based fatigue occurs when the nerve fails to activate a muscle (Brooks et al., 2005). The purpose of this research is to investigate rates of neural recovery following a resistance exercise protocol. A pre-test consisting of a 5-second maximum voluntary isometric knee extension was performed. Next, each subject performed a resistance exercise protocol consisting of 5 sets of 10 repetitions of isokinetic knee extensions. Post-tests following the resistance exercise protocol consisted of 5-second maximum voluntary isometric knee extensions after 1, 5, 10, 15, 30, 45, 60, 90, and 120 minutes of sedentary rest. Following the exercise protocol, mean RMS values, mean EMG frequency, and median EMG frequency were not significantly impacted by the resistance exercise protocol (p > 0.05). Rates of neural recovery were unable to be determined from the muscular force and EMG data.

How do Social Norms Affect Physical Activity and Performance on an Endurance Task?

Randazzo, Keith David 01 August 2016 (has links)
Despite the extensive benefits associated with a physically active life style, less than 50% of US adults engage in recommended levels of physical activity (PA), so finding ways to structure environments to promote PA is an important concern. Social norms, conceptualized as an individuals perception of peer behavior, provide a framework for exploring factors that influence decisions to be physically active. Although researchers have investigated how social norms influence a variety of behaviors, the PA domain has not been fully explored. The focus of this dissertation is to apply social norms theories to investigate how normative information influences PA intentions and exercise behaviors. In the first study, using the Theory of Normative Social Behavior as a framework, interrelationships among social norms, exercise identity, group identity, outcome expectations, and PA intentions were explored in a correlational design. The focus was to explore the underlying mechanisms in the relationship between descriptive norms and PA intentions. College students (N=345) in an introductory kinesiology course completed validated surveys. Descriptive norms were related to PA intentions and this relationship was partially mediated by injunctive norms, outcome expectations, and group identity. Additionally, exercise self-identity fully mediated the relationship. The results highlight the importance of fostering high levels of exercise self-identity when structuring environments to promote PA. An experimental design was used in the second study to investigate the influence of positive and negative normative information on the performance of an exercise endurance task. College students (N=102) were randomly assigned to receive positive or negative normative information, or no information, concerning expectations for their performance. Individuals who received positive feedback performed better than those who received negative feedback and those who did not receive normative information. The provision of positive normative information also produced an increase in self-efficacy for the task. Taken together, the findings from these studies provide insight into ways that social norms should be structured to promote physically active lifestyles. A focus on positive normative information and promoting exercise self-identity are key factors in this process, and these studies suggest that understanding the role of self-efficacy is also an important concern.

Relationship Between Metabolic By-Products and Nervous System Failure/Fatigue

Farney, Tyler Mitchell 02 August 2016 (has links)
Fatigue has generally been defined as an acute impairment of exercise/sport performance that includes both an increase in the perceived effort necessary to exert a desired force or power output, and the inability to produce the desired force or power output. The majority of research to date looking at fatigue has focused upon substrate utilization, however, what is relatively unknown is the contribution the nervous system has upon fatigue. Therefore, the purpose of this dissertation was to investigate potential mechanisms that relate to neural fatigue. An additional purpose was to determine if there were any relationships between metabolic by-products and EMG characteristics following exercise. The first investigation sought to determine changes in EMG M-wave amplitude of the gastrocnemius following the calf raise exercise. There were no significant changes in M-wave EMG amplitude following exercise. The second investigation compared changes in muscle contractile properties and EMG characteristics of the VL, RF, and VM following a high-intensity exercise. There was a significant decrease in MDF of the VL only. Additionally, there was a decrease in peak force and rate of force development. The last investigation utilized the same exercise protocol as the second investigation, but added the supplementation of aspartate and sodium bicarbonate. Both supplements were effective in reducing ammonia concentrations following exercise. Additionally, supplementation with sodium bicarbonate resulted in an increase in rate of force development following exercise. As for EMG characteristics, there was a significant decrease in MDF for the RF, but not the VL. There were no significant changes in PF or EMG amplitude. Currently, no relationship between the metabolic and nervous systems during times of fatigue can be determined at this point.

An Ideal-Type through Innovation Diffusion: Recording the Construction History of Football Stadiums in the National Collegiate Athletic Association Division I Football Bowl Subdivision (FBS)

Tutka, Patrick Michael 04 May 2016 (has links)
Dr. John Bale (1984) argued sport scholars need to examine whether innovation diffusion occurred in sport. Rogers (1962, 2003) argued innovation diffusion process involves the following: 1) an innovation; 2) an available communication system(s); and occurs 3) over time; and 4) among members of a social system (p. 11). This project also adds geography as suggested by Bale (1984) and Hagerstrand (1952, 1953) to the study of innovation diffusion. The purpose of the current project is to examine whether innovation diffusion exists within the strong social system of college football. The study involves the collection of data on college football from 1869 to 2014 to examine whether the concept of diffusion of innovation theory can be found in Division I Football Bowl Subdivision (FBS). The investigation concludes that five stages exist concerning the development of the college football stadium. Stage One starts with the development of college football from its humble beginnings as temporary facilities until the development of Harvard Stadium, the first reinforced concrete and steel venue. Stage Two is the golden age of college football stadium construction as the innovation of reinforced concrete and steel diffused to universities around the United States. Stage Three acknowledges the innovations occurring during the Great Depression and how both federal and state governments invested in stadiums as part of public works projects. Stage Four examines technology innovations such as television, artificial turf, modern scoreboards, and luxury areas and their respective impacts on the stadium. The final stage, Stage Five, examines the additions of luxury spaces to almost every venue along with the development of the modern video board. This project finds innovation diffusion occurs throughout time within Division I FBS. The project also concludes that due to improved communications technology and easing of the travel challenges, traditional geography as discussed by Bale (1984) influenced innovation diffusion in the earlier stages (i.e., Stages One through Three) while virtual geography influences innovation diffusion in later stages (i.e., Stage Four and Five). The project also finds that renovation was more common than new construction and that rehabilitation occurs more than any other types of renovation.

An Investigation of the Generalizability of Buoyancy from Academics to Athletics

Victoriano, Jackie Rae 06 May 2016 (has links)
Buoyancy, the ability of an individual to handle everyday setbacks, has been applied successfully to academics, and has implications for performance and well-being. The purpose of this investigation was to determine if the concept of buoyancy can be successfully applied to the domain of sports (i.e., athletic buoyancy). This study sought to examine the relationship between academic and athletic buoyancy, as well as the efficacy of five sport-oriented predictors (5Cs), confidence, coordination (planning), commitment, composure (anxiety), and control, on both athletic and academic buoyancy. Sport club athletes (N = 285) aged 18 to 31 years completed a one-time survey assessing their athletic and academic buoyancy, as well as each of the sport-oriented 5Cs. Internal consistency of each subscale was examined with Cronbachs alpha estimates. Correlations and multiple linear regressions examined the relationship between academic and athletic buoyancy and the predictive utility of the 5Cs on athletic and academic buoyancy. Results indicated that each subscale showed moderate internal consistency (all Cronbachs alphas > .70), and that academic and athletic buoyancy were moderately correlated (r = .51, p < .001). The 5Cs model accounted for 26% of the variance in athletic buoyancy (F(5,277) = 19.00, p < .001, R2 = .26). Composure was a significant predictor in the model (β = .42, p < .001), while the other 5Cs were not: confidence ( = .12, p = .53), commitment ( = .11, p = .06), control ( = -.10, p = .08), and coordination ( = .09, p = .12). The sport-oriented 5Cs also significantly predicted 15% of variance in academic buoyancy, (F(5,276) = 10.03, p <.001), R2 = .15. Confidence ( = .18, p < .01) and composure ( = .27, p < .001) were significant predictors in the second model. These results indicate the potential for the construct of buoyancy to be generalized from academics to athletics, and that a multidimensional buoyancy structure may be possible. Competitive sport anxiety negatively affects both academic and athletic buoyancy, though the predictive influence varied by domain. These findings set the stage for the development of a comprehensive model of multidimensional buoyancy.

Class-Related Emotions in Physical Education: A Control-Value Theory Approach

Simonton, Kelly L 12 April 2016 (has links)
This study investigated a model of students control beliefs and task value in physical education (PE). Specifically, it examined relationships among students perceptions of their teachers communication and instructional clarity, control beliefs and values toward PE, and academic emotions. High school students (N= 529) completed valid and reliable instruments assessing perceptions of teacher characteristics, control, value, enjoyment, and boredom in PE. Descriptive statistics, bivariate correlations, and internal reliability estimates were calculated. A path analysis was used to test the hypothesis that teacher communication and clarity would be related to control-value appraisals which would in turn, positively predict enjoyment or boredom. Indirect effects of teacher variables and emotional experiences were also tested with the path analysis. Findings revealed a good fit of the proposed model (CFI = .99; TLI = .96; RMSEA = .069). Teacher clarity was a stronger predictor than teacher communication of both control (â= .28, p< .01, R2 =. 09) and value (â= .19, p< .01, R2 =. 07). Students value beliefs toward PE positively predicted enjoyment (â= .71, p< .001) and negatively predicted boredom (â= -.61, p< .001). Control beliefs negatively predicted boredom (â= -.13, p< .05). A total of 58% of the variance in enjoyment and 47% in boredom were explained in the model. This study provides information about establishing effective learning environments that help PE students experience more enjoyment and less boredom. The tenets of control value theory (Pekrun, 2006) were supported, suggesting the framework can systematically investigate student emotions in PE contexts. From a practical standpoint, the importance of instructional clarity in relation to student control and value beliefs in PE highlight the need for teachers to use a variety of clarifying strategies such as effective demonstrations, individual and group feedback, and redirection and refinement when students are confused. Clarity and content value are especially important for secondary PE because this can shape students healthy habits as they move into adulthood. Emotional experience is consequently an important outcome that can link to increases in learning and healthy habits outside of school.

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