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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.
161

The Reproducibility and Validity of Using the Dmax Method to Predict Physical Working Capacity at Fatigue Threshold

Riffe, Joshua 01 January 2016 (has links)
Although the original (ORG) physical working capacity at fatigue threshold (PWCFT) assessment has demonstrated strong reliability and sensitivity to training and/or nutritional interventions, limitations may exist regarding the method of PWCFT estimation. However, a relatively new mathematical method, called Dmax, has been shown to be objective and reliable when estimating metabolic and neuromuscular fatigue thresholds. To date, however, no study has examined whether the Dmax method for estimating the work rate at PWCFT is similar to the ORG method. PURPOSE: The purpose of this study is to evaluate the reliability and validity of the Dmax-EMG method for estimating and tracking changes in PWCFT. METHODS: In the reproducibility study, 11 men (age: 21.9 ± 1.37 years; height: 175.6 ± 8.65 cm; body mass: 82.1 ± 13.92 kg) completed two incremental exercise tests (GXT) to exhaustion on nonconsecutive days. In the validity study, 11 active men (age: 23.4 ± 3.0 years; height: 177.9 ± 7.8 cm; body mass: 80.9 ± 10.7 kg) and 10 active women (age: 22.3 ± 3.1 years; height: 166.6 ± 9.5 cm; body mass: 62.8 ± 8.7 kg) volunteered to perform 12 sessions of high-intensity interval training (HIIT) over 4-weeks along with a pre- and post-training GXT to compare the Dmax to the ORG method of estimating PWCFT. RESULTS: The reproducibility study revealed no significant differences between the first (181.5 ± 29.2 W) and second (181.9 ± 26.18 W) GXT trials (p = 0.87). In addition, ICC3,1 resulted in 0.949 with an SEM of 6.28 W and a MD of 17.41 W. In the crossvalidation, the CE between actual and predicted PWCFT was not statistically different at pre (-6.7 W; p > 0.05) or post (-7.2 W; p > 0.05). Pre (r = 0.87) and post (r = 0.84) validity coefficients were considered very strong and the pre and post TE PWCFT values were 30.8 W and 32.5 W, respectively. Wide limits of agreement were calculated in the Bland-Altman analyses (pre: -68.36 to 54.93 W; post: -57.77 to 72.06 W) with no significant biases in both pre (-6.7 ± 30.8 W; p = 0.330) and post (-7.2 ± 32.5 W; p = 0.325). In addition, 95.2% and 100% participants fell within ±1.96 standard deviations of the mean difference for pre and post, respectively. CONCLUSION: Results of the study suggest that the Dmax method is both a reproducible and a valid method to estimate PWCFT when compared to the ORG method in young men.
162

Evaluation of Echogenicity Within and Between Ultrasonographic Images of the Vastus Lateralis

Varanoske, Alyssa 01 January 2016 (has links)
PURPOSE: The purpose of this study was to examine the echo intensity (EI) values of different ultrasound (US) images of the vastus lateralis (VL) using panoramic imaging in the transverse plane (PTI) and still imaging in the longitudinal plane (SLI). Secondary purposes of this study were to examine VL homogeneity and to determine relationships between subcutaneous adipose tissue thickness (SubQ) adjacent to the muscle and EI. METHODS: Twenty-four recreationally trained collegiate males (20.2 ± 1.6 years; height: 178.1 ± 6.6 cm; weight: 82.2 ± 13.4 kg) participated in this investigation. EI, cross-sectional area (CSA), muscle thickness (MT), and SubQ of the VL were assessed in the dominant limb (DOM) via three PTI and SLI. The best PTI was divided into three compartments of equal horizontal length (tertiles) to examine EI homogeneity. RESULTS: A repeated-measures ANOVA revealed a significant main effect for image/tertile between measures of EI (p < 0.001). The EI of PTI (57.976 ± 8.806 AU) was significantly lower than EI of SLI (65.453 ± 11.023 AU) (p = 0.002), however significant positive correlations existed between the two (r = 0.681; p < 0.001). Additionally, the EI of the SLI was significantly greater than the EI of the lateral tertile (58.717 ± 9.877 AU) (p = 0.001) and the EI of the posterior tertile (56.354 ± 9.887 AU) (p = 0.002). Although there was no significant difference between EI of the SLI and EI of the anterior tertile (59.065 ± 9.126 AU), a trend towards a significant difference was shown (p = 0.051). No significant differences in EI values between tertiles were identified. Significant differences in MT existed between PTI and SLI (PTI: 2.178 ± 0.367 cm; SLI: 2.015 ± 0.397 cm; p = 0.003), however MT values from PTI and SLI were significantly positively correlated with one another (r = 0.809, p < 0.001). Significant differences in SubQ existed between PTI and SLI (PTI: 0.217 ± 0.167 cm; SLI: 0.316 ± 0.225 cm; p < 0.001), however SubQ values from PTI and SLI were significantly positively correlated with one another (r = 0.915, p < 0.001). No relationship between EI and SubQ from either image was found (PTI and SubQ: r = -0.067, p = 0.754; SLI and SubQ: r = -0.114, p = 0.597). SLI yielded slightly lower standard errors of measurement (SEM) and coefficients of variation (CV), indicating better precision compared to PTI. CONCLUSIONS: EI of the VL appears to be homogeneous as assessed in a PTI in recreationally-trained collegiate males. Additionally, PTI and SLI yield different EI, CSA, MT, and SubQ values, but these values are highly correlated. The use of SLI requires less time, equipment, and technical expertise, and therefore may be advantageous for use in future studies.
163

Effects of an Acute High-Volume Isokinetic Intervention on Circulating Levels of TNF-α and STNFR: Influence of Age

Arroyo Delgado, Eliott 01 January 2017 (has links)
The immune system has been implicated in recovery and muscle regeneration following exercise. In response to muscle damage, the immune system responds with an increase in circulating pro-inflammatory cytokines with the goal of recruiting leukocytes to the damaged area. Tumor Necrosis Factor-alpha (TNF-α), in particular, has been shown to be implicated in both muscle regeneration and muscle wasting. However, it remains unclear whether TNF-α is responsible for the age-related losses in muscle size and function. Also, due to the high clearance rate of TNF-α from circulation, analyzing the circulating levels of soluble TNF-α receptors 1 and 2 (STNFR1 and STNFR2) may provide a better indication of inflammatory events. Therefore, the purpose of this study was to compare changes in circulating levels of TNF-α, STNFR1, and STNFR2 following an acute muscle damaging intervention in young age (YA) and middle-aged (MA) males. Recreationally active young (YA; N=9, 21.8 ± 2.2 y, 179.5 ± 4.9 cm, 91.2 ± 12.2 kg, 21.8 ± 4.3% BF) and middle-aged (MA; N=10, 47.0 ± 4.4 y, 176.8 ± 7.6 cm; 96.0 ± 21.5 kg, 25.4 ± 5.3% BF) males completed an acute muscle damaging protocol (MDP). Blood samples were obtained at baseline (BL), immediately (IP), 30 minutes (30P), 60 minutes (60P), 120 minutes (120P), 24 hours (24H), and 48 hours (48H) post-MDP. Lower body performance was analyzed via isokinetic dynamometer at BL, IP, 120P, 24H, and 48H. No significant group x time interactions or main group effects were observed for TNF-α, STNFR1, STNFR2 or any marker of muscle damage. When collapsed across groups, plasma lactate was significantly elevated at IP (p < 0.001) and 30P (p = 0.003); serum myoglobin was increased at 30P (p = 0.002), 60P (p = 0.001), and 120P (p = 0.007); creatine kinase was elevated at 24H (p = 0.001) and 48H (p = 0.005). Plasma concentrations of TNF-α were unchanged following MDP. With both groups combined, serum STNFR1 was decreased at 30P (p = 0.001) and increased at 48H (p = 0.028). Serum STNFR2 was decreased at 30P (p = 0.008), 60P (p = 0.003), and 120P (p = 0.002). The results of this study indicate that the TNF-α and STNFRs response to exercise is similar between young and middle-aged males. Measuring STNFRs may be a more appropriate method of assessing the acute inflammatory response to muscle damage. In addition, an acute bout of exercise may attenuate ectodomain shedding of TNFR1 and TNFR2.
164

Effects of an Acute High-Volume Isokinetic Intervention on Inflammatory and Strength Changes: Influence of Age

Gordon, Joseph 01 January 2017 (has links)
PURPOSE: The purpose of this study was to compare the effects of a high volume isokinetic intervention on lower body strength and inflammation, as well as markers of muscle damage in the subsequent 48 hours between younger and middle-aged men. METHODS: 19 healthy, recreationally trained men were randomly assigned to two groups, younger adults (YA: 21.8 ± 2.0 y; 90.7 ± 11.6 kg; 21.5 ± 4.1 % body fat), or middle-aged adults (MA: 47.0 ± 4.4 y; 96.0 ± 21.5; 24.8 ± 6.3 % body fat). Both groups reported to the human performance laboratory (HPL) on four separate occasions. On the first visit (D1), anthropometric assessment, as well as a familiarization session with the isokinetic dynamometer, was performed. A muscle damaging protocol (HVP) was performed on the second visit (D2) consisting of 8 sets of 10 repetitions at 60°·sec-1 on the isokinetic dynamometer. An assessment protocol (AP) was performed to assess performance decrements between the YA and MA groups. For this protocol, a maximal voluntary isometric contraction (MVIC) was performed, as well as 3 isokinetic kicks at 2 different speeds (240°·sec-1 and 60°·sec-1). For the MVIC, values for peak torque (PKT), average torque (AVGT), rate of torque development at 100 ms (RTD100), and 200 ms (RTD200) were recorded. For the isokinetic kicks at 240°·sec-1 (ISK240) and 60°·sec-1 (ISK60), values were also recorded for peak torque (PKT), average torque (AVGT), as well as peak power (PP), and average power (AVGP). The AP was performed before the HVP (BL), immediately after the HVP (IP), 120 minutes after the HVP (120P), as well as one (24H) and two (48H) days following the HVP. Blood draws were also taken at BL, IP, 24H, and 48H, as well as 30 minutes (30P), and 60 minutes (60P) following the HVP to assess circulating levels of creatine kinase (CK), myoglobin (Mb), c-reactive protein (CRP), and interleukin 6 (IL-6). Ultrasound assessment was also performed at BL and IP as well to assess changes in muscle morphology as a result of the intervention. Performance, blood, and ultrasound markers were analyzed using a repeated measures ANOVA to observe between group comparisons for all of the outcome variables. RESULTS: There were no group differences observed for isometric or isokinetic peak torque or average torque, nor were there differences in isokinetic peak power or average power between the two groups as a result of the intervention. There were, however, differences in the pattern for rate of torque development at 100 ms and 200 ms between the two groups. RTD 100 was decreased at IP and 48H in YA, with MA showing decreases at IP, but also 120P and 24H unlike YA. RTD200 was decreased at all time points in YA, while MA was decreased at IP, 24H, and 48H, but not 120P. For markers of muscle damage and inflammation, there were no differences in the response of Mb, CK, CRP, or IL-6 between groups. CONCLUSIONS: Age does not appear to be a driving factor in the inflammatory or muscle damage response from a high volume isokinetic intervention. Though changes in peak torque and average torque from a high volume isokinetic intervention do not seem to differ between younger and middle-aged adults, the rate of torque production at 100ms and 200ms is different between groups. This suggests that while recovery to average or maximal strength after an exercise bout may not be affected greatly by age, the rate of neuromuscular recovery from exercise may be primarily affected by other factors such as training status.
165

DETERMINING OPTIMAL RESISTANCE LOADS DURING EXERCISE IN MALE AND FEMALE COLLEGE STUDENTS

Amo, Alexia 01 January 2021 (has links) (PDF)
Exercise is a crucial component in obtaining proper health and fitness objectives in young adulthood. Determination of an optimal resistance load for men and women may aid in physiological function and reduce the likelihood of injury. We tested 32 physically active men (n=14) and women (n=18) between ages 18-25 on Proteus Motion, USA. Proteus applies continuous three-dimensional magnetic resistance loads during exercise. Testing consisted of 2 repetitions of horizontal and vertical push and pull exercises comparing performance of the dominant and non-dominant arm. Each exercise was performed with a resistance of 7lb, 14lb, 21lb, and 28lb for a total of 32 repetitions. Proteus software calculates power, explosiveness, consistency, range of motion, and braking. Analysis of variance (ANOVA) with repeated measures tested differences in results at each resistance load. Power produced between sexes was similar in press motions but differed in pulls.
166

Professional Liability Insurance for Athletic Trainers: A Cross Sectional Study of Athletic Trainers Who Do Per Diem Work

Belgrave, Kameelah J 01 January 2020 (has links)
Context: Many secondary school athletic trainers (ATs) complete per diem work as a way to supplement their income. Working per diem means the AT provides services to events that are not part of their main employment. Since this type of work is not connected to their main employment, the AT may lack appropriate professional liability insurance (PLI). PLI is a type of insurance that protects healthcare professionals from bearing the entire cost of defending a malpractice claim made by a former or current patient. Anecdotally, many ATs believe that the PLI provided by their main employer covers all health care services they provide, although this is not typically the case. Working without PLI is a legally risky behavior for ATs because defense against a malpractice claim could lead to financial ruin. Objective: This study examined ATs knowledge about the importance of having PLI and situations where they remain unprotected. Design: Cross-sectional. Setting: Participants completed a web-based questionnaire. Patients or Other Participants: Responses from 66 secondary school ATs were analyzed. Main Outcome Measures: The web-based survey was distributed to evaluate the level of knowledge secondary school ATs have regarding PLI. Results: The questionnaire revealed that 86.4% (n=57) of the participants did per diem work at least once per year. Of those who participated in per diem work, 29.8% (n=17) stated they did not have PLI. The questionnaire also revealed that only 46.8% (n=29) of the participants reported always having a physician who oversees them and knows they are working a per diem event. In addition, only 22.6% (n=14) of the participants reported always having a written contract that delineates their responsibilities for a per diem event. Conclusion: Many ATs self-reported athletic training practices that are in violation of the Board of Certification (BOC) Standards of Professional Practice and in violation of state practice acts by working without physician oversight and without PLI during per diem and volunteer events. In addition, many ATs are practicing with suboptimal business standards by working per diem and volunteer events without a contract that delineates responsibilities or pay. ATs must understand the situations where they are in violation of the BOC Standards of Professional Practice, their state acts, and situations where they are putting themselves at risk. ATs should ensure they have privately purchased adequate PLI any time they provide care outside their main employment job description, such as when they work per diem or volunteer as an AT. If an AT provides athletic training services without PLI they are ultimately exposing their personal assets and financial stability if a malpractice claim is made against them.
167

Upright versus recumbent cycle ergometry using a modified Y-way protocol

Talbot, Shaun Marie 01 January 1994 (has links)
Because of its practicality, many exercise physiologists use the cycle ergometer to test cardiovascular endurance; yet due to physical injury or handicap, there is a great segment of our population that cannot easily manage an upright seated position. The recumbent position helps to stabilize the upper body, and therefore may help those whose repertoire of postural control is compromised. At present, the majority of studies dealing with upright and recumbent positions for graded exercise testing show the upright position to yield higher HR and VO2 readings. In order to determine the difference between the upright and recumbent cycle ergometer using the Y-Way Protocol, 41 healthy subjects (24 females, 17 males) performed GXT's in each position until HR reached 90% age-predicted max. Subjects were broken into two groups, with one group performing the recumbent test first and the other group performing the upright portion of testing first. Predicted . . and actual VO2 measurements were recorded for each subject, and maximum VO2 predicted. A 2x2x2 ANOVA was applied to the data to determine interaction and effects among position (upright vs. recumbent), protocol (YMCA and actual VO2), and gender. No differences in VO2 max between the upright and recumbent position were observed in either gender or protocol. It was determined that the recumbent position is a valid testing position in the estimation of VO2 max using workload adjustments determined by the Y -Way protocol.
168

Electromyographical Analysis of Barefoot Squat: A Clinical Perspective.

Brown, Sarah E. 11 May 2013 (has links)
The purpose of this study was to compare muscle activation in eight superficial lower limb muscles during execution of barbell back squats while in barefoot and athletic shoe conditions. It was hypothesized that greater muscle activity would be seen when squats were performed in barefoot conditions. Six participants were included in the study (means: 21.33±1.53 years, 170.45±11.33cm height, 69.85±12.46kg mass, 3.4±1.40 years training). Each met specific inclusion criteria. Participants came in three separate days for data collection (Day 1 – 1 repetition maximum [1RM] was determined, Day 2 – maximum voluntary contraction tests were held, Day 3 – squat tests performed with two footwear conditions). Squat tests were performed at 60, 70, and 80% of participants’ 1RM for each footwear condition and EMG data was recorded for these tests. Paired-sample T-tests were used to see if any differences were present between footwear conditions during eccentric and concentric phases of the squat, regardless of intensity. To test for differences between eccentric and concentric phases of the squat by intensity, 2x3 repeated measure ANOVAs were performed. Results showed some statistical difference between footwear conditions for two muscles in eccentric phase and no statistical significance for difference in concentric phase when compared without regard to intensity. When comparing footwear conditions at each intensity, main effects, as well as statistical significance, were found between footwear conditions in the eccentric phase. Main effects, but no statistical significance, were found in the concentric phase. The results indicate that EMG activity is greater for certain lower extremity muscles during the eccentric portion of a squat when under barefoot conditions.
169

An Examination of the Relationship Between Regional Sport Commissions and Organizational Structure

Unknown Date (has links)
The purpose of this research was to examine the differences in the organizational structure of Sports Commissions in the United States of America. This study also examined Sports Commissions according to general organizational characteristics. Further, this study attempted to classify Sports Commissions according to organizational structure. In addition, comparisons and contrasts regarding organizational structure were drawn between organizations that represent large and small geographic regions. The theoretical frameworks for this study were based within contemporary and traditional organizational theories. The literature was grounded in reference to similar studies and findings relative to management and legal interpretations of community supported sport in general, and within sport management frameworks in particular. While the significance of this study is revealed in the findings pertaining to the structure of Sport Commissions, greater implications relative to sport organizations and community sport development are also discussed. The subjects for this study were regional Sports Commissions of the United States of America considered 'active' members of the National Association of Sports Commissions (NASC) collective. The survey instrument contained three sections which addressed the areas of centralization, formalization, and complexity, in addition to a fourth section, which examined descriptive organizational characteristics. The components of centralization measured included information dissemination, information output, and control of information. The components of formalization included written job descriptions, written rules and procedures, and supervision of personnel. Complexity was measured using size of structure, and education and experience of employees. Organizational characteristics were assessed according to Commission type, financial components, and activities performed. Survey methods included both telephone and mail surveys. Of the 74 total Sports Commissions surveyed, 57 participated; producing a final overall return rate of return was 77.03%. Three types of analyses were conducted on the data. One, a descriptive evaluation of each component of the Sports Commissions profiles identified was conducted. Two, a SCOSS reliability correlation analysis within and between SCOSS components was analyzed. Finally, a comparison between the organizational characteristics and dimensions of organizational structure of Sports Commissions. Responses were also coded into two major groupings: those that represent larger markets, specifically greater than 1 million inhabitants; and those which represent smaller markets, specifically smaller than 700,000 inhabitants. There was no significant difference found in the degrees of centralization, complexity, and formalization for the organizations studied, which signals important considerations regarding the overall status of the organizational structure of Sports Commissions. Finally, important findings and implications related to the organizational characteristics studied was also revealed. / A Dissertation submitted to the Department of Sport Management, Recreation Management, and Physical Education in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2003. / June 19, 2003. / Sports Commissions, Organization Structure, Sport Management / Includes bibliographical references. / Charles Imwold, Professor Directing Dissertation; Joe Cronin, Outside Committee Member; Annie Clement, Committee Member; Cecile Reynaud, Committee Member.
170

Effect of Pseudoephedrine on 800-Meter Run Times of NCAA Division I Women Athletes

Berry, Caroline 01 December 2011 (has links)
Pseudoephedrine is an over-the-counter drug commonly used as a decongestant, but also thought to have ergogenic effects. The World Anti-Doping Agency (WADA) has prohibited large doses (> 150 μg∙ml-1) of pseudoephedrine, while the National College Athletic Association (NCAA) does not include it on the banned substance list. The purpose of this study was to examine the effect of body weight dosing of pseudoephedrine on 800-m run times of NCAA female runners. Fifteen NCAA female track runners volunteered to participate in the randomized, double blind, crossover design. In trials that were a week apart, participants were given both 2.5 mg∙kg-1 pseudoephedrine and a placebo. Ninety minutes post-ingestion, participants completed an 800-m individual time trial on an indoor track. Finishing time was recorded with an automated video timing device. Heart rate and anxiety state scores were recorded immediately after each trial. Finally, a urine sample was taken from 5 participants about 2 hr post-ingestion. Placebo and pseudoephedrine running times were compared using a iv paired t test. Heart rate and anxiety state scores were also compared using a paired t test. Fourteen runners completed both trials and one was an outlier, giving thirteen participants used for statistical analysis. Despite being dosed (144 mg ± 17 mg) well above normal therapeutic levels, there was no significant difference (p = 0.92) in 800-m times between the placebo (2:39.4 ± 9.6) and pseudoephedrine (2:39.4 ± 9.6) trials, in post-exercise heart rate (p = 0.635, pseudoephedrine = 177.9 ± 14.5 beats∙min-1, placebo = 178.4 ± 18.5 beats∙min-1), or in anxiety state levels (p = 0.650, pseudoephedrine = 38.4 ± 11.6, placebo = 38.1 ± 8.8). A 2.5 mg∙kg-1 dose of pseudoephedrine had no effect on 800-m run times in NCAA female runners, and did not raise urine levels above 150 μg∙ml-1. This raises the question as to why pseudoephedrine is a specified prohibited substance by WADA. (49 pages)

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