• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3165
  • 1913
  • 322
  • 290
  • 172
  • 158
  • 59
  • 52
  • 52
  • 52
  • 52
  • 52
  • 51
  • 32
  • 28
  • Tagged with
  • 8466
  • 1593
  • 1380
  • 1033
  • 890
  • 863
  • 850
  • 794
  • 792
  • 718
  • 716
  • 663
  • 648
  • 636
  • 630
  • 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.
131

Effects of Rest Position on Ultrasound-Derived Morphological Characteristics of the Vastus Lateralis and Lower-Body Force Production

Varanoske, Alyssa 01 May 2019 (has links)
INTRODUCTION: Ultrasound assessment of the lower body typically encompasses 10-15 minutes of supine rest prior to examination because of the potential influence of gravitational fluid shifts on tissue size and composition. However, examination of the vastus lateralis (VL) muscle requires individuals to lay in the lateral recumbent position, and this change in position may influence muscle morphological characteristics and their ability to predict muscle function. PURPOSE: The purpose of this investigation was to examine the effect of rest position on ultrasound-derived morphological characteristics of the VL and to determine whether or not rest position affects the relationships between muscle morphological characteristics of the VL and lower-body force and power production. METHODS: Thirty-one resistance-trained males (age: 23.0 ± 2.1 years; height: 1.79 ± 0.08 m; body mass: 87.4 ± 11.7 kg) participated in this investigation. Muscle morphological characteristics, including cross-sectional area (CSA), muscle thickness (MT), pennation angle (PA), echo intensity (UnCorEI), subcutaneous adipose tissue thickness (SFT), and EI corrected for SFT (CorEI) of the VL were assessed in the dominant limb after 15 minutes of rest in 3 recumbent positions: supine (SUP), dominant lateral recumbent (DLR), non-dominant lateral recumbent (NDLR), as well as after 15 minutes of standing (ST) and immediately after laying down (IP). Following ultrasound assessments, participants completed unilateral performance assessments, including vertical jumps (UVJ), isometric/isokinetic testing, and a 1-repetition maximum (1-RM) leg press. RESULTS: A repeated-measures analysis of variance revealed significantly different (p < 0.05) CSA, MT, PA, UnCorEI, and SFT in ST compared to recumbent positions after 15 minutes of rest (NDLR, DLR, and SUP). Additionally, significant differences were observed between recumbent positions for CSA, CorEI, and UnCorEI; however, no differences were observed for MT, PA, and SFT. Different magnitudes of relationships were observed between muscle morphological characteristics measured after rest in different positions and performance variables. However, muscle morphology after IP generally appears to be the best predictor of performance for most variables, although utilizing the NDLR and DLR positions may provide comparable, or potentially stronger results for variables such as IsokPF. The relationship between muscle morphology and various performance variables in ST were weaker compared to the recumbent positions examined, specifically for IsokPF, 1-RM leg press, and for all UVJ variables, except total work. CONCLUSIONS: Muscle morphology differs depending on the rest position utilized prior to ultrasound analysis. These rest positions also affect the ability for muscle morphology to predict lower-body force production. Future research should consider evaluation of muscle morphology of the VL after IP in the prediction of muscle function; however, NDLR and DLR may also be used. SUP and ST provide significantly weaker relationships for some performance variables compared to the other recumbent positions.
132

A Mixed-methods Approach to Understanding the Relationship Between Mental Toughness and the Effect of Music on Exercise Performance

Baker, Kayla 01 May 2019 (has links)
Previous research has investigated the use of music as an ergogenic aid for exercise performance; however, the effect of music on exercise may differ between individuals of varying levels of mental toughness (MT). Purpose: The purpose of this study is to examine the moderating effect of MT on the effect of listening to music during exercise. Methods: The current study used a counter-balanced design, utilizing a mixed-methods approach. Thirty-one recreationally-active individuals (22.13 ± 2.11 yrs, 1.73 ± .10 m, 75.68 ± 14.67 kg, 42.89 ± 5.31 mL·kg·min-1; 65.5% males) were recruited for this study. Participants completed an initial visit to complete a MT questionnaire and create a personalized music playlist of at least 15 songs. Participants completed two familiarization trials and a VO2max test on the treadmill, all on separate days. The experimental trials consisted of two separate conditions: 1) no music (NM); and 2) self-selected music (SSM). For each experimental trial, participants performed a time-to-exhaustion (TTE) run at 80% of their VO2max, separated by at least 48 hours, followed by a post-study interview. Pearson product-moment correlations were used to investigate relationships between performance variables and MT. Moderated regression analysis was used to determine a potential order effect, as well as a potential moderating effect of MT on change in performance between NM and SSM groups. Linear regression analysis was used to determine a potential relationship between MT and change in performance between NM and SSM groups. An alpha level of p ≤ 0.05 was used to determine statistical significance. All qualitative data from post-study interviews was transcribed, coded, and categorized into primary themes. All statistical analyses was conducted via the Statistical Package for Social Science (SPSS) software for Windows version 21 (SPSS Inc., Chicago, IL). Results: Averages were calculated for MT (156.39 ± 9.38), TTE SSM (14.18 ± 4.79 minutes), and TTENM (12.23 ± 5.24 minutes). Correlations were found between VO2max and TTESSM, TTENM, and MT (r = 0.390, p = 0.030; r = 0.519, p = 0.003; r = 0.404, p = 0.024; respectively). Moderated regression analysis revealed a non-significant interaction between MT, music, and order, indicating no order effect (β = -0.416, p = 0.735). Independent samples t-tests revealed no significant difference in MT, performance, or VO2maz between groups of participants who received music first or music second, indicating no effect of order (F = 0.388; p = 0.538; F = 0.537; p = 0.470; F = 0.070; p = 0.794; respectively. Moderated regression analysis, via linear regression, determined no significant moderating effect of MT on the change in performance between trials (ΔTTE) (F (3, 58) = 0.958, r = 0.217, p = 0.498). Linear regression, however, revealed a significant main effect of MT, indicating an inverse relationship between MT and ΔTTE (F (1, 29) = 4.417, r = -0.634, p = 0.044). Discussion: The results from the current study indicate that greater levels of MT were associated with less change between the two performance trials, however, there were no significant relationships between MT or performance with self-selected music. This finding suggests that individuals with greater MT may demonstrate consistent patterns of performance, irrespective of the presence of external factors. Understanding the effects of MT and how external and internal stimuli affect performance may allow exercise professionals to tailor their training or rehabilitation programs to each individual, therefore increasing exercise performance and adherence.
133

The Effects of a 10-week Judo Program on Cortisol and Stress in Children with Autism Spectrum Disorder

Renziehausen, Justine 01 May 2019 (has links)
Children diagnosed with Autism Spectrum Disorder (ASD) often have increased levels of stress, leading to dysregulated production of cortisol. Elevated levels of cortisol have numerous known adverse health consequences, and therefore, interventions should be established to help attenuate cortisol production. As judo combines physical activity and mindfulness practice, it may aid in stress reduction and decreased levels of cortisol. Purpose: To examine the effects of a 10-week judo program on stress reactions and salivary cortisol levels in youth with ASD. Methods: 20 children with ASD participated in the 10-week judo program. Changes in acute (before and after one judo session) and chronic salivary cortisol levels were assessed at baseline and post intervention. Parents of participants were asked to complete the Stress Survey Schedule (SSS) to determine severity of stress reactions. The SSS consists of 10 subscales: changes, anticipation, unpleasant, positives, food related, rituals, social/environmental, sensory/personal, fears, and life stressors. Sleep quality was assessed via Actigraph GT9X accelerometers over a 7-day period at baseline and post-intervention. Paired samples t-tests were used to determine differences SSS pre/post-intervention. Repeated measures ANOVA was conducted to determine differences and in cortisol levels before and after one judo session and pre and post-intervention. Spearman correlations were used to determine correlations between sleep quality and subscales of the SSS. Results: Although not statistically significant, a trend was noted indicating a decrease in cortisol levels following one judo session (p=.057). Nonsignificant reductions in the subscales "changes (p=.14)" and "unpleasant (p=.12)" of the SSS were also observed. Conclusion: Acute changes in cortisol levels may be seen following one session of judo. Subscales of parent-reported questionnaire may also show improvements following 10 weeks of participation in a judo program.
134

The Impact of Judo on Aggressive Behaviors in Youth with Autism Spectrum Disorder

Rivera, Paola 01 May 2019 (has links)
The aim of this study was to examine the effects of an 8-week judo program on lifestyle habits and behavior in children with Autism Spectrum Disorder (ASD). METHODS: Participants included 25 children (ages 8-17), with a formal diagnosis of ASD. The sample participated in an 8-week judo program (45 minutes, 1x week), with measures taken at baseline and at the end of the 8-weeks. In order to assess activity levels and sleep quality, participants were instructed to wear Actigraph GT9X Accelerometers for 7 days and nights. In order to assess behavioral changes, parents were given the ABC survey to fill out at baseline and post-intervention. Non-parametric paired t-tests were conducted to compare differences in behaviors, MVPA, SB, and sleep quality (i.e. sleep efficiency, total sleep time, number of awakenings, and wake after sleep onset) pre and post judo. RESULTS: Results indicated there was a strong negative correlation (r= -0.632) with inappropriate behaviors and the number of classes attended. Participants also spent a significantly greater percentage of time in daily MVPA (8% vs 4%, p=0.05) following the program. There was a significant increase in total minutes of sleep duration (572.56 vs 333.8, p=0.008) following the program, and although not statistically significant, a trend existed for improved sleep efficiency (92% vs 88%, p=0.1). CONCLUSION: Despite no significant differences in ABC scores pre and post-judo, a strong association between class attendance and lower ABC scores were observed, along with improvements in MVPA and sleep quality. Future studies should include larger samples of youth with ASD, over a longer intervention period.
135

Changes in Running and Multiple Object Tracking Performance During a 90-minute Intermittent Soccer Performance Test (iSPT): A Pilot Study

Girts, Ryan 01 January 2018 (has links)
Multiple object tracking (MOT) is a cognitive process that involves the active processing of dynamic visual information. In athletes, MOT speed is critical for maintaining spatial awareness of teammates, opponents, and the ball while moving at high velocities during a match. Understanding how MOT speed changes throughout the course of a competitive game may enhance strategies for maintaining optimal player performance. The objective of this study was to examine changes in MOT speed and running performance during a 90-minute intermittent soccer performance test (iSPT). A secondary purpose was to examine the relationship between aerobic capacity and changes in MOT speed. Seven competitive female soccer players age: 20.4 ± 1.8 y, height: 166.7 ± 3.2 cm, weight: 62.4 ± 4.0 kg, VO2max: 45.8 ± 4.6 ml/kg/min-1 ) completed an intermittent soccer performance test (iSPT) on a Curve™ non-motorized treadmill (cNMT). The iSPT was divided into two 45-minute halves with a 15-minute halftime [HT] interval, and consisted of six individualized velocity zones. Velocity zones were consistent with previous time motion analyses of competitive soccer matches and based upon individual peak sprint speeds (PSS) as follows: standing (0% PSS, 17.8% of iSPT), walking (20% PSS, 36.4% of iSPT), jogging (35% PSS, 24.0% of iSPT), running (50% PSS, 11.6% of iSPT), fast running (60% PSS, 3.6% of iSPT), and sprinting (80% PSS, 6.7% of iSPT). Stand, walk, jog and run zones were combined to create a low-speed zone (LS). Fast run and sprint zones were combined to create a high-speed zone (HS). MOT speed was assessed at baseline (0 min.) and three times during each half of the iSPT. Dependent t-tests and Pearson correlation coefficients were utilized to analyze the data. Across 15-minute time blocks, significant decreases in distance covered and average speed were noted for jogging, sprinting, low-speed running, high-speed running, and total distance (p's < 0.05). Players covered significantly less total distance during the second half compared to the first (p = 0.025). Additionally, significant decreases in distance covered and average speed were observed during the second half for the sprint and HS zones (p's ≤ 0.008). No significant main effect was noted for MOT speed across 15-minute time blocks. A trend towards a decrease in MOT speed was observed between halves (p = 0.056). A significant correlation was observed between the change in MOT speed and VO2max (r = 0.888, p = 0.007). The fatigue associated with 90 minutes of soccer specific running negatively influenced running performance during the second half. However, increased aerobic capacity appears to be associated with an attenuation of cognitive decline during 90-minutes of soccer specific running. Results of this study indicate the importance of aerobic capacity on maintaining spatial awareness during a match.
136

Minimal Effects of Moderate Normobaric Hypoxia on the Upper-Body Work-Time Relationship in Recreationally-Active Women

Starling-Smith, Tristan 01 January 2018 (has links)
PURPOSE: To evaluate the effects of moderate normobaric hypoxia on the parameters of the work-time relationship during upper body exercise in women. METHODS: Thirteen recreationally active women (age: 22.7 ± 2.6 y; height: 167 ± 8.6 cm; weight: 66.4 ± 9.7 kg; body fat: 27.6 ± 5% body fat) completed a graded exercise test in both normobaric hypoxia (H; FiO2=~14%) and normoxia (N; FiO2=~20%) to exhaustion on an arm ergometer to determine V̇ O2peak and peak power output (PPO). Each participant completed four constant work-rate arm-cranking tests at 90-120% PPO in both environmental conditions. Linear regression was used to estimate CP and AWC via the work-time relationship during the constant work-rate tests. Paired samples t tests compared mean differences between V̇ O2peak, PPO, CP and AWC between conditions (N vs. H). Two-way (condition × intensity) repeated measures ANOVA was used to compare total work and time-to-exhaustion. RESULTS: H significantly reduced VO2peak (N: 1.73L/min ± .31L/min vs. H: 1.62L/min ± .27L/min, (p=.008) but had minimal effects on PPO (N: 78.08W±14.51W vs. H: 75.38W±13.46, p=.089), CP (N: 57.44W±18.89W vs. H: 56.01W±12.36W, p=.546), and AWC (N: 4.81kJ±1.01kJ vs. H: 4.56kJ±.91kJ, p=.510). No significant condition × intensity interactions were noted for total work or time-to-exhaustion (p > .05). CONCLUSIONS: Moderate normobaric hypoxia significantly reduced VO2peak but had minimal effects on CP and AWC using the work-time model.
137

Medical Claims at NCAA Institutions: The Athletic Trainer's Role

Killinger, Tyler P 01 January 2016 (has links)
Context: National Collegiate Athletic Association (NCAA) institutions are required to certify insurance coverage of medical expenses that result from athletically related injuries sustained while partaking in an NCAA event. This means that the student-athlete must be covered either by their parent’s/guardian’s insurance, their own personal insurance coverage, and/or the institution’s insurance program. Institutions assign this role to a variety of employees, including head athletic trainers (ATs), assistant ATs, athletic administrators, business managers, secretaries, or other institution employees. In 1994 Street, Yates, Lavery, and Lavery observed that the head AT was responsible for administering medical insurance/claims payment at 51% of the institutions studied. The tasks necessary to pay athletic medical claims require a lot of paperwork and can be very time consuming. Additionally, insurance rules and regulations are complicated. Anecdotally, ATs do not always feel well suited to perform these tasks. Objective: Investigate the ways that athletic associations/departments coordinate athletic medical claims and how often an AT is assigned to be the administrator who oversees policies and procedures related to athletic medical claims. Design: Cross sectional. Setting: Participants completed a web-based questionnaire. Patients or Other Participants: Responses from 184 (38%) ATs employed in collegiate settings (Division I 26.1%; Division II 28.8%, Division III 45.1%) were analyzed. Intervention: None. Main Outcome Measures: Demographics. Results: The mean number of full-time ATs on staff was 3.8 (n=97). The head AT was primarily responsible for the payment of athletic medical claims at 48.4% (n=89) of institutions and the assistant AT was responsible at 13.6% (n=25) of institutions. A non-AT was responsible at 38% (n=70). The mean hours spent on this task by head ATs (n=86) was 6.17 hours per week and the mean hours spent by assistant ATs (n=22) was 10.32 hours per week. Most respondents (62.0%, n=103) reported no formal training in athletic medical insurance claims payments whereas 20.5% (n=34) reported the individual responsible had had formal, with 17.5% (n=29) stating they were not sure what training the individual had received. When asked where they felt it was most appropriate to learn these concepts, respondents reported: within an accredited AT program curriculum (36% n=56), on the job training (34% n=52), or CEU event (30% n=46). Conclusions: It is clear that ATs at NCAA institutions are responsible for the administration of athletic medical claims. ATs are spending a large amount of time each week on medical claims, although most have no formal training. An AT may not be the most ideal individual to handle these medical claims; but if an AT is going to continue to be responsible for this task, AT programs should increase the emphasis of this content within the curriculum and CEU opportunities should be made available to ensure athletic medical claims are handled effectively.
138

A comparison of anatomical and physiological dead space during voluntary hyperventilation and exercise /

Bartels, Robert Louis January 1961 (has links)
No description available.
139

Fractional volumetric changes in the ultrastructure of sarcoplasmic reticulum in rat skeletal muscle due to chronic exercise /

Cirrito, James Frank January 1979 (has links)
No description available.
140

The metabolic effects of a seven week aerobic interval training program /

Doe, Robert Drury January 1970 (has links)
No description available.

Page generated in 0.0453 seconds