No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

INTRODUCTION: Low energy availability and hypothalamic amenorrhea are both risk factors for developing insufficient bone mineral density (BMD) in young physically active women. The prevalence of osteopenia in women athletes is estimated to be between 22-50%. PURPOSE: Determine the effect of calorie restriction and hypothalamic suppression on bone strength and geometrical measures. METHODS: 30 female Sprague-Dawley rats, age day 23, were randomly assigned to a control (C, n=8) group that received daily saline injections (0.2cc) for 27 days and sacrificed at age day 50, or two experimental groups; delayed puberty (GnRH-a, n=14) that received daily injections of gonadotropin releasing hormone antagonist (GnRH-a, 0.2cc, dosage 0.2mg*kg-1) or food restricted and delayed puberty (FR-G, n=8) that received daily injections of gonadotropin releasing hormone antagonist and had a 30% caloric restriction (no deficit in micronutrients) based on the C group's average daily food consumption. All animals were sacrificed at age day of 50. RESULTS: Body weight on day of sacrifice of the FR-G was significantly lower than C (15%, p < 0.001) while GnRH-a was significantly higher than C (8%, p=0.013). The GnRH-a treatment was successful indicated by significantly lower uterine and ovary weights in both the FR-G and GnRH-a groups (p < 0.001). The percent muscle to fat ratio of the FR-G group was significantly higher than control (64%, p=0.038). There was no difference in absolute femoral peak moment, however when normalized for body weight the FR-G and GnRH-a groups were significantly higher than control (19%, p = 0.004 and 20%, p < 0.001 respectively). Cortical bone total area was significantly less in the FR-G group as compared to control (10%, p = 0.043) however, FR-G had a larger cortical thickness compared to control (15%, p = 0.036). In the trabecular both the GnRH-a and FR-G groups had a significantly lower percent bone volume per total volume (BV/TV) compared to control (p < 0.001). However, when normalized for body weight, the percent bone volume of the FR-G group was higher than both control (p = 0.046) and GnRH-a (p < 0.001). The structure was also affected, GnRH-a and FR-G had a higher structural model index (SMI) values than control (p = 0.002, p = 0.007). CONCLUSION: Hypothalamic suppression and caloric restriction before puberty reduced body weight, body fat, and muscle weight while increasing femoral peak moment relative to body weight and increasing cortical thickness in the femur while maintaining trabecular volume per body weight. These results could suggest bone strength is more correlated with body composition than hypothalamic function. / Kinesiology

This study examined the relationship between perceptions of masculinity and attitudes towards lesbians and gay men within an athletic context. Demographic information was utilized to ascertain if certain populations of people have more negative sentiments directed at LGBTQ-identifying individuals. The researcher used modified versions of Herek's Attitudes Towards Lesbian and Gay Men Scale (1984), and Snell's Masculinity Behavior Scale (2013). Surveys were distributed online and the researcher used SPSS to analyze the data. The results suggest that there is not a relationship between perceptions of masculinity and attitudes towards lesbians and gay participants in a sport context. League choice, gender, and sexual orientation were found to be statistically significant predictors of one's attitude towards gay men and league choice was found to be a statistically significant predictor of one's attitude towards lesbian women. Age was found to be a statistically significant predictor of one's beliefs about masculinity, with statistical significance within the subscales of Success Dedication and Exaggerated Self-Control and Reliance. Although statistically significant, the results are not surprising and are consistent with past research of similar populations. It is hoped that future research will include qualitative aspects to gain a better understanding of how non-heterosexual sport participants negotiate their sport and LGBTQ identities. / Kinesiology

Vascular aging has been implicated in the etiology of many vascular diseases. A common process linking the vascular aging to the development of vascular complications is the accumulation of senescent endothelial cells (ECs) in the vessel wall. Senescent ECs often exhibit the endothelial activation, a cell interactive pro-inflammatory and pro-coagulant state, which becomes a hallmark of early stage of atherosclerosis. Regular practice of aerobic exercise has been recognized as the single most effective non-pharmacological anti-aging intervention. While multiple factors play a role in bringing about the salutary effect of aerobic exercise, I hypothesized here that unidirectional laminar shear stress (LSS) is a prominent cellular mechanism responsible for the protective effect of aerobic exercise against vascular aging. In chapter 1, the purpose of study was to investigate the protective effects of LSS against EC senescence. In in vivo study, C57BL/6J mice were allowed for 4-week voluntary wheel exercise after a partial ligation surgery on the left carotid artery (LCA) as to induce a local intravascular disturbed flow. Right carotid artery (RCA) was used as an internal control. In in vitro studies, human umbilical vein endothelial cells (HUVECs) were preconditioned by being exposed to LSS for 36 hours (20 dyne/cm2 for 12 hours and 5 dyne/cm2 for 24 hours) using a cone-and-plate shear apparatus. EC senescence was induced by incubating cells in 100 μM H2O2 contained media for 1 hour followed by 72 hours of serial culture in normal growth media. For mechanistic studies, we used resveratrol (RSV) and sirtinol as a SIRT1 activator and a sirtuin deacetylase inhibitor, respectively. EC senescence was determined by the percentage of senescence-associated β-galactosidase (SA-β-gal) positive cells as well as the expression levels of cell senescence markers such as p53, p21, and p16. In in vivo study, en face SA-β-gal staining showed deposition of senescent cells only in the LCA but not in the RCA, suggesting a direct association of disturbed flow with vascular cell senescence. In in vitro studies, the number of SA-β-gal positive ECs and the expressions of p53, p21 and p16 were significantly increased in H2O2-induced senescent ECs. LSS pre-conditioned cells showed significant reduction in the expression levels of cell senescence markers. Furthermore, in senescent ECs, increased reactive oxygen species generation, decreased cell migration and angiogenic dysfunction were observed, which were improved by LSS pre-conditioning. The protective effect of LSS against EC senescence was completely abolished by SIRT1 inhibition. This study suggests that high-flow LSS on endothelial cells has protective effects against H2O2-induced senescence through a SIRT1-dependent mechanism. In chapter 2, the purpose of study was to investigate the effects of LSS on mitochondrial remodeling and endothelial activation. To investigate the effects of exercise on endothelial homeostasis, twenty one pre-hypertensives have performed supervised 6-month aerobic exercise training (AEXT). In in vitro studies, HUVECs were exposed to high-flow LSS using a cone-and-plate shear apparatus. Endothelial activation was determined by measuring released levels of endothelial microparticles (EMP). SIRT1 siRNA was used to determine the underlying mechanism. Circulating levels of microparticles released by activated (CD62E+) and apoptotic (CD31+/CD42a-) endothelial cells were significantly decreased after a 6 month supervised aerobic exercise training program in individuals with prehypertension. In cultured human endothelial cells, laminar shear stress reduced endothelial activation and apoptosis, which was accompanied by an increase in mitochondrial biogenesis through a SIRT1-dependent mechanism. RSV treatment showed similar effects. SIRT1 knockdown using siRNA completely abolished the protective effect of shear stress. Disruption of mitochondrial integrity by either antimycin A or PGC-1α siRNA provoked the activated- and apoptotic- statuses in endothelial cells. However, shear stress normalized these impairments. Collectively, these data demonstrate a critical role of endothelial mitochondrial integrity in preserving endothelial homeostasis. In chapter 3, the purpose of study was to investigate the combined effects of RSV and LSS on mitochondrial biogenesis in ECs. HUVECs were exposed to 20 μM RSV and/or LSS at 20 dyne/cm2. The levels of SIRT1, mitochondrial biogenesis factors and mitochondrial content were significantly increased in the treatment of high-flow LSS and the combined treatment of RSV and LSS. However, the additive effect of combined treatment on mitochondrial biogenesis was not found in ECs. Taken together, exercise-induced increased LSS protects against endothelial activation and premature endothelial senescence partly by SIRT1 activation and improving mitochondrial biogenesis in the vascular endothelial cells. These findings suggest that aerobic exercise is an effective strategy to prevent diseases related to vascular aging. / Kinesiology

The purpose of this study was to understand components of motivation, adherence, and self-efficacy in exercise programs in adults with autism spectrum disorder, as well as the barriers that affect exercise participation in this population. A mixed-methods approach was utilized with an online survey, semi-structured interviews, and brief behavioral intervention. The online survey consisted of 20 questions. Measures included demographics and questionnaires regarding the utilization of and beliefs regarding activity trackers. Participants were recruited through Temple University’s Disability Resources and Services and through the Department of Rehabilitation Sciences. Thirty-five (n = 35) responses were collected from participants aged 18-68 (age 34±14.77 years). It was important for the research team to understand if this population could benefit from exercise technology to help promote behavior change. Participants were females (54.3%) and males (45.7%), with 68.6% reporting Caucasian, 20% Asian, 2.9% Hispanic, and 8.6% other. Of the respondents, 40% were Temple University students and 60% were community members. A majority of participants (78.1%) reported that they do not currently use an activity tracker and 71% reported that they do not use a mobile application to track physical activity (PA); however, 73.5% reported that using an activity tracker would help to increase PA levels. Of the total participants who attempted the online survey (n = 35), 79.41% (n = 27) indicated interest in a follow-up interview. Semi-structured interviews were conducted with participants (n = 3) aged 19-53. Interviews were designed to further understand the PA levels of adults on the spectrum, as well as the attitudes and motivations toward PA. A version of the constant comparative method was used to identify 5 themes; exercise history, perceived barriers, environmental constraints, exercise demands, and how ASD affects exercise participation. From the 5 themes, 24 subthemes emerged based on interview responses. . Following the interviews, participants were provided a brief PA intervention. Two individuals aged 19-21 wore a Fitbit Flex 2 for a total of six weeks; exploring the potential to motivate persons with ASD to increase their PA levels using techniques such as goal setting and reinforcement. The research team designed this study using a pre-test post-test design. Overall, the step count and activity levels of both participants increased when comparing the pre-phase to the post-phase. However, no significance was found when running paired samples t-tests between pre-test and post-test PA results. These findings suggest that individuals with ASD do not exhibit statistically significant differences at pre-test or post-test. It is important to note that these results are not generalizable due to the small sample size. / Kinesiology