The abstract is available in the Medicine & Sports & Exercise.

No description available.

No description available.

No description available.

No description available.

Osteoporosis (OP) is a disease characterized by low bone mass and structural breakdown of the skeleton. The disease may be prevented through weight-bearing, moderate to vigorous physical activity (MVPA), which is important for peri- and postmenopausal women who are at great risk for OP. However, most women do not participate in activity according to guidelines, which can negatively impact bone health. A better understanding of multidimensional factors that influence MVPA may help inform physical activity interventions aiming for OP prevention. The purpose of this study was to utilize social cognitive theory (SCT) to understand the associations between social cognitive factors and MVPA among peri- and postmenopausal women. Eighty-seven peri- and postmenopausal women (aged 43 to 65) completed this study. Participants completed demographic, health, calcium, and SCT questionnaires. SCT variables assessed included task self-efficacy (SET) and barrier self-efficacy (SEB), perceived social support from friends (SSFR) and family (SSFA), and perceived access to facilities (ACF) and home equipment (ACH). Participants wore an NL-1000 pedometer for one week to assess total steps per day and minutes spent in MVPA. Past year MVPA, past week leisure MVPA, and past week occupational/ transport MVPA were assessed with the Modifiable Activity Questionnaire. Stepwise regression analysis was used to identify the direct relationships between cognitive variables and each of the physical activity outcome measures. Moderation-mediation analysis was conducted to determine if significant interaction effects or confounding effects existed between social cognitive variables and each physical activity variable. Age, income, BMI, and highest level of education were controlled for in all analyses. Results showed significant relationships between social cognitive factors and each physical activity outcome, supporting the use of such variables for understanding physical activity behavior in peri- and postmenopausal women. For steps per day and MVPA minutes per day, 32% and 26% of the variance in activity was explained. For past year MVPA, past week leisure MVPA, and occupational/ transport MVPA, 39%, 26%, and 27% of the variance in activity was explained, respectively. The combination of variables entering the models was different for each physical activity outcome, but overall, SEB consistently emerged as the most prominent factor. Moderation analyses revealed a three way interaction effect between SEB, SSFR, and ACF for steps per day, and two-way interaction effects between SEB and SSFR for past year MVPA and past week leisure MVPA. Mediation analysis indicated SSFA confounded the relationship between SEB and past year MVPA. Results of this study indicate social cognitive factors are directly and indirectly associated with total and MVPA in peri- and postmenopausal women. These relationships should be considered when aiming to develop physical activity intervention programs for prevention of OP in peri- and postmenopausal populations.

Peak barbell velocity is an important determinant of weightlifting performance 2 . However, direct comparisons of this measure between elite men and women weightlifters is limited 7,8 . Therefore, the present study sought to establish a reference of the current status and trajectory of sexbased peak barbell velocity differences among elite weightlifters. This study examined performances of men and women in the 69 kg weight class in order to obviate the influence of body mass on performance. The purpose of this investigation was to help practitioners identify training needs of elite men and women weightlifters to improve weightlifting performance based upon between-group differences in peak barbell velocity.

Background: There has been very little research regarding the metabolic health of women during the postpartum period. Metabolic flexibility is the physiological ability to alter substrate oxidation in response to substrate availability and is a good indicator of overall metabolic health. Metabolic flexibility can be assessed by placing metabolic demands on the body and observing metabolic responsiveness- two examples of such metabolic stressors are lipid oxidation rates in response to a high-fat meal and as well as exercise. However, it is unknown whether postpartum women will respond similarly to these two different types of metabolic stressors. This information will allow researchers and clinicians to understand whether postpartum women can be considered more or less metabolically flexible based on one of these tests alone, or if both types of metabolic stress should be incorporated into research designs and/or clinical practice to fully understand one’s metabolic health during this critical time period. Objective: To determine the association between the metabolic responsiveness to a high-fat meal and a 30- minute continuous, moderate-intensity exercise among women during the sixth- month postpartum period. Methods: Seventeen healthy, postpartum women (age: 32 ± 4.5 year; body mass index: 24.74 ± 3.97 kg/m²) participated approximately six months after delivery. Metabolic measurements VO2 and VCO2 (L. min ̄ ¹) were measured and used to calculate the rates of lipid oxidation (g. min ̄ ¹) at baseline, two-hour post consumption of a high-fat meal and during a moderate-intensity exercise for 30-minutes. Results: A correlation was found between the lipid oxidation fold change in response to a high-fat meal and exercise (r= 0.45, p= 0.08; however, it was not statistically significant. There was a significant effect of time on lipid and carbohydrate oxidation rates (p<0.001) during baseline, after consumption of a high-fat meal and during a 30-minute exercise bout. Conclusion: A trending relationship was observed between the metabolic responsiveness to a high-fat meal and a 30-minute moderate-intensity exercise bout among women during the six-month postpartum

No description available.

Adult skeletal muscle is highly plastic and responds readily to environmental stimuli. One of the most commonly utilized methods to study skeletal muscle adaptations is immunofluorescence microscopy. By analyzing images of adult muscle cells, also known as myofibers, one can quantify changes in skeletal muscle structure and function (e.g. hypertrophy and fiber type). Skeletal muscle samples are typically cut in transverse or cross sections, and antibodies against sarcolemmal or basal lamina proteins are used to label the myofiber boundaries. The quantification of hundreds to thousands of myofibers per sample is accomplished either manually or semi-automatically using generalized pathology software, and such approaches become exceedingly tedious. In the first study, I developed MyoVision, a robust, fully automated software that is dedicated to skeletal muscle immunohistological image analysis. The software has been made freely available to muscle biologists to alleviate the burden of routine image analyses. To date, more than 60 technicians, students, postdoctoral fellows, faculty members, and others have requested this software. Using MyoVision, I was able to accurately quantify the effects of β-catenin knockout on myofiber hypertrophy. In the second study, I tested the hypothesis that myofiber hypertrophy requires β-catenin to activate c-myc transcription and promote ribosome biogenesis. Recent evidence in both mice and human suggests a close association between ribosome biogenesis and skeletal muscle hypertrophy. Using an inducible mouse model of skeletal myofiber-specific genetic knockout, I obtained evidence that β-catenin is important for myofiber hypertrophy, although its role in ribosome biogenesis appears to be dispensable for mechanical overload induced muscle growth. Instead, β-catenin may be necessary for promoting the translation of growth related genes through activation of ribosomal protein S6. Unexpectedly, we detected a novel, enhancing effect of myofiber β-catenin knockout on the resident muscle stem cells, or satellite cells. In the absence of myofiber β-catenin, satellite cells activate and proliferate earlier in response to mechanical overload. Consistent with the role of satellite cells in muscle repair, the enhanced recruitment of satellite cells led to a significantly improved regeneration response after chemical injury. The novelty of these findings resides in the fact that the genetic perturbation was extrinsic to the satellite cells, and this is even more surprising because the current literature focuses heavily on intrinsic mechanisms within satellite cells. As such, this model of myofiber β-catenin knockout may significantly contribute to better understanding of the mechanisms of satellite cell priming, with implications for regenerative medicine.