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Background: The health benefits of regular physical activity are well known and include the prevention of chronic diseases such as obesity, type 2 diabetes, and cardiovascular diseases. Still, only 20% of U.S. adults report meeting the Physical Activity Guidelines for Americans. With approximately 43% of U.S. jobs considered sedentary, there is a need for effective workplace physical activity interventions. MapTrek is a mobile health game designed to increase daily physical activity in a low-cost, scalable, and enjoyable way. Objective: The purpose of the present study was to test the efficacy of MapTrek for increasing daily steps and moderate-intensity steps over 10 weeks in a sample of sedentary office workers. Methods: Participants included 144 full-time sedentary office workers ages 21-65 who reported sitting at least 75% of their workday. Each participant received a Fitbit Zip to wear daily throughout the intervention. Participants were randomized to either a: 1) Fitbit only group or 2) Fitbit + MapTrek group. Physical activity outcomes and intervention compliance were measured with the Fitbit activity monitor. Results: The Fitbit + MapTrek group significantly increased daily steps (+2,091.5 steps/day) and active minutes (+11.2 minutes/day) compared to the Fitbit only arm. Conclusions: These data support MapTrek as an effective approach for increasing physical activity at a clinically meaningful level in sedentary office workers.

The purpose of this study was to explore awareness and opinions about sugar-sweetened beverage policy—specifically pouring rights contracts—on a university campus. Participants were 915 students, staff, and faculty currently studying or under employment at the University of Iowa. Participants completed an online survey. Nearly two-thirds (64.2%) of participants reported not being aware of pouring rights prior to completing the survey. Over one-third (38.0%) of participants reported they agreed with universities engaging in pouring rights contracts, while 30.9% of participants neither agreed or disagreed, and 31.0% disagreed with universities engaging in pouring rights contracts. Respondents who identified as male, undergraduate students, and those who agreed that individuals are responsible for their own sugar-sweetened beverage consumption were more likely to support engaging in pouring rights contracts. Understanding awareness, support, and determinants of support for pouring rights contracts is important for those involved in establishing policies targeting sugar-sweetened beverage availability on college campuses.

Visual analysis of an object's size can be used to determine the lifting forces we program to lift the object so that the resulting movements achieve the goals of the lift. These forces are scaled or specified prior to the object moving, that is, before sensory feedback information about the object's weight is available. Sensorimotor memories are relied on to provide relevant information about an object's density and weight if the object was previously manipulated. It is well established that young adults accurately scale their forces based on visual size cues. The purpose of this study was to determine if old adults scale their forces to the size of the object or if they rely on sensorimotor memory of the previous object's weight. There are reports of impaired visuomotor programing for grasp and lift in old adults. In the present study old and young subjects were required to lift four different sized bottles of constant density from a force plate and then place the object on a shelf. Two experiments were performed. Experiment one featured blocks of lifts for three bottles in the following order: large, small and medium. Experiment two took place fifteen minutes after experiment one and featured a bottle slightly larger than the medium bottle used at the end of the experiment one. The second experiment addressed whether imperceptible changes in size cause changes in predictive force scaling. Peak load force rate in the first force pulse (prior to lift-off) was measured for each lift of the objects with the focus being on the initial and last lift of each bottle. Both experiments presented a significant effect for bottle size on lift force rates. This result was found regardless of age. It provides additional support that young adults accurately scale their lift force rate based on the visual size cues of the object. Old adults also demonstrated scaling of their lift force rates based on bottle size which failed to support the hypothesis that old adults would merely reproduce their lift force rates from the previous lift with a different object. While both young and old scale lift forces to object size, the old demonstrated a trend for utilizing high lift force rates throughout the experiment as well as greater differences in lift force rate between the initial lift with an object and the final lift with the same object. Most subjects utilized a target strategy in which they produced a single peak lift force rate pulse. This is indicative of a neural representation of the weight of the object being utilized to program the lift force rate. The remaining subjects exhibited a probing strategy that features several step-wise increases in lift force rate until the object is lifted off. This represents a more cautious approach to lifting novel objects. Our results indicate that old adults, much like young adults, are able to scale their forces based on visual size cues.

On August 4, 2012, white American swimmer Michael Phelps was awarded a Lifetime Achievement Award by the international swimming federation in recognition of his Olympic achievements. The unprecedented award – a specially commissioned sculpture – proclaimed Phelps as “the greatest Olympian of All Time.” This title may, at one level, be perceived as a benign honorific bestowed upon an extra-ordinary athlete. On another level, the title should be viewed as a result of the hidden ideological work done by and through discourses of swimming in America, discourses that are always racialized, classed, nationalized, and gendered. Michael Phelps is the point of entry to unpack how modern sport and the Olympics reproduce these dominant views and processes that lead to contemporary social inequalities. My focus is an examination of the power relations that enabled and produced him as the Greatest Olympian of All-Time. Phelps’s phenomenal performance in the pool is undeniable, but I argue that the ensuing adulation and recognition results as much from his privileged position as a white American man as from his hard work, skill, and determination. This dissertation unpacks and explains how these processes work in the contemporary sporting world. Scholars have long argued that sport is a site for understanding how race, class, gender, and nationalisms are performed and/or constructed. In this dissertation, I take a critical cultural studies approach to demonstrate that, from an ideological and cultural point of view, Michael Phelps is the greatest Olympian of all time because he is the physical and symbolic embodiment of the modern Olympic movement, a movement founded upon 19th century ideals of humanism, liberalism, and modernity that continues to stabilize and reinforce dominant views of race, gender, class, nationalism and sexuality. To make this argument, I first historicize the sport of swimming itself. As one of the sports at the first Modern Olympics in 1896, swimming is an ideal site for understanding the modernization process through sport. Swimming has long been dominated by white athletes, and I deploy the recent concept of the sporting racial project to grasp how modernization is a racialized project fundamental to constructions of institutional racism. Next, I examine media representations of Michael Phelps in the early 21st century. These representations reveal the role of sport in popular imaginations of the nation and, specifically, the importance of the white male sporting hero in constructions of America in the post-9/11 world. Then, I explore and contextualize notions and meanings of “amateur” and “eligibility” within late 20th and early 21st century structures of Olympic swimming, including the complex and contradictory relationships between inter/national governing bodies. Finally, I show how these three seemingly independent processes involving race, class, gender, and nation are interdependent and fundamental to modern sport and the Olympics.

Macroautophagy, hereafter referred to as autophagy, is a catabolic process involving the degradation of cellular proteins and structures sequestered into a vesicle known as an autophagosome. The initiation of autophagy involves the conversion of a protein microtubule-associated proteins 1A/1B light chain 3B (LC3) from form I to form II allowing interaction with the formation of the autophagosome. Using an LC3-II/I ratio, relative initiation of autophagy can be estimated since higher relative amounts of LC3-II suggests a higher conversion rate of LC3-I to LC3-II, therefore suggesting autophagosomes are being formed at a higher rate. Autophagy’s selectivity, or its ability to degrade specific targets, is dependent on the degradation of ubiquitinated proteins and a protein adaptors, the latter forming a physical bridge between the ubiquitin-tagged cargo and LC3-II present on the forming autophagosome. Without these protein adaptors, autophagy has no selectivity and portions of the cytosol that happen to be near the autophagosome formation site are the only cellular components captured and degraded. Because the entire contents of the autophagosome are degraded following lysosome fusion, the selectivity can be assessed by determining the levels of protein adaptor and ubiquitinated proteins. Autophagy is constitutively active but is strongly stimulated under nutrient deprivation, such as fasting. Impairments of autophagy have been implicated in contractile and/or metabolic deficiencies in muscle diseases, obesity, diabetes, and aging; however, regulation of skeletal muscle autophagy is poorly understood at the molecular level. Here, we examined the role of the two partially homologous unc-51 like autophagy activating kinases 1 and 2 (ULK1 and ULK2) in modulating autophagy and myofiber atrophy during fasting via a microRNA-specific knockdown of these proteins in mouse skeletal muscle and using a non-specific microRNA in the contralateral muscle to allow comparisons of ULK effects within the same animal. Our results revealed that deficiency of ULK1 caused LC3-I to accumulate in fasted muscle without changes in Lc3b mRNA, indicating an impairment in the step of LC3-I conversion into LC3-II (an essential step in autophagy initiation). Similar trends were observed with other LC3-like proteins (GABL1 and GABL2) suggesting a specific role for ULK1 in regulating autophagy initiation. Deficiency of ULK2 did not affect LC3 or LC3-like proteins suggesting that ULK2 does not regulate autophagy initiation. However, it led to accumulation of ubiquitinated proteins, and the autophagy adaptors p62 and NBR-1, under both basal and fasting conditions. Since autophagy adaptors bind to and are degraded together with ubiquitinated proteins, these findings are consistent with impaired involvement of adaptors and consequent deficient cargo recognition by autophagy. Of note, deficient expression of either ULK1, ULK2, or both ULK1 & ULK2 did not attenuate myofiber atrophy during fasting. Altogether, these results uncover fundamental divergent roles for ULK1 and ULK2 in modulating autophagy and its selectivity in muscle. Current and future studies in our laboratory will further expand the molecular signature of autophagy activation and selectivity in muscle in order to identify novel targets for therapy in conditions associated with autophagy deficiency.

Strength and Conditioning for Young Athletes offers an evidence-based introduction to the theory and practice of strength and conditioning for children and young athletes. Drawing upon leading up-to-date research in all aspects of fitness and movement skill development, the book adopts a holistic approach to training centred on the concept of long-term athletic development and the welfare of the young athlete.

Aging in skeletal muscle is characterized by a loss in muscular performance. This is in part related to the direct loss of muscle mass due to senescence, known as sarcopenia. With age, skeletal muscles lose force production, contractile speed, and power production. The force velocity relationship of muscle is a product of force production and contraction speed, both of which decline with age; however, the mechanisms and trajectory of this decline are not well understood. Exercise has positive effects on muscle, and thus may assist in maintaining performance in old age. However, few long-term studies have been performed to examine the effects of life-long exercise on muscle contractile performance. In order to test the potential for life-long exercise to reduce the effects of again on muscle contractile performance, muscle performance was determined in control mice and mice selected for high voluntary wheel running at baseline, adult, and old ages. Peak isometric force declined with age in control (C) mice without exercise (P

In this dissertation, I explore the ways in which theories and concepts of face-to-face interaction and disclosure management can be used to understand the construction of privacy on an intercollegiate sport team. The purpose of this research was to examine how team members talked to each other about themselves, and how they managed the personal information shared. Erving Goffman's model of social interaction and his concepts of "face" and "supportive work" frame the analyses of this study. Through semi-structured interviews and direct observations of the members of an NCAA Division III women's basketball team, I discovered the team's rules and the development of their communication norms, which were most salient during discussions involving the players' tattoos and two unanticipated team meetings. It was important to the players of this team that they were a close-knit group who got along well and supported each other. The players questioned the commitment level of a player who disrupted the team's closeness by breaking a rule or norm and refused to make amends for her discretion. My findings suggest that the team members negotiated how to demonstrate their commitment to the team and to each other by performing supportive and remedial work through disclosure during these two meetings. Even under those specific circumstances, a player maintained some amount of autonomy by controlling the depth of her personal information that she shared. Interestingly, the players did not indicate an experienced loss of control over their personal information after they shared it with other team members at the meetings due to the team's negotiation of information boundary management. Additionally, I found that the symmetry and reciprocity of disclosure differed between player-to-player and player-to-coach interactions.

PURPOSE: To understand the influences of mechanical loading on bone adaptation, the ground reaction force (GRF) applied to the bone must be quantified. The use of force plates in a lab setting is the accepted method for quantifying GRFs; however, this is not feasible in free-living situations. Recent developments in accelerometer technology may provide the ability to evaluate the effects of mechanical loading on bone outside of laboratory settings. The purpose of this project was to validate an accelerometer for the measurement of mechanical loading by comparing its output against GRFs. METHODS: Male and female participants (n = 20 males, 20 females; 18 to 49 yr) completed 10 repetitions of 9 common everyday movements (stand, walk, jog, run, 15 cm jump, step down from curb, drop down from curb, forward hop, and side hop) on a force plate with an accelerometer worn on their right hip. Then, a subset (n = 5 males, 5 females) wore an accelerometer on their right hip and played basketball, volleyball, and dodgeball as a group. Finally, all 40 participants wore an accelerometer home for 7 days. All activities were organized into derived activity categories labeled as low-, moderate-, and high-mechanical-load-intensity and used with 59 possible accelerometer variables to predict mechanical load. Models were fit using the randomForest package in R. Model performance (coefficient of determination [R2] and median absolute error) was evaluated using cross-validation. RESULTS: The percentage of variation mechanical load intensity explained by the models ranged from 0.27 to 0.78 with median absolute errors ranging from 0.20 to 0.49. The model with R2 = 0.78 contained the known activity categories and the accelerometer variables, but this is not realistic for free-living situations where activity categories will not be known. The two free-living models with the highest R2 values included derived activity categories and accelerometer variables, and estimated, on average, 21.1 and 20.7 hours per day in low-intensity, 1.6 and 1.7 hours per day in moderate-intensity, and 0.0 and 0.5 hours per day in high-intensity osteogenic activity, respectively. CONCLUSION: It is assumed that higher intensity activities (i.e., jumping vs. jogging) result in higher GRF values, but depending on the actual execution of the movement, this is not always the case. This research demonstrated that models containing the accelerometer variables performed better in predicting GRF than those containing only the derived activity categories. This supports the hypothesis that accelerometers provide valuable objective information when evaluating mechanical loading on bone.