'WARM-UP' EFFECTS ON FREQUENCY CONTENT OF EMG IN DYNAMIC EXERCISE: IMPLICATIONS FOR ASSESSING FATIGUE

The purpose of this study was to examine the implications of the increasing muscle temperature that occurs during dynamic exercise for using the frequency content of EMG for assessing muscle fatigue in such activities. It is known that the temperature of the active muscles can be elevated to around 40°C during prolonged exhaustive exercise (Saltin et ai, 1972) and that temperature changes can affect the frequency content of surface EMG (Merletti et ai, 1984). Several of the previous studies in this area have shown initial increases in median frequency (fmed) prior to a decline with fatigue where the activity was not proceeded by other exercise (Jansen et ai, 1997, Gosselin et ai, 2000, Hausswirth et ai, 2000). It is hypothesised that these initial rises are due to increasing muscle temperature and that this may affect the accurate measurement of fatigue

A THREE-DIMENSIONAL ANALYSIS OF MALE AND FEMALE ELITE SPRINT KAYAK PADDLERS

The purpose of this study was to investigate whether there were technique differences between national level male (n=6) and female sprint kayak paddlen (n=4) to indicate whether the same coaching strategies could be used for men and women. It was found that, despite different boat velocities, male and female paddlen were not very different in some important technique variables. It was concluded that, until distinct differences are found in technique between men and women, these groups could be coached the same way

Inequalities around fashioned bodies, style, and beauty: A seminar examining social injustices related to the apparel industry, discipline, and/or personal aesthetics

The seminar was centered around scholarship related to or addressing social justice or social justice issues in the apparel industry, our discipline, or personal and/or community aesthetics and styles. We focused on work examining underrepresented populations such as: (a) people of color, (b) the LGBTQ+ community, (c) people of a variety of abilities, and/or (d) other groups that have a history of oppression, discrimination, or power and privilege inequalities. The seminar had a non-traditional “arrangement” in the room with “exhibits” of scholarly work and “mini talks” from each presenter. Our goal was to initiate and encourage these discussions to go beyond the seminar session and for the participants to engage in dialogue at their home institutions and programs while building a network of people in the seminar to dialogue about in the future

The effect of powder re-use on the coalescence behaviour and isothermal crystallisation kinetics of polyamide 12 within powder bed fusion

Polymer powder bed fusion (PBF) is becoming increasingly popular for the fabrication of lightweight, high-performance parts, particularly for medical and aerospace applications. This study investigates the effect of powder re-use and material aging on the coalescence behaviour, melt flowability, and isothermal crystallisation kinetics of polyamide-12 (PA-12) powder. With increased powder re-use, a progressive reduction in melt flowability and material coalescence is observed; at 200 °C, the particle consolidation time increases from 15 s in virgin powder to 180 s in powder recovered from build 6. The observed changes in the behaviour of PA-12 were attributed to polycondensation and cross-linking; these aging phenomena also create structural defects, which hinder the rate and extent of primary crystallisation. At an isothermal crystallisation temperature of 165 °C, the crystallisation half-time increased from 12.78 min in virgin powder to 23.95 min in powder re-used across six build cycles. As a result, the commonly used Avrami model was found to be unsuitable for modelling the crystallisation behaviour of aged PA-12 powder, with the coefficient of determination (R2) reducing from >0.995 for virgin powder to as low as 0.795 for reused powder. On the other hand, an alternative method, the Hay model, is able to successfully track full phase transformation within re-used powder (R2 >0.99). These results highlight the importance of selecting the most appropriate model for analysing the crystallisation kinetics of PA-12 powder re-used across multiple build cycles. This understanding is crucial for obtaining the strong mechanical properties and dimensional precision required for the fabrication of functional, end-use parts within PBF

Elevated O-GlcNAc levels activate epigenetically repressed genes and delay mouse ES cell differentiation without affecting naive to primed cell transition

The differentiation of mouse embryonic stem (ES) cells is controlled by the interaction of multiple signaling pathways, typically mediated by post-translational protein modifications. The addition of O-linked N-acetylglucosamine (O-GlcNAc) to serine and threonine residues of nuclear and cytoplasmic proteins is one such modification (O-GlcNAcylation), whose function in ES cells is only now beginning to be elucidated. Here we demonstrate that the specific inhibition of O-GlcNAc hydrolase (Oga) causes increased levels of protein O-GlcNAcylation and impairs differentiation of mouse ES cells both in serum-free monolayer and in embryoid bodies (EBs). Use of reporter cell lines demonstrates that Oga inhibition leads to a reduction in the number of Sox1-expressing neural progenitors generated following induction of neural differentiation, as well as maintained expression of the ES cell marker Oct4 (Pou5f1). In EBs expression of mesodermal and endodermal markers is also delayed. However, the transition of naïve cells to primed pluripotency indicated by Rex1 (Zfp42), Nanog, Esrrb and Dppa3 downregulation and Fgf5 upregulation remains unchanged. Finally, we demonstrate that increased O-GlcNAcylation results in upregulation of genes normally epigenetically silenced in ES cells, supporting the emerging role for this protein modification in the regulation of histone modifications and DNA methylation. Stem Cells 2014

Assessing The Impact of Body Fat Percentage And Lean Mass, on Wingate Performance

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Why a Universal Population-Level Approach to the Prevention of Child Abuse is Essential

This paper argues for the importance of adopting a population-level approach to promote more effective parenting and to reduce the risk of child maltreatment. Family-based interventions based on social learning principles have been shown to make a useful contribution in the treatment of child maltreatment. However, typically such programmes have been used to treat parents who have already become involved in the child protection system. We argue that the creation of community-wide support structures to support positive parenting is needed to reduce the prevalence of child maltreatment. Such an approach requires several criteria to be met. These include having knowledge about the prevalence rates for the targeted child outcomes sought, knowledge about the prevalence of various parenting and family risk factors, evidence that changing family risk factors reduces the prevalence of targeted problems, having culturally appropriate, cost-effective, evidence-based interventions available and making these widely accessible

Long-distance staple transport in western Mesoamerica: Insights through quantitative modeling

Conceptualizations of pre-Hispanic staple transport remain underdeveloped. Conventional wisdom has long maintained that while prestige goods could demand long-distance transport, staple transport was short distance. A quantitative model reveals the fallacy of that argument and establishes the possibility of long-distance, overland staple transport in Mesoamerica by using maize tribute transport between Zempoala and Tenochtitlan as an example. This conclusion has implications for understanding Mesoamerican interregional exchange, ecology, and society

ROLLING ACTIONS OF SHOULDERS AND HIPS IN FREESTYLE SWIMMING

The purpose of this study was to determine accurately the magnitude of shoulder roll (SR) and hip roll (HR) in freestyle swimming, to assess the significance of the differences between these parameters and to examine whether they are associated with swimming velocity (V). Six male swimmers of national and international level performed a maximum freestyle swim. One non-breathing stroke cycle was selected for analysis. It was shown that swimmers rolled their shoulders significantly more than their hips. Faster swimming velocities were associated with smaller magnitudes of SR, but no significant correlations were found for V and HR. These results indicated that SR and HR need to be examined separately in freestyle swimming, as the measurement of body roll for the whole trunk does not represent with validity the rolling characteristics of the trunk