• H55N polymorphism as a likely cause of variation in citrate synthase activity of mouse skeletal muscle

      Ratkevicius, Aivaras; Carroll, Andrew M.; Kilikevicius, Audrius; Venckunas, Tomas; McDermott, Kevin T.; Gray, Stuart R.; Wackerhage, Henning; Lionikas, Arimantas (American Physiological Society, 2010)
      The aim of this study was to investigate the mechanisms underlying low activity of citrate synthase (CS) in A/J mice compared with other inbred strains of mice. Enzyme activity, protein content, and mRNA levels of CS were studied in the quadriceps muscles of A/J, BALB/cByJ, C57BL/6J, C3H/HeJ, DBA/2J, and PWD/PhJ strains of mice. Cytochrome c protein content was also measured. The results of the study indicate that A/J mice have a 50–65% reduction in CS activity compared with other strains despite similar levels of Cs mRNA and lack of differences in CS and cytochrome c protein content. CS from A/J mice also showed lower Michaelis constant (Km) for both acetyl CoA and oxaloacetate compared with the other strains of mice.
    • Has yin [female] got the upper hand over yang [male]?

      Wu, Ping (Sense Publishers, Rotterdam, 2010)
    • Helping pre-service and beginning teachers examine and reframe assumptions about themselves as teachers and change agents: “who is going to listen to you anyway?”

      MacPhail, Ann; Tannehill, Deborah (Taylor and Francis, 2012)
      The focus of this article is how to ensure (beginning) teachers’ needs as practitioners are part of the discursive dialogue in physical education teacher education programs. We consider the relationship between ‘structure’ and ‘agency,’ teachers as ‘change agents’ and refer to ‘workplace learning’ as we examine the extent to which the social structure of the school and the teaching profession, and / or the capacity of the individual to act independently, ultimately determines a teacher's behaviour in reaction to teaching expectations. We are interested as physical education teacher education faculty in how we (1) strive to help pre-service teachers examine and reframe assumptions about themselves as teachers and change agents, and (2) examine taken-for-granted school practices and processes. We share ways that physical education teacher education programs could encourage pre-service teachers agency and the relationship between initial teacher education and induction.
    • Hiding behind the camera: social learning within the Cooperative Learning Model to engage girls in physical education

      Goodyear, Victoria A.; Casey, Ashley; Kirk, David (Taylor and Francis, 2012)
      Research suggests that girls are disengaged in physical education due to the ‘traditional’ way that it is taught, i.e. teacher-centred approaches with a primary focus on motor performance. In contrast, Cooperative Learning, a student-centred pedagogy focusing on learning in multiple domains, has had success in engaging girls in physical education. Furthermore, when cooperative group work has been combined with technology, student engagement with learning is heightened. This article discusses the use of Cooperative Learning and video cameras to bring about a positive change to the learning environment for girls who were identified as being disengaged in physical education.
    • The human imprintome: regulatory mechanisms, methods of ascertainment, and roles in disease susceptibility

      Skaar, David A.; Li, Yue; Bernal, Autumn J.; Hoyo, Cathrine; Murphy, Susan K.; Jirtle, Randy L. (National Academy of Sciences, 2012-12)
      Imprinted genes form a special subset of the genome, exhibiting monoallelic expression in a parent-of-origin-dependent fashion. This monoallelic expression is controlled by parental-specific epigenetic marks, which are established in gametogenesis and early embryonic development and are persistent in all somatic cells throughout life. We define this specific set of cis-acting epigenetic regulatory elements as the imprintome, a distinct and specially tasked subset of the epigenome. Imprintome elements contain DNA methylation and histone modifications that regulate monoallelic expression by affecting promoter accessibility, chromatin structure, and chromatin configuration. Understanding their regulation is critical because a significant proportion of human imprinted genes are implicated in complex diseases. Significant species variation in the repertoire of imprinted genes and their epigenetic regulation, however, will not allow model organisms solely to be used for this crucial purpose. Ultimately, only the human will suffice to accurately define the human imprintome.
    • The hypertriglyceridemic waist, waist-to-height ratio, and cardiometabolic risk

      Bailey, Daniel Paul; Savory, Louise A.; Denton, Sarah J.; Davies, Ben Rhys; Kerr, Catherine J. (Elsevier, 2013)
      The aim of the study was to investigate whether the hypertriglyceridemic waist (HW) phenotype and waist-to-height ratio (WHTR) are associated with cardiometabolic disorders in children and adolescents.
    • Hypoxia mediated release of endothelial microparticles and increased association of S100A12 with circulating neutrophils

      Vince, Rebecca V.; Chrismas, Bryna C.; Midgley, Adrian W.; McNaughton, Lars R.; Madden, Leigh A. (Hindawi Publishing Corporation, 2009)
      Microparticles are released from the endothelium under normal homeostatic conditions and have been shown elevated in disease states, most notably those characterised by endothelial dysfunction. The endothelium is sensitive to oxidative stress/status and vascular cell adhesion molecule-1 (VCAM-1) expression is upregulated upon activated endothelium, furthermore the presence of VCAM-1 on microparticles is known. S100A12, a calcium binding protein part of the S100 family, is shown to be present on circulating leukocytes and is thought a sensitive marker to local inflammatory process, which may be driven by oxidative stress. Eight healthy males were subjected to breathing hypoxic air (15% O(2), approximately equivalent to 3000 metres altitude) for 80 minutes in a temperature controlled laboratory and venous blood samples were processed immediately for VCAM-1 microparticles (VCAM-1 MP) and S100A12 association with leukocytes by flow cytometry. A pre-hypoxic blood sample was used for comparison. Both VCAM-1 MP and S100A12 association with neutrophils were significantly elevated post hypoxic breathing later declining to levels observed in the pre-test samples. A similar trend was observed in both cases and a correlation may exist between these two markers in response to hypoxia. These data offer evidence using novel markers of endothelial and circulating blood responses to hypoxia.
    • Hypoxia-mediated prior induction of monocyte-expressed HSP72 and HSP32 provides protection to the disturbances to redox balance associated with human sub-maximal aerobic exercise.

      Taylor, Lee; Hillman, Angela R.; Midgley, Adrian W.; Peart, Daniel J.; Chrismas, Bryna C.; McNaughton, Lars R.; University of Bedfordshire (2012-03-23)
      HSP72 is rapidly expressed in response to a variety of stressors in vitro and in vivo (including hypoxia). This project sought a hypoxic stimulus to elicit increases in HSP72 and HSP32 in attempts to confer protection to the sub-maximal aerobic exercise-induced disturbances to redox balance. Eight healthy recreationally active male subjects were exposed to five consecutive days of once-daily hypoxia (2,980 m, 75 min). Seven days prior to the hypoxic acclimation period, subjects performed 60 min of cycling on a cycle ergometer (exercise bout 1-EXB1), and this exercise bout was repeated 1 day post-cessation of the hypoxic period (exercise bout 2-EXB2). Blood samples were taken immediately pre- and post-exercise and 1, 4 and 8 h post-exercise for HSP72 and immediately pre, post and 1 h post-exercise for HSP32, TBARS and glutathione [reduced (GSH), oxidised (GSSG) and total (TGSH)], with additional blood samples obtained immediately pre-day 1 and post-day 5 of the hypoxic acclimation period for the same indices. Monocyte-expressed HSP32 and HSP72 were analysed by flow cytometry, with measures of oxidative stress accessed by commercially available kits. There were significant increases in HSP72 (P < 0.001), HSP32 (P = 0.03), GSSG (t = 9.5, P < 0.001) and TBARS (t = 5.6, P = 0.001) in response to the 5-day hypoxic intervention, whereas no significant changes were observed for GSH (P = 0.22) and TGSH (P = 0.25). Exercise-induced significant increases in HSP72 (P < 0.001) and HSP32 (P = 0.003) post-exercise in EXB1; this response was absent for HSP72 (P ≥ 0.79) and HSP32 (P ≥ 0.99) post-EXB2. The hypoxia-mediated increased bio-available HSP32 and HSP72 and favourable alterations in glutathione redox, prior to exercise commencing in EXB2 compared to EXB1, may acquiesce the disturbances to redox balance encountered during the second physiologically identical exercise bout.
    • Identification of non-specific tactical tasks in invasion games

      Memmert, Daniel; Harvey, Stephen (2012-05-23)
    • Identity work: young disabled people, family and sport

      Fitzgerald, Hayley; Kirk, David; Leeds Metropolitan University; University of Bedfordshire (Routledge, 2009-09)
      It has long been recognised that family is an important arena in which sporting tastes and interests are nurtured. Indeed, for many young people the family introduces them to and then provides ongoing support for engaging in sport. Research has also indicated that the family has a significant position in the lives of young disabled people. In this paper we explore the interrelationships between sport, family and disability. Like a number of writers within disability studies we see the benefits of moving beyond a structure/agency dichotomy that currently limits social and medical model understandings of disability. In particular, we draw on the work of Marcel Mauss and Pierre Bourdieu both of whom argued that social life can be better understood by considering the embodiment of individuals through their habitus. We draw on data generated in an interview-based study with 10 young disabled people to explore the ways in which family contributes to, and mediates, sporting tastes and interests. We consider two key questions: How do young disabled people negotiate relations within the family and in what ways do these relations influence sporting tastes and interests? To what extent are young disabled people able to use sport to generate and convert (valued) capital within the family and other related arenas?
    • The implementation of models-based practice in physical education through action research

      Casey, Ashley; Dyson, Ben (2012-05-15)
      The purpose of this study was to explore the use of action research as a framework to investigate cooperative learning and tactical games as instructional models in physical education (PE). The teacher/researcher taught a tennis unit using a combination of Cooperative Learning and Teaching Games for Understanding to three classes of boys aged 11—12. Data collection included: teacher and pupil evaluations of skill, pupil reflections on the lessons, pupil interviews, teacher field journal and the documentation and course materials from the unit of work. Data analysis was conducted using inductive analysis and constant comparison (Denzin and Lincoln, 1994; Lincoln and Guba, 1985). The results of this research reinforce the concept that the implementation of any new pedagogical approach is time-consuming and highly labour intensive (Fullan, 1999). The conceptual shift the teacher/researcher made to relinquish control to students was one of the most difficult, but important, outcomes of this action research process.
    • Instructional climates in preschool children who are at-risk. Part I: object-control skill development

      Robinson, Leah E.; Goodway, Jacqueline D. (American Alliance for Health, Physical Education, Recreation & Dance, 2009-09)
      Part I of this study examined the effect of two 9-week instructional climates (low autonomy [LA] and mastery motivational climate [MMC]) on object-control (OC) skill development in preschoolers (N = 117).
    • Intermittent exercise with and without hypoxia improves insulin sensitivity in individuals with type 2 diabetes

      Mackenzie, Richard W.; Maxwell, Neil S.; Castle, Paul C.; Elliott, B.; Brickley, Gary; Watt, Peter; University of Westminster (2012-04)
      Hypoxia and muscle contraction stimulate glucose transport activity in vitro. Exercise and hypoxia have additive effects on insulin sensitivity in type 2 diabetics (T2D).
    • An investigation into the effect of a pre-performance strategy on jump performance

      Fletcher, Iain M. (Lippincott, Williams & Wilkins, 2013)
      The aim of this study was to explore the effect that different components, making up a commonly used pre-performance preparation strategy, have on jump height performance. Sixteen male collegiate athletes (age, 21.38 ± 0.52 years; height, 1.79 ± 0.07 m; and body mass, 75.1 ± 5.26 kg) performed a preparation strategy involving a cycle ergometer warm-up, followed by a dynamic stretch component, and finishing with heavy back squats. This intervention was repeated to test countermovement, squat or drop jump performance after each component of the preparation strategy, with electromyographic activity measured during each jump test. Significant increases (p < 0.05) in jump height and electromyographic activity were noted, with a stepwise increase in performance from pre- to post-warm-up, increased further by the dynamic stretch component and again increased after the back squat.
    • An investigation into the effects of different warm-up modalities on specific motor skills related to soccer performance.

      Fletcher, Iain M.; Monte-Colombo, Mathew M.; University of Bedfordshire (2010-08)
      The aim of this study was to investigate the effect of different warm-up stretch modalities on specific high-speed motor capabilities important to soccer performance. Twenty-seven male soccer players performed 3 warm-up conditions, active warm-up (WU), WU with static stretching (SPS), and WU with dynamic stretching (ADS). Heart rate, countermovement jump, 20-m sprint, and Balsom agility tests were performed after each intervention. Vertical jump heights were significantly greater (p < 0.01) in the WU and ADS conditions compared to those in the SPS trial. The 20-m sprint and agility times showed that the SPS condition was significantly slower (p < 0.01) than the WU and ADS conditions, with the ADS trial being significantly faster (p < 0.05) than the WU condition. Heart rate was significantly higher (p < 0.01) for participants post-WU and -ADS trials compared to the SPS condition. These findings suggest that the superior performance of the dynamic stretch and warm-up-only conditions compared to the static stretch condition may be linked to increases in heart rate. The reasons for the dynamic stretch trial superiority compared to the warm-up condition are less clear and as yet to be established. We recommend for optimal performance, specific dynamic stretches be employed as part of a warm-up, rather than the traditional static stretches.
    • An investigation into the possible physiological mechanisms associated with changes in performance related to acute responses to different preactivity stretch modalities.

      Fletcher, Iain M.; Monte-Colombo, Mathew M.; University of Bedfordshire (2010-02)
      The aim of this study was to explore the potential mechanisms underlying performance changes linked to different warm-up stretch modalities. Twenty-one male collegiate-semiprofessional soccer players (age, 20.8 +/- 2.3 years) performed under 3 different warm-up conditions: a no-stretch warm-up (WU), a warm-up including static passive stretches (SPS), and a warm-up incorporating static dynamic stretches (SDS). Countermovement jump, drop jump, peak torque, heart rate, core temperature, movement kinematics, and electromyography (EMG) were recorded for each intervention. Significant increases (p < 0.001) in performance were recorded for the countermovement, drop jump, and peak torque measures when the SDS was compared with the WU and SPS trials. When mechanism data were analysed, heart rate was significantly higher (p < 0.001) in the SDS condition compared with the SPS and WU conditions (a pattern also shown with core temperature), whereas the WU condition heart rate was also significantly higher than the SPS condition heart rate. When EMG data were examined for the rectus femoris muscle, significantly greater (p < 0.01) muscle activity was observed in the SDS condition compared with the SPS condition. It seems the most likely mechanisms to explain the increase in performance in the SDS condition compared with the SPS condition are increased heart rate, greater muscle activity, and increased peak torque.
    • Junior sport as a moral practice

      Kirk, David; Loughborough University (Human Kinetics, 2002-07)
      Critiques Siedentop's keynote address, "Junior Sport and the Evolution of Sport Cultures," reviewing and rationalizing Siedentop's four goals for junior sport (educative, public health, elite development, and preserving, protecting, and enhancing specific sport practices), discussing Siedentop's views on sport as a collective cultural and moral practice, and explaining the salience of Siedentop's views today and in the future.
    • Junior sport models representing best practice nationally and internationally.

      Kirk, David; Brettschneider, W.; Auld, C. (Canberra: Australian Sports Commission, 2007)
    • Just how happy is the happy puppet? An emotion signaling and kinship theory perspective on the behavioral phenotype of children with Angelman syndrome.

      Brown, William Michael; Consedine, Nathan S.; Long Island University (2004)
      The favored level of parental investment in a child may differ for genes of maternal and paternal origin in the child. This conflict can be expressed in the phenomenon of genomic imprinting that refers to situations in which the same gene is differentially expressed depending on its parent of origin. Two disorders that show the effects of genomic imprinting--both at 15q11-q13--are Angelman Syndrome (AS) which is due to the absence of expression of maternally-inherited genes and Prader-Willi syndromes (PWS) which is due to the absence of expression of paternally-inherited genes. However, although both disorders can arise from the deletion of the same genetic region, the gustatory, behavioral, and affective characteristics of AS and PWS children are remarkably distinct. Recent research inspired by kinship theory has suggested the origins of these phenotypic differences may lie in the differential investment of each parent's genome in the AS or PWS child. Specifically, it is thought that each set of parental genes have different 'ideas' regarding how the child should behave towards the mother and how much investment they should look to extract. In normal cases, the trade-off between the competing parental genomes produces a behavioral equilibrium in the child. However, in pathological instances, particularly where gene expression is one-sided, the evolved behavioral strategies favored by the contributing genome will dominate the child's behavior. To date, research in the area of genomic conflict in AS and PWS children has primarily focusing on differences in post-natal nutrition-related behaviors. The current paper extends this framework by offering an emotion and evolutionary signaling interpretation of the affective characteristics of AS children. A review of the affective characteristics of the two syndromes (PWS and AS) is presented before kinship and emotions theory are used to examine the functions that differential affect expression may serve in altering maternal investment. We expected that because the ultimate goal of paternal genes is to increase the child rearing burden of mothers, the Angelman behavioral phenotype should exhibit the emotion signaling characteristics that elicit levels of investment more consistent with paternal genetic interests. AS children display more positive, relative to negative, affect expressions (i.e. AS children laugh and smile more frequently than PWS children). In affect signaling theories, positive affect signals (i.e., smiling, laughing) have evolved to manipulate the sensory systems of receivers to increase social resources. In contrast, because the expression of some negative affects may indicate to the mother that the infant is not viable, negative affect expression is characteristically low among AS children. However, AS children may nonetheless have high levels of non-expressed anxiety because of its role in assisting the child (and its paternal genome) to maintain vigilance for changes in investment on the part of the mother. Overall, our kinship and emotion signaling analysis of AS children suggests that their global pattern of affect signaling represents one manifestation of an array of possible evolved strategies within the parental genome. Specifically, because AS exhibits the effects of paternally-inherited genes unhindered by the expression of maternally-inherited genes, the AS infant manifests a pattern of expression and non-expression that maximize maternal investment and thus paternal fitness. This theory is a significant departure from the standard but erroneous conjecture that a mother and child's inclusive fitness interests are one and the same.