• Breaking up prolonged sitting time with walking does not affect appetite or gut hormone concentrations but does induce an energy deficit and suppresses postprandial glycaemia in sedentary adults

      Bailey, Daniel Paul; Broom, David R.; Chrismas, Bryna C.; Taylor, Lee; Flynn, Edward; Hough, John (NRC Research Press, 2015-12-14)
      Background: Breaking up periods of prolonged sitting can negate harmful metabolic effects but the influence on appetite and gut hormones is not understood and is investigated in this study. Methods: Thirteen sedentary (7 female) participants undertook three, 5 h trials in random order: 1) uninterrupted sitting (SIT), 2) seated with 2 min bouts of light-intensity walking every 20 min (SIT+LA), and 3) seated with 2 min bouts of moderate-intensity walking every 20 min (SIT+MA). A standardised test drink was provided at the start and an ad libitum pasta test meal provided at the end of each trial. Subjective appetite ratings and plasma acylated ghrelin, peptide YY, insulin, and glucose were measured at regular intervals. Area under the curve (AUC) was calculated for each variable. Results: AUC values for appetite and gut hormone concentrations were unaffected in the activity breaks conditions compared to uninterrupted sitting (linear mixed modelling: p>0.05). Glucose AUC was lower in SIT+MA than SIT+LA (p=0.004) and SIT (p=0.055). There was no difference in absolute ad libitum energy intake between conditions (p>0.05), however, relative energy intake was lower in SIT+LA (39%; p=0.011) and SIT+MA (120%; p<0.001) than SIT. Conclusion: Breaking up prolonged sitting does not alter appetite and gut hormone responses to a meal over a 5 h period. Increased energy expenditure from activity breaks could promote an energy deficit that is not compensated for in a subsequent meal.
    • Appetite and gut hormone responses to moderate-intensity continuous exercise versus high-intensity interval exercise, in normoxic and hypoxic conditions

      Bailey, Daniel Paul; Smith, Lindsey Rachel; Chrismas, Bryna C.; Taylor, Lee; Stensel, David J.; Deighton, Kevin; Douglas, Jessica A.; Kerr, Catherine J.; University of Bedfordshire; Oxford Brookes University; et al. (Elsevier, 2015-06)
      This study investigated the effects of continuous moderate-intensity exercise (MIE) and high-intensity interval exercise (HIIE) in combination with short exposure to hypoxia on appetite and plasma concentrations of acylated ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Twelve healthy males completed four, 2.6 h trials in a random order: (1) MIE-normoxia, (2) MIE-hypoxia, (3) HIIE-normoxia, and (4) HIIE-hypoxia. Exercise took place in an environmental chamber. During MIE, participants ran for 50 min at 70% of altitude-specific maximal oxygen uptake (View the MathML sourceV˙O2max) and during HIIE performed 6 × 3 min running at 90% View the MathML sourceV˙O2max interspersed with 6 × 3 min active recovery at 50% View the MathML sourceV˙O2max with a 7 min warm-up and cool-down at 70% View the MathML sourceV˙O2max (50 min total). In hypoxic trials, exercise was performed at a simulated altitude of 2980 m (14.5% O2). Exercise was completed after a standardised breakfast. A second meal standardised to 30% of participants' daily energy requirements was provided 45 min after exercise. Appetite was suppressed more in hypoxia than normoxia during exercise, post-exercise, and for the full 2.6 h trial period (linear mixed modelling, p < 0.05). Plasma acylated ghrelin concentrations were lower in hypoxia than normoxia post-exercise and for the full 2.6 h trial period (p < 0.05). PYY concentrations were higher in HIIE than MIE under hypoxic conditions during exercise (p = 0.042). No differences in GLP-1 were observed between conditions (p > 0.05). These findings demonstrate that short exposure to hypoxia causes suppressions in appetite and plasma acylated ghrelin concentrations. Furthermore, appetite responses to exercise do not appear to be influenced by exercise modality.
    • Breaking up prolonged sitting with light-intensity walking improves postprandial glycemia, but breaking up sitting with standing does not

      Bailey, Daniel Paul; Locke, Christopher D.; University of Bedfordshire (Elsevier, 2015-05)
      Objectives: To explore the effects of breaking up prolonged sitting time with standing or light-intensity walking on a range of cardiometabolic risk markers. Design: A randomised three-period, three-treatment acute crossover trial. Methods: Ten non-obese adults took part in three trials: (1) uninterrupted sitting; (2) seated with 2-min bouts of standing every 20 min; and (3) seated with 2-min bouts of light-intensity walking every 20 min. Two standardised test drinks (total 80.3 carbohydrate, 50 g fat) were provided after an initial 1-h period of uninterrupted sitting. Plasma glucose and blood pressure were assessed hourly to calculate area under the curve. Total cholesterol, HDL, and triglycerides were assessed at baseline and 5-h. ANOVAs were used to explore between-trial differences. Results: Glucose area under the curve was lower in the activity-break condition compared to the uninterrupted sitting and standing-break conditions: mean area under the curve 18.5 (95% CI 17, 20), 22.0 (20.5, 23.5), and 22.2 (20.7, 23.7) mmol L/5-h, respectively, p < 0.001; no difference between uninterrupted sitting and standing-break conditions (p > 0.05). Systolic and diastolic blood pressure area under the curve did not differ significantly between conditions, nor did responses in lipid parameters (p > 0.05). Conclusions: This study suggests that interrupting sitting time with frequent brief bouts of light-intensity activity, but not standing, imparts beneficial postprandial responses that may enhance cardiometabolic health. These findings may have importance in the design of effective interventions to reduce cardiometabolic disease risk.
    • Exercise-associated DNA methylation change in skeletal muscle and the importance of imprinted genes: a bioinformatics meta-analysis

      Brown, William Michael; University of Bedfordshire (BMJ Publishing Group Limited, 2015-03-30)
      BACKGROUND: Epigenetics is the study of processes-beyond DNA sequence alteration-producing heritable characteristics. For example, DNA methylation modifies gene expression without altering the nucleotide sequence. A well-studied DNA methylation-based phenomenon is genomic imprinting (ie, genotype-independent parent-of-origin effects). OBJECTIVE: We aimed to elucidate: (1) the effect of exercise on DNA methylation and (2) the role of imprinted genes in skeletal muscle gene networks (ie, gene group functional profiling analyses). DESIGN: Gene ontology (ie, gene product elucidation)/meta-analysis. DATA SOURCES: 26 skeletal muscle and 86 imprinted genes were subjected to g:Profiler ontology analysis. Meta-analysis assessed exercise-associated DNA methylation change. DATA EXTRACTION: g:Profiler found four muscle gene networks with imprinted loci. Meta-analysis identified 16 articles (387 genes/1580 individuals) associated with exercise. Age, method, sample size, sex and tissue variation could elevate effect size bias. DATA SYNTHESIS: Only skeletal muscle gene networks including imprinted genes were reported. Exercise-associated effect sizes were calculated by gene. Age, method, sample size, sex and tissue variation were moderators. RESULTS: Six imprinted loci (RB1, MEG3, UBE3A, PLAGL1, SGCE, INS) were important for muscle gene networks, while meta-analysis uncovered five exercise-associated imprinted loci (KCNQ1, MEG3, GRB10, L3MBTL1, PLAGL1). DNA methylation decreased with exercise (60% of loci). Exercise-associated DNA methylation change was stronger among older people (ie, age accounted for 30% of the variation). Among older people, genes exhibiting DNA methylation decreases were part of a microRNA-regulated gene network functioning to suppress cancer. CONCLUSIONS: Imprinted genes were identified in skeletal muscle gene networks and exercise-associated DNA methylation change. Exercise-associated DNA methylation modification could rewind the 'epigenetic clock' as we age. TRIAL REGISTRATION NUMBER: CRD42014009800.
    • The association between cardiorespiratory fitness and cardiometabolic risk in children is mediated by abdominal adiposity: the HAPPY study

      Bailey, Daniel Paul; Savory, Louise A.; Denton, Sarah J.; Kerr, Catherine J.; University of Bedfordshire; Newcastle University; Oxford Brookes University (Human Kinetics, 2014-10-13)
      Background: It is unclear whether cardiorespiratory fitness (CRF) is independently linked to cardiometabolic risk in children. This study investigated a) the association between CRF level and presence of cardiometabolic risk disorders using health-related cut points, and b) whether these associations were mediated by abdominal adiposity in children. Methods: This was a cross-sectional design study. Anthropometry, biochemical parameters and CRF were assessed in 147 schoolchildren (75 girls) aged 10-14 years. CRF was determined using a maximal cycle ergometer test. Children were classified as ‘fit’ or ‘unfit’ according to published thresholds. Logistic regression was used to investigate the odds of having individual and clustered cardiometabolic risk factors according to CRF level and whether abdominal adiposity mediated these associations. Results: Children classified as unfit had increased odds of presenting individual and clustered cardiometabolic risk factors (p < 0.05), but these associations no longer remained after adjusting for abdominal adiposity (p > 0.05). Conclusions: This study suggests that the association between CRF and cardiometabolic risk is mediated by abdominal adiposity in 10-14 year-old children and that abdominal adiposity may be a more important determinant of adverse cardiometabolic health in this age group.
    • The triglyceride to high-density lipoprotein ratio identifies children who may be at risk of developing cardiometabolic disease

      Bailey, Daniel Paul; Savory, Louise A.; Denton, Sarah J.; Davies, Ben Rhys; Kerr, Catherine J.; University of Bedfordshire; Newcastle University; Oxford Brookes University; University of Bedfordshire; Newcastle University; et al. (Wiley, 2014-08)
      Aim: It is important to develop simple, reliable methods to identify high-risk individuals who may benefit from intervention. This study investigated the association between the triglyceride to high-density lipoprotein cholesterol (TG/HDL) ratio and cardiometabolic risk, cardiorespiratory fitness and physical activity in children. Methods: Anthropometric, biochemical parameters, cardiorespiratory fitness and accelerometry determined physical activity were assessed in 155 children (80 girls) from 10 to 14 years of age from Bedfordshire, UK. Participants were grouped into high and low TG/HDL ratio groups, according to published thresholds. MANCOVA and logistic regression were used in the analysis. Results: Cardiometabolic risk factor levels were significantly higher in participants with a high TG/HDL ratio (p < 0.05). The odds of having high waist circumference (OR = 13.99; 95% CI 2.93, 69.25), elevated systolic blood pressure (5.27; 1.39, 20.01), high non-HDL cholesterol (19.47; 4.42, 85.81) and ≥2 cardiometabolic risk factors (15.32; 3.10, 75.79) were higher in participants with a high TG/HDL ratio. The TG/HDL ratio values were significantly lower in those with high cardiorespiratory fitness (p = 0.01), but there was no association with physical activity. Conclusion: These findings support the use of the TG/HDL ratio to identify children with cardiometabolic risk factors who may be at risk of developing cardiometabolic disease.
    • An elevation of resting metabolic rate with declining health in nonagenarians may be associated with decreased muscle mass and function in women and men, respectively.

      Kim, Sangkyu; Welsh, David A.; Ravussin, Eric; Welsch, Michael A.; Cherry, Katie E.; Myers, Leann; Jazwinski, S. Michal; Tulane University Health Sciences Center; Louisiana State University Health Sciences Center; Pennington Biomedical Research Center; et al. (Oxford University Press, 2014-06)
      Previously, we showed that FI34, a frailty index based on 34 health and function ability variables, is heritable and a reliable phenotypic indicator of healthy aging. We have now examined the relationship between major components of energy expenditure and the FI34 in participants of the Louisiana Healthy Aging Study. Resting metabolic rate was associated with FI34, even after adjustment for fat-free mass, fat mass, age, sex, thyroid hormones, and insulin-like growth factor 1 levels, in multiple regression analyses. In contrast, there was no association between total daily energy expenditure and FI34. Circulating creatine phosphokinase, a clinical marker of muscle damage, was also significantly associated with FI34. However, these associations of resting metabolic rate with FI34 were restricted to the oldest old (≥90 years) and absent in younger age groups. In oldest old men, the association of FI34 with creatine phosphokinase persisted, whereas in the oldest old women, only the association with resting metabolic rate pertained with the appearance of an effect of body size and composition. These results point toward an increasing metabolic burden for the maintenance of homeodynamics as health declines in nonagenarians, and this has implications for contraction of metabolic reserve that may potentially accelerate the path to disability.
    • Educational value and models-based practice in physical education

      Kirk, David; University of Bedfordshire; University of Queensland (Routledge, 2013-04-19)
      A models-based approach has been advocated as a means of overcoming the serious limitations of the traditional approach to physical education. One of the difficulties with this approach is that physical educators have sought to use it to achieve diverse and sometimes competing educational benefits, and these wide-ranging aspirations are rarely if ever achieved. Models-based practice offers a possible resolution to these problems by limiting the range of learning outcomes, subject matter and teaching strategies appropriate to each pedagogical model and thus the arguments that can be used for educational value. In this article, two examples are provided to support a case for educational value. This case is built on an examination of one established pedagogical model, Sport Education, which is informed by a perspective on ethics. Next, I consider Physical Literacy which, I suggest, is an existentialist philosophical perspective that could form the basis of a new pedagogical model. It is argued, in conclusion, that a models-based approach along with a reconstructed notion of educational value may offer a possible future for physical education that is well grounded in various philosophical arguments and the means to facilitate a wide range of diverse individual and social educational ‘goods’.
    • Physical education teachers' use of practitioner inquiry: effective, enjoyable and relevant professional learning

      Goodyear, Victoria A.; Casey, Ashley; Kirk, David (Taylor and Francis, 2013)
      The purpose of this paper is to explore how four physical education teachers in the United Kingdom engaged with reflection and dialogue as part of their daily practice. Technology, in the form of a voice recorder and focussed questions for reflection, facilitated teachers' engagement and constructive reflection. Furthermore, teachers made time within the busy school day to informally discuss their pedagogical decisions with colleagues and formally listen to their students' perceptions of their practice. Consequently, the quality of teaching in a physical education department was enhanced and practitioner inquiry supported effective, enjoyable and relevant professional learning.
    • ‘Seeing the trees not just the wood’: steps and not just journeys in teacher action research

      Casey, Ashley (Taylor and Francis, 2013)
      Employing a number of data-gathering tools (reflective journals, unit diaries, post-cycle reflective analyses, student interviews and observations) this paper examines the residual and emergent effects of cooperative learning on the participants in a second, sequential unit of track and field athletics taught a year after the first intervention. It suggests that learning was both academic and social, and that participants felt the unit built on their prior learning about track and field because it was progressive, motivational and student-centred. The paper concludes by suggesting that, in seeking to understand a teacher’s pedagogical and curricular change process, we need to intersperse research that focuses on the journey towards change with research that explores the individual processes of change.
    • The effect of isokinetic testing speed on the reliability of muscle fatigue indicators during a hip abductor-adductor fatigue protocol

      Gautrey, Charlotte N.; Watson, T.; Mitchell, Andrew C.S. (Thieme Publishing, 2013)
      The aim of this study was to investigate the reliability of fatigue indicators calculated from peak torque and total work during isokinetic speeds of 60, 90, 120 and 180° · s-1 during a hip fatigue protocol.
    • The effect of velocity on load range during isokinetic hip abduction and adduction exercise

      Gautrey, Charlotte N.; Watson, T.; Mitchell, Andrew C.S. (Thieme Publishing, 2013)
      The purpose of this study was to quantify the components of acceleration, load range and deceleration through a velocity spectrum during concentric hip abduction and adduction isokinetic exercise, and to investigate the effect of load range on peak torque and work done.
    • Foot structure and muscle reaction time to a simulated ankle sprain

      Denyer, Joanna R.; Hewitt, Naomi L. A.; Mitchell, Andrew C.S. (The National Athletic Trainers' Association, 2013)
      The study was to determine whether pronated or supinated foot structures contribute to neuromuscular deficits as measured by muscle reaction time to a simulated ankle-sprain mechanism. Conclusions: Foot structure influenced peroneus longus reaction time. Further research is required to establish the consequences of slower peroneal reaction times in pronated and supinated foot structures. Researchers investigating lower limb muscle reaction time should control for foot structure because it may influence results.
    • 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.
    • A multi-ingredient nutritional supplement increases fat oxidation and augments metabolic rate

      Saini, Amarjit; McBride, Roisin; Davies, Ben Rhys; Martin, Neil Richard William; Sculthorpe, Nicholas; Brewer, John (SciTechnol, 2013)
      The study investigated the impact of a multi-ingredient nutritional supplement (MINS) on resting metabolic rate and energy expenditure. The supplement contained a combination of factors that are normally administered in isolation (32 g protein, 8.4 g CHO, 1.7 g fibre, 105 mg caffeine and 21 mg green tea extract with 10.5 mg catechins, per 50 g serving. 18 subjects participated in the study (10 males, 8 females), mean age 21.8 yrs. Following overnight fasting, subjects ingested either MINS or an isocaloric maltodextrin placebo. Resting oxygen uptake was determined by gas analysis measuring VCO2 produced and VO2 consumed. 7 days later, the protocol was repeated using a randomised twotreatment crossover design so each individual subject’s response to both placebo and supplement was assessed. Results showed mean resting Respiratory Exchange Ratios were 0.77 ± 0.03 after supplementation, compared with 0.93 ± 0.03 after placebo (P<0.05), indicating a shift in contribution of fat to metabolism from 24 ± 2.5% (Control) to 79 ± 1.9% (MINS). Mean resting metabolic rate was found to be 3.69 ml per kg.min-1 O2 after supplementation, compared with 3.45 ml per kg.min-1 O2 after placebo. Whilst this difference is not statistically significant, it impacts on the absolute amount of fat metabolised at rest, increasing from 0.3 kcal.min-1 (Control) to 1.0 kcal.min-1 (MINS) (P<0.05). These findings may have significant implications for individuals involved in weight loss or weight management programmes.
    • Cardiorespiratory fitness is associated with hard and light intensity physical activity but not time spent sedentary in 10–14 year old schoolchildren: the HAPPY study

      Denton, Sarah J.; Trenell, Michael I.; Plötz, Thomas; Savory, Louise A.; Bailey, Daniel Paul; Kerr, Catherine J.; Broyles, Stephanie T. (Public Library of Science, 2013)
      Sedentary behaviour is a major risk factor for developing chronic diseases and is associated with low cardiorespiratory fitness in adults. It remains unclear how sedentary behaviour and different physical activity subcomponents are related to cardiorespiratory fitness in children. The purpose of this study was to assess how sedentary behaviour and different physical activity subcomponents are associated with 10–14 year-old schoolchildren's cardiorespiratory fitness.
    • Choice of activity-intensity classification thresholds impacts upon accelerometer-assessed physical activity-health relationships in children

      Bailey, Daniel Paul; Boddy, Lynne M.; Savory, Louise A.; Denton, Sarah J.; Kerr, Catherine J.; Earnest, Conrad P. (Public Library of Science, 2013)
      It is unknown whether using different published thresholds (PTs) for classifying physical activity (PA) impacts upon activity-health relationships. This study explored whether relationships between PA (sedentary [SED], light PA [LPA], moderate PA [MPA], moderate-to-vigorous PA, vigorous PA [VPA]) and health markers differed in children when classified using three different PTs.
    • Paternal obesity is associated with IGF2 hypomethylation in newborns: results from a Newborn Epigenetics Study (NEST) cohort

      Soubry, Adelheid; Schildkraut, Joellen M.; Murtha, Amy; Wang, Frances; Huang, Zhiqing; Bernal, Autumn J.; Kurtzberg, Joanne; Jirtle, Randy L.; Murphy, Susan K.; Hoyo, Cathrine; et al. (BioMed Central, 2013)
      Data from epidemiological and animal model studies suggest that nutrition during pregnancy may affect the health status of subsequent generations. These transgenerational effects are now being explained by disruptions at the level of the epigenetic machinery. Besides in vitro environmental exposures, the possible impact on the reprogramming of methylation profiles at imprinted genes at a much earlier time point, such as during spermatogenesis or oogenesis, has not previously been considered. In this study, our aim was to determine associations between preconceptional obesity and DNA methylation profiles in the offspring, particularly at the differentially methylated regions (DMRs) of the imprinted Insulin-like Growth Factor 2 (IGF2) gene.
    • 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.