• Effects of exercise intensity on salivary antimicrobial proteins and markers of stress in active men

      Allgrove, Judith E.; Gomes, Elisa; Hough, John; Gleeson, Michael; Loughborough University (Taylor & Francis, 2008-04)
      In the present study, we assessed the effects of exercise intensity on salivary immunoglobulin A (s-IgA) and salivary lysozyme (s-Lys) and examined how these responses were associated with salivary markers of adrenal activation. Using a randomized design, 10 healthy active men participated in three experimental cycling trials: 50% maximal oxygen uptake ([Vdot]O2max), 75%[Vdot]O2max, and an incremental test to exhaustion. The durations of the trials were the same as for a preliminary incremental test to exhaustion (22.3 min, s x = 0.8). Timed, unstimulated saliva samples were collected before exercise, immediately after exercise, and 1 h after exercise. In the incremental exhaustion trial, the secretion rates of both s-IgA and s-Lys were increased. An increase in s-Lys secretion rate was also observed at 75%[Vdot]O2max. No significant changes in saliva flow rate were observed in any trial. Cycling at 75%[Vdot]O2max and to exhaustion increased the secretion of α-amylase and chromogranin A immediately after exercise; higher cortisol values at 75%[Vdot]O2max and in the incremental exhaustion trial compared with 50%[Vdot]O2max were observed 1 h immediately after exercise only. These findings suggest that short-duration, high-intensity exercise increases the secretion rate of s-IgA and s-Lys despite no change in the saliva flow rate. These effects appear to be associated with changes in sympathetic activity and not the hypothalamic – pituitary – adrenal axis.
    • Effects of handgrip training with venous restriction on brachial artery vasodilation

      Credeur, Daniel P.; Hollis, Brandon C.; Welsch, Michael A.; Louisiana State University (Wolters Kluwer/ Lippincott Williams & Wilkins, 2010-07)
      Previous studies have shown that resistance training with restricted venous blood flow (Kaatsu) results in significant strength gains and muscle hypertrophy. However, few studies have examined the concurrent vascular responses following restrictive venous blood flow training protocols.
    • The effects of precompetition massage on the kinematic parameters of 20-m sprint performance

      Fletcher, Iain M.; University of Bedfordshire (2010-05)
      The purpose of this study was to investigate what effect precompetition massage has on short-term sprint performance. Twenty male collegiate games players, with a minimum training/playing background of 3 sessions per week, were assigned to a randomized, counter-balanced, repeated-measures designed experiment used to analyze 20-m sprints performance. Three discrete warm-up modalities, consisting of precompetition massage, a traditional warm-up, and a precompetition massage combined with a traditional warm-up were used. Massage consisted of fast, superficial techniques designed to stimulate the main muscle groups associated with sprint running. Twenty-meter sprint performance and core temperature were assessed post warm-up interventions. Kinematic differences between sprints were assessed through a 2-dimensional computerized motion analysis system (alpha level p
    • 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.
    • Endothelial function and stress response after simulated dives to 18 msw breathing air or oxygen

      Madden, Leigh A.; Chrismas, Bryna C.; Mellor, Duane; Vince, Rebecca V.; Midgley, Adrian W.; McNaughton, Lars R.; Atkin, Stephen L.; Laden, Gerard; University of Hull (Aerospace Medical Association, 2010-01)
      Decompression sickness is caused by gas bubbles released upon decompression. These bubbles have the potential to occlude blood vessels and damage the vascular endothelium. The aim of this study was to quantify damage to the vascular endothelium resulting from decompression by measuring endothelial microparticles (MP) and endothelial function.
    • Estimation of abdominal fat compartments by bioelectrical impedance: the validity of the ViScan measurement system in comparison with MRI

      Thomas, E. Louise; Collins, Adam L.; McCarthy, John; Fitzpatrick, Julie; Durighel, Giuliana; Goldstone, Anthony P.; Bell, Jimmy D.; Imperial College, London; University of Surrey; University of Bedfordshire (Nature Publishing Group, 2010-05)
      Abdominal obesity, more specifically increased intra-abdominal adipose tissue, is strongly associated with increased risk of metabolic disease. Bioelectrical impedance analysis (BIA) has been proposed as a potential method of determining individual abdominal fat compartments in the form of the commercially available ViScan measurement system (Tanita Corporation), but it has yet to be independently validated. The objective of this study was to analyse the validity of the ViScan to assess adult abdominal adiposity across a range of body fatness.
    • Evidence of altered cardiac electrophysiology following prolonged androgenic anabolic steroid use.

      Sculthorpe, Nicholas; Grace, Fergal; Jones, Peter; Davies, Bruce; University of Bedfordshire (2010-12)
      The non-therapeutic use of androgenic anabolic steroids (AAS) is associated with sudden cardiac death. Despite this, there is no proposed mechanism by which this may occur. Signal-averaged ECG (SAECG) allows the assessment of cardiac electrical stability, reductions of which are a known risk factor for cardiac arrhythmias. The aim of the present study was to examine cardiac electrical stability using SAECG in a group (n = 15) of long-term AAS users (AAS use 21.3 ± 3.1 years) compared with a group (n = 15) of age-matched weight lifters (WL) and age-matched sedentary controls [C (n = 15)]. AS, WL and C underwent SAECG analysis at rest and following an acute bout of exercise to volitional exhaustion. SAECGs were analyzed using a 40 Hz filter and were averaged over 200 beats. Results indicate a non-significant trend for increased incidence of abnormal SAECG measures at rest in AS (P = 0.55). However, AS demonstrated a significantly higher incidence of abnormalities of SAECG following exercise than C or WL (P < 0.05). In conclusion, the higher incidence of abnormal SAECG measurements immediately post-exercise in the AAS group places them at a greater risk of sudden death. The present study provides a strong contraindication to the use of AAS.
    • Exercise protocols to estimate Fatmax and maximal fat oxidation in children

      Zakrzewski-Fruer, Julia K.; Tolfrey, Keith (Human Kinetics, 2011-02)
      Consensus on the exercise protocol used to measure Fatmax (exercise intensity corresponding to maximum fat oxidation (MFO)) in children has not been reached. The present study compared Fatmax estimated using the 3 min incremental cycling protocol (3-INC) and a protocol consisting of several 10 min constant work rate exercise bouts (10-CWR) in 26 prepubertal children. Group Fatmax values were the same for 3-INC and 10-CWR (55% VO2peak) and 95% limits of agreement (LoA) were ± 7% VO2peak. Group MFO values were similar between protocols, although 95% LoA were -94 to 113 mg·min-1. While 3-INC provides a valid estimation of Fatmax compared with 10-CWR, caution should be exercised when estimating MFO in prepubertal children.
    • 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.
    • Exercise-induced dehydration with and without environmental heat stress results in increased oxidative stress

      Hillman, Angela R.; Vince, Rebecca V.; Taylor, Lee; McNaughton, Lars R.; Mitchell, Nigel; Siegler, Jason C. (NRC Research Press, 2011)
      While in vitro work has revealed that dehydration and hyperthermia can elicit increased cellular and oxidative stress, in vivo research linking dehydration, hyperthermia, and oxidative stress is limited. The purpose of this study was to investigate the effects of exercise-induced dehydration with and without hyperthermia on oxidative stress. Seven healthy male, trained cyclists (power output (W) at lactate threshold (LT): 199 ± 19 W) completed 90 min of cycling exercise at 95% LT followed by a 5-km time trial (TT) in 4 trials: (i) euhydration in a warm environment (EU-W, control), (ii) dehydration in a warm environment (DE-W), (iii) euhydration in a thermoneutral environment (EU-T), and (iv) dehydration in a thermoneutral environment (DE-T) (W: 33.9 ± 0.9 °C; T: 23.0 ± 1.0 °C). Oxidized glutathione (GSSG) increased significantly postexercise in dehydration trials only (DE-W: p < 0.01, DE-T: p = 0.03), and while not significant, total glutathione (TGSH) and thiobarbituric acid reactive substances (TBARS) tended to increase postexercise in dehydration trials (p = 0.08 for both). Monocyte heat shock protein 72 (HSP72) concentration was increased (p = 0.01) while lymphocyte HSP32 concentration was decreased for all trials (p = 0.02). Exercise-induced dehydration led to an increase in GSSG concentration while maintenance of euhydration attenuated these increases regardless of environmental condition. Additionally, we found evidence of increased cellular stress (measured via HSP) during all trials independent of hydration status and environment. Finally, both 90-min and 5-km TT performances were reduced during only the DE-W trial, likely a result of combined cellular stress, hyperthermia, and dehydration. These findings highlight the importance of fluid consumption during exercise to attenuate thermal and oxidative stress during prolonged exercise in the heat.
    • Fatmax in children and adolescents: a review

      Zakrzewski-Fruer, Julia K.; Tolfrey, Keith (Taylor and Francis, 2011)
      The purpose of this review is to summarise and critically examine the literature that has determined Fatmax in children and adolescents (young people). Maximising fat oxidation during exercise may be beneficial for health, particularly in the management of metabolic diseases such as obesity and type 2 diabetes. Exercise intensity largely determines fat oxidation during exercise. Fatmax is the relative exercise intensity that elicits the highest fat oxidation rate and has received increasing attention in recent years. Studies in young people have demonstrated that there is considerable inter-individual variation in Fatmax, which generally occurs between 30 and 60% of peak oxygen uptake. Factors that may influence Fatmax in young people include body composition, physical maturation, and exercise training. Several researchers have suggested that Fatmax and fat oxidation rates may be reduced in obese compared with non-obese young people.
    • Fluctuating asymmetry and preferences for sex-typical bodily characteristics

      Brown, William Michael; Price, M.E.; Kang, J.; Pound, N.; Zhao, Y.; Yu, H.; Brunel University; Higher Education Funding Council; British Academy Grant (2012-05-23)
      Body size and shape seem to have been sexually selected in a variety of species, including humans, but little is known about what attractive bodies signal about underlying genotypic or phenotypic quality. A widely used indicator of phenotypic quality in evolutionary analyses is degree of symmetry (i.e., fluctuating asymmetry, FA) because it is a marker of developmental stability, which is defined as an organism's ability to develop toward an adaptive end-point despite perturbations during its ontogeny. Here we sought to establish whether attractive bodies signal low FA to observers, and, if so, which aspects of attractive bodies are most predictive of lower FA. We used a 3D optical body scanner to measure FA and to isolate size and shape characteristics in a sample of 77 individuals (40 males and 37 females). From the 3D body scan data, 360° videos were created that separated body shape from other aspects of visual appearance (e.g., skin color and facial features). These videos then were presented to 87 evaluators for attractiveness ratings. We found strong negative correlations between FA and bodily attractiveness in both sexes. Further, sex-typical body size and shape characteristics were rated as attractive and correlated negatively with FA. Finally, geometric morphometric analysis of joint configurations revealed that sex-typical joint configurations were associated with both perceived attractiveness and lower FA for male but not for female bodies. In sum, body size and shape seem to show evidence of sexual selection and indicate important information about the phenotypic quality of individuals.
    • 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.
    • From Iron Girl to Sexy Goddess

      Wu, Ping (Palgrave MacMillan, 2009)
    • Gender differences in fundamental motor skill development in disadvantaged preschoolers from two geographical regions

      Goodway, Jacqueline D.; Robinson, Leah E.; Crowe, Heather (American Alliance for Health, Physical Education, Recreation and Dance, 2010-03)
      This study examined the influence of gender and region on object control (OC) and locomotor skill development. Participants were 275 midwestern African American and 194 southwestern Hispanic preschool children who were disadvantaged. All were evaluated on the Test of Gross MotorDevelopment-2 (Ulrich, 2000). Two, 2 Gender (girls, boys) x 2 Region (midwest, southwest) analyses of variance were conducted on OC and locomotor percentile rank. Both midwestern and southwestern preschoolers were developmentally delayed in locomotor and OC skills (< 30th percentile). There was a significant difference for gender (p < .0001) and Gender x Region interaction (p = .02) for OC skills. Boys outperformed girls in the midwestern and southwestern regions. For locomotor skills, there was a significant difference for region (p < .001), with midwestern preschoolers having better locomotor skills.
    • Girls looking for a ‘second home’: bodies, difference and places of inclusion

      Azzarito, Laura; Hill, Joanne (Taylor and Francis, 2012)
      This visual ethnographic research aimed to further understandings of ethnic-minority girls' emplaced embodiment by investigating the link between girls' physicality and their views of physical activity spaces in their communities. The research was conducted in a school located in an urban multicultural context in the Midlands region of the UK. Participants were 20 girls (19 ethnic-minority girls; 1 white girl) aged 14–15 from two single-sex physical education classes.
    • 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.