Greg Atkinson

Teesside University, Middlesborough, England, United Kingdom

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Publications (209)670.47 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the study was to compare 3-year changes in physical performance between junior soccer players selected for an elite academy and age-matched controls. The 3-year changes in indicators of the physical performance were quantified in 12-16-year-old Premier League Academy (n=27) and non-academy soccer players (n=18). Data were analysed with an age-group×competitive level general linear model, covariate-adjusted for initial performance level and change in maturation. Covariate adjusted mean±SD changes were greater (standardised effect size>0.7) for the academy players in terms of countermovement jump (7.3±2.6 vs. 5.4±2.5 cm), 10 m sprint (- 0.15±0.05 vs. - 0.10±0.04 s), 20 m sprint (- 0.30±0.16 s vs. - 0.15±0.13 s), agility (- 0.19±0.01 s vs. - 0.08±0.08 s), repeated sprint (- 0.60±0.26 s vs. - 0.41±2.1 s) and intermittent endurance capacity (1 128±406 vs. 315±370 m). These data indicate that a 3-year programme of training in an elite soccer academy is associated with greater changes in physical performance indicators independently from the initial performance level of the child and change in maturation over the same period of time.
    International journal of sports medicine. 07/2014;
  • Greg Atkinson, Alan M Batterham
    Vascular Medicine 05/2014; 19(2):142-143. · 1.62 Impact Factor
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    ABSTRACT: To examine the effects of a simulated dawn during the last 30 min of sleep on the subsequent dissipation of sleep inertia and changes in simulated work and physical performance. Eight participants, who reported difficulty with morning waking, were administered in a random order to a control (C) and a dawn simulation (DS) trial (starting 30 min prior to waking). Subjective ratings of sleep quality and alertness were obtained alongside measures of cognitive performance (addition and reaction time tasks measured at 5, 30 and 75 min after waking at habitual workday times). Physical performance was also measured 35 min after waking using a self-paced cycling protocol. After waking in DS, perceived sleep quality was 1.16 ± 0.89 (p = 0.01) points higher compared with C. Ratings of alertness were significantly higher in DS than C throughout the testing period (p = 0.04). Cognitive performance improved in both trials as time awake increased (p < 0.0005). On average, participants completed a greater number of additions in DS compared with C (69.5 ± 15.3 vs 66.9 ± 16.7, p = 0.03). Reaction times were also faster in DS compared with C (0.81 ± 0.07 s vs 0.86 ± 0.06 s, p < 0.0005). The self-paced time-trial was completed 21.4 s (4.7 %) quicker in DS (p = 0.07). These data provide the first evidence that light exposure during the last 30 min of habitual sleep can increase subjective alertness and improve both cognitive and physical performance after waking.
    Arbeitsphysiologie 02/2014; · 2.66 Impact Factor
  • Greg Atkinson, Alan M Batterham
    International journal of cardiology 01/2014; · 6.18 Impact Factor
  • Greg Atkinson, Alan M Batterham
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    ABSTRACT: The percentage flow-mediated dilation index (FMD%) scales the increase in arterial diameter (Ddiff) as a constant proportion of baseline artery diameter (Dbase). We have demonstrated, albeit with small samples, that the scaling properties of FMD% can lead to biased inferences on endothelial dysfunction. Therefore, we aimed to investigate the underlying rationale and potential bias of FMD% using a selection of new examples from the large (n = 3499) and diverse Multi-Ethnic Study of Atherosclerosis (MESA). In this dataset, we found that smaller values of Ddiff are associated with larger values of Dbase, which contradicts the scaling properties of FMD%. Consequently, FMD% 'over-scales' and naturally generates an even stronger negative correlation between itself and Dbase. Using a data simulation, we show that this FMD%-Dbase correlation can be a statistical artefact due to inappropriate scaling. The new examples we present from MESA indicate that FMD% biases the differences in flow-mediated response between men and women, Framingham risk score categories, and diseased and healthy people. We demonstrate how FMD%, as an exposure for predicting cardiovascular disease, is confounded by its dependency on Dbase, which itself could be clinically important. This critical review, incorporating an allometric analysis of a large dataset, suggests that the FMD% index has a less-than-clear rationale, can itself generate the Dbase-dependency problem, provides biased estimates of differences in the flow-mediated response, complicates the interpretation of the flow-mediated protocol and clouds the causal pathway to vascular disease. These interpretative problems can be resolved by applying accepted allometric principles to the flow-mediated response.
    Vascular Medicine 10/2013; · 1.62 Impact Factor
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    ABSTRACT: Background: Individuals with a spinal cord injury (SCI) demonstrate altered circadian variation in thermoregulatory control. Recently, we reported that tetraplegia is associated with a blunted release of melatonin in the evening. In order to examine whether this finding relates to circadian thermoregulation, we compared the correlations between evening changes in melatonin, core and skin temperature between thoracic and cervical SCI and able-bodied participants. Methods: In 10 able-bodied, 9 paraplegic and 8 tetraplegic participants, we measured, between 1900 and 2300 h, core temperature, proximal skin temperature (above and below the level of the lesion) and physical activity. Salivary melatonin was also sampled during this period and analyzed using enzyme linked immunosorbant assay. Results: Between 1900 and 2300 h, core and upper limb skin temperature gradually decreased in all groups (p = 0.01). A significant group × time interaction was evident in lower body skin temperature (p = 0.03). Lower body skin temperature was significantly higher in able-bodied controls compared with tetraplegics between 1900 and 2000 h (p < 0.05). In able-bodied and paraplegic participants, the changes in melatonin and core temperature were inversely correlated (r = -0.44 and -0.54, respectively, both p = 0.01). Melatonin and mean skin temperature changes were also inversely correlated (able-bodied controls: r = -0.24; p = 0.05 and paraplegics: r = -0.30; p= 0.02). Conclusion: The inverse correlation between evening changes in melatonin and thermoregulation is of a similar magnitude in paraplegic and able-bodied controls. In contrast, changes in skin temperature, below the level of the lesion, are unrelated to changes in melatonin in tetraplegics.
    Chronobiology International 10/2013; · 4.35 Impact Factor
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    ABSTRACT: In keeping with this review-series theme, we question whether the morning surge in blood pressure (MSBP) is a benign response to the physiological challenges during the first 3 h after waking, or is it clinically important? Therefore, we scrutinise the circadian-related mechanisms, the measurement methods and the prognostic value of the MSBP. The MSBP is relatively small (<2 mmHg) under constant routine conditions. Nevertheless, the blood pressure response to exercise can be 8-14 mm Hg greater in the morning vs. afternoon, even when prior sleep is controlled. Systematic bias between MSBP methods can be >10 mmHg. The "sleep-trough" method provides the largest MSBP (≈25 mmHg), but the sensitivity of MSBP to a treatment/intervention depends largely on its repeatability. The repeatability standard deviation (SD) for most MSBP methods is ≈8 mm Hg. While the magnitude of this SD precludes the use of MSBP for diagnostic decisions on individual patients, sample sizes for future intervention studies may be feasible, depending on the minimal clinically important difference in MSBP. This difference is somewhat unclear given that a large MSBP has recently been reported to predict a reduced, rather than a higher, risk of cardiovascular disease, although this particular study has been criticised. The MSBP is also naturally correlated to changes in physical activity and nocturnal "dipping" status. Therefore, it is important to account for these potential confounders of the MSBP, so that more precise knowledge about its clinical significance is gained, thereby providing a sound rationale for physiological investigation and translational research.
    Arbeitsphysiologie 07/2013; · 2.66 Impact Factor
  • Heart Lung &amp Circulation 07/2013; · 1.25 Impact Factor
  • K Marrin, B Drust, W Gregson, G Atkinson
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    ABSTRACT: A melatonin-mediated reduction in body temperature could be useful as a "pre-cooling" intervention for athletes, as long as the melatonin dose is optimised so that substantial soporific effects are not induced. However, the melatonin-temperature dose-response relationship is unclear in humans. Individual studies have involved small samples of different sexes and temperature measurement sites. Therefore, we meta-analysed the effects of exogenous melatonin on body core temperature to quantify the dose-response relationship and to explore the influence of moderating variables such as sex and measurement site. Following a literature search, we meta-analysed 30 data-sets involving 193 participants and 405 ingestions of melatonin. The outcome was the mean difference (95 % confidence limits) in core temperature between the melatonin and placebo-controlled conditions in each study, weighted by the reciprocal of each standard error of the difference. The mean (95 % confidence interval) pooled reduction in core temperature was found to be 0.21 °C (0.18-0.24 °C). The dose-response relationship was found to be logarithmic (P < 0.0001). Doses of 0-5 mg reduced temperature by ~0.00-0.22 °C. Any further reductions in temperature were negligible with doses >5 mg. The pooled mean reduction was 0.13 °C (0.05-0.20 °C) for oral temperature vs 0.26 °C (0.20-0.32 °C) for tympanic and 0.22 °C (0.19-0.25 °C) for rectal temperature. In conclusion, our meta-regression revealed a logarithmic dose-response relationship between melatonin and its temperature lowering effects. A 5-mg dose of melatonin lowered core temperature by ~0.2 °C. Higher doses do not substantially increase this hypothermic effect and may induce greater soporific effects.
    Arbeitsphysiologie 06/2013; · 2.66 Impact Factor
  • Journal of Hypertension 05/2013; 31(5):1058. · 4.22 Impact Factor
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    ABSTRACT: We compared measurements of high-intensity activity during field-based training sessions in elite soccer players of different playing positions. Agreement was appraised between measurements of running speed alone and predicted metabolic power derived from a combination of running speed and acceleration. Data was collected during a 10-week phase of the competitive season from 26 English Premier League outfield players using global positioning system technology. High-intensity activity was estimated using the total distance covered at speeds >14.4 km · h-1 (TS) and the equivalent metabolic power threshold of >20 W · kg-1 (TP), respectively. We selected 0.2 as the -minimally important standardised difference between methods. Mean training session TS was 478±300 m vs. 727±338 m for TP (p<0.001). This difference was greater for central defenders (~ 85%) vs. wide defenders and attackers (~ 60%) (p<0.05). The difference between methods also decreased as the proportion of high-intensity distance within a training session increased (R2=0.43; p<0.001). We conclude that the high-intensity demands of soccer training are underestimated by traditional measurements of running speed alone, especially in training sessions or playing positions associated with less high-intensity activity. Estimations of metabolic power better inform the coach as to the true demands of a training session.
    International Journal of Sports Medicine 04/2013; · 2.27 Impact Factor
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    ABSTRACT: CONTEXT: The athlete's heart (AH) remains a popular topic of study. Controversy related to training-specific cardiac adaptation in male athletes, and continuing developments in imaging technology and scaling prompted this systematic review and meta-analysis. OBJECTIVE: To provide new insight in relation to: 1) cardiac adaptation to divergent training patterns in male athletes, 2) a developing research database using cardiac magnetic resonance (CMR) in athletes; 3) functional data derived from tissue-Doppler analysis as well as right ventricular (RV) and left atrial (LA) measurements in athletes; and 4) an awareness of the impact of body size on cardiac dimensions. STUDY DESIGN: Systematic review and meta-analysis of prospective trials. Data extraction performed by two researchers. DATA SOURCES: Pub Med, Medline, Scopus and ISI Web of knowledge scholarly data base. STUDY SELECTION: Prospective studies were included if they were echocardiographic or CMR trials of elite young male athletes, with clear indication of type of sports and passed a quality criteria checklist. RESULTS: All left ventricular (LV) structural parameters were higher in athletes than in controls. Only LV end-diastolic diameter and volume were higher in endurance athletes than in resistance athletes: 54.8 mm (95% CI 54.1 to 55.6) vs 52.4 mm (95% CI 51.2 to 53.6); p<0.001 and 171 ml (95% CI 157 to 185) vs 131 ml (95% CI 120 to 142); p<0.001, respectively. RV end-diastolic volume, mass and LA diameter were higher in endurance athletes than controls. LV end-diastolic volume was larger when CMR was used rather than echocardiography: 178 ml (95% CI Q7 162 to 194) vs 135 ml (95% CI 128 to 142); p<0.001. Meta-analysis regression models demonstrated positive and significant associations between body surface area (BSA) and LV mass, RV mass and LA diameter. CONCLUSIONS: Morphological features of the male AH were noted in both athlete groups. A training-specific pattern of concentric hypertrophy was not discerned in resistance athletes. Both imaging mode and BSA can have a significant impact on the interpretation of AH data.
    Heart (British Cardiac Society) 03/2013; · 5.01 Impact Factor
  • Greg Atkinson, Alan M Batterham
    Atherosclerosis 03/2013; · 3.71 Impact Factor
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    ABSTRACT: AIM: The ability to maintain arterial blood pressure when faced with a postural challenge has implications for the occurrence of syncope and falls. It has been suggested that posture-induced declines in the mechanical component of the baroreflex response drive reductions in cardiovagal baroreflex sensitivity associated with postural stress. However, these conclusions are largely based upon spontaneous methods of baroreflex assessment, the accuracy of which has been questioned. Therefore, the aim was to engage a partially-open loop approach to explore the influence of posture on the mechanical and neural components of the baroreflex. METHODS: In 9 healthy participants, we measured continuous blood pressure, heart rate, R-R interval, and carotid artery diameter during supine and standing postures. The modified Oxford method was used to quantify baroreflex sensitivity. RESULTS: In response to falling pressures, baroreflex sensitivity was similar between postures (P=0.798). In response to rising pressures, there was an attenuated (P=0.042) baroreflex sensitivity (mean ± SE) in the standing position (-0.70 ± 0.11 beats min-1 mmHg-1) compared with supine (-0.83 ± 0.06 beats min-1 mmHg-1). This was explained by a diminished (P=0.016) neural component whilst standing (-30.17 ± 4.16 beats min-1 mm-1) compared with supine (-38.23 ± 3.31 beats min-1 mm-1). These effects were consistent when baroreflex sensitivity was determined using R-R interval. CONCLUSION: Cardiovagal baroreflex sensitivity in response to rising pressures is reduced in young individuals during postural stress. Our data suggest that the mechanical component is unaffected by standing, and the reduction in baroreflex sensitivity is driven by the neural component. Acta Physiologica © 2013 Scandinavian Physiological Society.
    Acta Physiologica 02/2013; · 4.38 Impact Factor
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    ABSTRACT: Polycystic ovary syndrome (PCOS) is associated with cardiovascular disease. The contribution of the nitric oxide (NO) dilator system in cutaneous endothelial dysfunction is currently unknown in PCOS. Our aim was to examine whether women with PCOS demonstrate impaired cutaneous microvascular NO function and whether exercise training can ameliorate any impairment. Eleven women with PCOS (age: 29±7 yrs, BMI: 34±6 kg/m2) were compared with six healthy obese controls (age: 29±7 yrs; BMI: 34±5 kg/m2). Six women with PCOS (30±7y, 31±6kg/m2) then completed 16 weeks of exercise training. Laser Doppler flowmetry, combined with intra-dermal microdialysis of L-NG-monomethyl arginine, a NO antagonist, in response to incremental local heating of the forearm was assessed in PCOS and control women, and again in PCOS following exercise training. Cardiorespiratory fitness, HOMA-IR, hormone and lipid profiles were also assessed. Differences between PCOS and controls and changes with exercise were analysed using t-tests. Differences in NO contribution to cutaneous blood flow [expressed a % of maximal cutaneous vasodilation (CVCmax)] were analysed using general linear models. At 42°C heating, cutaneous NO-mediated vasodilation was attenuated by 17.5%CVCmax (95% CI=33.3, 1.7; P=0.03) in PCOS vs. control women. Exercise training improved cardiorespiratory fitness by 5.0ml/kg/min (95%CI=0.9, 9.2; P=0.03) and NO-mediated cutaneous vasodilation at 42°C heating by 19.6%CVCmax (95% CI=4.3, 34.9; P=0.02). Cutaneous microvascular NO function is impaired in PCOS women compared to obese matched controls but can be improved with exercise training.
    The Journal of Physiology 01/2013; · 4.38 Impact Factor
  • Heart (British Cardiac Society) 01/2013; in press. · 5.01 Impact Factor
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    ABSTRACT: Although bright light can alter circadian timing, the practicality and effectiveness of supplementary bright light for reducing jet-lag symptoms in world-class athletes is unclear. Therefore, we randomised 22 world class female footballers to a bright light intervention or control group before a flight from USA to Europe. Intra-aural temperature, grip strength, sleep and various jet-lag symptoms were measured serially. For 4 days, the intervention participants were exposed, in pairs within their rooms, to 2 500 lux of bright light at ≈50 cm for 45-60 min at a time-of-day predicted to accelerate circadian adjustment. On post-flight day 1, indoor light transiently increased intra-aural temperature by 0.38°C (95%CI: 0.16 to 0.60, P=0.001) and increased overall jet-lag rating by ≈1 unit. Light had negligible effects on functioning, diet, bowel and sleep symptoms, which varied substantially between- and within-subjects. In conclusion, supplementary indoor light administered within the schedule of world-class athletes was not substantially effective for reducing jet-lag symptoms after a flight from the USA-Europe. Ours is the first study of the practical effectiveness of supplementary bright light in world class athletes, although sample size was naturally small, compromises were required to implement the intervention and there appears to be large inter-individual variation in the perception of what constitutes jet-lag.
    International Journal of Sports Medicine 12/2012; · 2.27 Impact Factor
  • Greg Atkinson, Alan M Batterham
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    ABSTRACT: The negative correlation between percent flow-mediated dilation (FMD%) and baseline diameter (D(base)) has only recently been recognised as a fundamental ratio-scaling problem, which is not resolved by significance-testing of D(base) inequality between groups/conditions, nor by covariate-adjusting FMD% itself by D(base). It is resolved appropriately by allometric scaling of the relationship between peak diameter (D(peak)) and D(base) using statistical models. Therefore, we extracted data from a seminal study on FMD%, and re-analysed it using allometric methods. We found that D(peak) did not increase as a constant proportion of D(base), rendering FMD% a biased estimator of differences in endothelial function between artery sites (brachial vs femoral) and age-groups (children vs. adults). The allometric expression was D(peak)/D(base)(≈ 0.90), rather than a simple ratio. In agreement with our previous research, a proper allometric perspective on FMD led to unbiased estimates of endothelial function, with full adjustment for the influence of baseline diameter.
    Atherosclerosis 12/2012; · 3.71 Impact Factor
  • G Atkinson, A M Batterham, W G Hopkins
    International Journal of Sports Medicine 12/2012; 33(12):949. · 2.27 Impact Factor

Publication Stats

5k Citations
670.47 Total Impact Points

Institutions

  • 2010–2014
    • Teesside University
      • • School of Health and Social Care
      • • School of Social Sciences and Law
      Middlesborough, England, United Kingdom
  • 2013
    • University of Western Sydney
      • School of Science and Health
      Penrith, New South Wales, Australia
  • 2011–2013
    • Edge Hill University
      Ormskirk, England, United Kingdom
  • 1993–2013
    • Liverpool John Moores University
      • • Research Institute for Sport and Exercise Sciences (RISES)
      • • School of Sport and Exercise Sciences
      Liverpool, ENG, United Kingdom
  • 2012
    • Radboud University Medical Centre (Radboudumc)
      Nymegen, Gelderland, Netherlands
    • Radboud University Nijmegen
      • Department of Physiology
      Nijmegen, Provincie Gelderland, Netherlands
  • 2008–2011
    • University of Otago
      • • Department of Surgery and Anaesthesia (Wellington)
      • • Department of Physiology
      Dunedin, Otago, New Zealand
    • University of Tabriz
      Tebriz, East Azarbaijan, Iran
  • 2009
    • Kent State University
      Kent, Ohio, United States
  • 2007
    • University of Wolverhampton
      • School of Sport, Performing Arts and Leisure
      Wolverhampton, ENG, United Kingdom
  • 2006
    • Brunel University
      • Centre for Sports Medicine and Human Performance
      London, ENG, United Kingdom
  • 2004
    • English Institute of Sport
      Manchester, England, United Kingdom
  • 2003–2004
    • Loughborough University
      Loughborough, England, United Kingdom
    • Cardiff University
      Cardiff, Wales, United Kingdom
  • 2001
    • Durham University
      Durham, England, United Kingdom
  • 1996–1998
    • The University of Manchester
      • Manchester Medical School
      Manchester, England, United Kingdom