2,037 research outputs found

    Strongman training – Needs analysis and integration into strength and conditioning programming: part 2.

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    The article aims to evaluate the integration of strongman based exercises within the practice of strength and conditioning. It should give the reader a clear understanding of the specific physiological and biomechanical traits of each of the exercises discussed in the previous article. This information will then be used to discuss its amalgamation within traditional based exercises within the planning of a periodised programme for strength and conditioning practitioners

    Strongman training – a rationale for its inclusion in strength & conditioning: part 1

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    This article, the first in a two-part series, aims to introduce the concepts of strongman-type training relative to some of the exercises adopted. It should give the reader a detailed background into the evolution of strongman training with a strong rationale for its inclusion within the practice of strength and conditioning

    The timing of maternal depressive symptoms and child cognitive development: a longitudinal study.

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    Background: Maternal depression is known to be associated with impairments in child cognitive development, although the effect of timing of exposure to maternal depression is unclear. Methods: Data collected for the Avon Longitudinal Study of Parents and Children, a longitudinal study beginning in pregnancy, included self-report measures of maternal depression the Edinburgh Postnatal Depression Scale, completed on 6 occasions up to 3 years of age, and IQ of the index child (WISC) measured at aged 8 years. We used these data to assign women to 8 groups according to whether depression occurred in the antenatal, postnatal, preschool period, any combination of these times, or not at all. We compared a model comprising all patterns of depression (saturated model) with models nested within this to test whether there is a relationship between depression and child cognitive development and, if so, whether there is a sensitive period. We then investigated the relationship with child IQ for each model, following adjustment for confounders. Results: Six thousand seven hundred and thirty-five of 13,615 children from singleton births (49.5%, of eligible core sample) attended a research clinic at 8 years and completed a WISC with a score ≄ 70. A total of 5,029 mothers of these children had completed mood assessments over the 3 time periods. In unadjusted analyses, all three sensitive period models were as good as the saturated model, as was an accumulation model. Of the sensitive period models, only that for antenatal exposure was a consistently better fit than the accumulation model. After multiple imputation for missing data (to n = 6,735), there was no effect of postnatal depression on child IQ independent of depression at other times [-0.19 IQ points, 95% confidence interval (CI) -1.5 to 1.1 points]. There was an effect of antenatal depression (-3.19 IQ points, 95% CI: -4.33 to -2.06) which attenuated following adjustment (-0.64 IQ points, 95% CI: -1.68 to 0.40). Conclusions: The postnatal period is not a sensitive one for the effect of maternal depression on child cognitive development. © 2011 The Authors. Journal of Child Psychology and Psychiatry

    Detailed design of a quiet high flow fan

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    A single stage fan was designed to demonstrate the noise abatement properties of near-sonic inlet flow and long-chord stator vanes for the reduction of both upstream and downstream propagated fan source noise. It is designed to produce a pressure ratio of 1.653:1 with an adiabatic efficiency of 83.9%. The fan has a 508 mm inlet diameter with a hub/tip ratio of 0.426 and a design tip speed of 533.4 m/sec. The design inlet specific flow rate is 219.71 kg/sec sq m and there are 10 tandem stator vanes with a combined aspect ratio of 0.54

    The effect of isometric exercise training on arterial stiffness: A randomized crossover controlled study

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    Isometric exercise training (IET) is an effective intervention for the management of resting blood pressure (BP). However, the effects of IET on arterial stiffness remain largely unknown. Eighteen unmedicated physically inactive participants were recruited. Participants were randomly allocated in a cross-over design to 4 weeks of home-based wall squat IET and control period, separated by a 3-week washout period. Continuous beat-to-beat hemodynamics, including early and late systolic (sBP 1 and sBP 2, respectively) and diastolic blood pressure (dBP) were recorded for a period of 5 min and waveforms were extracted and analyzed to acquire the augmentation index (AIx) as a measure of arterial stiffness. sBP 1 (-7.7 ± 12.8 mmHg, p = 0.024), sBP 2 (-5.9 ± 9.9 mmHg, p = 0.042) and dBP (-4.4 ± 7.2 mmHg, p = 0.037) all significantly decreased following IET compared to the control period. Importantly, there was a significant reduction in AIx following IET (-6.6 ± 14.5%, p = 0.02) compared to the control period. There were also adjacent significant reductions in total peripheral resistance (-140.7 ± 65.8 dynes·cm-5, p = 0.042) and pulse pressure (-3.8 ± 4.2, p = 0.003) compared to the control period. This study demonstrates an improvement in arterial stiffness following a short-term IET intervention. These findings have important clinical implications regarding cardiovascular risk. Mechanistically, these results suggest that reductions in resting BP following IET are induced via favorable vascular adaptations, although the intricate details of such adaptations are not yet clear

    Reproducibility of limb power outputs and cardiopulmonary responses to exercise using a novel swimming training machine

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    The purpose of this study was to determine the reproducibility of limb power output and cardiopulmonary responses, to incremental whole-body exercise using a novel swimming training machine. Eight swimmers with a mean age of 23.7 ± 4.6 (yrs), stature 1.77 ± 0.13 (m) and body mass of 74.7 ± 2.8 (kg) gave informed consent and participated in repeat exercise testing on the machine. All subjects performed two incremental exercise tests to exhaustion using front crawl movements. From these tests peak oxygen consumption (VO2peak), peak heart rate (HRpeak), peak power output (Wpeak) and individual limb power outputs were determined. Results showed there were no significant differences between test 1 and 2 for any variable at exhaustion, and the CV% ranged from 2.8% to 3.4%. The pooled mean values were; VO2peak 3.7 ± 0.65 L.min-1, HRpeak 178.7 ± 6.6 b.min-1 and Wpeak 349.7 ± 16.5 W. The mean contributions to the total power output from the legs and arms were (37.3 ± 4.1 % and 62.7 ± 5.1 % respectively). These results show that it is possible to measure individual limb power outputs and cardopulmonary parameters reproducibly during whole-body exercise using this training machine, at a range of exercise intensitie

    A 4-week resistance training intervention improves stability, strength and neuromuscular activity in the lower limb: a case study of a cerebral palsy adult

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    Spastic diplegia, a form of cerebral palsy, is a neurological disorder that results in some degree of spasticity. It is often associated with impairment of both normal and selective movement of the lower limbs, and some degree of muscular weakness. Resistance training is an established exercise intervention with numerous neurological benefits. Evidence suggests that resistance training can positively improve stability in young populations with cerebral palsy. However, little research exists in adult populations, who are at greater risk of inactivity due to ageing and an increase in sedentarism. A single-subject (aged 35-years old, 150.5 centimetres, 81 kilograms) case-study was therefore carried out to investigate the effectiveness of a 4-week resistance training intervention on stability, neuromuscular activity and force output in a male adult with cerebral palsy. The variables measured were total centre of pressure displacement, peak torque in both the quadriceps and hamstrings and Surface Electromyography (sEMG) activity in the Rectus Femoris (RF), Vastus Lateralis (VL), Biceps Femoris (BF) and Semitendinosus (ST). The results demonstrated that a 4-week resistance training intervention reduced total centre of pressure displacement (-51.34%) whilst concomitantly increased sEMG output (RF left +80% right +22%, VL left +160% right +26%, BF left +203% right +44%, ST left +40% right +90%) and peak torque values (right leg extension -7%, right leg flexion +29%, left leg extension +11%, left leg flexion +42%). In conclusion, this case study demonstrates that a 4-week resistance training intervention improves the stability of the participant, possibly through neurological adaptations and improvements to lower limb strength

    Tropical–North Pacific Climate Linkages over the Past Four Centuries

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    Analyses of instrumental data demonstrate robust linkages between decadal-scale North Pacific and tropical Indo-Pacific climatic variability. These linkages encompass common regime shifts, including the noteworthy 1976 transition in Pacific climate. However, information on Pacific decadal variability and the tropical high-latitude climate connection is limited prior to the twentieth century. Herein tree-ring analysis is employed to extend the understanding of North Pacific climatic variability and related tropical linkages over the past four centuries. To this end, a tree-ring reconstruction of the December-May North Pacific index (NPI)-an index of the atmospheric circulation related to the Aleutian low pressure cell-is presented (1600-1983). The NPI reconstruction shows evidence for the three regime shifts seen in the instrumental NPI data, and for seven events in prior centuries. It correlates significantly with both instrumental tropical climate indices and a coral-based reconstruction of an optimal tropical Indo-Pacific climate index, supporting evidence for a tropical-North Pacific link extending as far west as the western Indian Ocean. The coral-based reconstruction (1781-1993) shows the twentieth-century regime shifts evident in the instrumental NPI and instrumental tropical Indo-Pacific climate index, and three previous shifts. Changes in the strength of correlation between the reconstructions over time, and the different identified shifts in both series prior to the twentieth century, suggest a varying tropical influence on North Pacific climate, with greater influence in the twentieth century. One likely mechanism is the low-frequency variability of the El Nino-Southern Oscillation (ENSO) and its varying impact on Indo-Pacific climate.</p

    K-Rational D-Brane Crystals

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    In this paper the problem of constructing spacetime from string theory is addressed in the context of D-brane physics. It is suggested that the knowledge of discrete configurations of D-branes is sufficient to reconstruct the motivic building blocks of certain Calabi-Yau varieties. The collections of D-branes involved have algebraic base points, leading to the notion of K-arithmetic D-crystals for algebraic number fields K. This idea can be tested for D0-branes in the framework of toroidal compactifications via the conjectures of Birch and Swinnerton-Dyer. For the special class of D0-crystals of Heegner type these conjectures can be interpreted as formulae that relate the canonical Neron-Tate height of the base points of the D-crystals to special values of the motivic L-function at the central point. In simple cases the knowledge of the D-crystals of Heegner type suffices to uniquely determine the geometry.Comment: 36 page

    Myocardial performance index as a measure of global left ventricular function improves following isometric exercise training in hypertensive patients

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    As the leading cause of cardiovascular disease and mortality, hypertension remains a global health problem. Isometric exercise training (IET) has been established as efficacious in reducing resting blood pressure (BP); however, no research to date has investigated its effects on the myocardial performance index (MPI). Twenty-four unmedicated hypertensive patients were randomized to 4 weeks of IET and a control period in a crossover design. Tissue Doppler imaging was used to acquire cardiac time intervals pre- and post-IET and during the control periods. IET significantly improved all measures of cardiac time intervals, including isovolumic relaxation time (83.1 ± 10.3 vs. 76.1 ± 11.2 ms, p = 0.006), isovolumic contraction time (84.8 ± 10.3 vs. 72.8 ± 6.4 ms, p < 0.001), ejection time (304.6 ± 30.2 vs. 321.4 ± 20.8 ms, p = 0.015) and the MPI (0.56 ± 0.09 vs. 0.47 ± 0.05, p < 0.001). This is the first study to demonstrate that IET significantly improves cardiac time intervals. These findings may have important clinical implications, highlighting the potential utility of IET in the management of cardiac health in hypertensive patients
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