1,398 research outputs found

    The Effects of Vascular Occlusion Training on Respiratory Exchange Ratio and Energy Expenditure When Coupled With Cardiovascular Training

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    International Journal of Exercise Science 8(1) : 57-64, 2015. Vascular occlusion training is a novel training modality that has received considerable attention in the exercise science literature. The current study is the first of its kind to look at the effects of vascular occlusion training on substrate utilization when combined with aerobic training. This study examined the effects of pairing a vascular occlusion training protocol with a bout of submaximal aerobic exercise on energy expenditure (EE) and fuel use during exercise. Subjects performed a 20 minute bout of sub-maximal aerobic exercise either exclusively, or after performing a body weight squat protocol either with or without vascular occlusion. Peak lactate concentrations, EE and respiratory exchange ratio (RER) were all measured. A repeated measures analysis of variance was performed to look at differences among groups and interactions among protocols. The results suggest no difference in peak lactate (7.29 mmol/dl vs. 10.17 mmol/dl; F=0.946; p\u3e0.05) or EE (92.09 Kcals vs 93.48 Kcals; F=0.898 p\u3e0.05) among protocols. However, there does appear to be a shift in substrate utilization towards fatty acid oxidation by performing either a vascular occlusion training protocol (mean RER= 0.836) or a protocol of body weight squats (mean RER= 0.823) prior to aerobic training in comparison to performing aerobic training alone (mean RER= 0.881). There were, however, no significant differences between the occlusion protocol and the body weight squat protocol prior to the aerobic training. These results suggest that while there are no differences in overall caloric expenditure between protocols, performing either a resistance training protocol or a vascular occlusion training protocol shifts substrate utilization in favor of fatty acid oxidation over the oxidation of carbohydrates

    Hemodynamic and Cerebrovascular Responses to an Acute Bout of Blood Flow Restriction Resistance Exercise

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    Blood flow restriction (BFR) training is a novel exercise modality characterized by restricting blood flow to active muscles by the use of an occlusive device. A hallmark of this training is the use of lighter resistance loads, making it a potentially valuable tool for the elderly as well as patients exercising in a rehabilitative setting. Despite the growing interest in this novel mode of exercise, no investigation has comprehensively assessed the combined arterial pressure and cerebrovascular responses (flow and oxygenation) to BFR training, factors which may limit its application for cardiac and stroke rehabilitation. One concern about these applications is the potential for an amplification of the exercise pressor reflex, which could cause an unsafe rise in arterial blood pressure. The aim of this investigation was to compare the hemodynamic and cerebrovascular responses between BFR resistance exercise and traditional resistance exercise (TE). We hypothesized that the exercise-induced elevation in arterial pressure and cerebral blood flow would be attenuated with BFR, due to the use of lower workloads. Five healthy human volunteers (3 males, 2 females; age, 25.4±1.1 years) performed 3 sets of 10 repetitions of bilateral leg press with (BFR) or without (TE) bilateral blood flow restriction (220 mmHg cuff pressure), separated by 1-min rest periods (randomized, cross-over design). BFR was performed at 20% of 1 repetition maximum (1RM) while TE was performed at 65% of 1RM. Heart rate (HR) and arterial pressures were collected via ECG and finger photoplethysmography. Middle cerebral artery blood velocity (MCAv) was measured via transcranial Doppler ultrasound, and oxygen saturation of the frontal cortex (ScO2) was measured via near-infrared spectroscopy. Rate pressure product (RPP) was calculated as systolic arterial pressure multiplied by HR, and used as an index of myocardial oxygen demand. Mean arterial pressure (MAP) and RPP were both higher during TE compared with BFR during sets 2 and 3 (MAP: TE, 116±10 mmHg vs. BFR, 104±6 mmHg for BFR, P=0.05 (Set 3); RPP: TE, 16229±2387 mmHg*bpm vs. BFR, 11889±978 mmHg*bpm, P≤0.02 (Set 3)). While MCAv and ScO2 increased with exercise (

    Rural zoning in Missouri : basis, procedure, and effect

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    Extended conjugated microporous polymers for photocatalytic hydrogen evolution from water

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    Conjugated microporous polymers (CMPs) have been used as photocatalysts for hydrogen production from water in the presence of a sacrificial electron donor. The relative importance of the linker geometry, the co-monomer linker length, and the degree of planarisation were studied with respect to the photocatalytic hydrogen evolution rate

    The Effects of Vascular Occlusion Training on Respiratory Quotient and Energy Expenditure When Coupled with Cardiovascular Training

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    Purpose: The Purpose of this study was to determine the effects of pairing a vascular occlusion training protocol with a bout of cardiovascular training on substrate utilization and caloric expenditure in healthy adults. Methods: 5 healthy adults were recruited to report to the lab one day a week for the duration of two hours for four consecutive weeks. During the first session informed consent was collected, a VO2max test was performed, and a familiarization session with vascular occlusion training was conducted. The next three sessions were randomized for each subject but consisted of the following three protocols. During Protocol A the subject performed 5 sets of body weight squats to volitional fatigue while having blood flow occluded to the quadriceps via 2 thigh sized blood pressure cuffs set at a pressure of 200mm/Hg. 30 seconds of rest was allowed between each set and during this period the cuffs were re-inflated to 200mm/Hg if any pressure was lost throughout the previous set. After completion of the final set blood lactate levels were analyzed in 1 minute intervals via a lactate plus portable analyzer until peak lactate was observed. After completion of the last set the subject then began a 20 minute segment of cardiovascular treadmill walking at an intensity that corresponded to 40-70% of predetermined VO2max. VO2 and VCO2 were collected during the 20 minute exercise bout, the 10 min EPOC, and for 50 minutes post-EPOC. Respiratory exchange ratio and total caloric expenditure as calculated by the Weir equation were computed for all three time segments. During Protocol B the subject performed 5 body weight squats without vascular occlusion and then performed the same 20 minute bout at the same intensity. Peak [lactate] after completion of the final set, respiratory exchange ratio and total caloric expenditure were collected for all three time segments again. Lastly during protocol C the subject performed the 20 minutes of cardiovascular training at the same intensity without performing any form of resistance training prior to beginning. RER and total caloric expenditure were collected again for all three time segments. Results: A repeated measures ANOVA revealed that there were significant differences between the respiratory exchange ratio during exercise and during EPOC between protocols (pDiscussion: There appears to be a shift in substrate utilization as a result of performing a vascular occlusion training protocol prior to cardiovascular training as reflected in the difference in RER. During the EPOC there were no significant differences between the vascular occlusion training and the cardiovascular training not preceded by occlusion however there appears to be a shift in substrate utilization by performing body weight squats to failure without occlusion prior to cardiovascular training as reflected in RER

    Repression by Law

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    Structural Elucidation of Amorphous Photocatalytic Polymers from Dynamic Nuclear Polarization Enhanced Solid State NMR

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    Dynamic nuclear polarization (DNP) solid-state nuclear magnetic resonance (NMR) offers a recent approach to dramatically enhance NMR signals and has enabled detailed structural information to be obtained in a series of amorphous photocatalytic copolymers of alternating pyrene and benzene monomer units, the structures of which cannot be reliably established by other spectroscopic or analytical techniques. Large 13C cross-polarization (CP) magic angle spinning (MAS) signal enhancements were obtained at high magnetic fields (9.4–14.1 T) and low temperature (110–120 K), permitting the acquisition of a 13C INADEQUATE spectrum at natural abundance and facilitating complete spectral assignments, including when small amounts of specific monomers are present. The high 13C signal-to-noise ratios obtained are harnessed to record quantitative multiple contact CP NMR data, used to determine the polymers’ composition. This correlates well with the putative pyrene:benzene stoichiometry from the monomer feed ratio, enabling their structures to be understood

    Predictive Policing in China: An Authoritarian Dream of Public Security

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    China’s public security forces are employing more and more technology in their push for an ‘informatization (信息化)’ of their police work. The application of analytical techniques for solving past crimes or preventing future crimes based on big data analysis is thereby a key component of China’s approach for technology-led policing. China’s holistic policy approach for the purpose of maintaining social stability that is encompassing an ever-growing range of societal issues, the vast investments of its police forces in new technologies and its paramount objective of security, that clearly supersedes inter alia concerns of privacy or transparency, may be considered extremely conducive to the establishment of effective predictive policing in China. This paper however argues, that the application of predictive policing in China is heavily flawed as the systemic risks and pitfalls of predictive policing cannot be mitigated but are rather exacerbated by China’s approach towards policing and its criminal justice system. It is therefore to be expected that predictive policing in China will mainly be a more refined tool for the selective suppression of already targeted groups by the police and does not substantially reduce crime or increase overall security
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