1,232 research outputs found
Role of High-intensity Resistance Exercise in Vascular Inflammation in Recreationally Trained Men
Soluble intracellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) are known as vascular inflammatory markers and play a key role in the development of atherosclerosis. Although low to moderate intensity exercise may positively influence inflammatory markers, the role of high-intensity resistance exercise in sICAM-1 and sVCAM-1 has not been fully examined. The current study examined the effects of resistance exercise at different intensities (low vs. high) on acute responses of sICAM-1 and sVCAM-1. In a randomized, cross-over design, 10 recreationally trained (resistance-trained 3 to 6 days per week for at least one year) college-aged men performed a single bout of lower body resistance exercise, consisting of the leg press and unilateral knee extension exercises, at two different intensities (low intensity: 50% of 1-RM and high intensity: 80% of 1-RM). The volume of two intensities of exercise was similar. Overnight fasting blood samples were collected at baseline and 3-hr, 24-hr, and 48-hr post exercise (PE) for each exercise intensity to determine sICAM-1 and sVCAM-1. A 2 X 4 ANOVA with repeated measures was used to examine the mean differences in intensities and time on sICAM-1 and sVCAM-1, and the Least Significant Difference (LSD) tests were conducted as post hoc tests. If a significant interaction was found, the follow-up simple effects test was conducted. A p-value \u3c .05 was set for the statistical significance. Low-intensity resistance exercise did not significantly alter sICAM-1; however, during the high-intensity resistance exercise trial, sICAM-1 at 48-hr PE (364.85 ± 34.40 ng/ml) significantly (p = .037) decreased by 14.27% from 3-hr PE (425.60 ± 36.71 ng/ml). Following low-intensity resistance exercise, sVCAM-1 significantly (p = .001) increased by 27.6 % at 24-hr PE (p = .001) and remained elevated up to 48-hr PE (p = .001). In addition, sVCAM-1 at 24-hr PE (715.70 ± 38.14 ng/ml) and 48-hr PE (716.32 ± 34.79 ng/ml) for the low-intensity resistance exercise trial were significantly higher (p = .003 and p = .002, respectively) than the same time points of the high-intensity resistance exercise trial (24-hr PE: 532.57 ± 38.14 ng/ml and 48-hr PE: 533.18 ± 34.79 ng/ml). Thus, the current study suggests that high-intensity resistance exercise can also be an effective method to improve cardiovascular health since it reduced vascular inflammatory markers by decreasing sICAM-1 without altering sVCAM-1
A Solution to the Galactic Foreground Problem for LISA
Low frequency gravitational wave detectors, such as the Laser Interferometer
Space Antenna (LISA), will have to contend with large foregrounds produced by
millions of compact galactic binaries in our galaxy. While these galactic
signals are interesting in their own right, the unresolved component can
obscure other sources. The science yield for the LISA mission can be improved
if the brighter and more isolated foreground sources can be identified and
regressed from the data. Since the signals overlap with one another we are
faced with a ``cocktail party'' problem of picking out individual conversations
in a crowded room. Here we present and implement an end-to-end solution to the
galactic foreground problem that is able to resolve tens of thousands of
sources from across the LISA band. Our algorithm employs a variant of the
Markov Chain Monte Carlo (MCMC) method, which we call the Blocked Annealed
Metropolis-Hastings (BAM) algorithm. Following a description of the algorithm
and its implementation, we give several examples ranging from searches for a
single source to searches for hundreds of overlapping sources. Our examples
include data sets from the first round of Mock LISA Data Challenges.Comment: 19 pages, 27 figure
Tests of Bayesian Model Selection Techniques for Gravitational Wave Astronomy
The analysis of gravitational wave data involves many model selection
problems. The most important example is the detection problem of selecting
between the data being consistent with instrument noise alone, or instrument
noise and a gravitational wave signal. The analysis of data from ground based
gravitational wave detectors is mostly conducted using classical statistics,
and methods such as the Neyman-Pearson criteria are used for model selection.
Future space based detectors, such as the \emph{Laser Interferometer Space
Antenna} (LISA), are expected to produced rich data streams containing the
signals from many millions of sources. Determining the number of sources that
are resolvable, and the most appropriate description of each source poses a
challenging model selection problem that may best be addressed in a Bayesian
framework. An important class of LISA sources are the millions of low-mass
binary systems within our own galaxy, tens of thousands of which will be
detectable. Not only are the number of sources unknown, but so are the number
of parameters required to model the waveforms. For example, a significant
subset of the resolvable galactic binaries will exhibit orbital frequency
evolution, while a smaller number will have measurable eccentricity. In the
Bayesian approach to model selection one needs to compute the Bayes factor
between competing models. Here we explore various methods for computing Bayes
factors in the context of determining which galactic binaries have measurable
frequency evolution. The methods explored include a Reverse Jump Markov Chain
Monte Carlo (RJMCMC) algorithm, Savage-Dickie density ratios, the Schwarz-Bayes
Information Criterion (BIC), and the Laplace approximation to the model
evidence. We find good agreement between all of the approaches.Comment: 11 pages, 6 figure
No Differences in Strength Improvements Following Low- or High-Volume Resistance Training
Resistance training is a widely used modality for improving muscular strength and reducing risks of injury, which is vital to counteracting physical declines associated with aging and poor health. Despite this, the minimal effective training dose for improving muscular strength has yet to be fully elucidated. PURPOSE: The purpose of this study was to examine the role of training volume (number of sets per session) on muscular strength changes following 8 weeks of progressive resistance training. METHODS: Fourteen and 12 trained males (Mean±SD; Age: 23±3y) and females (Age: 20±1y) participated in 8 weeks of supervised 3x/week progressive resistance training. Experimental sessions consisted of 3-5 repetition maximum testing both pre- and post-intervention, in accordance with the protocol outlined by the NSCA, in the following exercises: leg press (LP), bench press (BP), horizontal row (ROW), barbell Romanian deadlift (RDL), dumbbell overhead press (OHP), and lat pulldown (LAT). Following baseline strength testing, each participant was randomly allocated to either a low volume (LV; n=12 (5F)) or high volume (HV; n=14 (7F)) training group, completing 2 or 4 sets per exercise per training visit, respectively. Across all 8 weeks, participants completed each lift twice weekly, and loads were adjusted based on exercise performance using the autoregulated progressive resistance exercise protocol. Each group completed the same repetitions in their first sets, but completed the last set of every exercise until volitional failure. Percent change for each exercise was calculated as the difference between baseline strength (kgs) and post-training strength (kgs), expressed as a percentage of baseline strength. To examine the effect of group and exercise on the change in strength, a 2 (Group) × 6 (Exercise) analysis of covariance (ANCOVA) was performed, covarying for pre-test strength. In the event of a significant F test, the Bonferroni-corrected dependent-samples t-test was used. Values are presented as estimated marginal means ± standard error. RESULTS: There was no significant Group × Exercise interaction effect on percent strength change (p=0.754), nor a main effect of Group (p=0.397). However, there was a significant effect of Exercise (p\u3c0.001). Post-hoc analyses indicated, when collapsing across training groups, improvements in strength were greater in LP when compared to BP (40.6±6.8%; p\u3c0.001), RDL (26.9±6.1%; p\u3c0.001), OHP (37.4±7.9%; p\u3c0.001), and LAT (22.7±6.8%; p=0.015). Additionally, greater strength improvements were seen in ROW when compared to BP (29.7±4.5%, p\u3c0.001), RDL (16.0±4.6%, p\u3c0.001), and OHP (26.5±4.8%, p\u3c0.001). Finally, LAT experienced greater strength increases than both BP (17.8±4.5%, p\u3c0.01) and OHP (14.6±4.7%, p=0.036). There were no additional significant differences between exercises (p=0.054-0.999). CONCLUSION: Our findings suggest that a resistance training volume of as few as 2 sets per exercise twice weekly is adequate to induce muscular strength adaptations in previously trained young adults. Further examination is needed to determine if upper and lower body exercises require differing volumes to elicit similar adaptations
The Positive Effects of Acute Resistance Exercise on Blood Lipid Profiles in College-Aged Men
Low- to moderate-intensity exercise has been widely recommended for people at any age to improve cardiovascular health due to its positive effects on blood lipids and lipoproteins. Recently, many people have been participating in not only low- to moderate-intensity, but high-intensity exercise as well in order to improve their cardiovascular health. However, it is unclear whether high-intensity exercise, particularly resistance exercise, can positively influence blood lipids and lipoproteins. Purpose: The current study examined the effects of low- and high-intensity of resistance exercise on changes in blood lipids and lipoproteins. Methods: In a randomized, cross-over design, 10 healthy recreationally resistance-trained (at least 3 to 6 days per week for a minimum of one year) college-aged men participated in the study. The participants performed a lower body resistance exercise, consisting of the leg press and unilateral knee extension, at two different exercise intensities (low-intensity: 50% of 1-RM and high-intensity: 80% of 1-RM). The volume of the intensities of exercise was similar. Overnight fasting blood samples were collected at baseline and 3-hr, 24-hr, and 48-hr post exercise for each intensity to determine blood lipids and lipoproteins (TC, Lp(a), VLDL-C, LDL-C, and HDL-C). A 2 (intensity) X 4 (time) ANOVA with repeated measures was used to examine the mean differences in intensity and time on blood lipids and lipoproteins. The Bonferroni pairwise comparisons were conducted as post hoc to locate the significant mean differences. If a significant interaction was found, the follow-up simple effects test was conducted. A p-value \u3c .05 was set for the statistical significance. Results: Either low- or high-intensity resistance exercise did not significantly alter Lp(a), VLDL-C, or HDL-C. However, regardless of the intensity, LDL (p = .045) and TC (p = .028) significantly decreased by 7.90 (8.76 ± 0.32 mg/dL) and 6.80% (11.34 ± 0.93 mg/dL), respectively, at 48-hr post exercise. Conclusion: Regardless of the intensity level, resistance exercise may positively alter blood lipid profiles by decreasing TC and LDL-C in recreationally-trained men. Therefore, the current study suggests that high-intensity resistance exercise can also be an effective method to improve cardiovascular health
A Review of Weight Control Strategies and Their Effects on the Regulation of Hormonal Balance
The estimated prevalence of obesity in the USA is 72.5 million adults with costs attributed to obesity more than 147 billion dollars per year. Though caloric restriction has been used extensively in weight control studies, short-term success has been difficult to achieve, with long-term success of weight control being even more elusive. Therefore, novel approaches are needed to control the rates of obesity that are occurring globally. The purpose of this paper is to provide a synopsis of how exercise, sleep, psychological stress, and meal frequency and composition affect levels of ghrelin, cortisol, insulin GLP-1, and leptin and weight control. We will provide information regarding how hormones respond to various lifestyle factors which may affect appetite control, hunger, satiety, and weight control
Effects of Capsaicin and Evodiamine Ingestion on Energy Expenditure and Fat Oxidation at Rest and After Moderately-Intense Exercise in Young Men
Capsaicin and evodiamine are two thermogenic agents each recognized for their ability to stimulate the sympathetic nervous system and are thus found in many dietary supplements. Therefore, the purpose of this study was to observe the effects that capsaicin and evodiamine have on hemodynamics, energy expenditure, and markers of lipid oxidation while at rest and after a single bout of moderate-intensity exercise in young men. In a randomized, cross-over design, 11 men orally ingested 500 mg of capsaicin, evodiamine, or placebo while at rest after 30 minutes of resting energy expenditure assessment using open-circuit spirometry. After an additional 30 minutes of rest after supplement ingestion, resting energy expenditure was assessed again for 30 minutes. After the second resting energy expenditure assessment, treadmill exercise was performed until expending approximately 500 kilocalories (~30 minutes) at 65% peak oxygen consumption. Energy expenditure was assessed for another 30 minutes into the post-exercise period. Heart rate and blood pressure, core temperature, and venous blood samples were obtained 30 minutes before and one hour after supplement ingestion (i.e. immediately pre-exercise), and immediately after and 45 minutes post-exercise. Markers of lipid oxidation (serum glycerol, free fatty acids, serum glucose, epinephrine, and norepinephrine) were determined spectrophotometrically and with ELISA. Two-way analyses of variance (ANOVA) were performed for each dependent variable (p ≤ 0.05). Significant main effects for Time existed for hemodynamics, energy expenditure, serum catecholamines and markers of fat oxidation immediately following exercise (p \u3c 0.05). However, no significant Supplement x Time interactions were noted for any criterion variable (p \u3e 0.05), suggesting no preferential difference between supplements. Neither capsaicin nor evodiamine, at a single dose of 500 mg, are effective at inducing thermogenesis and increasing fat oxidation at rest or during exercise in young men
Effects of 28 days of resistance exercise while consuming commercially available pre- and post-workout supplements, NO-Shotgun® and NO-Synthesize® on body composition, muscle strength and mass, markers of protein synthesis, and clinical safety markers in males
<p>Abstract</p> <p>Purpose</p> <p>The effects of 28 days of heavy resistance training while ingesting the pre- and post-workout supplements, NO-Shotgun<sup>® </sup>and NO-Synthesize<sup>® </sup>were determined on body composition, muscle strength and mass, markers of protein synthesis, and clinical safety markers.</p> <p>Methods</p> <p>Nineteen non-resistance-trained males participated in a resistance training program 4 times/week for 28 days while either ingesting 27 g/day of carbohydrate (CARB) or NO-Shotgun<sup>® </sup>30 min pre-exercise and 27 g/day of carbohydrate or NO- Synthesize<sup>® </sup>30 min post-exercise (NOSS). Data were analyzed with separate 2 × 2 ANOVA (p < 0.05).</p> <p>Results</p> <p>Total body mass was increased in both groups (p = 0.001), but not different between groups. Fat mass was unchanged with CARB, but NOSS decreased fat mass (p = 0.026). Both groups increased fat-free mass (p = 0.001); however, the increases were greater with NOSS (p = 0.023). NOSS underwent greater increases in upper-body (p = 0.023) and lower-body (p = 0.035) strength than CARB. Myofibrillar protein significantly increased in both groups (p = 0.041), with NOSS being greater than CARB (p = 0.049). All of the MHC isoforms were significantly increased in both groups; however, NOSS was greater than CARB for MHC 1 (p = 0.013) and MHC 2A (p = 0.046). All of the myogenic regulatory factors were significantly increased in both groups; however, NOSS was greater than CARB for Myo-D (p = 0.038) and MRF-4 (p = 0.001). For the whole blood and serum clinical chemistry markers, all variables remained within normal clinical ranges.</p> <p>Conclusions</p> <p>Heavy resistance training for 28 days, with NO-Shotgun<sup>® </sup>and NO-Synthesize<sup>® </sup>ingested before and after exercise, respectively, significantly improved body composition and increased muscle mass and performance without abnormally impacting any of the clinical chemistry markers.</p
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