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## Comparative effect of two whole-body vibration exercise programs on the neuromuscular function and fitness in young women

Raimundo, Armando; Batalha, Nuno; Tomás-Carús, Pablo; Leal, Alejo; Gusi, Narcis
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
36.18%
Introduction Vibratory exercises are increasingly used in sport training and physical rehabilitation. This study aims to determine the comparative effects of two vibratory frequencies on the neuromuscular leg function in healthy young active females. Methods Twenty-four women (aged 21.9 ± 2.6 years; weight 59.9 ± 7.1 kg) were randomly assigned into 3 groups of 8 subjects: group 25 Hz (G25), group 30Hz (G30), and control group (CG). All intervention programs consisted of 30 training sessions within a 10-week period.The peak torque at 60º/s in concentric and eccentric actions were measured by an isokinetic dynamometer (Biodex System-3, Biodex Corp., Shirley, NY, USA). Fitness tests such Squat Jump, Counter Movement Jump, Stair-Climbing 10-stairs time, 10-m walking time, were also performed. The effects of the interventions were analysed by an adaptation of Analysis of Covariance adjusted by weight. Results Vibratory training at 25Hz induced a significant reduction of peak torque in concentric contraction at the velocity of 60°.sec-l and improved the stair-climbing capacity. All other variables remained unchanged in the three groups. Discussion The results of the present study suggest that 10-weeks of Whole Body Vibration (WBV) programs improved ballistic strength but not isokinetic strength. Some studies with similar frequencies (between 25 Hz and 40 Hz) reported an improvement on vertical jump after 4 and 8 months (Torvinen et al....

## Deterministic and Stochastic Regimes of Asexual Evolution on Rugged Fitness Landscapes

Jain, Kavita; Krug, Joachim
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.18%
We study the adaptation dynamics of an initially maladapted asexual population with genotypes represented by binary sequences of length L. The population evolves in a maximally rugged fitness landscape with a large number of local optima. We find that whether the evolutionary trajectory is deterministic or stochastic depends on the effective mutational distance deff up to which the population can spread in genotype space. For deff = L, the deterministic quasi-species theory operates while for deff < 1, the evolution is completely stochastic. Between these two limiting cases, the dynamics are described by a local quasi-species theory below a crossover time T× while above T× the population gets trapped at a local fitness peak and manages to find a better peak via either stochastic tunneling or double mutations. In the stochastic regime deff < 1, we identify two subregimes associated with clonal interference and uphill adaptive walks, respectively. We argue that our findings are relevant to the interpretation of evolution experiments with microbial populations.

## The pace of evolution across fitness valleys

Gokhale, Chaitanya; Iwasa, Yoh; Nowak, Martin A.; Traulsen, Arne
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.32%
How fast does a population evolve from one fitness peak to another? We study the dynamics of evolving, asexually reproducing populations in which a certain number of mutations jointly confer a fitness advantage. We consider the time until a population has evolved from one fitness peak to another one with a higher fitness. The order of mutations can either be fixed or random. If the order of mutations is fixed, then the population follows a metaphorical ridge, a single path. If the order of mutations is arbitrary, then there are many ways to evolve to the higher fitness state. We address the time required for fixation in such scenarios and study how it is affected by the order of mutations, the population size, the fitness values and the mutation rate.

## The Pace of Evolution Across Fitness Valleys

Gokhale, Chaitanya S.; Iwasa, Yoh; Nowak, Martin A.; Traulsen, Arne
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
36.32%
How fast does a population evolve from one fitness peak to another? We study the dynamics of evolving, asexually reproducing populations in which a certain number of mutations jointly confer a fitness advantage. We consider the time until a population has evolved from one fitness peak to another one with a higher fitness. The order of mutations can either be fixed or random. If the order of mutations is fixed, then the population follows a metaphorical ridge, a single path. If the order of mutations is arbitrary, then there are many ways to evolve to the higher fitness state. We address the time required for fixation in such scenarios and study how it is affected by the order of mutations, the population size, the fitness values and the mutation rate.; Mathematics; Organismic and Evolutionary Biology

## Mediating Influence of Physical Fitness on the Relationship between Academic Performance and Motor Proficiency

Alexander, Ryan
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
Relevância na Pesquisa
46.18%
We explored the potential mediating influence of physical fitness on the relationship between academic performance and motor proficiency in children. 1864 students (F:926, M:938, age 11.91 (SD:0.34). Academic achievement was derived from an average of standardized tests of reading, writing, and math. The Bruininks-Oseretsky Test of Motor Performance (short-form) determined motor proficiency. Fitness (peak oxygen uptake) was established with the Léger 20-m Shuttle Run Test. OLS regression identified several significant predictors of academic performance. After controlling for age (p=0.0135), gender (p<0.0001), and parental education (p<0.0001), motor proficiency (p<0.0001), was significant. After adding physical fitness (p=0.0030) to the model the effect of motor proficiency remained significant however the point estimate was reduced from 0.0034 (p<0.0001) to 0.0026 (p<0.0001). These results suggest that physical fitness plays a mediating role on the relationship between academic performance and motor proficiency although both aerobic fitness and motor proficiency have independent roles.

## The role of physical activity and perceived adequacy on cardiorespiratory fitness in children with developmental coordination disorder

Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
Relevância na Pesquisa
36.36%
Evidence suggests that children with developmental coordination disorder (DCD) have lower levels of cardiorespiratory fitness (CRF) compared to children without the condition. However, these studies were restricted to field-based methods in order to predict V02 peak in the determination of CRF. Such field tests have been criticised for their ability to provide a valid prediction of V02 peak and vulnerability to psychological aspects in children with DCD, such as low perceived adequacy toward physical activity. Moreover, the contribution of physical activity to the variance in V02 peak between the two groups is unknown. The purpose of our study was to determine the mediating role of physical activity and perceived adequacy towards physical activity on V02 peak in children with significant motor impairments. This prospective case-control design involved 122 (age 12-13 years) children with significant motor impairments (n=61) and healthy matched controls (n=61) based on age, gender and school location. Participants had been previously assessed for motor proficiency and classified as a probable DCD (p-DCD) or healthy control using the movement ABC test. V02 peak was measured by a progressive exercise test on a cycle ergometer. Perceived adequacy was measured using a 7 -item subscale from Children's Selfperception of Adequacy and Predilection for Physical Activity scale. Physical activity was monitored for seven days with the Actical® accelerometer. Children with p-DCD had significantly lower V02 peak (48.76±7.2 ml/ffm/min; p:50.05) compared to controls (53.12±8.2 ml/ffm/min)...

## Exercise-induced improvements in cardiorespiratory fitness and heart rate response to exercise are impaired in overweight/obese postmenopausal women

CIOLAC, Emmanuel Gomes; GREVE, Júlia Maria D'Andréa
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.33%
OBJECTIVE: The purpose of this study was to compare the heart rate response to exercise and the exercise-induced improvements in muscle strength, cardiorespiratory fitness and heart rate response between normal-weight and overweight/obese postmenopausal women. METHODS: Sedentary women (n = 155) were divided into normal-weight (n = 79; BMI <25 kg/m²; 58.3 + 8.6 years) and overweight/obese (n = 76; BMI >25 kg/m²; 58.3 + 8.6 years) groups, and have their 1-repetition maximum strength (adjusted for body mass), cardiorespiratory fitness and heart rate response to a graded exercise test compared before and after 12 months of a three times-per-week exercise-training program. RESULTS: Overweight/obese women displayed decreased upper and lower extremity muscle strengths, decreased cardiorespiratory fitness, and lower peak and reserve heart rates compared to normal-weight women. After follow-up, both groups improved their upper (32.9% and 41.5% in normal-weight and overweight/obese women, respectively) and lower extremity(49.5% and 47.8% in normal-weight and overweight/obese women, respectively) muscle strength. However, only normal-weight women improved their cardiorespiratory fitness (6.6%) and recovery heart rate (5 bpm). Resting, reserve and peak heart rates did not change in either group. CONCLUSIONS: Overweight/obese women displayed impaired heart rate response to exercise. Both groups improved muscle strength...

## The Frequency of Fitness Peak Shifts Is Increased at Expanding Range Margins Due to Mutation Surfing

Burton, Olivia J.; Travis, Justin M. J.
Fonte: Genetics Society of America Publicador: Genetics Society of America
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.37%
Dynamic species' ranges, those that are either invasive or shifting in response to environmental change, are the focus of much recent interest in ecology, evolution, and genetics. Understanding how range expansions can shape evolutionary trajectories requires the consideration of nonneutral variability and genetic architecture, yet the majority of empirical and theoretical work to date has explored patterns of neutral variability. Here we use forward computer simulations of population growth, dispersal, and mutation to explore how range-shifting dynamics can influence evolution on rugged fitness landscapes. We employ a two-locus model, incorporating sign epistasis, and find that there is an increased likelihood of fitness peak shifts during a period of range expansion. Maladapted valley genotypes can accumulate at an expanding range front through a phenomenon called mutation surfing, which increases the likelihood that a mutation leading to a higher peak will occur. Our results indicate that most peak shifts occur close to the expanding front. We also demonstrate that periods of range shifting are especially important for peak shifting in species with narrow geographic distributions. Our results imply that trajectories on rugged fitness landscapes can be modified substantially when ranges are dynamic.

## Exercise-induced improvements in cardiorespiratory fitness and heart rate response to exercise are impaired in overweight/obese postmenopausal women

Ciolac,Emmanuel Gomes; Greve,Júlia Maria D'Andréa
Tipo: Artigo de Revista Científica Formato: text/html
Relevância na Pesquisa
36.33%
OBJECTIVE: The purpose of this study was to compare the heart rate response to exercise and the exercise-induced improvements in muscle strength, cardiorespiratory fitness and heart rate response between normal-weight and overweight/obese postmenopausal women. METHODS: Sedentary women (n = 155) were divided into normal-weight (n = 79; BMI <25 kg/m²; 58.3 + 8.6 years) and overweight/obese (n = 76; BMI >25 kg/m²; 58.3 + 8.6 years) groups, and have their 1-repetition maximum strength (adjusted for body mass), cardiorespiratory fitness and heart rate response to a graded exercise test compared before and after 12 months of a three times-per-week exercise-training program. RESULTS: Overweight/obese women displayed decreased upper and lower extremity muscle strengths, decreased cardiorespiratory fitness, and lower peak and reserve heart rates compared to normal-weight women. After follow-up, both groups improved their upper (32.9% and 41.5% in normal-weight and overweight/obese women, respectively) and lower extremity(49.5% and 47.8% in normal-weight and overweight/obese women, respectively) muscle strength. However, only normal-weight women improved their cardiorespiratory fitness (6.6%) and recovery heart rate (5 bpm). Resting, reserve and peak heart rates did not change in either group. CONCLUSIONS: Overweight/obese women displayed impaired heart rate response to exercise. Both groups improved muscle strength...

## Association between sarcopenia-related phenotypes and aerobic capacity indexes of older women

Oliveira, Ricardo Jacó de; Bottaro, Martim; Mota, Antonio Marco; Pitanga, Francisco; Guido, Marcelo; Leite, Tailce Kaley Moura; Bezerra, Lídia Mara Aguiar; Lima, Ricardo Moreno
Tipo: Artigo de Revista Científica Formato: Texto
EN
Relevância na Pesquisa
36.27%
The purpose of the present study was to examine the association between fat-free mass (FFM), quadriceps strength and sarcopenia with aerobic fitness indexes of elderly women. A total of 189 volunteers (66.7 ± 5.46 years) underwent aerobic capacity measurement through a symptom-limited cardiopulmonary exercise test to determine their individual ventilatory thresholds (VT) and peak oxygen uptake (VO2 peak). Quadriceps muscle strength was assessed using an isokinetic dynamometer. Also, dual energy X-ray absorptiometry was used to assess FFM and cutoff values were used to classify subjects as sarcopenic or nonsarcopenic. Correlations, student t-test and analysis of variance were used to examine the data. Both FFM and quadriceps strength variables were positively and significantly correlated with the measured aerobic capacity indexes. These results were observed for peak exercise as well as for ventilatory thresholds. Individuals classified as sarcopenic presented significantly lower muscle strength and (VO2 peak) when compared to nonsarcopenic. It can be concluded that FFM and quadriceps strength are significantly related to aerobic capacity indexes in older women, and that besides presenting lower quadriceps strength, women classified as sarcopenic have lower peak oxygen consumption. Taken together...

## Quasispecies evolution on a fitness landscape with a fluctuating peak

Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.25%
A quasispecies evolving on a fitness landscape with a single peak of fluctuating height is studied. In the approximation that back mutations can be ignored, the rate equations can be solved analytically. It is shown that the error threshold on this class of dynamic landscapes is defined by the time average of the selection pressure. In the case of a periodically fluctuating fitness peak we also study the phase-shift and response amplitude of the previously documented low-pass filter effect. The special case of a small harmonic fluctuation is treated analytically.; Comment: 5 pages, 5 figures

## Complexity of evolutionary equilibria in static fitness landscapes

Kaznatcheev, Artem
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.42%
A fitness landscape is a genetic space -- with two genotypes adjacent if they differ in a single locus -- and a fitness function. Evolutionary dynamics produce a flow on this landscape from lower fitness to higher; reaching equilibrium only if a local fitness peak is found. I use computational complexity to question the common assumption that evolution on static fitness landscapes can quickly reach a local fitness peak. I do this by showing that the popular NK model of rugged fitness landscapes is PLS-complete for K >= 2; the reduction from Weighted 2SAT is a bijection on adaptive walks, so there are NK fitness landscapes where every adaptive path from some vertices is of exponential length. Alternatively -- under the standard complexity theoretic assumption that there are problems in PLS not solvable in polynomial time -- this means that there are no evolutionary dynamics (known, or to be discovered, and not necessarily following adaptive paths) that can converge to a local fitness peak on all NK landscapes with K = 2. Applying results from the analysis of simplex algorithms, I show that there exist single-peaked landscapes with no reciprocal sign epistasis where the expected length of an adaptive path following strong selection weak mutation dynamics is $e^{O(n^{1/3})}$ even though an adaptive path to the optimum of length less than n is available from every vertex. The technical results are written to be accessible to mathematical biologists without a computer science background...

## Equilibrium Distribution of Mutators in the Single Fitness Peak Model

Tannenbaum, Emmanuel; Deeds, Eric; Shakhnovich, Eugene I.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.09%
This paper develops an analytically tractable model for determining the equilibrium distribution of mismatch repair deficient strains in unicellular populations. The approach is based on the single fitness peak (SFP) model, which has been used in Eigen's quasispecies equations in order to understand various aspects of evolutionary dynamics. As with the quasispecies model, our model for mutator-nonmutator equilibrium undergoes a phase transition in the limit of infinite sequence length. This "repair catastrophe" occurs at a critical repair error probability of $\epsilon_r = L_{via}/L$, where $L_{via}$ denotes the length of the genome controlling viability, while $L$ denotes the overall length of the genome. The repair catastrophe therefore occurs when the repair error probability exceeds the fraction of deleterious mutations. Our model also gives a quantitative estimate for the equilibrium fraction of mutators in {\it Escherichia coli}.; Comment: 4 pages, 2 figures (included as separate PS files)

## Critical properties of complex fitness landscapes

Østman, Bjørn; Hintze, Arend; Adami, Christoph
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.38%
Evolutionary adaptation is the process that increases the fit of a population to the fitness landscape it inhabits. As a consequence, evolutionary dynamics is shaped, constrained, and channeled, by that fitness landscape. Much work has been expended to understand the evolutionary dynamics of adapting populations, but much less is known about the structure of the landscapes. Here, we study the global and local structure of complex fitness landscapes of interacting loci that describe protein folds or sets of interacting genes forming pathways or modules. We find that in these landscapes, high peaks are more likely to be found near other high peaks, corroborating Kauffman's "Massif Central" hypothesis. We study the clusters of peaks as a function of the ruggedness of the landscape and find that this clustering allows peaks to form interconnected networks. These networks undergo a percolation phase transition as a function of minimum peak height, which indicates that evolutionary trajectories that take no more than two mutations to shift from peak to peak can span the entire genetic space. These networks have implications for evolution in rugged landscapes, allowing adaptation to proceed after a local fitness peak has been ascended.; Comment: 7 pages...

## Length of adaptive walk on uncorrelated and correlated fitness landscapes

Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.21%
We consider the adaptation dynamics of an asexual population that walks uphill on a rugged fitness landscape which is endowed with large number of local fitness peaks. We work in a parameter regime where only those mutants that are single mutation away are accessible, as a result of which the population eventually gets trapped at a local fitness maximum and the adaptive walk terminates. We study how the number of adaptive steps taken by the population before reaching a local fitness peak depends on the initial fitness of the population, the extreme value distribution of the beneficial mutations and correlations amongst the fitnesses. Assuming that the relative fitness difference between successive steps is small, we analytically calculate the average walk length for both uncorrelated and correlated fitnesses in all extreme value domains for a given initial fitness. We present numerical results for the model where the fitness differences can be large, and find that the walk length behavior differs from that in the former model in the Fr\'echet domain of extreme value theory. We also discuss the relevance of our results to microbial experiments.; Comment: To appear in Phys. Rev. E

## The pace of evolution across fitness valleys

Gokhale, Chaitanya S.; Iwasa, Yoh; Nowak, Martin A.; Traulsen, Arne
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.32%
How fast does a population evolve from one fitness peak to another? We study the dynamics of evolving, asexually reproducing populations in which a certain number of mutations jointly confer a fitness advantage. We consider the time until a population has evolved from one fitness peak to another one with a higher fitness. The order of mutations can either be fixed or random. If the order of mutations is fixed, then the population follows a metaphorical ridge, a single path. If the order of mutations is arbitrary, then there are many ways to evolve to the higher fitness state. We address the time required for fixation in such scenarios and study how it is affected by the order of mutations, the population size, the fitness values and the mutation rate.

## Adaptive walks and distribution of beneficial fitness effects

Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.22%
We study the adaptation dynamics of a maladapted asexual population on rugged fitness landscapes with many local fitness peaks. The distribution of beneficial fitness effects is assumed to belong to one of the three extreme value domains, viz. Weibull, Gumbel and Fr{\'e}chet. We work in the strong selection-weak mutation regime in which beneficial mutations fix sequentially, and the population performs an uphill walk on the fitness landscape until a local fitness peak is reached. A striking prediction of our analysis is that the fitness difference between successive steps follows a pattern of diminishing returns in the Weibull domain and accelerating returns in the Fr{\'e}chet domain, as the initial fitness of the population is increased. These trends are found to be robust with respect to fitness correlations. We believe that this result can be exploited in experiments to determine the extreme value domain of the distribution of beneficial fitness effects. Our work here differs significantly from the previous ones that assume the selection coefficient to be small. On taking large effect mutations into account, we find that the length of the walk shows different qualitative trends from those derived using small selection coefficient approximation.; Comment: Accepted in Evolution

## Evolution of clonal populations approaching a fitness peak

Gordo, I.; Campos, P. R. A.
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.3%
Populations facing novel environments are expected to evolve through the accumulation of adaptive substitutions. The dynamics of adaptation depend on the fitness landscape and possibly on the genetic background on which new mutations arise. Here, we model the dynamics of adaptive evolution at the phenotypic and genotypic levels, focusing on a Fisherian landscape characterized by a single peak. We find that Fisher's geometrical model of adaptation, extended to allow for small random environmental variations, is able to explain several features made recently in experimentally evolved populations. Consistent with data on populations evolving under controlled conditions, the model predicts that mean population fitness increases rapidly when populations face novel environments and then achieves a dynamic plateau, the rate of molecular evolution is remarkably constant over long periods of evolution, mutators are expected to invade and patterns of epistasis vary along the adaptive walk. Negative epistasis is expected in the initial steps of adaptation but not at later steps, a prediction that remains to be tested. Furthermore, populations are expected to exhibit high levels of phenotypic diversity at all times during their evolution. This implies that populations are possibly able to adapt rapidly to novel abiotic environments.; CAPES-IGC.

## Relação entre aptidão aeróbia e capacidade de sprints repetidos no futebol: efeito do protocolo. DOI: 10.5007/1980-0037.2011v13n2p111; Relationship between aerobic fitness and repeated sprint ability in soccer: protocol effect. DOI: 10.5007/1980-0037.2011v13n2p111

Silva, Juliano Fernandes da; Universidade Federal de Santa Catarina (UFSC). Florianópolis. SC.; Guglielmo, Luiz Guilherme Antonacci; Universidade Federal de Santa Catarina (UFSC). Florianópolis. SC.; Dittrich, Naiandra; Universidade Federal de Santa Cat
Fonte: Universidade Federal de Santa Catarina. Florianópolis, SC. Brasil Publicador: Universidade Federal de Santa Catarina. Florianópolis, SC. Brasil
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; "Avaliado por Pares",; Correlation methods; Avaliado por Pares; Correlacional Formato: application/pdf; application/pdf