Agreement between maximal lactate steady state and critical power in different sports. A systematic review and Bayesian meta-regression

Analysis codes of R software and dataset

Concordância da máxima fase estável de lactato sanguíneo com diferentes abordagens de determinação de limiares de intensidade de exercício: revisões sistemáticas com metaanálises bayesianas

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Desportos, Programa de Pós-Graduação em Educação Física, Florianópolis, 2023.Há pelo menos 50 anos, vários limiares de intensidade de exercício têm sido propostos. Desta forma, existem dezenas de métodos/abordagens determinados por diferentes testes, protocolos e medidas fisiológicas ou de performance física. A forma mais comum de validar a maioria destes limiares foi feita comparando-os a um ?limiar padrão-ouro?, que na maioria dos casos é a máxima fase estável de lactato sanguíneo (MFEL). Existe um grande volume de literatura, acompanhada de polêmica sobre a concordância desses limiares com a MFEL. É possível que os fatores que influenciam o nível de concordância devem-se as dependências dos protocolos dos testes e das características dos estudos e dos sujeitos incluídos nas amostras. Levando em consideração os dois últimos fatores, estudos de revisão sistemática com meta-análise de modelos de meta-regressão são interessantes para verificar os fatores que influenciam o nível de concordância dos diferentes limiares com a MFEL. Deste modo, a presente Tese teve como objetivo revisar a literatura cientifica por meio de métodos sistematizados e posteriormente aplicar as análises meta-analíticas para verificar as covariáveis que influenciam a magnitude da concordância entre os limiares de lactato (LL), potência crítica (PC) e o teste de lactato mínimo (LACM) com a MFEL. Foram realizadas 3 revisões sistemáticas independentes para verificar a concordância da MFEL com os LL, LACM e PC, respectivamente. Todos os métodos seguiram o protocolo do Preferred Reporting Items for Systematic Reviews and Meta-Analyses ? PRISMA. As buscas na literatura foram conduzidas nas bases de dados PubMed, ScienceDirect, Scielo e Google Scholar, utilizando palavras-chave relacionadas a MFEL. Para verificar a concordância dos métodos, dois tipos de tamanhos de efeitos foram utilizados: I) diferença média; e II) desvio padrão (DP) das diferenças, sendo ambos expressos em percentuais equivalentes à medida de potência. As meta-análises foram conduzidas utilizando modelos Bayesianos de meta-regressões multiníveis e multivariados para lidar com as diferentes fontes de dependência entre os dados. Todos os dados foram apresentados como distribuições posteriores com sua moda e intervalos de credibilidade de 90%, a heterogeneidade foi expressa como um desvio padrão (t) e foi ainda utilizado o Pseudo-R², que fornece uma estimativa de quanto a heterogeneidade foi contabilizada pelas covariáveis incluídas nos modelos. A partir das buscas na literatura e da seleção dos estudos, foram incluídos 79, 38 e 28 estudos para a comparação entre a MFEL e os LL, a PC e o LACM, respectivamente. Nas três meta-análises, as covariáveis com altas probabilidades (>90%) de alterar a diferença média foram: a modalidade de exercício, o intervalo de tempo das amostragens de sangue e o critério de delta da concentração de lactato sanguíneo, bem como o número e a duração das pausas da MFEL. Para a comparação entre LL e MFEL, as covariáveis influenciadoras foram a duração dos estágios do teste incremental, os métodos de identificação do LL e local de aquisição das amostras de sangue. Para a comparação entre MFEL e PC, as covariáveis da PC foram a duração da maior carga preditiva, o tipo de teste das cargas preditivas e o número de parâmetros da modelagem matemática. Já para o LACM as covariáveis foram a carga inicial e a duração dos estágios do teste incremental da Fase 3 do teste. Nas três meta-análises, as principais covariáveis com altas probabilidades de modificar a magnitude do DP das diferenças foram o consumo máximo de oxigênio e o sexo dos sujeitos e a modalidade de exercício. O Pseudo-R² entre MFEL e LL variou entre 47% e 91% para a diferença média e 33% para o DP das diferenças. Para a MFEL versus PC foi 84% e 59% e para a MFEL versus LACM 60% e 95% para diferença média e DP das diferenças, respectivamente. Os resultados demonstram que a comparação entre esses índices foi modulada por características inerentes aos protocolos de testes, ao modo de exercício e as características dos sujeitos como o sexo, idade e consumo máximo de oxigênio. Assim conclui-se que para a predição da MFEL esses fatores apresentados devem ser levados em consideração, a fim de se obter maior confiabilidade das estimativas.Abstract: For at least 50 years, several exercise intensity thresholds have been proposed. As a result, there are dozens of methods/approaches determined by different tests, protocols, and physiological or physical performance measurements. The most common way to validate most of these thresholds has been by comparing them to a 'gold standard threshold', which in most cases is the maximal lactate steady state (MLSS). There is a large volume of literature accompanied by controversy regarding the agreement of these thresholds with MLSS. It is possible that the factors influencing the level of agreement are due to the dependencies of the test protocols and the characteristics of the studies and subjects included in the samples. Taking into consideration these two factors, systematic review studies with meta-analysis of meta-regression models are interesting to verify the factors influencing the level of agreement between different thresholds and MLSS. Thus, the present thesis aimed to review the scientific literature through systematic methods and subsequently apply meta-analytic analyses to verify the covariates that influence the magnitude of agreement between lactate thresholds (LT), critical power (CP), and the lactate minimum test (LMT) with MLSS. Three independent systematic reviews were conducted to verify the agreement of MLSS with LT, LMT, and CP, respectively. All methods followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Literature searches were conducted in the PubMed, ScienceDirect, Scielo, and Google Scholar databases, using keywords related to MLSS. To assess the agreement of the methods, two types of effect sizes were used: I) mean difference, and II) standard deviation (SD) of the differences, both expressed as percentages equivalent to the power output measure. The meta-analyses were conducted using Bayesian multilevel and multivariate meta-regression models to deal with the different sources of dependence among the data. All data were presented as posterior distributions with their mode and 90% credibility intervals, heterogeneity was expressed as a standard deviation (t), and Pseudo-R² was also used, providing an estimate of how much heterogeneity was accounted for by the covariates included in the models. Based on the literature searches and study selection, 79, 38, and 28 studies were included for the comparison between MLSS and LT, CP and LMT, respectively. In all three meta-analyses, covariates with high probabilities (>90%) of altering the mean difference were: exercise modality, blood sampling time interval, criterion for delta blood lactate concentration, as well as the number and duration of MLSS breaks. For the comparison between LT and MLSS, the influential covariates were the duration of the stages of the incremental test, the LT identification methods, and the location of blood sample acquisition. For the comparison between MLSS and CP, the CP covariates were the duration of the highest predictive load, the type of predictive load test, and the number of parameters in the mathematical modeling. For LMT, the covariates were the initial load and the duration of the stages of the incremental test in Phase 3 of the test. In all three meta-analyses, the main covariates with high probabilities of modifying the magnitude of SD of the differences were maximal oxygen uptake, subject's sex, and exercise modality. The Pseudo-R² between MLSS and LT ranged from 47% to 91% for the mean difference and 33% for the SD of the differences. For MLSS versus CP, it was 84% and 59%, and for MLSS versus LMT, it was 60% and 95% for the mean difference and SD of the differences, respectively. The results demonstrate that the comparison between these indexes was modulated by characteristics inherent to the test protocols, exercise mode, and subject characteristics such as sex, age, and maximum oxygen consumption. Thus, it is concluded that for the prediction of MLSS, these factors should be taken into consideration to obtain more reliable estimates

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Chronic Adaptations to Eccentric Cycling Training: A Systematic Review and Meta-Analysis

This study aimed to investigate the effects of eccentric cycling (ECCCYC) training on performance, physiological, and morphological parameters in comparison to concentric cycling (CONCYC) training. Searches were conducted using PubMed, Embase, and ScienceDirect. Studies comparing the effect of ECCCYC and CONCYC training regimens on performance, physiological, and/or morphological parameters were included. Bayesian multilevel meta-analysis models were used to estimate the population’s mean difference between chronic responses from ECCCYC and CONCYC training protocols. Group levels and meta-regression were used to evaluate the specific effects of subjects and study characteristics. Fourteen studies were included in this review. The meta-analyses showed that ECCCYC training was more effective in increasing knee extensor strength, vastus lateralis fiber cross-sectional area, and six-minute walking distance compared to CONCYC. Moreover, ECCCYC was as effective as CONCYC in decreasing body fat percentage. CONCYC was more effective in increasing V˙O2max and peak power output attained during concentric incremental tests. However, group-level analyses revealed that ECCCYC was more effective than CONCYC in improving V˙O2max in patients with cardiopulmonary diseases. ECCCYC is a viable modality for exercise interventions aiming to improve parameters of muscle strength, hypertrophy, functional capacity, aerobic power, and body composition, with more advantages than CONCYC training in improving neuromuscular variables