Effects of eccentric, concentric and eccentric/concentric training on muscle function and mass, functional performance, cardiometabolic health, quality of life and molecular adaptations of skeletal muscle in COPD patients: a multicentre randomised trial.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is the third cause of death worldwide. COPD is characterised by dyspnoea, limited exercise tolerance, and muscle dysfunction. Muscle dysfunction has been linked to dysregulation between muscle protein synthesis, myogenesis and degradation mechanisms. Conventional concentric cycling has been shown to improve several clinical outcomes and reduce muscle wasting in COPD patients. Eccentric cycling is a less explored exercise modality that allows higher training workloads imposing lower cardio-metabolic demand during exercise, which has shown to induce greater muscle mass and strength gains after training. Interestingly, the combination of eccentric and concentric cycling training has scarcely been explored. The molecular adaptations of skeletal muscle after exercise interventions in COPD have shown equivocal results. The mechanisms of muscle wasting in COPD and whether it can be reversed by exercise training are unclear. Therefore, this study aims two-fold: (1) to compare the effects of 12 weeks of eccentric (ECC), concentric (CONC), and combined eccentric/concentric (ECC/CONC) cycling training on muscle mass and function, cardiometabolic health, physical activity levels and quality of life in severe COPD patients; and (2) to examine the molecular adaptations regulating muscle growth after training, and whether they occur similarly in specific muscle fibres (i.e., I, IIa and IIx). METHODS: Study 1 will compare the effects of 12 weeks of CONC, ECC, versus ECC/CONC training on muscle mass and function, cardiometabolic health, levels of physical activity and quality of life of severe COPD patients using a multicentre randomised trial. Study 2 will investigate the effects of these training modalities on the molecular adaptations regulating muscle protein synthesis, myogenesis and muscle degradation in a subgroup of patients from Study 1. Changes in muscle fibres morphology, protein content, genes, and microRNA expression involved in skeletal muscle growth will be analysed in specific fibre-type pools. DISCUSSION: We aim to demonstrate that a combination of eccentric and concentric exercise could maximise the improvements in clinical outcomes and may be ideal for COPD patients. We also expect to unravel the molecular mechanisms underpinning muscle mass regulation after training in severe COPD patients. TRIAL REGISTRY: Deutshches Register Klinischer Studien; Trial registration: DRKS00027331; Date of registration: 12 January 2022. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00027331 .

Physiological response to eccentric and concentric cycling in patients with chronic obstructive pulmonary disease.

We aimed to compare the cardiorespiratory, metabolic, and perceptual responses to high- and moderate-intensity eccentric cycling versus moderate-intensity concentric cycling in chronic obstructive pulmonary disease (COPD) patients. Ten patients with moderate COPD (forced expiratory volume in 1 s (FEV1) = 68.6% ± 20.4% of predicted; 68.3 ± 9.1 years) performed 30 min of moderate-intensity concentric (CONC-M: 50% maximum workload; Wmax), moderate-intensity eccentric (ECC-M: 50% Wmax), and high-intensity eccentric (ECC-H: 100% Wmax) cycling. Average power output, oxygen consumption (V̇O2), minute ventilation (VE), respiratory frequency (fR), oxygen saturation (SpO2), heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), rate of perceived exertion (RPE), and dyspnea were measured during cycling. Compared with CONC-M, lower V̇O2 (-52% ± 14%), VE (-47% ± 16%), fR (-21% ± 14%), HR (-14% ± 16%), SBP (-73% ± 54%), RPE (-36% ± 26%), and dyspnea (-41% ± 37%) were found during ECC-M. During ECC-H, a similar metabolic demand to CONC-M was found. However, average power output was 117% ± 79% higher during ECC-H. Eccentric cycling can be safely performed by COPD patients and induced lower cardiorespiratory, metabolic, and perceptual responses than concentric exercise when performed at the same workload. Novelty Moderate- and high-intensity eccentric cycling can be performed by COPD patients. Moderate-intensity eccentric cycling showed lower cardiorespiratory, metabolic, and perceptual demand than concentric cycling at the same workload in COPD patients. Even at double workload, eccentric cycling induces lower cardiorespiratory, metabolic, and perceptual demand than moderate-intensity concentric cycling.

Robert Musil frente a Ernst Mach / Robert Musil versus a Ernst Mach

Sobre las teorías de Mach (TD de R. Musil) rebate que la representación científica tienda a construir un claro y completo inventario de hechos. Pues Mach se ve obligado a presuponer relaciones constantes en la naturaleza; pero esta regularidad de los fenómenos implica que la ley es algo más que cierto «cuadro», que las meras dependencias que defiende están en un segundo plano y que una relación teórica en física es mucho más que una relación de orden. Su concepción de laeconomía científica como «adaptación natural» significa un monismo biológico opuesto a las dualidades propias de un empirista (AU)

On Mach’s Theories (DT of R. Musil) rejects that the scientific representation tends to build a clear and complete inventory of facts. Mach finds himself obliged to presuppose constant relationshipsin nature; but this regularity of phenomena implies that the law is something more than a «table», that its mere dependencies are pushed into the background, and that a theoretical relationship in Physics is much more than an order relationship. His conception of scientific economy as a «natural adaptation» implies a biological monism opposed to the characteristic dualities of an empiricist (AU)

Sobre las profesiones científico-técnicas en la Plaza Universal de Suárez de Figueroa / No disponible

El Renacimiento científico visto a través de Suárez de figueroa, Plaza universal de todas las ciencias y artes, 1615. Los primeros escenarios de la lucha intelectual entre tradición e innovació, que había comenzado en el siglo XV

The scietific Rennaissance throught the Suárez de Figueroa´s Plaza universal de todas ciencias y artes, 1615. the early stages of the intellectual battle between tradition and innovation which began in the 15th century