Search results for " Muscle"
showing 10 items of 1495 documents
Power training and postmenopausal hormone therapy affect transcriptional control of specific co-regulated gene clusters in skeletal muscle
2010
At the moment, there is no clear molecular explanation for the steeper decline in muscle performance after menopause or the mechanisms of counteractive treatments. The goal of this genome-wide study was to identify the genes and gene clusters through which power training (PT) comprising jumping activities or estrogen containing hormone replacement therapy (HRT) may affect skeletal muscle properties after menopause. We used musculus vastus lateralis samples from early stage postmenopausal (50–57 years old) women participating in a yearlong randomized double-blind placebo-controlled trial with PT and HRT interventions. Using microarray platform with over 24,000 probes, we identified 665 diffe…
Neural Activation During Submaximal Contractions Seems More Reflective of Neuromuscular Ageing than Maximal Voluntary Activation
2016
International audience; This study aimed at testing the hypothesis that differences in neural activation strategy during submaximal but not maximal plantarflexions exist between young and older men. Eleven young men (YM, 26 +/- 4 years) and thirteen old men (OM, 76 +/- 3 years) volunteered for the investigation. Maximal voluntary torque (MVT) was 38.2%, lower (p < 0.001) in OM than in YM, while voluntary activation was equivalent (similar to 97%). The relationship between the interpolated twitch torque and the voluntary torque (IT-VT relationship) was composite (curvilinear + exponential) for both age-groups. However, the OM showed accentuated concavity, as attested by the occurrence of the…
Physical exercise as an epigenetic modulator: Eustress, the "positive stress" as an effector of gene expression.
2012
Physical exercise positively influences epigenetic mechanisms and improves health. Several issues remain unclear concerning the links between physical exercise and epigenetics. There is growing concern about the negative influence of excessive and persistent physical exercise on health. How an individual physically adapts to the prevailing environmental conditions might influence epigenetic mechanisms and modulate gene expression. In this article, we put forward the idea that physical exercise, especially long-term repetitive strenuous exercise, positively affects health, reduces the aging process, and decreases the incidence of cancer through induced stress and epigenetic mechanisms. We pr…
The involvement of ankle muscles in maintaining balance in the upright posture is higher in elderly fallers
2016
International audience; The purpose of this study was to determine whether the mechanical contribution of ankle muscles in the upright stance differed among young adults (YA) (n = 10, age: similar to 24.3), elderly non-fallers (ENF) (n = 12, age: similar to 77.3) and elderly fallers (EF) (n = 20, age: similar to 80.7). Torque and electromyographic (EMG) activity were recorded on the triceps surae and tibialis anterior during maximum and submaximum contractions in the seated position. EMG activity was also recorded in subjects standing still. Plantar flexor (PF) and dorsal flexor (DF) torques generated in the upright posture were estimated from the torque-EMG relationship obtained during sub…
Update on the ESCEO recommendation for the conduct of clinical trials for drugs aiming at the treatment of sarcopenia in older adults
2020
Abstract Background In 2016, an expert working group was convened under the auspices of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) and formulated consensus recommendations for the conduct of clinical trials for drugs to prevent or treat sarcopenia. Aims The objective of the current paper is to provide a 2020 update of the previous recommendations in accordance with the evidence that has become available since our original recommendations. Methods This paper is based on literature reviews performed by members of the ESCEO working group and followed up with face to face meetings organized for the whole group to make amendments and discuss…
The effect of resistance training programs on lean body mass in postmenopausal and elderly women: a meta-analysis of observational studies
2021
AbstractAging and menopause are associated with morphological and functional changes which may lead to loss of muscle mass and therefore quality of life. Resistance training (RT) is an effective training mode to increase muscle mass. We reviewed the existing literature to identify studies implementing RT protocols and evaluating muscle hypertrophy exclusively in healthy, postmenopausal and elderly women. Participants’ age range was comprised between 50 and 80 years. The primary outcome observed was muscle hypertrophy. Fat mass was also evaluated, if available. PubMed and Web of Science were the screened database, and original articles written in English and published from 2000 up to 2020 we…
Effects of fasting on skeletal muscles and body fat of adult and old C57BL/6J mice
2021
Fasting improves metabolic health, but is also associated with loss of lean body mass. We investigated if old mice are less resistant to fasting-induce muscle wasting than adult mice. We compared changes in skeletal muscles and fat distribution in C57BL/6J mice subjected to 48-hour fasting at adult (6-month old) or old (24-month old) age. Old mice lost less weight (11.9 ± 1.5 vs 16.9 ± 2.8%, p 0.001) and showed less (p 0.01) pronounced muscle wasting than adult mice. Extensor digitorum longus (EDL) muscle force decreased only in adult mice after fasting. Serum IGF-1 levels were higher (p 0.01) and showed greater (p 0.01) decline in adult mice compared to old mice. Phosphorylation of 4EB…
Effects of strength and endurance training on muscle fibrecharacteristics in elderly women
1997
The effects of 18 weeks' intensive strength and endurance training on fibre characteristics of the vastus lateralis muscle were studied in 76- to 78-year-old women. Type I and type IIa fibres constituted over 90% of the cell population and were almost equally represented. No changes were observed in the proportions of the different fibre types. When comparing the baseline and the 18-week measurements within the groups, the strength group showed a mean increase of 34% (P = 0.028) in mean type I fibre area. The frequency histograms showed an increased proportion of larger type I fibres after strength training and a decreased proportion of smaller type IIa fibres after endurance training. In t…
Influence of Duration of Experiment on Rate of Uptake of Radioactive Potassium in Smooth Muscle
1963
THE rates of uptake and loss of radioactive tracers by excitable tissues can often be described by a function involving one exponential term1–3, but over relatively long periods deviations have been observed from such a simple course4–7. The rates of exchange towards the end of such periods are commonly slower than would be predicted from the initial rates and two general causes for this behaviour have been suggested: either the rates are, in fact, diminishing during the course of an experiment or the tissue is not behaving uniformly. This latter possibility has been extensively investigated1,8–15, because biological material shows an obvious lack of uniformity, and because deviations from …
Associations Between Lipoprotein Subfractions and Area and Density of Abdominal Muscle and Intermuscular Adipose Tissue: The Multi-Ethnic Study of At…
2021
Skeletal muscle quantity and quality decrease with older age, which is partly attributed to ectopic fat infiltration and has negative metabolic consequences. To inform efforts to preserve skeletal muscle with aging, a better understanding of biologic correlates of quantity and quality of muscle and intermuscular adipose tissue (IMAT) is needed. We used targeted lipidomics of lipoprotein subfractions among 947 Multi-Ethnic Study of Atherosclerosis participants to provide a detailed metabolic characterization of area and density of abdominal muscle and IMAT. Serum lipoprotein subfractions were measured at the first visit using 1H-Nuclear Magnetic Resonance spectroscopy. Muscle and IMAT area (…