Search results for "skeletal muscle"
showing 10 items of 430 documents
The effect of hormone replacement therapy and/or exercise on skeletal muscle attenuation in postmenopausal women: a yearlong intervention
2005
Hormone replacement therapy (HRT) has been reported to exert a positive effect on preserving muscle strength following the menopause, however, the mechanism of action remains unclear. We examined whether the mechanism involved preservation of muscle composition as determined by skeletal muscle attenuation. Eighty women aged 50-57 years were randomly assigned to either: HRT, exercise (Ex), HRT + exercise (ExHRT), and control (Co) for 1 year. The study was double-blinded with subjects receiving oestradiol and norethisterone acetate (Kliogest) or placebo. Exercise included progressive high-impact training for the lower limbs. Skeletal muscle attenuation in Hounsfield units (HU) was determined …
Muscle Free Fatty-Acid Uptake Associates to Mechanical Efficiency During Exercise in Humans
2018
Intrinsic factors related to muscle metabolism may explain the differences in mechanical efficiency (ME) during exercise. Therefore, this study aimed to investigate the relationship between muscle metabolism and ME. Totally 17 healthy recreationally active male participants were recruited and divided into efficient (EF; n = 8) and inefficient (IE; n = 9) groups, which were matched for age (mean ± SD 24 ± 2 vs. 23 ± 2 years), BMI (23 ± 1 vs. 23 ± 2 kg m−2), physical activity levels (3.4 ± 1.0 vs. 4.1 ± 1.0 sessions/week), and V˙O2peak (53 ± 3 vs. 52 ± 3 mL kg−1 min−1), respectively, but differed for ME at 45% of V˙O2peak intensity during submaximal bicycle ergometer test (EF 20.5 ± 3.5 vs. I…
Effects of hormone replacement therapy and high-impact physical exercise on skeletal muscle in post-menopausal women: a randomized placebo-controlled…
2001
An age-related decline in muscle performance is a known risk factor for falling, fracture and disability. In women, a clear deterioration is observed from early menopause. The effect of hormone replacement therapy (HRT) in preserving muscle performance is, however, unclear. This trial examined the effects of a 12-month HRT and high-impact physical exercise regimen on skeletal muscle in women in early menopause. A total of 80 women aged 50–57 years were assigned randomly to one of four groups: exercise (Ex), HRT, exercise+HRT (ExHRT) and control (Co). The exercise groups participated in a high-impact training programme. The administration of HRT (oestradiol/noretisterone acetate) or placebo …
Effects of high-fat diet and physical activity on pyruvate dehydrogenase kinase-4 in mouse skeletal muscle
2012
Abstract Background The expression of PDK4 is elevated by diabetes, fasting and other conditions associated with the switch from the utilization of glucose to fatty acids as an energy source. It is previously shown that peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a master regulator of energy metabolism, coactivates in cell lines pyruvate dehydrogenase kinase-4 (PDK4) gene expression via the estrogen-related receptor α (ERRα). We investigated the effects of long-term high-fat diet and physical activity on the expression of PDK4, PGC-1α and ERRα and the amount and function of mitochondria in skeletal muscle. Methods Insulin resistance was induced by a high-fat (HF) d…
Gelatinases and physical exercise: A systematic review of evidence from human studies
2017
Background Matrix metalloproteinases (MMPs), particularly gelatinase A (MMP-2) and gelatinase B (MMP-9), as well as their tissue inhibitors (TIMP-1 and TIMP-2), are involved in the development of skeletal muscle tissue, in the repair process after muscle injury and in the adaptive modifications induced by physical exercise in skeletal muscle. This paper aims at reviewing results from human studies that investigated the role of gelatinases and their inhibitors in skeletal muscle response to acute physical exercise or training. Methods Electronic databases PubMed/MEDLINE, Scopus and Web of Science were searched for papers published between January 2000 and February 2017. The papers were eligi…
Reduced Neck Muscle Strength and Altered Muscle Mechanical Properties in Cervical Dystonia Following Botulinum Neurotoxin Injections : A Prospective …
2016
Cervical dystonia (CD) is a focal dystonia causing involuntary activation of neck and shoulder muscles resulting in abnormal, sustained and painful posturing that may lead to physical disability and social withdrawal [1]. In recent years, botulinum neurotoxin (BoNT) has become the first line therapy for CD [2]. A subjective feeling of neck weakness has been reported as one of the most common localized adverse events of BoNT [2-7]. In clinical practice, this may sometimes be reported as having difficulty keeping the head upright. Although the effects of BoNT have been widely studied [2,5], there have been no prospective studies quantifying changes in maximal isometric neck muscle strength. O…
Acute exercise induced changes in rat skeletal muscle mRNAs and proteins regulating type IV collagen content
2001
This experiment tested the hypothesis that running-induced damage to rat skeletal muscle causes changes in synthesis and degradation of basement membrane type IV collagen and to proteins regulating its degradation. Samples from soleus muscle and red and white parts of quadriceps femoris muscle (MQF) were collected 6 h or 1, 2, 4, or 7 days after downhill running. Increased muscle β-glucuronidase activity indicated greater muscle damage in the red part of MQF than in the white part of MQF or soleus. In the red part of MQF, type IV collagen expression was upregulated at the pretranslational level and the protein concentration decreased, whereas matrix metalloproteinase-2 (MMP-2), a protein th…
Quantitative ultrasonography of muscle: Detection of adaptations to training in elderly women
1996
Abstract Objective: To develop quantitative ultrasonography in studying the adaptation of quadriceps muscle mass and composition to short-term physical training and rehabilitation in elderly women. Design: Randomized control trial. Setting: Measurements in a research laboratory and training in a fitness center and sports hall. Participants: Forty-two women, aged 76 to 78 years, with no indications against intensive physical exercise, randomly assigned to strength ( n = 16), endurance ( n = 15), and control ( n = 11) groups. Twelve subjects from the strength, 12 from the endurance, and 11 from the control group completed the study. Intervention: Supervised physical training 3 times a week fo…
SFRR-E Young Investigator AwardeeαB-crystallin modulation after acute exercise in skeletal muscle: the role of oxidative stress and fiber composition.
2015
αB-crystallin (CRYAB) is a member of the small heat shock proteins implicated in various biological functions, particularly in skeletal muscle where it is involved in adaptive remodelling processes, activation of gene transcription and stabilization of nascent proteins.In this research we analysed αB-crystallin' response in mouse gastrocnemius at 15' and 30' of recovery from an acute aerobic exercise (1hour), correlating its modulation with oxidative stress level and fiber composition, red (RG) and white gastrocnemius (WG).We found for the first time that the acute exercise lead to a short term, specific increase of phospho-αB-crystallin level (pCRYAB) in the RG, while no changes were obser…
PGC-1 isoforms and their target genes are expressed differently in human skeletal muscle following resistance and endurance exercise
2015
The primary aim of the present study was to investigate the acute gene expression responses of PGC-1 isoforms and PGC-1a target genes related to mitochondrial biogenesis (cytochrome C), angiogenesis (VEGF-A), and muscle hypertrophy (myostatin), after a resistance or endurance exercise bout. In addition, the study aimed to elucidate whether the expression changes of studied transcripts were linked to phosphorylation of AMPK and MAPK p38. Nineteen physically active men were divided into resistance exercise (RE, n = 11) and endurance exercise (EE, n = 8) groups. RE group performed leg press exercise (10 9 10 RM, 50 min) and EE walked on a treadmill (~80% HRmax, 50 min). Muscle biopsies were ob…