scholarly journals Moderate-intensity resistance exercise alters skeletal muscle molecular and cellular structure and function in inactive older adults with knee osteoarthritis

2017 ◽  
Vol 122 (4) ◽  
pp. 775-787 ◽  
Author(s):  
Mark S. Miller ◽  
Damien M. Callahan ◽  
Timothy W. Tourville ◽  
James R. Slauterbeck ◽  
Anna Kaplan ◽  
...  
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Resistance Training ◽  
Knee Osteoarthritis ◽  
Resistance Exercise ◽  
High Intensity ◽  
Structure And Function ◽  
Moderate Intensity ◽  
Men And Women ◽  
And Function

High-intensity resistance exercise (REX) training increases physical capacity, in part, by improving muscle cell size and function. Moderate-intensity REX, which is more feasible for many older adults with disease and/or disability, also increases physical function, but the mechanisms underlying such improvements are not understood. Therefore, we measured skeletal muscle structure and function from the molecular to the tissue level in response to 14 wk of moderate-intensity REX in physically inactive older adults with knee osteoarthritis ( n = 17; 70 ± 1 yr). Although REX training increased quadriceps muscle cross-sectional area (CSA), average single-fiber CSA was unchanged because of reciprocal changes in myosin heavy chain (MHC) I and IIA fibers. Intermyofibrillar mitochondrial content increased with training because of increases in mitochondrial size in men, but not women, with no changes in subsarcolemmal mitochondria in either sex. REX increased whole muscle contractile performance similarly in men and women. In contrast, adaptations in single-muscle fiber force production per CSA (i.e., tension) and contractile velocity varied between men and women in a fiber type-dependent manner, with adaptations being explained at the molecular level by differential changes in myosin-actin cross-bridge kinetics and mechanics and single-fiber MHC protein expression. Our results are notable compared with studies of high-intensity REX because they show that the effects of moderate-intensity REX in older adults on muscle fiber size/structure and myofilament function are absent or modest. Moreover, our data highlight unique sex-specific adaptations due to differential cellular and subcellular structural and functional changes.NEW & NOTEWORTHY Moderate-intensity resistance training causes sex-specific adaptations in skeletal muscle structure and function at the cellular and molecular levels in inactive older adult men and women with knee osteoarthritis. However, these responses were minimal compared with high-intensity resistance training. Thus adjuncts to moderate-intensity training need to be developed to correct underlying cellular and molecular structural and functional deficits that are at the root of impaired physical function in this mobility-limited population.

Resistance exercise induces region-specific adaptations in anterior pituitary gland structure and function in rats

2013 ◽  
Vol 115 (11) ◽  
pp. 1641-1647 ◽  
Author(s):  
William J. Kraemer ◽  
Shawn D. Flanagan ◽  
Jeff S. Volek ◽  
Bradley C. Nindl ◽  
Jakob L. Vingren ◽  
...  
Keyword(s):  
Resistance Training ◽  
Resistance Exercise ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Acute Exercise ◽  
Structure And Function ◽  
Anterior Pituitary Gland ◽  
Sprague Dawley ◽  
Gh Secretion ◽  
And Function

The anterior pituitary gland (AP) increases growth hormone (GH) secretion in response to resistance exercise (RE), but the nature of AP adaptations to RE is unknown. To that end, we examined the effects of RE on regional AP somatotroph GH release, structure, and relative quantity. Thirty-six Sprague-Dawley rats were assigned to one of four groups: 1) no training or acute exercise (NT-NEX); 2) no training with acute exercise (NT-EX); 3) resistance training without acute exercise (RT-NEX); 4) resistance training with acute exercise (RT-EX). RE incorporated 10, 1 m-weighted ladder climbs at an 85° angle. RT groups trained 3 days/wk for 7 wk, progressively. After death, trunk blood was collected, and each AP was divided into quadrants (ventral-dorsal and left-right). We measured: 1) trunk plasma GH; 2) somatotroph GH release; 3) somatotroph size; 4) somatotroph secretory content; and 5) percent of AP cells identified as somatotrophs. Trunk GH differed by group (NT-NEX, 8.9 ± 2.4 μg/l; RT-NEX, 9.2 ± 3.5 μg/l; NT-EX, 15.6 ± 3.4 μg/l; RT-EX, 23.4 ± 4.6 μg/l). RT-EX demonstrated greater somatotroph GH release than all other groups, predominantly in ventral regions ( P < 0.05-0.10). Ventral somatotrophs were larger in NT-EX and RT-NEX compared with RT-EX ( P < 0.05–0.10). RT-NEX exhibited significantly greater secretory granule content than all other groups but in the ventral-right region only ( P < 0.05–0.10). Our findings indicate reproducible patterns of spatially distinct, functionally different somatotroph subpopulations in the rat pituitary gland. RE training appears to induce dynamic adaptations in somatotroph structure and function.

scholarly journals Milk and resistance exercise intervention to improve muscle function in community-dwelling older adults at risk of sarcopenia (MIlkMAN): protocol for a pilot study

BMJ Open ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. e031048 ◽  
Author(s):  
Antoneta Granic ◽  
Christopher Hurst ◽  
Lorelle Dismore ◽  
Karen Davies ◽  
Emma Stevenson ◽  
...  
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
At Risk ◽  
Pilot Study ◽  
Resistance Exercise ◽  
Muscle Function ◽  
Community Dwelling ◽  
Skimmed Milk ◽  
And Function ◽  
Community Dwelling Older Adults

IntroductionSarcopenia is a progressive muscle disorder characterised by decline in skeletal muscle mass, strength and function leading to adverse health outcomes, including falls, frailty, poor quality of life and death. It occurs more commonly in older people and can be accelerated by poor diet and low physical activity. Intervention studies incorporating higher dietary protein intakes or protein supplementation combined with resistance exercise (RE) have been shown to limit muscle function decline. However, less is known about the role of whole foods in reducing the risk of sarcopenia. Milk is a source of high-quality nutrients, which may be beneficial for skeletal muscle. This pilot study examines the feasibility and acceptability of milk consumption with RE to improve muscle function in community-dwelling older adults at risk of sarcopenia.Methods and analysis30 older adults aged ≥65 years will be randomly allocated to three groups: ‘whole milk+RE’, ‘skimmed milk+RE’ or ‘control drink+RE’. Assessments will take place in participants’ homes, including screening (milk allergies, grip strength, walking speed), baseline and postintervention health and function. All participants will undertake a structured RE intervention twice a week for 6 weeks at a local gym, followed by the consumption of 500 mL of whole or skimmed milk (each ~20 g of protein) or an isocaloric control drink and another 500 mL at home. Participants’ views about the study will be assessed using standardised open-ended questions. The primary outcomes include feasibility and acceptability of the intervention with recruitment, retention and intervention response rates. Analyses will include descriptive statistics, exploration of qualitative themes and intervention fidelity.Ethics and disseminationOutputs include pilot data to support funding applications; public involvement events; presentation at conferences and peer-reviewed publication.Trial registration numberISRCTN13398279; Pre-results.

scholarly journals Skeletal muscle mitochondrial density, gene expression, and enzyme activities in human heart failure: minimal effects of the disease and resistance training

2012 ◽  
Vol 112 (11) ◽  
pp. 1864-1874 ◽  
Author(s):  
Michael J. Toth ◽  
Mark S. Miller ◽  
Kimberly A. Ward ◽  
Philip A. Ades
Keyword(s):  
Gene Expression ◽  
Heart Failure ◽  
Skeletal Muscle ◽  
Resistance Training ◽  
Transcriptional Regulators ◽  
Structure And Function ◽  
Resistance Exercise Training ◽  
Mitochondrial Structure ◽  
Muscle Disuse ◽  
And Function

Impaired skeletal muscle energetics could adversely affect physical and metabolic function in patients with heart failure (HF). The effect of HF on aspects of mitochondrial structure and function, independent of muscle disuse and other disease-related confounding factors, however, is unclear. Moreover, no study has evaluated whether resistance exercise training, a modality that increases functional capacity, might derive its benefits through modulation of mitochondrial structure and function. Thirteen HF patients and 14 age- and physical activity-matched controls were evaluated for skeletal muscle mitochondrial size/content, gene expression, and enzyme activity before and after an 18-wk resistance exercise-training program. At baseline, HF patients and controls had similar mitochondrial fractional areas, although HF patients had larger average mitochondrion size ( P < 0.05) and a trend toward a reduced number of mitochondria ( P ≤ 0.10). No differences in the expression of transcriptional regulators or cytochrome oxidase subunits or the activity of mitochondrial and cytosolic enzymes were noted. Relationships among transcriptional regulators suggested that networks controlling mitochondrial content and gene expression are intact. Resistance training increased ( P < 0.01) mitochondrial transcription factor A expression in patients and controls, and this increase was related to improvements in muscle strength ( P = 0.05). Training did not, however, alter mitochondrial size/content, enzyme activities, or expression of other transcriptional regulators. In conclusion, our results suggest that the HF syndrome has minimal effects on skeletal muscle mitochondrial biology when the confounding effects of muscle disuse and other disease-related factors are removed. Moreover, the beneficial effects of resistance training on physical function in HF patients and controls are likely not related to alterations in mitochondrial biology.

scholarly journals Resistance training alters skeletal muscle structure and function in human heart failure: effects at the tissue, cellular and molecular levels

2012 ◽  
Vol 590 (5) ◽  
pp. 1243-1259 ◽  
Author(s):  
Michael J. Toth ◽  
Mark S. Miller ◽  
Peter VanBuren ◽  
Nicholas G. Bedrin ◽  
Martin M. LeWinter ◽  
...  
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Resistance Training ◽  
Human Heart ◽  
Structure And Function ◽  
Human Heart Failure ◽  
Muscle Structure ◽  
And Function

scholarly journals Essential Role of Septin 7 in Skeletal Muscle Structure and Function

2020 ◽  
Vol 118 (3) ◽  
pp. 258a
Author(s):  
Laszlo Csernoch ◽  
Mónika Gönczi ◽  
Zsolt Ráduly ◽  
László Szabó ◽  
Nóra Dobrosi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Essential Role ◽  
Structure And Function ◽  
Muscle Structure ◽  
And Function

scholarly journals High intensity resistance training as intervention method to Knee Osteoarthritis

2021 ◽  
Author(s):  
Andrea Malorgio ◽  
Marta Malorgio ◽  
Matteo Benedetti ◽  
Simoen Casarosa ◽  
Roberto Cannataro
Keyword(s):  
Resistance Training ◽  
Knee Osteoarthritis ◽  
High Intensity ◽  
Intervention Method

PROLONGED INTRAVENOUS INFUSION OF LABELLED IODOCOMPOUNDS IN THE RAT: [125I]IODIDE METABOLISM AND EFFECTS OF MODERATE DIETARY IODINE DEFICIENCY

1979 ◽  
Vol 82 (2) ◽  
pp. 227-234 ◽  
Author(s):  
VIPA BOONNAMSIRI ◽  
J. C. KERMODE ◽  
B. D. THOMPSON
Keyword(s):  
Skeletal Muscle ◽  
Iodine Deficiency ◽  
Intravenous Infusion ◽  
Structure And Function ◽  
Continuous Intravenous Infusion ◽  
Close Approximation ◽  
Faecal Excretion ◽  
And Function ◽  
Layer Chromatography ◽  
Secretion Rates

SUMMARY Radio-iodide was administered by prolonged continuous intravenous infusion to rats maintained under iodine-replete conditions and in moderate iodine deficiency. A close approximation to equilibrium labelling was thereby achieved. Labelled iodocompounds extracted from various tissues were analysed by thin-layer chromatography. Moderate iodine deficiency resulted in a slight increase in the ratio of mono-iodotyrosine to di-iodotyrosine in the thyroid. No change in the ratio of tri-iodothyronine (T3) to thyroxine (T4) was found in thyroid, plasma or skeletal muscle. Faecal excretion of T3 declined appreciably relative to that of T4. Under iodine-replete conditions the ratio of thyroidal secretion rates of T3 and T4 was estimated to be more than three times higher than the ratio of these iodocompounds within the thyroid. Heterogeneity of thyroglobulin structure and function may explain these observations.

Sign in / Sign up

Export Citation Format

Share Document