Effects of lower limb unloading on skeletal muscle mass and function in humans

1991 ◽  
Vol 70 (4) ◽  
pp. 1882-1885 ◽  
Author(s):  
H. E. Berg ◽  
G. A. Dudley ◽  
T. Haggmark ◽  
H. Ohlsen ◽  
P. A. Tesch
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Lower Limb ◽  
Skeletal Muscle Mass ◽  
Bed Rest ◽  
Experimental Period ◽  
Peak Torque ◽  
Human Model ◽  
Cross Sectional ◽  
And Function

A model to simulate effects of microgravity on skeletal muscle mass and function in humans has been developed. Unilateral lower limb unloading that allowed ankle, knee, and hip joint mobility was conducted in six healthy men by suspending one lower limb and having the subjects walk on crutches. They performed maximal unilateral concentric or eccentric quadriceps actions at different angular velocities before and after 4 wk of suspension and after 4 days and after 7 wk of uncontrolled recovery. Peak torque (PT) and angle-specific torque (AST) were measured. Muscle cross-sectional area (CSA) and radiological density (RD) of the thigh were assessed by means of computerized tomography. Concentric and eccentric PT and AST across speeds decreased (P less than 0.05) by 22 and 16%, respectively, in response to unloading. At 4 days of recovery PT (-11%) and AST (-7%) were still lower (P less than 0.05) than before. Muscle CSA and RD decreased (P less than 0.05) by 7 and 6%, respectively. After 7 wk of recovery PT, AST, CSA, and RD had returned to normal. The control limb showed no changes over the experimental period except for a 6% decrease (P less than 0.05) in RD. It is suggested that this human model of unloading could serve to simulate effects of microgravity on skeletal muscle mass and function because reductions in muscle mass and strength were of similar magnitude to those produced by bed rest.

Skeletal Muscle Mass Regulation in Critical Illness

2014 ◽  
Author(s):  
Zudin Puthucheary ◽  
Hugh Montgomery ◽  
Nicholas Hart ◽  
Stephen Harridge
Keyword(s):  
Skeletal Muscle ◽  
Critical Illness ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Bed Rest ◽  
Protein Homeostasis ◽  
Highly Sensitive ◽  
And Function ◽  
Inadequate Nutrition

Muscle is a dynamic, plastic, and malleable tissue that is highly sensitive to mechanical and metabolic signals. Muscle mass is regulated by protein homeostasis, with protein being continually turned over, reflecting a balance between synthesis and breakdown. This chapter discusses the effect of critical illness on skeletal muscle mass, protein homeostasis, and the intracellular signalling driving anabolism and catabolism. The focus will be on the unique challenges to which the skeletal muscle are exposed, such as inflammation, sepsis, sedation, and inadequate nutrition, which, in combination with the disuse signals of immobilization and bed rest, engender dramatic changes in muscle structure and function. The mechanisms regulating muscle loss during critical illness are being unravelled, but many questions remain unanswered. Detailed understanding of these mechanisms will help drive strategies to minimize or prevent intensive care-acquired muscle weakness and the long-term consequences experienced by ICU survivors.

scholarly journals Relationship between strength and muscle mass in middle-aged and elderly women: a cross-sectional study

2017 ◽  
Vol 20 (5) ◽  
pp. 660-669 ◽  
Author(s):  
Carine Fernandes de Souza ◽  
Mariana Carmem Apolinário Vieira ◽  
Rafaela Andrade do Nascimento ◽  
Mayle Andrade Moreira ◽  
Saionara Maria Aires da Câmara ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Lower Limb ◽  
Skeletal Muscle Mass ◽  
Elderly Women ◽  
Handgrip Strength ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Middle Aged ◽  
Cross Sectional

Abstract Objective: to analyze the relationship between handgrip strength and lower limb strength and the amount of segmental skeletal muscle mass in middle-aged and elderly women. Methods: an observational, cross-sectional, observational study of 540 women aged between 40 and 80 years in the cities of Parnamirim and Santa Cruz, Rio Grande do Norte, was performed. Sociodemographic data, anthropometric measurements, handgrip dynamometry, knee flexors and extensors of the dominant limbs, as well as the segmental muscle mass of the limbs were evaluated. Data were analyzed using Student's t-Test, Chi-square test, Effect Size and Pearson's Correlation (CI 95%). Results: there were statistically significant weak and moderate correlations between handgrip strength and upper limb muscle mass, knee flexion strength and lower limb muscle mass, and between knee extension strength and lower limb muscle mass for the age groups 40-59 years and 60 years or more (p<0.05). Conclusions: muscle strength correlates with skeletal muscle mass. It could therefore be an indicator of the decrease in strength. It is not the only such indicator, however, as correlations were weak and moderate, which suggests the need for more studies on this theme to elucidate which components may also influence the loss of strength with aging.

scholarly journals Body composition and energy intake — skeletal muscle mass is the strongest predictor of food intake in obese adolescents: The HEARTY trial

2016 ◽  
Vol 41 (6) ◽  
pp. 611-617 ◽  
Author(s):  
Jameason D. Cameron ◽  
Ronald J. Sigal ◽  
Glen P. Kenny ◽  
Angela S. Alberga ◽  
Denis Prud’homme ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Composition ◽  
Body Weight ◽  
Muscle Mass ◽  
Energy Intake ◽  
Skeletal Muscle Mass ◽  
Fat Free Mass ◽  
Cross Sectional ◽  
Percentage Body Fat ◽  
Obese Adolescents

There has been renewed interest in examining the relationship between specific components of energy expenditure and the overall influence on energy intake (EI). The purpose of this cross-sectional analysis was to determine the strongest metabolic and anthropometric predictors of EI. It was hypothesized that resting metabolic rate (RMR) and skeletal muscle mass would be the strongest predictors of EI in a sample of overweight and obese adolescents. 304 post-pubertal adolescents (91 boys, 213 girls) aged 16.1 (±1.4) years with body mass index at or above the 95th percentile for age and sex OR at or above the 85th percentile plus an additional diabetes risk factor were measured for body weight, RMR (kcal/day) by indirect calorimetry, body composition by magnetic resonance imaging (fat free mass (FFM), skeletal muscle mass, fat mass (FM), and percentage body fat), and EI (kcal/day) using 3 day food records. Body weight, RMR, FFM, skeletal muscle mass, and FM were all significantly correlated with EI (p < 0.005). After adjusting the model for age, sex, height, and physical activity, only FFM (β = 21.9, p = 0.007) and skeletal muscle mass (β = 25.8, p = 0.02) remained as significant predictors of EI. FFM and skeletal muscle mass also predicted dietary protein and fat intake (p < 0.05), but not carbohydrate intake. In conclusion, with skeletal muscle mass being the best predictor of EI, our results support the hypothesis that the magnitude of the body’s lean tissue is related to absolute levels of EI in a sample of inactive adolescents with obesity.

scholarly journals Cutoff values for appendicular skeletal muscle mass and strength in relation to fear of falling among Brazilian older adults: cross-sectional study

2017 ◽  
Vol 135 (5) ◽  
pp. 434-443 ◽  
Author(s):  
Ricardo Aurélio Carvalho Sampaio ◽  
Priscila Yukari Sewo Sampaio ◽  
Luz Albany Arcila Castaño ◽  
João Francisco Barbieri ◽  
Hélio José Coelho Júnior ◽  
...  
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Fear Of Falling ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Appendicular Skeletal Muscle ◽  
Appendicular Skeletal Muscle Mass

scholarly journals Relation of serum 25-hydroxyvitamin D status with skeletal muscle mass by sex and age group among Korean adults

2015 ◽  
Vol 114 (11) ◽  
pp. 1838-1844 ◽  
Author(s):  
Min Jung Ko ◽  
Sungha Yun ◽  
Kyungwon Oh ◽  
Kirang Kim
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Age Groups ◽  
Mean Value ◽  
High Serum ◽  
Cross Sectional ◽  
Mean Values ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D

AbstractThe objective of this study was to examine whether high serum 25-hydroxyvitamin D (25(OH)D) concentration was associated with high skeletal muscle mass, taking into account the effects of sex and age among the participants of the Korea National Health and Nutrition Examination Survey (KNHANES) aged 40 years or older. This was a cross-sectional study using data from the 2009 to 2010 KNHANES; a total of 8406 subjects (3671 men and 4735 women) were included. The appendicular skeletal muscle mass index (ASMMI, kg/m2) was estimated to measure the skeletal muscle mass. Hypovitaminosis was classified when the level of serum 25(OH)D was <20 ng/ml. The general linear model adjusted for confounding factors was used to determine differences in means of ASMMI by 25(OH)D status. The mean values of ASMMI were higher for men when compared with women. Women had a greater proportion of hypovitaminosis (71·1 %) compared with men (53·2 %). After adjusting for multiple factors, men were seen to have significant differences in ASMMI based on 25(OH)D status regardless of age, showing a lower mean value of ASSMI in those with hypovitaminosis. However, there was no difference in ASMMI by 25(OH)D status among women in both younger and older age groups. In conclusion, we found that there might be a positive relationship between 25(OH)D and skeletal muscle mass in men, indicating that interventions to improve 25(OH)D levels that are aimed at increasing muscle mass could be beneficial for men with more rapid decreased rate of skeletal muscle mass.

scholarly journals Alternate Mediterranean diet score is positively associated with skeletal muscle mass index in middle-aged adults

2017 ◽  
Vol 117 (8) ◽  
pp. 1181-1188 ◽  
Author(s):  
Hui-yuan Tian ◽  
Rui Qiu ◽  
Li-peng Jing ◽  
Zhan-yong Chen ◽  
Geng-dong Chen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mediterranean Diet ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
General Information ◽  
Whole Body ◽  
Cross Sectional ◽  
Mediterranean Diet Score ◽  
Skeletal Muscle Mass Index ◽  
Diet Score

AbstractResearches have suggested Mediterranean diet might lower the risk of chronic diseases, but data on skeletal muscle mass (SMM) are limited. This community-based cross-sectional study examined the association between the alternate Mediterranean diet score (aMDS) and SMM in 2230 females and 1059 males aged 40–75 years in Guangzhou, China. General information and habitual dietary information were assessed in face-to-face interviews conducted during 2008–2010 and 3 years later. The aMDS was calculated by summing the dichotomous points for the items of higher intakes of whole grain, vegetables, fruits, legumes, nuts, fish and ratio of MUFA:SFA, lower red meat and moderate ethanol consumption. The SMM of the whole body, limbs, arms and legs were measured using dual-energy X-ray absorptiometry during 2011–2013. After adjusting for potential covariates, higher aMDS was positively associated with skeletal muscle mass index (SMI, SMM/height2, kg/m2) at all of the studied sites in males (all Ptrend<0·05). The multiple covariate-adjusted SMI means were 2·70 % (whole body), 2·65 % (limbs), 2·50 % (arms) and 2·70 % (legs) higher in the high (v. low) category aMDS in males (all P<0·05). In females, the corresponding values were 1·35 % (Ptrend=0·03), 1·05, 0·52 and 1·20 %, (Ptrend>0·05). Age-stratified analyses showed that the favourable associations tended to be more pronounced in the younger subjects aged less than the medians of 59·2 and 62·2 years in females and males (Pinteraction>0·10). In conclusion, the aMDS shows protective associations with SMM in Chinese adults, particularly in male and younger subjects.

scholarly journals NEUROMUSCULAR CHANGES WITH AGING AND SARCOPENIA

2018 ◽  
pp. 1-3
Author(s):  
B.C. Clark
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Function ◽  
Skeletal Muscle Mass ◽  
The Past ◽  
Conceptual Definition ◽  
Age Related ◽  
Per Se ◽  
Definition Of ◽  
And Function

Sarcopenia was originally conceptualized as the age-related loss of skeletal muscle mass. Over the ensuing decades, the conceptual definition of sarcopenia has changed to represent a condition in older adults that is characterized by declining muscle mass and function, with “function” most commonly conceived as muscle weakness and/or impaired physical performance (e.g., slow gait speed). Findings over the past 15-years, however, have demonstrated that changes in grip and leg extensor strength are not primarily due to muscle atrophy per se, and that to a large extent, are reflective of declines in the integrity of the nervous system. This article briefly summarizes findings relating to the complex neuromuscular mechanisms that contribute to reductions in muscle function associated with advancing age, and the implications of these findings on the development of effective therapies.

scholarly journals Prevalence of Sarcopenia and Association with Lifestyle Patterns in Patients with Type 2 Diabetes Mellitus (P01-025-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Tatiana de Paula ◽  
Mauren de Freitas ◽  
Vanessa Lopes ◽  
Maria Elisa Miller ◽  
Karen Araujo ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Meta Analysis ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Logistic Regression Models ◽  
Type 2 Dm

Abstract Objectives The aim of the study was to establish the prevalence of sarcopenia and associated factors in elderly with type 2 diabetes (DM) in southern Brazil. Methods A cross-sectional study was performed in 240 patients with type 2 DM. The diagnosis of sarcopenia was performed according to EWGSOP criteria. Muscle mass was calculated by skeletal muscle mass index (appendicular skeletal muscle mass/height² - Inbody® bioimpendance). Muscle strength was assessed by manual grip strength (Jamar® dynamometer) and physical performance was assessed by the sit and lift test. Patients with type 2 DM with age ≥60 years and with the ability to ambulate were selected. Patients with recent cardiovascular events, serum creatinine >2.0 mg/dl, use of corticosteroids and BMI >40 kg/m² were excluded. The sample size was 240 patients based on meta-analysis who found 17% sarcopenia in elderly patients without DM. Results We included 240 patients aged 68.4 ± 5.5 years, 53.2% were women and the duration of DM was 15 (8–22) years, the BMI was 29.4 ± 4.4 kg/m². The prevalence of sarcopenia was 21% and men had more sarcopenia (75%). Patients with sarcopenia walk less [3541 (2227–4574) vs. 4521 (3037–5678) steps, P = 0.013], drink more alcohol [21 (56.8%) vs. 71 (31.8%); P < 0.034] and have lower total cholesterol levels [146 ± 41 Vs. 168 ± 43; P = 0.007] than the group without sarcopenia. In multivariate logistic regression models, walking < 3760 steps [OR = 2868; CI 95% 1.331–6.181] and male [OR = 5285; CI 95% 2261–12,350], were associated with sarcopenia. Conclusions The prevalence of sarcopenia was 21%, higher than in patients without diabetes (17%). In this group of patients, lower physical activity, and male sex were associated with sarcopenia. Funding Sources FIPE n. 160467; CAPES.

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