scholarly journals Human skeletal muscle metabolic economy in vivo: effects of contraction intensity, age, and mobility impairment

2014 ◽  
Vol 307 (9) ◽  
pp. R1124-R1135 ◽  
Author(s):  
Anita D. Christie ◽  
Anne Tonson ◽  
Ryan G. Larsen ◽  
Jacob P. DeBlois ◽  
Jane A. Kent
Keyword(s):  
Functional Mobility ◽  
Older Individuals ◽  
Mobility Impairment ◽  
Cross Sectional ◽  
Age Related ◽  
Creatine Kinase Reaction ◽  
Voluntary Contractions ◽  
In Vivo Effects ◽  
Muscle Cross Sectional Area

We tested the hypothesis that older muscle has greater metabolic economy (ME) in vivo than young, in a manner dependent, in part, on contraction intensity. Twenty young (Y; 24 ± 1 yr, 10 women), 18 older healthy (O; 73 ± 2, 9 women) and 9 older individuals with mild-to-moderate mobility impairment (OI; 74 ± 1, 7 women) received stimulated twitches (2 Hz, 3 min) and performed nonfatiguing voluntary (20, 50, and 100% maximal; 12 s each) isometric dorsiflexion contractions. Torque-time integrals (TTI; Nm·s) were calculated and expressed relative to maximal fat-free muscle cross-sectional area (cm2), and torque variability during voluntary contractions was calculated as the coefficient of variation. Total ATP cost of contraction (mM) was determined from flux through the creatine kinase reaction, nonoxidative glycolysis and oxidative phosphorylation, and used to calculate ME (Nm·s·cm−2·mM ATP−1). While twitch torque relaxation was slower in O and OI compared with Y ( P ≤ 0.001), twitch TTI, ATP cost, and economy were similar across groups ( P ≥ 0.15), indicating comparable intrinsic muscle economy during electrically induced isometric contractions in vivo. During voluntary contractions, normalized TTI and total ATP cost did not differ significantly across groups ( P ≥ 0.20). However, ME was lower in OI than Y or O at 20% and 50% MVC ( P ≤ 0.02), and torque variability was greater in OI than Y or O at 20% MVC ( P ≤ 0.05). These results refute the hypothesis of greater muscle ME in old age, and provide support for lower ME in impaired older adults as a potential mechanism or consequence of age-related reductions in functional mobility.

Muscle fiber number in biceps brachii in bodybuilders and control subjects

1984 ◽  
Vol 57 (5) ◽  
pp. 1399-1403 ◽  
Author(s):  
J. D. MacDougall ◽  
D. G. Sale ◽  
S. E. Alway ◽  
J. R. Sutton
Keyword(s):  
Muscle Fiber ◽  
Biceps Brachii ◽  
Cross Sectional Area ◽  
Muscle Size ◽  
Sectional Area ◽  
Cross Sectional ◽  
Trained Subjects ◽  
Fiber Area ◽  
Muscle Cross Sectional Area

Muscle fiber numbers were estimated in vivo in biceps brachii in 5 elite male bodybuilders, 7 intermediate caliber bodybuilders, and 13 age-matched controls. Mean fiber area and collagen volume density were calculated from needle biopsies and muscle cross-sectional area by computerized tomographic scanning. Contralateral measurements in a subsample of seven subjects indicated the method for estimation of fiber numbers to have adequate reliability. There was a wide interindividual range for fiber numbers in biceps (172,085–418,884), but despite large differences in muscle size both bodybuilder groups possessed the same number of muscle fibers as the group of untrained controls. Although there was a high correlation between average cross-sectional fiber area and total muscle cross-sectional area within each group, many of the subjects with the largest muscles also tended to have a large number of fibers. Since there were equally well-trained subjects with fewer than normal fiber numbers, we interpret this finding to be due to genetic endowment rather than to training-induced hyperplasia. The proportion of muscle comprised of connective and other noncontractile tissue was the same for all subjects (approximately 13%), thus indicating greater absolute amounts of connective tissue in the trained subjects. We conclude that in humans, heavy resistance training directed toward achieving maximum size in skeletal muscle does not result in an increase in fiber numbers.

Biaxial Mechanical Testing of Single Annulus Fibrosus Layers

2010 ◽  
Author(s):  
J. P. Rys ◽  
A. M. Ellingson ◽  
D. J. Nuckley ◽  
V. H. Barocas
Keyword(s):  
Intervertebral Disc ◽  
Annulus Fibrosus ◽  
Spinal Nerve ◽  
Older Individuals ◽  
Physical Trauma ◽  
Age Related ◽  
Biaxial Mechanical Testing ◽  
Partial Displacement ◽  
Outer Annulus Fibrosus

The intervertebral disc (IVD), consisting of the inner nucleus pulposus and the outer annulus fibrosus, is subjected to multiaxial stress in vivo. The disc undergoes degenerative changes that account for impairment and disability in middle-aged and older individuals.4 In addition to age-related degeneration, the intervertebral disc is subject to the development of lesions due to partial displacement or rupture of the annulus fibrosus. Such occurrences, typically resulting from physical trauma, can yield disabling effects from impingement on spinal nerve structures. A greater understanding of the IVD and how it functions mechanically is crucial in prevention and repair of debilitating spinal disorders.

Automated rodent in situ muscle contraction assay and myofiber organization analysis in sarcopenia animal models

2012 ◽  
Vol 112 (12) ◽  
pp. 2087-2098 ◽  
Author(s):  
H. Weber ◽  
A. Rauch ◽  
S. Adamski ◽  
K. Chakravarthy ◽  
A. Kulkarni ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Force Measurement ◽  
Muscle Performance ◽  
Area Measurement ◽  
Micro Ct ◽  
Cross Sectional ◽  
Muscle Aging ◽  
Age Related

Age-related sarcopenia results in frailty and decreased mobility, which are associated with increased falls and long-term disability in the elderly. Given the global increase in lifespan, sarcopenia is a growing, unmet medical need. This report aims to systematically characterize muscle aging in preclinical models, which may facilitate the development of sarcopenia therapies. Naïve rats and mice were subjected to noninvasive micro X-ray computed tomography (micro-CT) imaging, terminal in situ muscle function characterizations, and ATPase-based myofiber analysis. We developed a Definiens (Parsippany, NJ)-based algorithm to automate micro-CT image analysis, which facilitates longitudinal in vivo muscle mass analysis. We report development and characterization of translational in situ skeletal muscle performance assay systems in rat and mouse. The systems incorporate a custom-designed animal assay stage, resulting in enhanced force measurement precision, and LabVIEW (National Instruments, Austin, TX)-based algorithms to support automated data acquisition and data analysis. We used ATPase-staining techniques for myofibers to characterize fiber subtypes and distribution. Major parameters contributing to muscle performance were identified using data mining and integration, enabled by Labmatrix (BioFortis, Columbia, MD). These technologies enabled the systemic and accurate monitoring of muscle aging from a large number of animals. The data indicated that longitudinal muscle cross-sectional area measurement effectively monitors change of muscle mass and function during aging. Furthermore, the data showed that muscle performance during aging is also modulated by myofiber remodeling factors, such as changes in myofiber distribution patterns and changes in fiber shape, which affect myofiber interaction. This in vivo muscle assay platform has been applied to support identification and validation of novel targets for the treatment of sarcopenia.

scholarly journals Mild Cognitive Impairment or Attention-Deficit/Hyperactivity Disorder in Older Adults? A Cross Sectional Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Felippe Mendonca ◽  
Felipe Kenji Sudo ◽  
Gustavo Santiago-Bravo ◽  
Natalia Oliveira ◽  
Naima Assuncao ◽  
...  
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Attention Deficit ◽  
Cross Sectional Study ◽  
Older Individuals ◽  
Sectional Study ◽  
Cross Sectional ◽  
Hyperactivity Disorder ◽  
Age Related

Background: Attention-Deficit/Hyperactivity Disorder (ADHD) is a highly prevalent neurodevelopmental condition, which may be associated with life-enduring cognitive dysfunction. It has been hypothesized that age-related cognitive decline may overlap with preexisting deficits in older ADHD patients, leading to increased problems to manage everyday-life activities. This phenomenon may mimic neurodegenerative disorders, in particular Mild Cognitive Impairment (MCI). This cross-sectional study aims to assess cognitive and behavioral differences between older subjects with ADHD and MCI.Methods: A total of 107 older participants (41 controls; 40 MCI and 26 ADHD; mean age = 67.60 ± 7.50 years; mean schooling = 15.14 ± 2.77 years; 65.4% females) underwent clinical, cognitive, and behavioral assessments by a multidisciplinary team at the Memory Clinic, D'Or Institute for Research and Education, Rio de Janeiro, Brazil. Mean scores in neuropsychological tasks and behavioral scales were compared across groups.Results: Participants with ADHD showed poorer performances than controls in episodic memory and executive function with large effect-sizes. Performances were comparable between MCI and ADHD for all domains.Discussion: MCI and ADHD in older individuals are dissociated clinical entities with overlapping cognitive profiles. Clinicians ought to be aware of these converging phenotypes to avoid misdiagnosis.

Muscular Strength is Independently Associated with Cystatin C: The KORA-Age Study

2018 ◽  
Vol 39 (03) ◽  
pp. 225-231 ◽  
Author(s):  
Konstantinos Volaklis ◽  
Barbara Thorand ◽  
Anette Peters ◽  
Martin Halle ◽  
Heier Margot ◽  
...  
Keyword(s):  
Older Adults ◽  
Cystatin C ◽  
Muscular Strength ◽  
Smoking Status ◽  
Fat Free Mass ◽  
Older Individuals ◽  
Cross Sectional ◽  
Age Related ◽  
Health Related ◽  
Hs Crp

AbstractThe purpose of this study was to investigate if there is a link between muscular strength (MS) and markers of chronic kidney disease (CKD) among older adults. The cross-sectional analysis based on 1041 men and women, aged 65–94 years, who participated in the KORA-Age study. Participants underwent an interview and extensive examinations including anthropometric measurements, diseases and drug intake registration, determination of health-related behaviors, collection of blood samples for measurements of cystatin C and maximal muscle strength evaluation. One-Way ANOVA revealed significant differences in both mean cystatin C (1.16±0.37 vs. 1.03±0.29 vs. 0.93±0.24 mg/L, p<0.001) and mean eGFRcysC (63.61±18.61 vs. 72.14±18.92 vs. 79.87±18.19 ml/min/1.73 m2, p<0.05) across thirds of maximal muscular strength (from lowest to highest). MS in the lowest third was significantly associated with increased odds of having elevated cystatin C (OR: 1.70, 95% CI: 1.01–2.85, p=0.043) after controlling for age, gender, fat mass, fat-free mass, alcohol intake, smoking status, number of regularly used medications, multimorbidity status, hs-CRP, telomere length and levels of physical activity. Lower levels of MS are independently associated with higher concentrations of cystatin C and lower eGFRcysC in older individuals. Increasing the levels of muscular strength may be useful to prevent the age-related CKD disease of older adults.

scholarly journals Attitudes Towards Digital Health Technology: Introducing the Digital Health Scale

2021 ◽  
Author(s):  
Ridley Cassidy
Keyword(s):  
Digital Health ◽  
Health Technology ◽  
Healthcare Services ◽  
Older Individuals ◽  
Cross Sectional ◽  
Frequent Use ◽  
Age Related ◽  
Frequency Of Use ◽  
The Uk ◽  
Digital Healthcare

Objective: The study sought to investigate the relationship between attitude towards digital health technology and age, gender and frequency of use of digital health technology and to consider whether age, gender and frequency of use present potential barriers to accessing future healthcare in the UK. Differences in technological affinity are likely to lead to differences in the adoption of digital health technology and subsequent inequalities in healthcare between older and younger people and between men and women. Design: The study represents an example of a technology adoption study employing a survey-based cross sectional correlational design. Attitude towards digital health technology was measured using the 20 item Digital Health Scale. Age, gender, frequency of use of health technology and employment status data were gathered using a demographics questionnaire. The opportunity sample (N = 247) included volunteer participants aged 16-84 years (M = 31.7, SD = 19.35, 156 females and 91 males). Results: Results indicated a significant negative correlation between age and positive attitude towards digital health technology (r = -0.24, p < .01). Gender differences in attitudes towards digital health technology were non-significant (p > .05). Significant differences in frequency of use were also found, where occasional and frequent use resulted in more positive attitudes than never having used digital health technology (p < 0.05) and participants reporting frequent use were significantly older than those reporting never or occasional use (p < .05) Conclusion: Findings identified age, but not gender, as a significant factor in attitude towards digital health technology, suggesting that continued and increased reliance on digital technology in healthcare may lead to age, but not gender, related inequalities in access to healthcare in the UK. That frequent users of digital health technology were also older, highlights the greater demand for healthcare services by older individuals and is further evidence for the potential of digital healthcare to lead to age related inequalities in access to and provision of healthcare. Recommendations for successful application of digital healthcare technology are considered in the light of these findings.

Inhibition and Switching in Healthy Aging: A Longitudinal Study

2016 ◽  
Vol 23 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Steinunn Adólfsdóttir ◽  
Daniel Wollschlaeger ◽  
Eike Wehling ◽  
Astri J. Lundervold
Keyword(s):  
Processing Speed ◽  
Predictive Value ◽  
Healthy Aging ◽  
Older Individuals ◽  
Longitudinal Models ◽  
Cross Sectional ◽  
Gender And Education ◽  
Age Related ◽  
Speed Measure ◽  
Interference Test

AbstractObjectives: Discrepant findings of age-related effects between cross-sectional and longitudinal studies on executive function (EF) have been described across different studies. The aim of the present study was to examine longitudinal age effects on inhibition and switching, two key subfunctions of EF, calculated from results on the Color Word Interference Test (CWIT). Methods: One hundred twenty-three healthy aging individuals (average age 61.4 years; 67% women) performed the CWIT up to three times, over a period of more than 6 years. Measures of inhibition, switching, and combined inhibition and switching were analyzed. A longitudinal linear mixed effects models analysis was run including basic CWIT conditions, and measures of processing speed, retest effect, gender, education, and age as predictors. Results: After taking all predictors into account, age added significantly to the predictive value of the longitudinal models of (i) inhibition, (ii) switching, and (iii) combined inhibition and switching. The basic CWIT conditions and the processing speed measure added to the predictive value of the models, while retest effect, gender, and education did not. Conclusions: The present study on middle-aged to older individuals showed age-related decline in inhibition and switching abilities. This decline was retained even when basic CWIT conditions, processing speed, attrition, gender, and education were controlled. (JINS, 2017, 23, 90–97)

scholarly journals Age Differences and Longitudinal Change in Exposure to Daily Stressors: Three Waves of Diary Data Across 20 Years

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 215-215
Author(s):  
Eric Cerino ◽  
Jonathan Rush ◽  
Robert Stawski
Keyword(s):  
Age Differences ◽  
Healthy Aging ◽  
Later Life ◽  
Longitudinal Change ◽  
National Study ◽  
Older Individuals ◽  
Daily Stress ◽  
Cross Sectional ◽  
Telephone Interviews ◽  
Age Related

Abstract Exposure to daily stress is an important risk factor for healthy aging. We examined cross-sectional age-related differences and longitudinal aging-related change in stressor exposure across three waves of the National Study of Daily Experiences (N=2,914, M=51.53 years, SD=13.55, 56.35% Female) spanning 20 years. Exposure to six types of stressors (arguments, avoided arguments, work overloads, home overloads, network stressors, other) were obtained from telephone interviews over 8 consecutive days in waves conducted in ~1996, ~2008, and ~2017. Longitudinal analyses revealed declines in stressor exposure across 20 years (p&lt;.01), driven by declines in arguments, work overloads, and network stressors specifically. Cross-sectional analyses indicated that older individuals reported stressors less frequently (p&lt;.01), driven by decreases in arguments, avoided arguments, work overloads, and home overloads specifically. Rates of longitudinal decline did not depend on age at baseline. Results suggest that aging-related changes and baseline age differences inform daily stress trajectories in mid- and later-life.

scholarly journals Az eleséstől való félelem otthon élő idősek körében

2019 ◽  
Vol 160 (5) ◽  
pp. 191-197
Author(s):  
Éva Kovács ◽  
Réka Laura Erdős ◽  
Anna Niké Petridisz ◽  
Franciska Rozs ◽  
András Simon
Keyword(s):  
Fear Of Falling ◽  
Chronic Illnesses ◽  
Functional Mobility ◽  
Older Individuals ◽  
Targeted Interventions ◽  
Age Related ◽  
Health Factors ◽  
Gender And Health ◽  
Impaired Balance ◽  
Hungarian Version

Abstract: Introduction: Due to fear of falling, older people may restrict their activities, causing muscle weakness and impaired balance and, consequently, admission to an institute. Accordingly, fear of falling is a common and serious health problem among older individuals. The prevalence of the fear of falling and its associated factors as well as possible preventive and therapeutic methods have been widely investigated in geriatrics. Aim: The aim of our study was to describe the prevalence of the fear of falling and its associations with demographic (age, gender) and health factors (age-related chronic diseases, functional mobility, falling in the previous year, medications) among community-living older adults. Method: Two-hundred individuals participated in the study. The fear of falling was diagnosed based on the cut-off value of the short Falls Efficacy Scale – International (FES-I). Logistic regression analysis was used to assess associations. In total, 61 participants were diagnosed with fear of falling. Results: In our sample, the fear of falling was associated with age, the number of diseases and functional mobility. Conclusion: The short FES-I is simple, easy to fill-out and has a validated Hungarian version as well. By its use, people of higher age affected by multiple chronic illnesses are primarily worth of screening in order to identify those who are in need for further more detailed examinations and, if needed, more targeted interventions. Orv Hetil. 2019; 160(5): 191–197.

In vivo Cross-sectional Area of Human Jaw Muscles Varies with Section Location and Jaw Position

2005 ◽  
Vol 84 (6) ◽  
pp. 570-575 ◽  
Author(s):  
T.K. Goto ◽  
M. Yahagi ◽  
Y. Nakamura ◽  
K. Tokumori ◽  
G.E.J. Langenbach ◽  
...  
Keyword(s):  
Masticatory Muscles ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Jaw Opening ◽  
Pterygoid Muscles ◽  
Jaw Position ◽  
Muscle Cross Sectional Area ◽  
Uniform Change

Muscle cross-sectional area (CSA) is used as a measure for maximum muscle force. This CSA is commonly determined at one location within the muscle and for one jaw position. The purpose of this study was to establish a method to standardize the analysis of the CSA of the masticatory muscles in vivo, and to compare the CSAs along their entire length for two different jaw positions (opened and closed). The CSAs in the planes perpendicular to the long axes of the masseter, medial, and lateral pterygoid muscles were measured in ten normal young adult subjects by magnetic resonance imaging. Our results showed large differences among the muscles and a non-uniform change in CSA after jaw-opening. The method enables the CSA measurement to be standardized in vivo, and allows for a correct comparison of CSAs in different skull morphologies.

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