GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Changes in systemic GDF15 across the adult lifespan and their impact on maximal muscle power: the Copenhagen Sarcopenia Study
    Wiley ; 2021
    In:  Journal of Cachexia, Sarcopenia and Muscle Vol. 12, No. 6 ( 2021-12), p. 1418-1427
    Details
    In: Journal of Cachexia, Sarcopenia and Muscle, Wiley, Vol. 12, No. 6 ( 2021-12), p. 1418-1427
    Abstract: Although growth differentiation factor 15 (GDF15) is known to increase with disease and is associated with low physical performance, the role of GDF15 in normal ageing is still not fully understood. Specifically, the influence of circulating GDF15 on impairments in maximal muscle power (a major contributor to functional limitations) and the underlying components has not been investigated. Methods Data from 1305 healthy women and men aged 20 to 93 years from The Copenhagen Sarcopenia Study were analysed. Circulating levels of GDF15 and markers of inflammation (tumor necrosis factor‐alpha, interleukin‐6, and high‐sensitivity C‐reactive protein) were measured by ELISA (R & D Systems) and multiplex bead‐based immunoassays (Bio‐Rad). Relative (normalized to body mass), allometric (normalized to height squared), and specific (normalized to leg muscle mass) muscle power were assessed by the Nottingham power rig [leg extension power (LEP)] and the 30 s sit‐to‐stand (STS) muscle power test. Total body fat, visceral fat, and leg lean mass were assessed by dual energy X‐ray absorptiometry. Leg skeletal muscle index was measured as leg lean mass normalized to body height squared. Results Systemic levels of GDF15 increased progressively as a function of age in women (1.1 ± 0.4 pg·mL −1 ·year −1 ) and men (3.3 ± 0.6 pg·mL −1 ·year −1 ) (both P   〈  0.05). Notably, GDF15 increased at a faster rate from the age of 65 years in women (11.5 ± 1.2 pg·mL −1 ·year −1 , P   〈  0.05) and 70 years in men (19.3 ± 2.3 pg·mL −1 ·year −1 , P   〈  0.05), resulting in higher GDF15 levels in men compared with women above the age of 65 years ( P   〈  0.05). Independently of age and circulatory markers of inflammation, GDF15 was negatively correlated to relative STS power ( P   〈  0.05) but not LEP, in both women and men. These findings were mainly explained by negative associations of GDF15 with specific STS power in women and men (both P   〈  0.05). Conclusions A J‐shaped relationship between age and systemic GDF15 was observed, with men at older age showing steeper increases and elevated GDF15 levels compared with women. Importantly, circulating GDF15 was independently and negatively associated with relative STS power, supporting the potential role of GDF15 as a sensitive biomarker of frailty in older people.
    Type of Medium: Online Resource
    ISSN: 2190-5991 , 2190-6009
    URL: Issue
    URL: Article
    DOI: 10.1002/jcsm.v12.6
    DOI: 10.1002/jcsm.12823
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2586864-0
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Exercise-induced fluid shifts are distinct to exercise mode and intensity: a comparison of blood flow-restricted and free-flow resistance exercise
    American Physiological Society ; 2021
    In:  Journal of Applied Physiology Vol. 130, No. 6 ( 2021-06-01), p. 1822-1835
    Details
    In: Journal of Applied Physiology, American Physiological Society, Vol. 130, No. 6 ( 2021-06-01), p. 1822-1835
    Abstract: MRI can provide fundamental tools in decoding physiological stressors stimulated by training paradigms. Acute physiological changes induced by three diverse exercise protocols known to elicit similar levels of muscle hypertrophy were evaluated using muscle functional magnetic resonance imaging (mfMRI). The study was a cross-over study with participants ( n = 10) performing three acute unilateral knee extensor exercise protocols to failure and a work matched control exercise protocol. Participants were scanned after each exercise protocol; 70% 1 repetition maximum (RM) (FF70); 20% 1RM (FF20); 20% 1RM with blood flow restriction (BFR20); free-flow (FF) control work matched to BFR20 (FF20 WM ). Post exercise mfMRI scans were used to obtain interleaved measures of muscle R2 (indicator of edema), R2′ (indicator of deoxyhemoglobin), muscle cross sectional area (CSA) blood flow, and diffusion. Both BFR20 and FF20 exercise resulted in a larger acute decrease in R2, decrease in R2′, and expansion of the extracellular compartment with slower rates of recovery. BFR20 caused greater acute increases in muscle CSA than FF20 WM and FF70. Only BFR20 caused acute increases in intracellular volume. Postexercise muscle blood flow was higher after FF70 and FF20 exercise than BFR20. Acute changes in mean diffusivity were similar across all exercise protocols. This study was able to differentiate the acute physiological responses between anabolic exercise protocols. Low-load exercise protocols, known to have relatively higher energy contributions from glycolysis at task failure, elicited a higher mfMRI response. Noninvasive mfMRI represents a promising tool for decoding mechanisms of anabolic adaptation in muscle. NEW & NOTEWORTHY Using muscle functional MRI (mfMRI), this study was able to differentiate the acute physiological responses following three established hypertrophic resistance exercise strategies. Low-load exercise protocols performed to failure, with or without blood flow restriction, resulted in larger changes in R 2 (i.e. greater T 2 -shifts) with a slow rate of return to baseline indicative of myocellular fluid shifts. These data were cross evaluated with interleaved measures of macrovascular blood flow, water diffusion, muscle cross sectional area (i.e. acute macroscopic muscle swelling), and intracellular water fraction measured using MRI.
    Type of Medium: Online Resource
    ISSN: 8750-7587 , 1522-1601
    URL: Article
    DOI: 10.1152/japplphysiol.01012.2020
    RVK:
    WA 15000
    RVK:
    XA 52094
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2021
    detail.hit.zdb_id: 1404365-8
    SSG: 12
    SSG: 31
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Age- and Sex-Specific Changes in Lower-Limb Muscle Power Throughout the Lifespan
    Oxford University Press (OUP) ; 2020
    In:  The Journals of Gerontology: Series A Vol. 75, No. 7 ( 2020-06-18), p. 1369-1378
    Details
    In: The Journals of Gerontology: Series A, Oxford University Press (OUP), Vol. 75, No. 7 ( 2020-06-18), p. 1369-1378
    Abstract: Our main goal was to evaluate the pattern and time course of changes in relative muscle power and its constituting components throughout the life span. Methods A total of 1,305 subjects (729 women and 576 men; aged 20–93 years) participating in the Copenhagen Sarcopenia Study took part. Body mass index (BMI), leg lean mass assessed by dual-energy X-ray absorptiometry (DXA), and leg extension muscle power (LEP) assessed by the Nottingham power rig were recorded. Relative muscle power (normalized to body mass) and specific muscle power (normalized to leg lean mass) were calculated. Segmented regression analyses were used to identify the onset and pattern of age-related changes in the recorded variables. Results Relative muscle power began to decline above the age of 40 in both women and men, with women showing an attenuation of the decline above 75 years. Relative muscle power decreased with age due to (i) the loss of absolute LEP after the fourth decade of life and (ii) the increase in BMI up to the age of 75 years in women and 65 years in men. The decline in absolute LEP was caused by a decline in specific LEP up to the age of 75 in women and 65 in men, above which the loss in relative leg lean mass also contributed. Conclusions Relative power decreased (i) above 40 years by the loss in absolute power (specific power only) and the increase in body mass, and (ii) above ~70 years by the loss in absolute power (both specific power and leg lean mass).
    Type of Medium: Online Resource
    ISSN: 1079-5006 , 1758-535X
    URL: Article
    DOI: 10.1093/gerona/glaa013
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2020
    detail.hit.zdb_id: 2043927-1
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Physiological responses of human skeletal muscle to acute blood flow restricted exercise assessed by multimodal MRI
    American Physiological Society ; 2020
    In:  Journal of Applied Physiology Vol. 129, No. 4 ( 2020-10-01), p. 748-759
    Details
    In: Journal of Applied Physiology, American Physiological Society, Vol. 129, No. 4 ( 2020-10-01), p. 748-759
    Abstract: Important physiological quantities for investigating muscle hypertrophy include blood oxygenation, cell swelling, and changes in blood flow. The purpose of this study was to compare the acute changes of these parameters in human skeletal muscle induced by low-load (20% 1-RM) blood flow-restricted (BFR-20) knee extensor exercise compared with free-flow work-matched (FF-20 WM ) and free-flow 50% 1-RM (FF-50) knee extensor exercise using multimodal magnetic resonance imaging (MRI). Subjects ( n = 11) completed acute exercise sessions for each exercise mode in an MRI scanner, where interleaved measures of muscle R 2 (indicator of edema), [Formula: see text] (indicator of deoxyhemoglobin), macrovascular blood flow, and diffusion were performed before, between sets, and after the final set for each exercise protocol. BFR-20 exercise resulted in larger acute decreases in R 2 and greater increases in cross-sectional area than FF-20 WM and FF-50 ( P 〈 0.01). Blood oxygenation decreased between sets during BFR-20, as indicated by a 13.6% increase in [Formula: see text] values ( P 〈 0.01)), whereas they remained unchanged for FF-20 WM and decreased during FF-50 exercise. Quadriceps blood flow between sets was highest for the heavier load (FF-50), averaging 305 mL/min, and lowest for BFR-20 at 123 ± 73 mL/min until post-exercise cuff release, where blood flow rates in BFR-20 exceeded both FF protocols ( P 〈 0.01). Acute changes in diffusion rates were similar for all exercise protocols. This study was able to differentiate the acute exercise response of selected physiological factors associated with skeletal muscle hypertrophy. Marked differences in these parameters were found to exist between BFR and FF exercise conditions, which contribute to explain the anabolic potential of low-load blood flow restricted muscle exercise. NEW & NOTEWORTHY Acute changes in blood flow, diffusion, blood oxygenation, cross-sectional area, and the “T 2 shift” are evaluated in human skeletal muscle in response to blood flow-restricted (BFR) and conventional free-flow knee extensor exercise performed in an MRI scanner. The acute physiological response to exercise was dependent on the magnitude of load and the application of BFR. Physiological variables changed markedly and established a steady state rapidly after the first of four exercise sets.
    Type of Medium: Online Resource
    ISSN: 8750-7587 , 1522-1601
    URL: Article
    DOI: 10.1152/japplphysiol.00171.2020
    RVK:
    WA 15000
    RVK:
    XA 52094
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2020
    detail.hit.zdb_id: 1404365-8
    SSG: 12
    SSG: 31
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Assessment of functional sit-to-stand muscle power: Cross-sectional trajectories across the lifespan
    Elsevier BV ; 2021
    In:  Experimental Gerontology Vol. 152 ( 2021-09), p. 111448-
    Details
    In: Experimental Gerontology, Elsevier BV, Vol. 152 ( 2021-09), p. 111448-
    Type of Medium: Online Resource
    ISSN: 0531-5565
    URL: Article
    DOI: 10.1016/j.exger.2021.111448
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
    detail.hit.zdb_id: 2005397-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    The Copenhagen Sarcopenia Study: lean mass, strength, power, and physical function in a Danish cohort aged 20–93 years
    Wiley ; 2019
    In:  Journal of Cachexia, Sarcopenia and Muscle Vol. 10, No. 6 ( 2019-12), p. 1316-1329
    Details
    In: Journal of Cachexia, Sarcopenia and Muscle, Wiley, Vol. 10, No. 6 ( 2019-12), p. 1316-1329
    Abstract: Despite no international consensus on the diagnostic criteria for sarcopenia, low lean mass, muscle strength, and physical function are important risk factors for disability, frailty, and mortality in older individuals, as well as in a wide range of patients with muscle loss. Here, we provide a population‐based reference material of total and regional lean body mass, muscle strength/power parameters, and physical function in a healthy cohort of Danish men and women across the lifespan. Methods Volunteers aged 20–93 years from the Copenhagen City Heart Study were invited to establish a Danish reference material (Copenhagen Sarcopenia Study) on lean mass characteristics [appendicular lean mass (ALM), iDXA, GE Lunar], muscle function [handgrip strength (HGS), Jamar dynamometer and leg extension power (LEP), Nottingham Power Rig] , and physical function [30 s sit‐to‐stand test (STS), 10‐m maximal and habitual gait speed (GS)]. Results A total of 1305 participants [729 women (age: 56.4 ± 18.9 years, height: 1.66 ± 0.01 m, body mass index: 24.6 ± 4.3 kg/m 2 and 576 men, age: 57.0 ± 17.5 years, height: 1.80 ± 0.07 m, body mass index: 26.0 ± 3.9 kg/m 2 ] completed all measurements and were included in the present analysis. Lean mass characteristics (TLM, ALM, and ALM/h 2 ) decreased with increasing age in both men and women ( P 〈 0.001). Men demonstrated larger absolute and relative total ALM and higher HGS and LEP compared with women at all age intervals ( P 〈 0.001). HGS and LEP decreased progressively with age in both men and women ( P 〈 0.01); 30 s STS performance, habitual GS, and maximal GS decreased at an accellerated rate of decline with increasing age in both men and women ( P 〈 0.001). Habitual GS was reduced in men and women aged ≥70 years, while maximal GS was reduced from the age of ≥60 years compared with young adults ( P 〈 0.001). Regardless of sex, 30 s STS was reduced from the age of ≥50 years compared with the young reference group ( P 〈 0.001) Conclusions While the power‐based measurements (LEP and 30 s STS) started to decline already at age +50 years, less power‐based parameters (GS and HGS) and lean mass characteristics (TLM, ALM, and ALM/h 2 ) remained unaltered until after the age of +70 years. Notably, the cut‐off thresholds derived in the present study differed from earlier reference data, which underlines the importance of obtaining updated and local reference materials.
    Type of Medium: Online Resource
    ISSN: 2190-5991 , 2190-6009
    URL: Issue
    URL: Article
    DOI: 10.1002/jcsm.v10.6
    DOI: 10.1002/jcsm.12477
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 2586864-0
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...