scholarly journals Body-building without power training: endogenously regulated pectoral muscle hypertrophy in confined shorebirds

1999 ◽  
Vol 202 (20) ◽  
pp. 2831-2837 ◽  
Author(s):  
M.W. Dietz ◽  
T. Piersma ◽  
A. Dekinga
Keyword(s):  
Muscle Mass ◽  
Body Mass ◽  
Muscle Hypertrophy ◽  
Pectoral Muscle ◽  
Muscle Size ◽  
Power Training ◽  
Diet Change ◽  
Circannual Rhythm ◽  
Migration Patterns ◽  
Calidris Canutus

Shorebirds such as red knots Calidris canutus routinely make migratory flights of 3000 km or more. Previous studies on this species, based on compositional analyses, suggest extensive pectoral muscle hypertrophy in addition to fat storage before take-off. Such hypertrophy could be due to power training and/or be effected by an endogenous circannual rhythm. Red knots of two subspecies with contrasting migration patterns were placed in a climate-controlled aviary (12 h:12 h L:D photoperiod) where exercise was limited. Using ultrasonography, we measured pectoral muscle size as the birds stored fat in preparation for migration. At capture, there were no differences in body mass and pectoral muscle mass between the two subspecies. As they prepared for southward and northward migration, respectively, the tropically wintering subspecies (C. c. canutus) gained 31 g and the temperate wintering subspecies (C. c. islandica) gained 41 g. During this time, pectoral mass increased by 43–44 % of initial mass, representing 39 % (C. c. canutus) and 29 % (C. c. islandica) of the increase in body mass. The gizzard showed atrophy in conjunction with a diet change from molluscs to food pellets. Although we cannot exclude the possibility that the birds' limited movement may still be a prerequisite for pectoral muscle hypertrophy, extensive power training is certainly not a requirement. Muscle hypertrophy in the absence of photoperiod cues suggests the involvement of an endogenous circannual process.

scholarly journals Thermogenic side effects to migratory predisposition in shorebirds

2007 ◽  
Vol 292 (3) ◽  
pp. R1287-R1297 ◽  
Author(s):  
François Vézina ◽  
Kirsten M. Jalvingh ◽  
Anne Dekinga ◽  
Theunis Piersma
Keyword(s):  
Side Effects ◽  
Metabolic Rate ◽  
Body Mass ◽  
Muscle Hypertrophy ◽  
Significant Proportion ◽  
Pectoral Muscle ◽  
Thermal Acclimation ◽  
Muscle Size ◽  
Long Distance ◽  
Thermogenic Capacity

In the calidrine sandpiper red knot ( Calidris canutus), the weeks preceding takeoff for long-distance migration are characterized by a rapid increase in body mass, largely made up of fat but also including a significant proportion of lean tissue. Before takeoff, the pectoral muscles are known to hypertrophy in preparation for endurance flight without any specific training. Because birds facing cold environments counterbalance heat loss through shivering thermogenesis, and since pectoral muscles represent a large proportion of avian body mass, we asked the question whether muscle hypertrophy in preparation for long-distance endurance flight would induce improvements in thermogenic capacity. We acclimated red knots to different controlled thermal environments: 26°C, 5°C, and variable conditions tracking outdoor temperatures. We then studied within-individual variations in body mass, pectoral muscle size (measured by ultrasound), and metabolic parameters [basal metabolic rate (BMR) and summit metabolic rate (Msum)] throughout a 3-mo period enclosing the migratory gain and loss of mass. The gain in body mass during the fattening period was associated with increases in pectoral muscle thickness and thermogenic capacity independent of thermal acclimation. Regardless of their thermal treatment, birds showing the largest increases in body mass also exhibited the largest increases in Msum. We conclude that migratory fattening is accompanied by thermoregulatory side effects. The gain of body mass and muscle hypertrophy improve thermogenic capacity independent of thermal acclimation in this species. Whether this represents an ecological advantage depends on the ambient temperature at the time of fattening.

scholarly journals Avian pectoral muscle size rapidly tracks body mass changes during flight, fasting and fuelling

2000 ◽  
Vol 203 (5) ◽  
pp. 913-919 ◽  
Author(s):  
A. Lindstrom ◽  
A. Kvist ◽  
T. Piersma ◽  
A. Dekinga ◽  
M.W. Dietz
Keyword(s):  
Muscle Mass ◽  
Body Mass ◽  
Muscle Thickness ◽  
Pectoral Muscle ◽  
The Body ◽  
Muscle Size ◽  
Migratory Flight ◽  
Avian Muscle ◽  
Require Power ◽  
Body Mass Changes

We used ultrasonic imaging to monitor short-term changes in the pectoral muscle size of captive red knots Calidris canutus. Pectoral muscle thickness changed rapidly and consistently in parallel with body mass changes caused by flight, fasting and fuelling. Four knots flew repeatedly for 10 h periods in a wind tunnel. Over this period, pectoral muscle thickness decreased in parallel with the decrease in body mass. The change in pectoral muscle thickness during flight was indistinguishable from that during periods of natural and experimental fasting and fuelling. The body-mass-related variation in pectoral muscle thickness between and within individuals was not related to the amount of flight, indicating that changes in avian muscle do not require power-training as in mammals. Our study suggests that it is possible for birds to consume and replace their flight muscles on a time scale short enough to allow these muscles to be used as part of the energy supply for migratory flight. The adaptive significance of the changes in pectoral muscle mass cannot be explained by reproductive needs since our knots were in the early winter phase of their annual cycle. Instead, pectoral muscle mass changes may reflect (i) the breakdown of protein during heavy exercise and its subsequent restoration, (ii) the regulation of flight capacity to maintain optimal flight performance when body mass varies, or (iii) the need for a particular protein:fat ratio in winter survival stores.

Viral expression of insulin-like growth factor-I isoforms promotes different responses in skeletal muscle

2006 ◽  
Vol 100 (6) ◽  
pp. 1778-1784 ◽  
Author(s):  
Elisabeth R. Barton
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Muscle Mass ◽  
Muscle Hypertrophy ◽  
Muscle Development ◽  
Muscle Size ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Insulin-like growth factor I (IGF-I) is a critical protein for skeletal muscle development and regeneration. Its ability to promote skeletal muscle hypertrophy has been demonstrated by several methods. Alternative splicing of the Igf-1 gene does not affect the mature IGF-I protein but does produce different E peptide extensions, which have been reported to modify the potency of IGF-I. Viral-mediated delivery of murine IGF-IA and IGF-IB into skeletal muscle of 2-wk-old and 6-mo-old mice was utilized to compare the effects of the isoforms on muscle mass. In young mice, tissue content of IGF-I protein was significantly higher in rAAV-treated muscles than control muscles at 1, 2, and 4 mo postinjection. Viral injection of IGF-IB produced two- to sevenfold more IGF-I than rAAVIGF-IA. Hypertrophy was observed 2 and 4 mo postinjection, where both rAAVIGF-IA and rAAVIGF-IB were equally effective in increasing muscle mass. These results suggest that there is a threshold of IGF-I production necessary to promote muscle hypertrophy in young growing animals regardless of isoform. In 6-mo-old animals, only rAAVIGF-IA produced significant increases in muscle size, even though increased IGF-I content was observed after injection of both isoforms. Therefore, the ability for IGF-IB to promote muscle hypertrophy is only effective in growing animals, suggesting that the bioavailability of this isoform or its receptor affinity diminishes with age.

scholarly journals Acute daily psychological stress causes increased atrophic gene expression and myostatin-dependent muscle atrophy

2010 ◽  
Vol 299 (3) ◽  
pp. R889-R898 ◽  
Author(s):  
David L. Allen ◽  
Gary E. McCall ◽  
Amanda S. Loh ◽  
Molly C. Madden ◽  
Ryan S. Mehan
Keyword(s):  
Gene Expression ◽  
Muscle Mass ◽  
Psychological Stress ◽  
Body Mass ◽  
Ring Finger ◽  
Muscle Size ◽  
Mrna Levels ◽  
Phosphatidylinositol 3 Kinase ◽  
Axis Body ◽  
Pituitary Adrenal Axis

Psychological stress is known to attenuate body size and lean body mass. We tested the effects of 1, 3, or 7 days of two different models of psychological stress, 1 h of daily restraint stress (RS) or daily cage-switching stress (CS), on skeletal muscle size and atrophy-associated gene expression in mice. Thymus weights decreased in both RS and CS mice compared with unstressed controls, suggesting that both models activated the hypothalamic-pituitary-adrenal axis. Body mass was significantly decreased at all time points for both models of stress but was greater for RS than CS. Mass of the tibialis anterior (TA) and soleus (SOL) muscles was significantly decreased after 3 and 7 days of RS, but CS only significantly decreased SOL mass after 7 days. TA mRNA levels of the atrophy-associated genes myostatin (MSTN), atrogin-1, and the phosphatidylinositol 3-kinase inhibitory subunit p85α were all significantly increased relative to unstressed mice after 1 and 3 days of RS, and expression of MSTN and p85α mRNA remained elevated after 7 days of RS. Expression of muscle ring finger 1 was increased after 1 day of RS but returned to baseline at 3 and 7 days of RS. MSTN, atrogin-1, and p85α mRNA levels also significantly increased after 1 and 3 days of CS but atrogen-1 mRNA levels had resolved back to normal levels by 3 days and p85α with 7 days of CS. p21CIP mRNA levels were significantly decreased by 3 days of CS or RS. Finally, body mass was minimally affected, and muscle mass was completely unaffected by 3 days of RS in mice null for the MSTN gene, and MSTN inactivation attenuated the increase in atrogin-1 mRNA levels with 4 days of RS compared with wild-type mice. Together these data suggest that acute daily psychological stress induces atrophic gene expression and loss of muscle mass that appears to be MSTN dependent.

scholarly journals Intraspecific variation in avian pectoral muscle mass: constraints on maintaining manoeuvrability with increasing body mass

2007 ◽  
Vol 21 (2) ◽  
pp. 317-326 ◽  
Author(s):  
MAURINE W. DIETZ ◽  
THEUNIS PIERSMA ◽  
ANDERS HEDENSTRÖM ◽  
MAARTEN BRUGGE
Keyword(s):  
Muscle Mass ◽  
Body Mass ◽  
Intraspecific Variation ◽  
Pectoral Muscle

Age-Related Loss of Muscle Mass, Strength, and Power and Their Association With Mobility in Recreationally-Active Older Adults in the United Kingdom

2015 ◽  
Vol 23 (3) ◽  
pp. 352-360 ◽  
Author(s):  
Thomas M. Maden-Wilkinson ◽  
Jamie S. McPhee ◽  
David A. Jones ◽  
Hans Degens
Keyword(s):  
Older Adults ◽  
Muscle Mass ◽  
Body Mass ◽  
Functional Performance ◽  
Muscle Size ◽  
Timed Up And Go ◽  
Lower Velocity ◽  
The United Kingdom ◽  
Age Related ◽  
Force Ratio

To investigate reasons for the age-related reduction in physical function, we determined the relationships between muscle size, strength, and power with 6-min walk distance (6MWD) and timed up-and-go performance in 49 young (23 ± 3.1 years) and 66 healthy, mobile older adults (72 ± 5 years). While muscle mass, determined by DXA and MRI, did not correlate with performance in the older adults, power per body mass, determined from a countermovement jump, did correlate. The 40% lower jumping power observed in older adults (p < .05) was due to a lower take-off velocity, which explained 34% and 42% of the variance in 6MWD in older women and men, respectively (p < .01). The lower velocity was partly attributable to the higher body mass to maximal force ratio, but most was due to a lower intrinsic muscle speed. While changes in muscle function explain part of the age-related reduction in functional performance, ~60% of the deficit remains to be explained.

scholarly journals The effect of resistance training programs on lean body mass in postmenopausal and elderly women: a meta-analysis of observational studies

2021 ◽  
Author(s):  
Ewan Thomas ◽  
Ambra Gentile ◽  
Nemanja Lakicevic ◽  
Tatiana Moro ◽  
Marianna Bellafiore ◽  
...  
Keyword(s):  
Resistance Training ◽  
Lean Body Mass ◽  
Muscle Mass ◽  
Body Mass ◽  
Fat Mass ◽  
Muscle Hypertrophy ◽  
Elderly Women ◽  
Functional Changes ◽  
Training Frequency

AbstractAging and menopause are associated with morphological and functional changes which may lead to loss of muscle mass and therefore quality of life. Resistance training (RT) is an effective training mode to increase muscle mass. We reviewed the existing literature to identify studies implementing RT protocols and evaluating muscle hypertrophy exclusively in healthy, postmenopausal and elderly women. Participants’ age range was comprised between 50 and 80 years. The primary outcome observed was muscle hypertrophy. Fat mass was also evaluated, if available. PubMed and Web of Science were the screened database, and original articles written in English and published from 2000 up to 2020 were included. 26 articles were considered eligible and included. Quality assessment revealed a “moderate quality” of the included studies, however the majority of studies was able to reach level 4 of evidence and on overall grade of recommendation C. In total, data from 745 female participants subjected to different forms of resistance training were considered. Heterogeneity across studies was present regarding study design, intervention length (mean 16 weeks), training frequency (3 d/w), no. of exercises (n = 7.4) and participants’ age (65.8 ± 4.9 years). Small-to-moderate significant increases (k = 43; SMD = 0.44; 95% CI 0.28; 0.60; p < 0.0001) of lean body mass were observed in post-menopausal and elderly women, regardless of age, intervention period, weekly training frequency and no. of exercises. No effects were noted for fat mass (k = 17; SMD = 0.27; 95% CI − 0.02; 0.55; p = 0.07). Studies need to concentrate on providing information regarding training parameters to more effectively counteract the effects of aging and menopause on skeletal muscle mass.

scholarly journals MUSCLE WASTING AFTER 48 HOURS OF FOOD DEPRIVATION DIFFERS BETWEEN MOUSE STRAINS AND IS PROMOTED BY MYOSTATIN DYSFUNCTION

2016 ◽  
Vol 2 (101) ◽  
pp. 53-60
Author(s):  
Petras Minderis ◽  
Indrė Libnickienė ◽  
Aivaras Ratkevičius
Keyword(s):  
Muscle Mass ◽  
Body Mass ◽  
Food Deprivation ◽  
Muscle Hypertrophy ◽  
Muscle Wasting ◽  
Mouse Strains ◽  
Muscle Loss ◽  
Control Groups ◽  
Level Of Significance ◽  
And Control

Background. Genetic factors play an important role in determining muscle mass. Indeed, myostatin dysfunction is associated with a pronounced muscle hypertrophy. The aim of our study was to test the hypothesis that starvation induced muscle wasting differs between BEH+/+ and C57BL/6J strains of mice and myostatin dysfunction prevents muscle wasting in BEH strain. Methods. 18-week-old males of C57BL/6J, BEH+/+ and BEH were subjected to 48 h food deprivation (FD). C57BL/6J mice were representatives of classic mouse strain. BEH mice which differ from BEH+/+ mice by Compact mutation in the Mstn gene represented a model for myostatin dysfunction. All mice were divided into experimental and control groups. The control groups consisted of mice fed ad libitum. Seven mice were studied in each group. Mice were weighed before as well as 24 h and 48 h after FD which was followed by dissection and weighing of the hindlimb skeletal muscle. Results. BEH and BEH+/+ mice showed a similar (16.9 ± 1.4% vs. 19.3 ± 2.4%, p > .05) loss of body mass while loss of body mass in C57BL/6J mice was the greatest (24.8 ± 1.9%, p < .001) after FD. The loss of muscle mass was significant in both BEH (p < .001) and C57BL/6J (p < .01) mice, but it was below the level of significance (p > .05) in BEH+/+ mice. Conclusions. Myostatin dysfunction promotes muscle atrophy after FD. During short periods of FD, BEH+/+ mice are more resistant to body and muscle loss compared to C57BL/6J mice.

scholarly journals Evolutionary design of a flexible, seasonally migratory, avian phenotype: why trade gizzard mass against pectoral muscle mass?

2019 ◽  
Vol 286 (1903) ◽  
pp. 20190518 ◽  
Author(s):  
Kimberley J. Mathot ◽  
Eva M. A. Kok ◽  
Joseph B. Burant ◽  
Anne Dekinga ◽  
Petra Manche ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Body Mass ◽  
Migratory Birds ◽  
Common Factor ◽  
Pectoral Muscle ◽  
Flight Performance ◽  
Long Distance ◽  
Free Living ◽  
Explicit Consideration ◽  
Allocation Decisions

Migratory birds undergo impressive body remodelling over the course of an annual cycle. Prior to long-distance flights, red knots (Calidris canutus islandica) reduce gizzard mass while increasing body mass and pectoral muscle mass. Although body mass and pectoral muscle mass are functionally linked via their joint effects on flight performance, gizzard and pectoral muscle mass are thought to be independently regulated. Current hypotheses for observed negative within-individual covariation between gizzard and pectoral muscle mass in free-living knots are based on a common factor (e.g. migration) simultaneously affecting both traits, and/or protein limitation forcing allocation decisions. We used diet manipulations to generate within-individual variation in gizzard mass and test for independence between gizzard and pectoral muscle mass within individuals outside the period of migration and under conditions of high protein availability. Contrary to our prediction, we observed a negative within-individual covariation between gizzard and pectoral muscle mass. We discuss this result as a potential outcome of an evolved mechanism underlying body remodelling associated with migration. Although our proposed mechanism requires empirical testing, this study echoes earlier calls for greater integration of studies of function and mechanism, and in particular, the need for more explicit consideration of the evolution of mechanisms underlying phenotypic design.

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