319:
590:
balance at time of dormancy is also maintained by lower levels of protein breakdown during the winter. At times of immobility, muscle wasting in bears is also suppressed by a proteolytic inhibitor that is released in circulation. Another factor that contributes to the sustaining of muscle strength in hibernating bears is the occurrence of periodic voluntary contractions and involuntary contractions from shivering during
311:
162:
287:. The rate of muscle loss is dependent on exercise level, co-morbidities, nutrition and other factors. There are many proposed mechanisms of sarcopenia, such as a decreased capacity for oxidative phosphorylation, cellular senescence or an altered signaling of pathways regulating protein synthesis, and is considered to be the result of changes in muscle synthesis signalling pathways and gradual failure in the
2247:
43:
230:
vulnerable to dramatic muscle loss with immobility. Much of the established research has investigated prolonged disuse (>10 days), in which the muscle is compromised primarily by declines in muscle protein synthesis rates rather than changes in muscle protein breakdown. There is evidence to suggest that there may be more active protein breakdown during short term immobility (<10 days).
566:." Loss of lean body mass is also associated with increased risk of infection, decreased immunity, and poor wound healing. The weakness that accompanies muscle atrophy leads to higher risk of falls, fractures, physical disability, need for institutional care, reduced quality of life, increased mortality, and increased healthcare costs.
185:, which can be used for energy production when demands are high or supplies are low. If metabolic demands remain greater than protein synthesis, muscle mass is lost. Many diseases and conditions can lead to this imbalance, either through the disease itself or disease associated appetite-changes, such as loss of taste due to
603:
nutritional intervention. Immobilization of one of the hindlegs of mice leads to muscle-atrophy as well, and is hallmarked by loss of both muscle mass and strength. Food restriction and immobilization may be used in mouse models and have been shown to overlap with mechanisms associated to sarcopenia in humans.
589:
During hibernation, bears spend 4–7 months of inactivity and anorexia without undergoing muscle atrophy and protein loss. A few known factors contribute to the sustaining of muscle tissue. During the summer, bears take advantage of the nutrition availability and accumulate muscle protein. The protein
139:
may have some efficacy but are not often used due to side effects. There are multiple treatments and supplements under investigation but there are currently limited treatment options in clinical practice. Given the implications of muscle atrophy and limited treatment options, minimizing immobility is
134:
Muscle atrophy results from an imbalance between protein synthesis and protein degradation, although the mechanisms are incompletely understood and are variable depending on the cause. Muscle loss can be quantified with advanced imaging studies but this is not frequently pursued. Treatment depends on
492:
Physical activity provides a significant anabolic muscle stimulus and is a crucial component to slowing or reversing muscle atrophy. It is still unknown regarding the ideal exercise "dosing." Resistance exercise has been shown to be beneficial in reducing muscle atrophy in older adults. In patients
229:
Disuse is a common cause of muscle atrophy and can be local (due to injury or casting) or general (bed-rest). The rate of muscle atrophy from disuse (10–42 days) is approximately 0.5–0.6% of total muscle mass per day although there is considerable variation between people. The elderly are the most
152:
The predominant symptom is increased weakness which may result in difficulty or inability in performing physical tasks depending on what muscles are affected. Atrophy of the core or leg muscles may cause difficulty standing from a seated position, walking or climbing stairs and can cause increased
574:
Inactivity and starvation in mammals lead to atrophy of skeletal muscle, accompanied by a smaller number and size of the muscle cells as well as lower protein content. In humans, prolonged periods of immobilization, as in the cases of bed rest or astronauts flying in space, are known to result in
90:
Disuse causes rapid muscle atrophy and often occurs during injury or illness that requires immobilization of a limb or bed rest. Depending on the duration of disuse and the health of the individual, this may be fully reversed with activity. Malnutrition first causes fat loss but may progress to
602:
Muscle-atrophy can be induced in pre-clinical models (e.g. mice) to study the effects of therapeutic interventions against muscle-atrophy. Restriction of the diet, i.e. caloric restriction, leads to a significant loss of muscle mass within two weeks, and loss of muscle-mass can be rescued by a
418:
Muscle atrophy occurs due to an imbalance between the normal balance between protein synthesis and protein degradation. This involves complex cell signalling that is incompletely understood and muscle atrophy is likely the result of multiple contributing mechanisms.
258:
although it is associated with many disease processes, usually with a significant inflammatory component. Cachexia causes ongoing muscle loss that is not entirely reversed with nutritional therapy. The pathophysiology is incompletely understood but inflammatory
422:
Mitochondrial function is crucial to skeletal muscle health and detrimental changes at the level of the mitochondria may contribute to muscle atrophy. A decline in mitochondrial density as well as quality is consistently seen in muscle atrophy due to disuse.
148:
The hallmark sign of muscle atrophy is loss of lean muscle mass. This change may be difficult to detect due to obesity, changes in fat mass or edema. Changes in weight, limb or waist circumference are not reliable indicators of muscle mass changes.
529:
that was published in 2015, HMB supplementation has efficacy as a treatment for preserving lean muscle mass in older adults. More research is needed to determine the precise effects of HMB on muscle strength and function in various populations.
1746:. Proceedings of the 1st international convention on Rehabilitation engineering & assistive technology: in conjunction with 1st Tan Tock Seng Hospital Neurorehabilitation Meeting. Association for Computing Machinery. pp. 221–226.
500:
Adequate calories and protein is crucial to prevent muscle atrophy. Protein needs may vary dramatically depending on metabolic factors and disease state, so high-protein supplementation may be beneficial. Supplementation of protein or
557:
Outcomes of muscle atrophy depend on the underlying cause and the health of the patient. Immobility or bed rest in populations predisposed to muscle atrophy, such as the elderly or those with disease states that commonly cause
153:
falls. Atrophy of the throat muscles may cause difficulty swallowing and diaphragm atrophy can cause difficulty breathing. Muscle atrophy can be asymptomatic and may go undetected until a significant amount of muscle is lost.
267:
causes predominantly muscle loss instead of fat loss and it is not as responsive to nutritional intervention. Cachexia can significantly compromise quality of life and functional status and is associated with poor outcomes.
581:
are an exception to this rule; species in the family
Ursidae are famous for their ability to survive unfavorable environmental conditions of low temperatures and limited nutrition availability during winter by means of
377:
Injuries or diseases of peripheral nerves supplying specific muscles can also cause muscle atrophy. This is seen in nerve injury due to trauma or surgical complication, nerve entrapment, or inherited diseases such as
2300:
2285:
299:
586:. During that time, bears go through a series of physiological, morphological, and behavioral changes. Their ability to maintain skeletal muscle number and size during disuse is of significant importance.
279:
is the degenerative loss of skeletal muscle mass, quality, and strength associated with aging. This involves muscle atrophy, reduction in number of muscle fibers and a shift towards "slow twitch" or
1929:
Wu H, Xia Y, Jiang J, Du H, Guo X, Liu X, et al. (2015). "Effect of beta-hydroxy-beta-methylbutyrate supplementation on muscle loss in older adults: a systematic review and meta-analysis".
390:
Some medications are known to cause muscle atrophy, usually due to direct effect on muscles. This includes glucocorticoids causing glucocorticoid myopathy or medications toxic to muscle such as
562:, can cause dramatic muscle atrophy and impact on functional outcomes. In the elderly, this often leads to decreased biological reserve and increased vulnerability to stressors known as the "
2002:
Fuster G, Busquets S, Almendro V, López-Soriano FJ, Argilés JM (October 2007). "Antiproteolytic effects of plasma from hibernating bears: a new approach for muscle wasting therapy?".
477:
can be used to roughly estimate muscle loss during circumstances of rapid muscle loss. Other biomarkers are currently under investigation but are not used in clinical practice.
454:
Screening for muscle atrophy is limited by a lack of established diagnostic criteria, although many have been proposed. Diagnostic criteria for other conditions such as
2698:
505:, especially leucine, can provide a stimulus for muscle synthesis and inhibit protein breakdown and has been studied for muscle atrophy for sarcopenia and cachexia.
95:
is a wasting syndrome caused by an underlying disease such as cancer that causes dramatic muscle atrophy and cannot be completely reversed with nutritional therapy.
2527:
594:. The three to four daily episodes of muscle activity are responsible for the maintenance of muscle strength and responsiveness in bears during hibernation.
2115:
Harlow HJ, Lohuis T, Anderson-Sprecher RC, Beck TD (2004). "Body
Surface Temperature Of Hibernating Black Bears May Be Related To Periodic Muscle Activity".
353:
Damage to neurons in the brain or spinal cord can cause prominent muscle atrophy. This can be localized muscle atrophy and weakness or paralysis such as in
2042:
Lohuis TD, Harlow HJ, Beck TD (May 2007). "Hibernating black bears (Ursus americanus) experience skeletal muscle protein balance during winter anorexia".
485:
Muscle atrophy can be delayed, prevented and sometimes reversed with treatment. Treatment approaches include impacting the signaling pathways that induce
438:
pathway is one mechanism by which proteins are degraded in muscle. This involves specific proteins being tagged for destruction by a small peptide called
2077:
Carey HV, Andrews MT, Martin SL (October 2003). "Mammalian hibernation: cellular and molecular responses to depressed metabolism and low temperature".
575:
muscle weakening and atrophy. Such consequences are also noted in small hibernating mammals like the golden-mantled ground squirrels and brown bats.
2745:
860:
Wall BT, Dirks ML, van Loon LJ (September 2013). "Skeletal muscle atrophy during short-term disuse: implications for age-related sarcopenia".
549:, while still promoting muscle and bone tissue growth and regeneration. These effects have yet to be confirmed in larger clinical trials.
127:
of muscular atrophy are classified as disease spectrums or disease entities rather than as clinical syndromes alone, such as the various
649:
1549:
Abrigo J, Simon F, Cabrera D, Vilos C, Cabello-Verrugio C (2019-05-20). "Mitochondrial
Dysfunction in Skeletal Muscle Pathologies".
2193:"Caloric Restriction Combined with Immobilization as Translational Model for Sarcopenia Expressing Key-Pathways of Human Pathology"
1315:"Determinants of muscle preservation in individuals with cerebral palsy across the lifespan: a narrative review of the literature"
623:
541:
may be administered to patients as a potential treatment although use is limited by side effects. A novel class of drugs, called
517:, has demonstrated efficacy in preventing the loss of muscle mass in several muscle wasting conditions in humans, particularly
2733:
1759:
1636:
1362:
Wong A, Pomerantz JH (March 2019). "The Role of Muscle Stem Cells in
Regeneration and Recovery after Denervation: A Review".
542:
247:
206:
2543:
Exaggerated cardiorespiratory response to exercise (tachycardia with tachypnea and/or hyperpnea (exercise hyperventilation))
1085:
903:
Evans WJ, Morley JE, Argilés J, Bales C, Baracos V, Guttridge D, et al. (December 2008). "Cachexia: a new definition".
60:
379:
294:
Sarcopenia can lead to reduction in functional status and cause significant disability but is a distinct condition from
2808:
2389:
2833:
2152:"A novel nutritional supplement prevents muscle loss and accelerates muscle mass recovery in caloric-restricted mice"
1473:
729:
494:
2818:
318:
17:
2251:
506:
2128:
1879:"Beta-hydroxy-beta-methylbutyrate supplementation and skeletal muscle in healthy and muscle-wasting conditions"
2434:
334:
1828:
990:
Peterson SJ, Mozer M (February 2017). "Differentiating
Sarcopenia and Cachexia Among Patients With Cancer".
712:
Cretoiu SM, Zugravu CA (2018). "Nutritional
Considerations in Preventing Muscle Atrophy". In Xiao J (ed.).
2828:
526:
2537:
1460:. Advances in Experimental Medicine and Biology. Vol. 1088. Springer Singapore. pp. 207–233.
716:. Advances in Experimental Medicine and Biology. Vol. 1088. Springer Singapore. pp. 497–528.
470:
2764:
2598:
502:
466:
128:
1964:
Srinath R, Dobs A (February 2014). "Enobosarm (GTx-024, S-22): a potential treatment for cachexia".
814:
Seene T (July 1994). "Turnover of skeletal muscle contractile proteins in glucocorticoid myopathy".
2813:
2315:
2261:
1035:"Sex differences in skeletal muscle-aging trajectory: same processes, but with a different ranking"
243:
202:
1405:
Hiensch AE, Bolam KA, Mijwel S, Jeneson JA, Huitema AD, Kranenburg O, et al. (October 2019).
263:
are considered to play a central role. In contrast to weight loss from inadequate caloric intake,
91:
muscle atrophy in prolonged starvation and can be reversed with nutritional therapy. In contrast,
1086:"Satellite cell content is specifically reduced in type II skeletal muscle fibers in the elderly"
342:
1654:"Sarcopenia the new geriatric giant: time to translate research findings into clinical practice"
2803:
2542:
2382:
427:
362:
251:
182:
2355:
1456:
MartĂn AI, Priego T, LĂłpez-CalderĂłn A (2018). "Hormones and Muscle
Atrophy". In Xiao J (ed.).
2752:
2429:
2367:
1780:"Nutritional supplements in support of resistance exercise to counter age-related sarcopenia"
50:
The size of the muscle is reduced, as a consequence there is a loss of strength and mobility.
2257:
1407:"Doxorubicin-induced skeletal muscle atrophy: elucidating the underlying molecular pathways"
772:"Skeletal Muscle Regulates Metabolism via Interorgan Crosstalk: Roles in Health and Disease"
2740:
2522:
403:
1695:"Progressive resistance strength training for improving physical function in older adults"
291:
which help to regenerate skeletal muscle fibers, specifically in "fast twitch" myofibers.
83:, medications, or a wide range of injuries or diseases that impact the musculoskeletal or
8:
2798:
2728:
2664:
2304:
314:
Muscle atrophy from intristic disease in an 18-year-old woman, weight 27 pounds (12.2 kg)
76:
2219:
2192:
1061:
1034:
2772:
2703:
2654:
2578:
2558:
2132:
1903:
1878:
1859:
1804:
1779:
1719:
1694:
1574:
1523:
1498:
1433:
1406:
1387:
1339:
1314:
1290:
1263:
1239:
1214:
1190:
1165:
1015:
928:
885:
839:
643:
638:
633:
514:
486:
358:
330:
120:
112:
104:
103:
muscle atrophy and can be slowed by exercise. Finally, diseases of the muscles such as
2532:
2309:
1562:
2776:
2588:
2375:
2326:
2224:
2173:
2094:
2059:
2044:
Comparative
Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology
2019:
1981:
1946:
1908:
1851:
1809:
1755:
1724:
1675:
1632:
1609:
1566:
1528:
1479:
1469:
1438:
1379:
1344:
1295:
1244:
1195:
1146:
1105:
1066:
1019:
1007:
969:
932:
920:
877:
831:
827:
793:
770:
Argilés JM, Campos N, Lopez-Pedrosa JM, Rueda R, Rodriguez-Mañas L (September 2016).
735:
725:
694:
55:
2136:
1863:
1829:"Muscle wasting and aging: Experimental models, fatty infiltrations, and prevention"
1578:
1391:
889:
843:
2547:
2214:
2204:
2163:
2124:
2086:
2051:
2011:
1973:
1938:
1898:
1890:
1843:
1799:
1791:
1747:
1714:
1710:
1706:
1665:
1601:
1558:
1518:
1510:
1461:
1428:
1418:
1371:
1334:
1326:
1313:
Verschuren O, Smorenburg AR, Luiking Y, Bell K, Barber L, Peterson MD (June 2018).
1285:
1275:
1234:
1226:
1185:
1177:
1136:
1097:
1056:
1046:
999:
959:
912:
869:
823:
783:
717:
684:
563:
534:
462:
can be used. These syndromes can also be identified with screening questionnaires.
136:
2168:
2151:
1942:
2823:
2757:
2573:
2487:
2320:
1514:
1375:
1230:
721:
628:
302:
for sarcopenia was released, contributing to its acceptance as a disease entity.
288:
284:
280:
72:
1465:
1141:
1124:
788:
771:
2687:
2649:
2568:
2517:
2492:
2470:
2331:
2090:
2055:
2015:
1605:
1129:
The
Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
1101:
1051:
916:
407:
366:
218:
84:
2294:
1847:
873:
2792:
2676:
2593:
1003:
522:
214:
135:
the underlying cause but will often include exercise and adequate nutrition.
1751:
1670:
1653:
964:
947:
689:
672:
2634:
2446:
2424:
2228:
2177:
2098:
2063:
2023:
1985:
1950:
1912:
1855:
1813:
1728:
1679:
1613:
1570:
1532:
1483:
1442:
1383:
1348:
1299:
1280:
1248:
1199:
1150:
1109:
1070:
1011:
973:
924:
881:
797:
739:
698:
546:
538:
194:
80:
2209:
1795:
835:
2768:
2583:
2552:
2459:
2350:
1744:
Functional electrical stimulation in rehabilitation engineering: A survey
583:
391:
322:
Muscle atrophy from intristic disease in a 17-year-old girl with chronic
217:, etc.), deinnervation, intrinsic muscle disease or medications (such as
2277:
2712:
2693:
2617:
2612:
2501:
1977:
1894:
1423:
1330:
1181:
613:
518:
455:
443:
435:
323:
276:
170:
108:
96:
1213:
Powers SK, Lynch GS, Murphy KT, Reid MB, Zijdewind I (November 2016).
545:, is being investigated with promising results. They would have fewer
238:
Certain diseases can cause a complex muscle wasting syndrome known as
111:
can cause atrophy, as well as damage to the nervous system such as in
2708:
1592:
Sandri M (June 2008). "Signaling in muscle atrophy and hypertrophy".
465:
Muscle mass and changes can be quantified on imaging studies such as
439:
431:
260:
178:
493:
who cannot exercise due to physical limitations such as paraplegia,
123:) in a disease rather than being a disease by itself. However, some
2683:
2671:
2659:
2639:
2563:
2454:
2399:
2001:
618:
559:
489:
or slow muscle breakdown as well as optimizing nutritional status.
459:
338:
295:
264:
239:
186:
174:
124:
92:
2608:
2538:
Inappropriate rapid heart rate response to exercise (tachycardia)
2419:
2114:
510:
310:
190:
161:
87:. Muscle atrophy leads to muscle weakness and causes disability.
2603:
2403:
2289:
2246:
1312:
769:
591:
354:
198:
116:
100:
42:
2397:
1773:
1771:
2644:
2466:
1264:"Skeletal muscle mitochondrial health and spinal cord injury"
1090:
American
Journal of Physiology. Endocrinology and Metabolism
2411:
2129:
10.1644/1545-1542(2004)085<0414:BSTOHB>2.0.CO;2
1768:
578:
474:
255:
210:
1455:
1404:
816:
The Journal of Steroid Biochemistry and Molecular Biology
1548:
1163:
902:
1826:
1827:
Brioche T, Pagano AF, Py G, Chopard A (August 2016).
1742:
Zhang D, Guan TH, Widjaja F, Ang WT (23 April 2007).
1499:"Signaling pathways controlling skeletal muscle mass"
1215:"Disease-Induced Skeletal Muscle Atrophy and Fatigue"
1212:
1164:
Anker SD, Morley JE, von Haehling S (December 2016).
776:
Journal of the American Medical Directors Association
2267:
1741:
1125:"Sarcopenia: causes, consequences, and preventions"
533:In severe cases of muscular atrophy, the use of an
372:
2076:
948:"Cachexia: pathophysiology and clinical relevance"
945:
1261:
859:
497:can be used to externally stimulate the muscles.
2790:
2041:
348:
2037:
2035:
2033:
1997:
1995:
946:Morley JE, Thomas DR, Wilson MM (April 2006).
711:
2383:
1361:
989:
809:
807:
169:Skeletal muscle serves as a storage site for
119:. Thus, muscle atrophy is usually a finding (
2149:
2070:
2030:
1992:
1928:
1627:Bishop J, Briony T (2007). "Section 1.9.2".
1626:
1585:
1496:
1490:
305:
1963:
1699:The Cochrane Database of Systematic Reviews
1219:Medicine and Science in Sports and Exercise
1166:"Welcome to the ICD-10 code for sarcopenia"
855:
853:
2390:
2376:
1883:Journal of Cachexia, Sarcopenia and Muscle
1319:Journal of Cachexia, Sarcopenia and Muscle
1170:Journal of Cachexia, Sarcopenia and Muscle
952:The American Journal of Clinical Nutrition
804:
650:Journal of Cachexia, Sarcopenia and Muscle
402:Disorders of the endocrine system such as
41:
2260:at the U.S. National Library of Medicine
2218:
2208:
2167:
2110:
2108:
1902:
1803:
1718:
1692:
1669:
1522:
1432:
1422:
1338:
1289:
1279:
1238:
1189:
1140:
1060:
1050:
963:
787:
688:
1777:
850:
673:"Measuring cachexia-diagnostic criteria"
317:
309:
160:
2190:
1876:
1122:
1083:
1032:
624:Effect of spaceflight on the human body
298:although they may co-exist. In 2016 an
14:
2791:
2105:
1931:Archives of Gerontology and Geriatrics
1591:
1262:O'Brien LC, Gorgey AS (October 2016).
597:
543:selective androgen receptor modulators
369:can cause generalized muscle atrophy.
2734:Fibrodysplasia ossificans progressiva
2371:
1924:
1922:
1651:
1551:Current Protein & Peptide Science
1544:
1542:
1497:Egerman MA, Glass DJ (Jan–Feb 2014).
813:
248:chronic obstructive pulmonary disease
207:chronic obstructive pulmonary disease
143:
985:
983:
765:
763:
761:
759:
757:
755:
753:
751:
749:
361:. More widespread damage such as in
165:Muscle atrophy from "nondevelopment"
61:Physical medicine and rehabilitation
2533:Dynamic symptoms (exercise-induced)
670:
410:are known to cause muscle atrophy.
397:
24:
1919:
1539:
1364:Plastic and Reconstructive Surgery
413:
25:
2845:
2239:
1563:10.2174/1389203720666190402100902
980:
746:
495:functional electrical stimulation
242:. It is commonly seen in cancer,
2245:
569:
471:Magnetic resonance imaging (MRI)
442:which allows recognition by the
373:Peripheral nervous system damage
2184:
2143:
1957:
1870:
1820:
1735:
1693:Liu CJ, Latham NK (July 2009).
1686:
1645:
1631:. Wiley-Blackwell. p. 76.
1620:
1449:
1398:
1355:
1306:
1255:
1206:
1157:
1116:
1077:
140:critical in injury or illness.
2150:van den Hoek A (August 2019).
1711:10.1002/14651858.CD002759.pub2
1026:
992:Nutrition in Clinical Practice
939:
896:
705:
664:
385:
13:
1:
2169:10.1016/j.metabol.2019.05.012
1943:10.1016/j.archger.2015.06.020
1836:Molecular Aspects of Medicine
677:Annals of Palliative Medicine
657:
349:Central nervous system damage
335:amyotrophic lateral sclerosis
281:type I skeletal muscle fibers
271:
224:
197:, certain systemic diseases (
193:, include immobility, aging,
1600:(3). Bethesda, Md.: 160–70.
1515:10.3109/10409238.2013.857291
1376:10.1097/PRS.0000000000005370
1268:World Journal of Orthopedics
1231:10.1249/MSS.0000000000000975
828:10.1016/0960-0760(94)90165-1
722:10.1007/978-981-13-1435-3_23
527:randomized controlled trials
480:
449:
27:Loss of skeletal muscle mass
7:
1629:Manual of Dietetic Practice
1466:10.1007/978-981-13-1435-3_9
1123:Marcell TJ (October 2003).
1033:de Jong J (February 2023).
789:10.1016/j.jamda.2016.04.019
606:
552:
473:. Biomarkers such as urine
380:Charcot-Marie-Tooth disease
233:
10:
2850:
2091:10.1152/physrev.00008.2003
2056:10.1016/j.cbpb.2006.12.020
2016:10.1016/j.clnu.2007.07.003
1652:Sayer AA (November 2014).
1606:10.1152/physiol.00041.2007
1102:10.1152/ajpendo.00278.2006
1084:Verdijk L (January 2007).
1052:10.1007/s11357-023-00750-4
917:10.1016/j.clnu.2008.06.013
507:β-Hydroxy β-methylbutyrate
503:branched-chain amino acids
345:can cause muscle atrophy.
75:mass. It can be caused by
2809:Complications of diabetes
2765:Pseudoathletic appearance
2721:
2627:
2599:Intermittent claudication
2510:
2480:
2445:
2410:
2341:
2271:
1877:HoleÄŤek M (August 2017).
1848:10.1016/j.mam.2016.04.006
1778:Phillips SM (July 2015).
1503:Crit Rev Biochem Mol Biol
1142:10.1093/gerona/58.10.m911
874:10.1016/j.arr.2013.07.003
329:Muscle diseases, such as
306:Intrinsic muscle diseases
156:
129:spinal muscular atrophies
54:
49:
40:
35:
2834:External signs of ageing
2262:Medical Subject Headings
1004:10.1177/0884533616680354
446:to degrade the protein.
244:congestive heart failure
203:congestive heart failure
2819:Rehabilitation medicine
2699:Rippling muscle disease
2191:de Jong J (June 2023).
1752:10.1145/1328491.1328546
862:Ageing Research Reviews
690:10.21037/apm.2018.08.07
509:(HMB), a metabolite of
343:inclusion body myositis
2677:Muscle channelopathies
2528:Myogenic hyperuricemia
1281:10.5312/wjo.v7.i10.628
671:Dev R (January 2019).
363:traumatic brain injury
326:
315:
283:over "fast twitch" or
252:chronic kidney disease
183:adenosine triphosphate
166:
2574:Hyperthyroid myopathy
2210:10.14336/AD.2022.1201
2199:(Original Research).
2158:(Original Research).
2079:Physiological Reviews
1796:10.3945/an.115.008367
1784:Advances in Nutrition
1671:10.1093/ageing/afu118
1092:(Original Research).
1041:(Original Research).
965:10.1093/ajcn/83.4.735
321:
313:
164:
2741:Compartment syndrome
2569:Hypothyroid myopathy
2559:Metabolic myopathies
2523:Exercise intolerance
2471:Hypothyroid myopathy
2254:at Wikimedia Commons
2117:Journal of Mammalogy
2753:Diastasis of muscle
2729:Myositis ossificans
598:Pre-clinical models
513:which is sold as a
189:. Causes of muscle
2829:Muscular disorders
2773:Muscle hypertrophy
2769:Muscle hyperplasia
2704:Periodic paralysis
2655:Muscle contracture
2579:Hypoparathyroidism
2342:External resources
2004:Clinical Nutrition
1978:10.2217/fon.13.273
1895:10.1002/jcsm.12208
1424:10.1111/apha.13400
1331:10.1002/jcsm.12287
1182:10.1002/jcsm.12147
905:Clinical Nutrition
644:Myotonic dystrophy
639:Muscle hypertrophy
634:Muscular dystrophy
539:methandrostenolone
515:dietary supplement
487:muscle hypertrophy
359:spinal cord injury
331:muscular dystrophy
327:
316:
167:
144:Signs and symptoms
113:spinal cord injury
105:muscular dystrophy
2786:
2785:
2777:Pseudohypertrophy
2628:Abnormal movement
2511:Low ATP reservoir
2365:
2364:
2250:Media related to
2197:Aging and Disease
1761:978-1-59593-852-7
1638:978-1-4051-3525-2
1411:Acta Physiologica
1225:(11): 2307–2319.
404:Cushing's disease
66:
65:
30:Medical condition
16:(Redirected from
2841:
2548:Hitting the wall
2392:
2385:
2378:
2369:
2368:
2269:
2268:
2258:Muscular atrophy
2249:
2233:
2232:
2222:
2212:
2188:
2182:
2181:
2171:
2147:
2141:
2140:
2112:
2103:
2102:
2074:
2068:
2067:
2039:
2028:
2027:
1999:
1990:
1989:
1961:
1955:
1954:
1926:
1917:
1916:
1906:
1874:
1868:
1867:
1833:
1824:
1818:
1817:
1807:
1775:
1766:
1765:
1739:
1733:
1732:
1722:
1690:
1684:
1683:
1673:
1649:
1643:
1642:
1624:
1618:
1617:
1589:
1583:
1582:
1546:
1537:
1536:
1526:
1494:
1488:
1487:
1453:
1447:
1446:
1436:
1426:
1402:
1396:
1395:
1359:
1353:
1352:
1342:
1310:
1304:
1303:
1293:
1283:
1259:
1253:
1252:
1242:
1210:
1204:
1203:
1193:
1161:
1155:
1154:
1144:
1120:
1114:
1113:
1096:(1): E151–E157.
1081:
1075:
1074:
1064:
1054:
1045:(4): 2367–2386.
1030:
1024:
1023:
987:
978:
977:
967:
943:
937:
936:
900:
894:
893:
857:
848:
847:
811:
802:
801:
791:
767:
744:
743:
709:
703:
702:
692:
668:
564:frailty syndrome
535:anabolic steroid
398:Endocrinopathies
45:
33:
32:
21:
18:Muscular atrophy
2849:
2848:
2844:
2843:
2842:
2840:
2839:
2838:
2814:Gross pathology
2789:
2788:
2787:
2782:
2758:Diastasis recti
2717:
2684:Pseudo-myotonia
2623:
2506:
2488:Muscle weakness
2476:
2441:
2406:
2396:
2366:
2361:
2360:
2337:
2336:
2280:
2242:
2237:
2236:
2189:
2185:
2148:
2144:
2113:
2106:
2075:
2071:
2040:
2031:
2000:
1993:
1966:Future Oncology
1962:
1958:
1927:
1920:
1875:
1871:
1831:
1825:
1821:
1776:
1769:
1762:
1740:
1736:
1705:(3): CD002759.
1691:
1687:
1650:
1646:
1639:
1625:
1621:
1590:
1586:
1547:
1540:
1495:
1491:
1476:
1454:
1450:
1403:
1399:
1360:
1356:
1311:
1307:
1274:(10): 628–637.
1260:
1256:
1211:
1207:
1162:
1158:
1121:
1117:
1082:
1078:
1031:
1027:
988:
981:
944:
940:
901:
897:
858:
851:
812:
805:
768:
747:
732:
710:
706:
669:
665:
660:
655:
629:Muscle weakness
609:
600:
572:
555:
521:. Based upon a
483:
452:
416:
414:Pathophysiology
400:
388:
375:
351:
308:
289:satellite cells
274:
236:
227:
219:glucocorticoids
159:
146:
137:Anabolic agents
121:sign or symptom
73:skeletal muscle
71:is the loss of
31:
28:
23:
22:
15:
12:
11:
5:
2847:
2837:
2836:
2831:
2826:
2821:
2816:
2811:
2806:
2801:
2784:
2783:
2781:
2780:
2762:
2761:
2760:
2750:
2749:
2748:
2738:
2737:
2736:
2725:
2723:
2719:
2718:
2716:
2715:
2706:
2701:
2696:
2691:
2688:Brody myopathy
2681:
2680:
2679:
2669:
2668:
2667:
2662:
2652:
2650:Fasciculations
2647:
2642:
2637:
2631:
2629:
2625:
2624:
2622:
2621:
2615:
2606:
2601:
2596:
2591:
2589:Hypoxic muscle
2586:
2581:
2576:
2571:
2566:
2561:
2555:
2550:
2545:
2540:
2535:
2530:
2525:
2520:
2518:Muscle fatigue
2514:
2512:
2508:
2507:
2505:
2504:
2498:Muscle atrophy
2495:
2493:Rhabdomyolysis
2490:
2484:
2482:
2478:
2477:
2475:
2474:
2464:
2463:
2462:
2451:
2449:
2443:
2442:
2440:
2439:
2438:
2437:
2432:
2427:
2416:
2414:
2408:
2407:
2395:
2394:
2387:
2380:
2372:
2363:
2362:
2359:
2358:
2346:
2345:
2343:
2339:
2338:
2335:
2334:
2323:
2312:
2297:
2281:
2276:
2275:
2273:
2272:Classification
2266:
2265:
2255:
2252:Muscle atrophy
2241:
2240:External links
2238:
2235:
2234:
2203:(3): 937–957.
2183:
2142:
2123:(3): 414–419.
2104:
2085:(4): 1153–81.
2069:
2029:
1991:
1956:
1918:
1889:(4): 529–541.
1869:
1819:
1767:
1760:
1734:
1685:
1658:Age and Ageing
1644:
1637:
1619:
1584:
1557:(6): 536–546.
1538:
1489:
1474:
1458:Muscle Atrophy
1448:
1397:
1370:(3): 779–788.
1354:
1325:(3): 453–464.
1305:
1254:
1205:
1176:(5): 512–514.
1156:
1135:(10): M911-6.
1115:
1076:
1025:
979:
938:
895:
868:(4): 898–906.
849:
803:
745:
730:
714:Muscle Atrophy
704:
662:
661:
659:
656:
654:
653:
646:
641:
636:
631:
626:
621:
616:
610:
608:
605:
599:
596:
571:
568:
554:
551:
482:
479:
451:
448:
415:
412:
408:hypothyroidism
399:
396:
387:
384:
374:
371:
367:cerebral palsy
350:
347:
307:
304:
285:type II fibers
273:
270:
235:
232:
226:
223:
158:
155:
145:
142:
85:nervous system
69:Muscle atrophy
64:
63:
58:
52:
51:
47:
46:
38:
37:
36:Muscle atrophy
29:
26:
9:
6:
4:
3:
2:
2846:
2835:
2832:
2830:
2827:
2825:
2822:
2820:
2817:
2815:
2812:
2810:
2807:
2805:
2804:Medical signs
2802:
2800:
2797:
2796:
2794:
2778:
2774:
2770:
2766:
2763:
2759:
2756:
2755:
2754:
2751:
2747:
2744:
2743:
2742:
2739:
2735:
2732:
2731:
2730:
2727:
2726:
2724:
2720:
2714:
2710:
2707:
2705:
2702:
2700:
2697:
2695:
2692:
2689:
2685:
2682:
2678:
2675:
2674:
2673:
2670:
2666:
2663:
2661:
2658:
2657:
2656:
2653:
2651:
2648:
2646:
2643:
2641:
2638:
2636:
2633:
2632:
2630:
2626:
2619:
2616:
2614:
2610:
2607:
2605:
2602:
2600:
2597:
2595:
2594:Pseudohypoxia
2592:
2590:
2587:
2585:
2582:
2580:
2577:
2575:
2572:
2570:
2567:
2565:
2562:
2560:
2556:
2554:
2551:
2549:
2546:
2544:
2541:
2539:
2536:
2534:
2531:
2529:
2526:
2524:
2521:
2519:
2516:
2515:
2513:
2509:
2503:
2499:
2496:
2494:
2491:
2489:
2486:
2485:
2483:
2479:
2472:
2468:
2465:
2461:
2458:
2457:
2456:
2453:
2452:
2450:
2448:
2444:
2436:
2435:Delayed onset
2433:
2431:
2428:
2426:
2423:
2422:
2421:
2418:
2417:
2415:
2413:
2409:
2405:
2401:
2398:Symptoms and
2393:
2388:
2386:
2381:
2379:
2374:
2373:
2370:
2357:
2353:
2352:
2348:
2347:
2344:
2340:
2333:
2329:
2328:
2324:
2322:
2318:
2317:
2313:
2311:
2307:
2306:
2302:
2298:
2296:
2292:
2291:
2287:
2283:
2282:
2279:
2274:
2270:
2263:
2259:
2256:
2253:
2248:
2244:
2243:
2230:
2226:
2221:
2216:
2211:
2206:
2202:
2198:
2194:
2187:
2179:
2175:
2170:
2165:
2161:
2157:
2153:
2146:
2138:
2134:
2130:
2126:
2122:
2118:
2111:
2109:
2100:
2096:
2092:
2088:
2084:
2080:
2073:
2065:
2061:
2057:
2053:
2049:
2045:
2038:
2036:
2034:
2025:
2021:
2017:
2013:
2010:(5): 658–61.
2009:
2005:
1998:
1996:
1987:
1983:
1979:
1975:
1972:(2): 187–94.
1971:
1967:
1960:
1952:
1948:
1944:
1940:
1937:(2): 168–75.
1936:
1932:
1925:
1923:
1914:
1910:
1905:
1900:
1896:
1892:
1888:
1884:
1880:
1873:
1865:
1861:
1857:
1853:
1849:
1845:
1841:
1837:
1830:
1823:
1815:
1811:
1806:
1801:
1797:
1793:
1790:(4): 452–60.
1789:
1785:
1781:
1774:
1772:
1763:
1757:
1753:
1749:
1745:
1738:
1730:
1726:
1721:
1716:
1712:
1708:
1704:
1700:
1696:
1689:
1681:
1677:
1672:
1667:
1663:
1659:
1655:
1648:
1640:
1634:
1630:
1623:
1615:
1611:
1607:
1603:
1599:
1595:
1588:
1580:
1576:
1572:
1568:
1564:
1560:
1556:
1552:
1545:
1543:
1534:
1530:
1525:
1520:
1516:
1512:
1508:
1504:
1500:
1493:
1485:
1481:
1477:
1475:9789811314346
1471:
1467:
1463:
1459:
1452:
1444:
1440:
1435:
1430:
1425:
1420:
1417:(2): e13400.
1416:
1412:
1408:
1401:
1393:
1389:
1385:
1381:
1377:
1373:
1369:
1365:
1358:
1350:
1346:
1341:
1336:
1332:
1328:
1324:
1320:
1316:
1309:
1301:
1297:
1292:
1287:
1282:
1277:
1273:
1269:
1265:
1258:
1250:
1246:
1241:
1236:
1232:
1228:
1224:
1220:
1216:
1209:
1201:
1197:
1192:
1187:
1183:
1179:
1175:
1171:
1167:
1160:
1152:
1148:
1143:
1138:
1134:
1130:
1126:
1119:
1111:
1107:
1103:
1099:
1095:
1091:
1087:
1080:
1072:
1068:
1063:
1058:
1053:
1048:
1044:
1040:
1036:
1029:
1021:
1017:
1013:
1009:
1005:
1001:
997:
993:
986:
984:
975:
971:
966:
961:
958:(4): 735–43.
957:
953:
949:
942:
934:
930:
926:
922:
918:
914:
910:
906:
899:
891:
887:
883:
879:
875:
871:
867:
863:
856:
854:
845:
841:
837:
833:
829:
825:
821:
817:
810:
808:
799:
795:
790:
785:
782:(9): 789–96.
781:
777:
773:
766:
764:
762:
760:
758:
756:
754:
752:
750:
741:
737:
733:
731:9789811314346
727:
723:
719:
715:
708:
700:
696:
691:
686:
682:
678:
674:
667:
663:
652:
651:
647:
645:
642:
640:
637:
635:
632:
630:
627:
625:
622:
620:
617:
615:
612:
611:
604:
595:
593:
587:
585:
580:
576:
570:Other animals
567:
565:
561:
550:
548:
544:
540:
536:
531:
528:
524:
523:meta-analysis
520:
516:
512:
508:
504:
498:
496:
490:
488:
478:
476:
472:
468:
463:
461:
457:
447:
445:
441:
437:
433:
429:
424:
420:
411:
409:
405:
395:
393:
383:
381:
370:
368:
364:
360:
356:
346:
344:
340:
336:
332:
325:
320:
312:
303:
301:
297:
292:
290:
286:
282:
278:
269:
266:
262:
257:
253:
249:
245:
241:
231:
222:
220:
216:
215:liver disease
212:
208:
204:
200:
196:
192:
188:
184:
180:
176:
172:
163:
154:
150:
141:
138:
132:
130:
126:
122:
118:
114:
110:
106:
102:
98:
94:
88:
86:
82:
78:
74:
70:
62:
59:
57:
53:
48:
44:
39:
34:
19:
2645:Muscle spasm
2635:Muscle cramp
2497:
2447:Inflammation
2425:Fibromyalgia
2402:relating to
2349:
2325:
2314:
2299:
2284:
2200:
2196:
2186:
2159:
2155:
2145:
2120:
2116:
2082:
2078:
2072:
2047:
2043:
2007:
2003:
1969:
1965:
1959:
1934:
1930:
1886:
1882:
1872:
1839:
1835:
1822:
1787:
1783:
1743:
1737:
1702:
1698:
1688:
1664:(6): 736–7.
1661:
1657:
1647:
1628:
1622:
1597:
1593:
1587:
1554:
1550:
1509:(1): 59–68.
1506:
1502:
1492:
1457:
1451:
1414:
1410:
1400:
1367:
1363:
1357:
1322:
1318:
1308:
1271:
1267:
1257:
1222:
1218:
1208:
1173:
1169:
1159:
1132:
1128:
1118:
1093:
1089:
1079:
1042:
1038:
1028:
998:(1): 30–39.
995:
991:
955:
951:
941:
911:(6): 793–9.
908:
904:
898:
865:
861:
822:(1–2): 1–4.
819:
815:
779:
775:
713:
707:
683:(1): 24–32.
680:
676:
666:
648:
601:
588:
577:
573:
556:
547:side effects
532:
499:
491:
484:
464:
453:
425:
421:
417:
401:
389:
376:
352:
328:
293:
275:
237:
228:
195:malnutrition
168:
151:
147:
133:
89:
81:malnutrition
68:
67:
2584:Hypokalemia
2553:Second wind
2481:Destruction
2460:Pyomyositis
2351:MedlinePlus
2050:(1): 20–8.
1039:GeroScience
584:hibernation
430:-dependent
392:doxorubicin
386:Medications
171:amino acids
101:age-related
2799:Physiology
2793:Categories
2713:Hypertonia
2694:Spasticity
2618:Alcoholism
2613:Starvation
2502:Amyotrophy
2400:conditions
2327:DiseasesDB
2156:Metabolism
1594:Physiology
658:References
614:Sarcopenia
519:sarcopenia
456:sarcopenia
444:proteasome
436:proteasome
337:(ALS), or
324:rheumatism
277:Sarcopenia
272:Sarcopenia
225:Immobility
109:myopathies
97:Sarcopenia
77:immobility
2709:Hypotonia
2162:: 57–67.
1842:: 56–87.
1020:206555460
933:206821612
525:of seven
481:Treatment
450:Diagnosis
440:ubiquitin
432:ubiquitin
261:cytokines
179:myoglobin
125:syndromes
79:, aging,
56:Specialty
2746:Anterior
2672:Myotonia
2665:Adhesion
2660:Fibrosis
2640:Myokymia
2564:Diabetes
2467:Myoedema
2455:Myositis
2229:37191430
2220:10187708
2178:31153978
2137:86315375
2099:14506303
2064:17307375
2024:17904252
1986:24490605
1951:26169182
1913:28493406
1864:29717535
1856:27106402
1814:26178029
1729:19588334
1680:25227204
1614:18556469
1579:96434115
1571:30947668
1533:24237131
1484:30390253
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1392:73495244
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560:cachexia
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