The effect of unloading on protein synthesis in human skeletal muscle

GAMRIN,; BERG,; ESSEN,; TESCH,; HULTMAN,; GARLICK,; McNURLAN,; WERNERMAN,

doi:10.1046/j.1365-201x.1998.00391.x

Cited by 14 publications

(19 citation statements)

References 20 publications

(26 reference statements)

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“…ULLS studies of shorter duration (10-21 days) found KE MVC decreased by ϳ12-17% (2,11,32,84). Longer ULLS studies of 28, 35, and 42 days have each reported that the MVC of the KE decreased by ϳ20% (8,23,76,77).…”

Section: Muscle Strength Measurements After Ullsmentioning

confidence: 91%

Skeletal muscle unweighting: spaceflight and ground-based models

Adams¹,

Caiozzo²,

Baldwin³

2003

Journal of Applied Physiology

320

285

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Long-term manned spaceflight requires that flight crews be exposed to extended periods of unweighting of antigravity skeletal muscles. This exposure will result in adaptations in these muscles that have the potential to debilitate crew members on return to increased gravity environments. Therefore, the development of countermeasures to prevent these unwanted adaptations is an important requirement. The limited access to microgravity environments for the purpose of studying muscle adaptation and evaluating countermeasure programs has necessitated the use of ground-based models to conduct both basic and applied muscle physiology research. In this review, the published results from ground-based models of muscle unweighting are presented and compared with the results from related spaceflight research. The models of skeletal muscle unweighting with a sufficient body of literature included bed rest, cast immobilization, and unilateral lower limb suspension. Comparisons of changes in muscle strength and size between these models in the context of the limited results available from spaceflight suggest that each model may be useful for the investigation of certain aspects of the skeletal muscle unweighting that occur in microgravity.

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Section: Muscle Strength Measurements After Ullsmentioning

confidence: 91%

Skeletal muscle unweighting: spaceflight and ground-based models

Adams¹,

Caiozzo²,

Baldwin³

2003

Journal of Applied Physiology

320

285

View full text Add to dashboard Cite

show abstract

“…In vivo, there was *10% decline in the fractional rate of muscle protein synthesis after 10 days of ULLS (Gamrin et al 1998) and *50% reduction after 14 days of bed rest (Ferrando et al 1996). Moreover, de Boer et al (2007b) suggest that the greatest drop in the rate of muscle protein occurs initially (*10 days) with little change as unloading persists (*21 days).…”

Section: Reduced Protein Synthesismentioning

confidence: 95%

Unilateral lower limb suspension: integrative physiological knowledge from the past 20 years (1991–2011)

Hackney

Ploutz‐Snyder

2011

Eur J Appl Physiol

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In 1991, Hans Berg and colleagues published the first research investigation using unilateral lower limb suspension (ULLS) as a human model to study the influence of unloading on skeletal muscle. ULLS requires a participant to perform all activities with axillary crutches while wearing one thick-soled shoe. The elevated shoe eliminates ground contact with the adjacent foot, thereby unloading the lower limb. Today, ULLS is a well-known ground-based analog for microgravity. The present review will synthesize the physiological findings from investigations using ULLS to study the deleterious effects of unloading. Compromised human performance and the neuromuscular, musculoskeletal and circulatory mechanisms leading to altered function will be a major emphasis of the work. Results from prolonged bed rest will also be included in order for general comparisons to be made between analogs. Finally, the efficacy of exercise to mitigate the negative consequences of unloading is presented.

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“…The loss of muscle mass observed in actual and simulated microgravity is the result of a disruption in the balance between protein synthesis and breakdown (Gamrin et al 1998). A reduction in muscle protein anabolism has indeed been observed in both animal and human models following immobilization (Gibson et al 1987), and actual spaceflight (Ferrando et al 2002).…”

Section: Protein Synthesis and Breakdownmentioning

confidence: 97%

Disuse of the musculo-skeletal system in space and on earth

2010

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Muscle mass and strength are well known to decline in response to actual and simulated microgravity exposure. However, despite the considerable knowledge gained on the physiological changes induced by spaceflight, the mechanisms of muscle atrophy and the effectiveness of in-flight countermeasures still need to be fully elucidated. The present review examines the effects and mechanisms of actual and simulated microgravity on single fibre and whole muscle structural and functional properties, protein metabolism, tendon mechanical properties, neural drive and reflex excitability. The effects of inflight countermeasures are also discussed in the light of recent advances in resistive loading techniques, in combined physical, pharmacological and nutritional interventions as well as in the development of artificial gravity systems. Emphasis has been given to the pioneering work of Pietro Enrico di Prampero in the development of artificial gravity systems and in the progress of knowledge on the limits of human muscular performance in space.

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The effect of unloading on protein synthesis in human skeletal muscle

Cited by 14 publications

References 20 publications

Skeletal muscle unweighting: spaceflight and ground-based models

Skeletal muscle unweighting: spaceflight and ground-based models

Unilateral lower limb suspension: integrative physiological knowledge from the past 20 years (1991–2011)

Disuse of the musculo-skeletal system in space and on earth

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