ArticleAmerican journal of physiology. Regulatory, integrative and comparative physiology2014
Human skeletal muscle metabolic economy in vivo: effects of contraction intensity, age, and mobility impairment.
Article in American journal of physiology. Regulatory, integrative and comparative physiology, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 13 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
13 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Pooled it
- Mechanisms underlying age-related changes in the human skeletal muscle bioenergetic system.European journal of applied physiology · 2026Article
- Postcontraction [acetylcarnitine] reflects interindividual variation in skeletal muscle ATP production patterns in vivo.American journal of physiology. Regulatory, integrative and comparative physiology · 2024Article
- Human skeletal muscle-specific atrophy with aging: a comprehensive review.Journal of applied physiology (Bethesda, Md. : 1985) · 2023Review
- Age-related changes in gait biomechanics and their impact on the metabolic cost of walking: Report from a National Institute on Aging workshop.Experimental gerontology · 2023Review
- Matrisome, innervation and oxidative metabolism affected in older compared with younger males with similar physical activity.Journal of cachexia, sarcopenia and muscle · 2021Article
- In vivo assessment of mitochondrial capacity using NIRS in locomotor muscles of young and elderly males with similar physical activity levels.GeroScience · 2020Article
- Impaired Muscle Efficiency but Preserved Peripheral Hemodynamics and Mitochondrial Function With Advancing Age: Evidence From Exercise in the Young, Old, and Oldest-Old.The journals of gerontology. Series A, Biological sciences and medical sciences · 2018Article
- Predictive neuromechanical simulations indicate why walking performance declines with ageing.The Journal of physiology · 2018Article
- Mechanisms of in vivo muscle fatigue in humans: investigating age-related fatigue resistance with a computational model.The Journal of physiology · 2016Article
- Innervation and neuromuscular control in ageing skeletal muscle.The Journal of physiology · 2016Review
- Impact of age on exercise-induced ATP supply during supramaximal plantar flexion in humans.American journal of physiology. Regulatory, integrative and comparative physiology · 2015Article
- Older men are more fatigable than young when matched for maximal power and knee extension angular velocity is unconstrained.Age (Dordrecht, Netherlands) · 2015Article
Corrections and comments
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Authors and funding
5 authors.
Funding
Abstract
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.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.