| Muscle metabolism and acid-base status during exercise in forearm work-related myalgia measured with 31P-MRS. | |
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MedLine Citation:
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PMID: 19112160 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In this study, we examined muscle metabolic and acid-base status during incremental wrist extension exercise in the forearm of individuals with work-related myalgia (WRM). Eighteen women employed in full-time occupations involving repetitive forearm labor were recruited in this cross-sectional study. Nine of these women were diagnosed with WRM, while the other nine had no previous WRM history and were used as age-matched controls (Con). Phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) was used to noninvasively monitor the intracellular concentrations of phosphocreatine ([PCr]) and inorganic phosphate ([P(i)]) as well as intracellular pH (pH(i)) status during exercise in WRM and Con. We observed a 38% decreased work capacity in WRM compared with Con [0.18 W (SD 0.03) vs. 0.28 W (SD 0.10); P = 0.007]. Piecewise linear regression of the incremental exercise data revealed that the onset of a faster decrease in pH(i) (i.e., the pH threshold, pHT) and the onset of a faster increase in log([P(i)]/[PCr]) (i.e., the phosphorylation threshold, PT) occurred at a 14% relatively lower power output in WRM [pHT: 45.2% (SD 5.3) vs. 59.0% (SD 4.6), P < 0.001; PT: 44.8% (SD 4.3) vs. 57.8% (SD 3.1), P < 0.001; % of peak power output, Con vs. WRM, respectively]. Monoexponential modeling of the kinetics of [PCr] and pH(i) recovery following exercise demonstrated a slower (P = 0.005) time constant (tau) for [PCr] in WRM [113 s (SD 25)] vs. Con [77 s (SD 23)] and a slower (P = 0.007) tau for pH(i) in WRM [370 s (SD 178)] vs. Con [179 s (SD 52)]. In conclusion, our results suggest that WRM is associated with an increased reliance on nonoxidative metabolism. Possible mechanisms include a reduction in local muscle blood flow and perfusion, an increased ATP cost of force production, or both. |
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Authors:
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Graydon H Raymer; Howard J Green; Don A Ranney; Greg D Marsh; R Terry Thompson |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2008-12-26 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 106 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2009 Apr |
Date Detail:
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Created Date: 2009-04-01 Completed Date: 2009-05-29 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1198-206 Citation Subset: IM |
Affiliation:
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School of Physical and Health Education, Nipissing University, North Bay, ON, Canada. graydonr@nipissingu.ca |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acid-Base Equilibrium
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physiology* Adult Cross-Sectional Studies Exercise / physiology* Exercise Tolerance / physiology Female Forearm / physiology* Humans Hydrogen-Ion Concentration Magnetic Resonance Imaging Magnetic Resonance Spectroscopy Middle Aged Muscle Fatigue / physiology Muscle Strength / physiology Muscle, Skeletal / anatomy & histology, metabolism* Occupations Pain / etiology, metabolism*, physiopathology Phosphates / metabolism Phosphocreatine / metabolism Phosphorylation |
| Chemical | |
Reg. No./Substance:
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0/Phosphates; 67-07-2/Phosphocreatine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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