Effects of lengthening contraction on calcium kinetics and skeletal muscle contractility in humans.
Saved in:
| Title: | Effects of lengthening contraction on calcium kinetics and skeletal muscle contractility in humans. |
|---|---|
| Authors: | Nielsen, J. S., Madsen, K., JØrgensen, L. V., Sahlin, K. |
| Source: | Acta Physiologica Scandinavica. Jul2005, Vol. 184 Issue 3, p203-214. 12p. |
| Subjects: | Calcium metabolism, Human body, Contractility (Biology), Cell contraction, Biomechanics, Creatine |
| Abstract: | We have tested the hypothesis that the altered muscle contractility after lengthening contractions (LC) is caused by altered calcium (Ca2+) kinetics. Subjects ( n = 8) performed 100 drop jumps and muscle contractility was measured pre- and post-exercise by maximal voluntary contraction (MVC) and transcutaneous electrical stimulation (1, 20 and 50 Hz). Muscle biopsies were analysed for muscle metabolites, rates of SR Ca2+ uptake (CaU) and release (CaR) and myosin heavy chain (MHC) composition. The rates of torque relaxation and CaU were positively related to muscle fibre type composition (% MHC II). Muscle creatine (Cr) decreased and the ratio between phosphocreatine (PCr) and Cr increased 3 and 24 h post-exercise ( P < 0.05 vs. pre-exercise). LC resulted in reduced MVC (−19%), twitch torque (−41%) and 20/50 Hz torque ratio (−30%) and a faster relaxation rate ( P < 0.05). The contractile parameters recovered partially but remained altered 24 h post-exercise ( P < 0.05). The average CaR was unchanged after LC ( P > 0.05). However, the response varied between subjects and the relative post-exercise CaR was significantly related to the degree of LFF (post/pre 20/50 Hz force ratio) and to the decline in twitch force (post/pre twitch ratio). CaU was lower in seven of eight subjects after LC ( P > 0.05). The decline in torque after LC could not be explained by metabolic factors since PCr/Cr ratio increased. The relation between CaR and fatigue suggests that the mechanism of fatigue in part may be attributed to intrinsic changes in the SR Ca2+ release channel. The faster torque relaxation after LC could not be explained by an increased rate of CaU. [ABSTRACT FROM AUTHOR] |
| Copyright of Acta Physiologica Scandinavica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Psychology and Behavioral Sciences Collection |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
|---|---|
| Header | DbId: pbh DbLabel: Psychology and Behavioral Sciences Collection An: 17273635 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
| IllustrationInfo | |
| Items | – Name: Title Label: Title Group: Ti Data: Effects of lengthening contraction on calcium kinetics and skeletal muscle contractility in humans. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Nielsen%2C+J%2E+S%2E%22">Nielsen, J. S.</searchLink><br /><searchLink fieldCode="AR" term="%22Madsen%2C+K%2E%22">Madsen, K.</searchLink><br /><searchLink fieldCode="AR" term="%22JØrgensen%2C+L%2E+V%2E%22">JØrgensen, L. V.</searchLink><br /><searchLink fieldCode="AR" term="%22Sahlin%2C+K%2E%22">Sahlin, K.</searchLink> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Acta+Physiologica+Scandinavica%22">Acta Physiologica Scandinavica</searchLink>. Jul2005, Vol. 184 Issue 3, p203-214. 12p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Calcium+metabolism%22">Calcium metabolism</searchLink><br /><searchLink fieldCode="DE" term="%22Human+body%22">Human body</searchLink><br /><searchLink fieldCode="DE" term="%22Contractility+%28Biology%29%22">Contractility (Biology)</searchLink><br /><searchLink fieldCode="DE" term="%22Cell+contraction%22">Cell contraction</searchLink><br /><searchLink fieldCode="DE" term="%22Biomechanics%22">Biomechanics</searchLink><br /><searchLink fieldCode="DE" term="%22Creatine%22">Creatine</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: We have tested the hypothesis that the altered muscle contractility after lengthening contractions (LC) is caused by altered calcium (Ca2+) kinetics. Subjects ( n = 8) performed 100 drop jumps and muscle contractility was measured pre- and post-exercise by maximal voluntary contraction (MVC) and transcutaneous electrical stimulation (1, 20 and 50 Hz). Muscle biopsies were analysed for muscle metabolites, rates of SR Ca2+ uptake (CaU) and release (CaR) and myosin heavy chain (MHC) composition. The rates of torque relaxation and CaU were positively related to muscle fibre type composition (% MHC II). Muscle creatine (Cr) decreased and the ratio between phosphocreatine (PCr) and Cr increased 3 and 24 h post-exercise ( P < 0.05 vs. pre-exercise). LC resulted in reduced MVC (−19%), twitch torque (−41%) and 20/50 Hz torque ratio (−30%) and a faster relaxation rate ( P < 0.05). The contractile parameters recovered partially but remained altered 24 h post-exercise ( P < 0.05). The average CaR was unchanged after LC ( P > 0.05). However, the response varied between subjects and the relative post-exercise CaR was significantly related to the degree of LFF (post/pre 20/50 Hz force ratio) and to the decline in twitch force (post/pre twitch ratio). CaU was lower in seven of eight subjects after LC ( P > 0.05). The decline in torque after LC could not be explained by metabolic factors since PCr/Cr ratio increased. The relation between CaR and fatigue suggests that the mechanism of fatigue in part may be attributed to intrinsic changes in the SR Ca2+ release channel. The faster torque relaxation after LC could not be explained by an increased rate of CaU. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Acta Physiologica Scandinavica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=pbh&AN=17273635 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1111/j.1365-201X.2005.01449.x Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 12 StartPage: 203 Subjects: – SubjectFull: Calcium metabolism Type: general – SubjectFull: Human body Type: general – SubjectFull: Contractility (Biology) Type: general – SubjectFull: Cell contraction Type: general – SubjectFull: Biomechanics Type: general – SubjectFull: Creatine Type: general Titles: – TitleFull: Effects of lengthening contraction on calcium kinetics and skeletal muscle contractility in humans. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Nielsen, J. S. – PersonEntity: Name: NameFull: Madsen, K. – PersonEntity: Name: NameFull: JØrgensen, L. V. – PersonEntity: Name: NameFull: Sahlin, K. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 07 Text: Jul2005 Type: published Y: 2005 Identifiers: – Type: issn-print Value: 00016772 Numbering: – Type: volume Value: 184 – Type: issue Value: 3 Titles: – TitleFull: Acta Physiologica Scandinavica Type: main |
| ResultId | 1 |
