Abstract
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Medicine and Science in Sports and Exercise |
| Vol/bind | 37 |
| Udgave nummer | 6 |
| Sider (fra-til) | 937-43 |
| Antal sider | 6 |
| ISSN | 0195-9131 |
| Status | Udgivet - 2005 |
Bibliografisk note
Keywords: Adenosine Triphosphate; Adolescent; Adult; Energy Metabolism; Female; Humans; Leg; Magnetic Resonance Spectroscopy; Male; Muscle Contraction; Muscle, Skeletal; Phosphocreatine; Reproducibility of Results; TorqueCitationsformater
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I: Medicine and Science in Sports and Exercise, Bind 37, Nr. 6, 2005, s. 937-43.
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - ATP economy of force maintenance in human tibialis anterior muscle.
AU - Nakagawa, Yoshinao
AU - Ratkevicius, Aivaras
AU - Mizuno, Masao
AU - Quistorff, Bjørn
N1 - Keywords: Adenosine Triphosphate; Adolescent; Adult; Energy Metabolism; Female; Humans; Leg; Magnetic Resonance Spectroscopy; Male; Muscle Contraction; Muscle, Skeletal; Phosphocreatine; Reproducibility of Results; Torque
PY - 2005
Y1 - 2005
N2 - PURPOSE: The aim of this study was investigate ATP economy of force maintenance in the human tibialis anterior muscle during 60 s of anaerobic voluntary contraction at 50% of maximum voluntary contraction (MVC). METHODS: ATP turnover rate was evaluated using P magnetic resonance spectroscopy (P-MRS). The total volume of ankle dorsiflexor muscles was assessed by H magnetic resonance imaging (MRI) (H-MRI), and the fiber type composition of the tibialis anterior muscle was evaluated using histochemical analysis of muscle biopsies. RESULTS: The tibialis anterior muscle occupied 59.7 +/- 0.6% (mean +/- SEM) of the total ankle dorsiflexor muscle volume, which was 267 +/- 10 cm. Relative cross-sectional areas occupied by Type I, IIA, and IIB fibers in the tibialis anterior were 69.3 +/- 2.2, 27.4 +/- 2.76, and 3.2 +/- 1.0%, respectively. ATP economy of force maintenance did not change significantly during the 60-s contraction. It averaged at 4.81 +/- 0.42 N.s.micromol-1, and correlated with the relative cross-sectional area of the muscle occupied by Type I fiber (r = 0.73, P < 0.01). For the second half of the contraction, subjects dropping in force showed lower ATP economy compared with those maintaining the force (3.7 +/- 0.6 vs 5.3 +/- 0.6 N.s.micromol-1; P < 0.05). CONCLUSION: It is argued that the unchanged ATP economy of force maintenance during the voluntary contraction could be due to an increase in the ATP economy of contracting muscle fibers offsetting the effects of increased temperature and low ATP economy of Type II fibers. Mechanical interaction between motor units could also act to improve ATP economy of force maintenance.
AB - PURPOSE: The aim of this study was investigate ATP economy of force maintenance in the human tibialis anterior muscle during 60 s of anaerobic voluntary contraction at 50% of maximum voluntary contraction (MVC). METHODS: ATP turnover rate was evaluated using P magnetic resonance spectroscopy (P-MRS). The total volume of ankle dorsiflexor muscles was assessed by H magnetic resonance imaging (MRI) (H-MRI), and the fiber type composition of the tibialis anterior muscle was evaluated using histochemical analysis of muscle biopsies. RESULTS: The tibialis anterior muscle occupied 59.7 +/- 0.6% (mean +/- SEM) of the total ankle dorsiflexor muscle volume, which was 267 +/- 10 cm. Relative cross-sectional areas occupied by Type I, IIA, and IIB fibers in the tibialis anterior were 69.3 +/- 2.2, 27.4 +/- 2.76, and 3.2 +/- 1.0%, respectively. ATP economy of force maintenance did not change significantly during the 60-s contraction. It averaged at 4.81 +/- 0.42 N.s.micromol-1, and correlated with the relative cross-sectional area of the muscle occupied by Type I fiber (r = 0.73, P < 0.01). For the second half of the contraction, subjects dropping in force showed lower ATP economy compared with those maintaining the force (3.7 +/- 0.6 vs 5.3 +/- 0.6 N.s.micromol-1; P < 0.05). CONCLUSION: It is argued that the unchanged ATP economy of force maintenance during the voluntary contraction could be due to an increase in the ATP economy of contracting muscle fibers offsetting the effects of increased temperature and low ATP economy of Type II fibers. Mechanical interaction between motor units could also act to improve ATP economy of force maintenance.
M3 - Journal article
C2 - 15947717
SN - 0195-9131
VL - 37
SP - 937
EP - 943
JO - Medicine and Science in Sports and Exercise
JF - Medicine and Science in Sports and Exercise
IS - 6
ER -