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In vivo mitochondrial function varies with muscle and training status in young adults
Author(s) -
Larsen Ryan Godsk,
Callahan Damien M.,
Lanza Ian R.,
KentBraun Jane A.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.958.13
Subject(s) - phosphocreatine , isometric exercise , skeletal muscle , in vivo , oxidative phosphorylation , vastus lateralis muscle , medicine , endocrinology , contraction (grammar) , chemistry , biology , energy metabolism , biochemistry , genetics
Phosphorus magnetic resonance spectroscopy (MRS) was used to measure the effect of training status on skeletal muscle oxidative capacity ( V max ), an in vivo marker of mitochondrial function, in two morphologically‐distinct human muscles‐tibialis anterior (TA) and vastus lateralis (VL). Methods: Healthy, untrained (7F, 7M, 26±1 yrs, mean±SE) and trained (7M, 1F, 28±1) adults performed a 16‐s and a 24‐s maximal voluntary isometric contraction of the TA and VL, respectively, while intracellular phosphocreatine (PCr) concentration was measured by MRS. The rate constant of post‐contraction PCr recovery ( k PCr ) was determined and used to calculate V max ( k PCr · resting [PCr]). Results: There were main effects of muscle and group on V max and k PCr such that oxidative capacity was higher in VL than TA (p≤0.046), and higher in trained than untrained (p<0.0001). Conclusion: This study provides novel evidence of muscle‐specific differences in in vivo mitochondrial function that is independent of training status.