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Skeletal muscle 1 H MRSI before and after prolonged exercise. I. muscle specific depletion of intramyocellular lipids
Author(s) -
Vermathen Peter,
Saillen Pierre,
Boss Andreas,
Zehnder Monica,
Boesch Chris
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24168
Subject(s) - medicine , chemistry , endocrinology , creatine , treadmill , skeletal muscle , leg muscle , muscle fibre , physical medicine and rehabilitation
Aim of the study was to determine distribution and depletion patterns of intramyocellular lipids (IMCL) in leg muscles before and after two types of standardized endurance exercise. 1 H‐magnetic resonance spectroscopic imaging was performed (1) in the thigh of eight‐trained cyclists after exercising on an ergometer for 3 h at 52 ± 8% of maximal speed and (2) in the lower leg of eight‐trained runners after exercising on a treadmill for 3 h at 49 ± 3% of maximal workload. Pre‐exercise IMCL contents were reduced postexercise in 11 out of 13 investigated upper and lower leg muscles ( P < 0.015 for all). A strong linear correlation with a slope of ∼0.5 between pre‐exercise IMCL content and IMCL depletion was found. IMCL depletion differed strongly between muscles. Absolute and also relative IMCL reduction was significantly higher in muscles with predominantly slow fibers compared to those with fast fibers. Creatine levels and fiber orientation were stable and unchanged after exercise, while trimethyl‐ammonium groups increased. This is presented in the accompanying paper. In conclusion, a systematic comparison of metabolic changes in cross sections of the upper and lower leg was performed. The results imply that pre‐exercise IMCL levels determine the degree of IMCL depletion after exercise. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.