CHARACTERISTICS OF INTRAMYOCELLULAR LIPID CONTENT IN SKELETAL MUSCLES OF OVERWEIGHT MEN AND ENDURANCE-TRAINED ATHLETES

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This study used proton magnetic resonance spectroscopy (¹H-MRS) to investigate differences in muscle group specific intramyocellular lipid (IMCL) storage characteristics associated with elevated muscle lipid storage, and to determine whether IMCL content is associated with maximal aerobic capacity. Seven healthy men [untrained (UT)], four overweight (OW) and six endurance-trained (T) subjects volunteered for this study. Data were acquired, using ¹H-MRS, from the tibialis anterior (TA), medial gastrocnemius (MG) and soleus (SOL) muscles. The IMCL content in TA was approximately twice as high in T subjects than in UT and OW subjects. In MG, IMCL was higher in OW and T subjects compared with UT subjects. A linear relationship existed between the VO₂max and IMCL in TA and a curve of second-degree relationship between the VO₂max and IMCL in MG. These results suggest that elevated IMCL deposits in TA might reflect enhancement of aerobic capacity, whereas the IMCL accretion in MG might reflect not only aerobic capacity but also overweight and obese conditions in men.