Intramuscular triacylglycerol utilization in human skeletal muscle during exercise: Is there a controversy?

Abstract

Intramuscular triacylglyerols (IMTGs) represent a potentially important energy source for contracting human skeletal muscle. Although the majority of evidence from isotope tracer and 1H-magnetic resonance spectroscopy (MRS) studies demonstrate IMTG utilization during exercise, controversy regarding the importance of IMTG as a metabolic substrate persists. The controversy stems from studies that measure IMTG in skeletal muscle biopsy samples and report no significant net IMTG degradation during prolonged moderate-intensity (55-70% maximal O2 consumption) exercise lasting 90-120 min. Although postexercise decrements in IMTG levels are often reported from direct muscle measurements, the marked ..