TRIGLYCERIDES ARE THE FUEL FOR TRAINED LARGE-MUSCLE ACTIVITIES
Martin, W. H. (1997). Effect of endurance training on fatty acid metabolism during whole body exercise. Medicine and Science in Sports and Exercise, 29, 635-639.
For trained individuals performing exercises involving large muscle mass (e.g., running, rowing, cycling) up to two hours in duration, plasma free fatty acids are a less important fuel source while intramuscular triglycerides supply the major portion of the increase in oxidized fatty acids.