Final answer:
Research confirming that caffeine intake within the 3-6 mg/kg range enhances athletic performance is true, particularly regarding endurance and strength. Caffeine's effects include improved aerobic and anaerobic performance, increased fat oxidation, and reduced perceived exertion.
Step-by-step explanation:
The statement that caffeine intake of 3-6 mg/kg can improve athletic performance in trained populations is True. Research supports that moderate doses of caffeine, approximately around 5 mg/kg, are beneficial for improving various aspects of physical performance. Caffeine is known to enhance aerobic performance, particularly in endurance sports, and improve anaerobic conditions. It aids in increasing the basal metabolic rate, fat oxidation during aerobic exercise, and muscular strength and power. Additionally, caffeine has been found to reduce perceived exertion, particularly before constant load exercise, thereby potentially enhancing workout capacity and efficiency.