system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what does caffeine actually do your muscles, especially regarding exercising?
gpt
Research by the American College of Sports Medicine has shown that ingesting 3-9 mg per kilogram of body weight (2-6 cups of regular coffee) approximately 1 hour before exercise can increase endurance or help with short intense exercise (around 5 minutes) where the person is working at near maximum.

The belief is that it has an effect on muscle contraction during anaerobic exercise – remember though this was tried on well-trained athletes in a laboratory environment.

Studies on elite distance runners and swimmers did show an increase in their performance times after they had ingested caffeine. The Australian Institute of Sport team found that caffeine triggers the muscles to start using fat as an energy source rather than carbohydrate sugars.

Certainly the enhanced performance using caffeine has been well documented and the Olympic Committee banned athletes from having more that 12 mg/ml in their urine samples. This equates to approximately 4 – 7 cups of coffee consumed within 30 minutes.