Say a person can do a 400m run in 1:00, but is unable to do a 1600m in 4:00. What is most likely the main limiting factor in this? What is holding back being able to keep going at this pace for longer? The respiratory system? The lungs? I am assuming that the legs, etc. are strong enough to perform this. I am more interested in what the relative importance of things like the heart and lungs are in this task.
Maybe another way to look at it is for a person who is fairly physically fit through years of exercise, how important are the heart and lungs and other systems in anaerobic exercise?
To me, it seems like the lungs and the ability to get oxygen to the muscles are more important than the heart being able to increase to a high beats per minute, but I am not sure.