Fascinating to know that swimmers (professional) employ breathing techniques, as well as being selective on which body part they choose to use during swimming e

Fascinating to know that swimmers (professional) employ breathing techniques, as well as being selective on which body part they choose to use during swimming events - given the ratio of how much oxygen is utilized when using a part of the body against not using it. Does the size of the diaphragm also takes into factor on this scenario? I guess it might be because that would be the muscle that helps compresses the lungs to be able to take in the most amount of air possible.