system
Given the following post, respond as if you're commenting on Reddit:
human
How does body shape relate to swimming 
performance ?

Here is a question from my swimming class. We have noted that girls are usually faster with kick exercises, whereas boys are faster with arm practice.

Boys think it has to do with the distribution of body fat (or possibly body shape), and girls think we are just lazy (and that we shouldn't be so rude!).

Has there been studies on the differences between male/female swimming?
Is there a numerical way to compare men's and women's records?
Is swimming more, or less "gender imbalanced" than other spots such as athletics?
gpt
Disclaimer: the mechanics of a human body -- with all of its density variations, oddly shaped limbs with multiple joints, varying cross sectional area, etc -- moving through a fluid like water can get pretty complicated if you try to break it down and analyze how men and women might be better at one type of stroke or movement compared to another. That being said, the difference in "arm practice" performance may be as simple as men generally having superior upper body strength to women.