Hey now. Swimming may not be a sport that involves a ball of some kind being put into a net, hoop, or hole, but if you knew any competitive swimmers you'd see that they train pretty fucking hard; to the point where it rivals unhealthiness.
My brother swam for Auburn University when they were going through their big streak of National Championships, and there was a day of training called "Big Dog Day", where over 100 workout machines were placed in a gym with the lights turned off, the heat turned on, and a strobe light in the center. You rotated from machine to machine for a minute and a half to two minutes each over the duration of the entire workout. The weight lifting coach placed an old can of tuna right in front of a machine called the "Hand Bike" which involves the entire body, and the large trash can filled with trash and puke. Essentially you'd do the Hand Bike as long as you could before you broke down and vomited. By the time my brother and his teammates left the gym, sweat was squirting out of their sneakers.