I play for fun but still, it seems to me that these players are generally not nearly in the peak condition they could be. Specifically in the areas of muscular and aerobic endurance,it's as if the conditioning deemed apt for women's tennis has lagged behind the developments in the game.
I disagree, many of the women on tour are very fit. It would be nearly impossible for a non fit person to complete 3 sets of pro level tennis if they didnt have the strength and endurance.
Not every woman is super lean and muscular though and that might lead people to think otherwise on ocasion.
This has nothing to do with their physiques. Yeah they have the strength and endurance to complete 3 sets ( sometimes barely ) but I'm basing my assessment at watching top 10 players do just that. Players were completing 3 sets back when when they hardly broke a sweat. The overall level of endurance-based fitness is - IMO - not nearly where it could be. I'd say that the average pro women's soccer player or middle-distance runner is in far better condition. I'dalso say that ATP players have a higher overall level of fitness.