I'm an armchair tennis player. I've not played since school, but love watching it so I could be wrong about the physical capabilities.
However, I do wonder why female players are expected to only play best of 3 sets while men play best of 5?
I think it should be equal pay for equal play. It doesn't matter if the contest is finished in an hour or seven hours. It could still be equal sets to play.
Is the difference just an out-dated rule or is there a physical reason behind it?