It has to do with fast twitch/slow twitch muscles. Men can lift a lot of weight a few times. We can lift less weight a bunch of times.

I agree with the previous post who recommended weight training. During peak riding season, you probably don't want to train legs heavily, but you can certainly train abs & upper body.

On the off-season, I concentrate on cycling related lifts, e.g., squats, seated hamstring curls, lunges. Can't forget the triceps & delts - those hold us in the tuck position for miles & miles (I'm a roadie).