Bmanners wrote:

HTFU your competition is

This kind of suggestion leads to injury.
Why are you sore? Is it because you're stiff/tight? Try using a foam roller to loosen yourself up.
How long have you been sore? Has it been a couple days? Couple weeks? A month? If it's been more than a week or two, and you haven't been doing anything abnormally hard (like racing every weekend or something) you may be over training.
Are you doing enough core easy workouts/aerobic training/recovery workouts? Or are you just hammering at the same level every day? How much speed/intensity have you been doing?
How many years have you been at it? How many miles do you have on your legs? What are your goals? All this makes a difference in whether you rest or push through.
If you are truly sore, i.e. there is muscle damage, you will make very little gains before you recover- let your muscles heal. You can't just keep breaking yourself down without letting yourself build back up, you will end up over trained, injured and/or sick.
But, you also can't always help it and sometimes you have to go out and get the training in when you're a little sore; but the accepted rule is that if you're really sore it's time to just do some recovery workouts or easy(ier) endurance workouts (that can be long, but must be easy).
Why not hit the pool more for a couple days; it gives the legs a rest and has been shown to help them recover more than rest alone.