tight muscles and the Bike

Try working these into your regular routine:

Active stretching
Massage - The Stick, foam roller, etc.
Static stretching

Wear Newtons.

You'll be fine for the 50K this weekend.

Science rules. 

Yes. Someone clued me into a research article about how The Stick is good for warming up as well. So, I've gotten in the habit of using it (albeit lightly and not for very long) before my rides and runs, and I do feel it helps to use it before workouts. I still do my active stretching routine as well.

And to everyone else, be nice .

Darn! 

I'm not very good about stretching, but I've been sore and tight lately so I'm doing that more often.  Stretching every day (whether I'm training or not) has helped with that a lot. 

So, I would recommend that you keep stretching if your muscles are tight.  A massage isn't going to do much good if you're not also stretching on your own.

I get a massage about 3-4 days before a race.  It's more of a stretching massage vice deep tissue.  Make sure you get someone that knows what they are doing.  But it's not going to do you any good unless you are stretching on your own as well.

Also, you have to ask what muscles tighten up.  On the bike, in Aero, your traps will tend to tighen up more.  While running, your muscles shouldn't tighten up rather than fatigue.  It's after the exercise that they generally tighten up.

You have a 50K run or a 50K bike this weekend?