I'm glad this forum is already rolling because I just had my first deep tissue massage on Tuesday, and felt I needed to throw out my experience.
I've been playing water polo for about 10 years, and have chronic stiffness and knots all over my back and neck, and even my hamstrings. The therapist was great, and she managed to find every last spot that needed work, and really get deep into them. I did have two, apparently, unfounded concerns:
1) How therapeutic would a deep tissue massage be at spa that seems to cater more towards beauty supplies and mother's day excursions? (hey, i had a gift certificate)
2) How good would a deep tissue massage be by a woman? (And actually, this was my lesser concern - I've known many strong women, and certainly technique counts for a lot here as well)
I lucked out (sorta) in both respects, but if you don't want to go in blind, ask around for references (this girl was Nicia at G2O on Newbury St in Boston). If any therapist is certified in a certain kind of massage, then you should be good to go anyway.
The only reason I say "sorta lucked out" above, is that about an hour later my throat started to feel swollen, my ears were getting congested and I just generally felt like I was catching a cold. I got out of water polo practice early, and skipped rugby that night to go home and rest. Sure enough, the next day, I was laid up in bed all day with a fever. Throat was so swollen it hurt to eat (not that I had much of an appetite anyway), and I was too addle-minded to do much more than lay down. I took a lot of Zicam, got as much water as I could stomach, and started to feel somewhat less crappy by Thursday. Now it's Friday - I feel functional again, but still have some residual symptoms (throat is still sore, and apparently a runny nose now? but that may also be because it's allergy season here).
I had heard in passing that deep tissue releases toxins and can "make you feel bad" afterwards, but it hit me like a wrecking ball. Maybe my case was an extreme example, but my advice - drink lots of water before, and immediately after, make sure you're taking your vitamins, and just do whatever you would normally do to prevent getting sick before and after you get your massage.
Anyone else have different experiences? This was also my first deep tissue massage, so there may have just been a lot of junk built up over the years.