It doesn't have to be rough to leave you sore. More likely it IS just due to the unusual motions involved in sex, which most people don't perform until they have sex. Maybe try some exercise that involves the kinds of poses and motions used in sex, to help get your muscles more used to the motions and so they don't strain as much. I've heard yoga helps (makes sense, weird positions and stretching muscles you don't use a lot). In addition, drink more water. Sore joints in general can be due to dehydration, and you do lose fluids during sex, which can dehydrate you. Try drinking more water before or after sex, or just in general.
I have to agree about it being "rough" OR just strenuous. There's been times when I couldn't walk, couldn't sit down right, I've had bruises on my knees from being in a tight spot (a car lol) and also (I'm so sorry for the TMI) but also times where my "opening" is there was burning and soreness also. Mine has all been from rough and/or vigorous sex. That's just my personal opinion. :) Hope this helps!
sexual encounters could be considered strenuous activity. soreness could be due to how physically fit you are. kinda like when you go to the gym and work out. if you over do it at the gym and push your work out routine...it's bound to cause a little sore muscle here and there.
Might be to invasive of a question, but is it ROUGH sex?That definitely causes soreness.
Trying different may help. Slight soreness in certain ports of the body is expected.Your issues appear to be abnormal. If changing postures does not hep, consult a sexologist. Yourself on top position may help you to reduce soreness.....