Strength comes in varieties, too. And muscles take exercise in order to produce maximal strength - special exercise for special types of strength. So a Vulcan of either gender might be born with the potential to be three times stronger than a human, but Archer might be closer to his 100% than T'Pol is to hers, explaining why T'Pol does poorly in wrestling (say, against Klingons) while Archer fares relatively well (again against Klingons).
As for Kasidy, she might have been talking about males even though she didn't specify this. After all, she was commenting on the specific incident of Solok vs. Ben Sisko. So T'Pol's poorish showing might be explained by sexual dimorphism, too.