I've seen two ways of generating power during striking. The first way is to sink at the moment of striking. Others, like in Sun tai ji, recommend rising when striking. Which method do you guys use and why the totally opposite methods?

It depends if you're striking upward or downward.

^

Different strikes require different mechanics..

Exactly what strike are we talking about, and in what situation?

There are too many variables in a fight to say, *sink* or *raise* at the moment of striking, thats not gonna help you at all...

I put the same question in the Taijiquan discussion board. Your answer Tim seems logical.
Because both ways are possible. Usualy combat systems use one or another, sometimes probably both of them.