バキバキ sounds too painful to be innuendo but it's apparently also an impact noise. Unless she's talking about Grappler Baki, which would also be painful innuendo I think.

Ontariotaku said:

バキバキ sounds too painful to be innuendo but it's apparently also an impact noise. Unless she's talking about Grappler Baki, which would also be painful innuendo I think.

A quick look at google images should give you a good answer to what it actually means.

Very good. Fixed.