I'm less familiar with Enterprise and Voyager, but in TOS, TNG, and DS9 I have repeatedly seen Star Fleet officers engaged in melee combat perform this awkward and slow-looking attack where they clasp both hands together and swing at their opponent. At times it looks like they are trying to chop wood with no axe, hitting the opponent from the side. Other times, it looks like they are playing volleyball extra vigorously, uppercutting their enemy with both hands.
If this were just in TOS, I would assume it was just the choreography of the day. However, it is still present in the more modern incarnations of the show. Is this part of a fictional martial art that is used by Star Fleet (and possibly others? I can't recall if, for example, I have ever seen klingons use this technique), or is it part of a real martial art? If there is no canon explanation (i.e. this move is not part of either a real or a fictional martial art), then why did they continue to use such awkward choreography in the more modern series?