Cat leaps and "scissor leaps" (or switch-leaps) are typically done with very different arm movements.
Usually, during a cat leap, the arms move from low position to forward middle, and then to crown as the first leg rises.
On a switch-leap, the arms swing forward middle as the first leg swings, and then forcefully side middle during the switch. Some kids seem to benefit from swinging the arms backward during the step leading into the switch leap, but I personally don't see a big difference, and it looks to me like it slows down whatever speed they build in their chasse.