Strength training in swimming is critically important. It is a sport of paradoxical strength, whereby a swimmer can become physically bigger and stronger, yet swim slower. That is due to the extraordinary sensitivity of drag to the shape or morphology of the swimmer. Cross Fit tends to build massive strength, but that does not always translate into faster swimming.
We don’t like doing heavy lifts in swimming. We prefer using body weight, more repetitions and ballistic movements for coordination and speed.