P-90 works to a certain extent...but only really as a cardio exercise. However, If you ask me from a person who lifts 4 days a week, I would say the most benefit for me comes from core/circuit workouts..It's not all about the bulk. If you really want to be able to paddle do exercises which incorporate your whole body (mt biking, running, swimming, yoga, basketball) anything where you need endurance will greatly inmprove your ability to stay out in the water...just my .02