Paddle vs. Propeller: Which Swimming Stroke is Superior?

Two swimming strokes—one that pulls through the water like a boat paddle and another that whirls to the side like a propeller—are commonly used by athletes training for the Olympic Games. But elite swimmers and their coaches have long argued over which arm motion is more likely to propel an aquatic star toward a gold medal.

Rajat Mittal, A Johns Hopkins fluid dynamics expert, has found that the deep catch stroke, resembling a paddle, has the edge over sculling, the bent-arm, propeller-inspired motion.