Thanks for the inputs. The flutter kick is what I use when covering distance, but evidently just need to exercise my quads to strengthen them. I was hoping it wasn’t just me! ; ) It’s when I have to swim against stronger currents for longer amounts of time, that I really have to strain with my downward kick. And I struggle even more with the downward kick when snorkeling with my dive fins. In land sports like football and baseball, I was one of the guys that could accelerate more quickly, so maybe my hamstrings are just a lot more powerful than my quads.