Lats? What Lats?

You can vary your pull quite a bit to emphasize different muscle groups. For example, you can pull one way to get your lats to do most of the work. You can do this by keeping your pulling arm relatively stiff - that is to say don't flex much at the elbow. When you're pulling, imagine your arm being anchored in the water and using your lats to roll your body and pull you forward. At the other end of the spectrum, you can bend your elbows a lot and throw a lot of emphasis onto the triceps. In that case you'll get most of your forward motion from the latter half of the underwater stroke. It's basically a glorified triceps extension at that point, as you're really "pushing" yourself forward instead of "pulling" yourself forward. I find it useful to vary my pull like this during sets. Not all of the time, of course, but on some days focus on lats and on others focus on triceps. It's the same train of thought as doing pulling and kicking drills instead of just swimming 100% of the time.

You can vary your pull quite a bit to emphasize different muscle groups. For example, you can pull one way to get your lats to do most of the work. You can do this by keeping your pulling arm relatively stiff - that is to say don't flex much at the elbow. When you're pulling, imagine your arm being anchored in the water and using your lats to roll your body and pull you forward. At the other end of the spectrum, you can bend your elbows a lot and throw a lot of emphasis onto the triceps. In that case you'll get most of your forward motion from the latter half of the underwater stroke. It's basically a glorified triceps extension at that point, as you're really "pushing" yourself forward instead of "pulling" yourself forward. I find it useful to vary my pull like this during sets. Not all of the time, of course, but on some days focus on lats and on others focus on triceps. It's the same train of thought as doing pulling and kicking drills instead of just swimming 100% of the time.