I came across the article, [The Art of Connected Swimming: Jonty Skinner and Kristian Gkolomeev](https://www.swimmingworldmagazine.com/news/the-art-of-connected-swimming...), today and it has some interesting things to say about the core and how our brains are wired. Skinner talks about the need to develop the core. As he says, "The solution is to rewire the brain to focus on the core. Connection is about the core and driving everything through the body and not through the hands."
I wrote a more extensive post on this in 2014 entitled Reason Not to Use a Pull Buoy. The post explains the paramount importance of the core in swimming: the transfer of power, base of support, and the kinetic link, to mention a few. I recommend the post to anyone who wants to better understand why core is important and the role it plays in creating efficiency and speed.