The Importance of Strength Training

We tend to either swim forwards or backwards, so we're lacking exposure to multiple degrees of freedom in space. We also don't have a way to build non-isometric strength because we don't have an incrementally loadable external object. So my advice would be to have a look at things this way: What degrees of freedom are involved? Does it permit the development of strength via external loading? And does it have elements of compression and tension?" Find something that you enjoy participating in, and that hits as many of those metrics as possible, and you'll be good to go.