That's an awesome shot with the waterflow.
What I've learned about sports and cameras ..
- you really need to know how fast your camera is from press of the release to the image being taken. This allows you to better time motion image captures rather than just pray & continuous shoot all the time.
- and if you can make sure your focus is continually refocusing even while not taking a shot. So that when the opportunity arises you can take the shots. With swimming it's a repeated process up and down a lane so it's easier to get in the groove of shooting.