My short answer is yes, fins help. But there needs to be a lengthy discussion as to why.
Let’s begin by talking about the importance of kicking. In swimming, kicking only generates at most 10% of your forward movement, which doesn’t seem like much. However, inefficient kicking can attribute to dragging your body in the water, which can slow your speed. Also, kicking uses up oxygen. So for both reasons, you need to develop a strong and efficient kick. One of the best ways to do this is to use fins.
My experience with fins started at an early age when I was a competitive swimmer throughout my childhood. I was exposed to fins, but would only use them while tapering, using them for 50 or 100 meter repeats with roughly two to three minutes of recovery.
It wasn’t until 2005 when I joined the Navy as a rescue swimmer that I learned the true value of using fins. Fins are great for helping develop speed and strength in your kicking, which in turn will help with your overall act of swimming. A strong kick will not only get you moving in the water, but also helps develop your hip flexors which can in turn help your running and cycling.
Determining the amount of distance you need to do in your fins, the speed of the workout, and what days to swim with fins, depends on the goal of your workout and where you are in your season.
Personally, I use the bigger TYR Crossblade Fins in my workouts. I’ll use them during warm ups for maybe 200 to 300 meters, and during a drill set or main set where it makes sense.
If you want an even better workout I suggest adding in paddles such as the FINIS Freestyler Paddles (my favorite) or TYR Catalyst Paddles and using the TYR Crossblade Fin. Together you are working on good form up front while building your strength in your legs.
Some examples of good workouts that I give my athletes can be found here at the training peaks exercise libraries I offer to those athletes looking for ideas.
Thanks for a great question Mark!