Today’s workout is pretty simple. A kick set, a set with a little butterfly and or breastroke work, and then a longer main set with a good chunk of fins use in it. Fins are the biggest advantage you can give yourself in the water. I think the world record for the 50m freestyle with a monofin is in the 15 second range. Without fins it’s 20 something. Going 25% faster than the world record as an astronomical difference and the only thing that created that difference was a giant monofin and rules that allow the swimmer to stay underwater.
So when you put fins on for the last part of the main set let your legs do some work and see how streamline you can keep the rest of your body. You’ll still be swimming freestyle, but the workload will be shifted substantially. As long as your legs don’t give out and your ankles feel OK you could be swimming 5-10 seconds faster than your normal threshold pace at threshold intensity. Swimming faster than threshold intensity teaches you how to swim faster than threshold intensity.