My Zwifting/Trainer efforts are typically in the winter and are dedicated to training my low cadence, out of the saddle muscles, which isn't always easy to do in the winter, since the big hills here are in the shadows of deep canyon walls, and are often wet/icy/sandy and are really sketchy to come DOWN, or require hard non-stop braking for 10's of minutes at a time, which can cramp the cold hands. Therefore it's the Zwift volcano climb for me.