I think I'm the crazy one. I ride 6 miles to the gym to do a spin class, then ride 2 miles to work, then ride home 6 miles. I found I wasn't challenging myself on the bike outdoors, and the spin classes help motivate me to up the resistance. On a typical commute, I average about 140 watts. Spin class I average 220 watts. I've seen a significant improvement in cycling ease, and my commute average since I started has gone up to 150 watts with the same RPE. I also do some strength classes twice a week, but so far nothing heavy weight training.