Originally Posted by
FBinNY
I think this is the answer. If you're riding full out, trying to improve, you'll be tired. I'd break it up with an easy day where you ride at a comfortable pace, maybe for a longer distance on flatter terrain.
In any case, that rubber legs feeling is a characteristic effect of lactic acid accumulation in the muscles. It may indicate that your legs are getting stronger, but the rest of you, specifically your heart and lungs are lagging a bit. But that's only one possibility. Try to mix up your training with fast days, long day and hard days, and don't forget to include some easy days.
I hear you. But I figured that having rest days and rarely riding back to back days would give my legs time to recover. I used to do a lot of weight lifting/power lifting and that theory of a full day off in between work out days would be enough recovery. But also with my lifting programs I was never doing squats in back to back work outs for example so even lifting every other day I would do squats once in 5 days so I guess that is also a big difference. But yeah it is lactic acid build up. I guess tomorrow I will try a leisurely paced ride on flatter ground and see how it goes.