Originally Posted by
ericthered
I first realized improvement not on how I felt at the end of a ride (or hard hill) but on how quickly I recovered.
+1
DOMS (Delayed Onset Muscle Soreness) occurs the day after a ride (and can last even longer.) It indicates you've exercised enough to stimulate muscle growth, but it also signals your need to take it easy until the soreness gets less. Take it easy until DOMS disappears, which means you've recovered enough to stress the muscles again.