Speaking of sprinting, this study just came across my screen:
https://kar.kent.ac.uk/78570/1/Winfi...0al%202019.pdf
The main finding of this study was that including repeated 30-s maximal sprints during 4 h low321 intensity cycling did not affect the reduction in GE from the start to the end of the session, compared to a work-matched constant load cycling in elite cyclists.
During group rides, I was accustomed to doing several hill sprints, mostly because I was good at them and that's fun. I always wondered how much that affected my ride - it didn't seem to be a negative.
Edit: I always wondered why I could out hill-sprint everyone in the group even though I was older than any of them. My guess was because I was the only rider in the group who strength trained. Back then it was poo-pooed for cycling. "Everyone knew" that gym work made you slower if it did anything. The other possibility was that I trained to pull up on the backstroke. Though I only unweighted and didn't pull up when pedaling normally, I trained the backstroke on my rollers. The backstroke makes a much smaller difference on a flat sprint as it's only effective during the initial acceleration, though I won most of the flat sprints, too.