In Golden Cheetah if I go to Trends > Summary and look at the Athlete Bests I see 30 Sec peak power, 1 min peak power, etc. In each of those sections I see the position number, wattage, date and a number in parenthesis. What is that number telling me and why is it something negative and other times positive?
That’s telling you what your TSB (Training Stress Balance) was at the time you set the PR. This could be useful or not, depending on a bunch of factors (e.g., the type of training you’ve been doing, overall training volume, your individual genetics, etc…)
Random number example follows: Some people need/like to be +20 come race day in order to perform their best. While some will feel stale at +20 and prefer -10. Again, it is very individual.
Use it for trending against how you feel on those days (RPE) and how you actually perform to see what works best for you.
Edit addition: Found a relevant TR write-up for you: