Training Stress Score
Above is a screen shot of a graph in Golden Cheetah representing my fitness over time. It starts when I started my last macro-cycle of training (12-9) and ends yesterday (6-21).
If you are not familiar with training using a power meter you may not be familiar with the concepts surrounding TSS. TSS is a way of quantifying how hard any given ride is relative to your fitness. Now that we have a way of quantifying the difficulty of workouts you can keep track of how much fatigue you are accumulating. The blue line in the graph shows the short term training load which is based on your workouts over the last 7-10 days. The green line is the long term training load which is based on your workouts over the last 6 weeks and is a good representation of how much fitness you have. The black line is the long term minus the short term which represents how fatigued you are (the lower the number the more tired you are likely to be).
As you can see since I’ve taken the last 6 weeks pretty easy my fitness has come down quite far while my fatigue rating has come up quite high. This would explain why I feel so energized when I get on the bike, but tire much quicker than I did back in April when I raced the Tour of the Gila. Now I just need to work to get my fitness back to and above where it was this spring.