Running

nor do i to be completely honest, but it assigns a Training Stress Score for each activity I do and upload, based on power for cycling, threshold pace for swimming and heart rate/pace for running, it basically measures how heard you push yourself in each workout. this immediately effects your short term training load (pink line) and in time affects your longer term training load (the blue line) the yellow line is the balance between those two and so represents freshness. the best performances (peaks) theoretically occur when the blue line is really high and the yellow line is slightly higher. my race is at the at the point on the dotted line where the pink and yellow lines spike.

TL:DR - I should be in top form for a race on Sunday so have no excuse not to do well - science sayz so.