The Training Readiness Score provides information on your level of recovery which you can factor into your decision as to whether to train as normal, have an easier training day or take a rest day.
The score is calculated based on your answers provided via the Training Readiness Assessment and current / long term training load information retrieved from Strava (where you have linked your Training Trends account to Strava).
The highest possible score is 100. A score of 75 or below suggests that you should consider only doing easy training and score of 50 or below suggests you should have a rest day. If your score is consistently below 75 (and you are not sick or injured) then you should consider how your lifestly outside of training may be impacting your training performance. Following good training habits will lead to better scores.