Loosely speaking, a training program consists of 2 parts, training and recovery. What happens during one aspect has an impact of the other. More and/or higher intensity training will require more and/or better recovery. Obviously this is a very simplified statement and variations exist depending on training aims and training periodisation (functional overreaching periods spring to mind).
Most coaches will closely measure training volumes, volume loads, frequencies etc but it is also necessary to track recovery. It’s not always easy. What do you measure? Physiological markers are useful but not always practical or practicable and aren’t really usable in isolation. Recovery is a mix of physiological and psychological parameters the relationship between which isn’t fully understood and, as with training, will be specific to each individual. There are a massive amount of physiological, psychological and performance measures that can be taken, what you have to identify is which of those is useful to you as there is no point measuring for measuring’s sake.
As part of this monitoring I like to use short questionnaires to get some quantitative scores on an ongoing basis. The REST-Q is a fairly long questionnaire but is quite useful to use periodically around competitions or more focused training bouts to gain an in depth understanding of the athlete’s response to the preparation throughout that period. It has a smaller brother though too, the recovery-cue. It comprises 7 questions with multiple choice answers that can be used weekly to help ascertain the effect of the previous week’s training and recovery. This is one method that I find useful, particularly when the athlete is abroad in order to gain more insight into the impact of training and to ensure adequate recovery is being taken. Understanding the recovery response of the athlete to training is integral to ongoing program design and it is important to have a method that works for both the coach and athlete.