The second edition of “Essentials of Strength Training and Conditioning define overtraining as “excessive frequency, volume, or intensity of training, resulting in fatigue (which is also due to a lack of proper rest and recovery. Overtraining is simply the stimulus. Overtraining syndrome is the condition resulting from overtraining. It is also referred to as staleness. This syndrome can, but does not always, include plateau or decrease in performance. Many alternative terms have been suggested for overtraining, including burnout, chronic overwork, physical overstrain, and overfatigue. Some authors use the term overtaining only when a decline in performance occurs.
My purpose in leaving the definition is because many fitness professionals can’t see when they are overtraining as well as as fitness enthusiasts.
If one know the definition, it then become easier to pinpoint what someone who is overtrained is exhibiting.