Overtraining is when a dog is physically overworked. Overstimulation is when your dog has been exposed to too many exciting or stressful events with no relaxation. With overtraining your dog may become lethargic, stiff, lame, fatigue, exercise intolerant even without much exercise. Other signs could be vomiting and diarrhea. With overstimulation your dog may become (more) anxious, irritable, compulsive, hyperactive and or destructive. The symptoms listed for overtraining or overstimulation is not exhaustive. Due to these symptoms your dog may opt to not participate in physical activities with you including walks. It is important to monitor for physical signs of burnout such as changes in gait or posture. If you are unsure if your dog is displaying any of these symptoms it is recommended that your dog is seen by a reputable veterinarian, or even a sport veterinarian, where they may suggest imaging such as radiographs. If that is the case it may be a good idea to have the radiographs be sent for review by a board-certified radiologist as well. Dogs that are overtrained or overstimulated may also have changes in their eating or sleeping habits. They may start to withdrawal from socializing with other animals or even the humans in the household or they may become clingier. You may see increases in fear or aggression towards housemates or humans. If this happens assess and address your training/rest schedule and incorporate mental stimulation such as a snuffle mat, lick mat, KONG original (or similar), KONG wobbler (or similar) or puzzle of some kind. Keep the puzzles easy and fun for the dog especially at the beginning. **Note that the suggestions are not physical, but they are mental/self-soothing in a healthy, productive and nondestructive way** Overstimulation, constant elation and or stress, can lead to a weakened immune system as well which in turn can cause your dog to be more prone to sickness and disease. If your dog starts showing signs it may be in their best interest to have your dog examined by a reputable veterinarian to at least establish a baseline especially if your dog does not improve.