I see many people who over train. For example, there is a professional trainer at my gym who teaches & participates in multiple daily classes, runs up to 10 miles a day, and lifts weights every day. Her physique hasn’t changed in years and she is actually over weight. Unable to approach her, as she’s a friend of mine, I can’t believe she doesn’t see that her over training contributes to her repeated stress fractures and inability to make gains.
The greatest culprits are the fitness instructors who often also set the example of training despite injuries.
Talking to people who are over-training is difficult because their behavior is often not recognized as a problem, and they are positively reinforced in their behavior by the praise of others. I have heard the term ‘exercise bulimia’ as an extreme form of it.