The answer should be simple. If the client is pushing themselves TOO hard during sessions, then they are pushing themselves outside the perameters of benefit of the session. You tell them that they are to obey your instruction, as it is being given in order to provide them with the most effective route to accomplishing their goals. Define your role in the relationship as TRAINER and not babysitter. Now, doing this with tact and grace however, is another topic all together.
I affirm the effort, but prioritize safety.
I have a fantastic student who pushes 100% all the time. Being a martial arts instructor, there is inherently more risk in some of the exercises we do, and there have been a few instances where I have had to say, “Your done. It is not safe for you to continue.”
She is always disappointed initially, but later appreciates me more for caring, and looking out for her safety. A gentle, honest word can go a long way to change attitudes.
Your redirection to overarching goals will help them from focusing on overdoing a particular exercise.
It depends on how the person is pushing themselves. I work people through phases in order to prepare them for a different intensisty level at each phase. If they exceed the range i give them for rep counts then weight is added. Everyone is informed on the risks of adding weight and forced reps and working to extreme fatigue. If a client cant get enough or adhere then i give them what they want to a degree. IF they want fatigue then i take it out of their lungs with intervals between sets. Pushing the lactic threshold in that manner will slow anyone down.
All depends on the situation.
I had a client like this. I would ask for 15 of something and she wanted to do 25. The best way I found to train her was to move her quickly from exercise to exercise. I mixed it up with machines, body weight, and small tools (physio balls, med balls, free wts). I designed a program that was 1 set of 15 with multiple exercises. If we had MORE time I would have run through the program a second time. I found when I built in 3 min cardio bursts in between every few exercises, she was more about “what’s next” instead of I want more! It was a lot of fun although it took a ton of planning. I think over time we both really enjoyed it and she got great results. Every week I would intro a new exercise to replace the way or equipment she had used the previous session so it was fresh and exciting.
And more to the point, are they not progressing or are they getting injuries? If they are showing signs of over training, then you need to step in. I don’t know exactly what is happening so it is hard for me to advise more. But I adjust my clients programs with the guidance of their recovery markers. I ask questions like, “how are you sleeping?”, “how is your energy during the day?”, etc. And I keep a close eye on their stats, heart rate, repiratory rate, performance factors, etc.