In 34 my years in the fitness industry, I have worked at lots of health clubs and have seen a lot of things. Some things are amazing, some bizarre, and some just stick in my mind as a teachable moment for me. This is one of those memories.
The trainer said to her “Just one more" six times. By the third extra rep the client’s form was shot, and she was almost standing up in the machine. By the fourth rep she was clearly panicked. By the fifth rep she looked over at me as if to say WFT! I just shrugged my shoulders.
The trainer had no idea what the client was capable of or how fatigued she was on that particular set. If he did know he would not have had to say “Just one more” six times.
He wasn't aware. A trainers should do more that set the weights, count the reps, and say “Just one more’ redundantly until the client can't move anymore.