The problem is that when most people put weight on their elbows it dramatically increases the tension in their neck and shoulders. I will wager that during the debate Hillary will be putting lots of weight on her elbows and that will become obvious toward the end of the debate.
My expectation is that toward the end she will have horrible neck pain and that may impact her performance during the debate. Watch for facial expression and neck tension.
I would bet it will cause some coughing problems for her.