It’s hard for me NOT to participate since my background is in Group Fitness. crossing over into Personal Training allows me to infuse group class energy with my participation. That said, my eyes are on the participant’s form, alignment, and energy the WHOLE TIME so I am not always going full out.
On tricky exercises (some TRX or plank based moves) I will demo, then individually correct form or just coach and motivate. I even participate sometimes with my private clients especially in some cardio exercise so I can pace them.