Great question. I do not recommend even wearing a HR monitor for these ME workouts. HR is not a good indicator of the training load. You no doubt discovered this when you got very sore for a few days.
To prevent the extreme DOMS that can occur for many people I recommend doing the first couple of these WE workouts at about 75-80% intensity. Don’t jump too high. Don’t goo too deep. It is at the ends of the range of motion that the muscle damage happens and this ME lite will help you ease into it and give you time to adapt without crippling yourself.
I hope this helps.