Bob and I do workouts to tax our muscles.
In a pit, we do basic squats and push ups then a dot torture.
As the training goes on we add timers. Now we are physically taxed and have a stresser in getting off the shot.
I like changing the drill after 3 attempts. I get use to it and I start “hacking” the drill.
We don’t do a lot of seated positions. Mostly standing, walking running.
Adding timer or reloads make any drill stressful.