The brain may try to recruit other muscles or alter exercise form to make movements easier when they become difficult, and individuals must override this instinct to maintain proper form.

“Because we're, as I say, we're doing chest. Yeah. Trying to isolate the pecs. There's some delts involved and triceps and work that or we're working legs, we're working back. The body normally doesn't work like that. It works as a unit, right? If you throw something, you don't do that from your tricep, right? It'll be from your foot through the hips, through the shoulder, whole body thing. So, when the exercise gets really hard, your brain is going to try to recruit or change the exercise to make it easier. So, I got to get people to override that instinct. Just stick with the form”