Saw some guy at the gym doing dumbbell overhead press with one foot extended out and balancing on the other leg. I've seen other people do similar exercises where they (i guess) are trying to engage their core stabilizers while performing the reps. I think p90x2 has a lot of this type of workouts.
Is there any benefit to this?
Idk but am I wrong to think its better to have a stable base, perform the exercise, and then if you want to work out your core do that separately?
Anybody have any input or opinions on this?