I think everyone should incorporate some form of strongman training into their workouts. The loaded caries will challenge the core musculature like no plank, crunch, or even squat ever could.
Here's my write up, including some exercise examples and the effects of strongman training on free testosterone.
Train Strongman Feel Great! | Jason Cholewa - Strength and Conditioning Lecturer at University of Kentucky
Jason Cholewa, Ph.D., CSCS