Underestimate at your own risk.

[Scythe13]

The overall principle, underestimate and there's a good chance you'll become victim.

Bodybuilders know fitness, injury prevention, stretching/flexibility, nutrition, supplementation, and a lot of medication. Those basic skills are more than most cavemen understood, yet they survived. Many bodybuilders can also fight pretty well too.
Instead of focusing on specifics, look at the big picture, there are no-sheeple. I made a list as an example. A rugby player can't climb a tree, blar blar. The specifics are not in question. The issue is that we are dealing with PEOPLE. In a study at some university (can't remember which) they asked them student to rank themselves. Over 90% said they were in the top half of the class for intelligence. As people we HUGELY over estimate ourselves and underestimate everyone else. If you've thought of something new, odds are someone else has had the idea already.

Prep as if you were in the latter 50% of humans in regard to your preps. Always overestimate them and underestimate yourself.