I walked into in the sparsely-adorned weight room and began my warmups. Using the empty bar to practice the best upper body exercise, I thrust the iron into the air enthusiastically so I could add weight and begin my actual routine. I put the bar down and was adding weights when I heard a mousey voice behind me:

“You shouldn’t lock out your elbows”

Me: “What?”

I looked around to see a chubby girl in a “personal trainer” T-shirt glaring at me.

Girl: “It’s bad for your cartilage. You’ll hurt yourself”

My inner monolgue was ready with several snide responses, but luckily I am well-socialized enough to hold my tongue in polite company when I have nothing to gain from the situation.

Me: “Okay. Thanks. By the way, do you have a squat rack?”

Girl: “What’s that?”

Now, if this girl had even a remotely decent physique, I might have given her the benefit of the doubt and done a 10-second internet search on proper overhead press form. But, rightly or wrongly, I had developed my form from fit friends and books written by people who have actually achieved level of fitness that I respect. I wasn’t about to take fitness advice from someone who hadn’t lifted a weight or gone for a jog since the second Bush administration.

The idea that someone who didn’t know what a squat rack was would be giving advice about weightlifting was especially laughable. I let her say her piece, and summarily dismissed her existence from my life. If you are setting out to accomplish anything that requires long, sustained effort, the one principle you must follow is:

Only take advice from those who have done what you want to do

“Bro science” is something we see lampooned on a daily basis. People trash “meatheads” and “gurus” and suggest that everyone avoid innovative or non-scientifically approved methods to achieve a goal. With large swaths of published experimental science now being revealed as non-reproducible, it is becoming clearer each day that peer-reviewed science has essentially devolved into academia-approved bro science. We are seeing results-based and evidence-based advice supplanted by credentialism and political correctness. No wonder everyone is fat, unhappy, poor and sick.

This principle may seem obvious, but it is astonishing at how many people fail to adhere to it. Take dating for example — the internet abounds with female dating coaches and advice columnists who presume to tell men how to attract and please women. None of them have ever done this themselves, and it’s no coincidence that their advice is almost universally worthless.

Whether you want to get huge, write a book, travel the world, get a promotion, date hotter girls, or start a business, you must only take advice only from those who have accomplished what you want to do. Your mentorship and guidance must come from those who made mistakes along the way and lived to tell the tale. Anything else isn’t worth the paper it’s printed on.

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