Can Your Brain Detect a Lopsided Barbell?

Is the brain capable of detecting small imbalances in a loaded barbell? Does it matter that the plates match on each side? Science takes a look at what happens when you load the barbell all crazy.

Today’s study has a special place in my heart. First, it studies the bench press. All great scientific studies must involve the bench press and therefore be done on Mondays. But next, it takes a common weight room faux paus, incorrectly loading one side of a barbell, and seeks to understand what happens when you lift it. The science of screwing up – I love it!

The study involved 35 men from age 19-34 with at least five years of experience on bench press. They were taken to the bench, blind-folded, given earmuffs, and then proceeded to bench press three different bars in a random order. After each bar they were asked, “Balanced or unbalanced? If unbalanced, which side was heavier?”

Here are the three bars they lifted:

  1. Balanced bar with 135lbs total made from a 45lb plate on each side.
  2. Bar with 135lbs total made from a 45lb plate on one side and a bunch of tiny 2.5lb plates on the other.
  3. Unbalanced bar with a 45lb plate on either side and a 2.5lb plate added to one side.

The results? The group didn’t bat an eye (albeit blindfolded) at the perfectly balanced bar. No surprise there. Furthermore, the group didn’t consistently identify the unbalanced bar with the extra 2.5lb plate on one side. But the group did consistently identify the bar with the big plate on one side and all the tiny plates on the other. This was due to the difference in the center of gravity, as all the tiny plates shifted the center of gravity by over three inches.

The conclusion: At sub-maximal loads, detecting small imbalances in a barbell is pretty difficult. The results could have been different at loads closer to 1RM. Even though we don’t learn a lot of practical information from this one, it’s an interesting study of something we’ve all experienced. Plus, it gives us the mental image of a grown man fully outfitted with a blindfold and earmuffs, bench pressing a bar with one large plate on one side and a bunch of tiny plates on the other. For me, that alone was worth it.


1. Piper, Timothy, et. al. Dynamic Balance Abilities of Collegiate Men for the Bench Press. Journal of Strength and Conditioning Research 26:12, 3225-3229, Dec 2012.

Photo courtesy of Shutterstock.

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