Why Can't I Lift More with a Barbell Than Dumbbells?

[AFG34]

If i can do 40 pounds with each hand with dumbells, then how come i can't do 80 pounds using both hands with a barbell?
I am sorry if this is in the wrong section, please feel free to move it.

 

[G01]

Well, when you say 40lbs, do you mean that you have 40lbs of weight hanging on the dumbells, or do you mean 40lbs including the dumbells? If you mean the former, then it may be that the barbell simply weighs more than the two dumbells put together.

Another issue may be the way you hold the barbell and dumbells. Lifting weight with different ways of holding it may work different segments of muscle or put more strain on a muscle than the other method of holding the weight. This can affect your ability to lift the weight as well.

 

[AFG34]

interesting answer...thanx

 

[russ_watters]

Generally, people can curl more with a barbell than with dumbells because the bar stabilizes the muscles. The same goes for a bench press vs dumbell press.

It is a structural thing - the more constrained the motion is, the stronger the structure.