Is Bending the Bar in Powerlifting an Effective Technique?

[PhysicsKush]

I was wondering , in power lifting , if while doing the deadlift the bar that's holding the two masses bends , is he actually lifting up 100% of the theoretical weight or say about 70-90% of it ? Because i tought , if there's at a certain point ,a force pushing the two weights down, could that make it less heavy for a split second or more?

 

[Simon Bridge]

Welcome to PF;
As long as the weights are not being supported by anything other than the lifter, then the lifter is supporting the entire weight of the bar + weights.
The force pulling the weights down is called gravity. To lift the weights at a constant speed, the lifter must provide at least equal force in the opposite direction - but to accelerate the weights (i.e. to start them moving at the beginning of the lift) the lifter needs to provide more force.
There are techniques exploiting the way the body works that can make lifts easier - but bending the bar is not one of them.

You can look up "physics of weightlifting".