I've noticed that I can flex my right bicep/arm with no/minimal forearm contraction. With my left bicep, I need to flex my forearm and surrounding muscles (pecs, etc.) really hard to get the bicep to fully contract.
My right arm is my dominant arm. So why is this? What can I do to be able to isolate my left bicep? Basically I feel as if I don't have 'full control' over it. Hell, I feel like my left arm is 3x weaker than my right.