My tendency is to be on plane early in the downswing and then suddenly around impact I take a hard left. I believe this is referred to as a broken plane line. When I do this, I notice that my uppper left arm never leaves contact with my upper body. Is this a cause or a result? In other words should I just continue to work on tracing that striaght plane line or consciously work on allowing that left upper arm to come off the chest through impact on to follow thru?