Weight lifting rump, need help breaking plateau please?

Have your spotter put extra resistence on the bar. just as you are about to finish rep. example when you are curlling have him hold the bar in the last few inches so you suddenly have to strain much harder to curl. Should help the muscle fibers seperate more. also make sure you are following regular off days for the muscles to heal.. or the lifting will be a waste.. 2 days lifting 1 day of rest. follow a schedule work on upper one legs the next.. good luck