Lacking muscle groups for powerlifters, generally speaking are the hamstrings, upper back, and TRICEPS.
A lot of young bucks, myself included back in the day, whether they want bigger arms or a bigger bench or both, focus on the wrong movements. I built big triceps early on in my powerlifting career, but my bench lockout was still a struggle. It wasn't until I did a few bodybuilding sessions with Dave at the compound that he pointed out the discrepancy in size between my shoulder, upper tricep, and tiny lower tricep.
He showed me walking 1/4 dips and a few other extensions that just crushed me. I was so weak in that isolated range that he and I both knew instantly how right he was.
As I'm getting back to training, I'm experimenting with some finishers to make sure my triceps are well ahead of the game when it comes time to start really benching again - particularly the lower part of my triceps. I've used these Alternating KB Extensions over the last few weeks and they're effective...
They can be done flat or inclined.
You can adjust your elbow positioning, along with the bench height, to avoid elbow pain.
Use light weights and high reps/time under tension to really address the deep muscle fibers in this small muscle group.
Use these as a finisher for 2-3 weeks in a row, either trying to add 5lbs each week, or trying to beat your reps or time from the week before. (Put a 3 min song on and try to go through the whole thing...good luck.)
Also, play around with how you alternate them- every rep, every five reps (shown here), or every ten.
Alternating KB Extensions (done on an incline)
[youtube=http://www.youtube.com/watch?v=p5gdFSne9v0&feature=youtu.be]
