Don't Attack the Low Back
There's one very common mistake I see in a lot of strength athletes' programs – extra low-back work. They have absolutely zero awareness of just how much work their erectors are already doing.
If you're squatting, deadlifting, and doing standing overhead presses, then your low back is getting a metric butt-ton of work; not even indirect work, but very direct work.
The erectors recover more slowly than any other muscle group, yet guys will do all of the above and then decide to throw in a bunch of barbell rows, T-bar rows, hypers, and a whole slew of other movements where the erectors have to contribute mightily.
I can't tell you how many strength athletes had their squat and deadlift climb up once I removed all of the extra spinal-loading movements. The fact is, fatigue will mask fitness.
The best thing you can do is choose exercises where you give the low back a break from loading while working the musculature around it so that it has a stronger support structure. That's where the chest-supported row comes in.
There are countless variations of this machine, but virtually any of them can be a strength athlete's best friend.
It allows you to really smash the entire upper back while giving you a break from more axial loading. Many times this is exactly what you need to get past a plateau.
I like the seated machines rather than the ones where you're lying at a 45-degree angle because the natural tendency on those is to arch very hard once the loading gets heavy, which defeats the whole purpose of choosing the chest-supported version.
If you don't have access to the seated machine, rig up your own with an incline bench and a low cable. The best bar to use in this situation is one with a curve in it so you aren't banging it into the bench and can get your elbows behind you far enough to get a strong contraction in the upper back.
Loading on chest-supported rows is secondary to achieving a strong mind-muscle connection. If you want to really get a smoke show going, do them after your deadlifts. You should feel an immensely strong contraction in the upper back due to the maximal loading and increased neural output that came from the deadlift.
Don't rip the weight on the initiation phase. Pull with a "roll on" rep fashion where you initiate with the upper back in a very deliberate manner and then pull aggressively into the strong peak contraction. Hold that puppy for a second before lowering.
Two to three sets of 10-12 reps will do the job.