PrinzII- Oh well, think of it as more recovery time. Now you can REALLY get in a good workout.
BTW, if your pull-downs are getting your ARMS sore instead of your LATS, uh, we might want to work on your form there. I always think of my arms as just "hooks" that connect the weight (the pull-down bar) to the muscles I'm working (my lats). It's kinda hard to explain..but that never stops me
And besides, it's back-day for me when I log off, so this'll get me psyched.
Pull-downs: Generally, use a pronated (palms down) or neutral (palms facing each other- takes a special bar) grip. NOT a supinated (palms up) grip. This will help keep the biceps out of it and help you focus on your lats.
Don't lean back, sway, or otherwise use body english. Don't hunch your shoulders. Try to imagine touching your elbows together behind your back.
If you have a training partner/spotter there, have him/her GENTLY "karate chop" your lats while you're doing the exercise. You'll feel his contact in the muscles you're trying to work and better feel whether you're targeting them or not (my wife found this especially helpful).
Work sorta slow. Don't jerk the bar down from the top position, and hold it for a second when you've pulled it down all the way. Have the bar go back up slower than you pulled it down. If you can't do the reps smoothly and slowly, drop the weight a bit until you can.
Inhale as the bar goes up, exhale as you pull it down (breathe OUT when you're "working").
Rep-wise, you'll eventually want to do far fewer than 50 reps per set, even given your specific goals. If tightening your form drops you down to 20 reps per set (or even less), that would be more like it. Otherwise, do each rep slower or maybe UP the weight. More than 20 reps (and/or sets that last much more than 2 minutes) aren't right for the fast-twitch muscle fibers that make up your lats (and most of your muscles), even when you're working on
endurance. Better to do shorter sets and rest for shorter intervals between them.