drops sets are brutal, if I was a competitive or aspiring bodybuilder, I would use them about 70-80% of the time.
Years ago, I was doing a squat workout and I did something similar to the Kroc video, though I had been in the 550-615 range for most of my work sets and decided to drop back down to 495 for a final set, I think I got 7-8 reps with it and then I racked it and was hit with a sudden burst of inspiration and frogginess and I asked my spotters to pull of a 45 at each end, and then I backed out and did something like 6-7 reps, racked it, went to 315, then 225 and then to 135, I am embarrassed to say that 135 was the hardest as I could not even feel my legs. I rested for a few minutes, then went into shower and change, tired and wobbly in the lower body, but nothing unusual about that. I went over to my gf's house for the evening--actually her families house and we ate dinner and then sat on the couch to watch tv--maybe Alf, I dont remember and then it hit me, deep cramping aches, I could not get comfortable, I was squirming around, quads would go into violent spasms and everyone asked me what was wrong and I said, something about the workout and they just shook their heads, I was trying to lay down, then lay down with feet elevated, then on my side, fetal position, nothing, I finally excused myself and went home, hot shower, muscle rub, etc, nothing, imagine getting a "charley horse" that lasted about 12 hours, I did not sleep that entire night, just tossed and turned. I hate DOMS the next day, but no worse than usual.
A miserable experience indeed