I had the some problem today with DBs
Last week i did two sets 8 with the 75 (weak i know, only been lifting with a serious routine for a little under two years, also im kind of a delt lifter on chest). In the prior weeks, id finish with a set of 8 at 75. This week i couldnt get the 75s up for more than a rep, but i got a good clean set of 8 with 70s. I spent like 20 seconds on just getting the 75s up the first time and wasted a lot of energy (my spotter was pulling up on 1 dumbell while standing next to me, needless to say, he DOES NOT know how to spot).
Im quite pissed now.
I think it was cuz i was sick over most of the weekend. Although, i did legs on Sun and added weight to all my excersizes, my chest sucked balls today.
ill try it again next week