Hi Ladies- I’m sort of new to the forum but not to strength training. I had a dilemma tonight while working on a new program.
It called for 3 sets of 5 reps (max set) and this is one day a week which is heavy day. So of course you pile the weight on knowing that you only have to bust out 5. But now my form starts to sacrifice. For example: not squating all of the way down, not chest pressing with a full range of motion etc…
So what do you do? Lighten the weight and feel guilty that you could have easily done 10 more or struggle with the added weight?
BTW, my fitness goal right now is gaining muscle size.
Hmm, I’d say to back down on the weight a bit to where it’s still heavy enough that you almost fail…but not so heavy that your form goes to crap on every set/rep…that’s when injuries happen!
I can see muscling the last rep, maybe…
You struggle, but not to the point form goes bad. Do you have a spotter or a rack. Its okay to fail, that is how progress starts.
With working sets, keep them low enough you keep form, but it is work to keep it. You might lose form with a 1RM, but you shouldn’t with work sets.
Appreciate everyone’s help.
Come to think of it … it’s not really that my form is bad but more that it’s too heavy to complete a full range of motion. Here are a few examples: squat- good form but couldn’t go down to where quads were parallel to the floor, bench press- couldn’t bring the bar all the way to chest on the eccentric motion. I’m limiting my range of motion I think.
I think what I need to do is do a couple light practice reps to mimmick what I’m about to do with heavier weight.
Limiting range of motion= limiting what you can REALLY do!
I mean, I could go in and load the bar with 200lbs for the squat, but personally it won’t mean anything if I don’t complete the whole range of motion…
Don’t limit yourself!! 
I’d say that you need to work on mobility of whatever is holding you back on your form…most likely stretching (Deep tissue, Creasey’s -Magnificent Mobility) I think you will find that not only will your strength increase (Poliquin claims up to 10%, but I’ve never been able to endure the torture that long.) the speed of the rep will increase. Then you can redefine failure to a significant decrease in speed rather than sacrificing form. This way you will stay safe, and continue to make gains. Good Luck!