I personally think there’s too much emphasis on
attempting reps that can’t really be done (the half reps), fatiguing, strip sets, dropping weight, etc.
I’d rather see you pick a weight and stick with it. That weight ideally would be around 60% of your 1 rep max early on in a training cycle, and could build up to around 90%.
One way of looking at it that’s quite valid
is the concept of “inroad,” brought forth (to me anyway) by Arthur Jones (someone else may have been first though.) What this means is, as you perform an exercise your muscle loses momentary strength. If you are only just barely
able to complete a rep, or if the weight actually stops, then you can generate a force equal only to the weight.
Let’s say that when fresh you could just barely
complete a rep with 100 lb.
If you exercise with a weight of 80 lb, when you reach your last rep, now your muscle due to fatigue has (momentarily) lost 20% of its strength. As it turns out, this is an excellent value for triggering strength and hypertrophy gains.
What if instead you work out with a weight of 40 lb? Then at the point you stop – assuming you continue to where you can do no more reps – your muscle has (at the time) lost SIXTY percent of its strength. This amount is NOT good for strength or hypertrophy gains.
Or what if you do as aerobics women like to do, and train until you’re so weak you can no longer lift a pink dumbbell, exhausting say 90% of your strength? Forget gains!!!
My recommendation is, don’t use weights below 60% 1RM except if, on a particular exercise, warmups with light weights are beneficial to you. And in this case, still don’t fatigue yourself down to such a low weight. Do rather few reps with the light weight. Several warm-up sets if necessary, but not high reps.