So your starting out on the bench press and your aim is 3 sets. Your new to this exercise and don't know what weight you can lift so you do a warm up set with the bar (this doesn't count towards the main sets) it's dead easy and you do 15 easy reps.

No problem...So now what weight do you lift next? As with everyone who is new to an exercise there is guess work, so you add 10kg either side. You do 15 easy reps, should you stay on the weight or increase it? Most definitely increase it as the previous set was too light. You add another 10kg either side, 40kg all together and fail at 11 reps, but this time getting to those 11 reps was a lot more taxing, you just about squeezed out the 11th rep but it was hard.

Again should you add more weight to your 3rd and final set? Say you do and you add another 10kg either side 60kg in total. You do your last lift but this time you only get 6 reps.

Should you stay on this weight? Well you could do but you failed at 6 reps. Don't get me wrong there are benefits from training this way.

So you take 10kg off either side, so now your back down to 40kg, again you do your 3rd set but this time you only managed 9 reps.

Make a note of this in your diary as you will need it.

Nest session, do you up the weights or stay as you are? Well you got 15-11-9 reps. So no, you stick to 40 kg and see if you can get as close to 12-12-12 on all 3 sets. If not and you get 12-12-10 then you carry on with the same weight until you reach 12-12-12 for all 3 sets.

When you complete 12 reps on all 3 sets demonstrating control, then you can up the weights.

Hope that made sense.