I decided to try a one lift per day workout for a while, where you do 10 - 20 sets of one exercise. I heard that the idea behind this is that because you focus on one muscle for the whole workout, it really breaks down that one muscle (more so than usual) and so all the recovery time gets spent building one muscle.

I tried that today with bench press. I did 15 sets of roughly 10 reps, which took me about 45 - 50 minutes. The thing is, I found that I had to gradually lower the weight as I went through the sets in order to achieve failure at 10 reps, because I was not able to maintain 10 reps at my usual weight for all 15 sets. (I think I started on 70 lbs and finished up on 40 lbs)...Yeah I know that's a weedy weight, but I'm crap at bench press.
My question is, should I be dropping the weight like this? Or should I be trying to stick close to 70 lbs but only capable of lifting a few reps by the end of the workout? (I'm aiming to bulk, not too bothered about strength).

My second question is why do my arms not feel any more exhausted than they usually do? Considering I've hit the same muscles for 15 consecutive sets. (I was resting a minimum of 1 minute after each set, and a max of 3 minutes).

Also, would I be better splitting the 15 sets between 2 different exercises for the one muscle group so that I hit them in different ways? eg. 7 sets of each exercise.

overtraining

it doesn't feel like overtraining though. I'm writing this a few hours after finishing the workout and I feel like I could do most of it all over again.

Isn't it only overtraining when you get really sore or take ages to recover?

if you are going to be doing a one exercise workout then dont do more than 5 reps per lift. meaning, don't go near failure, rack the bar when u got 2 more reps left in you. this will enable you to lift more sets. give yourself 3 minutes in between each set. get up and walk around and shake out.

good luck

one more thing, u can do ladders

say ur doing chin ups and u max is ten

do 1, rest a few seconds, then 2, 3,4,5,6,7,8 then take a minute or 2 off and get back at it, keep doing this until u have trouble doing less a quarter of your target reps. you'll find that you do far more reps than you normally would be able.

example...
i normally do about 30-40 kettlebell true snatches in a work out, with ladders i can 270 reps in about 20 minutes.

give ladders a try, good for size and strength

I'm not a fan of this method, but I have heard about it from people who have done it and also through reading.

It could be that you don't feel any more sore becuase you already get a great workout from your other routine - so why would they? They wouldn't. Course I don't know what your were doing before.

I would be amazed if you could do 10 reps of your max reps. That would be pretty close to amazing. So yeah, you'll have to drop the weight some or use a lower weight that you could do that many times. My vote is for dropping the weight.

Again, I'm not a fan of this method, I'd look into doing something else.

i wasn't lifting my max for 10 reps. my 1 rep max is 130lbs, the 70lbs that I quoted is the weight that makes me max out at 10 reps for the first few sets.

When I said I don't feel sore, that was last night. my pecs are pretty sore today and I can feel a bit of soreness in my triceps.

I think I might switch to doing 2 exercises for each muscle. would it be best to have the 2nd exercise (in the same workout) as a pull if my current one is a push?