For too long I was a no pain no gain guy. Older, wiser and sorer now and trying to looking after myself better I wonder, that if lets say my goal for military press is 50kg by 12 (bodyweight 75kg), If I lifted easy and got to the point could lift 40kg by 12 effortlessly, would that not equal to me doing 50kg by 12 hard? and would I not get the same hypertrophy results.
For shoulder muscle size, find lifts that you can push “hard,” that don’t hurt you. You want that bust-ass feeling of effort and tension on the muscle to grow.
If barbell pressing hurts when you give solid effort, so you can’t really give a solid effort, it might be not a great lift for size.
A real smooth and easy 40 x 12 might demonstrate similar strength to an ugly 50 x 4.
10 kg is a lot in the press. Especially for those not pressing 100+ kg. Some may be able to do 40 kg close to effortlessly, and get 3-4 with 50 kg (depends on the subjective meaning of effortlessly). Big Z can do 12 with 40 kg without much effort at all, and can perhaps do 100 reps with 50 kg.
Basically your question comes down to what you mean by effortlessly. It is effortless for nobody. It is low effort for some, very very low for others, hard, impossible for others. I could easily do 12 with 40 kg, and could do 12 with 50 kg and it would be harder for me.
Just looking at this at a percentage perspective and the 2% rule:
If I can squat a 1 rep max with 500 lbs, I should be able to do 10 reps with 400 lbs. Now 20% (from 50kg to 40kg is a 20% reduction) of 400 lbs would be a reduction of 80 lbs, or 320 lbs.
Would squating 320 lbs for 10 reps easily be the same a squating 400 lbs hard? You’re squating 65% of your 1 rep max. That would make a nice “working rest” workout. IMO, the percentage drop is too much to get a similar result.
I think @FlatsFarmer nailed it - why not find something you can push hard on without getting beat up? I think that’s the unrecognized “rule” of hypertrophy. Side raises > overhead press where overhead press = pain. Come at me, mathematicians!
What happens if you can lift 40kg for 12 at normal speed, then you try your next goa of 30kg with a
Edit: not sure why this didn’t post the whole thing I wrote.
What I wanted to write was that to to lift 40kg for 12 normal speed reps, you could try lifting 30kg at a slow tempo. If you can shift 30kg for 12 5 second lowers then that might help you control 40kg better.