Substitute exercises for medical reasons

[metaloid]

Let me clarify. I used rep ranges as a way to gauge weight. I think that in a way we are both saying the same. One has to load enough weight so that the exercise is challenging, without the form breaking down. Weight that is challenging for 5 good reps is heavier than weight that is challenging for 8 reps. So overall in the 8-12 reps the weight will necessarily be lighter, applying less intra-abdominal pressure over every rep.
Given that at heavy weights (5 reps) his body tilted in a way that exactly tried to counterbalance the lack of muscles, it seemed that heavier would just worsen the situation.

As for your last point, it may be more endurance-like, but it never goes above 12 - it usually stays around the 8-10, so it's not an extreme range like +15.

I'll add that we also kept in mind the doctor's recommendation, so we preferred to err on the safe side, considering that the consequences in this particular case could be much worse than a sore muscle for a few days.

[SouthernLifter]

We have past the first quarter of the 21th century and these people still continues with the silly rep ranges stuff.

I am getting sick.

[Maybach]

Unless he has gone through an NLP, and is a thorough intermediate, the difference between the weight for a set of 8 and a set of 5, with the assumption that both are calibrated to be sufficiently stimulative, will not be relevant to the question of intrabdominal pressure.

Say his 8 is, what, 30 pounds lighter than his 5? This is two weeks of progress. He is going to be doing the weight you would have started him on for fives for three more reps in two (maybe 3 or 4 to be conservative) weeks. If it was going to bust him open today, it will bust him open in two weeks just the same. Those three reps are not the issue. Just have him progress his fives.