But you do TRY for what's on the program when you lift. Because the point is to lift more weight (Even if you just want to get swole the mechanism for doing that is lifting more weight). Sometimes you don't get it, sometimes it's easier than you expected. But the weight lifted is the work done regardless of how it felt. And the power you put out is the speed you go (assuming your weight doesn't change mid ride)
RPE is still relevant. If your RPE for the scheduled interval is higher than expected or if you fail to achieve the intervals scheduled you may be getting sick. You may not be ready for the increased workload. Maybe you didn't eat enough to perform well. So you adjust your training from there. But if you only use RPE you don't know where your "there" is.
At least that's how I do it. I will admit that approaching intervals on the trainer with progressive overload in mind is directly affected by my days lifting heavy. So maybe it's not the best way but I am getting faster.
RPE is still relevant. If your RPE for the scheduled interval is higher than expected or if you fail to achieve the intervals scheduled you may be getting sick. You may not be ready for the increased workload. Maybe you didn't eat enough to perform well. So you adjust your training from there. But if you only use RPE you don't know where your "there" is.
At least that's how I do it. I will admit that approaching intervals on the trainer with progressive overload in mind is directly affected by my days lifting heavy. So maybe it's not the best way but I am getting faster.