On gym days where I intentionally train lightly (2 RIR on my 6RM) my brain compensates by forcing me to apply max effort anyway by magically shrinking my 6RM to my 4RM for that session -- how to fix?
Terms/definitions for beginners/lurkers:
6RM for a given exercise/weight combination, you can only perform 6 reps, even if a millionaire offered you a briefcase full of gold bars to hit that 7th rep.
2RIR means 2 "reps in reserve" which means you finish a set 2 reps prior to failure. For example you stop at 8 reps, but you could have gotten 10.
By default, I workout in the mornings about 2-3 hours after waking up. This weird paradox I've been experiencing at the gym all year on my intentionally-light training sessions (i.e. when I want to preserve maximum mental bandwidth for a cognitively demanding task later that day or the next day) is similar in spirit to the following empirical paradox:
- Parkinson's Law states that work expands to fill the time available for its completion
It's like my brain down-regulates my ability summon maximum strength output, which means if I want to leave 2 reps in reserve, I now must subtract 2 reps from the 4RM, which on paper makes it seem like I did 2 of my 6RM with 2RIR rather than 4RIR. It hurts my brain and makes zero sense from a logic/math perspective. I listen to tons of pop-science fitness podcasts, including Huberman. Seemingly, the key concept is intent/pacing and how your intent/pacing drives force production via a neurophysiological explanation that reads like technobabble nonsense when I asked chatGPT about it.
My first question is does this even happen to other people? Or am I just the unlucky one?
My second question is how to fix this problem? Are there any "mental form cues" that can restore my true 6RM? I do everything the exact same way. My pre-gym routine is always the same. (pre-workout powder similar, loud music while driving to the gym, mentally pumping myself up, etc..)
In fact, on my own gym notes, I document whenever my numbers are low (such as a poor night's sleep or had to do my beekeeping in 95-degree summer heat earlier that day). So for my light sessions, I just lie about 2RIR in my workout log rather than blaming "magical, mysterious process which shrank my 6RM to 4RM today".
Update -- upon feeding this post into ai, I should make a possible correction. It's plausible that I could do 2 more reps on my "light days" but I'm in the same agony doing my 4th rep on a light day as my 6th rep on a normal day. So I guess what my question truly should ask is why does my brain dump loads of physical pain/agony into my consciousness on the 4th rep of my light days but waits until the 6th rep on my normal days? And more importantly -- how to fix this stupid agony-dumping mechanism? I hate the fact that on my light days, I walk out of the gym equally mentally exhausted as my normal days, even though I trained at much lower intensity & lower volume. I don't compensate by doing more sets or cutting my rest time between sets. I don't choose my light days because I'm feeling less capable. I choose my light days based on future cognitive tasks and sparing CNS fatigue.

