The reason for the question is this-
I know what rep work feels like for me. I key on feeling my heels just kicking my butt a touch on the first few strides of rep work, then I focus on a forward lean, driving my arms with a fair amount of energy and focusing on being up on my toes. My breathing will be a non-issue for the first 100m, then will become increasingly labored so that I will be breathing pretty heavy if I go 400m, but not 200m. My cadence will increase and will have a "tap, tap, tap, tap" rhythm to it, which ends up at about 190-200 spm.
I know what 5k pace feels like. I key on being up on my toes a bit, with a long and open stride and quicker turnover than easy distance pace, but if I kick myself in the butt with my heel, I know I am going way too fast. Arm swing will be with some added effort, but not much. Breathing will be easy for first 400m, then will grow increasingly labored until it reaches your typical end of race breathing pattern 800m-1000m into the interval. My cadence will definitely be crisper than easy distance, but not like it is on rep work, which turns out to be about 180 spm.
I know what threshold pace feels like. I key on keeping my stride open and maybe being up on my toes early on to open up that stride, but then settle into a foot strike that is more like my easy distance pace foot strike. My arm swing is relaxed without any additional energy added, but with a focus on a clean swing. My breathing should remain like easy distance breathing the first 400-600m, and gradually increases in intensity over the course of the effort with my breathing patter eventually moving away from my easy distance breathing pattern to something other than that and other than my 5k race day breathing pattern. If I am doing cruise intervals and find myself breathing the way I do during a race, I remind myself to relax my breathing first and let that dictate the pace. If I am doing a continuous tempo run, I do the same thing for the first 10 minutes, and then recognize that I might end up closer to race day breathing over the last 5 to 10 minutes of the effort. My cadence, despite being up on my toes a little early and because of the relaxed arm swing, is quicker than my easy distance cadence, but slower than my 5k cadence and turns out to be in the low to mid 170s.
But for "marathon race day effort," my breathing would be the same as my easy distance breathing patterns. My arm swing would be the same as my easy distance arm swing. My stride would elongate some, but I would never be up on my toes at all nor would I ever come close to kicking myself in my but. The only thing that would be notably different than on my easy distance pace runs, other than pace, is that my cadence will end up close to my threshold effort cadence (which really is a function of pace, and not really an "input" itself for me.
And I think most people, if they listened to their bodies during workouts, would be able to point to similar cues from their bodies for most effort levels, but would struggle to be able to point to body cues associated with marathon effort.