So this has been bothering me for a while, basically every time I try to do a high rep scheme (like GVT) I get a totally different reaction from my upper body workouts than my lower body workouts.
Basically, my upper body workouts seem to work in that by the end of the sets, the muscles are fatigued. I’ve either gone to failure or I feel like I easily could have. With the lower body, it seems like I never stress the muscle because it always turns into cardio-vascular exercise.
The subjective experience is that the lower body workouts are infinitely harder, because of how much more uncomfortable it is to be oxygen deprived vs. muscle fatigue/lactic acid.
Now since the lower body is so much stronger in absolute terms and must require much more energy, I would guess that this must be common. However, I’m usually the only one sweating like crazy and out of breath that I see in the squat rack. The other people seem to experience more of what I experience when I am doing upper body stuff: working the muscle and not their lungs.
To make this more of a mystery, my cardio-vascular system is actually well developed; I routinely run for over an hour at an 7.5 minute mile pace.