Whenever I do what I THINK is HIIT (recent posts have made me doubt whether or not it was actually HIIT I was doing), I get really exhausted and feel like I can't go hard anymore, but the exhaustion is not the same as I get in cardio. Its more like my legs feel intensely weak, and I have difficulty standing. But I feel like my cardiovascular system could take much more exercise at a more moderate pace. Is this normal?
It just means you have weak legs. Keep at it.
you are weak and lack discipline