When doing pull-ups (not chin-ups), I find it harder to get up when I look up and my chest is sticking out and back is titled. On the other hand, these harder pull-ups feel more intense and satisfying, for the few reps that I can do. I feel pumped up afterwards.
When I instead just look straight ahead and not look up at the bar, then I find that I can do more pull-ups, more easily.
Is the "proper form" looking up or looking straight ahead, when pulling yourself up?