Hello all,
As I enter the last few stages of preparatory exercises, I've noticed a modification to PE1>im has been helping me to straighten my line. It's simple; do the drill standing up.
This exercise has been great for me to help perfect the handstand line. Since I can choose the weight on the barbell, I can stay in this modified im1 much longer than I can stay in a handstand (say 2 minutes, no problem), and I can take my time looking at myself in the mirror to correct the form. The advantage over the normal im1 is simply that my torso is perpendicular to the floor, making it much easier to visual the line of the back. A perpendicular torso also makes it easier to flex the shoulders, allowing me to spend more time in the drill.
Standing up with im1 allows me to spend a lot of time to work on PPT, ribs in, and shoulder flexion, and experimenting with degrees of effort (for example, what happens if I PPT more or less, how does my body compensate if I stick the ribs out). it has overall been great for getting to know my body better. I can focus on the fine details of the HS form and zero in on what part of my body is creating the problem of a bad HS line.
Anyways, hope this idea helps someone. i guess it does not really provide much help if you are still on PE1-6. But for people working on the actual handstand, this modified drill has helped me improve my form by leaps and bounds.