just looked again - your posture changes like about half way.
at the start, your all Front Side mechanics without doing any triple extension
then at half way, your all rear side mechanics… most of my above post was on your 2nd half.
for the 1st half, you have to learn to get much lower angles and keep from your shoulders down to your ankles in a straight line whilst keeping tight angles to the ground. - hills, med balls, sleds