Side Lever PE question

I have been wondering for a little while why the basis of Side lever progressions are all lower back strength exercises.  I am happy to work them and I know that Coach Sommer has a very good reason for programming the course in this way, but I'm surprised that side lever work is founded on lower back exercises.

What role do the lower back muscles play in a side lever?  I've never done one but I always thought the majority of the work was being done in the shoulders/lats/obliques/hips.  I'd love to know more about this position and how the back helps support it.

Again - I'm not complaining or feeling at all impatient about progressing past these exercises, just wondering.

Part of it is to balance out the core work being done with the front-lever. 

Part of it is that the lower-back and core muscles both work as stabilizers in a side-lever; you need good strength on both sides to keep your torso straight and steady. 

Part of it is that, apart from its utility in performing side-levers, lower-back strength is fundamental, so it has to come somewhere. 

I've been trying to search up on what is a Side Level, but could not find, i know whats a front and back level, so what is a Side Level?

Andrew Tan said:

I've been trying to search up on what is a Side Level, but could not find, i know whats a front and back level, so what is a Side Level?

First of all - it's a side "lever" not a side "level".  This is is a side lever - also known by some as a human flag.