A PT told me that flexing my trunk past 65 degrees is dangerous cause past that point all you are doing is hanging on your ligaments. Is this correct? It seems physicaly impossible to do this, but i could be wrong
kill him
kill em all
WTF? Hanging on your ligaments? What does this mean? Your hams are barely even working at 65 degrees.
Tell him he shouldn’t have that rod so far up his ass because it’s touching his brain!
No, he’s wrong. You can also increase the strength of ligaments etc. Gradually build up your strength, you’ll be okay then. Geez, do these people live in the real world?
I think you should hang that PT by his ligaments.
Danger is relative and your PT is more right than wrong, but don’t be so quick to simply ignore/ridicule someone that spent 4+ years of there life learning anatomy, just take what they have to say with a grain of salt is all.
Both my MD and PT(who is young, very well read, and team PT for a pro arena football team(oxymoron?)) said the same thing, once you go past a certain point in trunk flexion, the only thing supporting your spine(lumbar) is the strength of the ligaments hence, the “danger”.
Just to clarify terminology:
When he says “trunk flexion”, he means bending along the spine, not at the hips, right? Toe-touch vs. Good Morning?
I can’t imagine that I would want to spend a lot of time at 65 degree trunk flexion, although i imagine at some point the pelvis must rotate to accomplish any further movement. I just want to make sure I understand what you mean by trunk flexion.
Apologize if this is already established common knowledge - my degrees are in music, not anatomy. 
-Adam
Franks,
That is correct, trunk flexion as in a good morning where you allow the low back to round vs. maintaining neutral spine position.
-sean
AFter I posted I realized my error.
Rounding of the low back is incorrect in good mornings.
So as you had originally commented, trunk flexion as in touching your toes which for most of us requires allowing the low back to round out.