I didn't watch the linked videos, but I did read the comments : a lot of them recommending Jo work.
In my opinion ... for effective (and I mean real effective) use of a SPEAR ... if you ever (EVER!) turn it around and use the wrong end : you're a complete idiot, or just messing about.
Spear is completely and utterly different to a stick. Deal with it.
How can you make an inaccurate comment without watching the Video's. there are many spears that have a club end. OPEN YOUR EYES and DEAL with THAT!!!!!