The first pic is of elk backstrap sinew that has only been cut away from the rest of the loin. When I remove sinew it seldom has this much meat left on it but I am not complaining. In my hand I am holding a piece of slate. On the sinew is a obsidian flake.
The next image shows the actual removal of meat from the sinew. You want to work perpendicular to the sinew, not at an angle. You don't want the tool your using to be very sharp as you can cut the sinew. The longer your sinew is the better it is to work with in most cases. I am simply "pushing" back and forth.
This pic shows the elk backstrap sinew getting cleaner. There is some connective tissue on elk that isn't on deer that I used the sharper obsidian on.
This pic shows the connective tissue on elk that makes meat removal a little harder.
You want to clean both sides of the sinew. You will find that the side of the sinew that faced the dermis of the critter doesn't have all that much to remove but you do want to remove as much of the fascia as possible. Every little bit helps. Any meat or fat left on the sinew can weaken the sinew. This pic shows fascia or connective tissue that you want to remove as much of as you can. Elk especially is very tough when dried out.
I will post the next part on Sunday.