The Eskimos also made sinew-backed bows but in their frigid and damp climate it was impossible to do anything with glue, so their sinew was applied in the form of twisted cordage tied on the back of the bow. The tension in the backing material was increased by twisting after it was bound to the back of the bow.
Baugh,D.(1994). A note on indian bow making or the secrets of sinew revealed. The Bulletin of Primitive Technology, Vol. 1