Additional threads may also be laid in at the nocking points for the bow stave and for the arrow, which are sites of likely wear.
Modern strings are often made as a single continuous loop: this is then served to give the final form.
Disadvantages include the lesser amount of fiber at the ends, where wear is most likely; this may be overcome by serving the string.
In many parts of Asia, traditional strings have a single loop in the center, with the ends made of separate lengths tied on using a special knot.
Traditional materials include linen, hemp, other vegetable fibers, hair, sinew, silk, and rawhide.
[5] Njál's saga describes the refusal of a wife, Hallgerður, to cut her hair to make an emergency bowstring for her husband, Gunnar Hámundarson, who is then killed.
They include: Dacron (strength per strand = 22.5 kg (50 lb), stretch = 2.6%), a commonly used polyester material.
Liquid crystal polymers such as Kevlar and Vectran (strength per strand = 31.8 kg (70 lb), stretch = 0.8%) are polymer materials with a higher density and smaller diameter than Dacron, which results in a faster arrow speed (approximately 2 metres per second (6.6 ft/s) faster).