Amentum

An amentum (Greek: αγκύλη, ankyle,^[1]) was a leather strap attached to a javelin used in ancient Greek athletics, hunting, and warfare, which helped to increase the range and the stability of the javelin in flight. Stability in flight was important because it allowed the javelin to land on its point, which was the only way the throw could be accurately recorded in competition or be useful against a live target. An amentum also increased the effective length of the throwing arm similarly to a spear-thrower or Swiss arrow, which enhances the speed of the projectile.

The javelin was held at ear level and released after a short run. The amentum was looped over the first two fingers of the throwing hand so as to slip off when the throw was made. In competition throwing for distance, including the Ancient Olympic pentathlon at Olympia, Greece, a blunt javelin would be launched at about 45 degrees, but in war or the chase, a sharp weapon was thrown much closer to the horizontal. Javelins and their amenta were used both on foot and from horseback.

The amentum was securely attached at or behind the centre of gravity of the shaft. Attaching the amentum behind the centre of gravity increased the possible distance thrown but reduced accuracy. Hence the amentum was detachable, and the athlete fastened it to suit his taste shortly before use. The winding of the amentum added rotation and therefore accuracy to the projectile, similar to the effect of rifling on a bullet.^[2] The experiments conducted by H. A. Harris support the theories based on vase paintings of the proper use of an amentum.^[3]

In experiments made by General Reffye for Emperor Napoleon III, a javelin that could be thrown only 20 metres by hand could be thrown 80 metres with the amentum. More recent experiments have failed to replicate this level of enhancement, with well-designed tests, showing only a 58% improvement on average.^[4]

The advantages of the amentum are the high precision for fast-flying light javelins, and a less demanding construction than atlatl darts.

استُخدمت أحزمة رمي مماثلة على الرماح الخفيفة في جميع أنحاء أوروبا. استخدمتها القوات الإيطالية والغالية والإيبيرية قبل وبعد الفتوحات الرومانية، وذُكر استخدامها لدى الأيرلنديين في العصور الوسطى، حيث أُشير إلى الحزام باسم "suaineamh" ^[ 5 ^{] .} كما عُثر على بقاياها على الرماح في مكتشفات مستنقع نيدام ، حيث يبدو أن بعضها كان مُثبّتًا بشكل دائم بمسامير. استُخدم جهاز مماثل في كاليدونيا الجديدة ، ولكن في بقية أنحاء العالم، كان قاذف الرمح هو الأداة المعتادة لزيادة سرعة ومدى الرماح الخفيفة ^{[ 2 ] .}