Amentum

An amentum was a leather strap attached to a javelin used in ancient Greek athletics, which helped to increase the stability of the javelin in flight. Stability in flight was important in javelin competitions because it allowed the javelin to land on its point, which was the only way the throw could be accurately recorded.

The amentum was attached either permanently or freely wound around the middle of the shaft. Each technique gave the thrower different benefits. In warfare, the amentum was permanently attached to give the throw more force and accuracy. In athletic competition, the amentum was freely wound around the shaft, held in place by a stud. The winding of the amentum added a spiraling effect, similar to that of a bullet. The experiments conducted by H. A. Harris ("Greek Javelin Throwing") support the theories based on vase paintings of the proper use of an amentum.

The javelin was held at ear level, parallel to the ground, and released after a short run. The amentum was looped over the first two fingers of the throwing hand. A good throw required the amentum to slip off the fingers, reducing drag and enhancing speed.