All you need to know about the evolution of Javelin Throw

The men's javelin was redesigned in 1986, such that the centre of gravity was moved 4 cm (1.5748 inches) forward. The step was mainly taken because the male throwers were in danger of crossing the space available for the javelin throw in stadiums and entering the track space, thereby endangering other athletes and officials.

All you need to know about the evolution of Javelin Throw
The men's javelin was redesigned in 1986, such that the centre of gravity was moved 4 cm (1.5748 inches) forward. The step was mainly taken because the male throwers were in danger of crossing the space available for the javelin throw in stadiums and entering the track space, thereby endangering other athletes and officials.