When you jump you can sometimes jump to the player on the head, that brow on which you jump is damaged (and the bolshii you it will be the less hp he outlier) (and if you ubivash another player, you get one frag).
To kerf plug - amx_headsplash 1
cut - amx_headsplash 0

You can change the maximum damage on the jump:
* Define MAXIMUM_DAMAGE_FROM_JUMP 70.0