#include <sourcemod>
#include <sdktools>
public OnPluginStart() HookEvent("player_jump", Event_PlayerJump)
public Action:Event_PlayerJump(Handle:event, .....)
{
new client_index = GetClientOfUserId(GetEventInt(event, "userid"));
decl Float:finalvec[3];
finalvec[0] = GetEntDataFloat(client_index, GetVelocityOffset_0) * SkillLong[client_index] / 100.0;
finalvec[1] = GetEntDataFloat(client_index, GetVelocityOffset_1) * SkillLong[client_index] / 100.0;
finalvec[2] = 0.0;
SetEntDataVector(client_index, BaseVelocityOffset, finalvec, true);
}