Если ГГ стоит то...

function update(delta)
     local cact = db.actor
     local cen = cact:center()
     cen.y = 0
     local cur_speed = 1.e3*cen:distance_to(prev_pos)/delta
     speed_stat[cur_num] = cur_speed
     cur_num = cur_num + 1
     if cur_num == (#speed_stat + 1) then cur_num = 1 end
     local sum = 0.0
     for _,a in pairs(speed_stat) do sum = sum + a end
  speed = sum/#speed_stat
end

local body_states = { -- флажки состояния тела актора
[1]  = "fwd",
[2]  = "back",
[4]  = "l_strafe",
[8]  = "r_strafe",
[16]    = "crouch",
[32]    = "accel",
[64]    = "turn",
[128]    = "jump",
[256]    = "fall",
[512]    = "landing",
[1024]    = "landing2",
[2048]    = "climb",
[4096]    = "sprint",
[8192]    = "l_lookout",
[16384]    = "r_lookout"
}
-- получения флагов состояния тела актора
function actor_body_state()
   local body_state = body_states[db.actor:get_actor_int(nil, 1432)]
   if body_state ~= nil then
    return body_state
   else
    return ""
   end
end

local key_sprint = game.translate_string("key_sprint")

    <string id="key_sprint">
    <text>$$ACTION_SPRINT$$</text>
   </string>