diff --git a/Data-1.13/Ja2_Options.INI b/Data-1.13/Ja2_Options.INI
index 318e1bd97..e91d7e87c 100644
--- a/Data-1.13/Ja2_Options.INI
+++ b/Data-1.13/Ja2_Options.INI
@@ -2074,8 +2074,9 @@ CAN_CLIMB_ON_WALLS = TRUE
 ; ----------
 ; 
 ; MAX_BACKPACK_WEIGHT_TO_CLIMB is the maximum weight a backpack can weigh and still allow you to climb with.
+; This value does not consider the weight of the backpack's content.
 ; 
-; - weight of backpack = <ubWeight> of backpack-item in items.xml
+; - weight of empty backpack = <ubWeight> of backpack-item in items.xml
 ; - if MAX_BACKPACK_WEIGHT_TO_CLIMB is equal or higher than <ubWeight> = climbing allowed
 ; - range 1-100 (10 = 1kg, i.e. TIMS <ubWeight> 35 is 3.5kg in game)
 ; - if MAX_BACKPACK_WEIGHT_TO_CLIMB is -1 (default), the option is unused
@@ -2122,12 +2123,12 @@ CAN_CLIMB_ON_WALLS = TRUE
 ;
 ; - climb, but restrict backpacks over certain weight limit:  
 ;                                                             
-; MAX_BACKPACK_WEIGHT_TO_CLIMB = 50 (example value: climb, but not if backpack is over 5 kg)
+; MAX_BACKPACK_WEIGHT_TO_CLIMB = 50 (example value: climb, but not if empty backpack is over 5 kg)
 ; USE_GLOBAL_BACKPACK_SETTINGS = FALSE
 ;
 ; - no climbing, except for backpacks under certain weight limit: 
 ;
-; MAX_BACKPACK_WEIGHT_TO_CLIMB = 5 (example value: don't climb if backpack is over 0.5 kg)
+; MAX_BACKPACK_WEIGHT_TO_CLIMB = 5 (example value: don't climb if empty backpack is over 0.5 kg)
 ; USE_GLOBAL_BACKPACK_SETTINGS = TRUE
 ;
 ; default:
@@ -2144,6 +2145,34 @@ CAN_CLIMB_ON_WALLS = TRUE
 MAX_BACKPACK_WEIGHT_TO_CLIMB = 5
 USE_GLOBAL_BACKPACK_SETTINGS = TRUE
 
+;------------------------------------------------------------------------------------------------------------------------------
+; When moving with a backpack, the weight of the backpack + its contents can slow down your mercs
+; Movement per tile is slowed down by an additional AP cost up to AP_MODIFIER_PACK (Default in APBPConstants.ini is 4)
+; That means that when a merc walks with a heavy backpack instead of needing 8 APs, they may need up to 12 APs to move a tile
+; The additional AP cost is calculated by weight of the backpack including its contents / BACKPACK_WEIGHT_FACTOR rounded down
+;
+; Each step for value BACKPACK_WEIGHT_FACTOR represents 100 g. This means for example:
+; BACKPACK_WEIGHT_FACTOR = 50 represents 5.0 kg (50 * 100 g)
+; The tables below assume that the relevant default values are used
+; 
+; Backpack weight including contents    | AP Penalty per Tile
+;   < 5.0 kg                            | + 0
+; >=  5.0 kg                            | + 1
+; >= 10.0 kg                            | + 2
+; >= 15.0 kg                            | + 3
+; >= 20.0 kg                            | + 4
+;
+; The value BACKPACK_WEIGHT_FACTOR will also change AP costs for stance changes (prone<->crouching<->standing)
+; For this purpose only one threshold is considered
+;
+; Backpack weight including contents    | AP Penalty per stance change
+;   < 5.0 kg                            | + 0
+; >=  5.0 kg                            | + 1
+;------------------------------------------------------------------------------------------------------------------------------
+
+BACKPACK_WEIGHT_FACTOR = 50
+
+
 ;------------------------------------------------------------------------------------------------------------------------------
 ; Show enemy weapon name, armour and head items in tactical
 ;------------------------------------------------------------------------------------------------------------------------------
diff --git a/INIEditorJA2Options.xml b/INIEditorJA2Options.xml
index 1e3c2caeb..822139806 100644
Binary files a/INIEditorJA2Options.xml and b/INIEditorJA2Options.xml differ