diff --git a/code/modules/mob/living/carbon/human/human_movement.dm b/code/modules/mob/living/carbon/human/human_movement.dm
index b286bc7f760..39bdd785530 100644
--- a/code/modules/mob/living/carbon/human/human_movement.dm
+++ b/code/modules/mob/living/carbon/human/human_movement.dm
@@ -46,7 +46,7 @@
 	tally += 2*stance_damage //damaged/missing feet or legs is slow
 
 	if(RUN in mutations)
-		tally -= 1
+		tally = -1
 	if(HULK in mutations)
 		tally += 1
 	if(status_flags & IGNORESLOWDOWN) // make sure this is always at the end so we don't have ignore slowdown getting ignored itself