diff --git a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/MovingConfig.java b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/MovingConfig.java
index 6f3c2a66..be260b56 100644
--- a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/MovingConfig.java
+++ b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/MovingConfig.java
@@ -121,6 +121,7 @@ public class MovingConfig extends ACheckConfig {
 	public final int 		velocityGraceTicks;
 	public final int		velocityActivationCounter;
 	public final int		velocityActivationTicks;
+	public final boolean	velocityStrictInvalidation;
     public final double     noFallyOnGround;
     public final double     yOnGround;
 	public final double     yStep;
@@ -191,6 +192,7 @@ public class MovingConfig extends ACheckConfig {
         velocityGraceTicks = config.getInt(ConfPaths.MOVING_VELOCITY_GRACETICKS);
         velocityActivationCounter = config.getInt(ConfPaths.MOVING_VELOCITY_ACTIVATIONCOUNTER);
         velocityActivationTicks = config.getInt(ConfPaths.MOVING_VELOCITY_ACTIVATIONTICKS);
+        velocityStrictInvalidation = config.getBoolean(ConfPaths.MOVING_VELOCITY_STRICTINVALIDATION);
         yOnGround = config.getDouble(ConfPaths.MOVING_YONGROUND, 0.001, 2.0, 0.0626); // sqrt(1/256), see: NetServerHandler.
         noFallyOnGround = config.getDouble(ConfPaths.MOVING_NOFALL_YONGROUND, 0.001, 2.0, yOnGround);
         // ystep is set to 0.45 by default, for stairs / steps.
diff --git a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/SurvivalFly.java b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/SurvivalFly.java
index 7990321b..af9b3119 100644
--- a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/SurvivalFly.java
+++ b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/moving/SurvivalFly.java
@@ -549,7 +549,8 @@ public class SurvivalFly extends Check {
         }
         
         // Check removal of active horizontal velocity.
-        if (hDistance <= hAllowedDistance){ // TODO: Check conditions etc.
+        if (hDistance <= (cc.velocityStrictInvalidation ? hAllowedDistance : hAllowedDistance / 2.0)){
+        	// TODO: Should there be other side conditions?
         	// Invalidate used horizontal velocity.
 //        	System.out.println("*** INVALIDATE ON SPEED");
         	data.hVelActive.clear();
diff --git a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/ConfPaths.java b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/ConfPaths.java
index 33f9a684..5f421de7 100644
--- a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/ConfPaths.java
+++ b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/ConfPaths.java
@@ -565,6 +565,7 @@ public abstract class ConfPaths {
 	public static final String  MOVING_VELOCITY_GRACETICKS				= MOVING_VELOCITY + "graceticks";
 	public static final String  MOVING_VELOCITY_ACTIVATIONCOUNTER		= MOVING_VELOCITY + "activationcounter";
 	public static final String  MOVING_VELOCITY_ACTIVATIONTICKS			= MOVING_VELOCITY + "activationticks";
+	public static final String	MOVING_VELOCITY_STRICTINVALIDATION		= MOVING_VELOCITY + "strictinvalidation";
 
     public static final String  MOVING_NOFALL_YONGROUND                  = MOVING_NOFALL + "yonground";
     public static final String  MOVING_YONGROUND                         = MOVING + "yonground";
diff --git a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/DefaultConfig.java b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/DefaultConfig.java
index 307e1189..e5dc409f 100644
--- a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/DefaultConfig.java
+++ b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/config/DefaultConfig.java
@@ -443,6 +443,7 @@ public class DefaultConfig extends ConfigFile {
         set(ConfPaths.MOVING_VELOCITY_GRACETICKS, 20);
         set(ConfPaths.MOVING_VELOCITY_ACTIVATIONCOUNTER, 80);
         set(ConfPaths.MOVING_VELOCITY_ACTIVATIONTICKS, 140);
+        set(ConfPaths.MOVING_VELOCITY_STRICTINVALIDATION, true);
         
         // General.
         set(ConfPaths.MOVING_TEMPKICKILLEGAL, true);