diff --git a/examples/stress3.js b/examples/stress3.js
index 3def2e5..4feb37f 100644
--- a/examples/stress3.js
+++ b/examples/stress3.js
@@ -34,9 +34,7 @@ Example.stress3 = function() {
     Render.run(render);
 
     // create runner
-    var runner = Runner.create({
-        isFixed: true
-    });
+    var runner = Runner.create();
     Runner.run(runner, engine);
 
     // add bodies
diff --git a/examples/stress4.js b/examples/stress4.js
index bcbf251..ea8cd9d 100644
--- a/examples/stress4.js
+++ b/examples/stress4.js
@@ -35,9 +35,7 @@ Example.stress4 = function() {
     Render.run(render);
 
     // create runner
-    var runner = Runner.create({
-        isFixed: true
-    });
+    var runner = Runner.create();
 
     Runner.run(runner, engine);