diff --git a/lib/effects/effects.dart b/lib/effects/effects.dart
index f3ca9ff3f..ddc3658bb 100644
--- a/lib/effects/effects.dart
+++ b/lib/effects/effects.dart
@@ -166,7 +166,10 @@ abstract class SimplePositionComponentEffect extends PositionComponentEffect {
     Curve curve,
     bool isRelative = false,
     void Function() onComplete,
-  })  : assert(duration != null || speed != null),
+  })  : assert(
+          duration != null || speed != null,
+          "Either speed or duration necessary",
+        ),
         super(
           initialIsInfinite,
           initialIsAlternating,
diff --git a/lib/effects/move_effect.dart b/lib/effects/move_effect.dart
index 3a65f8a68..0410d9293 100644
--- a/lib/effects/move_effect.dart
+++ b/lib/effects/move_effect.dart
@@ -33,7 +33,10 @@ class MoveEffect extends SimplePositionComponentEffect {
     bool isAlternating = false,
     bool isRelative = false,
     void Function() onComplete,
-  })  : assert(duration != null || speed != null),
+  })  : assert(
+          duration != null || speed != null,
+          "Either speed or duration necessary",
+        ),
         super(
           isInfinite,
           isAlternating,
diff --git a/lib/effects/rotate_effect.dart b/lib/effects/rotate_effect.dart
index 3a23276ac..1dffa79b4 100644
--- a/lib/effects/rotate_effect.dart
+++ b/lib/effects/rotate_effect.dart
@@ -17,7 +17,10 @@ class RotateEffect extends SimplePositionComponentEffect {
     bool isAlternating = false,
     bool isRelative = false,
     void Function() onComplete,
-  })  : assert(duration != null || speed != null),
+  })  : assert(
+          duration != null || speed != null,
+          "Either speed or duration necessary",
+        ),
         super(
           isInfinite,
           isAlternating,
diff --git a/lib/effects/scale_effect.dart b/lib/effects/scale_effect.dart
index c7617838c..ec13695c5 100644
--- a/lib/effects/scale_effect.dart
+++ b/lib/effects/scale_effect.dart
@@ -18,7 +18,10 @@ class ScaleEffect extends SimplePositionComponentEffect {
     bool isAlternating = false,
     bool isRelative = false,
     void Function() onComplete,
-  })  : assert(duration != null || speed != null),
+  })  : assert(
+          duration != null || speed != null,
+          "Either speed or duration necessary",
+        ),
         super(
           isInfinite,
           isAlternating,