diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PlayerLoopSystemEnum.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PlayerLoopSystemEnum.cs
new file mode 100644
index 0000000..0d03e03
--- /dev/null
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PlayerLoopSystemEnum.cs
@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Cysharp.Threading.Tasks.Internal
+{
+    public enum PlayerLoopSystemEnum : int 
+    {
+#if UNITY_2020_2_OR_NEWER
+        TimeUpdate,
+#endif  
+        Initialization,
+        EarlyUpdate,
+        FixedUpdate,
+        PreUpdate,
+        Update,
+        PreLateUpdate,
+        PostLateUpdate,
+    }
+}
diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PlayerLoopSystemEnum.cs.meta b/src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PlayerLoopSystemEnum.cs.meta
new file mode 100644
index 0000000..5013a18
--- /dev/null
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PlayerLoopSystemEnum.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 82c7d0801384e6843a0cc6811570ca91
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs
index 508e24e..16c1005 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs
@@ -291,43 +291,43 @@ namespace Cysharp.Threading.Tasks
             var copyList = playerLoop.subSystemList.ToArray();
 
             // Initialization
-            copyList[0].subSystemList = InsertRunner(copyList[0], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldInitialization), yielders[0] = new ContinuationQueue(PlayerLoopTiming.Initialization),
+            copyList[(int)PlayerLoopSystemEnum.Initialization].subSystemList = InsertRunner(copyList[(int)PlayerLoopSystemEnum.Initialization], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldInitialization), yielders[0] = new ContinuationQueue(PlayerLoopTiming.Initialization),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastYieldInitialization), yielders[1] = new ContinuationQueue(PlayerLoopTiming.LastInitialization),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerInitialization), runners[0] = new PlayerLoopRunner(PlayerLoopTiming.Initialization),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastInitialization), runners[1] = new PlayerLoopRunner(PlayerLoopTiming.LastInitialization));
             // EarlyUpdate
-            copyList[1].subSystemList = InsertRunner(copyList[1], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldEarlyUpdate), yielders[2] = new ContinuationQueue(PlayerLoopTiming.EarlyUpdate),
+            copyList[(int)PlayerLoopSystemEnum.EarlyUpdate].subSystemList = InsertRunner(copyList[(int)PlayerLoopSystemEnum.EarlyUpdate], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldEarlyUpdate), yielders[2] = new ContinuationQueue(PlayerLoopTiming.EarlyUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastYieldEarlyUpdate), yielders[3] = new ContinuationQueue(PlayerLoopTiming.LastEarlyUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerEarlyUpdate), runners[2] = new PlayerLoopRunner(PlayerLoopTiming.EarlyUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastEarlyUpdate), runners[3] = new PlayerLoopRunner(PlayerLoopTiming.LastEarlyUpdate));
             // FixedUpdate
-            copyList[2].subSystemList = InsertRunner(copyList[2], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldFixedUpdate), yielders[4] = new ContinuationQueue(PlayerLoopTiming.FixedUpdate),
+            copyList[(int)PlayerLoopSystemEnum.FixedUpdate].subSystemList = InsertRunner(copyList[(int)PlayerLoopSystemEnum.FixedUpdate], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldFixedUpdate), yielders[4] = new ContinuationQueue(PlayerLoopTiming.FixedUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastYieldFixedUpdate), yielders[5] = new ContinuationQueue(PlayerLoopTiming.LastFixedUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerFixedUpdate), runners[4] = new PlayerLoopRunner(PlayerLoopTiming.FixedUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastFixedUpdate), runners[5] = new PlayerLoopRunner(PlayerLoopTiming.LastFixedUpdate));
             // PreUpdate
-            copyList[3].subSystemList = InsertRunner(copyList[3], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldPreUpdate), yielders[6] = new ContinuationQueue(PlayerLoopTiming.PreUpdate),
+            copyList[(int)PlayerLoopSystemEnum.PreUpdate].subSystemList = InsertRunner(copyList[(int)PlayerLoopSystemEnum.PreUpdate], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldPreUpdate), yielders[6] = new ContinuationQueue(PlayerLoopTiming.PreUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastYieldPreUpdate), yielders[7] = new ContinuationQueue(PlayerLoopTiming.LastPreUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerPreUpdate), runners[6] = new PlayerLoopRunner(PlayerLoopTiming.PreUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastPreUpdate), runners[7] = new PlayerLoopRunner(PlayerLoopTiming.LastPreUpdate));
             // Update
-            copyList[4].subSystemList = InsertRunner(copyList[4], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldUpdate), yielders[8] = new ContinuationQueue(PlayerLoopTiming.Update),
+            copyList[(int)PlayerLoopSystemEnum.Update].subSystemList = InsertRunner(copyList[(int)PlayerLoopSystemEnum.Update], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldUpdate), yielders[8] = new ContinuationQueue(PlayerLoopTiming.Update),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastYieldUpdate), yielders[9] = new ContinuationQueue(PlayerLoopTiming.LastUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerUpdate), runners[8] = new PlayerLoopRunner(PlayerLoopTiming.Update),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastUpdate), runners[9] = new PlayerLoopRunner(PlayerLoopTiming.LastUpdate));
             // PreLateUpdate
-            copyList[5].subSystemList = InsertRunner(copyList[5], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldPreLateUpdate), yielders[10] = new ContinuationQueue(PlayerLoopTiming.PreLateUpdate),
+            copyList[(int)PlayerLoopSystemEnum.PreLateUpdate].subSystemList = InsertRunner(copyList[(int)PlayerLoopSystemEnum.PreLateUpdate], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldPreLateUpdate), yielders[10] = new ContinuationQueue(PlayerLoopTiming.PreLateUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastYieldPreLateUpdate), yielders[11] = new ContinuationQueue(PlayerLoopTiming.LastPreLateUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerPreLateUpdate), runners[10] = new PlayerLoopRunner(PlayerLoopTiming.PreLateUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastPreLateUpdate), runners[11] = new PlayerLoopRunner(PlayerLoopTiming.LastPreLateUpdate));
             // PostLateUpdate
-            copyList[6].subSystemList = InsertRunner(copyList[6], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldPostLateUpdate), yielders[12] = new ContinuationQueue(PlayerLoopTiming.PostLateUpdate),
+            copyList[(int)PlayerLoopSystemEnum.PostLateUpdate].subSystemList = InsertRunner(copyList[(int)PlayerLoopSystemEnum.PostLateUpdate], typeof(UniTaskLoopRunners.UniTaskLoopRunnerYieldPostLateUpdate), yielders[12] = new ContinuationQueue(PlayerLoopTiming.PostLateUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastYieldPostLateUpdate), yielders[13] = new ContinuationQueue(PlayerLoopTiming.LastPostLateUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerPostLateUpdate), runners[12] = new PlayerLoopRunner(PlayerLoopTiming.PostLateUpdate),
                                                                   typeof(UniTaskLoopRunners.UniTaskLoopRunnerLastPostLateUpdate), runners[13] = new PlayerLoopRunner(PlayerLoopTiming.LastPostLateUpdate));
 
             // Insert UniTaskSynchronizationContext to Update loop
-            copyList[4].subSystemList = InsertUniTaskSynchronizationContext(copyList[4]);
+            copyList[(int)PlayerLoopSystemEnum.Update].subSystemList = InsertUniTaskSynchronizationContext(copyList[(int)PlayerLoopSystemEnum.Update]);
 
             playerLoop.subSystemList = copyList;
             PlayerLoop.SetPlayerLoop(playerLoop);