diff --git a/src/state/base-state.ts b/src/state/base-state.ts
index abcadb2..6e0672a 100644
--- a/src/state/base-state.ts
+++ b/src/state/base-state.ts
@@ -163,7 +163,7 @@ export class BaseState<T> extends BaseHeadState implements State<T> {
    * If no name is given, the first action is returned. This is useful for
    * formats that only supply 1 action, and no name.
    */
-  action<TFormData = any>(name?: string): Action<TFormData> {
+  action<TFormData extends Record<string, any> = any>(name?: string): Action<TFormData> {
 
     if (!this.actionInfo.length) {
       throw new ActionNotFound('This State does not define any actions');
diff --git a/src/state/interface.ts b/src/state/interface.ts
index 74fabd4..7231c93 100644
--- a/src/state/interface.ts
+++ b/src/state/interface.ts
@@ -54,7 +54,7 @@ export type State<T = any> = {
    *
    * If the format provides a default action, the name may be omitted.
    */
-  action<TFormData = any>(name?: string): Action<TFormData>;
+  action<TFormData extends Record<string, any> = any>(name?: string): Action<TFormData>;
 
   /**
    * Returns all actions