diff --git a/src/lib/types/arrays.ts b/src/lib/types/arrays.ts
index e82cd8f3..fb4556c0 100644
--- a/src/lib/types/arrays.ts
+++ b/src/lib/types/arrays.ts
@@ -1,3 +1,5 @@
+import type { ObjectId } from "bson";
+
 export const muscleGroups: typeof MuscleGroups = [
   "Chest",
   "Front delts",
@@ -14,6 +16,8 @@ export const muscleGroups: typeof MuscleGroups = [
   "Calves"
 ] as const;
 
+export type WithUserId<T> = T & { userId: ObjectId };
+
 export const caloricStates: typeof CaloricStates = [
   {
     name: "Hypo-caloric",